| 摘要 |
PROBLEM TO BE SOLVED: To make a structure having a closed section formable from a flat plate material easily and with fine dimensional accuracy.SOLUTION: In a first step of press forming, a worked material 1 is formed into a curvature shape which is required for the final closed section shape in a longitudinal direction and a width direction. In a next second step, the worked material formed in the first step is bending-formed in a direction in which right and left sidewall parts approach each other, by holding bottom parts 2, 3 between a punch 15 and a pad 16 from a board thickness direction. Next, in a third step, a die cavity having the same space shape as the final closed section shape is demarcated by butting a pair of flange parts 7, 8 mutually in a state where the bottom part of the worked material formed in the second step is arranged on the pad, and with a supporting faces supporting the bottom part of the pad and a forcing face into which right and left sidewall parts of a pair of pressurizing cams are forced. The pair of flange parts are pressed down to the sides of the cavity by the pressing-down part 31 of a second punch arranged above the pair of flange parts. |
