- Load Haul Dump:
- R2900G (S/N: JLK865-UP)
The hydraulic schematic for the ride control system has incorrect information. Replace the information with the following information.
Ride Control System
S/N: JLK865-UP
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| Illustration 1 | g01515694 |
Schematic for the hydraulic system (1) Main control valve (2) Line relief valve for rod end of tilt cylinder (3) Line relief valve for head end of tilt cylinder (4) Pressure tap for rod end of tilt cylinder (5) Tilt cylinder (6) Lift cylinders (7) Ride control accumulator (8) Ride control diverter valve (9) Pressure tap for head end of tilt cylinder (10) Lift circuit relief valve (11) Ride control relief valve (12) Implement and steering solenoid valve (13) Ride control solenoid valve (14) Main relief valve (15) Parking brake solenoid valves (16) Parking brake oil pressure switch (17) Pressure tap for the parking brake circuit (18) Check valve (19) Lift arm positioner valve (20) Float sequence valve (21) Line circuit remote control (22) Selector and pressure control valve (23) Line to parking brakes (24) Line from steering circuit (25) Pilot control valve (26) Brake accumulator charging valve (27) Breaker relief valve (28) Check valve (29) Portable hydraulic pump quick connect coupler (30) Line to brake accumulator (31) Pilot and braking pump (32) Steering pump (33) Implement pump (34) Hydraulic filters (35) Hydraulic tank (36) Pilot relief valve (37) Pilot system pressure tap (38) Pilot oil filter (39) Check valve (40) Portable hydraulic pump quick connect coupler | |
The ride control system provides a means for dampening the bucket forces which produce a pitching motion as the machine travels over rough terrain.
The main components of the ride control system are ride control accumulator (7), ride control diverter valve (8), ride control solenoid valve (13) and lift cylinders (6).
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| Illustration 2 | g01138933 |
(7) Ride control accumulator | |
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| Illustration 3 | g01040086 |
(8) Ride control diverter valve (13) Ride control solenoid valve | |
Ride control accumulator (7) is mounted in the left side of the front frame. Ride control diverter valve (8) and ride control solenoid valve (13) are mounted under the cover on the front frame of the machine.
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| Illustration 4 | g01519473 |
(41) Ride control switch (42) Ride control indicator | |
Ride control switch (41) is mounted in the switch panel in the operator station. Ride control indicator (42) is located on the indicator panel in the operator station.
When the ride control system is activated, the head end of the lift cylinders are connected to ride control accumulator (7). The ride control accumulator provides a cushioning effect to the head end oil, allowing the lift cylinders to extend and retract slightly. The bucket can move as a balance weight against the movement of the machine.
Ride control switch (41) has three positions: the OFF position, the AUTO position and the SERVICE position.
OFF Position
Ride control solenoid valve (13) is a normally closed valve. When the lift spool in main control valve (1) is in the HOLD position and ride control switch (41) is in the OFF position, the coil in ride control solenoid valve (13) is not energized. A spring in the ride control solenoid valve holds the solenoid valve spool in the closed position. With the solenoid valve spool in the closed position, the ride control system will not operate.
When the ride control switch is in the OFF position, the check valve between lift cylinders (6) and ride control accumulator (7) allows a continual sensing of the lift cylinder pressure. When a load is in the bucket, pressure increases in the head end of the lift cylinders. This pressure passes through the check valve into ride control accumulator (7) to compress the nitrogen charge. This prevents the bucket from moving when the ride control system is activated.
AUTO Position
When ride control switch (41) is moved to the AUTO position, the ride control system will automatically activate when the machine ground speed exceeds 5 km/h (3 mph). Ride control indicator (42) will illuminate when the ride control system is activated.
When the lift spool is in the HOLD position and ride control switch (41) is moved to the AUTO position and the ground speed of the machine exceeds 5 km/h (3 mph), the coil in ride control solenoid valve (13) is energized. When the solenoid valve coil is energized it causes the solenoid valve spool to move against the spring force to the OPEN position.
When ride control solenoid valve (13) is in the OPEN position, pilot oil can now act on the right side of the spool in ride control diverter valve (8) and moves the spool to the left. The lift cylinder head end oil is now open to ride control accumulator (7) and the lift cylinder rod end oil is open to hydraulic tank (35) .
As the machine moves across rough terrain with a loaded bucket, the forces of the load act against the lift cylinders and the oil in the head end of the lift cylinders. The oil in the head end of the lift cylinders is felt at ride control accumulator (7) .
Ride control accumulator (7) has a nitrogen precharge that resists the head end oil pressure and acts as a shock absorber.
SERVICE Position
The SERVICE position is used for testing and troubleshooting the ride control system.
When ride control switch (41) is moved to the SERVICE position, the ride control system will be activated. Ride control switch (41) will return to the OFF position when released. Ride control indicator (42) will illuminate when the ride control system is activated.
When ride control switch (41) is moved to the SERVICE position, the ride control system operates the same as "AUTO Position" except that the system is activated regardless of ground speed.