To dispense with a short pipe member when mounting a nut for bolt fastening on a hydroforming article, to prevent a difficulty in hydroforming for mounting a nut from increasing, to lengthen the length of a nut so as to secure a sufficient strength when fastening the bolt, and to be applicable for a thin-walled hydroforming article.
The method includes the step of: inserting a metal pipe into a split die having a piercing punch which is movable perpendicular or diagonally to a pipe axis and has the tip with a diameter smaller than that of an intermediate part, and the periphery of the tip of which is disposed with a nut having an inner diameter larger than the outer diameter of the tip and smaller than the outer diameter of the intermediate part; hydroforming; thereafter moving the piercing punch forward to punch a part of the hydroforming article; and burying the nut into the metal pipe while pushing the nut in the intermediate part arranged backward of the nut.
SATO KOICHI
KURIYAMA YUKIHISA
| JPH07139532A | 1995-05-30 | |||
| JP2003334625A | 2003-11-25 | |||
| JP2001300655A | 2001-10-30 | |||
| JP2001099125A | 2001-04-10 | |||
| JPS3534116Y1 | ||||
| JPS353814Y1 | ||||
| JPH06198358A | 1994-07-19 |
Tetsuo Kanamoto
Miaki Kametani