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| Illustration 1 | g02983164 |
Schematic for the hydraulic system. (1) Main control valve (2) Line relief valve for rod end of auxiliary cylinders (3) Line relief valve for head end of auxiliary cylinders (4) Auxiliary cylinders (5) Line relief valve for rod end of tilt cylinder (6) Line relief valve for head end of tilt cylinder (7) Pressure tap for rod end of tilt cylinder (8) Tilt cylinder (9) Pressure tap for head end of tilt cylinder (10) Lift circuit relief valve (11) Ride control accumulator (12) Ride control solenoid valve (13) Lift cylinders (14) Ride control solenoid valve (15) Line to the parking brake circuit (16) Line to the parking brake circuit (17) Main relief valve (18) Pilot diverter solenoid valve (19) Pilot diverter solenoid valve (20) Line to the pilot circuit (21) Pressure tap for the main hydraulic system (22) Pilot and braking pump (23) Steering pump (24) Lift arm positioner valve (25) Float sequence valve (26) Breaker relief valve (27) Pilot control valve (28) Check valve (29) Line from the steering valve (30) Implement pump (31) Selector and pressure control valve (32) Hydraulic oil temperature sensor (33) Line to the braking system (34) Hydraulic oil level sensor (35) Hydraulic tank (36) Hydraulic oil filters (37) Check valve (38) Pilot oil pressure reducing valve (39) Check valve (40) Implement and steering solenoid valve (41) Parking brake control valve | |
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 (11), ride control solenoid valve (12), lift cylinders (13) and ride control solenoid valve (14).
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| Illustration 2 | g02983259 |
(11) Ride control accumulator. (12) Ride control solenoid valve. | |
Ride control accumulator (11) and ride control solenoid valve (12) are mounted under the cover on the front frame.
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| Illustration 3 | g02995798 |
(14) Ride control solenoid valve. | |
Ride control solenoid valve (14) is located on the front frame of the machine by the main control valve.
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| Illustration 4 | g03463657 |
(42) Ride control switch (43) Ride control indicator | |
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| Illustration 5 | g03095336 |
Indicator lights above ride control switch. A - Left light B - Right light | |
Ride control switch (42) is mounted in the keypad in the operator station. Ride control indicator (43) is located in the instrument panel.
When the ride control system is activated, the head-end of the lift cylinders are connected to ride control accumulator (11). 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 (42) has three functions:
- OFF
- AUTO
- SERVICE
OFF
Ride control solenoid valve (12) and ride control solenoid valve (14) are normally closed valves.
When the lift valve spool in main control valve (1) is in the HOLD position, and the ride control is in the OFF mode, the coils in ride control solenoid valve (12) and ride control solenoid valve (14) are not energized.
The solenoid valve spools are held in the closed position via a spring in the ride control solenoid valves. With the solenoid valve spools in the closed position, the ride control system will not operate.
With the ride control OFF, the orifice between lift cylinders (13) and ride control accumulator (11) continually sense lift cylinder pressure. When a load is in the bucket, pressure increases in the head end of the lift cylinders. Pressure passes through orifice into ride control accumulator (11) to compress the nitrogen charge preventing bucket moving when the ride control system is enabled.
AUTO
When the ride control system is in the AUTO mode, the ride control system will enable when the machine ground speed exceeds 5 km/h (3 mph). Ride control indicator (43) will illuminate when the ride control system is enabled. In Auto Mode – Indicator (B) is ON. When, Auto Mode is Disabled – Indicator (B) is OFF.
When the lift valve spool is in the HOLD position, the ride control is in the AUTO mode and the ground speed of the machine exceeds 5 km/h (3 mph), the coils in ride control solenoid valve (12) and ride control solenoid valve (14) are energized. The energized coils cause the solenoid valve spools to move against spring force and open.
When ride control solenoid valve (12) is open, lift cylinder head end oil is open to ride control accumulator (11). When ride control solenoid valve (14) is open, 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 lift cylinders. The forces also act against oil in head end of lift cylinders. The oil in the head end of the lift cylinders is felt at ride control accumulator (11) .
Ride control accumulator (11) has a nitrogen precharge that resists the head end oil pressure and acts as a shock absorber.
SERVICE
The SERVICE mode is used for testing and troubleshooting the ride control system.
Pressing and holding ride control switch (42) enables the SERVICE mode function of the ride control. Ride control indicator (43) will illuminate when the ride control system is enabled. In Service Mode – Indicator (A) and (B) are ON.
Releasing the ride control switch, or the parking brake will disable the SERVICE mode. The ride control will return to the state prior to entering the service mode.