Service Manual of RS8160 Road Roller
SERVICE MANUAL
9 Working Hydraulic System
Service Manual for G9165 Grader
CONTENTS 9
Working Hydraulic System ................... ............................ ................... ................... ................... ................... ................... ............... ..... 9-1
91 General ................................................................................................................. 9-1 92 Description, Disassembly and Assembly of Main Components .................. ....................... ..... 9-10 921 Working Pump Pu mp ................................. ................ ................................. ................................ ................................ .......................... .......... 9-10 922 Hydraulic Oil Tank .................................................................................... 9-15 923 Multitandem Valve .................................................................................... 9-23 924 Rotary Control Valve ................................................................................ 9-31 925 Middle Swivel Joint ................................................................................... 9-38 926 Hydraulic Oil Cylinders ................... ............................ ................... ................... ................... .................... ................... .........9-44 927 Other Hydraulic Components ................... ............................ ................... ................... ................... ................... ........... .. 9-48 93 Pressure Measurement of Working Hydraulic System ................ .......................... ................... ........... .. 9-50 94 Service Precautions for Working Hydraulic System................... ............................ ................... ............. ... 9-51 95 Diagnosis of Common Faults of Working Hydraulic System................... System........................... ........ 9-54
I
Service Manual for G9165 Grader
9 Working Hydraulic System 91 General G9165 adopts double-circuit double-constant-displacement-pump open-type working hydraulic system, which consists of an enclosed tank, two high-pressure gear pumps, two multitandem valves and hydraulic cylinders, rotary valve and the pipelines. System pressure is controlled by pressure valve inside the multitandem valve and system set pressure is 21MPa. The hydraulic lock that installed on front wheel tilt cylinder and front and rear frame hinge, and the balance valve installed on shovel blade lifting cylinder can prevent the shifting due to the weight of equipment itself and load so as to ensure the safety of moving and the operation accuracy of blade. The working devices of G9165 grader are powered by two high-pressure gear pumps, and the two pumps are installed on transmission box PTO port. The left main pump is used supply high-pressure oil to the left multitandem valve and the right main pump is used to supply high-pressure oil to the right multitandem valve. Because of the design, the operational stability and accuracy of the grader are improved, and the machine can continue to work if one of the two pumps is faulty. Rotation of shovel blade is realized by rotating of the whole rotary gear ring, which is driven by rotary valve + double oil cylinders and engagement of rotar y gear ring and a small gear. Hydraulic oil tank
Radiator
Working pump
Multitandem valve
Multitandem valve Working device
Fig. 9-1 Oil flow route of working hydraulic system
9-1
Service Manual for G9165 Grader
Fig. 9-2 Working hydraulic principle diagram 9-2
Service Manual for G9165 Grader Up/down of shovel blade
The two shovel blade lifting cylinders are controlled respectively by the left multitandem valve and right multitandem valve, and supplied by two oil lines with the same oil flow, so the two shovel blades can be lifted or lowered synchronously, working accuracy of the grader is improved. And the balance valve installed on the lifting cylinder can prevent the shifting due to the weight of equipment itself and load so as to ensure the safety of moving and the operation accuracy of blade.
Fig. 9-3 Up/down of shovel blade 1 Right blade lifting cylinder
2 Left blade lifting cylinder
3 Right multitandem valve (1A/1B)
4 Left multitandem valve (10A/10B)
5 Balance valve
Swing of shovel blade
Power source of the blade swing cylinder is from the fifth valve group of right multitandem valve.
Fig. 9-4 Swing of shovel blade 1 Blade swing cylinder
2 Right multitandem valve (5A/5B) 9-3
3 Balance valve
Service Manual for G9165 Grader Tilt (change cutting angle) and sidesway of shovel blade
Power source of the blade tilt cylinder and blade sidesway cylinder are from the fourth valve group and third valve group of left multitandem valve, respectively. The middle swivel joint can prevent the hydraulic pipes from intertwining when the shovel blade is rotating.
Fig. 9-5 Tilt (change cutting angle) and sidesway of shovel blade 1 Left multitandem valve (7A/7B and 8A/8B)
2 Middle swivel joint
3 Blade tilt cylinder
4 Blade sidesway cylinder Tilt of front wheels
Fig. 9-6 Tilt of front wheels 1 Hydraulic lock
2 Front wheel tilt cylinder
3 Right multitandem valve (3A/3B) 9-4
Service Manual for G9165 Grader
Power source of the front wheel tilt cylinder is from the third valve group of right multitandem valve. The hydraulic lock acts as a stabilizing force in the front wheel tilt oil line, eliminating the swing phenomenon between front wheels and front frame during driving. Hinge steering
Power source of the steering cylinder is from the fourth valve group of right multitandem valve. The balance valve acts as a stabilizing force during steering, eliminating the twist phenomenon between front frame and rear frame caused by load deflection.
Fig. 9-7 Hinge steering 1 Right multitandem valve (4A/4B)
2 Balance valve
3 Hinge steering cylinder
Shovel blade rotation
Fig. 9-8 Shovel blade rotation 1 Left multitandem valve (6A/6B)
2 Rotary control valve
3 Blade rotary cylinder
Power source of the shovel blade rotary cylinder is from the fifth valve group of left multitandem valve. Pressure oil is allocated to the two rotary cylinders through the rotary control valve. The rotary cylinders drive the two hardened small gears to rotate the rotary frame, so as to realize blade 9-5
Service Manual for G9165 Grader
rotation. Unlike many other grader manufactures, we adopt double-oil-cylinder rotary mechanism rather than “hydraulic motor + turbine reducer ” mechanism. To enable the rotary frame rotate continuously, the drive arm of the left rotary cylinder and right rotary cylinder are arranged with 90° difference. Two hardened small gears are used to drive the rotary frame, and in the meantime a gear is used to drive the rotary control valve element, thus, pressure oil can be supplied to the two cylinders in proper connecting order to realize continuous rotating of shovel blade. Up/down of front bulldozing plate (optional module)
Power source of the front bulldozing plate lifting cylinder is from the second valve group of right multitandem valve. Front bulldozing plate is an optional attachment, and the standard model is not equipped with this attachment. When the bulldozing plate is not installed, the corresponding oil ports of multitandem valve are sealed with screw plug.
