TR_Tram_EN

TECHNICAL TRAINING MANUAL

TECHNICAL TRAINING MANUAL TRAMMING CIRCUIT

SANDVIK TAMROCK SECOMA S.A. 19 avenue De Lattre-de-Tassigny - ZI B.P. 46 - 69881 MEYZIEU Cedex Tel : (33) 472 45 22 00 Fax : (33) 478 31 79 80

AXLE TRAMMINGTRAMMING- EN 03 06 F S

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TECHNICAL TRAINING MANUAL MANUAL

TABLE OF CONTENT 1

AXLE TYPE, TRAMMING CIRCUIT

3

1/1

GENERAL ARRANGEMENT

3

1/2

OVERALL CIRCUIT

4

1/2/1

BASIC PRINCIPLE

5

1/3

TRAMMING PUMP

6

1/3/1

HYDRAULIC SYMBOL

7

1/3/2

CHARGE PRESSURE CIRCUIT

8

1/4

SERVO-CONTROL OPERATION ION

13

1/5

HYDRAULIC BRAKING

19

1/5/1

FORWARD DIRECTION ENGAGED

19

1/5/2

MAXIMUM BRAKING CAPABILITY

20

1/6

SAFETY BRAKING CIRCUIT

21

1/7

HYDRAULIC MOTOR

23

1/7/1

FLAT GROUND TRAMMING

24

1/7/2

UP U PWARD IN AN INCLINE

25

1/8

HYDROSTATIC BRAKING

28

1/9 1/9

HYDR HYDROS OSTA TATI TIC C & EM EMER ERGE GENC NCY Y AUTO AUTOMA MATI TIC C BRAK BRAKIN ING. G.(O (OPT PTIO ION) N)

29

1/10 1/10

MECH ME CHAN ANIC ICAL AL BRAK BRAKIN ING G (OPT (OPTIO ION) N)

30

1/11

ABA BRAKES (OPTION)

32

2

WHEEL MOTORS

33

2/1

PRINCIPLE

33

2/2

CHARGE PRESSURE

34

3

SANDVIK TAMROCK SECOMA S.A. 19 avenue De Lattre-de-Tassigny - ZI B.P. 46 - 69881 MEYZIEU Cedex Tel : (33) 472 45 22 00 F ax : (33) 478 31 79 80

AXLE TRAMMINGTRAMMING- EN 03 06 F S

2 ( 34 )


TABLE OF CONTENT 1


3

1/1

GENERAL ARRANGEMENT

3

1/2

OVERALL CIRCUIT

4

1/2/1

BASIC PRINCIPLE

5

1/3

TRAMMING PUMP

6

1/3/1

HYDRAULIC SYMBOL

7

1/3/2


8

1/4

SERVO-CONTROL OPERATION ION

13

1/5

HYDRAULIC BRAKING

19

1/5/1


19

1/5/2

MAXIMUM BRAKING CAPABILITY

20

1/6

SAFETY BRAKING CIRCUIT

21

1/7

HYDRAULIC MOTOR

23

1/7/1


24

1/7/2

UP U PWARD IN AN INCLINE

25

1/8

HYDROSTATIC BRAKING

28

1/9 1/9

HYDR HYDROS OSTA TATI TIC C & EM EMER ERGE GENC NCY Y AUTO AUTOMA MATI TIC C BRAK BRAKIN ING. G.(O (OPT PTIO ION) N)

29

1/10 1/10

MECH ME CHAN ANIC ICAL AL BRAK BRAKIN ING G (OPT (OPTIO ION) N)

30

1/11

ABA BRAKES (OPTION)

32

2

WHEEL MOTORS

33

2/1

PRINCIPLE

33

2/2

CHARGE PRESSURE

34

3


AXLE TRAMMING- EN 03 06 F S

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MODULE 1) 1.1


General arrangement Hydraulic motor A

B

The tramming circuit is of “hydrostatic close loop type”. This circuit consists of a variable displacement double way pump and one hydraulic motor.

Neutral position: the pump is driven by the Diesel engine, due to pump in neutral position there is no flow delivered at either outlet of the pump. Therefore the motor is not running, the machine does not move.

