DEVICE FOR PREVENTING THE REVERSAL OF A HYDRAULIC ACTUATOR

摘要

A device for preventing the reversal of a hydraulic actuator comprising a hydraulic actuator for driving an inertia body, a main valve that can be changed over between a driving state in which pressure oil is supplied to one of first and second ports of the hydraulic actuator with the other of the two ports being caused to communicate with a tank and a neutral state in which the first and second ports are cut off, a safety valve for allowing pressure oil to flow from either of the first and second ports to the tank when the pressure of either of the first and second port sides exceeds a pre-set high pressure, a suction valve for sucking oil into either of the first and second ports when the pressure of either of the first and second port sides becomes negative, and a reversal prevention valve for causing the first and second port sides to communicate with the tank respectively when the pressures on the first and second port sides are higher than a certain pre-set pressure which is lower than the pre-set high pressure.