| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To avoid loss in driving a pump, and decrease an engine load. <P>SOLUTION: The hydraulic control system includes a plurality of pumps, and circuit systems to each of which an open-center-type transfer valve is connected. Out of the circuit systems, the downstream paths of a 1st group and a 2nd group B, C respectively are allowed to gather in a confluence path 41, in which an auxiliary transfer valve 16 is provided to supply pressure oil from the plurality of pumps to an actuator of the auxiliary transfer valve 16. In the hydraulic control system, an open control valve 42 is provided upstream of the confluence path 41 and in the downstream path of the 2nd-group circuit system C. In accordance with the pump discharge pressure of the 1st-group circuit system B and the pump discharge pressure of the 2nd-group circuit system C, the open control valve 42 opens the downstream path to a discharge flow path 10 communicating with a tank. <P>COPYRIGHT: (C)2006,JPO&NCIPI</p> |
