| 摘要 |
PROBLEM TO BE SOLVED: To provide a fluid-pressure circuit which can perform directly piloted operation of a main control valve and at the same time can correctly grasp interlocking operational condition without using a pressure sensor. SOLUTION: A plurality of movable valve bodies 54St1, 54Sw, 54St2, 54Bm1 of the main control valve 23 supply to a plurality of actuators by directionally controlling fluid discharged from pumps 67a, 67b. Valve arrangements 21a, 21b pilot-operate the plurality of movable valve bodies 54St1, 54Sw, 54St2, 54Bm1 by a pilot pressure in accordance with manipulated variable of an operation element of the valve arrangements 21a, 21b and at the same time output electrical signals in accordance with manipulated variable. A controller 25 outputs control signal in accordance with interlocking operational condition by judging interlocking operational condition by electric signals output from the valve arrangements 21a, 21b. Solenoid controlled proportional valves 116, 117, 118 output pilot controlled pressure in accordance with control signal from the controller 25 and then change the movable valve bodies 54St1, 54Sw, 54St2, 54Bm1 in accordance with interlocking operational condition. COPYRIGHT: (C)2009,JPO&INPIT
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