Service Training Meeting Guide 746
SERV1746-01 October 2002
TECHNICAL PRESENTA PRESENTATION TION
"D" SERIES BACKHOE LOADERS INTRODUCTION
"D" SERIES BACKHOE LOADERS INTRODUCTION MEETING GUIDE 746
SLIDES AND SCRIPT AUDIENCE
Level II - Service personnel who understand u nderstand the principles of machine systems operation, diagnostic equipment, and procedures for testing and adjusting.
CONTENT This presentation discusses the design features, major components, and systems operation for the "D" Series Backhoe Loaders. Also included are descriptions of the operator's station and service points.
OBJECTIVES After learning the information in this presentation, the serviceman will be able to: 1. locate and identify identify the major major components in the operator's operator's station, power train, and machine hydraulic systems including the optional All Wheel Steer system; 2. explain the function of the major components in the power train, train, machine hydraulic systems systems and the optional All Wheel Steer system; 3. identify service points for the engine, power train, and machine hydraulic systems; systems; 4. trace oil flow flow through the transmis transmission sion and machine machine hydraulic hydraulic systems; systems; and 5. explai explain n the operation operation of the starting starting and charging charging system. system.
PREREQUISITES Interactive Video Course "Fundamentals of Mobile Hydraulics" TEMV9001 STMG 546 "Graphic Fluid Power Symbols" SESV1546 STMG ST MG 59 595 5 "In "Intr trodu oduct ctio ion n to to Load Load Sen Sensi sing ng Pre Press ssur uree Com Compen pensa sate ted d Hyd Hydra raul ulic ic Sy Syst stem ems" s" SESV SE SV15 1595 95 STMG 630 "416B - 438B 438B Backhoe Backhoe Loaders Loaders - Steering Steering and Implement Implement Hydraul Hydraulic ic Systems" Systems" SESV16 SESV1677 77 STMG 677 "416C - 438C Backhoe Loaders" SESV1677 STMG 725 "416C - 438C Backhoe Loaders -Update" SESV1725 Technical In Instruction Mo Module "A "Autoshift Tr Transmission fo for Ba Backhoe Lo Loaders" SEGV2678 Estimated Time: 8 Hours Visuals: 104 (2 X 2) Slides Serviceman Handouts: 18 Worksheets Worksheets Form: SERV1746-01 Date: 10/02 © 2002 Caterpillar Inc.
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SUPPLEMENTARY TRAINING MATERIAL STMG 62 629 "416B - 438B Backhoe Loaders–Introduction" STMG 630 "416B - 438B Backhoe Loaders–Steering and Implement Hydraulic System" STMG 604 "416 - 438 Series II Backhoe Loaders–Engine, Power Train Train and Electrical Systems" STMG 605 "416 - 438 Series II Backhoe Loaders–Steering and Implement Hydraulic System"
SESV1629 SESV1630 SESV1604 SESV1605
REFERENCES Service Manual
416D Backhoe Loaders Service Manual
RENR3570
Parts Manuals
416D Backhoe Loader BFP1-Up 416D Backhoe Loader BGJ1-Up 416D Backhoe Loader (G Version) BKG1-Up 420D Backhoe Loader FDP1-Up 420D Backhoe Loader BLN1-Up 420D Backhoe Loader BKC1-Up 420D Backhoe Loader BMC1-Up 430D Backhoe Loader BNK1-Up 430D Backhoe Loader BMC1-Up 424D Backhoe Loader BGP1-Up, BKR1-Up 428D Backhoe Loader BLL1-Up, BNB1-Up 428D Backhoe Loader BMT1-Up, BNS1-Up 438D Backhoe Loader BPE1-Up, BPN1-Up 432D Backhoe Loader BLD1-Up 442D Backhoe Loader BRG1-Up, BRY1-Up
SEBP3202 SEBP3236 SEBP3241 SEBP3203 SEBP3204 SEBP3237 SEBP3238 SEBP3205 SEBP3206 SEBP3207 SEBP3208 SEBP3209 SEBP3211 SEBP3210 SEBP3212
Operation and Maintenance Manuals
416D Operation and Maintenance Guide 420D/430D Operation and Maintenance Guide 424D/428D/438D Operation and Maintenance Guide 432D/442D Operation and Maintenance Guide
SEBU7398 SEBU7399 SEBU7400 SEBU7401
Specalogs
416D Specification Sheet 420D Specification Sheet 430D Specification Sheet
AEHQ5419 AEHQ5420 AEHQ5421
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TABLE OF CONTENTS INTRODUCTION .................................................................................................................5 ENGINE................................................................................................................................25 Fuel System.....................................................................................................................27 ELECTRICAL SYSTEM ................................................... ..................................................34 POWER TRAIN ............................................... ........................................................ ....................................................................39 ............39 Standard Transmission....................................................................................................39 Autoshift Transmission...................................................................................................44 Axles and Brakes ................................................. ........................................................ ...........................................................55 ...55 STEERING AND IMPLEMENT HYDRAULIC SYSTEMS..............................................62 Steering and Implement Pump Operation.......................................................................74 Loader Valve Valve Groups and Steering System ....................................................... ....................................................................80 .............80 Backhoe Valve Groups..................................................................................................110 All Wheel Steer System (AWS)....................................................................................133 OPTIONAL MACHINE SECURITY SYSTEM (MMS) ..................................................1 34 CONCLUSION...................................................................................................................136 SLIDE LIST........................................................................................................................137 SERVICEMAN'S HANDOUTS.........................................................................................139
"D" SERIES BACKHOE LOADERS INTRODUCTION
© 2002 Caterpillar Inc.
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INTRODUCTION • Cent Center er pivot pivot models models:: - Stan Standard dard controls controls - 416D - Pilo Pilott controls controls - 420 420D D and and 430 430D D • Side Sideshif shiftt model models: s: - Stan Standard dard controls controls - 424D - 428D - 438D - Pilo Pilott controls controls - 432D - 442D
The "D" Series Backhoe Loader Family is the latest generation of Caterpillar Backhoe Loaders retaining many of the features proven on the "B and C" Series machines along with additional performance and design improvements. This presentation discusses the systems, major components, and features of the "D" Series Backhoe Loaders. The "D" Series machines include the 416D, 420D and 430D which are equipped with the center pivot backhoe. The 420D and 430D feature pilot controlled implement hydraulics. The "D" Series also includes the 424D, 428D and 438D sideshift models which are popular in Europe. Additional sideshift models include the 432D and 442D with pilot controlled implement hydraulics. The new machine series features new paint themes to provide a bolder image.
SIMILARITIES WITH FORMER MACHINES
• Engine • Thermal Starting Aid • Radial Seal Air Filters • Standard Transmission • Steering • Brake System • Hydraulic Pump • Mechanical Implement Controls • IT Linkage • All Wheel Drive
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• Sim Simila ilarit rities ies
The "D" Series machines have many similarities to the machines they are replacing. The basic engine, standard transmission and steering systems are the same as before. The hydraulic brake system has multiple disc brakes b rakes and inboard planetaries in the rear axle. The brake system is the same except for the master cylinders being mounted differently than in the "C" Series machines. The hydraulic pump and controls are virtually the same as the "B" and late production "C" Series, except for changes in operating pressures and flow rates. Most of the daily service fill and check points can be accessed through the hinged engine hood.
DIFFERENCES FROM FORMER MACHINES
• Operator's Compartment • HVAC • Fuel Pump • Starting and Charging System • Autoshift Transmission • Hydraulic Tank • Reverse Signal System • Stabilizer Valves • Ride Control System • High Rotation Buckets • Pilot Controlled Hydraulics
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• Dif Differ ferenc ences es
The "D" Series machines feature several changes over the previous models to improve operator comfort and machine performance. The operator compartment features new console layouts. The heating, ventilation and air conditioning components are located near the floor and provide significant improvements to air circulation. The fuel pump has been changed to the type also used on the 914G Wheel Loader. The electrical system has changed significantly from the previous models. Two fuse and relay blocks are located below a cover on the right side console. The autoshift transmission is the same as the power shift transmission on the "C" Series except for the change in the software to convert to autoshift. The hydraulic tank has been redesigned. A expansion tank is no longer required. A tube has also been added to make draining the tank tank much easier.
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The signal line routing has changed. With the the reverse signal system, the last resolver in the signal network is in the loader valve group instead of the backhoe valve group as per previous backhoe models. Some machines are available with pilot operated controls for the backhoe valve group or for for both the backhoe and the loader valve groups. The pilot controls provide reduced lever efforts. The stabilizer valves on all machines are pilot controlled and are different in design from the previous versions. Ride Control is similar in operation as before, however, the system design has been modified. Due to changes in the backhoe linkage, a single pin location is able to provide improved performance for all backhoe operations. Previously Previously,, two pin positions were used.
"D" SERIES BACKHOE LOADERS CENTER PIVOT FEATURE DESCRIPTION
416D
3054 Naturally Aspirated Engine 3054 Turbocharged Engine 12-V Electrical System Standard Transmission Autoshift Transmission (option) Single Tilt IT Linkage Ride Control Pump Flow 139 L/min (37 gal/min) Pump Flow 163 L/min (43 gal/min) Dynamic Bleed Steering Maximum Pressure 20 685 kPa (3000 PSI) Maximum Pressure 22 754 kPa (3300 PSI) Mechanical Hydraulic Controls - Loader Mechanical Hydraulic Controls - Backhoe Pilot Hydraulic Controls - Loader (IT only) Pilot Hydraulic Controls - Backhoe Auto Up Stabilizers All Wheel Drive (AWD) All Wheel Steer (option) Machine Security System (option)
S O S S S O S S S S S
O
420D
SIDE SHIFT
430D
424D
428D
438D
432D
442D
S S S O O S O
S S S O
S S S O
S S S O
S O
S O
S O
S S
S S
S S
S S
S S S O
S S S O
S
S
O
O S
O
O
O S O O
S S O S
S S O S O O
S S S S O S O O
S S S O S O O
S S
S S
S S
S S
O S O O
O S O O
S = Stan tandard dard
S S S O S S S S S
O
O = Opti Optio on
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• "D" "D" Seri Series es comparison chart
This chart compares each "D" Series model to each other and reflects some of the various options and features of each machine. The 416D and 420D compete in the same size class and are replacements for the former 416C. The 416D is a lower cost version of the 420D and has fewer available options. The 416D also has slightly lower performance ratings than the 416C, while the 420D has higher performance ratings. The 430D replaces the both the 426C and 436C in the marketplace. The 420D and 430D feature pilot controls for the backhoe, while either mechanical or pilot controls are used for the loader. loader. Loader pilot controls are only for machines machines with with IT linkag linkage. e.
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Additional comparisons can be made to the sideshift machines. The 424D is the sideshift version of the 416D. The 424D, 428D and 432D compete in the same same size class. The 432D is equipped with pilot controls for both the loader and the backhoe. The other two machines feature only mechanical mechan ical controls. The 438D and 442D compete in the next higher machine class. The 442D is equipped with pilot controls. The machine security system will only be available on the sideshift machines during the initial machine introduction. introduction. The center pivot machines may have this as an option in the future. All Wheel Steer (AWS) (AWS) will not be made available on center pivot machines until further notice.
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• Cab fea featur tures es
Several cab choices are available including an enclosed Roll Over Protection System (ROPS) cab as shown and and open ROPS. The open canopy machines can be equipped with a air suspension vinyl seat, tilt steering wheel, 12 Volt Volt power supply, phone clip, a lockable left side storage space, drink holders and floor mats. On the 420D and 430D, the standard cab features an air suspension fabric seat, tilt steering wheel, 12 Volt Volt power adapter, phone clip, c lip, a lockable left side storage space, drink holders, floor mats, two doo rs, eight working lights and opening rear windows. The machines are radio ready. ready. The deluxe cab has in addition to above, a nine-way adjustable air suspension seat, auto-up stabilizer controls and additional system monitors. These monitors are for the voltmeter, voltmeter, fuel water separator, separator, engine air cleaner and hydraulic h ydraulic filters. The 416D is not available with the deluxe cab. The standard cab also features a single door which which is on the left side side of the machine. A cab upgrade is available with two doors and air conditioning. NOTE: Sideshift machines have similar cab features as the center pivot machines. Refer to the appropriate operation and maintenance manual and specalogs for more information on all models.
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• Mach Machine ine cont controls rols:: 1. Stee Steering ring wheel wheel 2. Tran Transmiss smission ion directional selector lever 3. Turn signal/wip signal/wiper er control lever 4. Fou Fourr speed speed transmission shift lever 5. Load Loader er control control lever 6. Auxi Auxiliary liary control control lever 7. Diff Different erential ial lock 8. Serv Service ice brake brake pedals 9. Gove Governor rnor pedal pedal 10. Park Parking ing brake lever
When sitting in the operator's seat and facing the front, various machine controls and features can be identified. The cab shown is a machine equipped with mechanical loader controls levers (5 and 6) to operate the front loader bucket with a single tilt cylinder. The four speed transmission shifter (4) and directional selector (2) are for machines equipped with the standard transmission. If the parking brake (10) is engaged when the operator selects FORWARD FORW ARD or REVERSE, the fault alarm sounds.
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• Mach Machine ine cont controls rols:: 1. Autos Autoshi hift ft spe speed ed and direction shuttle control 2. Lo Load ader er joys joysti tick ck 3. Au Auxil xiliar iary y but button tons s 4. Th Thum umb b sw swit itch ch 5. AWS AWS po posi siti tion on indicator gauge
On machines equipped with a autoshift transmission, the speed range selector is part of the directional shuttle control (1). Shown is the loader pilot joystick (2). The two yellow buttons (3) on the joystick can be used to control an auxiliary function or for All Wheel Steer (AWS). (AWS). AWS will only be available on sideshift machines initially. initially. The thumb switch (4) provides input to the Auxiliary Control Module (ACM). The ACM directs a variable current to two proportional solenoids mounted on the loader auxiliary valve. A switch (not shown) on the front of the joystick is used to downshift the transmission or neutralize it depending on how long the switch is held. In Autoshift Mode, if the switch is depressed for less than one second the transmission downshifts. If the switch is held longer, longer, the transmission is neutralized. In Manual Mode, the the switch will not downshift the the transmission.
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• Left fron frontt console console:: 1. Aler Alertt indic indicat ator or panel 2. AW AWD D sw swit itch ch 3. Quick Quick cou couple plerr pin pin switch 4. Conti Continu nuou ous s flo flow w switch 5. Opti Option onal al washer/sprayer switch 6. Tran Transm smis issi sion on NEUTRAL lock switch
The switches on the consoles will vary depending on how the machine is configured. The alert indicator panel (1) includes: left and right turn signals, high beams, parking brake and ride control. The All Wheel Drive (AWD) (AWD) switch (2) has three positions. One position is for AWD OFF, another for AWD ON, and the other position for AWD ON only when the brakes are applied. This last position position allows for better machine braking by locking up the entire driveline. driveline. In affect, all four wheels are used to brake the machine even though the front wheels are not equipped with brakes. A quick coupler pin switch (3) is used on machines equipped with the Integrated Toolcarrier Toolcarrier (IT) style dual tilt cylinder bucket and a nd parallel lift arms. The switch is used to release or lock the coupler pins from an attachment.
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The continuous flow switch (4), is an option that works with the proportional solenoid controlled loader auxiliary circuit. The switch is momentary.. After the desired flow rate is selected with the loader momentary joystick thumb switch. Press and release the continuous flow switch. Then release the thumb switch. The feature is used with with brooms or other attachments where continuous flow is required. The optional washer/sprayer switch (5) is used to control a separate function such as a washer for a broom. The transmission NEUTRAL lock switch (6) prevents the transmission from being shifted into a direction. The directional selector lever can be moved, but the transmission will not shift until the lock switch is turned off.
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• Righ Rightt front front console: console: 1. Fla lash sher er 2. Au Autos toshi hift ft swi switch tch 3. Ride Ride Co Cont ntro roll switch 4. COSA COSA roadi roading ng lig light ht switch location 5. Horn
The autoshift switch (2) allows the operator to switch between Manual or Autoshift Modes. In autoshift, after the the operator selects the maximum speed range on the shift selector lever, the machine automatically shifts the machine based on ground speed. Maxium speed gear in in autoshift is fifth, while manual is limited to fourth. The shift lever only shows shows up to fourth gear; however, in autoshift the transmission will shift into fifth gear based on ground speed. The Ride Control switch (3) is used to select the different modes of operation. The optional Ride Control Control system provides a smoother ride ride when the machine is driven over rough terrain. On machines equipped with autoshift, the transmission ECM monitors the position of the Ride Control switch and determines when to operate the Ride Control system. If the machine is equipped with AWS, a gauge and switches to select the AWS mode are also mounted on the right front console (not shown). (AWS (A WS will discussed later in this presentation.)
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• Load Loader er cont controls rols:: 1. Pi Pilo lott joys joysti tick ck
The loader controls are located in the side console. The side console is equipped with additional gauges, switches and controls.
2. Ale Alert rt ind indica icator tors s 3. Ke Key y star startt swit switch ch 4. Hydr Hydrau auli lic c lock lock switch 5. Go Gove vern rnor or lev lever er 6. Bo Boom om lo lock ck lev lever er 7. Stabi Stabiliz lizer er pil pilot ot control levers
The alert indicators (2) include: engine oil pressure, coolant level, charging and brake level. The additional switches and controls on the side of the console vary with machine configuration. configuration. Gauges include: include: tachometer, fuel level, coolant temperature and power train temperature. The key start switch (3) no longer has an accessory position as did the "C" Series machines. The hydraulic lock switch (4) controls a pilot shutoff solenoid valve on machines with pilot controls. The switch energizes the pilot shutoff solenoid when the key start switch is turned ON to allow pilot oil to the joysticks to operate the implements. When the key start switch switch is turned OFF or the switch is moved to the LOCK position, the joysticks are disabled.
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With mechanical controls, the hydraulic lock switch controls an optional hydraulic shutoff solenoid valve instead. When the hydraulic lock lock switch is moved to the LOCK position, the valve is energized and blocks supply oil to the backhoe valve group when roading the machine. The rear governor lever (5), boom lock lever (6), and stabilizer pilot control levers (7) are also located in the side console. The action alarm (if equipped) will sound when one or both stabilizers are raised if the transmission direction control lever is shifted from NEUTRAL. The stabilizer control system may feature auto-up, which holds the levers in detent for a set time to automatically raise raise the cylinders. The timer can not be adjusted.
