| 摘要 |
<p>PURPOSE:To enable supply of a large flow rate to an actuator with the simple structure by providing a directional control valve for connecting and intercepting a discharge passage and a load pressure introducing passage of a hydraulic pump and by interlocking this directional control valve with an operation valve so as to satisfy a predetermined state. CONSTITUTION:In a hydraulic circuit of a load pressure detecting type in which an actuator 3 is provided at a discharge passage of a hydraulic pump through an operation valve 2, a flow rate supplied to the operation valve 2 from the hydraulic pump 1 is controlled by a control valve 5 and this control valve 5 is pressed in the direction to increase the supply flow rate by a load pressure of a load pressure introducing passage 10, there is provided a directional control valve 21 for connecting and intercepting the discharge passage of the hydraulic pump 1 and the load pressure introducing passage 10. This directional control valve 21 is switched to a load pressure control release position G for connecting the discharge passage 20 to the control valve side 10A by a pilot pressure supplied by a pressure receiving part 23. And a pilot line 24 connected to the pressure receiving part 23 of the directional control valve 21 is connected to an outlet 26 of a shuttle valve 25, while a first and a second inlets 27 and 27 of this valve 25 is connected to a first and a second pilot pipings 14 and 15. respectively.</p> |