Fig. 9-9 Up/down of front bulldozing plate 1 Right multitandem valve (2A/2B)
2 Front bulldozing plate lifting cylinder
Up/down of rear scarifier
Power source of the rear scarifier lifting cylinder is from the second valve group of left multitandem valve. Rear scarifier is an optional attachment, and the standard model is not equipped with this attachment. When the rear scarifier is not installed, the corresponding oil ports of multitandem valve are sealed with screw plug.
9-6
Service Manual for G9165 Grader
Fig. 9-10 Up/down of rear scarifier 1 Left multitandem valve (9A/9B)
2 Rear scarifier lifting cylinder
Up/down of middle scarifier
Fig. 9-11 Up/down of middle scarifier 1 Left multitandem valve (2A/2B)
2 Middle scarifier lifting cylinder
Power source of the middle scarifier lifting cylinder is from the second valve group of right multitandem valve. Middle scarifier is an optional attachment, and the standard model is not 9-7
Service Manual for G9165 Grader
equipped with this attachment. When the middle scarifier is not installed, the corresponding oil ports of multitandem valve are sealed with screw plug. Locking cylinder
Power source of the locking cylinder is from port A of prefill valve in brake hydraulic system, a magnetic exchange valve is designed in the circuit to control the cylinder. A rocker switch is installed in the cab to control the magnetic exchange valve to retract or extend the cylinder.
Fig. 9-12 Locking cylinder 1 Locking cylinder
2 Magnetic exchange valve
3 Rocker switch
Shovel blade floating (replaceable module)
Compared to standard model, the common balance valve is replaced with floating balance valve. And a duplex solenoid valve is used to control the on-off state of oil line from prefill valve port A to floating balance valve, so as to realize floating of shovel blade. Two rocker switches installed in the can are used to control floating of the two blade lifting cylinders.
9-8
Service Manual for G9165 Grader
Fig. 9-13 Blade floating 1 Right shovel blade lifting cylinder 3 Floating balance valve
2 Left shovel blade lifting cylinder
4 Oil return block
7 Right lifting cylinder floating switch
5 Duplex solenoid valve
8 Left lifting cylinder floating switch
9-9
6 Prefill valve
Service Manual for G9165 Grader
92 Description, Disassembly and Assembly of Main Components 921 Working Pump Table 9-1 Items
Parameter
Nominal displacement
32ml/r
Rated/max. pressure
25/31.5MPa
Rated/max. speed
20MPa
Volumetric efficiency
≥0.92
Number of teeth
14
Direction of turning
Left-hand
Fig. 9-15 Working pump
Working principle
When pump shaft rotates as Fig. 9-15, the gear demeshes on oil absorption chamber side, oil absorption chamber close volume increases and partial vacuum will be formed, oil in the tank will be pressurized into absorption chamber through the oil absorption pipe under the force of atmospheric pressure to fill up the inter-tooth space. As the gear rotates, oil in transition area will be brought into oil extrusion chamber, the gear meshes on the extrusion side and the volume decreases to force oil into oil circuit. Fig. 9-16 Gear pump working principle
9-10
Service Manual for G9165 Grader Composition of working pump
Fig. 9-16 Composition of working pump 1 Retainer ring
2 Retainer ring
3 Antifriction bearing
4 Lip-type seal ring for rotating shaft
5 Front cover
6 Bearing
7 Rectangular seal ring
8 Gasket
10 Lug seal ring 11 Side plate
12 Driving gear shaft
13 Driven gear shaft
14 Rivet
16 Rear cover block
17 Bolt
15 Label
9 Lug retainer ring
Disassembly and assembly of working pump
ATTENTION Before dismantling the working pump, be sure to carefully read 95 Ser vice Precauti ons for in this chapter. Work i ng H ydraul ic System Disassembly of working pump
1.
Connect a hose to the oil draining valve on the bottom of hydraulic tank, and put the other end in a clean vessel. Open the drain valve of the tank to drain the hydraulic oil out. (Open the filling cap of the tank to accelerate the draining speed)
ATTENTION Cover
1
the
discharged
contamination.
Fig. 9-17 1. Oil drain valve
9-11
oil
to
prevent
Service Manual for G9165 Grader
2.
Remove the head board fixing bolts, and take down the cover plate.
1 Fig. 9-18 1. Head board 3.
Remove the fixing screws of working pump oil absorption steel pipe, take down the screws fission flange, and the remove the steel pipe and O-shape ring.
1 Fig. 9-19 1 Working pump oil absorption steel pipe 4.
Disconnect the oil outlet rubber hose of working pump.
1 Fig. 9-20 1 Straight joint
9-12
Service Manual for G9165 Grader
5.
Remove the fixing bolts of working pump, take down the bolts and gaskets.
6.
Hang the working pump with lift appliance, and then use a copper bar to knock the pump outward, take down the pump and sealing gasket.
7. 1 Fig. 9-21 1. Bolt
Remove the fixing screws of the straight joint, take down the screws, fission flange and
2
straight joint.
2 Sealing gasket
Assembly of working pump
1.
Use four screws and a fission flange to connect the straight joint to the pump oil outlet port. 70~80Nm
1 Fig. 9-22 1. Straight joint
2.
Use four M12 bolts and gaskets, and a sealing gasket to connect the working pump to transmission box PTO port. 78~104Nm
1 Fig. 9-23 1. Bolt
2
2 Sealing gasket
9-13
Service Manual for G9165 Grader
3.
Connect the oil outlet rubber hose to the straight joint.
1 Fig. 9-24 1 Working pump oil outlet rubber hose
4.
