The optional ride control system provides a means for dampening the bucket forces which produce a pitching motion as the machine travels over rough terrain. The precharge of nitrogen gas in the accumulator supplies the cushion.
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| Illustration 1 | g00835799 |
Location of the Ride Control Switch in the Control Panel | |
Ride control is initiated by the ride control switch. The ride control switch is a three-position switch that is located in the control panel on the right side of the cab.
The ride control system is made up of the following components: the lift cylinders, the ride control diverter valve, the ride control accumulator, the pressure balance valve and the manifold.
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| Illustration 2 | g00914354 |
Location of the Ride control System (1) Accumulator. (2) Front frame. (3) Ride control solenoid valve. (4) Main control valve. (5) Diverter valve. | |
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| Illustration 3 | g00914363 |
(2) Front frame. (5) Diverter valve. (6) Pressure balance valve. (7) Ride control check valve. | |
Ride control diverter valve (5) is located on the front frame. Ride control diverter valve (5) is attached to main control valve (4). Ride control diverter valve (5) allows oil from the head end of the lift cylinders to flow to ride control accumulator (1) .
Ride control solenoid valve (4) is a component of ride control diverter valve (5).
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| Illustration 4 | g00914381 |
Pressure Balance Valve in Balance (8) Signal port from the accumulator. (9) Passage to the hydraulic tank. (10) Passage to the Accumulator. (11) Passage to the Implement pump. (12) Signal port from the head end of the lift cylinders. | |
The pressure between the head end of the lift cylinders and the accumulator should be equalized. Pressure balance valve (6) is used in order to balance the pressure. Pressure balance valve (6) uses pilot pressure from the head end of the lift cylinders and the pressure from accumulator (1) in order to balance the pressure in the ride control system. When the pressure is balanced, no oil can flow into passage (10) or no oil can flow out of passage (10). When the pressure goes higher in accumulator (1), the stem in pressure balance valve (6) will shift to the right. Oil will flow out of accumulator (1) through pressure balance valve (6) until the pressure is equal to the pressure in the head end of the lift cylinders. When the pressure at signal passage (8) is equal to the signal pressure (12), the stem will shift to the BLOCKED position. Refer to Illustration 4 for a graphic of the two pressures in balance.
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| Illustration 5 | g00914388 |
Pressure Balance Valve with Higher Pressure in the Accumulator (8) Signal port from the accumulator. (9) Passage to the Implement pump. (10) Passage to the Accumulator. (11) Passage to the hydraulic tank. (12) Signal port from the head end of the lift cylinders. | |
When the accumulator pressure at signal port (8) is higher, the stem in pressure balance valve (6) will shift to the right. Refer to Illustration 5 for a graphic of the stem that is shifted to the right. Oil will flow out of accumulator (1) into passage (10). The oil will flow to the hydraulic tank through passage (11) until the pressure at signal port (12) is equal to the pressure at signal port (8). When the pressure at signal port (8) is equal to the pressure at signal port (12), the stem will shift to the BLOCKED position.
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| Illustration 6 | g00914392 |
Pressure Balance Valve with Higher Pressure in the Head End of the Lift Cylinders (8) Signal port from the accumulator. (9) Passage to the hydraulic tank. (10) Passage to the Accumulator. (11) Passage to the Implement pump. (12) Signal port from the head end of the lift cylinders. | |
When the pressure at signal port (12) is higher, the stem in pressure balance valve (6) shifts to the left. High pressure oil from the main hydraulic system will flow into pressure balance valve (7) through passage (9). The oil flows around the stem and the oil exits the valve through passage (10). The oil flows to accumulator (1). Refer to Illustration 6 for a graphic that shows high pressure oil from the implement pump that is flowing into accumulator (1). When the pressure at signal port (8) is equal to the pressure at signal port (12), the stem will shift to the BLOCKED position.
Ride control check valve (7) is installed between the high pressure line that is going to the main control valve and pressure balance valve (6). Ride control check valve (7) insulates any pressure spikes in the ride control system from the main hydraulic system.