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• Mechanica Mechanicall backho backhoe e controls: 1. Sw Swin ing g and and boo boom m 2. St Stic ick k and and buck bucket et 3. Bo Boom om lo lock ck lev lever er
When the operator is facing the rear of a machine on, the standard backhoe controls can be identified. The standard control pattern for the "D" Series is the same as on all previous backhoe models. The long lever on the right (2) is used to control bucket and stick. The long lever on the left (1) (1) is used to control the boom and swing. The boom lock lever (3) has been moved to the side console. A pedal or pedals (not shown) on the floor are used to control the auxiliary functions like the E-stick or a hammer ha mmer.. To satisfy the needs of the customer, optional control configurations con figurations are available.
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• Pilot Pilot opera operated ted backhoe: 1. St Stic ick k and and swin swing g 2. Bu Buck cket et and and boo boom m 3. Pods 4. Pilot Pilot con contro troll pod pod lever 5. Sw Swin ing g loc lock k pin pin 6. EE-st stic ick k ped pedal al
The backhoe controls for machines equipped with pilot controls are shown. The pilot control pattern for the "D" Series is the same as the Cat excavator pattern. The joystick on the right (2) is used to control control bucket and boom. The joystick on the left (1) (1) is used to control the stick and swing. A switch to activate the horn is part of the left left joystick. The joysticks are mounted to pods (3). The pilot control pod lever (4), locks lock s the joystick pods until the operator releases the pods in order to move the joysticks for and aft to an ergonomically correct position. E-stick pedal (6) is used to control an auxiliary valve through mechanical linkage. On some machines an additional pedal (not (not shown) can be used for an additional auxiliary function. To satisfy the needs of the customer, optional control configurations co nfigurations are available including the Cat backhoe pattern.
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• Pattern Pattern chang changer er valve valve lever:
An optional feature on machines with joystick controls is a pattern changer valve (not shown) mounted to the inside of the frame on the left side of the machine.
1. Lever 2. Hole
The lever (1) is in position #1 for the excavator control pattern. The lever can be moved to a different position to change from excavator to a backhoe control pattern. To select the backhoe control c ontrol pattern the bolt must be removed from the end of lever. lever. The lever can then be rotated to the the lower hole (2) for position #2. The bolt is then reinstalled in the hole h ole to hold the lever. The #1 and #2 are stamped into the frame.
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• "D" Serie Series s bucket buckets: s: - Buck Bucket et stop plates plates
The "D" Series backhoes feature "high rotation" rotation" backhoe linkage. A single pin bucket position contributes to 205 degrees of rotation. This is suitable for all applications eliminating the need to change pin positions as was done on all previous backhoes. An integral lifting eye (not (not shown) is a standard feature of the bucket linkage. Bucket stop plates (arrows) allow "C" Series buckets to b e used on "D" Series machines. When a "C" Series bucket is attached, attached, the plates must be moved to the other side of the linkage to limit "C" Series bucket travel. Without the stops, the "C" Series buckets will contact the stick.
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• Ser Servic vice e points: points:
Most daily service fill and check points are located below the hinged hood.
1. Air fil filter ter ho housi using ng 2. En Engin gine e oil oil fill fill tub tube e 3. En Engin gine e dip dipsti stick ck 4. Hydrau Hydraulic lic tan tank k fill fill tube 5. Transm Transmiss issio ion n fill fill tube 6. Air fil filter ter ind indica icator tor 7. Was Washer her fil filll bott bottle le 8. Br Brak ake e reser reservo voir ir
Radial seal air filters are used on these mach ines.
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• Hydrauli Hydraulic c sight sight gauge gauge (arrow)
The hydraulic sight gauge (arrow) is located on the left side of the machine in front of the cab on the loader tower.
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ENGINE • Service Service points points and components: 1. Rad Radiat iator or fil filll cap cap 2. Powe Powerr trai train n and and implement hydraulic system oil cooler 3. Co Cond nden ense ser r 4. Co Comp mpre ress ssor or 5. Fu Fuel el fil filte ter r 6. Fu Fuel el pu pump mp 7. Fu Fuel el fil filll tub tube e 8. Fuel Fuel tan tank k drai drain n plug 9. Decal
The "D" Series backhoe loaders are powered by direct injection, four cylinder, Caterpillar Caterpillar 3054T diesel engines. Most of the models are turbocharged. The 3054B naturally aspirated aspirated engines for the 416D and 424D use similar components, but are not equipped with an engine oil cooler. The 3054B is the specific model designation for the 103 mm bore engine. to meets EPA EPA Tier 1 emissions. The increased bore size gives it a total displacement of 4.43 liters. All other 3054 engines have 4.0 liter displacement. One other significant significant difference is is that the 3054B is linerless. All other 3054's are built with dry, dry, replaceable liners. In front of the radiator is a combination power p ower train and implement hydraulic system oil cooler (2). The two systems are separate, but use a common cooler assembly assembly.. If the machine is equipped with air conditioning, the condenser (3) is mounted at the front front of the engine compartment. The air dryer (not shown) is located behind the rear axle. The decal (9), identifies the access point behind the frame to drain the fuel/water separator separator..
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• Engine compartment components: 1. Therm Thermal al sta starti rting ng aid 2. Fuel Fuel lift lift (pri (primin ming) g) pump 3. Sta tarrte ter r 4. Al Alte tern rnat ator or 5. Ra Radi diat ator or
Shown here are the components on the right side of the engine compartment. The standard alternator (4) is rated for 55 amps. An optional 90 amp alternator is also available. The cooling system features an automotive-type radiator (5). NOTE: The thermal starting aid was called the start aid coil on "C" Series machines.
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FUEL HYDRAULIC SYSTEM ENGINE RUNNING BOOST PRESSURE
FUEL TANK
BOOST CONTROLLER
TRANSFER PRESSURE REGULATOR
MAIN FILTER
WATER SEPARATOR FEED PUMP
SHUTOFF SOLENOID FUEL RETURN CHECK VALVE
INJECTOR TORQUE TRIMMER
VENT ORIFICE DELIVERY VALVE
ROLLERS
ROTOR
CAM RING
TRANSFER PUMP METERING VALVE
PLUNGERS
SHOES SCROLL PLATES
AUTOMATIC ADVANCE MECHANISM
FLAT HYDRAULIC HEAD COLD ADVANCE DEVICE
ORIFICE CHECK VALVE LIGHT LOAD ADVANCE VALVE
LATCH VALVE
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Fuel System • Fuel flow flow throug through h fuel system: - Water separator/ separator/fuel fuel filter - Li Lift ft pump pump - Fuel filt filter er - Distributo Distributor-type r-type fuel injection pump - In Injec jecto tors rs
All components shown in the schematic except for the fuel tank, water separator/fuel filter, filter, lift pump, fuel filter and injector are part of the fuel injection pump. The feed or lift pump is used to move fuel from the fuel tank to a higher level on the machine. The pump is also used to to prime the system. The water separator removes water from the fuel. Since the fuel injection pump is lubricated by fuel, it is extremely important that water does not enter the pump. Water will cause the pump to malfunction and will lead to the rotor rotor and plungers locking up. The water separator should be serviced daily. daily.
- Retu Return rn to tank
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The transfer pump draws fuel from the tank and supplies fuel to the injection pump. The hydraulic head is machined with bores and passages which wh ich allow fuel to flow to and from a specific point. For example, fuel flows from from the transfer pump to the metering valve or from the metering valve to the inlet passage to the rotor rotor.. The rotor is located in the hydraulic head. The rotor distributes distributes fuel to the delivery valves. The rotor has four inlet passages passages and one outlet passage. As the rotor turns, fuel enters the passages in the rotor and forces the plungers in the the drive end of the rotor outward. outward. As the rotor continues to turn, the inlet passage closes. As the plungers are forced forced inward by the cam ring and a nd rollers, the fuel pressure in the rotor increases. At the same time, the outlet passage opens and fuel exits the rotor through the delivery valves to the injectors. The transfer pressure regulator controls the fuel transfer pressure within the injection pump. Transfer pressure will increase as engine speed increases. The regulator also permits the fuel to bypass the transfer pump when the fuel system is being primed. The shutoff solenoid allows fuel to enter the fuel injection pump when the solenoid is energized. energized. When the key start switch switch is moved to the OFF position, the solenoid is de-energized and a spring moves the plunger in the solenoid to block fuel flow. The metering valve controls the amount of fuel to the hydraulic head or rotor.. The valve is connected to a mechanical governor and the throttle rotor throttle or governor control lever. lever. As the metering valve is rotated within the hydraulic head, a delivery control groove in the valve precisely meters fuel to the rotor. A tapered flat on the metering metering valve works with the light light load valve. The flat is machined in line with the delivery de livery control groove.
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The light load advance valve and metering metering valve work with two control control orifices in the hydraulic head to override the normal speed advance system. During low load conditions, the outward outward travel of the rollers rollers and shoes is reduced during the rotor filling cycle, which delays the point of roller contact with the cam lobes resulting in retarded injection. The light load advance compensates for this delay by advancing injection at reduced fuel levels. Passageways are drilled drilled within the hydraulic head body to connect the metering valve "flat" with the pressure end of the advance device (through a second second control orifice) and the pump cambox. As the metering valve is rotated in the hydraulic head by the governor, a larger or smaller flow path from the advance piston to the cambox is created. The relationship between the "flat" with with the delivery control groove is arranged so that, as delivery d elivery is reduced, flow past the flat is also reduced. Thus, the pressure signal applied to the advance piston is increased to advance the timing. The boost controller adjusts the maximum fuel delivery based on variations in the boost pressure pressure from the turbocharger. turbocharger. As boost pressure increases, the scroll plates rotate and allow the plunger travel to increase. This action permits an increase in fuel delivery resulting in more engine horsepower. The torque trimmer provides a means to regulate the volume of fuel being delivered at full load. The torque trimmer provides the maximum amount of fuel in the loadable range of the engine which can be burned smoke free. The delivery valves are check valves which open to allow fuel from the pumping mechanism to the injectors. There is one delivery valve per injector.. The valves rapidly reduce pressure in the injector lines at the injector the end of the injection cycle to ensure a rapid closure of the injector nozzles and, in conjunction with the cam ring profile, maintain a residual pressure in the fuel lines to the injectors. The latch valve prevents transfer pressure from reaching the automatic advance mechanism during cranking until the engine is started to prevent premature advance timing.
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The automatic advance mechanism progressively advances the start of injection as engine speed increases. The automatic advance mechanism causes the cam ring to rotate rotate in the pump housing. The spring in the mechanism moves the piston and cam ca m ring to retard the timing, while transfer pressure sensed on the left side of the piston works against the spring to advance the timing. The check valve prevents reverse fuel flow from the automatic advance due to cam loading. The orifice permits fuel fuel to vent from the automatic automatic advance when the engine rpm are reduced. The cold advance device is used to reduce white smoke by advancing the engine timing to improve cold idling idling combustion capability. capability. The cold advance device is sometimes called a "wax motor" and is a relatively slow response actuator a ctuator.. At start-up, a check valve prevents preve nts transfer pressure from flowing to the right end of the automatic advance mechanism preventing the sleeve from moving away from the start advance position. This action prevents the spring from fully retarding the engine timing. After the engine is started started and allowed to warm up to a specified temperature, a coolant switch closes and current is sent to the wax motor causing the wax to melt. As the wax melts, it changes in volume and goes from a solid to a liquid. After approximately 25 seconds or more, the pin in the device moves to the left and unseats the check valve. Transfer pressure then flows to the right end of the automatic advance mechanism and moves the sleeve to the left against a stop to the normal automatic advance operating mode. The fuel return check valve maintains a slight pressure in the fuel injection pump to ensure good lubrication. The fuel return check valve also allows hot fuel to bleed from the injection pump for cooling. NOTE: Only the 430D, 438D and 442D backhoe loaders are equipped with a boost controller.
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The various color codes which are used in this presentation to identify oil flow and pressures for the fuel hydraulic system are as follows:
Pink
- Reduced transfer pressure
Red Dots
- Transfer pressure
R ed
- High pressure fuel
Blue
- Blocked fuel
Green
- Suction or drain fuel
Purple
- Boost air pressure
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FUEL INJECTION PUMP LOW IDLE STOP
THROTTLE LEVER
HIGH IDLE STOP
METERING VALVE
GOVERNOR SPRING
FUEL SHUTOFF SOLENOID VENT ORIFICE
FUEL INLET TRANSFER PRESSURE REGULATOR
FUEL RETURN CHECK VALVE SCROLL LINK PLATE
SCREEN TRANSFER PUMP
DRIVE SHAFT SHIFTER AND SLEEVE
PLUNGERS TO INJECTOR
GOVERNOR FLYWEIGHTS
SHOES SCROLL PLATES
ROLLERS
CAM RING
AUTOMATIC ADVANCE MECHANISM
ORIFICE CHECK VALVE
20
• Fuel inje injectio ction n pump pump
This illustration shows a sectional view of the fuel injection pump. Fuel is drawn by the transfer pump through the pressure regulator and sent to the metering valve when the solenoid solenoid is energized. The fuel also flows through an annular groove around the rotor to the orifice check valve and the automatic advance mechanism. The metering valve controls the amount of fuel sent to the pumping elements inside the rotor (plungers, cam ring and shoes). As the rotor turns, the cam ring forces the shoes and plungers in to increase the fuel pressure. The pressurized fuel is then directed to the injectors.
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1 2 4
3
5 6 8 7
9
21
• Fuel inje injectio ction n pump pump components:
The fuel injection pump is locate on the left side of the engine. Only the 430D, 438D and 442D are equipped with a boost controller (1).
1. Bo Boost ost con contro troll ller er 2. Fuel Fuel sh shut utof off f solenoid 3. Fuel Fuel tr tran ansf sfer er pressure regulator and inlet 4. To Torq rque ue tri trimm mmer er 5. La Latc tch h val valve ve 6. Lo Lock ckin ing g bo bolt lt 7. Autom Automati atic c adva advance nce mechanism and cold advance device 8. De Deli live very ry va valv lve e • Additio Additional nal engi engine ne component: 9. Oil pr press essure ure swi switch tch
If a new pump is installed on the engine, a locking bolt (6) and a two position spacer in the pump flange below the timing mark on the pump engine flange must be loosened after installing the pump on the engine. In the locked position, the bolt bo lt prevents the pump drive shaft from turning. Move the spacer to provide additional clearance between the bolt head and the pump flange to unlock the pump drive shaft. If this procedure is not performed, the fuel pump will be damaged if an attempt is made to start start the engine. If the timing pin was used this bolt may not have been used to prevent the pump drive shaft from turning. The oil pressure switch (9) can be removed remove d to install a test nipple to check chec k engine oil pressure. NOTE: Refer to service manual module "Lucas Fuel Pump Supplement" (Form SENR6525) for more information on removing and installing the fuel injection pump. This is the same type of fuel pump used on the 914G and IT14G.
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"D" SERIES STARTING AND CHARGING SYSTEM EMISSIONS ENGINE / RUN G
S
MT R
BAT
ACTION LAMP GROUP
101-RD
MOTOR
STARTER
450-YL
309-GY 101-RD
1 2 3 L IG P
TACH.
CBL RD-00 338-PK
B+
ATTACHMENT RELAY
POS NEG
TO FUSES
ALTERNATOR
ALT
POS NEG
COLD START TEMP. SW.
A C
334 BU
327-PK
COLD START ADVANCE SOLENOID
T
°
TO RR LIGHTING RELAY TO HVAC RELAY
327-PK
338-PK
CAB RELAY
1 2
A B
A C
TO FUSES
FUEL SHUTDOWN SOLENOID
131-RD
FUSE RELAY BLOCK 2 123-WH
308-YL
TO FUSES 10A TRANSMISSION
15 A THERMAL START AID
MAIN RELAY A C
10A ENGINE FUEL
BATTERY GROUND FORWARD SOL RETURN REVERSE SOL RETURN FORWARD SOL. OUT REVERSE SOL. OUT START RELAY COIL OUT KEY START SW. TO BAT NEUTRALIZER SW. TO BAT PARK BRAKE ALARM OUT PARK BRAKE SW. TO GND. NEUTRAL LOCK SW. TO GND.
1 2 3 4 5 6 7 8 9 10 11 12
310-PU
202-BK
START AID SW.
SHUTTLE CONTROL
THERMAL STARTING AID
R
306-GN START RELAY 20A
304-WH
101-RD
START RELAY
TO FUSES KEY START
307-OR
TO FRONT LIGHTING RELAY
1 2 3 4
C S B
OFF ON ST
KEY START SWITCH
A C
5A 105-RD
FUSE RELAY BLOCK 1
22
ELECTRICAL SYSTEM • Starti Starting ng system system operation: - Bat Batter teries ies - Key start start switch switch to START-RUN - Ener Energize gize shutdown shutdown solenoid - Transmission shuttle control in NEUTRAL - Star Startt relay closes closes - Ener Energize gizes s starter solenoid
This schematic shows the 12-V 12-Volt olt electrical starting and charging system with the key start switch in the RUN position. position. From the batteries, power flows to the battery post on the starter, starter, to the fuse relay blocks. From Fuse Relay Block 1, power flows to the key start switch. When the key is in the ST START ART-RUN -RUN position and the transmission shift control lever is in NEUTRAL, the start relay is energized through the transmission shuttle control (shift (shift lever). With the start start relay closed, power from the battery energizes the starter solenoid solenoid and motor. The starter then engages the flywheel flywheel ring gear and starts the engine. If the transmission shuttle control is not in NEUTRAL, no power is directed to the start relay, so the engine will not crank.
- Turn Turns s starter motor motor
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STMG 746 STMG 10/02
• Key start start swit switch ch in in START or RUN: - Fuel shut shutoff off solenoid energized • Key start start swit switch ch to to OFF: - Fuel shut shutoff off solenoid de-energized
- 35 -
When the key is in either the ST STAR ART T or RUN position, the fuel shutoff solenoid is energized and allows fuel to flow through the fuel injection pump. Thus, the solenoid is "energized to run." Turning the key start switch to the OFF position de-energizes the engine shutdown solenoid. The solenoid moves the metering valve linkage linkage to the "fuel off" position. For cold starts, the start aid switch can be used to energize the thermal starting aid while cranking the the engine. When the start aid switch switch is closed, power to the thermal starting aid heats the coil. Expansion within the coil assembly permits fuel to flow through a check valve when the engine is cranked. The heated fuel becomes a vapor and, as it flows past the coil into the inlet manifold, the fuel is ignited. The ignited fuel heats the inlet air. When the key start switch is turned to the RUN position or the start aid switch is released, the the inlet air cools the coil assembly quickly. quickly. The check valve closes and blocks the fuel supply line.