Put O-ring in the O-ring groove of working pump oil absorption steel pipe joint. Fix the pipe on the working pump with four screws and a fission flange. 70~80Nm
1 Fig. 9-25 1 Working pump oil absorption steel pipe 5.
Install the head board with bolts
6.
Fill hydraulic oil to specified level.
1 Fig. 9-26 1. Head board
9-14
Service Manual for G9165 Grader
922 Hydraulic Oil Tank It is used to provide oil to the whole hydraulic system. An oil return filter is designed in the tank to ensure the cleanliness of hydraulic oil.
Fig. 9-27 Hydraulic oil tank assembly 1 Bolt
2 Gasket
6 Bolt
7 Thick gasket
12 Oil draining joint 16 O-ring
3 Oil filling filter element 8 Gasket
13 O-ring
17 Oil absorption flange
21 Oil absorption filter element assembly 25 Oil return filter
9 Nut
4 Round oil level pointer 10 Oil draining joint
14 Oil return flange
5 Tank 11 Ball valve 15 Ring magnet
18 Gasket
19 Bolt
20 Sealing gasket
22 O-ring
23 Screw plug
24 Air filter
26 Bolt
Description of hydraulic tank components:
1.
Air filter: Since the hydraulic oil in the tank expands when heated and contracts when cooled, so the hydraulic oil tank must connect with the atmosphere. The air filter is used to balance the air pressure inside the tank and atmospheric pressure. It also works as a filter to keep the circulating air clean and dry, to guarantee the cleanliness of hydraulic oil.
2.
Oil level pointer: Used to check hydraulic oil level.
3.
Oil return filter: Used to filter oil contamination out. If there is too much contamination 9-15
Service Manual for G9165 Grader
accumulated in filter element, which will increase pressure difference between two sides of the filter, the filter build-in bypass valve will open if the pressure difference gets to its opening pressure, oil will be released through bypass valve to ensure the hydraulic system operation normal.
Oil absorption filter element
Oil filling filter element
Air filter
Oil return filter
Oil level pointer
Disassembly and assembly of hydraulic oil tank
ATTENTION Before dismantling the hydraulic oil tank, be sure to carefully read the 94 Ser vice Precauti ons for Worki ng H ydr auli c System .
9-16
Service Manual for G9165 Grader Disassembly of hydraulic oil tank
1.
Operate the control handles to lower the shovel blades to the ground and raise the front bulldozing plate to the highest position, and then shut down the engine. Then operate the control handle to lower the front bulldozing plate to the ground.
Fig. 9-28
2.
Connect a hose to the oil draining valve on the bottom of hydraulic tank, and put the other end in a clean vessel. Open the drain valve of the tank to drain the hydraulic oil out. (Open the filling cap of the tank to accelerate the draining speed)
ATTENTION Cover
1
the
discharged
oil
to
prevent
contamination.
Fig. 9-29 1. Oil drain valve
3.
Remove the engine hood. Refer to 8 Cab & Covering Parts System for disassembly of engine hood.
4.
Remove the fixing bolts of left and right guard plates, use lifting rope to hang the plates down.
5.
1 2 Fig. 9-30 1 Engine hood 3 Head board
3 2 Guard plate
9-17
Remove the head board.
Service Manual for G9165 Grader
6.
Disconnect the brake pump oil outlet rubber hose and prefill valve oil inlet rubber hose from the high-pressure filter.
1
2
Fig. 9-31 1 Brake pump oil outlet rubber hose 2 Prefill valve oil inlet rubber hose
7.
Disconnect the oil return pipes from hydraulic oil tank.
1 2 3 4 Fig. 9-32 1 Oil return pipe from port T of high-pressure filter safety valve 2 Oil return pipe from port T of oil return block 3 Oil outlet pipe from port T of priority valve 4 Oil pipe from port O of prefill valve
9-18
Service Manual for G9165 Grader
1 Fig. 9-33 1 Radiator oil return pipe 8.
Disconnect the hydraulic tank oil outlet rubber hose from working pump oil absorption steel pipe.
1
2
Fig. 9-34 1 Working pump oil absorption steel pipe 2 Fixing clamp 9.
Remove the fixing bolts of hydraulic oil tank support, lift down the tank.
1 Fig. 9-35 1 Bolt
9-19
Service Manual for G9165 Grader Assembly of hydraulic oil tank
1.
Lift the hydraulic oil tank to the rear frame for assembling, install and tighten the fixing bolts. 78~104Nm
1 Fig. 9-36 1 Bolt 2.
Install the clamps to connect the hydraulic tank oil outlet rubber hose to working pump oil absorption steel pipe.
1
2
Fig. 9-37 1 Working pump oil absorption steel pipe 2 Fixing clamp
9-20
Service Manual for G9165 Grader
3.
Connect the oil return pipes to hydraulic oil tank.
ATTENTION Mark the hydraulic pipes orderly to prevent confusion.
Part 1: Straight joint 45~65Nm Oil pipe 45~65Nm Part 2: Oil pipe 45~65Nm
1 2 3 4 Fig. 9-38 1 Oil return pipe from port T of high-pressure filter safety valve 2 Oil return pipe from port T of oil return block 3 Oil outlet pipe from port T of priority valve 4 Oil pipe from port O of prefill valve
Part 3: Straight joint 45~65Nm Oil pipe 45~65Nm Part 4: Oil pipe 45~65Nm Radiator oil return pipe 120~145Nm
1 Fig. 9-39 1 Radiator oil return pipe
9-21
Service Manual for G9165 Grader
4.
Connect the brake pump oil outlet rubber hose and prefill valve oil inlet rubber hose to the high-pressure filter. Part 1: Straight joint 65~85Nm Part 2: Straight joint 45~65Nm
1
2
Fig. 9-40 1 Brake pump oil outlet rubber hose 2 Prefill valve oil inlet rubber hose 5.
Install the fixing bolts of head board.
6.
Install the fixing bolts of left and right guard plates.
7.
