PURPOSE: To provide a method for bending a hollow member where the mass production is possible, and the wrinkle depth is obtained so that the shape of the hollow member is hardly damaged even when the wrinkle is generated by preliminarily forming grooves orthogonal to the longitudinal direction on the inner side of a wall to be bent forming the hollow part of a shape at the prescribed pitch, and executing the bending operation thereafter.
CONSTITUTION: Grooves 4 orthogonal to the longitudinal direction are preliminarily formed at the prescribed pitch on the inner side of a bent wall 3 forming the hollow space 2 of a hollow aluminum shape 1 is formed at the prescribed pitch, and the bending is executed thereafter. This constitution allows the bending deformation to be distributed to each groove 4 without being concentrated in one place, and the wrinkles generated by the bending become uniform, and the depth becomes small, and the bending can be achieved with hardly damaging the shape of the hollow shape. The grooves 4 can be provided in a relatively simple manner with a press or the like, and the mass production can also be facilitated. When the curvature of the bending is small, the bending can be achieved without using a core, and the working time is reduced thereby.
YASUNAGA SHIGENOBU
FUJIWARA AKIFUMI
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