• Chargin Charging g syste system m operation: - Key start start in RUN - Smal Smalll current current excites alternator - Alte Alternat rnator or charges batteries and powers accessories - Mai Main n relay relay closed–power to accessories and other relays
The battery is charged by a belt-driven belt-driven alternator. alternator. The alternator is not self-energizing and requires battery voltage to start up. When the key start switch is in the RUN position, power from the battery goes through the switch to the "IG" terminal of the alternator to excite the alternator field. With the key start With start switch switch in the RUN posit position, ion, the main main relay is closed closed and power is directed to the accessories and additional relays. The cold start advance solenoid does not energize until the cold start temperature switch closes.
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2
3 1
23
• Elec Electrica tricall system system::
The "D" Series backhoe loaders are equipped with conventional 12-V 12-Volt olt electrical systems with negative ground.
- 12-Vo 12-Volt lt system system - One batter battery y is standard - No discon disconnect nect switch
The standard machines are equipped with a 12-Volt 12-Volt maintenance free battery to supply power to the system. The machines can be equipped with two batteries along with a heavy duty alternator for cold weather climates or for use with additional operating lights (attachments). The system does not have a disconnect disconnect switch. To disable the electrical system, remove the battery ground cable from from the main frame. The starting system is a key start and stop system.
• Autos Autoshi hift ft transmission: 1. Au Auto tosh shif iftt ECM ECM 2. Diag Diagno nost stic ic indicator lamp 3. DT co conn nnec ecto tor r
The Autoshift ECM (1) for a machine equipped equ ipped with an autoshift transmission is also located in the battery compartment. The diagnostic indicator lamp (2) is used to access active fault information from the control control module. The indicator flashes 2-digit fault codes. The harness connector is is a two-pin plug DT connector (3) with an end-termination receptacle.
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During normal operation this plug is installed in the connector. "If a system problem is detected by the transmission control, the diagn ostic indicator will turn on and remain on as long as the problem is active." Turning "on" means the diagnostic indicator will cycle through a ll flash codes present. Removing the termination plug from the connector co nnector will cause the lamp to flash the first active (low number to high number) two digit fault the transmission control finds. The problem is displayed by blinking the diagnostic indicator. indicator. A valid diagnostic code will consist consist of a series of blinks, (which is the first digit), digit), followed by a short pause, and then a second series of blinks (which is the second digit). digit). If no active problems are present, the control will broadcast diagnostic code "11". NOTE: Also, located in the battery compartment, but not shown, is a bolt used to manually lower the pilot controlled controlled implements. The bolt provides dead engine lowering capabilities. The bolt should only be used for lowering the loader end and not the backhoe, due to safety concerns.
STMG 746 STMG 10/02
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1
2 3
24
• Electr Electrica icall components: 1. Fuse Fuse an and d rel relay ay block 1 2. Fuse Fuse an and d rel relay ay block 2 3. Diag Diagno nost stic ic connector
The fuse and relay blocks (1 and 2) are located below covers on the right side of the cab. The diagnostic connector (3) to connect Electronic Technician (ET) is also shown. Additional relays (not shown) are located in the side console. Access to these relays is obtained by moving the gauge and switch panel in the side console shown earlier earlier..
STMG 746 STMG 10/02
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TORQUE CONVERTER HOUSING
FORWARD CLUTCH
IDLER SHAFT REVERSE CLUTCH
PUMP
STANDARD BACKHOE LOADER TRANSMISSION
INPUT SHAFT
COUNTERSHAFT OUTPUT SHAFT
SPEED GEAR AWD SHAFT
SYNCHRONIZER ASSEMBLY
AWD CLUTCH
25
POWER TRAIN • Stan Standa dard rd transmission: - Fou Four-sp r-speeds eeds - Dire Directio ctional nal clutches controlled by solenoids
Standard Transmission
The standard countershaft transmission is the same as the "C" Series transmission. The four-speed, direct drive, helical gear, constant mesh, synchronized standard transmission is coupled cou pled with hydraulically h ydraulically engaged FORW FORWARD ARD and REVERSE clutches. Each multiple disc clutch pack is controlled by a solenoid valve. A manually actuated lever and shifter fork arrangement shifts the transmission through the four fully synchronized speed ranges.
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STMG 746 STMG 10/02
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Power is transmitted from the torque converter to the input shaft. If FORWARD FORW ARD is selected, the FORW FORWARD ARD clutch is engaged and power flows from input shaft to the countershaft. The countershaft causes all four speed gears to rotate. A synchronizer will engage one of the speed gears with the output shaft. shaft. Power is then directed to the the rear axle. • AWD: - Solenoid controlled clutch - Swit Switch ch on front front console
If the machine is equipped with All Wheel Drive (AWD), (AWD), a separate shaft and clutch are needed. An additional gear on the output shaft shaft will transmit power to the AWD AWD shaft. A multiple disc clutch is part of the AWD AWD shaft group. The clutch is hydraulically engaged and spring released. A solenoid controlled valve (not shown) directs oil to pressurize or drain the clutch. The solenoid is connected to a switch on the front front console (shown earlier). The front wheel drive axle can be engaged while the vehicle is moving by operating the switch. INSTRUCTOR NOTE: The various INSTRUCTOR various color codes codes which will be used used in this presentation to identify oil flow and pressures for the power train hydraulic system are as follows:
R ed
- Pump supply or directional clutch pressure
Orange
- Torque converter inlet pressure
Brown
- Lube oil
Green
- Suction or drain oil
STMG 746 STMG 10/02
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STANDARD POWER TRAIN HYDRAULIC SYSTEM
R
NEUTRAL
FILTER
F RELIEF VALVE
PUMP SUPPLY PUMP
SUCTION SCREEN
DIRECTIONAL SELECTOR SOLENOID VALVE
TORQUE CONVERTER INLET
TORQUE CONVERTER INLET RELIEF VALVE
TRANSMISSION LUBE LUBE
OIL COOLER
TORQUE CONVERTER
TORQUE CONVERTER OUTLET
26
• Two Two Wheel Wheel Driv Drive e components: - Suct Suction ion screen screen - Pu Pump mp - Oil filt filter er - Dire Directio ctional nal selector solenoid valve - Reli Relief ef valve - Torq Torque ue converter converter inlet relief valve - Co Cool oler er
This illustration shows the power train hydraulic schematic for the standard transmission equipped with Two Wheel Drive. Oil from the sump is drawn though a suction screen by a crescent-type gear pump located on the transmission transmission input shaft. From the pump, the oil is sent through a spin-on filter to the transmission directional selector solenoid valve. In NEUTRAL, the oil flow is blocked by the directional selector solenoid valve. Therefore, the oil opens the relief relief valve and flows to the torque converter. A bypass orifice in the relief valve, is located between the supply circuit and torque converter circuit to mak e sure that oil is always available to the torque converter when the machine is running.
- Lube circuit
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STMG 746 STMG 10/02
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The torque converter inlet relief valve protects the automotive-type torque converter from high pressure (during cold start-up). Oil from the torque torque converter goes to the oil cooler, which is located in front of the radiator. From the cooler, cooler, the oil is used for lubrication. A passage directs lube oil to the input shaft of the transmission. Oil from the shaft cools and lubricates the clutch assembly and input shaft bearings. The output shaft, countershaft and reverse idler shaft shaft are splash lubricated. The oil then returns to the sump. NOTE: The lines and and fittings fittings from the the torque torque converter converter and the oil cooler are sized to provide sufficient restriction to the oil in the torque converter.. A torque converter outlet relief valve is not required. converter The cold start relief valve between the pump and filter on the "C" Series has been removed on the "D" Series. The valve is no longer required.
STMG 746 STMG 10/02
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STANDARD POWER TRAIN HYDRAULIC SYSTEM
R
ALL WHEEL DRIVE / FORWARD
FILTER
F AWD SOLENOID VALVE AWD
PUMP SUPPLY PUMP
SUCTION SCREEN
RELIEF VALVE DIRECTIONAL SELECTOR SOLENOID VALVE
TORQUE CONVERTER INLET
TORQUE CONVERTER INLET RELIEF VALVE
TRANSMISSION LUBE LUBE
OIL COOLER
TORQUE CONVERTER
TORQUE CONVERTER OUTLET
27
• AWD comp componen onents: ts: - AWD sol soleno enoid id and clutch
This illustration shows the power train hydraulic schematic for the standard transmission equipped with All Wheel Drive (AWD). The power train hydraulic system for AWD machines is the same as the two wheel drive machines except for an external supply line which directs supply oil to the AWD AWD solenoid valve. When the solenoid is energized, energized, oil engages engages the AWD AWD clutch clutch.. This schematic shows that the directional selector solenoid valve has been energized. Supply oil flows through the valve to engage the FORWARD FORWARD clutch. The relief valve limits the maximum clutch pressure. pressure.
STMG 746 STMG 10/02
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AUTOSHIFT TRANSMISSION SOLENOID VALVES
PUMP
INPUT SHAFT
COUNTER SHAFT
OUTPUT SHAFT
AWD SHAFT
28
Autoshift Transmission • Autos Autoshi hift ft transmission: - Five-spee Five-speeds ds forwa forward, rd, three-speeds reverse transmission - Thre Three e speed speed solenoids - Three Three dire directio ctional nal solenoids
A torque converter (not shown) provides a fluid connection between the engine and the transmission. The five-speeds forward, three-speeds reverse, autoshift transmission is a constant-mesh, countershaft design. design. The transmission transfers power to the drive axles. The Autoshift ECM electronically controls the transmission by selectively energizing speed and directional solenoids. The transmission is equipped with three speed a nd three directional solenoids. One speed solenoid and one directional solenoid must be simultaneously energized for a transmission gear to be engaged. Transmissions with the optional AWD system are equipped with an AWD Transmissions solenoid and an additional output shaft. NOTE: The reverse shaft and clutch are not shown in this sectional view. It is shown later in this presentation.
STMG 746 STMG 10/02
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AUTOSHIFT POWER TRAIN HYDRAULIC SYSTEM
DATA LINK SERVICE PORT
NEUTRAL PARKING BRAKE SWITCH
SHIFT LEVER RIDE CONTROL SWITCH
DOWNSHIFT/NEUTRALIZER SWITCH
AUTOSHIFT ECM
AUTO/MANUAL SWITCH
TRANSMISSION OUTPUT SPEED SENSOR
NEUTRAL LOCK SWITCH
RIDE CONTROL DISABLE
REGULATED PRESSURE
ORIFICE 5
FILTER
6
2
1
3
HI R
2
3
FORWARD
LO
PUMP SUPPLY PUMP SUCTION SCREEN
SOLENOID VALVE
4
RELIEF VALVE
1
TORQUE CONVERTER INLET TORQUE CONVERTER
TRANSMISSION LUBE OIL COOLER
TORQUE CONVERTER OUTLET
LUBE
TORQUE CONVERTER INLET RELIEF VALVE
29
• Autoshif Autoshiftt power power train train hydraulic system in NEUTRAL
This illustration shows the power train hydraulic schematic for the autoshift transmission equipped with Two Wheel Drive.
• Co Compo mponen nents: ts:
Oil from the sump is drawn though a suction screen by a crescent-type gear pump located on the transmission transmission input shaft. From the pump, the oil is sent through a spin-on filter to the transmission solenoid valves.
- Su Sucti ction on scree screen n - Pump - Oi Oill filt filter er - So Solen lenoi oid d valve valve - Rel Relief ief val valve ve - Torque Torque conv converter erter inlet relief valve
In NEUTRAL, the oil flow is blocked by the solenoid valves. The supply oil opens the relief valve and flows flows to the torque converter. converter. A bypass orifice in the relief valve is located between the supply circuit and torque converter circuit to make sure that oil is always available to the torque converter when the machine is running.
- Oil coo cooler ler and bypass - Lu Lube be cir circui cuitt - ECM
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STMG 746 STMG 10/02
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The torque converter inlet relief valve protects the automotive-type torque converter from high pressure (during cold start-ups). Oil from the torque converter goes to the oil cooler, which is located in front of the radiator. An oil cooler bypass valve is used to protect the cooler from excessive pressure caused by cold oil. From the cooler, cooler, the oil is sent sent to the transmission transmission circuit. A passage directs lube oil to the input shaft of the transmission. Oil from the shaft cools and lubricates the clutch assembly and input shaft bearings. The output shaft, countershaft and reverse idler shaft are splash lubricated. The oil then returns to the sump. Orifices in the solenoid valves provide for some clutch modulation when a speed and direction are selected. • Au Autos toshi hift ft ECM ECM
The Autoshift ECM contains the software to control the shifting of the transmission. The software compares the input information to the the information stored in the Autoshift ECM to determine the appropriate gear for the machine. The Autoshift ECM then sends output signal to energize solenoids for the appropriate clutch. Through ET, ET, FIRST gear can be ENABLED or DISABLED. FIRST gear is a relatively low (slow) gear ratio, and using it may not be necessary for normal loader work work or for roading. If using AUTOSHIFT AUTOSHIFT for either loading or roading, disabling FIRST g ear eliminates a extra gear shift. In extreme hard digging conditions, the neutralizer neutralizer button can be used to downshift to FIRST FIRST,, and then AUTOSHIFT will upshift the transmission as the machine speed increases. In summary, disabling FIRST makes the tractor more responsive, smoother, and efficient (more productive). productive). Use FIRST gear only when required. NOTE: The lines and and fittings fittings from the the torque torque converter converter and the oil cooler are sized to provide sufficient restriction to the oil in the torque converter.. A torque converter outlet relief valve is not required. converter The cold start relief valve between the pump and filter on the "C" Series has been removed on the "D" Series.
STMG 746 STMG 10/02
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AUTOSHIFT POWER TRAIN HYDRAULIC SYSTEM
DATA LINK SERVICE PORT
ALL WHEEL DRIVE / SECOND FORWARD NEUTRAL LOCK SWITCH
PARKING BRAKE SWITCH AUTOSHIFT ECM
RIDE CONTROL SWITCH AUTO/MANUAL SWITCH
DOWNSHIFT/NEUTRALIZER DOWNSHIFT/NEUTRA LIZER SWITCH TRANSMISSION OUTPUT SPEED SENSOR
SHIFT LEVER
RIDE CONTROL DISABLE
REGULATED PRESSURE ORIFICE
5
6
2
1
3 AWD
HI R
2
3
FILTER
FORWARD
LO
SOLENOID VALVE
4
1 RELIEF VALVE
TORQUE CONVERTER INLET
PUMP SUPPLY TRANSMISSION LUBE
PUMP
OIL COOLER
TORQUE CONVERTER
LUBE
TORQUE CONVERTER OUTLET
SUCTION SCREEN
TORQUE CONVERTER INLET RELIEF VALVE
30
• Autos Autoshi hift ft transmission - AWD
Here is the power train hydraulic schematic for the autoshift transmission equipped with All Wheel Drive (AWD). (AWD).
• SECO SECOND ND SP SPEE EED D FORWARD:
The power train hydraulic system for AWD AWD machines is the same as the two wheel drive machines except for the AWD solenoid and clutch. When the AWD AWD soleno solenoid id is energized, energized, oil engages the the AWD AWD clutch clutch..
- No. No. 1 and and 4 solenoids energized
This schematic shows the No. 1 and No. 4 solenoids have been energized to engage the forward forward high direct directional ional clutch clutch and the No. 1 speed clutch clutch to obtain SECOND SPEED FORWARD. FORWARD. The relief valve limits the maximum clutch pressure.
STMG 746 STMG 10/02
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REVERSE
AUTOSHIFT TRANSMISSION FORWARD HIGH
FORWARD LOW
INPUT SHAFT CLUTCH 1
CLUTCH ENGAGEMENT GEAR
FWD LOW
FWD HIGH
5F
X
4F
X
3F
1
X
2F 1F
REV
X X
2
3
SOLENOID
X
1 AND 6
X
1 AND 5
X
3 AND 5
X
1 AND 4
X
3 AND 4
N
COUNTER SHAFT CLUTCH 3
OUTPUT SHAFT AWD CLUTCH
––
1R
X
2R
X
3R
X
X
CLUTCH 2
2 AND 4 X
AWD SHAFT
2 AND 5 X
2 AND 6
31
• Autos Autoshi hift ft transmission logic chart
The five-speeds forward, three-speeds reverse transmission is equipped with six clutch packs. The autoshift transmission uses six solenoids to control the engagement of the clutch packs. Two clutch packs must be simultaneously engaged for the transmission to drive the machine. The above chart shows the energized solenoids and the engaged clutch packs for each gear. gear. The solenoids are controlled by the Autoshift Autoshift ECM. In NEUTRAL, none of the solenoids are energized. The chart can be used to identify which solenoids are energized to engage the speed and direction clutches to obtain the desired speed range. NOTE: The Autoshift ECM does not provide shift protection on the "D" Series. Some shift protection is provided for the 446B backhoe loader.. Shift protection prevents the operator from changing loader directions at high speeds.
STMG 746 STMG 10/02
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AUTOSHIFT ELECTRONIC TRANSMISSION CONTROL SYSTEM FORWARD HIGH No. 1 SOLENOID
CAT DATA LINK KEY START SWITCH
SHIFT LOADER LOCK RELAY
LEVER CONTROL
PARKING BRAKE SWITCH NEUTRAL LOCK SWITCH
BACKUP ALARM
REVERSE No. 2 SOLENOID
RIDE CONTROL SWITCH
START RELAY
TRANSMISSION OUTPUT SPEED SENSOR AUTO/MANUAL SWITCH RIDE CONTROL DISABLE SWITCH
FORWARD LOW No. 3 SOLENOID
AUTOSHIFT ELECTRONIC CONTROL MODULE
SPEED CLUTCH 1 No. 4 SOLENOID SPEED CLUTCH 2 No. 5 SOLENOID SPEED CLUTCH 3 No. 6 SOLENOID PARK BRAKE ALARM RELAY RIDE CONTROL RELAY
DOWNSHIFT/ NEUTRALIZER SWITCH
DIAGNOSTIC INDICATOR and DATA LINK SERVICE PORT
32
• Autos Autoshi hift ft ECM ECM operation
The Autoshift ECM has two modes of operation: Automatic and Manual. In the Automatic Mode of operation, the operator controls the highest desired gear and the transmission control automatically selects the proper gear based on machine ground speed. The transmission determines the ground speed through the transmission speed sensors and energized speed clutch. In the Manual Mode, the transmission operates very similar to the standard power shift transmission. transmission. In this presentation, the Automatic Mode will be discussed except where it is stated that the Manual Mode is being discussed.