Assemble the engine hood. Refer to 8 Cab & Covering Parts System for assembly of engine hood.
8. 1 2 Fig. 9-41 1 Engine hood 3 Head board
3 2 Guard plate
9-22
Fill hydraulic oil to specified level.
Service Manual for G9165 Grader
923 Multitandem Valve The grader is designed with two multitandem valves, and each multiandem valve is mainly composed of valve body, five valve groups in series, check valve and relief valve. Operate the control handles to control the valves elements, so as to obtain the motion we desired.
Fig. 9-42 Schematic diagram of multitandem valve Inlet check valve : Used to prevent reflux of pressure oil, to avoid cylinder dive. Main relief valve: The valve a pilot operated cartridge valve, and set pressure of the valve is
214Bar. Function of valve groups in multitandem valve
Right multitandem valve
Left multitandem valve
Fig. 9-43 Multitandem valve 1 Up/down of shovel blade 4 Hinge steering
2 Up/down of front bulldozing plate
5 Swing of shovel blade
8 Sidesway of shovel blade
6 Rotary cylinder
9 Scarifier
3 Tilt of front wheels 7 Tilt of shovel blade
10 Up/down of shovel blade 9-23
Service Manual for G9165 Grader Composition and structure of multitandem valve
Fig. 9-44 Structure of right multitandem valve 1 Valve element end cap
2 End cap fixing nut
3 Valve element end cap fastening screw
4 Spring seat
5 Spring
6 Operating valve block assembly
7 Flat gasket — Seal
8 Dust ring
9 O-ring
10 Valve element assembly
11 Valve body
12 Seal assembly
13 Operating valve block assembly
16 Check valve element 19 Oil outlet valve block assembly 22 Fastening screw
23 Nut
26 Valve element assembly
17 End cap fixing nut 20 Nut 24 Relief valve assembly 27 Valve body
9-24
14 O-ring
15 Spring
18 Oil inlet valve block assembly 21 Fastening screw 25 Plug assembly
Service Manual for G9165 Grader
Fig. 9-45 Structure of left multitandem valve 1 Valve element end cap
2 End cap fixing nut
3 Valve element end cap fastening screw
4 Spring seat
5 Spring
6 Operating valve block assembly
7 Flat gasket — Seal
8 Dust ring
9 O-ring
10 Valve element assembly
11 Valve body
12 Seal assembly
13 Operating valve block assembly
16 Check valve element 19 Oil outlet valve block assembly 22 Fastening screw
23 Nut
26 Valve element assembly
17 End cap fixing nut 20 Nut 24 Relief valve assembly 27 Valve body
9-25
14 O-ring
15 Spring
18 Oil inlet valve block assembly 21 Fastening screw 25 Plug assembly
Service Manual for G9165 Grader
Disassembly and assembly of multitandem valve
ATTENTION Before dismantling multitandem valve, be sure to carefully read the 94 Ser vice Pr ecauti ons for . Work i ng H ydr auli c System Disassembly of the multitandem valve
1.
Remove the fixing bolts of the left and right guard plates, take down the bolts and guard plates.
1 Fig. 9-46 1 Left guard plate
2.
Remove the fixing bolts of the plate, take down the bolts and plate.
1 Fig. 9-47 1 Plate
9-26
Service Manual for G9165 Grader
3.
Remove the connecting bolts of the control pull rod and multitandem valve connecting rod. Take down the bolts, nuts and gaskets.
1 2 3 Fig. 9-48 1 Multitandem valve connecting rod 2 Control pull rod 3 Bolt 4.
Disconnect the oil pipes from multitandem valve.
ATTENTION Mark the hydraulic pipes orderly to prevent confusion.
1 Fig. 9-49 1 Oil pipe 5.
Remove the connecting nuts of multitandem valve support and frame. Lift down the valve.
1
2
Fig. 9-50 1 Multitandem valve support 2 Nut
9-27
Service Manual for G9165 Grader
6.
Remove the pipe joints.
7.
Remove the cotters and connecting pins.
8.
Remove the fixing screws of multitandem
1 Fig. 9-51 1 Pipe joint
1 2 3 Fig. 9-52 1 Multitandem valve connecting rod 2 Cotter 3 Connecting pin
valve.
1 Fig. 9-53 1 Screw
9-28
Service Manual for G9165 Grader Assembly of the multitandem valve
1.
Fix multitandem valve on the support with screws.
2.
Install the cotters and connecting pins.
3.
Install the pipe joints to the corresponding oil
1 2 3 Fig. 9-54 1 Multitandem valve connecting rod 2 Cotter 3 Connecting pin 4 Screw
ports of multitandem valve. Pipe joint 35~45Nm
1 Fig. 9-55 1 Pipe joint 4.
Install multitandem valve assembly to the machine with four M10 nuts. Nut 45~59Nm
1
2
Fig. 9-56 1 Multitandem valve support 2 Nut 9-29
Service Manual for G9165 Grader
5.
Connect the oil pipes to multitandem valve orderly. Pipe 65~85Nm
1 Fig. 9-57 1 Oil pipe 6.
Use bolts to connect the control pull rod and multitandem valve connecting rod.
1 2 3 Fig. 9-58 1 Multitandem valve connecting rod 2 Control pull rod 3 Bolt 7.
1 Fig. 9-59 1 Bolt
2 2 Plate
9-30
Install the fixing bolts (M6×20) of the plate.
Service Manual for G9165 Grader
8.
Use M6×20 bolts to fix the left and right guard plates on cab.
1 Fig. 9-60 1 Left guard plate
924 Rotary Control Valve The rotary control valve is installed on top of the connecting rack, and it is the main component of shovel blade rotary mechanism. Its function is to supply pressure oil to the two cylinders in proper connecting order to realize continuous rotating of shovel blade.
