| 摘要 |
PROBLEM TO BE SOLVED: To provide a hydraulic control device for reducing a leakage quantity from a pilot controlled directional valve while maintaining relation between an operation characteristic of the pilot controlled directional valve and an operation characteristic of a control valve. SOLUTION: This device has a pilot check valve 7 arranged between a load side pressure chamber 3a and the control valve 2, the spool type pilot controlled directional valve 19 arranged between a back pressure chamber 14 of the pilot check valve, the load side pressure chamber and the control valve and a pilot valve 4 for supplying pilot pressure to pilot chambers 2a 2b of the control valve 2 and a pilot chamber 19a of the pilot controlled directional valve, and associates the operation characteristic of the pilot controlled directional valve to the operation characteristic of the control valve. A seat part 29 is arranged on the outer periphery of a spool 41 for constituting the pilot controlled directional valve 19. When the pilot controlled directional valve exists in a cutoff position (x), clearance of the outer periphery of the spool 41 is blocked up by the seat part 29. COPYRIGHT: (C)2004,JPO
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