Hydraulic pump A

B

One way tramming: the pump supplies flow out of the port B to the port B of the hydraulic motor. The motor in now running, the machine moves.

Reverse direction: from the pump flow is now supplied from the opposite outlet port A. The motor runs in the opposite direction, the machine moves in reverse.

NOTE: most of the oil is recycled from the pump to the motor then back to the pump. CAUTION: avoid contamination within the circuit so as to prevent particles of foreign material to be recirculating many times in the H.P. loop circuit

!

WARNING: WARNING: DUE TO VERY HIGH PRESSURE INVOLVED IN THIS TYPE

OF “HYDROSTATIC TRANSMISSION CIRCUIT” ALWAYS USE GENUINE MAIN LINE HOSES S.A.E. 100R9 R TYPE. SANDVIK TAMROCK SECOMA S.A. 19 avenue De Lattre-de-Tassigny - ZI B.P. 46 - 69881 MEYZIEU Cedex Tel : (33) 472 45 22 00 Fax : (33) 478 31 79 80


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1.2

Overall circuit 13

11

2 bar

T

14

B93 B

r

12

P

B92 A

a

m

m

2 .8

.8

b m 0

b R

9

B

A

T

P

B

A

T

P

m 0

B01

B02

AR

a

T2 T1

PS

Fa2

Fa1

Fe

U

Mb

B

X1

X2

M1

B 470 bar

470 bar

28 bar

440 bar

A X1

X2

G

Mh

S

Ma

AV

2mm

A

G

T

The tramming circuit includes: ITEM 9 10 11

FUNCTION Tramming variable displacement pump Variable displacement motor Forward/backward solenoid control valve

ITEM 12 13 14

FUNCTION Low/High-speed, solenoid control valves Air cooler Case drain safety relief valve


10

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1.2.1

BASIC PRINCIPLE

Hydraulic motor and pump are both of variable displacement piston type. A swash plate controls the displacement of the pump and the motor.A servo-control valve operates the servo-cylinder. The servo-cylinder moves the swash plate. This hydraulic system is designed to automatically adjust itself according to the power available from the Diesel engine. It tries as far as possible to use the lowest pression according to the ground condition. It always let the Diesel engine alive even when the steering pump is consuming power together with the tramming one. At full engine RPM, the "hydraustatic" circuit adapt the power consumption as shown in the curve below.

MACHINE OVERALL CAPABILITY MOTOR

MOTOR

TORQUE

DISPLACEMENT

up to 3

minimum

mini. 35 cm3 /rev

157 l/mn

lowest 200

highest

minimum

2

maximum

maxi. 107 cm3 / rev

157 l/mn

around 250 *

medium

medium

1

maximum

maxi. 107 cm3 / rev

76 l/mn

up to 440

lowest

maximum

OPERATION

PUMP FLOW

PRESSURE IN

VELOCITY

BAR

TRACTIVE EFFORT

.

P 440

T

1

≈ 30%

250

2

≈ 6%

3

200

Vmax

0%

V km/h

* According to the machine load, the motor settings can be adjusted. SANDVIK TAMROCK SECOMA S.A. 19 avenue De Lattre-de-Tassigny - ZI B.P. 46 - 69881 MEYZIEU Cedex Tel : (33) 472 45 22 00 Fax : (33) 478 31 79 80


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1.3

Tramming pump 3

HPb X1

Ps T1

R

X2

B

Mb

1 T2

Ma 2

G

A

G

S

HPa

T1

B

X1

Y1 R

3 Fa

X2

Y2 HP.B

PS

X1 R B

DA

G Ps Ma Mb

MA

CP G

T2

ITEM

MB

OF

X2

Y2

T2

HP.A

Ps

FUNCTION Charge pressure to safety brakes, accelerator Pilot pressure test point High pressure test point

R

Air bleeding plug

S T1

Suction inlet line Drain line to air cooler

1 2 3

DA cartridge, pilot pressure valve Charge pressure relief valve H.P. control valve

ITEM

FUNCTION

T2

2 bar drain relief line, direct to tank

Fa X1 X2 Y1 Y2

After filter, charge pressure test point

HPa HPb

High pressure safety relief, line A High pressure safety relief, line B

Pilot pressure acting on servo-cylinder Forward direction, inlet pilot port (HP A) Backward direction, inlet pilot port (HP B)

NOTE: on hydraulic schematics “cp>xb” means that the backpressure should never exceed the pressure indicated. For example the pressure in the line to the air cooler should always be maintained below 2 bar. These are used on case drain lines to prevent over pressure, which can damage the shaft seals.