Fig. 9-61 Rotary control valve
9-31
Service Manual for G9165 Grader
Fig. 9-62 Schematic principle diagram of rotary control valve Working principle of rotary control valve
During rotation of shovel blade, port AA of rotary is always connected with chamber A of rotary control valve, and port BB of rotary is always connected with chamber B of rotary control valve. In the initial position, the left rotary cylinder is fully retracted and in the same line with the drive arm, it doesn’t output driving force at this point. The right rotary cylinder is in the middle of its stroke and cylinder rod is perpendicular to the Fig. 9-63
drive arm, it outputs the maximum driving force at this point. The pressure oil from port AA enters rod-side chamber of the right rotary cylinder through the valve, and the oil in the piston-side chamber of the cylinder returns to port BB through the valve. Under this circumstance, the piston rod of right rotary cylinder retracts to drive the rotary frame to rotate anticlockwise via the drive arm and small gear. Meanwhile, rotary valve element will be driven by gear to achieve synchronous rotation. 9-32
Service Manual for G9165 Grader
As the rotary valve element rotates, the pressure oil from port AA enters piston-side chamber of the left rotary cylinder and rod-side chamber of the right rotary cylinder through the valve. Under this circumstance, the piston rod of left rotary cylinder extends and that of right rotary cylinder retracts to drive the rotary frame to rotate anticlockwise collaboratively. Fig. 9-64
When the left rotary cylinder is perpendicular to the left drive arm, the right rotary cylinder and drive arm are in the same line. At this point, only the left rotary cylinder drives rotary frame to rotate anticlockwise.
Under
this
circumstance,
the
pressure oil from port AA enters piston-side chamber of the left rotary cylinder, and the oil in the rod-side chamber of the cylinder returns to port Fig. 9-65
BB through the valve.
When the left rotary cylinder is 180° to the left drive arm, the left rotary cylinder and drive arm are in the same line. At this point, only the right rotary cylinder drives rotary frame to rotate anticlockwise. Under this circumstance, the pressure oil from port AA enters piston-side chamber of the right rotary cylinder, and the oil in the rod-side chamber of the cylinder returns to port BB through the valve. Fig. 9-66
9-33
Service Manual for G9165 Grader
When the left rotary cylinder is 225° to the left drive arm, the pressure oil from port AA enters rod-side chamber of the left rotary cylinder and piston-side chamber of the right rotary cylinder through the valve. Under this circumstance, the piston rod of left rotary cylinder retracts and that of right rotary cylinder extends to drive the rotary frame to rotate anticlockwise collaboratively. Fig. 9-67 When the left rotary cylinder is 270° to the left drive arm, the right rotary cylinder and drive arm are in the same line. At this point, only the left rotary cylinder drives rotary frame to rotate anticlockwise.
Under
this
circumstance,
the
pressure oil from port AA enters rod-side chamber of the left rotary cylinder, and the oil in the piston-side chamber of the cylinder returns to port BB through the valve. Fig. 9-68
Working principle for clockwise rotation of shovel blade is similar.
9-34
Service Manual for G9165 Grader
Disassembly and assembly of rotary control valve
ATTENTION Before dismantling rotary control valve, be sure to carefully read the 94 Ser vice Pr ecauti ons . for Worki ng H ydraul ic System Disassembly of the rotary control valve
1.
Disconnect all oil pipes from rotary control valve.
ATTENTION Mark the hydraulic pipes orderly to prevent confusion.
Fig. 9-69 1 Pipe joint
2 Oil pipe 2.
Screw off the three fixing bolts of rotary control valve, take down the bolts and gaskets.
3.
Take down the valve.
4.
Take down the transmission shaft, sleeve, and
Fig. 9-70 1 Bolt
the gaskets between rotary control valve and frame.
Fig. 9-71 1 Gasket
2 Transmission shaft 9-35
Service Manual for G9165 Grader
5.
As shown in Fig. 9-72, use a clamp to fix the rotary control valve, and then remove the pipe joints.
Fig. 9-72 1 Pipe joint
2 Rotary control valve
Assembly of the rotary control valve
1.
As shown in Fig. 9-73, use a clamp to fix the rotary control valve, and then install the pipe joints.
Fig. 9-73 1 Pipe joint
2 Rotary control valve
2.
Install the same number of gaskets as that of the removed ones. Install the transmission shaft and sleeve.
Fig. 9-74 1 Gasket
2 Transmission shaft
9-36
Service Manual for G9165 Grader
3.
Fix the rotary control valve on frame with bolts.
Fig. 9-75
4.
Tighten the valve fixing bolts.
5.
Connect the oil pipes to the corresponding oil
Fig. 9-76 1 Bolt
ports of rotary control valve.
Fig. 9-77 1 Pipe joint
2 Oil pipe
9-37
Service Manual for G9165 Grader
925 Middle Swivel Joint The middle swivel joint is installed on top-middle area of swing frame. The middle swivel joint can prevent the hydraulic pipes from intertwining when the shovel blade is rotating.
Technical parameters
Rotary torque: 30~60Nm When assembling the swivel joint, make sure it can rotate freely and no external force is exerted on it.
Fig. 9-78
a, b — to shovel blade tilt cylinder
c, d — to shovel blade sidesway cylinder
Fig. 9-79 Schematic diagram of middle swivel joint 1 Screw plug 2 O-ring 3 Rotary shaft 4 Water seal 5 Anti-wear ring 6 Rotary seal ring 7 Rotary body 8 Water seal 9 Baffle 10 Gasket 11 Bolt Fig. 9-80 Middle swivel joint assembly 9-38
Service Manual for G9165 Grader
Disassembly and assembly of middle swivel joint
ATTENTION Before dismantling the middle swivel joint, be sure to carefully read the 94 Service Precauti ons f or Wor ki ng H ydr auli c System .
Disassembly of the middle swivel joint
1.
Disconnect the two oil pipes.
2.
Remove the four fixing nuts of cover plate, take down the nuts and gaskets.
3.
Hold up the cover plate gently.
ATTENTION Be gently when holding up the cover plate, there are two oil pipes under the plate.
