| 摘要 |
PROBLEM TO BE SOLVED: To provide a negative control circuit for an industrial machine capable of reducing energy loss extremely and supplying a required flow rate to a required work machine. SOLUTION: A priority valve 3 is connected with a fixed discharge pump 1, and a steering system circuit 6 and a work machine system circuit 8 are connected with the priority valve 3. Selector valves 14, 16, 17 connected with the work machine system circuit 8 are provided with pilot flow passages 22 to 24 separately from center open passages 18 to 20 to change pilot pressure acting in a pilot chamber 31 of a control valve V in accordance with opening area of the flow passages. The negative control valve V keeps a fully opened position c and a drain position a or an intermediate position b by action of pilot pressure. COPYRIGHT: (C)2006,JPO&NCIPI
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