| 摘要 |
PROBLEM TO BE SOLVED: To suppress the consumption of the waste energy of a pump so as to sufficiently save the energy when an actuator is not operated and the required operating hydraulic force is low. SOLUTION: A required flow of the hydraulic oil, which is led into a first pressure chamber 15, is led to a discharge passage 8 through a control orifice 9, and the excessive flow is bypassed to a drain passage 19 to be controlled by the movement of a spool valve 14. The control orifice 9 is formed of a main orifice 60 and a sub orifice 62. A cylindrical movable sleeve 37 provided with a through hole 40 and an opening 41, which can be respectively communicated with the drain passage 19 and the lead-in passage 20, is provided between a spool valve housing hole 5 and the spool valve 14, and one end 37a of the movable sleeve 37 is faced to the first pressure chamber 15, and the other end 37b thereof is faced to a low-pressure chamber 39. Furthermore, a spring member 38 for giving the deviating force to the first pressure chamber 15 is provided in the movable sleeve 37. |