1 2 3 4 Fig. 9-81 1 To piston-side chamber of blade swing cylinder oil pipe 2 To rod-side chamber of blade swing cylinder oil pipe 3 Cover plate 4 Nut
4.
Disconnect the two oil pipes under the cover plate, take down the cover plate.
ATTENTION Mark the hydraulic pipes orderly to prevent confusion.
1 2 Fig. 9-82 1 To piston-side chamber of blade swing cylinder oil pipe 2 To rod-side chamber of blade swing cylinder oil pipe
9-39
Service Manual for G9165 Grader
5.
Disconnect the four oil pipes from the middle swivel joint.
ATTENTION Mark the hydraulic pipes orderly to prevent confusion.
1 2 3 4 Fig. 9-83 1 To port 8B of multitandem valve oil pipe 2 To port 8A of multitandem valve oil pipe 3 To port 7B of multitandem valve oil pipe 4 To port 7A of multitandem valve oil pipe
1 Fig. 9-84 1 Plate
6.
Remove the fixing nuts of the plate.
7.
Remove the fixing bolts of the four pipe
2 2 Nut
clamps.
1 Fig. 9-85 1 Pipe clamp 9-40
Service Manual for G9165 Grader
8.
Disconnect the four bottom oil pipes from the middle swivel joint.
ATTENTION Mark the hydraulic pipes orderly to prevent confusion.
9.
Remove the four pipe joints.
10. Remove the six fixing nuts of the middle swivel joint, take down the nuts and gaskets. 1 2 3 4 Fig. 9-86 1 To rod-side chamber of blade tilt cylinder oil pipe 2 To rod-side chamber of blade sidesway cylinder oil pipe 3 To piston-side chamber of blade tilt cylinder oil pipe 4 To piston-side chamber of blade sidesway cylinder oil pipe
Then take down the bolts and middle swivel joint.
Assembly of the middle swivel joint
1.
Use six M12 bolts and nuts to fix the middle swivel joint on frame.
2.
Install the four pipe joints. 45~65Nm
3.
Connect the four bottom oil pipes to the corresponding oil ports of middle swivel joint. 65~85Nm
1 2 3 4 Fig. 9-87 1 To rod-side chamber of blade tilt cylinder oil pipe 2 To rod-side chamber of blade sidesway cylinder oil pipe 3 To piston-side chamber of blade tilt cylinder oil pipe 4 To piston-side chamber of blade sidesway cylinder oil pipe
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Service Manual for G9165 Grader
4.
Use bolts, nuts and gaskets to fix the plate on bottom of middle swivel joint.
1 Fig. 9-88 1 Plate
2 2 Nut 5.
Use M10×20 bolts and pipe clamps to fix oil pipes on the connecting plate.
1 Fig. 9-89 1 Pipe clamp 6.
Connect the four upper oil pipes to the middle swivel joint. Pipe joint 45~65Nm Oil pipe 65~85Nm
1 2 3 4 Fig. 9-90 1 To port 8B of multitandem valve oil pipe 2 To port 8A of multitandem valve oil pipe 3 To port 7B of multitandem valve oil pipe 4 To port 7A of multitandem valve oil pipe
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Service Manual for G9165 Grader
7.
Connect the two oil pipes under the cover plate. Oil pipe 65~85Nm
1 2 Fig. 9-91 1 To piston-side chamber of blade swing cylinder oil pipe 2 To rod-side chamber of blade swing cylinder oil pipe
8.
Use the bolts and nuts to fix cover plate.
9.
Connect the two top oil pipes. Oil pipe 65~85Nm
1 2 3 4 Fig. 9-92 1 To piston-side chamber of blade swing cylinder oil pipe 2 To rod-side chamber of blade swing cylinder oil pipe 3 Cover plate 4 Nut
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Service Manual for G9165 Grader
926 Hydraulic Oil Cylinders
Fig. 9-93 Structure of hydraulic oil cylinder 1 Piston fixing nut
2 Piston seal
3 Piston
4 Cylinder tube
5 Cover
6 Wearing ring
7 O-ring
8 Back-up ring
9 Seal ring for shaft
10 Dust ring
11 Piston rod
12 Cylinder cover nut
13 Flat gasket
Specification of hydraulic oil cylinders applied in the grader working hydraulic cylinder
Table 9-2
Unit: mm Cylinder diameter
Piston rod diameter
Piston travel
115
50
303
4120004769
90
50
1379.5
Shovel blade swing cylinder
4120004768
90
50
693.5
Locking cylinder
4120004765
80
60
63.5
Shovel blade rotary cylinder
4120004766
80
35
279.5
Shovel blade sidesway cylinder
4120004767
90
50
1346
Shovel blade tilt cylinder
4120004771
100
50
260.5
Front wheel tilt cylinder
4120004762
100
50
169
Cylinder name
Product code
Hinge steering cylinder
4120004770
Shovel blade lifting cylinder
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Service Manual for G9165 Grader Precautions when disassembling hydraulic oil cylinder:
1
Be sure to unload the hydraulic system (pressure relief) before disassembling the cylinder. Otherwise high-pressure oil in the circuit will spray out at high speed when disconnecting the hydraulic oil pipes, safety accident may occur. Thus, before disassembling you should loosen the regulating handle or pressure adjusting screw of relief valve to unload the hydraulic circuit first, and then turn off the power source to shut down the entire hydraulic system. At this point, you can start to disconnect the oil pipes. To prevent getting hurt by residual pressure oil, you should loosen the pipe joint slowly and pay attention to check whether there is overflowing oil, be careful in this process.
2
Hydraulic oil cylinder is the actuator of hydraulic system. So before removing the cylinder, be sure to hang or support its driven device (working device) properly to prevent hurting people or crushing the machine. Before disassembling, you can start the machine and operate the control handles to let the cylinder move to suitable position for the convenience of assembling, and do not forget to unload the hydraulic system after that.
