| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a method which can form a structure having a closed cross section from a flat plate material in a simple and highly accurate manner. <P>SOLUTION: A flat plate-shaped working material B is press-formed so that a bent portion B4 is formed at a position of a boundary between a bottom and a left wall B2 and between the bottom and a right wall B2 along the longitudinal direction thereof and, further, a portion corresponding to the sidewalls B2 is formed to a curved form. Thereafter, in such a state that a portion to be formed into the bottom is held from a direction of the plate thickness between a punch 3 and a pad 4, the punch 3 is forced into between a pair of dies 5 to form the bent portion B4 by bending at the boundary position in a direction that the left and right sidewalls B2 become close to each other. The sectional form at the portion into which the punch 3 has been forced is the sectional form or a form close to the sectional form of the bottom B1 after forming into the closed cross sectional structure and the boundary continued from the bottom B1. A pair of specific guide faces 6a are provided at the forcing-side position of the punch 3 in the pair of dies 5. <P>COPYRIGHT: (C)2011,JPO&INPIT</p> |
