| 摘要 |
The present invention was made with the object of eliminating the short pipe member when attaching a bolting nut to a hydroformed part, preventing an increase in the difficulty of hydroforming for attaching the nut, extending the nut length so as to enable sufficient strength at the time of bolting, and enabling application even to thin wall hydroformed parts and comprises inserting a metal pipe into a split mold having a pierce punch able to be moved perpendicular to an axis of the inserted metal pipe or in a slanted direction, having a front part narrower than a center part, and having around the front part a nut having an inside diameter larger than an outside diameter of the front part and smaller than an outside diameter of the center part; hydroforming it; then making the pierce punch advance to pierce part of the hydroformed part and pushing the nut by a center part arranged behind the nut and embedding the nut in the metal pipe. |