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STMG 746 STMG 10/02
• Shif Shiftt lever lever control control:: - Inputs Inputs in Auto Autoshif shiftt ECM through Cat Datalink
- 50 -
When the key start switch is ON, the transmission shift lever control provides input to the Autoshift ECM through the CAT CAT Datalink. The Autoshift ECM uses the input from the shift lever control to de termine the gear range selected on the transmission shift lever control and the position of the key start switch. When the key start switch is moved into the START START position, the key k ey start switch directs power to to the shift lever control. The shift lever control, must be in NEUTRAL to signal the Autoshift ECM that the key start switch is in the START START position. position. The shift lever control completes the circuit between the key start switch and the start relay. relay. The start relay is energized, allowing power to the starter to crank the engine. If the shift lever control is not in NEUTRAL during starting, the Autoshift ECM will prevent the machine from starting.
• Parki Parking ng brake brake switch: switch: - Sign Signals als Autoshift Autoshift ECM - Auto Autoshif shiftt ECM prevents transmission from shifting if parking brake ENGAGED
The parking brake switch provides an input signal to the Autoshift ECM. The parking brake switch is closed when the parking brake is ENGAGED and open when the parking brake is RELEASED. If the shift lever control is in NEUTRAL with the pa rking brake ENGAGED and is then moved out of NEUTRAL, the Autoshift ECM prevents the transmission from shifting shifting and energizes the parking brake relay to sound the alarm. The Autoshift ECM will allow the transmission to shift when the parking brake is ENGAGED if the shift lever control is cycled into and out of the NEUTRAL position twice within a span of three seconds. If the shift lever control is shifted from NEUTRAL when the parking brake is ENGAGED, the Autoshift ECM records a parking brake event. When the parking brake is RELEASED and the shift lever control is moved out of the NEUTRAL position, p osition, the Autoshift ECM directs output signals to the appropriate transmission transmission control solenoids. solenoids. The Autoshift ECM energizes one speed speed and one directional solenoid to engage clutches in the transmission.
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If the parking brake is ENGAGED while the transmission is in a gear, the ECM shifts the transmission into NEUTRAL and energizes the parking brake relay. relay. The transmission will remain in NEUTRAL until the shift lever control is moved into the NEUTRAL position and the parking brake is RELEASED. The shift lever control can then be used to select a gear. gear. • Transmiss Transmission ion neutr neutral al lock switch - Neut Neutrali ralizes zes transmission in LOCK position
• Transm Transmiss ission ion downshift/neutralizer switch
- Downshift function
The transmission neutral lock switch also provides an input signal to the Autoshift ECM. If the transmission transmission neutral lock switch is moved to the LOCK position, the Autoshift ECM shifts the transmission transmission into NEUTRAL and prevents the transmission from shifting, regardless of the position of the shift lever control. The Autoshift ECM will not shift the transmission until after the shift lever control is moved into the NEUTRAL position and the transmission neutral lock switch is moved to the UNLOCK position. The transmission is neutralized as soon as the neutralizer/downshift button is pressed. If the button is released within one second, the transmission is downshifted one gear by moving from the neutralized state to the downshifted state. If the button is held for more than one second, the transmission will remain neutralized until the button is released. When the transmission is downshifted with the downshift function, the transmission control will hold the machine in the downshifted gea r for five seconds before the machine returns to the Automatic Mode. The downshift function is implemented by the Neutralizer/Downshift input, which is a dual function input. When downshifted, with the shifter in the third or fourth position, the Autoshift ECM downshifts the transmission one gear per actuation of the button. If the operator gives multiple downshift commands, within five seconds, the transmission will be downshifted once in response to the first command. The machine will downshift again if transmission output speed is below runout speed for the next lower gear. If the machine is above the runout speed for the next lower gear, the transmission control will not downshift until the machine is below the runout speed. If the transmission transmission is in FIRST gear when a downshift command is issued, the command will be ignored.
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If the shift lever is in SECOND, the downshift button will force the machine to be downshifted at once and held in FIRST until a speed or direction change or the five second delay is over. - Neut Neutrali ralizer zer func function tion
When a neutralizer request is initiated by the operator, the transmission will momentarily neutralize by de-energizing de-energizing the direction clutch. clutch. Only the directional clutch is de-energized. de-energized. This will improve shift shift speed when the button is released and the machine is placed back into gear. In the Manual Mode, the Downshift/Neutralizer Switch will not permit the transmission to be downshifted.
• Transmiss Transmission ion spee speed d sensor: - Prov Provides ides input input to Autoshift ECM - Auto Autoshif shiftt ECM uses input to determine downshifts
The transmission speed sensor provides output speed information to the Autoshift ECM. In the Automatic Mode of operation, the operator controls the highest desired gear and the transmission control automatically selects the proper gear based on machine ground speed. The Autoshift ECM determines the ground speed through the transmission speed sensors and energized speed clutch. If the machine is in FOURTH, as the ground speed increases, third ge ar may be skipped as the machine upshifts. This is done through the software to improve shift shift performance. This feature is called Skip-Shift Logic. In Auto Mode, 3rd gear can be skipped skipped on up-shifts only, only, allowing the transmission to shift from 2nd to 4th. If the 2nd to 4th shift shift point is not reached in a specific amount of time (0-1sec) the transmission will shift to 3rd gear. gear. The default mode for the skip-shift is to have the timer value set to zero (disabled). There is a configuration option through through ET to allow for enabling of Skip-Shift. If desired, fifth gear may be enabled or disabled through ET in order to comply with regulations in certain countries.
• Dead engi engine ne lower lower relay
The dead engine lower (loader lock) relay is part of the loader lock valve attachment to control the loader hydraulic lock valves. The input from the loader lock relay is used by the Autoshift ECM to determine if the start relay should be energized. If the loader control lever is in the "FLOAT" "FLOAT" position the Autoshift ECM will not allow the machine to start. This action prevents the loader arms from unexpectedly lowering during machine start-up when the machine is equipped with hydraulic lock valves. NOTE: Fourth gear may also be enabled or disabled through ET. ET.
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AUTOSHIFT TRANSMISSION 1ST GEAR ENABLED SHIFT LEVER POSITION
GEARS AVAILABLE 1, 2, 3, 4, 5
4F 3F
1, 2, 3
2F
1, 2
1F
1
N 1R
1
2R
1, 2
3R
1, 2, 3
33
• Gear Gear selecti selection on in Autoshift (FIRST gear is enabled)
With FIRST gear enabled, the following gears are available in the given conditions. Shift lever in FIRST: The transmission will be held in FIRST gear. Shift lever in SECOND: The transmission will automatically shift between FIRST and SECOND in response to machine speed. Shift lever in THIRD: The transmission will automatically shift between FIRST, FIRST, SECOND and THIRD in response to machine speed. The downshift switch can be used to force the transmission into FIRST or SECOND gear. Shift lever in FOURTH: The transmission will automatically shift between FIRST through FIFTH in response to machine speed. THIRD gear may be skipped by the software. software. The downshift switch can be used used to force the transmission into FIRST, FIRST, SECOND, THIRD or FOUR FOURTH TH gear.
Whenever a machine is downshifted into a lower gear, the machine maximum gear will be limited to the lower gear g ear for five seconds, then return to normal Automatic Mode.
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AUTOSHIFT TRANSMISSION 1ST GEAR DISABLED SHIFT LEVER POSITION
GEARS AVAILABLE 2, 3, 4, 5
4F 3F
2, 3
2F
2
1F
1
N 1R
1
2R
2
3R
2, 3
34
• Gear Gear selecti selection on in Autoshift (FIRST gear is disabled)
With FIRST gear disabled, the following gears are available in the given conditions. Shift lever in FIRST: The transmission will be held h eld in FIRST. Shift lever in SECOND: The transmission will be held in SECOND unless the operator forces the transmission into FIRST through the downshift switch. Shift lever in THIRD: The transmission will automatically shift between SECOND and THIRD in response to machine speed. The downshift switch can be used to force the transmission into FIRST or SECOND gear. Shift lever in FOURTH: The transmission will automatically shift between SECOND through FIFTH in response to machine speed. THIRD gear may be skipped by the software. software. The downshift switch can be used used to force the transmission into FIRST, FIRST, SECOND, THIRD or FOUR FOURTH TH gear.
If the machine is downshifted into a lower gear, upshifts will be disabled for five seconds, then return to normal Automatic Mod e.
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REAR AXLE FIXED RING GEAR
PINION GEAR AND SHAFT
FROM MASTER CYLINDER
DIFFERENTIAL LOCK ACTUATOR DIFFERENTIAL LOCK ASSEMBLY
PLANET GEAR
MULTI-DISC BRAKE ASSEMBLY
BEVEL GEAR
DIFFERENTIAL ASSEMBLY
35
Axles and Brakes • Fe Feat atur ures es:: - Hydr Hydrauli aulically cally engaged brakes same as "B" and "C" Series - Diff Differen erential tial lock same as "B" and "C" Series
The standard rear axle is similar to the "B" and "C" Series. Differential lock operation and power flow through the rear ax le are the same as with the "B" and "C" Series. The hydraulically engaged brakes are the same as "B" and "C" Series. If the machine is equipped with All Wheel Steer, an axle with a limited slip differential is used instead of differential lock.
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BRAKE MASTER CYLINDERS RIGHT BRAKE RELEASED
LEFT BRAKE ENGAGED TO BRAKE PISTON
FROM RESERVOIR
TO BRAKE PISTON SUPPLY PORT
VALVE STEM
PLUNGER
COMPENSATION VALVE
PLUNGER
BRIDGE PIPE PUSH ROD
36
• Brake Brake mas master ter cylinders: - Left and and right master master cylinders the same - Reser Reservoir voir supplies supplies master cylinder • EN ENGA GAGE GED D
This illustration shows the master cylinders. Both the right and left master cylinders are the the same. Fluid from the brake fluid fluid reservoir enters each master cylinder through the supply supply port. Fluid from the reservoir reservoir fills the spring spring chamber and the supply line to the the brake piston. The spring and plunger prevent the valve va lve stem from closing the supply port. When the operator depresses one of the brake pedals, the push rod moves against the plunger. plunger. As the plunger moves to the the up, trapped oil inside the plunger moves the valve stem up to block the supply port. Fluid pressure in the spring chamber increases. increases. As fluid pressure in the spring chamber increases, the pressure unseats the compensation valve on the left allowing oil to flow to the other master cylinder through the bridge pipe.
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The compensation valve in the right master cylinder blocks the oil in the bridge pipe from entering the right master cylinder. cylinder. As the plunger continues to move up, it will eventually block the inlet to the compensation valve. At the same time that oil enters the compensation c ompensation valve, oil enters the outlet pipe to the brake piston. As pressure increases behind the brake piston, the piston pushes the discs and plates together against the brake housing to ENGAGE the brake. If the operator engages both brakes simultaneously, both compensation valves open allowing the pressure in the spring chamber of both master cylinders to equalize. The distance the operator depresses the brake pedal determines the pressure that the piston exerts on the plates and discs. The farther the operator pushes the brake pedal, the more pressure the piston applies to the plates and discs and, therefore, the greater the braking force. • RE RELE LEAS ASED ED
• AWS
When the operator releases the brake pedal, the spring in the master cylinder moves the valve stem away from the inlet port reducing the pressure behind the brake piston. A seal around the piston moves the piston away from the discs and plates to RELEASE the brakes. The same brake valve is used on machines equipped with All Wheel Steer (AWS).
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2
4
1
3
37
• Rear Rear ax axle le components: 1. Hose Hose fro from m mast master er cylinder 2. Differ Different ential ial loc lock k linkage 3. Par Parkin king g brak brake e disc disc 4. Parkin Parking g brak brake e pad pad assembly
On the rear axle, the hose (1) is connected to the the master cylinder outlet pipes and directs oil to the brake actuator pistons. A bleed screw (not shown) next to the hose allows bleeding of the brake lines. Mechanical linkage from the parking brake lever engages the caliper and disc-type parking brake (3 and 4). The parking brake is on the drive drive shaft between the transmission and the rear axle. The parking brake needs to be checked and possibly adjusted at regular intervals.
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1
3
2
38
• Power Power tra train in components: 1. Brak Brake e mast master er cylinders 2. Br Brak ake e pe peda dals ls 3. Differ Different ential ial loc lock k pedal
The machine contains two master cylinders (1), one for each brake pedal (2). The master cylinders can be removed from the machine from inside the operator's compartment. Due to a design design change, the brake cylinders no longer have to be removed before removing the cab as required on the "C" Series.
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AWD FRONT AXLE LEFT STEER KNUCKLE HOUSING RING GEAR
KING PINS
BEVEL GEAR
DIFFERENTIAL
PLANET GEAR
SUN GEAR AND SHAFT LEFT DRIVE JOINT
LEFT DRIVE PINION GEAR AXLE AND SHAFT
39
• AWD AWD axl axle e components
The AWD AWD axle is equipped with a conventional bevel and pinion gear differential. The final drive consists of an outboard planetary gear arrangement in each wheel hub.
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1
2 3
40
• AWD fro front nt axle: axle: 1. Seal Sealed ed an and d lubricated pin 2. Ste Steeri ering ng cyl cylin inder der 3. Dr Drai ain n plu plug g
AWD axle is available as an option o ption to replace the standard axle. The axle is pendulum mounted. The pin (1) is permanently sealed sealed and lubricated. The steering cylinder (2) is is mounted to the front of the axle. The standard axle is is also permanently sealed and lubricated. The steering cylinder is mounted to the rear of the axle.
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416D CENTER PIVOT BACKHOE LOADER HYDRAULIC SYSTEM PUMP
TANK END COVER E-STICK COOLER
STICK BUCKET
SMU
BACK FLOW CHECK VALVE
SWING BOOM AUX INLET MANIFOLD
S T E E R
RIGHT STABILIZER LEFT STABILIZER
LEVER
MANIFOLD
LEVER
L I F T
T I L T
A U X
41
STEERING AND IMPLEMENT HYDRAULIC SYSTEMS • 416D 416D hydrau hydraulic lic system: - Cent Center er pivot pivot - Mech Mechanica anicall cont controls rols
The "D" Series backhoe hydraulic systems incorporate many of the improvements made to late production "C" Series. The illustration represents the 416D steering and implement hydraulic system. The steering and implement pump, the pump control and most of the implement control valves function essentially the same. The biggest difference to the implement valves is that on some mode ls they are pilot operated. Also, on some models the operating pressures have also also been increased. On the "D" Series, the stabilizer valves are pilot controlled and are of a different design from previous backhoe loader stabilizer valves.
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The steering system features dynamic signal bleed as did the late production "C" Series. With the dynamic bleed and the steering in HOLD, the steering priority spool bleeds oil through the steering metering unit (SMU) signal line and SMU back to the the tank. When the steering wheel is turned, this signal bleed oil shifts the priority spool to direct pump supply oil to the SMU resulting in faster steering response than systems without dynamic bleed. The hydraulic tank has also been redesigned. An expansion tank is no longer required. The backflow check valve has been relocated. The valve now restricts restricts return flow from all implement implement valve groups. On previous backhoes, the valve only worked with with the backhoe valve group. The valve assists in preventing cylinder voiding. The check valve does not affect return oil from the SMU. The other major difference in the hydraulic system is the signal network routing, which is referred referred to as "reverse signal path." The signal network will be described later in this presentation. NOTE: The colors on the hydraulic schematics and cross-sectional views shown throughout this presentation denote various pressures within the system. The legend of color codes is as follows:
R ed
- pump supply pressure
Red Re d and and whi white te st stri ripe pess
- red reduc uced ed pu pump mp su supp pply ly pr pres essu sure re,, circ circui uitt pressure or load sensing pressure
Red hatch
- further reduced pump supply pressure, circuit pressure or load sensing pressure
Pink
- lowest pump supply pressure, circuit pressure or load sensing pressure
Orange
- signal or pilot pressure
Orange and white white stri stripes pes - a lower signal or pilot pilot press pressure ure Orange hatch
- further reduced signal pressure
Green
- line open to the tank
Blue
- blocked oil
Yellow
- moving part or active valve envelope.
For metering situations more than one envelope may be highlighted in yellow.
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424D / 428D / 438D SIDE SHIFT BACKHOE LOADERS HYDRAULIC SYSTEM SIDESHIFT LOCK PISTONS PUMP TANK
END COVER E-STICK STICK
COOLER
BUCKET BACK FLOW CHECK VALVE
SWING BOOM
SMU
AUX INLET MANIFOLD
S T E E R
SHUTOFF
RIGHT STABILIZER LEFT STABILIZER MANIFOLD
L I F T
T I L T
A U X
LEVER LEVER
42
• 424D, 428D and 438D hydraulic system: - Side Sideshif shiftt machines - Mech Mechanica anicall cont controls rols
The 424D, 428D and 438D sideshift machines have similar components as the center pivot machines. The sideshift machines are equipped with sideshift lock pistons. The 424D is not available with two loader bucket tilt cylinders as shown here. Some countries require a shutoff valve to block the flow of oil to the backhoe valve group when the machine is roaded to prevent unintentional implement movement. Center pivot machines may also be equipped with this feature. The shutoff valve is an option on those machines with mechanical implement imple ment contro controls ls only. only.
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420D / 430D CENTER PIVOT BACKHOE LOADERS HYDRAULIC SYSTEM PARALLEL LIFT PUMP TANK END COVER E-STICK STICK BUCKET SWING BOOM AUX INLET MANIFOLD
P A T T E R N C H A N G E R
J O Y S T I C K
COOLER SMU
BACK FLOW CHECK VALVE
J O Y S T I C K
JOYSTICK
RIGHT STABILIZER LEFT STABILIZER
LEVER
MANIFOLD
LEVER
S T E E R
PILOT SHUTOFF
L I F T
T I L T
A U X
RIDE CONTROL
43
• 420D 420D and and 430 430D D hydraulic system: - Cent Center er pivot pivot machines
The backhoe backhoe valves valves on the 420D 420D and 430D are pilot pilot operated operated.. If the the machine is equipped with with IT linkage, as shown, then then the loader valves are also pilot operated. With pilot operated machines a pilot accumulator is used to provide dead engine lowering capability for a limited time after engine shutdown.
- Pilo Pilott controls controls
These machines ship with the excavator control control pattern. Machines can be ordered with the standard backhoe control pattern or ordered with an optional pattern changer valve. If the machine is equipped with the single tilt cylinder bucket, the loader valves are operated through mechanical linkage instead of a pilot joystick. The pilot shutoff valve blocks the oil from the joysticks to prevent movement of an implement. The shutoff valve eliminates eliminates the need of the optional hydraulic shutoff valve available on machines with mechanical controls only o nly..