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1.3.1

HYDRAULIC SYMBOL

4

1

b R

7

a

T2 T1

PS

Fa2

Fa1

Fe

Mb B

5

6

470 bar

8

470 bar

28 bar

440 bar

A X1

HP

ITEM

X2

G

2

Mh

S

Ma

3

FUNCTION

ITEM

1

DA valve

6

2

Charge pressure relief valve

7

3 4 5

H.P. control valve Servo control valve Servo cylinder

8 HP

FUNCTION Charge pressure pump Charge pressure filter (including by-pass valve) Main piston pump H.P. safety relief valves



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1.3.2


VIEW A

DIESEL ENGINE

Filter

S

A

1 SP

BP

DP

DA

2 M H

2 SANDVIK TAMROCK SECOMA S.A. 19 avenue De Lattre-de-Tassigny - ZI B.P. 46 - 69881 MEYZIEU Cedex Tel : (33) 472 45 22 00 F ax : (33) 478 31 79 80

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1 - LUBRICATION FUNCTION While engine is running if the machine is not moving, the pump does not deliver flow at either main lines A or B. First purpose of the charge circuit is to supply pressure to lubricate all internal moving parts. Hydraulic fresh oil from the tank enters the pump at the suction port S. The charge pump (internal gear type) is linked to the main shaft, therefore it runs at the same RPM as the main pump (engine RPM). At the outlet of the charge pump, oil is directed to the filter then to the charge relief valve2 through the DA valve 1.. NOTE: The outlet of the charge pressure relief valve flows directly into the housing of the pump. This is used for cooling all components with fresh and clean oil. From the pump housing, see drain portT1, drain oil flows to the tank through the air cooler then directly to tank without filtration to prevent building up of back pressure. Due to this cooling circuit a large flow can be seen at the drain line. That does not means that the tramming component are leaking or worn out. THE PUMP ROTATE CLOCKWISE LOOKING

TO THE SHAFT SIDE.

THE

CHARGE FLOW PASSES THROUGH THE FILTER THEN

BACK INTO THE PUMP.

NOTE : WHEN THE FILTER ELEMENT IS CLOGGED, THE FILTER RELIEF VALVE RECYCLES THE OIL BACK TO THE CHARGE PUMP INLET LINE. A CLOGGED FILTER RESULTS IN DROP OF CHARGE PRESSURE. Charge pressure flows as well to the H.P. relief valves. They include a check valve function, which allows charge pressure to be directed to both main lines A and B. On the drawing beside you can see the old relief valve , now replace by the new relief type . Charge pressure lubricates pistons, bronze pads BP in contact to the swash plate SP and the distributor plate DP. Hydraulic symbol

b R

a

T2 T1

PS

Fa2

Fa1

Fe

Mb

B 470 bar

470 bar

28 bar

440 bar

A X1

X2 HP

G

Mh

S

Ma

2



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2 - INTERNAL

LEAKAGES , SIMPLIFIED SCHEMATIC

b R

a

T2 T1

PS

Fa2

Fa1

Fe

Mb B

470 bar

470 bar

440 bar

28 bar

A X1

X2

G

Mh

S

Ma

HPb HPb

1

DA

2 M H

HPa

2

While tramming, both motor and pump are working at high pressure. Tramming pressure range from 50b up to 440b. There is internal leakage at the motor and pump. Leakage flows into the case drain lines. The flow returning from the motor back to the pump is not equal to the flow at the H.P. outlet port. In the example shown, the flow in line A is greater then the flow in line B, due to the motor internal leakage. To prevent vacuum which damage components, the charge pump will make up the amount of oil lost into the drain line. The charge pressure flows through the HPb relief valve into the main line B.


