| 摘要 |
The present invention relates to a hydraulic cylinder control valve, wherein the operations of a cylinder used for lifting and lowering are carried out by current control and, particularly, the current state of the cylinder can be maintained in an emergency case such as the engine stopping and the cutoff of power supply during operation. The hydraulic cylinder control valve comprises: a valve body forming the outer appearance and having a pump port connected to a hydraulic pump, a cylinder port connected to a hydraulic cylinder and a tank port connected to a hydraulic oil tank for storing discharged hydraulic oil; a main spool provided to the valve body and controlling the hydraulic oil supplied through the cylinder port so as to lift or lower the hydraulic cylinder; an opened proportional opening and closing valve driven by the current supply from the outside and moving the main spool by the pressure of the hydraulic oil supplied from the hydraulic pump such that the hydraulic pump and the cylinder can communicate with each other; a closed proportional control valve driven by the current supply from the outside and moving the main spool by the pressure of the hydraulic oil supplied from the hydraulic pump such that the hydraulic pump and the cylinder can be blocked from each other; and a locking control valve arranged between the main spool and the cylinder and driven by the current so as to allow only the flow of the hydraulic oil from the main spool to the cylinder in an off-state and make the main spool and the cylinder communicate with each other in an on-state. |
