Kenyon & Kenyon
Automotive radiator cooling system
 An automotive radiator cooling system has a radiator cooling fan driven by a hydraulic motor actuated by a pressurized fluid fed through a hydraulic circuit from an engine-driven hydraulic pump. A bypass line extends in bypassing relationship to the hydraulic motor and has ends connected to the circuit upstream and downstream of the hydraulic motor, respectively. A check valve is provided in the bypass line and is operative to allow a flow of the fluid from a reservoir through the bypass line back into a part of the circuit upstream of the motor only when a pressure drop takes place in that part of the circuit due to free rotation of the cooling fan, and thus of the motor, independently of the drive by the hydraulic pump. The backward flow of the fluid is operative to compensate for the pressure drop to prevent the occurrence of cavitation in the circuit upstream of the motor. Desirably, the bypass line is incorporated into the housing of the hydraulic motor. 
Toyota Jidosha Kabushiki Kaisha Nippondenso Co., Ltd.
F F F B F F F F F
F16H F04D F16H B60K F04D F16H F01P F04C F16H
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Yasuo Tadashi Fumihiro Toshihiro Atusi Toshiki Yasushi
Takahara Setoguchi Takeuchi Ohshima Masui Sugiyama Suzuki