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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 circ

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.

대표청구항 ▼

An automotive radiator cooling system comprising: a cooling fan operative to direct cooling air to an automotive radiator; a hydraulic circuit; a hydraulic pump disposed in said circuit and driven by an external power to circulate a pressurized hydraulic fluid through said circuit; a hydraulic motor

An automotive radiator cooling system comprising: a cooling fan operative to direct cooling air to an automotive radiator; a hydraulic circuit; a hydraulic pump disposed in said circuit and driven by an external power to circulate a pressurized hydraulic fluid through said circuit; a hydraulic motor drivingly connected to said cooling fan and disposed in said circuit so that said motor is hydraulically driven to rotate said cooling fan; a reservoir connected to said circuit downstream of said hydraulic motor to receive the hydraulic fluid flowing out of said hydraulic motor; a bypass line extending in bypassing relationship to said hydraulic motor and communicated at one end with a part of said circuit adjacent to an inlet of said hydraulic motor and at the other end with said reservoir; and a check valve means operative to permit a flow of the hydraulic fluid from said reservoir through said bypass line back into said part of said circuit only when the pressure in said part of said circuit is lowered beyond a predetermined level, thereby preventing the occurrence of cavitation when the hydraulic pump is stopped while the fan is rotating at high speed; wherein said hydraulic motor includes a housing, a shaft having an end drivingly connected to said cooling fan and rotatably mounted in said housing, and a shaft sealing means associated with said shaft to cooperate therewith and with said housing to define an oil chamber; and wherein said bypass line is formed in said housing of the hydraulic motor and includes said oil chamber.