| 摘要 |
PURPOSE:To enhance the energy saving effect lay reducing the rate of flow supplied to a servo valve not only in the high speed operation but also at the low speed operation. CONSTITUTION:A solenoid bypass valve 29 whose opening area varies in compliance with the car speed is installed in a bypass line 28 which bypasses to the low pressure side the working oil flowing through a flow path leading from the downstream of a measuring orifice 23 to a flow control valve 11, while a pressure sensitive bypass valve 33 whose opening area varies in compliance with the load pressure is installed parallel with the solenoid bypass valve, and that of the variable throttles of a bridge circuit constituting a servo valve 12 which lies on the pump side is adjusted by a semi-center open valve while the variable throttle on the reserver 17 side is adjusted by a center open valve. |