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3 - SWASH PLATE CONTROL Reminder: charge pressure pump is a gear type (fixed displacement). The flow varies according to the Diesel RPM. From charge pressure pump, oil flows to the DA valve. The calibrate orifice O creates a restriction to the flow resulting in pressure at the inlet of the valve. Higher RPM creates an higher force at the bottom of the spool due to the increasing flow. At the outlet of the restrictor, oil flows to the charge pressure relief valve. The pilot pressure PS depends on the position of the spool controled by the charge flow. From the DA valve, outlet PS pressure is then directed to the servo-control valve. THE DA VALVE CONTROLS THE PILOT PRESSURE PS WHICH

CP

OPERATES THE SERVO-CYLINDER. PS PRESSURE DEPENDS ON DIESEL RPM.

D

The curve below shows an exemple of PS pressure according to the Diesel engine RPM (N=RPM from idle to full revolutions)

PS

Vg max

P 35

O

30

25 C PS

20 18

D

15

10 PS 6 5

28 N (RPM)

CP

The curve C shows the charge pressure, the pilot pressure PS, Vg is the displacement of the main pump according to the pilot pressure PS. The pilot pressure in idle mode is not able to operate the swash plate, due to the calibrated springs installed into the servo-cylinder. The main pump start to operate with a PS pressure of 6 bar. The maximum swash plate angle require 18 bar of PS pressure.



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4 - SWASH PLATE OPERATION

T

P

B92

B93

r a b 2 Y1

b R

B m m 8. 0

A m m 8. Y2

0

a

T2 T1

PS

Fa2

Fa1

Fe

Mb

B

470 bar

470 bar

28 bar

440 bar

A

X1

X2

G

Mh

S

Ma

2 mm

HPa 3 Tramming forward is selected, note the pressure which enters at the control portY1. Not using the inching pedal, the servo-control is fully moved in forward position. PS pressure is directed to the servo-cylinder. • engine in idle, the swash plate cannot be operated, there is no flow out of the pump, the machine does not move. The pilot pressure PS is lower than 6 bar. • by increasing step by step the Diesel RPM, the PS pressure can star t to move the swash plate, the tramming speed will increase step by step. When the swash plate is operated, oil flows to the main HP line A. The check valve at the HPa relief valve is closed due to the higher pressure applied from line A.



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1.4

servo-control operation

SWASH PLATE

DRIVING KEY

SERVO-VALVE

SERVO-CYLINDER

IMPORTANT NOT TO CONFUSE BETWEEN

PS PRESSURE IS THE PRESSURE CONTROLLED CONTROL PRESSURE IS THE PRESSURE

BY THE DA VALVE. IT VARIES ACCORDING TO THE DIESEL RPM

SENT BY THE OPERATOR IN Y1 OR Y2 TO SELECT TRAMMING DIRECTIONS.

CHARGE PRESSURE FLOWS TO THE TRAMMING DIRECTION VALVE, (SOLENOID Y82 / Y83).THE INCHING PEDAL REDUCES THIS CONTROL PRESSURE WHEN DEPRESS.



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AXLE TYPE, TRAMMING CIRCUIT NEUTRAL POSITION

Y1

SERVO-VALVE

Y2

SERVO-CYLINDER In neutral position : the swash plate is perpendicular to the pump axis, the servo-valve releases both area of the cylinder to tank. TRAMMING SIGNAL TO THE SERVO-VALVE when reduces by the inching pedal and Diesel at full RPM

Y1

Y2

The control pressure in Y2 moves the spool upward expending the spring. PS Pilot pressure is directed to the servocylinder. The swash plate shifts.



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AXLE TYPE, TRAMMING CIRCUIT CONTROL OF THE SWASH PLATE ANGLE

Y1

Y2

As soon as the servo-cylinder moves, the mechanical linkage expend the sring in the opposite direction of the control tension given by the control pressure inY2. The cylinder moves until the spring is fully equalized. When fully balanced, the spool returns to neutral position. A low control force (in ports Y) results in a small cylinder stroke. The angle of the swash plate can be accurately monitored according to the control pressure. The Diesel engine at full revolutions, the operator keep total control of the speed by using the inching pedal.

It is therefore possible to run the engine at high revolutions moving the machine slowly and using at the same time another pump. In this situation, most of the engine power is a left available by the tramming circuit to other functions.