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432D / 442D SIDESHIFT BACKHOE LOADERS HYDRAULIC SYSTEM PARALLEL LIFT SIDESHIFT LOCK CYLINDERS
PUMP
TANK END COVER E-STICK STICK BUCKET SWING BOOM AUX INLET MANIFOLD
RIGHT STABILIZER LEFT STABILIZER MANIFOLD
P A T T E R N C H A N G E R
J O Y S T I C K
COOLER
SMU
BACK FLOW CHECK VALVE
J O Y S T I C K
JOYSTICK
S T E E R
LEVER LEVER
PILOT SHUTOFF
L I F T
T I L T
A U X
RIDE CONTROL
44
• 432D 432D and and 442 442D D hydraulic system: - Side Sideshif shiftt machines - Pilo Pilott controls controls
The backhoe backhoe valves valves on on the 432D 432D and 442D are pilot pilot operate operated. d. The loader loader valves are also pilot operated since the standard version of these models feature the IT linkage. The single tilt cylinder bucket is optional. With this option the loader valves are operated through mechanical linkage. Ride control is an option that is available ava ilable for all "D" Series backhoes. Hose routing and the system design has changed from the "C" Series.
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"D" SERIES BACKHOE LOADER SIGNAL NETWORK MECHANICAL CONTROLLED LOADER VALVES PUMP CONTROL VALVE
BACKHOE SECTION AUX
BOOM
SWING
BUCKET
STICK
E-STICK
ORIFICE
TORQUE LIMITER LEFT RIGHT STABILIZER STABILIZER
CONNECTED TO SWASHPLATE LOADER AUX.
LOADER TILT
LOADER LIFT
SMU
PRIMARY RESOLVER SECONDARY RESOLVER LOADER SECTION
45
• Sign Signal al netw network: ork: - Rever Reverse se signal signal path - Affect Affects s resolver resolver troubleshooting - Orif Orificed iced steering steering resolver - Orif Orifices ices in loader loader primary resolvers
On most generations of backhoes, the signal line was routed from the backhoe section, to the loader section and then to the pump. Late production "C" Series had a variation from this with a signal line from the backhoe section and a signal line from the loader section being connected to a tee which was equipped with with a resolver. resolver. The highest resolved signal between the two valve sections then flows to the pump. With the "D" Series, the last resolver in the network is in the loader auxiliary circuit. The signal flows from the loader section, to the stabilizer section, to the backhoe section, before going to the pump control valve. This routing is reverse of previous backhoe signal networks. Resolver troubleshooting procedures are affected affected by this change. A secondary resolver problem in the loader section will no longer have an affect on the backhoe section.
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The orifice in the steering resolver in the loader section results in a larger pressure differential across each loader resolver orifice when a loader implement is activated and the torque limiter opens, as compared to a backhoe implement. This difference in pressure results in a reduced signal to the torque limiter and pump compensator. This action provides for lower pump flow to the loader section for a given circuit pressure when the torque limiter opens, which results in a lower available torque for the loader section than what is available for the backhoe section. This change was done to further improve loader and backhoe performance. Backhoe implements (except for the auxiliary aux iliary circuits) do not have orifices in their primary resolvers and are not affected by the orifice in the steering resolver resolver.. An additional orifice was added between the backhoe valve section and the orifice in the torque limiter for the "D" Series backhoe to further improve machine performance.
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"D" SERIES BACKHOE LOADER SIGNAL NETWORK PILOT CONTROLLED LOADER VALVES PUMP CONTROL VALVE
BACKHOE SECTION PRIMARY RESOLVER
AUX
BOOM
SWING
BUCKET
STICK
E-STICK
ORIFICE
TORQUE LIMITER CONNECTED TO SWASHPLATE
SECONDARY RESOLVER
LOADER AUX.
LIFT PILOT VALVE
LOADER TILT
LEFT RIGHT STABILIZER STABILIZER LOADER LIFT
SMU
LOADER SECTION PILOT OIL
46
• Sign Signal al netw network: ork: - Pilot operated loader valves
On machines with pilot operated loader valves, the pilot valve for the loader lift circuit is also part of the signal network. The lift pilot valve directs some pilot oil through the resolver network to upstroke the pump p ump when the loader is in FLOAT. FLOAT. This pilot signal through the signal network causes the pump to increase pump standby pressure to make sure that pilot system pressure remains high enough to hold the lift spool in the FLOAT FLOAT position. NOTE: Since the maximum pilot pressure is limited, the pump receives a virtually fixed signal from the pilot system when the lift spool is shifted to FLOAT FLOAT. This increase in pump supply and signal pressure can be checked at the pump outlet test fitting and the signal test fitting. There is no recommended specification or test for this.
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1 2
4 3
47
• Hydrau Hydraulic lic system system components: 1. Hy Hydr drau auli lic c tank tank 2. Si Sigh ghtt ga gaug uge e 3. Steeri Steering ng Met Meteri ering ng Unit (SMU) 4. Dr Drai ain n tub tube e
The hydraulic tank (1) is located between the engine and the cab. With the relocation of the brake master cylinders, the hydraulic tank was redesigned for increased capacity. capacity. With the increase in capacity the overflow or expansion tank is no longer required.
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6
1
3 4
2
5
48
• Hydrau Hydraulic lic system system components: 1. Hyd Hydrau raulic lic fil filter ter 2. Stee Steeri ring ng an and d implement pump 3. Pu Pump mp con contro troll valve valve 4. Signal Signal pr press essure ure test fitting 5. Lo Loade aderr valv valve e grou group p 6. Back Back flo flow w che check ck valve
• Pump Pump and and system system tests
In the pump control valve (3) are two spools. The flow compensator (margin spool) regulates output flow in response to the load signal received through the signal signal network. The flow supplied by the pump will will be the amount of flow required to keep supply pressure at a fixed value above the signal pressure. pressure. The difference between supply pressure and the signal pressure is called "margin pressure." The flow compensator also controls low pressure standby pressure. The pressure cutoff spool in the pump control valve limits maximum system pressure and serves as the relief valve for the system. The back flow check valve (6) is part of the fitting just before the hydraulic filter (1). The check valve helps reduce reduce cylinder cavitation. Before performing any pump tests or making adjustments a djustments to the pump control valve, measure and record the machine cycle times. If the cycle times are within specification, checking low pressure standby or margin pressure may not be required unless the system is overheating. Cycle time checks will also indicate if all or some of the implements in the system are operating within specification.
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This information can be helpful in determining if the pump or the implement is at fault. If all cycle times are too slow, slow, margin pressure and low pressure standby may be set set too low. low. If the machine is too responsive, the margin pressure and low pressure standby may be set too high. The pump supply pressure test fitting (not shown) can be used to check maximum system pressure or low pressure standby. standby. The fitting can be accessed from below the operator's compartment. Use the signal pressure test fitting (4) to check the signal pressure or the maximum steering pressure. pressure. Signal pressure is is compared to pump supply pressure to determine the margin pressure. All return oil from the implements and steering flows back to the filter through the backflow check valve. Due to the dynamic bleed steering, low pressure standby is over 700 kPa (100 psi) higher than on most "C" Series backhoes. NOTE: Due to the signal signal pressure pressure limiter, limiter, the steering circuit circuit is commonly used to check margin pressure because the steering circuit pressure is below maximum system pressure. Engineering is recommending a slightly different procedure for checking margin pressu pressure re on "D" machine machines. s. The latest latest recommendation is to lock the boom and move the boom lever about one third travel in the DOWN position. If Standby Pressure is adjusted to about 3100 kPa (450 psi) or slightly higher, the need to adjust a check margin pressure may not be necessary. Also, on the "D" Series, engineering is suggesting that circuit and system stall pressures be checked at the signal pressure test fitting. By doing this the confusion related to checking circuits with lower pressure settings than the pressure cutoff on the pump may be eliminated. For circuits with higher line relief settings than the pressure cutoff, the pressures read at either test port should be the same.
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49
• Hydrau Hydraulic lic system system components: - Torq Torque ue limiter limiter (arrow)
A torque limiter (arrow) (arrow) is used to control the pump. The torque limiter will reduce maximum pump flow available as a s pressures increase to prevent engine stall. The torque limiter provides improved hydraulic system performance with less engine horsepower horsepower.. The torque limiter is adjustable. adjustable. Before making adjustment to the torque limiter, make sure low idle is set correctly correctly.. NOTE: A quick check to make sure sure the torque limiter is operating correctly on single tilt cylinder machines, is to operate the machine at low idle. With the machine at normal operating temperatures, apply the service brakes and select SECOND FORWARD. FORWARD. Turn on air conditioner (if equipped) and accessories. Raise and rack back the bucket. If the engine stalls, the torque limiter may need to be adjusted. For dual tilt cylinder machines, follow the same steps, except stall the bucket in the dump position, instead of racking back. For more precise adjustment of the torque limiter follow the procedures in the service manual. A torque converter stall test should also be done before adjusting the torque torque limiter. limiter. The engine may not be performing correctly.
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STEERING AND IMPLEMENT PUMP LOW PRESSURE STANDBY / DYNAMIC SIGNAL BLEED
TORQUE LIMITER BLEED SIGNAL
FLOW COMPENSATOR
PUMP OUTPUT
PRESSURE CUTOFF
50
Steering and Implement Pump Operation • LOW LOW PR PRES ESSU SURE RE STANDBY: - With dynami dynamic c signal bleed
With all implements in HOLD, the steering priority valve bleeds some supply oil through a dynamic bleed orifice back to the tank through the SMU. This oil flow creates a low pressure signal which is sensed at the pump compensator. The LOW PRESSURE STANDBY STANDBY reading will be higher on "D" Series machines equipped with a dynamic signal bleed steering system than on previous backhoes without this feature. The spring setting of the torque limiter changes with the angle of the swashplate. As shown here, at minimum angle, the setting is at maximum. As the swashplate angle is increased, the spring setting is reduced.
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SIGNAL
STEERING AND IMPLEMENT PUMP CONSTANT FLOW
PUMP OUTPUT
FLOW COMPENSATOR
PRESSURE CUTOFF
51
• CONS CONSTAN TANT T FLO FLOW: W: - Sign Signal al pressure pressure plus spring equals system pressure - Swas Swashpla hplate te at constant angle
The pump will will UPSTROKE UPSTROKE or DESTROKE DESTROKE to match changes changes in flow flow requirements. When pump flow matches system needs the pump supply pressure equals the sum of the load pressure pressure plus the margin margin spring pressure. The margin spool is in a metering position and the system is stabilized. CONSTANT FLOW is maintained until there is a change in system flow requirements. The difference between the signal pressure and the pump supply pressure is the value of the margin spring.
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TORQUE LIMITER CONTROL FLOW COMPENSATOR CONTROL BACKHOE LOADER
FLOW (Q)
PRESSURE (P)
52
• Pressure/ Pressure/Flo Flow w (P-Q) (P-Q) Curve: - Swee Sweeping ping curve shows torque limiter control
This illustration shows a Pressure/Flow (P-Q) Curve Chart for the steering and implement pump. The purpose of the chart is to show how the torque limiter affects the maximum flow rate for the loader and backhoe sections when the torque limiter opens. The sweeping curves show where the torque limiter has control over the pump flow. flow. The torque limiter destrokes the pump as the system pressure increases. The rate of destroke closely follows the torque curve of the engine. While on the torque curve, if the system pressure decreases, the torque limiter control will UPSTROKE the pump. The flow compensator spool regulates pump flow whe n system pressure and flow requirements are below the curves. This is the area shown shown in yellow.
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STMG 746 STMG 10/02
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NOTE: When the updated "C" Series was introduced, the torque limiter was being promoted promoted as having "dual settings." This was not the case. The torque limiter has one physical setting. Due to the orifices as discussed earlier, the torque limiter responds as if it had two different settings.
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SIGNAL
STEERING AND IMPLEMENT PUMP TORQUE LIMITER OPEN
TORQUE LIMITER PUMP OUTPUT
FLOW COMPENSATOR
PRESSURE CUTOFF
53
• Torq Torque ue limiter limiter OPE OPEN: N: - Press Pressure ure setting setting varies with swashplate angle - Press Pressure ure drop across orifice - Reduction in signal signal pressure to flow compensator
The torque limiter monitors the pump swashplate angle and the pump signal pressure. The pressure setting of the torque limiter varies varies with the swashplate angle: the greater the swashplate angle, the lower the pressure pressure setting. For example, if the pump is at full stroke, the torque limiter will begin to destroke the pump when system pressure increases above 15180 kPa (2200 psi). As system pressure pressure continues to increase, the pump flow flow is further reduced. The allowable pump displacement is inversely proportional to the pump discharge pressure: the higher the pressure, the less pump flow available.
- Pump destr destrokes okes - Inp Input ut torque torque is maintained
When the torque limiter setting is reached, the torque limiter opens, directing some of the signal oil to the tank. A pressure drop occurs across the orifice, resulting in a slight loss of the actual signal pressure. The flow compensator spool will move up, allowing supply oil to the large actuator piston. The pump will will then destroke.
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SIGNAL
STEERING AND IMPLEMENT PUMP TORQUE LIMITER CLOSED
TORQUE LIMITER PUMP OUTPUT
FLOW COMPENSATOR
PRESSURE CUTOFF
54
• Torq Torque ue limiter limiter OPE OPEN: N: - Stays open when hydraulic demand at or above torque curve - Two different torque curves
The torque limiter remains open and works with the flow compensator for as long as the conditions for the hydraulic demand are "at" or "above" the torque curve. If the load conditions are demanding a certain pressure, the operator is requesting a certain flow by positioning the valve stem and these conditions are "at" or "above" the torque curve, the torque limiter is open. In summary, summary, full pump supply pressure pressure is always available. However, flow is regulated to maintain a maximum input inpu t torque from the engine. Due to the additional orifices in the loader resolvers, the torque limiter in effect has two different different torque curves: one for the loader and one for the the backhoe.
• Torqu Torque e limiter limiter CLOSED: - Flo Flow w compensator compensator controls swashplate
When the hydraulic demand falls below the conditions stated above, the torque limiter closes and the flow compensator then has control over the pump swashplate to regulate pump flow to meet the required system pressure and flow demands.
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4
3 2 1
55
Loader Valve Groups and Steering System • Loader Loader valve valve group group components: 1. Inlet Inlet mani manifol fold d and and steering priority valve 2. Loade Loaderr lift lift con contro troll valve 3. Til Tiltt con contro troll valv valve e 4. Au Auxi xili liar ary y valve valve
The loader section consists of an inlet manifold (1) with a steering priority valve, a loader lift control valve (2), a tilt control valve (3) and an optional auxiliary valve (4). The implement valves shown are pilot operated. ope rated.
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STEERING PRIORITY VALVE DYNAMIC SIGNAL BLEED FLOW TO IMPLEMENTS
FLOW TO SMU
TO SMU TO TANK
TO SMU TO TANK
DYNAMIC BLEED ORIFICE
DYNAMIC BLEED ORIFICE
PRIORITY SPOOL FROM PREVIOUS VALVE
FROM PREVIOUS VALVE SPRING FROM PUMP
TO LOADER VALVES
SIGNAL PRESSURE LIMITER
TO LOADER VALVES
FROM PUMP
RESOLVER TO SMU
TO SMU TO PUMP
TO PUMP
56
• Steering Steering prior priority ity valve valve operation: - With dynami dynamic c signal bleed orifice - Flo Flow w to implements implements
The loader inlet manifold and steering priority valve are shown in two different conditions. One condition shows flow to the implements and the other shows flow to the SMU. Before the engine is started, the spring holds the priority spool to the left. When the engine is started, the flow from the pump is directed to the priority valve. With the spool to the the left, the pump supply oil is directed to the SMU. As the SMU passage fills, fills, oil also enters the axial-drilled hole in the priority spool and flows to the left end of the spool. As pressure builds on the left end, the spool starts to move to the right, against the force of the spring. spring. The spool begins to restrict restrict the oil flow to the SMU supply passage as the spool continues to move to the right. right. Oil restricted by the priority spool from entering the SMU supply passage flows to the loader implement valves.
➥
STMG 746 STMG 10/02
- Dyna Dynamic mic bleed bleed orifice
- 82 -
The priority spool never completely blocks the flow of oil to the SMU supply passage. A small amount of oil is allowed to flow through through the dynamic bleed orifice to the priority spool spring cavity where it becomes signal oil. Signal oil flows from the spring cavity through the SMU signal line to the SMU, where the oil flows flows to the tank. This action causes the priority priority spool to meter oil continuously to the SMU supply passage to maintain a predetermined pressure in the SMU supply passage. This pressure provides instantaneous steering response when the steering is activated. The metering action also reduces spool travel when steering is required, which results in faster steering response. With all implements in HOLD in this closed-center system, this signal oil is sensed at the pump control valve va lve resulting in an increase in the LOW PRESSURE PRESSU RE ST STANDBY ANDBY setti setting. ng. If flow is not needed for steering and an implement valve in the loader section is activated, the priority valve will direct most of the supply oil to the loader implement circuits.
- Oil flow flow to to SMU
When the steering wheel is turned, more flow is needed at the SMU; this causes a momentary drop in pressure in the SMU supply passage. Pressure on the left side of the priority spool is also redu ced. The signal bleed pressure oil in the spring cavity and the priority spring move the spool to the left, left, blocking flow to the implements. implements. As the pump flow increases and supply oil enters the SMU passage, pressure increases increases in the SMU passage and on the left end of the priority priority spool. As the forces on both ends of the spool equalize, the spool moves to a position which enables it to maintain the flow requirements requ irements of the steering circuit. As previously stated, the signal oil originates in the priority valve spring cavity.. From there, the signal goes to the resolver and to the SMU. At cavity the SMU, the signal line is connected connec ted to the pressurized cylinder port (left or right). From the resolver, resolver, the signal oil flows flows to the pump control valve. The pump then increases flow to to meet the steering system system flow requirements. Because the priority spool gives preference to the SMU supply circuit, flow may be blocked or metered to the loader implement valves.
➥
STMG 746 STMG 10/02
- Sign Signal al pressure pressure limiter valve
- 83 -
A signal pressure limiter valve limits the steering signal to protect the various steering components. When the signal pressure reaches a predetermined limit, the poppet in the signal pressure limiter moves to the right, opening a passage to the tank. The spool moves back to the right and blocks flow from going to the SMU.
