| 摘要 |
PURPOSE:To reduce energy consumption, by using a valve, which operates by a pressure in the downstream side of an orifice provided in the delivery side of a pump, and returning the whole amount of fluid delivered from the pump to its suction side when an oil hydraulic actuator is inoperative. CONSTITUTION:A variable orifice 4 is formed between the delivery side of a pump 1 and a supply pressure oil pipe 2b to an oil hydraulic actuator 12. When the oil hydraulic actuator is inoperative, a selector valve 40 connects a pipe line 30 with a drain 6 by resilient force of a spring 49 because a low pressure is generated in the downstream side of the orifice 4. If the pipe line 30 generates a low pressure, a piston 22, driving the variable orifice positioned in a flowcontrol valve 20, is moved leftward by the delivery pressure of the pump, and the delivery side of the pump communicates with its suction side in the flow control valve 20. |
