| 摘要 |
PROBLEM TO BE SOLVED: To provide a hydraulic drive system capable of passing working oil between a closed circuit and a tank in order to reduce temperature in the closed circuit when a hydraulic actuator is in operation and at a standstill. SOLUTION: The hydraulic drive system comprises the closed circuit C connecting the hydraulic actuator M to a hydraulic pump 10 via a pair of passages A and B, a charge pump 3 supplying working oil to the closed circuit C, a discharging oil valve 2 returning the working oil from the closed circuit C to the tank 1 when the discharging oil valve 2 is an open state caused by differential pressure across the pair of passages A and B generated by the action of the hydraulic actuator M, and a discharging oil passage 4 which is in a connecting state between the closed circuit C and the tank 1 when the hydraulic actuator M is at a standstill and flows the working oil from the closed circuit C to the tank 1 by the charge pump 3. COPYRIGHT: (C)2006,JPO&NCIPI
|