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DIESEL ANTI-STALLING HP re-acting force. OF

B

X1 R

X2

Y2 HP.B

PS

OF T2

DA

MB

MA

CP G

HP.A

For better matching the Diesel engine power the high pressure pistons pushes the swash in opposite side as the servo-cylinder. There is a re-acting force from the swash plate against the servo-piston force. An higher working pressure results in an higher re-action force. When the engine start to run overloaded, it looses RPM. The pilot pressure PS drops due to the DA valve. At the same time the running pressure is high, the re-action force will assist the pump to "destroke" automatically. The tramming is now running at full pressure in lower flow. The power requested to the engine is reduced. The distributor plates is offset to achieve this re-action force. NO OFFSET

OFFSET PLATE

With no offset, from each side of the swash plate the piston balances themselves. By rotating the distributor plate, we can move the last pressured piston further in one side. The swash plate is no longer balanced. The distributor plates receives an offset by machining the locking groove with a preset offset angle. CAUTION : see top drawwing, the same distributor plate can be used with pump running clockwise or C.C.Wise.

OF

An adjusting offset screw allows minor adjustment from factory presetting. The noch on the adjusting screw shows the adjustment. When parallel to the pump axis there is the minimum offset. Adjustment can be from 90° in either direction. SANDVIK TAMROCK SECOMA S.A. 19 avenue De Lattre-de-Tassigny - ZI B.P. 46 - 69881 MEYZIEU Cedex Tel : (33) 472 45 22 00 F ax : (33) 478 31 79 80

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H.P. CONTROL VALVE 3, BACKWARD MOTION SHOWN - HP IN LINE A.

3-1

1

3-2

M H

2 This valve includes a selector spool 3-2. According to the tramming direction, the HP (here in line A) pushes the spool 3.1 upward. Since the tramming pressure do not reaches 440 bar, PS pressure stays at the level produced by the DA valve. After this level of HP pressure, the valve 3 opens. PS pressure drops. Therefore the swash plate moves, reducing the outlet flow. The flow is automatically adjusted to maintain the HP at a maximum of 440 bar. The re-acting force help to return the swash plate to lower displacement.

CHECK & ADJUSTMENT PUT THE MACHINE ON STABILIZERS, NO WHEELS IN CONTACT TO THE GROUND MAKE SURE OIL IS AT CORRECT TEMPERATURE 60°C APPLY EMERGENCY / PARKING BRAKES PLACE A 600 BAR GAUGE AT THE HP TRAMMING TEST POINT SELECT: HIGH-SPEED MODE THEN ONE TRAMMING DIRECTION INCREASE DIESEL RPM TO FULL REVOLUTION, THE GAUGE SHOULD SHOW 440BAR ADJUST THE VALVE 3, IF NOT CORRECT CHECK THE PRESSURE IN OPPOSITE DIRECTION



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AXLE TYPE, TRAMMING CIRCUIT Detail of the HP contrl valve together with its circuit-selctor valve.

E D

A

B C

The drawing shows now the forward motion. HP oil enters the selector valve from chanel A. The selector spool moves downward pluging the lower chanel C. The pressure increases to 440 bar, setting of the valve. The force crated at the bottom of the pusher D can now compress the spring. The pusher and the spool E.move upward. PS pilot pressure drops to tank. Therefore the swash plate moves back, the pump "de-strokes" THE PUMP WORKS NOW IN PRESSURE MAINTAIN MODE


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1.5

Hydraulic braking

1.5.1


Machine is moving downhill, to reduce speed the operator leave the accelerator pedal, engine reduces RPM.

b R

a

T2 T1

PS

Fa2

Fa1

Fe

Mb B

470 bar

470 bar

28 bar

440 bar

A X1

X2

G

Mh

S

Ma

Oil runs from line A to line B. The machine moving downward, the hydraulic motor works as a pump. REMINDER : PUMP FLOW =

RPM *

DISPLACEMENT

When the operator releases the accelerator, Diesel engine drops in RPM, the pump reduces flow by two ways: • due to reduced RPM • referring to pump working principle, low RPM results as well in PS pressure drop. Therefore the displacement of the pump reduces. The flow running through the pump is reduced. The pump creates a restriction to the flow, pressure in lineB increases creating a back pressure at the motor outlet. The tramming speed is reduced.



