SLIDE EQUILIBRIUM DEVICE OF HYDRAULIC PRESS

PURPOSE:To raise (retract) a slide at a thigh speed and to perform rapid rising leveling control by supplying a working fluid to each control cylinder using a flow rate control valve and a servo valve. CONSTITUTION:A flow rate zero command is issued to a flow rate control valve 18 by a slide rising command and a full open command is outputted to each servo valve 19 so as to bring the opening degree of said valve 19 to a full-open state. The supply of a working fluid to a control cylinder 8 is stopped and the movement of a slide 4 is temporarily stopped. The flow rate of the working fluid corresponding to a preliminary inputted rising speed is calculated to set the flow rate of a flow rate control valve 18. At the same time, the stroke of each control cylinder 8 is detected by a position detection means 21. The opening degree of the servo valve 19 is controlled from these detected values. The working fluid is supplied to each control cylinder 8 by the flow rate command to the flow rate control valve 18 and the opening degree command to each servo valve 19, and the slide 4 rises at a set speed while keeping equilibrium. The above-mentioned operation is performed up to the predetermined rising position of the slide to perform the rising leveling control of the slide 4.