| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a manufacturing method for torsion beam, capable of reducing tensile residual stress at a lug section by only cold forming, without stress relief heat treatment. <P>SOLUTION: The torsion beam has such a product shape as to be straight in the longitudinal direction and that both ends in the width direction form a curl-shaped lug section 1c at a part thereof in the longitudinal direction and that a remaining width portion is of U-shaped cross-section shape of a single layer, by forming a metal plate blank (workpiece 1). First, a region to form the lug section of the blank is worked by curling and a portion in the width direction is then bent into a U-shaped cross-section. At the same time, a U-shaped bottom outer face side of the U-shaped cross section is bent to form the outside thereof by bending work in the longitudinal direction. Next, bending correction processing is implemented to straighten a portion in the longitudinal direction, thereby applying a residual plastic flexural strain of 0.2-0.6% to the lug. <P>COPYRIGHT: (C)2012,JPO&INPIT</p> |
