To provide a method for mass-producing hollow pillar-shaped parts having a shape excellent in collision property.
The hollow pillar-shaped parts which include: a top wall part 11; a bottom wall part and a pair of vertical wall parts 13 which are connected with the top wall part 11 at both ends and on which a bulged part 15 having a shape bulging outward is formed in the connecting region to the top wall part 11 of the vertical wall part 13 are manufactured. The method of manufacturing it includes, at least, a stage where an intermediate formed body 30 before the bulged part 15 is formed is formed and a stage where the bulged part 15 is formed by clamping the intermediate formed body 30 with upper and lower dies 41, 42 and making a portion 32 equivalent to the connecting region 14 of the intermediate formed body 30 deform by buckling toward the outside.
DATE RYOSUKE
OKINO SHIGEKI
HIROZAWA SHUGO
Kunihiko Shiromura
Tsuyoshi Kumano
Yusuke Noguchi