| 摘要 |
This control valve is provided with: a housing having a high-pressure passage which is in communication with a hydraulic pressure supply source, a low-pressure passage which is in communication with a tank for storing hydraulic fluid, a cylinder passage which is in communication with a hydraulic actuator, and a sleeve which is connected to the high-pressure passage, the low-pressure passage, and the cylinder passage; a lift lock poppet valve provided within the cylinder passage, the lift lock poppet valve being capable of taking an open position at which the lift lock poppet valve connects the sleeve and the hydraulic actuator, the lift lock poppet valve being also capable of taking a closed position at which the lift lock poppet valve blocks the communication between the sleeve and the hydraulic actuator, the lift lock poppet valve having a poppet valve body having a back-pressure chamber therein; a back-pressure passage for connecting the low-pressure passage and the back-pressure chamber of the poppet valve body and having a solenoid valve provided between the ends of the back-pressure passage; and an emergency operation valve having an emergency operation valve body provided movable forward and backward between a use position at which the emergency operation valve body presses the poppet valve body, and a retracted position at which the emergency operation valve body is separated from the poppet valve body, the emergency operation valve body being seated on a valve seat when located at the retracted position, thereby providing mechanical sealing. |
