| 摘要 |
PURPOSE:To prevent the leak of the oil pressure from a load-side port during a working machine is in stop by installing a pilot check valve mechanism opened by a control pressure, between a spring chamber and a balance pressure chamber. CONSTITUTION:Since a control pressure Pc is not supplied when load application is suspended, a main poppet 2, pilot poppet 4, and a pilot check valve 6 are in closed state. Therefore, the pilot check valve 6 installed into a passage 1e which allows a spring chamber 1d to communicate with a pressure chamber 1c suppresses an oil pressure which flows into the pressure chamber 1c from the spring chamber 1d. Therefore, the oil leak from the pressure chamber 1c to the pilot pressure chamber 1b is prevented, and the natural lowering of the load on a working machine, etc. is prevented. |
