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| Illustration 1 | g06100102 |
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(1) Hydrostatic motor
(2) Displacement control valve (3) Flush control valve (4) High-pressure relief valve (Port B) (5) High-pressure relief valve (Port A) (6) Charge filter (7) Pressure switch for the charge filter (8) Hydrostatic charge pump (9) Hydrostatic pump (10) Proportional solenoid (reverse) (11) Proportional solenoid (forward) (12) Servo piston for hydrostatic pump (13) Flush relief valve (14) Servo piston for hydrostatic motor (M4) Servo port (M5) Servo port | |
| CCW Pump Rotation | ||
| Servo Port | M5 | M4 |
| Port A Flow | Out | In |
| Port B Flow | In | Out |
| Travel Direction | REV | FWD |
The main components of the hydrostatic drive system are hydrostatic pump (9) and hydrostatic motor (1). The hydrostatic motor is a single bent axis type motor. The pump and the motor are connected to each other at the pressure side and the return side. This system is a closed loop circuit.
The hydrostatic pump is a variable displacement piston pump. The hydrostatic motor is a single bent axis type motor with variable displacement.
The swashplate angle of the pump determines the direction of travel for the machine.
The machine electronic control module (ECM) controls the hydrostatic drive system. The machine ECM uses electrical inputs from the forward and reverse travel pedals to control the hydrostatic drive system .
The parameters of the machine ECM software optimize the operation of the hydrostatic drive system. The machine ECM reads all the input signals and compares the input signal to the set of parameters in the software. Then, the ECM generates output signals. The output signals regulate the components of the hydrostatic drive system.
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| Illustration 2 | g06122332 |
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(10) Proportional solenoid (reverse)
(11) Proportional solenoid (forward) | |
When, the operator depresses the pedal an electrical signal is sent to the machine ECM. The machine ECM processes the electrical signals from the pedal. Then, the ECM sends an electrical signal to proportional solenoids (10) or (11). An electrical signal to proportional solenoid (10) causes the machine to move in the reverse direction. An electrical signal to proportional solenoid (11) causes the machine to move forward.
The hydrostatic pump will begin to upstroke when the electrical signal that is sent to the proportional solenoids reaches the minimum current. This action causes the swashplate to tilt. As a result, oil flows from the hydrostatic pump to the hydrostatic motor .
The hydrostatic pump produces the minimum displacement when the electrical signal to the proportional solenoids is at the minimum current. The pump produces the maximum displacement when the electrical signal to the proportional solenoids is at the maximum current.
The oil from the hydrostatic pump causes the hydrostatic motor to rotate. The rotation of the hydrostatic motor depends on the swashplate angle in the hydrostatic pump.