| 摘要 |
PURPOSE:To obtain hydraulically-driven circuit without any energy loss and with excellent responsiveness by providing electrical pressure converters in a pump side port of an operating valve with pressure compensation and at a throttle circuit outlet. CONSTITUTION:When hydraulic oil flows to a single load 7a through driving a hydraulic motor 2, a differential pressure DELTAPc comes out between both sides of a variable throttle valve in a selector valve 6a. When the spring pressure of a flow control valve 5a is made equal to DELTAPc, the flow control valve 5a is opened or closed so as to maintain DELTAPc always constant even if load pressure P1C is changed, the flow being maintained constant. When the discharge pressure of the hydraulic pump 2 is controlled so that the differential pressure DELTAPv between an inlet side and an outlet side of the flow control valve 5a can maintain the minimum difference in pressure which can correspond to a change of load, pressure loss is not changed according to magnitude of load 7a but decreased. In a word, it is enough it the discharge pressure of a hydraulic pump 2 is controlled so as to keep the sum of DELTAPv and DELTAPc constant. |