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1.5.2

MAXIMUM BRAKING CAPABILITY 470bar b R

a

T2 T1

PS

Fa2

Fa1

Fe

Mb B

470 bar

470 bar

28 bar

440 bar

A X1

HPb

X2

G

3

Mh

S

Ma

Tramming condition: • machine is moving downward at normal speed in such situation • the operator put the tramming direction switch to neutral The servo-control valve moves to neutral position, PS pressure is no longer directed to the servo-cylinder. Spring place the swash plate back to neutral. No oil is able to flow through the pump. Due to the kinetic energy (weight of the machine and downward speed ) the motor is still running. The pressure quickly increases in line B. It operates the HPb relief valve, pressure reaches 470bar. The tramming motor is now at its maximum torque to stop the machine. Note that the maximum torque in tramming conditions is 440bar controls by the valve3. Therefore the braking torque is higher than the tramming torque. This ensures that if the machine claim an incline, the tramming system get higher braking capability to stop the machine.


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1.6

Safety braking circuit b R

a

T2 T1

PS

Fa2

Fa1

Fe

Mb B

470 bar

DIESEL 470 bar

28 bar

440 bar

A X1

X2

G

Mh

S

Ma

2mm

9

10 b

1

2

P

3 10

11

12

13

T A

front

rear

BRAKES

NORMAL TRAMMING CONDITIONS

operator pulls the brakes control valve 13. Charge pressure is directed through the sequence valve 12 to the brake cylinders. Charge pressure releases the brakes. EMERGENCY SITUATION

In the event of one of the main H.P. hoses is damaged, oil is leaking to the ground. Most of the charge oil will flow through HPb check valve to the pump and through HPa check valve to the damaged hose then to the ground. There will be a large drop in charge pressure. When charge pressure drops below 12 bar the sequence valve will automatically shifts back to neutral. The pressure from the brake cylinders is released, BRAKES ARE APPLIED AUTOMATICALLY. NOTE: when the tramming components are worn out, the internal leakage increases. While tramming the charge pressure can drop due to excess of internal leakage. The brakes can be applied in such conditions. When the charge pressure is fluctuating around the sequence valve setting, this valve will move from neutral to open position according to the charge pressure. Brakes cylinders will be pumping; the final result is a fatigue of the brake springs therefore a drop in braking efficiency.


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PREVENTIVE MAINTENANCE

Perform a tramming component test during each weekly maintenance. • WARNING install a 600b gauge at the H.P. test point, raise the machine using stabilizers. • select high-speed mode and one tramming direction • push the brakes valve red button to apply the brakes, run the engine at full RPM. The 600b gauge should indicate 440b in either tramming direction The charge pressure should be higher than 12b. A lower charge pressure indicates large internal leakage calling for component replacement. ACCELERATOR CIRCUIT

From pump port G, charge pressure is also directed to the accelerator circuit. Components: • 11: pressure reducer • 10: accelerator pedal • 9: hydraulic accelerator cylinder The accelerator cylinder is working at a maximum pressure of 10 bar. From the charge line oil is directed first to the pressure reducer 11. 10 bar reduced pressure supplies oil to the pedal 10. By pushing on the pedal a pilot pressure is directed to the cylinder 9. The pedal outlet pressure depends on the position of the pedal. The cylinder stroke will depend on the outlet pressure.


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1.7

Hydraulic motor

Variable displacement type, bent axis. 15

U

B

X1

X2

16

18

M1

M1

B

A

G

T

M1

A

B

T

17 X1

X2

U

T G

X3

16 M1

17

15

3 G X

Hydraulic motor ports and components • A and B, main line inlets • T case drain port. NOTE: drain line should be connected to the top drain port to keep the motor housing full of oil. This line is directed to the air cooler • G high pressure test point • X1 and X2, connected to the pump port X1 and X2, lines which operate the servo-cylinder • M1 swash plate cylinder test point • 15 circuit selector valve 16 swash plate cylinder • 17 control valve

18 flushing circuit valve SANDVIK TAMROCK SECOMA S.A. 19 avenue De Lattre-de-Tassigny - ZI B.P. 46 - 69881 MEYZIEU Cedex Tel : (33) 472 45 22 00 Fax : (33) 478 31 79 80


