| 摘要 |
PROBLEM TO BE SOLVED: To provide a hydraulic control system with a low price and with capability to increase an operating speed of an actuator without increasing a revolution speed of an engine. SOLUTION: The system is characterized in that it includes a supplying passage 21 for connecting the actuator A and a main pump P1, a fixed delivery sub-pump P2 whose driving source is an engine E, an interfluent passage 41 for flowing discharge oil of the sub-pump P2 into the supplying passage 21, a metering valve 32 provided at a sucking side of the sub-pump P2, a directional control valve B that is provided in the supplying passage 21 located downstream for the interfluent position in the interfluent passage 41 and links the main pump P1 and the sub-pump P2 to a tank or the actuator A according to a direction selected position, and load sensing mechanisms 33, 36 for controlling a discharge pressure of the main pump according to a load of the actuator. The metering valve 32 keeps its throttling position when a link of the sub-pump and the actuator is cut off by the directional control valve B, while it keeps its opening position when the sub-pump and the actuator are linked together by the directional control valve. COPYRIGHT: (C)2004,JPO
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