| 摘要 |
The present invention relates to a die cushion system for a press apparatus capable of lifting a press die in a lower part to correspond to lifting of a press slide in an upper part of the press apparatus. The die cushion system for a press apparatus comprises: a hydraulic cylinder for supporting a press die; a proportional flow control valve for lifting the hydraulic cylinder by supplying a hydraulic fluid to a lower port of the hydraulic cylinder, or for allowing the hydraulic fluid inside the hydraulic cylinder to flow out by receiving the hydraulic fluid from the lower port when the hydraulic cylinder is lowered; a constant pressure supplying means to lower the hydraulic cylinder by supplying a pressure fluid to an upper port of the hydraulic cylinder; and a controller to control operation of the proportional flow control valve for lowering and lifting the press die according to a position of a press slide through a die cushion position detector and a slide position detector, and to control in order that the press die applies multiple stages of reaction forces with respect to the press slide while the press slide is lowered. The present invention has an effect of minimizing the occurrence of residual stress and elastic restoration due to plastic deformation of a press object by applying a forming pressure with various patterns by improving the response speed of the die cushion with respect to the press slide. |
