| 摘要 |
PROBLEM TO BE SOLVED: To provide a hydraulic bulging method by which the expansion rate is remarkably increased without generating buckling. SOLUTION: A forcing means 20 in which two slide dies 14, 15 are relatively moved and stopper means 30 by which the slide dies 14, 15 are fixed to and unfixed from an open position are arranged around a forming die 10 in which two slide dies 14, 15 are slidably arranged on a slide base 13. First, in the state where the slide dies 14, 15 are fixed in the open position, the middle part of a pipe stock P is preliminarily bulged by forcing the pipe stock P in the axial direction while applying an internal pressure to the pipe stock P with die pushing cylinders 21. After that, the preliminarily bulged part is significantly bulged by pulling the rods 31a of stopping cylinders 31 out of the engaging holes 33 of the slide dies 14, 15 and relatively moving the two slide dies 14, 15 in the direction in which they approach each other with the die pushing cylinders 21. COPYRIGHT: (C)2006,JPO&NCIPI
|
