| 摘要 |
PURPOSE:To save energy to be consumed by reducing setting pressures during the acceleration period of inertial mass by providing a means to change the setting pressures of a back-pressure valve through which oil for preventing negative pressures is supplied to an actuator by the pump pressure. CONSTITUTION:A hydraulic pump 1 to be driven by a prime mover 3 supplys hydraulic oil to an hydraulic motor 1 for inertial mass drive of a slewing motor, etc., through a direction switch valve 4. A supply pipeline 20 is also connected through check valves 18 and 19 to the pipeline between the switch valve 4 and the motor 1 and a tank 23, by which the occurrence of negative pressures in the motor 1 is prevented. A back-pressure valve 24 is also provided to the pipeline 20. A relief valve 10 for setting max. pressure is provided between the main pipeline 5 between the pump 1 and the valve 4 and the pipeline 20. The setting pressures of the back-pressure valve 24 can thus be changed by the pressures of the pump 1. |
