| 摘要 |
PROBLEM TO BE SOLVED: To cushion an impact generated in moving a load down from a load held state. SOLUTION: A fluid pressure controller is equipped with a load holding mechanism 20 for coupling, when the control valve is at a shutoff position c, a load-side pressure chamber 2a on which load pressure caused by load 1 acts and a control valve 6 to each other. The load holding mechanism 20 is equipped with an operation check valve 21 which controls the flow of a working fluid from the load-side pressure chamber 2a to the control valve 6 in response to pressure of a backing pressure chamber 25 and a meter out control valve 22 which controls the flow of a working fluid at a meter-out side when moving the load 1 down. The meter out control valve 22 is equipped with an opening area restraining means for restraining an increasing rate of an opening area to a moving amount of a spool 56 in an period of communication of a bypass passage 30 and a main passage 7b. When the control valve 6 switches from the shutoff position x to a load moving down position b, the bypass passage 30 and the main passage 7b are allowed to communicate with each other before the control valve 6 opens, thus restraining pressure of the main passage 7b from being increased by the opening area restraining means. COPYRIGHT: (C)2009,JPO&INPIT
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