| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To inexpensively and effectively prevent the hunting of an actuator regardless of a size and the like of the actuator. <P>SOLUTION: This pressure control valve 10 comprises a spool 24 for opening and closing a relief oil passage 59 branched from a discharge oil passage 50 of a hydraulic pump P, a spring 25 for energizing the spool 24 to a closing side of the relief oil passage 59, a pilot oil passage 59c for guiding a discharged pressure of the hydraulic pump P, a pilot oil chamber 42 connected with the pilot oil passage 59c for allowing the discharged pressure of the hydraulic pump P to act at an opening side of the spool 24, a load pressure introducing passage 60 for guiding the load pressure of the actuator (derricking cylinder 91 and extensible cylinder 92), a load pressure oil chamber 26 connected with the load pressure introducing passage 60 for allowing the load pressure of the actuator to act at a closing side of the spool 24, and a load pressure oil chamber volume adjusting means (piston 31 and piston moving knob 32) capable of adjusting a volume of the load pressure oil chamber 26. <P>COPYRIGHT: (C)2005,JPO&NCIPI</p> |
