Structural member having closed sections

摘要

A structural member having a closed section, and an apparatus and a method for producing the same are provided to decrease production costs and secure the dimensional accuracy by a simple construction. The apparatus produces a structural member provided with a channel-shaped sectional portion and closed sectional portions adjacent thereto by bending a work and includes a press mold formed of a punch and a die oppositely installed and used for press-forming so that both side edges of the work are caused to overlap on the bottom wall of the channel-shaped sectional portion, and a fall-down prevention means which prevents both side edges opposed to each other of the work to be press-formed in the press mold from falling down and guides both side edges so that the end faces thereof are brought into contact with each other. Since the die applies a compression force to the work due to the end faces of the work brought into contact with the fall-down prevention means being pressed to each other, a curved portion having a residual compression stress between the longitudinal outer side wall and the vertical outer side wall is formed. <IMAGE>