Patent ID: 6286308
Filing Date: 2001-09-11
Classification: F01P

Abstract:
A drive system for a cooling fan that blows air to a cooling object, said drive system comprising:a primary hydraulic pump driven by an engine;an operating valve that supplies a discharged pressurized fluid of the primary hydraulic pump to an actuator;a first hydraulic rotary machine that rotates the cooling fan;a second hydraulic rotary machine that rotates the cooling fan;a return circuit that supplies a returning pressurized fluid from said operating valve to the first hydraulic rotary machine; anda hydraulic pressure source that is energized by the engine and that directly supplies pressurized fluid to the second hydraulic rotary machine;wherein a hydraulic motor is driven by the returning pressurized fluid of said return circuit, a variable displacement type hydraulic pump is mechanically connected to the hydraulic motor to form a pressure converter, and a discharged pressurized fluid of the variable displacement type hydraulic pump is supplied to the first hydraulic rotary machine.