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| Illustration 1 | g06091675 |
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(1) Standard motor
(2) Line from gear pump (3) Line for case drain (4) Outlet port for the motor (5) Demand fan solenoid valve | |
Hydraulic motor (1) is a gear-type motor. The motor is located behind the radiator. The hydraulic motor drives the radiator fan. The fan draws cooling air through the radiator and the hydraulic oil cooler. Hydraulic oil for the hydraulic motor is provided by the gear pump.
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| Illustration 2 | g01083456 |
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(1) Standard motor
(2) Line from gear pump (3) Line for case drain (4) Outlet port for the motor (5) Demand fan solenoid valve (6) Makeup valve (7) Orifice (8) Flow control valve for the fan | |
When the machine is started, oil flows into hydraulic motor (1) from pump line (2). The hydraulic oil flows into a cavity that is formed by gears. The pressure of the hydraulic oil forces the gears and the output shaft to rotate.
The fan is attached to the output shaft by an adapter. The rotation of the output shaft causes the fan to rotate. As the gears rotate, the hydraulic oil passes through outlet port (4) and the oil flows out of the motor.
The hydraulic motor is equipped with demand fan solenoid valve (5), flow control valve (8) and makeup valve (6). The demand fan solenoid valve is controlled by the machine ECM. The machine ECM sends a signal to the demand fan solenoid valve to control the speed of the fan. When the machine ECM sends a maximum signal to the demand fan solenoid valve, the pressure drop across orifice (7) will increase and flow control valve (8) will open. The fan speed will be at the minimum because the flow control valve is diverting oil flow from the pump around the motor. When the machine ECM sends a minimum signal to the demand fan solenoid valve, the pressure drop across orifice (7) will decrease and flow control valve (8) will close. The fan speed will be at the maximum because the flow control valve is no longer diverting oil flow around the motor.
The machine ECM will send the required signal to the demand fan solenoid valve to provide the proper fan speed for the cooling system. The machine ECM will monitor the following parameters to provide the proper fan speed:
- Coolant temperature
- Hydraulic oil temperature
- Transmission oil temperature
- Air inlet temperature
Makeup valve (6) prevents cavitation in the hydraulic motor. During a quick deceleration, the flow of oil to the motor can stop. The makeup valve will open. This allows oil to flow from the outlet side of the hydraulic motor to the inlet side of the motor.
Case drain (3) drains oil from the motor to the tank.