초록 ▼

A hydraulic motor drives the cooling fan of an internal combustion engine. Fluid flow from a fixed displacement pump is directed through a pilot-operated pressure-compensated control valve to the hydraulic motor. The valve has a continuous bias to a fan-on position for directing fluid to the fan mot

A hydraulic motor drives the cooling fan of an internal combustion engine. Fluid flow from a fixed displacement pump is directed through a pilot-operated pressure-compensated control valve to the hydraulic motor. The valve has a continuous bias to a fan-on position for directing fluid to the fan motor. Flow to the fan motor is diverted by the valve as a function of the pressure of the fluid in the system. In addition, flow to the fan motor is diverted as a function of a pilot pressure signal which is controlled by the temperature of the engine coolant fluid. The valve failsafes to a condition directing maximum flow to the fan motor in the event of loss of pilot fluid pressure.

대표청구항 ▼

Apparatus for driving a fan which directs air flow through a vehicle cooling system, said apparatus comprising a pump, a rotary hydraulic motor in fluid communication with said pump and having an output shaft drivingly connected with the fan, a pilot operated flow control valve in fluid communicatio

Apparatus for driving a fan which directs air flow through a vehicle cooling system, said apparatus comprising a pump, a rotary hydraulic motor in fluid communication with said pump and having an output shaft drivingly connected with the fan, a pilot operated flow control valve in fluid communication with said pump and said rotary hydraulic motor, conduit means for directing fluid from said pump through said pilot operated flow control valve to said rotary hydraulic motor, means for providing a pilot fluid pressure signal in response to the temperature of the vehicle cooling system, means for conducting said pilot fluid pressure signal to said pilot operated flow control valve, said pilot operated flow control valve being operable in response to said pilot fluid pressure signal to control fluid flow from said pump to said rotary hydraulic motor, and said pilot operated flow control valve including means for modulating flow to said rotary hydraulic motor in response to the pressure of fluid flowing therethrough and for restricting flow to said rotary hydraulic motor at a predetermined level of pressure of the fluid flowing through said pilot operated flow control valve.