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STEERING CIRCUIT TURN
STEERING PRIORITY VALVE
FROM PREVIOUS VALVE
TO LOADER VALVES
MAKEUP VALVE
PUMP SUPPLY
CHECK VALVE TO PUMP COMPENSATOR
STEERING METERING UNIT
57
• Steer Steering ing circu circuit: it: - Sign Signal al oil sent sent to SMU from prior priority ity valve - Also enters enters signal signal network - SMU dire directs cts oil oil to steering cylinder
• Check Check valve valve preven prevents ts "kickback" • Makeup Makeup val valve ve provides steering capability if the engine stops
This illustration shows shows the steering system during a TURN. Signal oil is sent from the steering priority valve past the che ck valve to the SMU where the oil combines with the the cylinder oil. The pressure in the SMU signal line is limited limited to the steering cylinder port pressure. The signal oil also enters the the signal network and flows to the pump control valve. The pump then increases flow to meet the steering system flow requirements. Oil from the pump flows past the steering priority valve to the SMU and to the double rod steering cylinder. cylinder. When the machine makes a TURN, the SMU directs oil to the left side of the cylinder piston and opens the right side to the tank. A TURN in the other direction operates inversely. inversely. The check valve in the pump supply line between the SMU and the loader valve inlet manifold prevents steering "kickback" due to an external force. The makeup valve provides steering capability when the engine is not running by allowing oil to recirculate between the SMU and the steering cylinder when the steering wheel is turned.
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"D" SERIES MECHANICALLY CONTROLLED LOADER VALVES PUMP
TANK
END COVER E-STICK STICK
COOLER
BUCKET BACKFLOW CHECK VALVE
SWING BOOM
SMU
AUX INLET MANIFOLD
S T E E R
RIGHT STABILIZER LEFT STABILIZER
LEVER
MANIFOLD
LEVER
L I F T
T I L T
A U X
58
• Loade Loaderr valve valve operation: - Mech Mechanica anicall cont controls rols
The following seven illustrations will cover the remaining valves in the loader valve group that are all mechanically operated. All of the valves in the loader valve group are closed-center and pressure compensated. INSTRUCTOR NOTE: NOTE: Components shown in yellow are shown on block diagrams throughout throughout this presentation. presentation. These diagrams are are to be used to introduce different sections of the hydraulic system discussed in this presentation.
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LOADER LIFT CONTROL VALVE
FROM PREVIOUS VALVE
HOLD
HEAD END
ROD END
PLUG
ADVANCE SIGNAL PASSAGE TO STEERING VALVE
BALL DETENT FLOW CONTROL VALVE FROM PUMP
59
• Loader Loader lift lift contro controll valve in HOLD: - Adva Advance nce signal signal passage for loader RAISE
The loader lift control valve has a flow control spool and a makeup valve on the rod end work port. The main control spool also has an advance signal passage to help raise the loader. The loader lift control lever has four positions: RAISE, HOLD, LOWER and FLOAT.
- Four position spool - Mech Mechanica anicall ball detent for FLOAT
INSTRUCTOR NOTE: For a detailed description of implement valve operation used in the "D" Series, refer to STMG 630 "416B 438B Backhoe Loaders–Steering and Implement Hydraulic System" (Form SESV1630).
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FROM PREVIOUS VALVE
416D AND 424D LOADER TILT CONTROL VALVE HOLD
HEAD END
LINE RELIEF AND MAKEUP VALVE
ROD END
TO NEXT VALVE
SOLENOID DETENT ADVANCE SIGNAL PASSAGE
FROM PUMP
FLOW CONTROL VALVE
60
• 416D and 424D tilt control valve in HOLD: - Adva Advance nce signal signal passage for RACK BACK - Three position spool - Magn Magnetic etic detent detent for "return to dig" feature
The 416D and 424D tilt control valve is used to control a single tilt cylinder. The tilt control valve has a flow control spool and a pilot operated makeup and line relief valve for each work port. The main control spool has an advance signal signal passage passage for the TILT TILT BACK or RACK BACK function. function. The control spool has a magnetic magne tic detent (solenoid) that is part of the "return to dig" feature. The loader tilt control control lever has three positions: RACK BACK, HOLD and DUMP DUMP..
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428D AND 438D LOADER TILT CONTROL VALVE FOR PARALLEL LIFT HOLD FROM PREVIOUS VALVE ROD END
HEAD END
LINE RELIEF AND MAKEUP VALVE
TO LIFT VALVE
SOLENOID DETENT FLOW CONTROL VALVE FROM PUMP
61
• 428D and 438D tilt valve for parallel lift in HOLD: - Four position spool - Magn Magnetic etic detent detent for "return to dig" feature
The 428D and 438D tilt control valve is used to control two tilt cylinders. The loader parallel tilt tilt control lever has four positions: positions: RACK BACK, HOLD, DUMP and REGENERATIVE DUMP. The valve has a magnetic detent for "return to dig."
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428D AND 438 LOADER TILT CONTROL VALVE FOR PARALLEL LIFT REGENERATIVE DUMP FROM PREVIOUS VALVE
ROD END
HEAD END
LINE RELIEF AND MAKEUP VALVE
TO LIFT VALVE
SOLENOID DETENT FLOW CONTROL VALVE FROM PUMP
62
• Parall Parallel el lift lift in REGENERATIVE DUMP
The force of gravity tends to cause ca use implements to lower faster than the hydraulic pump and makeup valves can fill the cylinders. A "REGENERATIVE "REGENERA TIVE DUMP" position can reduce this tendency. tende ncy. Due to the lands of the tilt valve, return oil from Port "B" cannot go g o to the tank. The return oil from the the implement is directed through through the bridge passage to Port "A" when the control spool is shifted to the REGENERATIVE REGENERA TIVE DUMP position. This position allows the bucket to be powered down by pump flow. This action prevents cylinder cavitation and causes the bucket to dump faster. NOTE: The line relief valve settings are set lower than maximum system pressure on machines equipped with parallel lift.
STMG 746 STMG 10/02
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416D AND 424D AUXILIARY CONTROL VALVE HOLD
LINE RELIEF AND MAKEUP VALVE
PORT A
PORT B
TO NEXT VALVE
FLOW CONTROL VALVE
FROM PUMP
63
• 416D and 424D 424D loade loader r auxiliary control valve in HOLD: - Used for for MP bucket bucket
The 416D and 424D loader auxiliary valve is typically used for the MultiPurpose (MP) Bucket. The loader auxiliary control valve has a flow control spool and a pilot operated makeup and line relief valve for the rod end work port.
- Three position spool
The loader tilt control lever has three positions: OPEN, HOLD and CLOSE.
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428D AND 438D AUXILIARY CONTROL VALVE FOR PARALLEL LIFT HOLD
RESOLVERS
LINE RELIEF AND MAKEUP VALVE
PORT A
PORT B
TO NEXT VALVE
SOLENOID DETENT
CONTROL SPOOL
FLOW CONTROL VALVE
FROM PUMP
64
• 428D 428D and and 438 438D D parallel lift loader auxiliary control valve in HOLD: - Three position spool - Lin Line e relief relief and makeup valve
The 428D and 438D loader auxiliary control valve provides more versatility than the 416D and 428D loader auxiliary control valve. The loader auxiliary control valve has a flow control spool and a pilot operated makeup and line relief valve for the rod end work port. The auxiliary control lever has three positions. A solenoid detent is also used for applications requiring c ontinuous flow. flow.
- Sole Solenoi noid d detent
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1
2
65
• Single Single tilt tilt cylinder cylinder loader: 1. Mi Micr cros oswi witc tch h 2. Lo Loade aderr lin linkag kage e arm arm
The loader linkage arm (2) has been redesigned for improved reliability. The microswitch (1) rides along a cam machined into the bucket link. The switch works with a solenoid on the bucket control valve to provide the "return to dig" feature.
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"D" SERIES PILOT CONTROLLED LOADER VALVES PUMP TANK END COVER E-STICK STICK BUCKET SWING BOOM AUX INLET MANIFOLD
RIGHT STABILIZER LEFT STABILIZER MANIFOLD
P A T T E R N C H A N G E R
J O Y S T I C K
COOLER SMU
BACKFLOW CHECK VALVE
J O Y S T I C K
JOYSTICK
S T E E R
LEVER LEVER
PILOT SHUTOFF
L I F T
T I L T
A U X
RIDE CONTROL
66
• Loade Loaderr valve valve operation: - Pilo Pilott controls controls
The following 14 illustrations will cover the valves in the loader valve group that are pilot operated along with their related components. The internal components of the pilot controlled implement valve are basically the same as the mechanically controlled implement control valve except for the difference in how the valves are controlled. All of the valves are closed-center and pressure compensated.
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LOADER LIFT CONTROL VALVE FROM PREVIOUS VALVE
RESOLVERS
HOLD
ADVANCE SIGNAL PASSAGE
ROD END
HEAD END
TO NEXT VALVE
CONTROL SPOOL
PILOT PASSAGE
FLOW CONTROL VALVE
FROM PUMP
67
• Loader Loader lift lift contro controll valve in HOLD: - Adva Advance nce signal signal passage for loader RAISE
The loader lift control valve has a flow control spool and a makeup valve on the rod end work port. The main control spool also has an advance signal passage to help raise the loader. The loader lift control lever has four positions: RAISE, HOLD, LOWER and FLOAT.
- Four position spool
Pilot oil is directed to either end of the spool to shift the valve.
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LOADER LIFT CONTROL VALVE FROM PREVIOUS VALVE
RESOLVERS
FLOAT
ADVANCE SIGNAL PASSAGE
ROD END
HEAD END TANK PASSAGE
TO NEXT VALVE
CONTROL SPOOL
PILOT PASSAGE
FLOW CONTROL VALVE
FROM PUMP
68
• Loader Loader lift lift valve valve in FLOAT
For the FLOAT position, higher pilot pressure acting on the right end of the control spool moves the spool further to the left than for LOWER. Both workports are open to the tank through passages in the valve. A solenoid in the joystick maintains the spool in FLOAT FLOAT position until the operator shifts the spool to a different position. FLOAT FLOA T is used for "backdragging."
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LOADER TILT CONTROL VALVE FROM PREVIOUS VALVE
HOLD
ROD END
RESOLVERS
HEAD END
LINE RELIEF AND MAKEUP VALVE
TO NEXT VALVE
CONTROL SPOOL
PILOT PASSAGE
FLOW CONTROL VALVE
FROM PUMP
69
• Tilt cont control rol valve valve in HOLD: - Used with with dual dual tilt cylinders - Four position spool
This illustration shows the pilot operated tilt control valve used with the dual tilt cylinder configuration. The tilt control valve has a flow control spool and a pilot operated makeup and line relief valve for each work port. The main control spool has an advance signal signal passage passage for the TILT TILT BACK or RACK BACK function. function. The pilot joystick has a magnetic detent de tent (solenoid) that is part of the "return to dig" feature. The loader tilt control control lever has four positions: RACK BACK, HOLD, DUMP and REGENERATIVE REGENERATIVE DUMP DUMP..
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LOADER TILT CONTROL VALVE FROM PREVIOUS VALVE
REGENERATIVE DUMP
PORT A
RESOLVERS
PORT B LINE RELIEF AND MAKEUP VALVE
TO NEXT VALVE
CONTROL SPOOL
PILOT PASSAGE FLOW CONTROL VALVE
FROM PUMP
70
• Parall Parallel el lift lift in REGENERATIVE DUMP
The force of gravity tends to cause ca use implements to lower faster than the hydraulic pump and makeup valves can fill the cylinders. A "REGENERATIVE "REGENERA TIVE DUMP" position can reduce this tendency. tende ncy. Due to the lands of the tilt valve, return oil from Port "B" cannot go g o to the tank. The return oil from the the implement is instead directed directed through the bridge passage to Port "A" when the control spool is shifted to the REGENERATIVE DUMP position. This position allows the bucket to be powered down by pump flow. flow. This action prevents cylinder cavitation and causes the bucket to dump faster.
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FROM LOADER JOYSTICK
RESOLVERS
LOADER AUXILIARY CONTROL VALVE HOLD
LINE RELIEF AND MAKEUP VALVE
PORT A
PORT B
CONTROL SPOOL TO NEXT VALVE
AUXILIARY HYDRAULIC SOLENOID VALVE NO. 2
FLOW CONTROL VALVE
FROM PUMP
AUXILIARY HYDRAULIC SOLENOID VALVE NO. 1
71
• Loader Loader auxil auxiliary iary control valve in HOLD: - Solenoid Solenoids s controlled by the Auxiliary Control Module (ECM)
The loader auxiliary control valve is equipped with two proportional solenoids. The solenoids direct pilot oil to shift the the control spool. The solenoids are controlled by the Auxiliary Control Module (ECM).
STMG 746 STMG 10/02
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LOADER AUXILIARY CONTROL VALVE
FROM LOADER JOYSTICK
HOLD
RESOLVERS
PORT A
LINE RELIEF AND MAKEUP VALVE
PORT B
CONTROL SPOOL AUXILIARY HYDRAULIC SOLENOID NO. 1
TO NEXT VALVE
AUXILIARY HYDRAULIC SOLENOID NO. 2
REVERSE DIRECTION DISABLE JUMPER
FROM PUMP
FLOW CONTROL VALVE E540 PK
E540 PK
E544 GN
E543 WH
PILOT OIL FROM END COVER
TO KEY SWITCH
G943 BU
2
QUICK COUPLER SWITCH 1 3
5
4 6
JOYSTICK
163 WH N997 WH
AUXILIARY CONTROL ECM
203 BK 585 YL
203 BK
PILOT LOADER HANDLE CONTROL
586 BR M968 BU H833 PU 779 WH 163 WH
CONTINUOUS FLOW SWITCH
QUICK COUPLER SOLENOID VALVE
TO KEY SWITCH
72
• Loader Loader auxil auxiliary iary circuit: - Quic Quick k coupler coupler switch
The Auxiliary Control ECM receives inputs from the thumb switch on the joystick, the continuous flow switch and the quick coupler switch.
- Con Continu tinuous ous flow switch
The Auxiliary Control ECM senses the position of the quick coupler switch to control the quick coupler solenoid valve. The solenoid valve locks or unlocks the coupler pins.
- Quic Quick k coupler coupler solenoid valve
A manual diverter valve (not shown) mounted on the loader linkage allows oil to and from the coupler pins or to and from an auxiliary aux iliary circuit.
- Auxi Auxiliar liary y Con Control trol ECM
When the coupler pins are unlocked, the coupler pins can be engaged or disengaged with the quick coupler switch. The thumb switch can be used to engage the pins.
- Auxi Auxiliar liary y hydr hydrauli aulic c solenoids
When the coupler switch is moved to the LOCKED position, the Auxiliary Control ECM will de-energize the quick coupler solenoid va lve. The coupler pins are then locked in position.
STMG 746 STMG 10/02
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LOADER AUXILIARY CONTROL VALVE
FROM LOADER JOYSTICK
SHIFT
RESOLVERS
PORT A
LINE RELIEF AND MAKEUP VALVE
PORT B
CONTROL SPOOL AUXILIARY HYDRAULIC SOLENOID NO. 1
TO NEXT VALVE
AUXILIARY HYDRAULIC SOLENOID NO. 2
FROM PUMP
FLOW CONTROL VALVE E540 PK
E540 PK E543 WH
E544 GN
REVERSE DIRECTION DISABLE JUMPER
PILOT OIL FROM END COVER
TO KEY SWITCH
JOYSTICK
G943 BU 163 WH
2
QUICK COUPLER SWITCH 1 3
5
4 6
N997 WH
AUXILIARY CONTROL ECM
203 BK 585 YL
203 BK
PILOT LOADER HANDLE CONTROL
586 BR M968 BU H833 PU
779 WH 163 WH
CONTINUOUS FLOW SWITCH
QUICK COUPLER SOLENOID VALVE
TO KEY SWITCH
73
• Loader Loader auxil auxiliary iary circuit: - Auxi Auxiliar liary y Con Control trol ECM sensed thumb switch position to control auxiliary solenoid - Con Continu tinuous ous flow switch used to maintain flow rate - Rever Reverse se direction direction disable jumper
When the thumb switch on the joystick is moved, the Auxiliary Control ECM senses the position of the thumb switch and send a variable current to one of the proportional solenoids to shift the auxiliary control spool. The current will vary depending on how far the thumb switch is moved. The solenoid directs pilot oil to one end e nd of the control spool. Operation of the flow control spool and resolvers is the same as with other pressure compensated implement control valves used on backhoe loaders. If the operator wants to maintain a fixed flow rate, the continuous flow switch can be pressed momentarily. momentarily. Then release the thumb switch within within one second. When the thumb switch is released, the desired flow rate rate will be maintained until either the thumb switch is moved, the continuous flow switch is pressed again or the quick coupler co upler switch is activated. For some attachments (broom), the reverse direction disable jumper is installed to disable solenoid solenoid No. 1. The auxiliary circuit will now only operate in one direction.
STMG 746 STMG 10/02
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3
2
1
74
• Load Loader er pilot pilot controls: controls: 1. Pi Pilo lott joys joysti tick ck 2. Butt tto ons 3. Th Thum umb b sw swit itch ch
On the loader pilot joystick (1), the yellow y ellow buttons (2) on the control can be used to control an auxiliary function or for AWS. AWS. On the electrical schematic the buttons control the left and right broom angle relays. The thumb switch (3) works with a the Auxiliary Control ECM to vary the current to two proportional solenoids mounted o n the loader auxiliary valve. A switch on the front front of the joystick is used to downshift the transmission or neutralize it depending on how long the switch is held.
STMG 746 STMG 10/02
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75
• Auxiliar Auxiliary y Control Control ECM ECM (arrow)
The Auxiliary Control ECM (arrow) is located below the side console gauge and switch panel. If the machine is equipped with the optional Machine Security System (MSS), the ECM for MSS is attached to the back of the Auxiliary Control ECM.
STMG 746 STMG 10/02
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3
2 1
76
• Load Loader er compon components: ents: 1. Coupl Coupler er cyl cylin inder der guard 2. Div Divert erter er val valve ve lev lever er 3. Revers Reverse e di direc rectio tion n disable harness connector
The diverter valve lever (2) allows the operator to divert flow to an attachment and blocks the oil in the coupler cylinder to lock the attachment to the loader linkage. The cylinder is protected by a guard (1). The reverse direction disable harness connector (3) permits connecting a jumper to disable the No. 1 auxiliary solenoid to allow flow in only one direction. When the jumper (not shown) is installed, the thumb switch on the loader joystick only operates an attachment in one direction. An additional harness connector (not shown) allows the connection of an electrically controlled function to the the front loader. loader. This function is controlled by the two yellow buttons bu ttons shown earlier on the loader joystick.
