LINE RELIEF VALVE

摘要

PROBLEM TO BE SOLVED: To easily variably set a relief pressure of a line relief valve. SOLUTION: A main poppet 101 is provided openably and closably between an actuator side passage 48 communicating with a hydraulic actuator and a return passage 50 communicating with a tank 49. Pilot pressure introduced into a spring chamber 105 opposite side to the actuator side passage 48 of the main poppet 101 is controlled by a pilot poppet 77. A spring 92 is provided to energize the pilot poppet 77 to the trapping direction of the pilot pressure. A relief pressure adjusting cylinder 52 controlling the energizing force of the spring 92 by the setting change pressure, and the setting change pressure is supplied to the relief pressure adjusting cylinder 52 from an electromagnetic proportional valve according to quantity of electricity. COPYRIGHT: (C)2003,JPO