3
Before disassembling the hydraulic oil cylinder, you should pay attention to check whether the cylinder is designed with hydraulic lock. If so, remove the hydraulic lock first. Otherwise the cylinder will contain pressure oil locked by the hydraulic lock, which will make it difficult to disassemble the cylinder and bring potential hazard to the people and machine. When removing the hydraulic lock, you can use clean cloth to wrap up the connecting area (pipe joint, or something similar) first, to avoid splashing of high-pressure oil .
4
When disassembling the hydraulic oil cylinder, you should be aware of the main structure of the cylinder, never do the disassembling work blindly. Since different hydraulic oil cylinder has different size, structure and use purpose, they are intended to be disassembled in differ ent ways. So before the disassembling, you can refer to the cylinder engineering drawings provided by our company. If the drawings are not available, you should check the cylinder carefully and set a proper disassembly sequence.
5
In a general way, when disassembling the hydraulic oil cylinder, you should drain the hydraulic oil in the cylinder out first, and then remove the end cover, then pull out the piston rod and piston assembly. When disassembling the components, do not hammer fiercely. If it is inevitable, a copper bar should be used to avoid damaging the parts. Some parts need to be disassembled with special tools, these tools must be available. For fine thread part, you can use a copper rod to vibrate it first, and then use special wrench to loosen it gently, do not bump it fiercely. Some bolts were coated with thread locking sealant when assembling, which are hard to disassemble, and the thread may get damaged if you remove the bolt forcibly. In this case, 9-45
Service Manual for G9165 Grader
you can heat the bolt to let the sealant fall out first. 6
Pay attention to avoid damaging the piston rod thread, oil port thread, piston rod surface and inner wall of cylinder sleeve. Long and thin part (piston rod) should be placed on suitable support to prevent getting deformed or distorted. Do not use sharp tools to disassemble the seals to avoid scratching them. If the seals are difficult to disassemble, you can soak them in water to soften them, and then remove them. Before and after disassembling the cylinder, you should always take measures to prevent the parts and components from getting contaminated by dust and impurities. For example, the maintenance work should be performed in clean environment, and use plastic cloth rather than cotton cloth to cover the disassembled components and parts.
7
The disassembled parts and components should be inspected carefully, damaged and aged part/component should be replaced. In the case that the cylinder had severe internal or external leakage problem during normal use, if the piston rod and cylinder tube are in good condition, then the problem must be caused by worn or aged seals. If the cylinder tube was subject to strike damage, you should use internal dial gauge to check whether the tube is deformed. Check the cylinder tube, piston rod and other moving parts for scratch and pull damage, replace the repair the damaged parts according to the damage condition. If the damaged part is determined to be repaired, you should grind to flat the damaged area with fine oil stone first, and then polish it with abrasive paper.
Precautions when assembling hydraulic oil cylinder:
1
All parts and components should be cleaned and dried before assembling, parts and components that need to be coated with sealant when assembling should be cleaned with cleaning agent or acetone. Curing time of the sealant is about 20min, which means you should tighten the coated part/component to required torque in 20min.
2
Install the seals correctly. When installing an O-ring, do not drag/expand it to the state of permanent deformation or roll along the shaft to assemble it, otherwise it may get twisted and result in oil leakage. When installing a Y-ring, V-ring or stepped labyrinth seal ring, pay attention to the installing direction, a reversely fitted Y-ring, V-ring or stepped labyrinth seal ring will cause oil leakage. For Y-ring, its lip should face the pressure oil chamber, and pay attention to differentiate if the Y-ring is for shaft or for hole, do not install a wrong Y-ring. V-ring is composed of a back-up ring, a seal ring and a compression ring. The back-up ring can deform the seal ring for sealing, when installing the seal ring, the side with open mouth should face the pressure oil chamber. When adjusting the compression ring, it should be limited to no oil leakage, do not compress it too tight to avoid oversized sealing resistance. For stepped 9-46
Service Manual for G9165 Grader
labyrinth seal ring, the stepped end should face the pressure oil chamber. If the seal is for moving part or fits with moving part, coat it with hydraulic oil when assembling. Disassembled seal ring and dust ring should be replaced with new ones. 3
Bolts and lock nuts for pressure-bearing part/component are disposable, do not reuse them. Pressure-bearing
part/component
should
not
be
replaced
arbitrary,
original
spare
parts/components are preferable. Most of the fixing or connecting bolts have tightening torque and tightening order requirements, some of them even have tightening angle requirements. So when tightening the bolts, be sure to use a special wrench or torque wrench and follow these requirements. Bolts of the same component should be tightened to the same torque symmetrically. Long and thin part (piston rod) should be placed on suitable support to prevent getting deformed or distorted when tightening the fastening bolts. 4
Some piston seals will swell after being assembled, which may get cut or scratched when assembling the piston and piston rod assembly. In this case, you should use cone shrinking sleeve to shrink the seal. If there is no cone shrinking sleeve, you can make one by yourself according to the dimensions of piston and cylinder tube. Generally, the taper of the sleeve should be about 30°, and diameter of the small end of the sleeve should be equal to that of the cylinder tube. After assembling the piston and piston rod, you should measure the coaxiality and straightness in the overall length.
5
All moving parts and components should be coated with hydraulic oil for lubrication when assembling. The fine thread of some large part should be coated with lubricating grease, if the thread was subject to burn damage, coat it with molybdenum disulfide grease for lubrication.
6
After the maintenance, you must perform pressure leak tests before putting the machine into operation again. If the cylinder is designed with hydraulic lock, the hydraulic lock mustn ’t be installed during the tests. When performing the test, you should retract and extend the cylinder for several times at low pressure to discharge the air, and pay attention to check for any abnormal phenomenon. Then increase the pressure gradually to check for leakage.