Ride Control Switch in the OFF Position
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| Illustration 7 | g00914400 |
Schematic for the Ride Control System in the OFF Position (1) Accumulator. (3) Ride control solenoid valve. (5) Diverter valve. (6) Pressure balance valve. (7) Ride control check valve. (13) Lift cylinders. (14) Ball resolver. (15) Stem (diverter valve). (16) Hydraulic tank. (17) Implement pump. (18) Power train ECM. (A) Line to the pilot drain. (B) Line for the lift function. (C) Line for the lower function. (D) Line for pilot pressure for dead engine lower. (E) Pilot pressure line. (F) High pressure line to the main control valve. | |
When the ride control switch is in the CENTER position, the ride control switch is midway between the ON and AUTO positions. For the location of the ride control switch, refer to Illustration 1.
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| Illustration 8 | g00914405 |
Sectional View of the Diverter Valve in the OFF Position (3) Solenoid valve. (5) Diverter valve. (15) Stem (diverter valve). (19) Passage between the solenoid valve and the pilot chamber. (20) Chamber. (21) Chamber to the accumulator port. (22) Chamber to the port for the head end of the lift cylinder. (23) Chamber to the hydraulic tank. (24) Chamber to the port for the rod end of the lift cylinder. (25) Pilot chamber. (26) Return spring. | |
When the ride control switch is in the CENTER position, no current flows to the coil of solenoid valve (4). No pilot oil will be flowing to stem (15) of diverter valve (5). Stem (15) of diverter valve (5) is in the closed position. The oil from the head end of lift cylinders (13) is blocked from accumulator (1). There will be no cushion as the machine travels over rough terrain. Illustration 8 shows that there will be no flow of oil between accumulator chamber (21) and the chamber (22) for head end of lift cylinders (13) .
Ride Control Switch in the MANUAL Position
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| Illustration 9 | g00914409 |
Schematic for the Ride Control System in the On Position (1) Accumulator. (3) Ride control solenoid valve. (5) Diverter valve. (6) Pressure balance valve. (7) Ride control check valve. (13) Lift cylinders. (14) Ball resolver. (15) Stem (diverter valve). (16) Hydraulic tank. (17) Implement pump. (18) Power train ECM. (A) Line to the pilot drain. (B) Line for the lift function. (C) Line for the lower function. (D) Line for pilot pressure for dead engine lower. (E) Pilot pressure line. (F) High pressure line to the main control valve. | |
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| Illustration 10 | g00914412 |
Sectional View of the Diverter Valve in the Manual Mode (3) Solenoid valve. (5) Diverter valve. (15) Stem (diverter valve). (19) Passage between the solenoid valve and the pilot chamber. (20) Chamber. (21) Chamber to the accumulator port. (22) Chamber to the port for the head end of the lift cylinder. (23) Chamber to the hydraulic tank. (24) Chamber to the port for the rod end of the lift cylinder. (25) Pilot chamber. (26) Return spring. | |
When the ride control switch is moved to the MANUAL position, current flows to the coil of solenoid valve (3). Pilot oil will flow to chamber (25) through passage (19). The pilot oil that is in chamber (25) will push stem (15) of diverter valve (5). Spring (26) will be compressed. Stem (15) will shift to the left. Oil in chamber (20) will flow through the hole in the center of stem (15). The oil will flow to hydraulic tank (16). Stem (15) of diverter valve (5) is now in the OPEN position. The oil from the head end of lift cylinders (13) can flow to accumulator (1). There will be a cushion as the machine travels over rough terrain. The arrows in Illustration 10 show the oil flow between accumulator chamber (21) from accumulator (1) and chamber (23) to the head end of lift cylinders (13). Oil will flow between the head end of lift cylinders (13) and ride control accumulator (1). The precharge of nitrogen gas in accumulator (1) supplies the cushion. The oil in chamber (24) for the rod end of the lift cylinders can flow to chamber (23). The oil in chamber (23) will flow back to hydraulic tank (16).
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| Illustration 11 | g00904942 |
When the ride control switch is placed in the Auto mode, the operation of the ride control system is initiated by power train ECM (18). In Auto mode, power train ECM (18) receives an input from the transmission output speed sensors. Power train ECM (18) uses the inputs from the transmission output speed sensors in order to calculate the ground speed. When power train ECM (18) registers a ground speed of 9.6 km/h (6 mph), an output signal is sent to solenoid valve (3). Solenoid valve (3) will be energized. Solenoid valve (3) will stay energized, if the machine is traveling at a speed of 9.6 km/h (6 mph). When the ride control solenoid is energized in Auto mode, the components of the ride control system work in the same manner as if the machine is in the Manual mode.