 | |
| Illustration 1 | g01114200 |
Multi Terrain Loader hydrostatic system (1) Pilot Valve (hydrostatic system) (2) Solenoid Valve Group (hydrostatic system) (3) Resolver network (4) Piston Motor Group (hydrostatic left side) (5) Solenoid Valve and Mounting Group (parking brake) (6) Piston Motor Group (hydrostatic right side) (7) Pump actuator group (hydrostatic left side) (8) High pressure port for the "B" loop (9) Pump actuator group (hydrostatic right side) (10) High pressure port for the "B" loop (11) "X3" Pilot pressure port (hydrostatic left side) (12) "X4" Pilot pressure port (hydrostatic left side) (13) High pressure port for the "A" loop (14) "X3" Pilot pressure port (hydrostatic right side) (15) "X4" Pilot pressure port (hydrostatic right side) (16) Relief Valve (Charge oil) (17) Speed Sensing Valve Group (18) High pressure port for the "A" loop (19) Piston Pump (hydrostatic system) (20) Gear Pump (21) Hydraulic Tank Gp | |
The hydrostatic system is made up of the following main components: Hydraulic Tank Gp (21), Gear Pump (20), Piston Pump (hydrostatic system) (19), Piston Motor Group (hydrostatic right side) (6) and Piston Motor Group (hydrostatic left side) (4) .
The hydrostatic system is a closed loop. The oil that flows from the Piston Pump (hydrostatic system) to the Piston Motor Groups (hydrostatic system) then back to the Piston Pump (hydrostatic system) flows in a continuous loop. The hydrostatic system is kept full of oil by the charge system. The second section of the gear pump supplies both sections of the Piston Pump (hydrostatic system) with charge oil.
 | |
| Illustration 2 | g01063129 |
Components in the Multi Terrain Loader hydrostatic system (21) Hydraulic Tank Gp (20) Gear Pump (charge oil, implement, air conditioner and fan drive) (19) Piston Pump (hydrostatic system) (6) Piston Motor Group (hydrostatic right side) (4) Piston Motor Group (hydrostatic left side) | |
Pilot oil flows from the Pilot Valve (hydrostatic system) (1) to the pilot pressure port (11), pilot pressure port (12), pilot pressure port (14), and pilot pressure port (15) that are on the Piston Pump (hydrostatic system). The pilot oil causes the pump actuator (7) and pump actuator (9) in the Piston Pump (hydrostatic system) to move the swashplates. This causes the Piston Pump (hydrostatic system) to pump oil to piston motor (4) and piston motor (6) .
When the Piston Pump (hydrostatic system) is in the NEUTRAL position only charge pressure will flow to the piston motors from port (18), port (10), port (13), and port (8). The charge oil pressure is 3800 ± 350 kPa (550 ± 50 psi) at engine HIGH idle. The engine high idle speed is 2860 ± 50 rpm. The charge oil pressure is 3200 ± 200 kPa (465 ± 30 psi) at engine LOW idle. The engine LOW idle speed is 1000 ± 50 rpm.
In the NEUTRAL position, no high pressure oil flow is provided to the piston motors. The hydrostatic system oil pressure will be equal to the charge oil pressure.
If the travel control lever is pushed to the FORWARD position, Pilot Valve (1) opens a path for the oil to flow to the pump actuator (4) and to pump actuator (6). The oil that flows into pilot pressure port (15) causes the actuator piston (6) to shift left. The pilot oil also flows into pilot pressure port (12). The pilot oil that flows into pilot pressure port (12) causes the actuator piston (4) to shift left.
The movement of the actuators causes the swashplates to move. Movement of the swashplate will cause piston pump (19) to upstroke. The flow of the oil out of port (13) and port (18) increases. Refer to the Systems Operation, RENR4877, "Pilot Hydraulic System" for additional information about the pilot valve. Refer to Systems Operation, RENR4877, "Piston Pump (Hydrostatic System)" for additional information about the piston pump.
The oil that flows out of the port (18) to piston motor (6) is drive loop "A". The oil that flows out of the port (13) to piston motor (4) is drive loop "B". Both drive loops exit piston pump (19) through ports that are identified as "A".
The oil that flows out of port (18) and port (13) causes piston motor (5) and piston motor (4) to rotate. The shafts of the piston motors will turn at a rate that is determined by the amount of oil that is flowing to the piston motors. If the travel control lever is moved further into the FORWARD position, the swashplates will move further. This causes the piston pump (19) to pump oil to the piston motors at a greater flow rate. If the flow rate is greater, the shafts of the motors will turn faster. Refer to Systems Operation, RENR4877, "Piston Motor Group" for additional information.
The oil that is flowing from the piston motors to piston pump (19) is at a lower pressure. The lower pressure oil returns to the piston pump through port (10) and port (8). Any oil that is lost from the drive loop"A" or drive loop "B" is replaced by charge oil.