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1.7.1


15

U

B

X1

X2

M1

17

A

G

T

17 3 G X

The operator activates: • select high-speed mode • forward direction • push the accelerator pedal fully to get full Diesel RPM

HYDRAULIC POWER • flat ground means, low torque needed by the motor then low tramming pressure; pump runs at full flow • engine is kept at full RPM; the PS pressure is then maximum

HYDRAULIC MOTOR CIRCUIT • forward direction selected means that PS pressure is directed to line X1 • the circuit selector 15 is maintained in the position shown • PS pressure from X1 flows through the valve 15 to operate the control valve 17. • high pressure from line A flows through the selector valve 15 to the valve 17. At the control valve 17, PS pressure is acting on a large pilot chamber, the HP pressure is acting together with the adjustable spring on the opposite side in a smaller pilot chamber. In this tramming condition, PS force is higher than HP force + spring force. The valve moves as shown. High pressure flows to the large chamber of the cylinder. The motor reduces displacement, the speed increases, torque reduces.


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1.7.2

UPWARD IN AN INCLINE

The operator keeps all controls as previously. Accelerator is still fully down. 15

U

B

A

X1

G

X2

M1

T

17

3 G X

HYDRAULIC POWER • incline means, high torque needed by the motor then high tramming pressure. • engine must be kept at full RPM; the PS pressure is then maximum

HYDRAULIC MOTOR CIRCUIT: The HP pressure is now increasing. At the control valve 17 the balance of force becomes: HP force + spring force > (higher than) PS force. The valve moves back to neutral as shown. The large area of the cylinder is vented to tank through a restrictor for smooth swash plate motion. The motor moves to maximum displacement, highest torque.If the decline is maximum calling for very high tramming pressure (300 bar to 350 bar) the Diesel can be overloaded. To reduce the power demand from the tramming circuit at maximum HP pressure, the pump reduces outlet flow to maintain the Diesel closed to maximum RPM. REMINDER : IN MAXIMUM INCLINE THE MOTOR MOVES FIRST TO LARGE DISPLACEMENT, THE PUMP "DESTROKE" ITSELF AFTERWARD

MEDIUM PRESSURE

According to the tramming conditions, the motor can move from full to minimum displacement. 3 G X



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LOW RANGE LOCKING DEVICE

The operator activates: X2

• low-range mode, solenoids B01 and B02 are not energized

X1 B

A

T

P

B01

B

A

T

P

• forward direction • push the accelerator pedal fully to get full Diesel RPM

B02

HYDRAULIC MOTOR CIRCUIT

15 U

B

X1

X2

M1

In any tramming condition, the motor will be maintained in maximum displacement. The solenoid valve plugs PS pressure from the pump in line X1. Lines X1 and X2 from the motor are both vented to tank. The circuit selector-valve 15 stays as shown. The control valve 17 keeps the position shown due to the HP pressure applied on one side of the spool + the spring. The large area of the cylinder is maintained released.

A

G

T

The motor stays in maximum displacement, highest torque. 17

Gauge G shows HP pressure BACKWARD TRAMMING

The operator activates: • low range mode, solenoids B01 and B02 are not energized

X2

• backward direction

X1

U

B

A

T

P

B

B01

B

A

T

P

X1

X2

• push the accelerator pedal fully to get full Diesel RPM B02

M1

HYDRAULIC MOTOR CIRCUIT The solenoid valve B02 plugs PS pressure from the pump in line X2. Lines X1 and X2 from the motor are both vented to tank. From forward circuit, valves 15 and 17 stay in the same position. HP is now in line B. Line A get charge pressure. Therefore the cylinder is now maintain is maximum displacement by the charge pressure. Gauge G shows charge pressure.

A

G

T

NOTE: the tramming HP test point located at the tramming compartment is connected to G port. Due to the low range device, for checking forward and reverse maximum tramming pressure, the speed selector must be place in high-speed mode (solenoids B01 & B02 energized).

!

WARNING: For safe tramming, the low range mode must be

selected in decline.



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1.8

Hydrostatic braking 11

19

4

Charge pressure supplies oil to the inching pedal 19. In neutral, a spring maintains the hydraulic cartridge is fully engaged position. Full charge pressure is supplied to the "Forward/backward solenoid control valve"11. When direction is selected servo-control valve 4 is therefore fully operated.

