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| Illustration 1 | g00510978 |
Hydraulic Schematic for the Ride Control System (1) Lift cylinders. (2) Ride control solenoid valve. (3) Ride control accumulator. (4) Ride control relief valve. (5) Ride control solenoid valve. (6) Lift control valve spool HOLD position. (7) Pilot selector and pressure control valve. (8) Ball valve (hydraulic lever lock). (9) Return line. (10) Hydraulic oil tank. (11) Hydraulic oil filter. (12) Implement pump. (13) Steering/pilot pump. | |
The optional ride control system provides a means for dampening bucket movement which can produce pitching during machine travel over rough terrain.
The ride control system consists of the components that follow: lift cylinders (1) , ride control solenoid valves (2) and (5) and ride control accumulator (3) .
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| Illustration 2 | g00511509 |
Ride Control Switch | |
Ride control switch (14) is mounted on the control panel to the right of the operator's seat. The control switch is a three-position switch: OFF, ON and AUTO.
Solenoid valves (2) and (5) are normally closed.
OFF Position
When lift control valve (6) is in the HOLD position and ride control switch (14) is in the OFF position, the coils inside the solenoid valves (2) and (5) are not energized. A spring in each solenoid valve holds the spools in the UP position. The head end oil of lift cylinders (1) is allowed to flow through an orifice at ride control solenoid valve (2) . The oil then flows into ride control accumulator (3) .
Rod end oil is blocked at solenoid valve (5) and at lift control valve (6) . The oil then flows through pilot selector and pressure control valve (7) . The oil then flows through ball valve (8) in order to supply pilot pressure to the implement pilot control valves.
ON Position
When lift control valve (6) is in the HOLD position and ride control switch (14) is in the ON position, the coils inside the solenoid valves (2) and (5) are energized. The spools inside the solenoid valves overcome the spring force and the spools move down. This allows head end oil to flow through ride control solenoid valve (2) and into ride control accumulator (3) . The rod end oil now flows through ride control solenoid valve (5) .
As the machine travels across rough terrain, the pitching of the load acts against the lift cylinders. When the load acts against the head end of the lift cylinders, the head end oil tries to flow through ride control solenoid valve (2) and into ride control accumulator (3) .
The piston of ride control accumulator (3) has a nitrogen precharge. The piston resists the oil flow and the piston acts as a shock absorber. Makeup oil from the rod end can flow through ride control solenoid valve (5) and through return line (9) back to hydraulic oil tank (10) .
Note: Some models are equipped with ride control relief valve (4) . If the return line pressure should exceed the setting for the relief valve, relief valve (4) would open. The oil could then flow back to hydraulic tank (10) .
AUTO Position
When lift control valve (6) is in the HOLD position and ride control switch (14) is in the AUTO position, the coils inside solenoid valves (2) and (5) are energized. As the machine approaches the load site, the operator reduces the speed of the machine. When the machine speed is reduced to approximately 9.6 km/h (6 mph), the ride control system is automatically switched off. This allows a greater breakout force.
After the bucket is filled and the operator moves the machine to the dump site, the machine speed increases. As machine speed increases to approximately 9.6 km/h (6 mph), the ride control system is switched on in order to dampen the pitching of the bucket.
Reference: For additional information about the operation of the ride control switch, refer to the appropriate Operation And Maintenance Manual for your machine.