METHOD FOR HYDRAULICALLY CONTROLLING AUXILIARY CYLINDER OF U PRESS

摘要

PURPOSE:To make it possible to reduce the equipment load on a U press and to assure the shape of the U can obtd. by said press by controlling hydraulically the main cylinder and auxiliary cylinder of the U press so as to maintain roughly the specified ratio between the forming force of the former and the pressing force of the latter at all times. CONSTITUTION:A U press forms a material to be formed to a U can by means of a punch driven to descend by a main cylinder 8 and a rocker arm 1 actuated by an auxiliary cylinder 6. Said cylinder 6 of the above-mentioned U press receives the supply of an oil pressure via a servocontrol valve 17 from a hydraulic pump 14 which supplies the oil pressure to the cylinder 8. The oil pressure on the cylinder 6 is controlled with the valve 17 so that the ratio of both oil pressures detected by the pressure detector 15 provided to the cylinder 8 and the pressure detector 16 provided to the cylinder 6 is maintained constant. The reduction in the equipment load and the assurance of the U can shape are thus made possible and further the expansion in the range of the wall thickness that can be formed with respect to the specified threshold of the equipment strength is made possible.