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Service Manual for G9165 Grader
927 Other Hydraulic Components Hydraulic lock
The hydraulic lock is composed of two pilot operated check valves. When the reversing valve is in neutral position and the hydraulic system is loaded, the hydraulic lock can keep the cylinder stopped at the original position. For working hydraulic system of G9165 grader, the front wheel tilt circuit and up/down of scarifier circuit are designed with hydraulic lock. Table 9-3 Item
Parameter
Rated pressure
240Bar
Rated flow
55L/min
Opening pressure
2.1Bar
Pilot ratio
4:1
Fig. 9-94 Balance valve
The balance valve can change resistance coefficient automatically according to working condition (pressure difference) of the system. When the system pressure varies in a certain range, the balance valve can keep the oil flow the same. For working hydraulic system of G9165 grader, the hinge steering circuit, shovel blade swing circuit and up/down of shovel blade circuit are designed with balance valve. Table 9-4 Items
Parameter
Control pressure area ratio
4:1
Set pressure
240Bar
Flow
70L/min
Max. working pressure
350Bar
Fig. 9-95 Floating balance valve
Compared to common balance valve, the floating balance valve is designed with floating function. When there is pressure oil acts on the control port D, the two check valves inside the floating balance valve will open. At this point, both piston-side chamber and rod-side chamber of shovel 9-48
Service Manual for G9165 Grader
blade lifting cylinder are connected to oil return channel, and the shovel blade is in floating condition under the weight of working device and its own weight.
Fig. 9-96 Duplex solenoid valve
The duplex solenoid valve is used to control the on-off state of oil line from prefill valve to control port of floating balance valve, so as to realize floating of shovel blade.
Table 9-5
Fig. 9-97 Cross relief valve
Fig. 9-98 9-49
Items
Parameter
Rated pressure
207Bar
Voltage
24V
Service Manual for G9165 Grader
93 Pressure Measurement of Working Hydraulic System Pressure measuring tools
Pressure gauge with measuring range of 40MPa, piezometer tube Pressure measuring points
Oil inlet port of multitandem valve
Fig. 9-99 Right multitandem valve
Fig. 9-100 Left multitandem valve
Pressure measuring method
Raise the cylinders to build pressure. Standard working hydraulic system pressure
214.1±3.5Bar.
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Service Manual for G9165 Grader
94 Service Precautions for Working Hydraulic System The most common fault for high-pressure and high-precision hydraulic devices is that fouling (alien material) occurs in the hydraulic circuit. Thus, pay special attention to the cleanliness when adding hydraulic oil or removing and refitting the hydraulic devices. 1.
Pay attention to working environment.
Avoid adding hydraulic oil, replacing filter or repairing machine in rain or at windy and dirty place. 2.
Removing
and
servicing
machine
on
outdoor site.
Chances are that fouling will enter the equipment if removal and service are done on outdoor site; moreover, it is difficult to
Fig. 9-101
appraise
equipment’s
performance
after
eliminating the faults. So this is only suitable for
replacing
components.
Removal
and
service of the hydraulic devices should be conducted in special dust-free workshop and the performance of the hydraulic devices should be appraised with special testing device. 3.
Seal up the openings.
After removing the pipes or components, all openings should be sealed with cap, adhesive paper or plastic bag so as to prevent fouling or dirt from entering them. If you let the openings be exposed or clogged with rags, fouling is liable to get into them or the leaking oil will stain the surrounding places, which is not allowed to happen. Instead of draining oil on Fig. 9-102
the ground, you should collect the drained oil and take it back to handle it on your own.
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Service Manual for G9165 Grader
4.
Prevent any fouling or dirt from entering the system during the oil refilling operation.
Prevent any fouling or dirt from being mixed into the hydraulic oil when refilling hydraulic oil and be sure to keep the oil filler and the surrounding surface clean as well as use clean oil pump and container. Utilizing oil cleaning device will filter the fouling deposited during the storage period from the oil, which is more Fig. 9-103
effective for refilling oil. 5.
The hydraulic oil should be changed when the oil temperature is high.
When the hydraulic oil or other oil is hot, their fluidity is good and the deposited sludge is easy to be flushed away by the oil. Therefore, it is recommended to change oil when the oil is hot. Discharge the old oil fully (not only the oil in the hydraulic oil tank but also the oil in the filter and plugs of the pipeline) as possible as you can when changing oil. If there is old oil residual, the fouling and deposited sludge will be mixed with the new oil, shortening the service life of the new oil. 6.
Flushing operation.
The fouling, oil sludge and old oil in the hydraulic oil circuit should be flushed away
Rinsing oil
with rinsing oil when changing oil after the disassembly and assembly of the hydraulic devices. Normally, flushing is conducted for two times: primary flushing with rinsing oil and
secondary
hydraulic oil.
Fig. 9-104
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flushing
with
specified
Service Manual for G9165 Grader 7.
Cleaning operation.
Get rid of the sludge and fouling in the hydraulic oil circuit with oil cleaning device after repairing the hydraulic device (pump, control valve, etc.) or when the machine is operating. The oil cleaning device is used to remove the ultrafine granule that cannot be removed by the filter in the hydraulic device, which is a very effective cleaning tool. Fig. 9-105 8.
Torque requirements
The securing operation should be conducted in strict accordance with the torque required in this manual during the process of removal, refitting and service of the hydraulic system. Excessive or insufficient torque will lead to hydraulic oil leakage.
ATTENTION For the torque that is not indicated, please refer to relevant requirements in Chapter 0 General of this manual.
9.
Deflation (air bleeding) of working hydraulic system
After replacement of hydraulic pump, hydraulic cylinder, hydraulic pipe, joint and all kinds of valves, bleeding operation must be done. The specific bleeding steps are as follows: 1)
Open the filler cap of hydraulic tank.
2)
Start the engine; run the engine at idle for 5 minutes, and then retract and extend all cylinders from bottom for about 2~3 times, keep the stroke within 50~60 mm.
3)
Keep the engine run at low speed, and then retract and extend all cylinders fully for about 3~5 times to bleed the air in hydraulic circuit.
4)
After the bleeding, set the machine and working device in standard position, check hydraulic oil level and tighten the filler cap.
5)
Shut down the engine, check for leakage.
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