| 摘要 |
PURPOSE:To prevent a locking by the pressure difference between the input port and the exhaust port when a spool valve is closed, in a servovalve which consists of an electric actuator and a spool valve. CONSTITUTION:Between the exhaust port 10 of a spool valve 21, and a hydraulic pressure feeding source P and a reservoir 11, a change-over valve 15 which communicates between the exhaust port 10 and the hydraulic pressure feeding source P in the nonoperating time of an electric actuator 22 is provided, and between the output port 9 of the spool valve 21 and a hydraulic actuator B, a cut valve 5 which is closed in the nonoperating time of the electric actuator 22 is provided, and in the condition closing the spool valve 21, the hydraulic pressure of the hydraulic pressure feeding source P is fed to fill the inside of the spool valve 21 while cutting off the hydraulic pressure transmission to the hydraulic actuator B. Consequently, the responsiveness of the hydraulic actuator B is improved. |
