| 摘要 |
PROBLEM TO BE SOLVED: To facilitate the removal of scrap by surely returning the scrap punched out with a piercing punch back into the hole, in the piercing-working for piercing the hole on a pipe with the piercing punch when a hydraulic-pressure bulge-working is applied. SOLUTION: In the piercing-working for piercing the hole 13 on the pipe 1 by moving the piercing punch 11 forward and back in the sheet thickness shearing direction of the pipe 1 when the hydraulic-pressure bulge-working for forming the bulged part on the pipe 1 is applied by arranging the pipe 1 in dies 2, 3 and applying the inner pressure and the axial compressed load to the pipe 1, firstly, the top end surface 11a in the piercing punch 11 and the inner surface 2a of the die, are positioned at almost the same surface level. This working contains a first process in which the bulged part is formed on the pipe 1 with the hydraulic pressure bulge-working, a second process in which the hole 1a is semi-punched on the pipe 1 by advancing or retreating in the sheet thickness shearing direction of the pipe 1, and a third process in which the hole 13 is perfectly punched out on the pipe 1 by retreating or advancing the piercing punch 11 in the reverse direction to the second process. COPYRIGHT: (C)2005,JPO&NCIPI
|
