METHOD FOR MANUFACTURING CURVED COMPONENT HAVING POLYGONAL CLOSED-CROSS-SECTIONAL STRUCTURE AND CURVED COMPONENT HAVING POLYGONAL CLOSED-CROSS-SECTIONAL STRUCTURE AND MANUFACTURED USING SAID METHOD

摘要

[Task] It is to provide a technique for press-forming a polygonal closed cross-section structural component with a curved form from a metal sheet. [Solution for task] In the production of a polygonal closed cross-section structural component with a curved form along its longitudinal direction having flange portions extended along a ridge line located at an innermost side of the curved form in a radial direction, the present invention is characterized in that a gutter-shaped pre-processed part is first press-formed to have plural ridge lines corresponding to the corner portions of the polygonal closed cross-section of the component in a cross-sectional form developed by cutting the component at a position corresponding to the ridge line located at the innermost side in the radial direction to provide a flange portion extending along the ridge line at the resulting respective ends wherein each of the ridge lines corresponding to the corner portions has a radius of curvature equal to or smaller than a radius of curvature of the corresponding ridge line of the component; and the pre-processed part is then press-formed so as to deform inward in the cross-sectional direction at a position of one or more of the plural ridge lines to butt the ridge lines located at the innermost sides and the flange portions to each other.