While tramming, if the operator wants to reduce speed or stop the machine, he releases the accelerator pedal then he pushes on the inching pedal 19. The pilot pressure directed to the servo-control valve 4 through the solenoid valve 11 is reduced. Less pilot pressure is directed to the servo-cylinder resulting in a reduced flow at the outlet of the pump. The speed of the machine is reduced. If the operator wants to stop the machine, he pushes the pedal fully. Pilot pressure drops to 0. No more pressure is acting within the servo-cylinder. The pump moves back to neutral. No flow runs through the pump. Time to stop the machine, the hydraulic motor runs as a pump. The flow from the motor can only circulate through the HP relief valve until complete stop. (see: paragraph maximum braking capability page 20).


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1.9

Hydrostatic & emergency automatic braking.(option)

S

V The hydrostatic circuit bring the machine to complet stop in any tramming conditions. In declines, after complet stop, due to internal leakages at the motor and at the pump, the wheel are "crimping". The operator should apply the emergency/parking brakes.

The option describe in the above schematic, applies the parking brakes automatically. The outlet of the selector valve S directs the control pressure to the sequence valve V set at 5 bar. The operator pushes the inching pedal to stop the machine. The control pressure at the outlet of the tramming direction valve Y92 / Y93 drops. The machine stops due to the hydrostatic braking. When the control pressure drops to 5 bar, the sequence valve V shifts to aplly the brakes. Note the 2.5mm orifice allows the brakes to be applied softly.





1.10 11

Mechanical braking (option) 19

4


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AXLE TYPE, TRAMMING CIRCUIT ) P5

• P1: unloading valve, P2: pressure switch, P3: accumulator, P4: brake pedal, P5: brake actuator BRAKING CIRCUIT

P4

P2

P3

From the pump oil is directed to the unloading valve. Note the safety relief valve set at 200bar on the line from the pump. When the accumulators are low in pressure, the circuit is as shown. Oil flows through the unloading valve to both accumulators and to the inlet of the pedal. Note that there is two separate lines for front brakes and rear brakes. Each one includes their own: • pilot control unit (within the unloading valve), accumulator, pressure switch, hydraulic control cartr idge (within the pedal)

P1

When both accumulators are fully charged, the flow from the pump is released to the tank by the first spool of the unloading valve. MAINTENANCE

Every monthly maintenance, check the accumulator loading cycles. • Not use the brakes • ¨Place a gauge at the outlet line from the pump as shown. If there is less than 5 minutes in between two charging cycles, accumulators must be inflated or repaired.


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1.11

ABA brakes (option)

t

r or

er

From the pedal braking circuit the only difference is two extra pressure switches E58 and E59. a

n f

A

A

ABA safety brake circuit P

T

P

T

E100

E101

P E59

E57

P

P

L L 1 1

E56

E58

P

P

B91 A1

P

B92

A2 SW

E36 P

front P

rear

T

BRAKES ELECTRICAL FUNCTION Pressure switches E56 & E57 turn light OFF when both are pressurized over 110 bar.

200

0 1

When the safety brakes are applied, no pressure in the actuators as shown, pressure switch E36 turns light ON and allows the used of the engine starter. To start Diesel engine the Safety/Park brakes must be ON. To release the Safety/Park brakes, it is needed: • pull up the electric button at the ABA control box

• To make sure that both accumulators are at 75 bar minimum pressure; both pressure switches E58 & E59 must be pressurized • Pressure switch E100 ensures that charge pressure, which operates the emergency/park brake, is at a minimum of 10 bar. If the pressure at any of those 3 pressure switches is below the required level of pressure, , the solenoid valves B91 and B92 apply the Safety/Park brakes. NOTE: Pressure switch E101 turn a warning light ON to warn the operator that the safety brakes can be applied soon. The light glows when the charge pressure drops below 15 bar.



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WHEEL MOTORS

MODULE 2) 2.1

WHEEL MOTORS

principle

AVANT FRONT

R

L

L

R

E H T C F U E A L G

E T T I H O G R I D R

R

L

L

R

A

B

ARRIERE REAR


TR_Tram_EN

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