PURPOSE: To prevent excessive rise in hydraulic operating oil temperature by constituting in such a way that a part of hydraulic operating oil in a hydraulically closed circuit can be discharged outside by means of a clutch valve.
CONSTITUTION: A clutch valve 69 is set so as to be switched into three positions, such as a clutch-on position to intercept the suction side from the discharge side of a hydraulic pump, a clutch-off position to communicate the suction side with the discharge side of the hydraulic pump and a communication/ discharge position to communicate the suction side with the discharge side of the hydraulic pump and also to open outside. A part of hydraulic operating oil in a hydraulically closed circuit can be discharged outside by means of this clutch valve 69.
HAYASHI TSUTOMU
SAITO MITSURU
| JPH01210656A | 1989-08-24 | |||
| JPS63140163A | 1988-06-11 | |||
| JPS63203960A | 1988-08-23 |