| 摘要 |
<p>PURPOSE:To reduce the generation of noises during pressing and to improve the working efficiency of a hydraulic press in the stage of working metallic plates with said press by monitoring and detecting the operating state of stroke parts and controlling the stroke speed. CONSTITUTION:In the stage of subjecting a metallic plate to pressing such as punching by means of the punch 3 at the preceding end of a piston rod 2 of a hydraulic press and a die 4, the position of the punch 3 is detected with a length measuring device 8 provided to a rolling wheel 8a abutting on the rod 2. The pulse signal A of the detected value is inputted to a position operating part 10 and is made to correspond to the time pulse signal B from a standard clock 14 in a speed operating part 13, by which the current position of the rod 2 is detected from A/B or B/A. At every stroke of the punch 3, the current position and the moving speed are compared with an intended position and an intended speed, and in a valve control part 65, the speed near the bottom dead point of the punch 3 is controlled with a supplying and discharging circuit 6 for pressure oil just before the punch abuts on the metallic plate, whereby the generation of the noise during pressing is reduced and working efficiency is improved.</p> |
