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| Illustration 1 | g00836118 |
(1) Transmission Control (2) Mode Switch (3) Electronic Control Module (4) Filter (5) Gear Motor (Fan Drive) (6) Oil Cooler (7) Gear Pump (Fan Drive) (8) Hydraulic Tank (9) Rear Axle Differential (10) Hydrostatic Piston Pump (11) Speed Sensor (12) Drive Shaft (13) Position Sensor (Inching Pedal) (14) Hydrostatic Piston Motor (15) Front Axle Differential (16) Relief Valve (17) Transfer Gear (18) Relief Valve | |
The machine can be driven in either direction by the use of the hydrostatic drive system.
Hydrostatic piston pump (10) is driven by the engine. The hydrostatic piston pump supplies pressurized oil in order to drive hydrostatic piston motor (14). The hydrostatic piston motor is mounted onto transfer gear (17) that transmits drive to front axle differential (15). Drive shaft (12) connects the transfer gearbox to rear axle differential (9). Transmission control (1) is used to select either neutral, forward drive or reverse drive. The transmission control is also used to select high preset speed or limited preset speed. The preset speed control determines the position of the swashplate for the motor. The swashplate may be in the maximum displacement position or the swashplate may be in the limited displacement position. When the swashplate is in the maximum displacement position, the maximum motor displacement will limit the machine speed to 8 km/h (5 mph).
Mode switch (2) allows the operator to select either a travel mode or a work mode. Electronic control module (3) controls the angle of the swashplate in the hydrostatic piston pump. The electronic control module receives engine speed information from speed sensor (11). The electronic control module converts the information into a pulse modulated signal that is used to control the position of the swashplate inside the hydrostatic piston pump.
The oil flow between the hydrostatic piston pump and the hydrostatic piston motor is reduced in order to slow the machine. The application of the service brakes further slows the machine. When the brake pedal is pressed, the position sensor (inching pedal) (13) transmits a proportional signal to the electronic control module. The electronic control module sends a signal to the controller for the hydrostatic piston pump. The controller will destroke the hydrostatic piston pump in order to reduce the oil flow. The reduction in oil flow will slow the machine.
The charging system provides replacement oil and cooling oil for the hydrostatic drive system. Fan drive gear pump (7) supplies pressurized oil in order to fan drive gear motor (5). The oil then flows through oil filter (4) and into the case of the hydrostatic piston pump. The oil then flows through hydrostatic piston motor (14), oil cooler (6) and returns back into hydraulic tank (8). Relief valve (16) allows oil flow back to the hydraulic tank if the pressure within the case of the hydrostatic piston motor increases. Relief valve (18) promotes return oil flow through the oil cooler.