| 摘要 |
PROBLEM TO BE SOLVED: To provide a fluid pressure control device which can suitably perform control on meter-out control valve even if a relief valve is opened when a load is descended. SOLUTION: The fluid pressure control device is equipped with a load securing mechanism 20 connecting a load side pressure chamber 2a of cylinder 2 and a control valve 6. The load securing mechanism 20 is equipped with: an operation check valve 21 permitting a stream of working fluid from the load side pressure chamber 2a to the control valve 6 based on a pressure of a back pressure chamber 25; a meter-out side control valve 22 controlling a stream of meter-out side when a load 1 is descended; and a relief valve 41 releasing the working fluid of the load side pressure chamber 2a when a pressure of the load side pressure chamber 2a reaches a predetermined pressure. The meter-out control valve 22 is equipped with a piston 59 moving a spool 56 by pilot pressure within a pilot chamber 23, and the piston 59 is equipped with a first piston 50 and second piston 51. The working fluid passing through the relief valve 41 is led between the first piston 50 and second piston 51. COPYRIGHT: (C)2010,JPO&INPIT
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