| 摘要 |
PURPOSE:To improve work efficiency and operability by providing a pilot control circuit with a pilot controlled directional control valve which is switched by the secondary pressure of a remote-controlled valve and adapted to selectively connect a flow control portion of a variable pump to a tank or a select valve. CONSTITUTION:A pilot control circuit is provided with a select valve 16 for selectively connecting an intermediate circuit to a hydraulic pump 13 or a tank 9 and a pilot controlled directional control valve 20 for selectively connecting a flow control portion 1a of a variable pump 1 to the tank 9 or the select valve 16. A pilot portion of the pilot controlled directional control valve 20 is connected to secondary side circuits 10a, 10b, 11a, 11b of remote-controlled valves 10, 11 through shuttle valves 21, 22, 23. In this arrangement, just a little operation for one of the remote-controlled valves 10, 11 will increase the discharge flow of the variable pump 1 to the maximum, so that work efficiency can be improved. The respective actuators can be controlled independently to improve the operability.
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