STMG 746 STMG 10/02
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ACCUMULATOR
ORIFICE
975-WH F748-WH
RIDE CONTROL SWITCH 614-PU
1 2 3 4 5 6
SHUTOFF VALVE
A972-OR 976-OR F739-GN E701-PK
RIDE CONTROL RELAY M969-YL
1 2 134-YL
ORIFICE
PUMP SUPPLY
1 2
SOLENOID
ARC SUPPRESSION
LIFT CYLINDERS
CHECK VALVE
LIFT CONTROL VALVE PUMP SUPPLY
F738-WH
PRESSURE SWITCH FLOW COMPENSATOR
RIDE CONTROL STANDARD TRANSMISSION ON SIGNAL FROM PREVIOUS VALVE TO TANK RESOLVERS
77
• Ride Con Control trol System System:: - Sta Stand ndard ard transmission
• Ride cont control rol switc switch h ON: - Circ Circuit uit grounded grounded through closed pressure switch - Press Pressure ure switch switch senses rod end pressure
This illustration shows a combined electrical/hydraulic schematic of the Ride Control System on machines with with a standard transmission. transmission. The lift control valve is in HOLD and is blocking both the rod and head ends of the cylinder cy linder.. When the key start switch is in the ON position, power is available at the ride control switch through the 614-PU wire an d the switch and dash indicators are illuminated. When the ride control switch switch is in the OFF position, the ride control solenoid is not energized. To energize the coil in the ride control relay the pressure switch must be closed to complete the circuit from the ride control switch. The pressure switch senses the pressure in the line to the rod end of the loader lift cylinder. cylinder. When the pressure in the the rod end of the loader lift lift cylinder is less than the actuation pressure of the pressure switch, the switch closes.
➥
STMG 746 STMG 10/02
- Low pressu pressure, re, switch closes - Rel Relay ay clo closes ses - Ride Ride contr control ol solenoid energized
• Ride cont control rol ON: - Accu Accumula mulator tor and cylinder head ends connected - Accu Accumula mulator tor acts acts as shock absorber over rough terrain • Ride cont control rol OFF: - Sole Solenoi noid d not energized - Orif Orifice ice creates creates restriction between accumulator and cylinders - Preven Prevents ts rapid rapid loss of stored oil - Allo Allows ws accumulator to be recharged • Pre Pressu ssure re switch switch - Preve Prevents nts ride control control from being activated if pressure high
- 105 -
When the pressure switch is closed, the coil in the relay is energized, closing the relay. relay. Power from the ride control switch flows through through the ride control relay to the solenoid. The ride control solenoid is now energized. When the ride control solenoid is energized, pump supply oil flows through the solenoid to unseat the check valve and to shift the shut-off valve. This action connects the head end of the the loader lift cylinders to to the ride control accumulator and the rod end of the loader lift cylinders are open to the tank through the check valve. When the machine is driven over rough terrain with the ride control system ON, the loader lift lift cylinders extend and retract. As the lift cylinders extend, oil displaced from the rod ends of the cylinders open to the tank and oil which is stored in the accumulator flows into the head ends of the cylinders. As the lift cylinders retract, oil displaced displaced from the head ends of the cylinders flows into the accumulator, and oil is drawn from the tank into the rod ends of the cylinders. The accumulator acts as a shock absorber when the cylinders retract, providing a smoother ride. When the ride control system is OFF, the ride control solenoid is not energized. Under this condition, the solenoid drains drains the supply oil to the check valve and the shutoff valve to to the tank. The check valve seats and blocks the passage from the rod ends of the lift cylinders to the tank. The shut-off valve moves down and blocks the flow of oil oil through it. The orifice dampens the closing of the check valve and the shifting of the shut-off valve. The orifice in the line between the accumulator and cylinder head ends prevents the rapid loss of the oil which is stored in the accumulator when the loader arms are lowered. The orifice also allows the the accumulator to be charged, without adversely affecting machine performance when the loader arms are lifted. The pressure switch prevents the ride control relay, and therefore, the ride control solenoid, from energizing if the pressure in the rod e nd of the loader lift cylinder becomes greater than the actuation pressure of the pressure switch. An example of this situation is when the loader arms are used to lift the front wheels off of the ground. If the ride control system was engaged under this circumstance, the machine would fall to the ground.
STMG 746 STMG 10/02
- 106 -
AUTOSHIFT ECM 123-WH
F748-WH
RIDE CONTROL SWITCH 614-PU
1 2 3 4 5 6
ACCUMULATOR
1 2
BATTERY GROUND
21 22 39 37 23 18
R/C AUTO SW TO GND R/C ON SW TO GND SOL RETURN RIDE CNTRL RELAY PRESS SW TO GND R/C ENABLE CMD SW TO BAT
SHUTOFF VALVE
E702-OR 1 2
975-WH F739-GN
A972-OR
976-OR
E701-PK
M969-YL
1 2
RIDE CONTROL RELAY
PUMP SUPPLY
134-YL 1 2
ARC SUPPRESSION
SOLENOID
LIFT CYLINDERS
CHECK VALVE
LIFT CONTROL VALVE PUMP SUPPLY
F738-WH
PRESSURE SWITCH FLOW COMPENSATOR
RIDE CONTROL AUTOSHIFT TRANSMISSION AUTO MODE ON SIGNAL FROM PREVIOUS VALVE TO TANK RESOLVERS
78
• Ride Con Control trol System System:: - Pow Power er shift shift transmission
The Ride Control System on machines with the optional autoshift transmission use the the Autoshift ECM. The Autoshift ECM monitors the position of the ride control switch and determines when to operate the ride control system. The ride control switch is a three position switch: OFF OFF,, ON and AUTO. When the key start switch is in the ON position, power is available at the ride control switch through the 614-PU wire and at the Autoshift ECM through the 123-WH wire. The Autoshift ECM monitors the ride control switch position at terminals terminals 21 and 22. When the ride control switch switch is in the OFF position, the circuits at terminals 21 and 22 of the the Autoshift ECM are open.
➥
STMG 746 STMG 10/02
- 107 -
When the ride control switch switch is in the ON position, power transfers to the ride control relay. relay. Power available at the ride control control switch illuminates the indicators in the switch and the ride control indicator on the instrument panel. • Ride cont control rol switc switch h ON: - If Autoshi Autoshift ft ECM senses: - Circuit Circuit at termin terminal al 22 closed - Pressu Pressure re switch switch closed - Then ride ride control control relay closes: - Ride Ride contr control ol solenoid energized
With the ride control switch closed, the Autoshift ECM reads a closed circuit at terminal 22 (Ride Control ON). This closed circuit confirms confirms to the Autoshift ECM that the ride control switch is in the ON position. Before the Autoshift ECM will create an output signal to energize the ride control solenoid, the condition of the pressure switch which is located in the rod end of the loader lift lift cylinder must be determined. determined. The pressure switch senses rod end cylinder cylinder pressure. If the rod end pressure pressure is below the actuation setting of the switch, the switch is closed and the Autoshift ECM will send a signal to close the ride control relay. relay. When the relay closes the solenoid is energized. If the pressure is is too high the switch is open and the Autoshift ECM will not send a signal to the relay. When the ride control solenoid is energized, pump supply oil flows through the solenoid to unseat the check valve and to shift the shut-off valve. This action connects the head end of the the loader lift cylinders to to the ride control accumulator, and the rod end of the loader lift cylinders are open to the tank through the check valve.
• Ride cont control rol switc switch h AUTO:
When the ride control switch switch is in the AUTO AUTO position the Autoshift ECM reads a closed circuit at terminal 21.
- If Autoshi Autoshift ft ECM senses:
A closed circuit at terminal 21 confirms to the Autoshift ECM that the ride control switch is in the AUTO position. Under this condition, the Autoshift ECM uses input from the pressure switch and the speed sensor to determine when to operate the ride control system.
- Circuit Circuit at termin terminal al 21 closed - Pressu Pressure re switch switch closed - Sufficien Sufficientt groun ground d speed - Then ride ride control control relay closes: - Ride Ride contr control ol solenoid energized
If the speed sensor input indicates ground speed is less than approximately 9.5 kilometers per hour (6 mph), the Autoshift ECM will not engage the ride control system. If the input indicates that that the ground speed is greater than approximately 9.5 kilometers per hour (6 mph), the Autoshift ECM directs an output signal to close the ride control relay. When the relay closes the solenoid is energized. NOTE: ET can be used used to adjust the speed at at which the the Autoshift Autoshift ECM engages Ride Control.
STMG 746 STMG 10/02
- 108 -
3 2
1
79
• Ride Con Control trol Syst System em components: 1. Rid Ride e con contro troll valv valve e 2. Ac Accu cumu mula lato tor r 3. Guard
The ride control valve (1) is located on the inside of the right frame rail below the cab. The accumulator (2) is protected by a guard (3).
STMG 746 STMG 10/02
- 109 -
DEAD ENGINE LOWER CIRCUIT SOLENOIDS ENERGIZED CONN. 19 1 2 BK-18 3 4
CONN. 19 GN-18 1 2 BK-18 3 PK-18 4 PK-18
85 87
86 30
BK-18
DEAD ENG. LOWER ENABLE RELAY BK-18
87
86 30
BK-18
YL-18
87A DEAD ENG LOWER COMMAND RELAY YL-18
GN-18
CONN. 12 1 2 3 4
CONN. 12
YL-18
BU-18 BK-18 YL-18 OR-18
1 2 3 4
BK-18 YL-18 GN-18
1 2 3 4 5 6
1 2
GN-18
BK-18 GN-18 BK-18
A B C
BU-18 RD-18 BK-18
8 1
3 5 MOM 4 6
CONN. 56
RD-18 BR-18 RH LOCK VALVE SOL.
2
WH-18 OR-18 PK-18 GN-18 BK-18 YL-18
RD-18 BR-18 LH LOCK VALVE SOL.
GN-18 WH-18 BK-18 PK-18 OR-18 1 DEAD ENG. LOWER SW. 2 OR-18 OR-18 YL-18 BK-18
BK-18
1 2
YL-18 GN-18
YL-18 GN-18
1 2 3 4
1 YL-18 2 GN-18 DEL. ARC SUPPR. 1 1 YL-18 2 GN-18 DEL. ARC SUPPR. 2 PU-18 PU-18 PU-18 7 BK-18
87A
85
CONN. 57 YL-18 BK-18 GN-18 BK-18
BK-18
A B C 7 MOM
FLOAT DETENT LIMIT SW. BU-18 RD-18 BK-18 8 1
2 MOM
3 4
5
6
FLOAT DETENT PILOT PRESS. SW.
DUAL FUNCTION RIDE CONTROL SWITCH
80
• Dead engi engine ne lower lower with loader lock valves
Some machines may be equipped with optional loader lock solenoid valves. For these machines a dead engine lower switch is required to energize the solenoids to allow the operator to lower the loader arms with a dead engine. The dual function ride control switch is used with machines equipped with ride control and the loader lock lock valves. When ride control is activated the lock valves solenoids are energized to allow ride control to work.
STMG 746 STMG 10/02
- 110 -
"D" SERIES MECHANICALLY CONTROLLED BACKHOE VALVES SIDESHIFT LOCK PISTONS PUMP
TANK
END COVER E-STICK STICK
COOLER
BUCKET BACK FLOW CHECK VALVE
SWING BOOM
SMU
AUX INLET MANIFOLD
S T E E R
RIGHT STABILIZER LEFT STABILIZER
LEVER
MANIFOLD
LEVER
L I F T
T I L T
A U X
81
Backhoe Valve Groups • Backh Backhoe oe valve valve group group:: - Mech Mechanica anically lly controlled
The following seven illustrations will cover the valves in the backhoe valve group that are mechanically operated. All of the valves are are closed-center. closed-center. Only the swing, E-stick E-stick and auxiliary valves are pressure compensated.
STMG 746 STMG 10/02
FROM PREVIOUS VALVE
- 111 -
BACKHOE AUXILIARY CONTROL VALVE HOLD PORT A
PORT B
PLUG
TO NEXT VALVE
FROM PUMP
FLOW CONTROL VALVE
82
• Backhoe Backhoe auxi auxiliary liary control valve in HOLD: - Pre Pressu ssure re compensated - Three position spool
The auxiliary valve shown here is used for the extendible stick or can be used for other backhoe attachments. These valves are controlled by foot pedals and are found in both the mechanical operated backhoe valve group and in the pilot operated backhoe valve group. The major components of these optional valves are the same as those in the auxiliary valve in the loader section, except these valves do not have a pilot operated line relief and makeup valve.
STMG 746 STMG 10/02
- 112 -
STICK CONTROL VALVE FROM PREVIOUS VALVE
HOLD
RESOLVERS
LINE RELIEF VALVE
ROD END
HEAD END
LINE RELIEF AND MAKEUP VALVE
TO NEXT VALVE
CONTROL SPOOL
LOAD CHECK VALVE
FROM PUMP
83
• Stick Stick control control valve valve in HOLD: - Mech Mechanica anically lly controlled
The stick control valve is equipped with a line relief valve for the rod end and a combination line line relief and makeup valve for the head end. The valve is not pressure compensated. The load check valve is not the same same as used on the "C" Series. The load check valve still serves the same function of o f preventing implement drift until system pressure increases to move the spool to the left to provide flow to the cylinder. Due to improved control spool design, an advance signal passage is no longer required for STICK OUT.
STMG 746 STMG 10/02
- 113 -
STICK CONTROL VALVE
FROM PREVIOUS VALVE
STICK OUT
RESOLVERS
LINE RELIEF VALVE
ROD END
HEAD END
LINE RELIEF AND MAKEUP VALVE
TO NEXT VALVE
CONTROL SPOOL
LOAD CHECK VALVE
FROM PUMP
84
• Stick Stick control control valve valve in STICK OUT
When an implement is activated and supply pressure is higher than cylinder pressure, the check valve is pushed to the left. Oil can then flow to the cylinder. As long as the system pressure is higher than the work port pressure, the load check valve will stay to the right.
STMG 746 STMG 10/02
- 114 -
BUCKET CONTROL VALVE FROM PREVIOUS VALVE
HOLD
ROD END
RESOLVERS
HEAD END
LINE RELIEF
TO NEXT VALVE
CONTROL SPOOL
FROM PUMP
LOAD CHECK VALVE
85
• Bucket Bucket contro controll valve valve in HOLD: - Mech Mechanica anically lly controlled
The bucket control valve contains line relief valves for the rod end and the head end of the cylinder. cylinder. The valve is not pressure pressure compensated.
STMG 746 STMG 10/02
- 115 -
FROM PREVIOUS VALVE
RESOLVERS
SWING CONTROL VALVE HOLD
ADVANCE SIGNAL PASSAGE
SWING LEFT
SWING RIGHT
CHECK VALVE
LINE RELIEF VALVE
SIGNAL METERING SLOT
TO NEXT VALVE
CONTROL SPOOL
FLOW CONTROL VALVE
FROM PUMP
86
• Swing Swing control control valve valve in in HOLD: - Sign Signal al metering metering slots improve modulation
• Ch Check eck val valves ves:: - Main Maintain tain pressure pressure on cylinder pistons in hold - Redu Reduce ce swing "wag" "wag"
To improve swing modulation, advance signal metering slots are machined in the main control spool. Inside the main control spool spool are two check valves. The spool also has advance signal passages. Inside the flow control spool spool is a load check valve which prevents swing drift. The check valves allow the system to maintain pressure on the cylinder pistons in HOLD. Due to the check valves, the main control spool is no longer a true closed-center control valve. By maintaining a pressure on both sides of o f the cylinder pistons during a swing, the amount of swing "wag" is reduced redu ced when the swing lever is returned to HOLD. The check valves will also act as makeup valves to prevent cylinder voiding.
➥
STMG 746 STMG 10/02
- 116 -
When the engine is not running, runn ing, the springs (only one spring shown for clarity) at the left end of the flow control c ontrol spool shift the spool to the right. The flow control valve is in a parallel circuit and has equal access ac cess to pump supply oil. When the engine is started, supply oil to the flow control spool enters the passage in the center of the spool and fills the chamber at the right end of the spool. As pressure increases on the right end of the flow control spool, the spool moves to the left against the springs. Supply oil then flows to to the main control spool where a small amount of oil flows past both check valves in the main control spool and enters both work ports. The oil is then blocked by the the cylinder pistons. This action maintains pressure on both ends of each piston. As the flow control spool moves to the left, the metering slots in the flow control spool begin to close creating a restriction to the pump supply oil. Because of the restriction, pressure in the work po rts and on the right end of the flow control spool spool is reduced. The pressure on the right end of the flow control spool, which is limited by the flow control springs, is the same as the pressure in the work ports. This pressure of 415 kPa (60 psi) is maintained in the work ports to improve the implement response when the main control spool is shifted. • Advan Advance ce signal signal operation
When the spool is initially shifted, the advance signal passage sends some pump supply oil to the signal cavity before oil is directed to the cylinders. The signal is then sent back to the pump control valve to upstroke the pump. The signal metering slots meter some of this signal signal pressure to the tank, thus preventing the pump from going to a "high pressure standby" mode. The signal metering slots provide more benefit to the operator when the spool is returned to the HOLD position. The slots meter the signal pressure to the tank and dampen the shock created by closing the spool. Operation of the swing is smoother and swing " wag" is further reduced. The signal metering slots also provide improved start-up metering. NOTE: A signal limiter was shown in the first verion of this Service Training Meeting Guide and other service literature. The limiter was removed just prior to first ship and is no longer used on the swing circuit for any "D" Series machine.
STMG 746 STMG 10/02
- 117 -
FROM PREVIOUS VALVE
RESOLVERS
SWING CONTROL VALVE SWING RIGHT SWING LEFT ADVANCE SIGNAL PASSAGE
SWING RIGHT
CHECK LINE RELIEF VALVE VALVE
SIGNAL METERING SLOT
TO NEXT VALVE
CONTROL SPOOL
FROM PUMP
FLOW CONTROL VALVE
87
• Sw Swing ing RIG RIGHT: HT: - Sup Supply ply oil unseats unseats left check valve - Retu Return rn oil unseats unseats left check valve - Left check valve valve provides a pressurized swing
When the spool is shifted to SWING RIGHT RIGHT,, the work port pressure is sent through the signal network network and to the flow control valve. Supply oil enters the main control spool and unseats the check valve on the right. Return oil from the swing right work port also enters the spool, unseats the right check valve, and flows to the tank. The left check valve creates a back pressure on the oil returning to the tank to provide a pressurized swing. Pressure oil on the right end of the flow control valve will work against the signal oil and springs on the left end of the flow control valve to maintain the desired flow rate to the swing circuit.
STMG 746 STMG 10/02
- 118 -
428D / 438D BOOM CONTROL VALVE FROM PREVIOUS VALVE
RESOLVERS
HOLD
ROD END
HEAD END
LINE RELIEF AND MAKEUP VALVE
TO NEXT VALVE
CONTROL SPOOL
LOAD CHECK VALVE
FROM PUMP
88
• Boom Boom control control valve in in HOLD: - Mech Mechanica anically lly controlled
The boom control valve contains combination line relief and makeup valves for the head end and rod end of the cylinder. The valve is not pressure compensated. The load check valve prevents prevents implement drift whenever a circuit is first activated or due to lack of flow, the system pressure is less than needed to support or move the load. Due to improved control spool design, an advance signal passage is no longer required for BOOM-UP on the 428D and 438D. On the 416D and 424D an advance signal passage is required. NOTE: Due to the improved line routings, the head end and rod rod end workports have been reversed on the "D" Series from the "C" Series on the boom and stick circuits.
