| 摘要 |
<P>PROBLEM TO BE SOLVED: To suppress twist in a negative direction and also to suppress occurrence of fold lines and crease marks generated in a vertical wall part outside a curvature, when bend-forming is applied on a channel member with a curved channel section using a two-stage bend-forming method. Ž<P>SOLUTION: The forming method employs the two-stage bend-forming method for applying a first forming to produce a preliminary formed body equipped with a curved channel section and then applies a second forming on the preliminary formed body. In the preliminary formed body, an angle θpa, which is determined by a preliminary horizontal wall part 11a and a preliminary vertical wall part 12a, is set to be larger than an angle θp, which is determined by a horizontal wall part and a vertical wall part of the channel member. Also, in relation to the θpa, a bending angle βc of a preliminary first bending point 14ao outside the curvature of the preliminary curved channel section 1ca is set to be smaller than a bending angle βs of a preliminary first bending point 14ao outside the curvature of the preliminary straight channel section 1sa. (βs-βc) is desirable to set at 10° or larger. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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