| 摘要 |
PROBLEM TO BE SOLVED: To manufacture parts having the bent part of a small shoulder radius at the tip of a bent part without generating cracks in a bent shoulder part even when using a steel sheet having high strength and small stretch as a workpiece. SOLUTION: After forming a preliminarily bent article having a bent part which has larger shoulder radius than the target shoulder radius by applying preliminary bending to the steel sheet, in the state where the outside of unworked parts on both sides of the preliminarily bent article is brought into contact with two fixed walls forming a predetermined angle, the unworked part on one side end of the preliminarily bent article is restrained and the other side end of the preliminarily bent article is pressed in the bending direction. COPYRIGHT: (C)2010,JPO&INPIT
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