STMG 746 STMG 10/02
- 119 -
"D" SERIES PILOT CONTROLLED BACKHOE VALVES AND STABILIZER VALVES SIDESHIFT LOCK CYLINDERS
PUMP
TANK END COVER E-STICK STICK BUCKET SWING BOOM AUX INLET MANIFOLD
RIGHT STABILIZER LEFT STABILIZER MANIFOLD
P A T T E R N C H A N G E R
J O Y S T I C K
COOLER
SMU
BACK FLOW CHECK VALVE
J O Y S T I C K
JOYSTICK
S T E E R
LEVER LEVER
PILOT SHUTOFF
L I F T
T I L T
A U X
RIDE CONTROL
89
• Pilot Pilot opera operated ted backhoe valve group
The following 12 illustrations are related to the pilot operated backhoe section valves, stabilizer valves and sideshift frame.
• Stab Stabiliz ilizer er valve valves s
All of the valves are are closed-center. closed-center. Only the swing, E-stick E-stick and auxiliary valves are pressure compensated.
• Side Sideshif shiftt fram frame e
STMG 746 STMG 10/02
- 120 -
5 1
2
4 3
90
• Backh Backhoe oe valve valve group group:: 1. Boom 2. Swing 3. Bucket 4. Stick 5. E-S -Sttic ick k
This illustration shows the pilot operated backhoe valve group located at the rear of the machine. Outlet ports to the cylinders cylinders face the rear of the the machine on all models. This change from the "C" Series resulted in improved line routing. The valve group can have up to six valve sections. Access to the secondary resolvers on center pivot machines must be done from below the machine instead of at the rear of the machine as was done on former backhoes.
STMG 746 STMG 10/02
- 121 -
3 1
2
91
• Hydr Hydrau auli lic c components: 1. Optio Optional nal pat patter tern n changeover valve
The optional pattern changeover valve (1) for the pilot operated backhoe valve group is mounted on the right side of the rear frame. The valve allows the operator to change from the excavator pattern to the backhoe pattern.
2. Pil Pilot ot shu shutof tofff valve valve 3. Pilo Pilott re retu turn rn manifold
Machines equipped with pilot hydraulics are equipped with a backhoe shutoff switch switch on the side console. The switch controls the pilot pilot shutoff solenoid valve (2) that is mounted on the front of the rear axle. The solenoid, when energized, allows pilot oil to flow to the joysticks. When the solenoid is de-energized the joysticks are disabled. To lower implements with a dead engine, en gine, the key start switch must be turned to the ON position. NOTE: The axles on the "D" Series no longer feature brake disc inspection ports.
STMG 746 STMG 10/02
- 122 -
STICK CONTROL VALVE FROM PREVIOUS VALVE
RESOLVERS
HOLD
LINE RELIEF VALVE
ROD END
TO NEXT VALVE
HEAD END
LINE RELIEF AND MAKEUP VALVE
CONTROL SPOOL
LOAD CHECK VALVE
PILOT PASSAGE
FROM PUMP
92
• Stick Stick control control valve valve in HOLD: - Pilo Pilott operated operated
The stick control valve is equipped with a line relief valve for the rod end and a combination line line relief and makeup valve for the head end. The valve is not pressure compensated. Except for being pilot controlled, the valve operation is the same as the mechanically controlled stick control valve.
STMG 746 STMG 10/02
- 123 -
BUCKET CONTROL VALVE
FROM PREVIOUS VALVE
HOLD
RESOLVERS
TO NEXT VALVE
ROD END
HEAD END
LINE RELIEF VALVE
CONTROL SPOOL
PILOT PASSAGE
LOAD CHECK VALVE
FROM PUMP
93
• Bucket Bucket contro controll valve valve in HOLD: - Pilo Pilott operated operated
The bucket control valve contains line relief valves for the rod end and the head end of the cylinder. cylinder. The valve is not pressure pressure compensated. Except for being pilot controlled, the valve operation is the same as the mechanically controlled bucket control valve.
STMG 746 STMG 10/02
- 124 -
SWING CONTROL VALVE HOLD
FROM PREVIOUS VALVE RESOLVERS
SIGNAL METERING SLOT
SWING LEFT
SWING RIGHT
CHECK VALVE
LINE RELIEF VALVE
TO NEXT VALVE
CONTROL SPOOL
PILOT PASSAGE
ADVANCE SIGNAL PASSAGE FLOW CONTROL VALVE
FROM PUMP
94
• Swing Swing control control valve valve in in HOLD: - Pilo Pilott operated operated
Except for being pilot controlled, the valve operation is the same as the mechanically controlled swing control valve. NOTE: A signal limiter was shown in the first verion of this Service Training Meeting Guide and other service literature. The limiter was removed just prior to first ship and is no longer used on the swing circuit for any "D" Series machine.
STMG 746 STMG 10/02
- 125 -
BOOM CONTROL VALVE FROM PREVIOUS VALVE
HOLD
ROD END
RESOLVERS
HEAD END
LINE RELIEF AND MAKEUP VALVE
TO NEXT VALVE
CONTROL SPOOL
PILOT PASSAGE
LOAD CHECK VALVE
FROM PUMP
95
• Boom Boom control control valve in in HOLD: - Pilo Pilott operated operated
Except for being pilot controlled, the valve operation is the same as the mechanically controlled boom control valve.
STMG 746 STMG 10/02
- 126 -
2
1
3
96
• Side Sideshif shiftt machin machines: es:
Sideshift machines feature a boom (1) that can ca n be shifted to different positions along a frame (2).
1. Boom
Lock pistons (not shown) are used to lock the boom to the frame rails. 2. Frame 3. St Stab abil iliz izer ers s
The stabilizers (3) are used to raise and lower the machine. Sideshift and center pivot machines use the same type of control valves to operate the stabilizers.
STMG 746 STMG 10/02
- 127 -
SIDESHIFT SLIDE LOCK SOLENOID VALVE RELEASED
ENGAGED
SOLENOID
PUMP SUPPLY
PUMP SUPPLY
CHECK VALVE SLIDE LOCK PISTON
SLIDE RAIL SLIDE BAR
97
• Sideshif Sideshiftt slide slide lock lock solenoid operation for ENGAG EN GAGED ED and RELEASED
This schematic shows the sideshift slide lock solenoid and orifice check valve operation. In the ENGAGED position, position, the solenoid is not energized. energized. The solenoid blocks the system oil flow. flow. Pump supply pressure can flow past the check valve to the slide lock pistons. pistons. The pistons clamp the stabilizer stabilizer frame slide rails against the bolts on the slide bars to preve nt slide frame movement. The check valve will seat as a s shown to maintain pressure on the pistons when system pressure decreases. In the RELEASED position, the solenoid solenoid is energized. The solenoid allows system supply oil to go to the tank. The slide lock pistons are are no longer pressurized. The slide bar can then move along the the slide rail.
STMG 746 STMG 10/02
- 128 -
1 2
3
98
• Stabiliz Stabilizer er circu circuit it components: 1. Stab Stabil iliz izer er valve valve group 2. Pil Pilot ot acc accumu umulat lator or 3. Pilot Pilot pre pressu ssure re test test port
The stabilizer valve group (1) and pilot accumulator (2) are mounted on the inside of the rear frame on the right side of the machine. The pilot accumulator provides dead engine implement lowering capabilities. The pilot accumulator is not used on the 416D, 424D, 428D and 438D. The pressure test port (3) is used for checking pilot system pressure. NOTE: All of the lines are are not connected in this view. The line from the pilot accumulator is to be connected to the stabilizer valve group.
STMG 746 STMG 10/02
- 129 -
416D / 424D / 428D / 438D BACKHOE STABILIZERS HYDRAULIC CIRCUIT SHIFT RIGHT STABILIZER LEFT PILOT RIGHT PILOT LEVER LEVER LEFT STABILIZER
RIGHT STABILIZER
LOCK CHECK VALVES PILOT LOCK CHECK VALVES
CHECK VALVE
ORIFICES RETURN MANIFOLD
PRESSURE REDUCING VALVE
SIGNAL TO BACKHOE SECTION
RESOLVER
SIGNAL FROM LOADER SECTION
FROM PUMP
99
• Stab Stabiliz ilizer er operatio operation: n: - Load check valves valves - Pilo Pilott lock check check valves
The stabilizer schematic shown is for machines equipped with mechanical controls for the backhoe and loader valve groups. The left stabilizer is in HOLD and the right stabilizer is being SHIFTED. The stabilizer cylinders are controlled by closed-center valves equipped with lock check valve and pilot lock check valves. The check valves prevent cylinder drift in either direction. Pilot control valves are used to shift the stabilizer control spools. Orifices and resolvers are used to signal the pump as to flow needs of the stabilizer circuits. When a pilot control lever is shifted, pilot oil is sent to one side of the stabilizer control spool to shift it. As the spool shifts, some pilot oil is directed to a pilot lock check valve.
➥
STMG 746 STMG 10/02
- 130 -
When the pilot lock check valve shifts, blocked oil that was working with the lock check valve spring to keep the lock check valve seated to prevent cylinder drift is allowed to drain to the tank. When this occurs, the lock check valve shifts opening one side of the stabilizer cylinder to the tank. Pump supply oil from the stabilizer control spool now flows through the other lock check valve into one of the stabilizer cylinder ports to move the cylinder either up or down. Also when the stabilizer control spool is shifted, some of the pump supply oil also becomes signal oil to signal the pump. When the pilot control lever is released, the spring in the pilot lock check moves to block oil from flowing to the tank through the check valve. This blocked oil works with the spring on the lock check valve to seat the lock check valves. Oil is now trapped in in both sides of the stabilizer stabilizer cylinders. The stabilizer stay locked in in position.
STMG 746 STMG 10/02
- 131 -
420D / 430D / 432D / 442D BACKHOE STABILIZERS HYDRAULIC CIRCUIT SHIFT RIGHT STABILIZER LEFT PILOT RIGHT PILOT LEVER LEVER PILOT ACCUMULATOR
LEFT STABILIZER
RIGHT STABILIZER
LOCK CHECK VALVES
CHECK VALVE
PILOT LOCK CHECK VALVES
RETURN MANIFOLD
TO JOYSTICKS
ORIFICES
PRESSURE REDUCING VALVE
PILOT SHUT OFF RESOLVER
SIGNAL TO BACKHOE SECTION
SIGNAL FROM LOADER SECTION
FROM PUMP
100
• Stabiliz Stabilizer er circuit circuit for for pilot controls:
The stabilizer valves used on machines with pilot controls for the backhoe and loader operate the same as on machines with mechanical controls.
- Pilo Pilott accumulator accumulator
Machines equipped with pilot controls are also eq uipped with a pilot accumulator to allow implement lowering capabilities with a dead engine.
- Pilo Pilott shutoff shutoff solenoid
The key start switch must be turned to the ON position to shift the pilot shutoff solenoid to allow pilot flow to the joysticks. Refer to the Operation and Maintenance Manual for the respective machine for additional information on lowering the implements if the accumulator has bled down.
STMG 746 10/02
- 132 -
AUTO-UP STABILIZER SYSTEM TIMER ACTIVATED / SOLENOIDS ENERGIZED
1 2
PU-18 BK-18
PU-18 BK-18
LEFT STAB. UP SW.
1 2 CONN. 48
1 2 RIGHT STAB. UP SW.
PU-18 BK-18
PU-18 BK-18
1 2 CONN. 48
ALARM VALVE GP BK-18 1 2 3 4
YL-18 BU-18
1 2
CONN. 17
1 2 CONN. 48
1 2 RIGHT STAB. UP SW.
PU-18 BK-18
1 2 L. STAB UP DETENT
YL-18 BK-18
1 2
YL-18 BK-18
PU-18 1 BK-18 2 CONN. 48 BU-18 BK-18 PU-18 YL-18
A-1 B-2 B-1 C-1
BAT(+) GND(-) INPUT(S) OUTPUT(L)
STAB. TIMER
R. STAB. UP DETENT DETENT VALVE GP
OR-18 PU-18
+ -
PU-18 BK-18
LEFT STAB. UP SW,
1 2
ALARM DIODE BLOCK
PU-18 BK-18
HORN ALARM
1 2 3 4
BK-18
CONN. 12
STAB. LEG ALARM
BK-18 YL-18 OR-18
1 2 3 4 CONN. 12
STAB. LEG UP DETENT
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• Auto-up stabilizer system
The auto-up stabilizer system is an option that allows the operator to move the stabilizer pilot control lever into a solenoid detent position to raise the stabilizer stabilizer.. The stabilizer up switches are located in the stabilizer control valve group and are closed by the stabilizer pilot control lever. The timer holds the control lever in the detent position for approximately 10 seconds. After 10 seconds the stabilizers stabilizers should be fully raised. raised. The stabilizer alarm advises operator that the stabilizers are down when the operator shifts the transmission out of NEUTRAL. NOTE: The timer is activated the instant the stabilizer pilot control lever is moved. The timer starts before the lever is placed in the detent position.
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TST 1
TST 2
THERMAL RELIEF VALVE
IRM LEFT VALVE
HOLD
ALL WHEEL STEER CONTROL VALVE GROUP
CIRCLE STEER VALVE
IRM SHUTOFF VALVE
ALL WHEEL STEER SYSTEM
RESOLVER IRM RIGHT VALVE
PILOT POPPET VALVES LOCK VALVE
RESOLVER
PILOT POPPET VALVES
REAR AXLE
FROM STABILIZER VALVE GROUP
CROSSOVER LINE RELIEF VALVES
TO BACKHOE VALVE GROUP RETURN
AUXILIARY LOADER VALVE GROUP
FRONT AXLE
STEERING METERING METERING UNIT
BACK FLOW CHECK VALVE
TILT LIFT SIGNAL
TO STABILIZER VALVE GROUP STEERING PRIORITY VALVE TO BACKHOE VALVE GROUP
TO BRAKE VALVE
102
All Wheel Steer System (AWS) • All Whee Wheell Steer Steer
The All Wheel Steer (AWS) system system is similar to what was used on the "C" Series machines. Operation of the AWS AWS valve is the same. The major differences between the models are: - Since the "D" Series AWS AWS system uses non-boosted non-boosted brakes, a steering and brake resolver is no longer in the signal line between the steering priority valve and the SMU. - Due to the reverse signal network, the lines routing routing between the valve sections has changed. - The swit switch ch to cont control rol AWS has has been been changed changed to to two sep separa arate te butto buttons ns as shown earlier earlier..
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MACHINE SECURITY SYSTEM MACHINE OPERABLE GN-18 PK-18
MACHINE SECURITY CONTROL (MSC) BATTERY GROUND DRIVER NO. 2 OUTPUT EXCITER COIL SIGNAL LINE DRIVER NO. 1 INPUT DRIVER NO. 1 OUTPUT UNUSED DRIVER NO. 2 INPUT LED GROUND KEY SWITCH ON POSITION INPUT ALTERNATOR R TERMINAL INPUT UNUSED KEY SWITCH CRANK POSITION INPUT UNUSED CAT DATA LINK + CAT DATA LINK UNUSED UNUSED EXCITER COIL RETURN LINE DRIVER NO. 1 GROUND RETURN RED LED SIGNAL LINE GREEN LED SIGNAL LINE DRIVER 2 ENABLE INPUT UNUSED UNUSED UNUSED
1 3 5 7 9 11 13 18 19 24 26 29 31 40 42 45 47 52 53 58 60 62 64 66 68 70
1 2
EXCITER COIL
A B C
RD-18 BK-18 BU-18 YL-18 PK-18 GN-18
RD-18 YL-18 OR-18
A B C
BU-18 BK-18 PK-18
1 2 3 4
RD-18
OR-18 BK-18 PK-18 YL-18
BK-18 BK-18 GN-18 OR-18
OR-18
PK-18
OR-18 BR-18
YL-18 BU-18 GN-18 PU-18 GN-18 PK-18 YL-18 PK-18
PK-18 PK-18 PU-18 GN-18 GN-18
1 2 3 4 GN-18 PK-18
MSS ENGINE RELAY PK-14
OR-18 BR-18
GN-18 BK-18 PK-18 PK-14
1 2
85 87
86 30
87A
CAT DATA LINK
PU-18 PU-18 GN-18 BK-18
A B C
RED GN-18 BK-18
GREEN
MSS LED INDICATOR
103
OPTIONAL MACHINE SECURITY SYSTEM (MSS) • Machine Machine Secu Security rity System: - Thef Theftt deterrent deterrent - Uses Caterpi Caterpillar llar Electronic Keys
The Machine Security System (MSS) is a theft the ft deterrent and reduces the chance of unwanted machine operation. operation. MSS uses Caterpillar Caterpillar Electronic Keys that have unique identification numbers. The MSS uses a Machine Security Control (MSC) (MSC) with the the keys. The MSC can be programmed with the key ID's to to restrict or allow allow access to the machine. No two keys have the same ID and are not configurable. Electronic Technician Technician is used to program the MSC.
- Mach Machine ine Security Security Control (MSC)
➥
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The exciter coil will read the ID of the key. key. The exciter coil is mounted around the existing existing key start start switch. The MSC will will check the the ID of the key for the authorization. If the key is authorized by the MSC, the machine will operate normally. normally. The MSS will keep critical critical machine functions disabled if the key does not match any authorized keys in the MSC. The MSS LED indicator indicator provides basic MSS information to the machine operator. The green LED indicates the machine is operable, while the red LED indica indicates tes the machine machine is inoperable. inoperable. The MSS can be installed in one of two ways: - Disabling power to two items that that are currently on the machine. Solenoids and relays can be controlled with this method. - Causing another ECM to disable a critical machine function unless an authorized authorized ID ID key is used. To make modifications to the MSS, the technician must have a key with Master Access Level for that MSS or a "factory password." The factory password is determined from the following items: Product ID, Software Part Number from the Machine Security Control, Serial Number from a registered version of ET and a tattletale. A factory password can be used one time.
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104
CONCLUSION • Co Concl nclusi usion on
This presentation has provided an overall review of the steering and implement hydraulic systems used in the "D" Series Bac khoe Loaders. When used in conjunction with the service manual, the information in this package should permit the serviceman to do a thorough job of analyzing a problem in these systems. For service repairs, adjustments and maintenance, always refer to the Owner and Operator Manual, Service Manuals and other related service publications.
