ARRANGEMENT FOR INFLUENCING THE OPERATING QUANTITY OF A SERVO-MOTOR

摘要

The invention relates to a fluid pressure supply and exhaust system for controlling a two port servo-motor wherein negative loads are anticipated for one side of the servo-motor The system has a switching valve unit for selecting parallel supply and exhaust branches to direct supply fluid to the servo-motor side subjected to negative loading. There are pressure regulating and throttling valves in the supply branch and a reducing valve in the exhaust branch. The supply pressure downstream from the throttle valve is directed to the reducing valve with a valve closing effect so that a sharp negative load will simultaneously reduce the supply pressure to the servo-motor while increasing the throttling of the return flow.