| 摘要 |
PURPOSE:To prevent the occurrence of a surge to an actuator and a pressure shock and also to make a pressure control valve small-sized. CONSTITUTION:A pressure chamber 5 connected to a high pressure side circuit 1 through a throttle 6 is formed at the rear of a main valve 4, and a differential pressure operating-type booster piston 11 is enclosed in it, the first pressure chambers 12, 12' with a small pressure area at one side are connected to the pressure chamber 5, the second pressure chamber 13 with a large pressure area at the other side is connected to the pressure chamber 5 through a damping throttle 18. A pilot valve 19 is brought into contact with the valve seat section 30 of the booster piston 11, and the pressing force of a spring 24 of the pilot valve 19 is increased as the booster piston 11 is moved. The pressure of the pressure chamber 5 is gradually increased as the booster piston 11 is moved after the fluid pressure of the high pressure side circuit 1 exceeds a predetermined pressure and till it reaches a preset pressure, thus the pressure of the high pressure side circuit 1 can be gradually increased. |
