A bumper beam is roll formed so that it gets a closed cross section with, along the length, constant cross section having at least two closed chambers (15, 16) separated by an essentially horizontal partition wall (14). Each chamber has a side (19), which is turned away from the vehicle, with at least one longitudinal concave portion (20, 21; 22, 23) extending along the entire length and one side (24), which is facing the vehicle, with at least one longitudinal convex portion (25, 26; 27, 28) extending along the entire length. After the roll forming, some portions (32) of the cross section are pressed together vertically or horizontally in order to adapt the deformation properties.

A bumper beam is roll formed so that it gets a closed cross section with, along the length, constant cross section having at least two closed chambers (15, 16) separated by an essentially horizontal partition wall (14). Each chamber has a side (19), which is turned away from the vehicle, with at least one longitudinal concave portion (20, 21; 22, 23) extending along the entire length and one side (24), which is facing the vehicle, with at least one longitudinal convex portion (25, 26; 27, 28) extending along the entire length. After the roll forming, some portions (32) of the cross section are pressed together vertically or horizontally in order to adapt the deformation properties.

A vehicle reinforcement beam is roll formed from a metal sheet to provide a multi-tubular reinforcement beam that includes two adjacent tubular sections that share a common center wall. The outer sections the metal sheet extend from opposing ends of the common center wall and are formed to enclose the adjacent tubular sections. An edge portion of the metal sheet that is bent to have a bend radius of about 3-9 mm, where the edge portions attach in abutting and continuous contact with the common center wall to form crevices between the adjacent tubular sections along the first and second faces. A weld is formed in each of the crevices to define crevice ribs in general alignment with and at each of the opposing first and second ends of the common center wall that are configured to improve bending strength and torsional strength of the reinforcement beam.

The present disclosure relates to bumper beams having a closed cross-section, the closed cross-section being formed by one or more metal plates. The metal plates include a plurality of holes and a plurality of projections, wherein the projections engage with corresponding holes to retain the closed cross-section. The present disclosure further relates to rocker panels having a closed cross-section, the closed cross-section being formed by one or more metal plates, and the metal plates including a plurality of holes and a plurality of projections, wherein the projections engage with corresponding holes to retain the closed cross-section. The present disclosure further relates to methods of manufacturing such bumper reinforcing members and rocker panels.

A method and apparatus manufactures a closed structure part without flange having a curvature and welded edges along a longitudinal direction of the part and further having a varying cross-sectional shape, from two metal plates. Each of two metal plates provided with a curvature along the longitudinal direction of the plate and provided with both ends in a width direction of the plate, are press-formed such that a folding line is formed at positions corresponding to a non-welded bent edge in a cross section of the part, and stacked on each other vertically such that their bulging sides face outward. Their left ends and right ends in the width direction are mutually welded along the longitudinal direction to form welded edges.

A reinforcement beam is roll formed from a metal sheet for use in a vehicle bumper system. The reinforcement beam includes adjacent tubes having a common center wall and lateral portions extending from opposing sides of the common center wall that are roll formed simultaneously in the same rotational direction to enclose interior volumes of the adjacent tubes and to define top and bottom walls and front and rear wall of the reinforcement beam. The front walls of the adjacent tubes each include a channel rib depressed into the interior volume of the respective adjacent tube longitudinally along the reinforcement beam for stiffening the respective front wall. A weld is formed separately in each of the seams between the front walls and between the rear walls, thereby defining a crevice rib between the channel ribs to improve the bending strength and torsional strength of the reinforcement beam.

A multi-tubular beam for a vehicle, such as a vehicle structure or a bumper reinforcement, includes an elongated beam formed with a metal sheet. The metal sheet has a central section and outer sections extending along a length of the metal sheet. The outer sections are disposed in opposing directions from the outer edges of the central section to provide adjacent first and second tubular portions. The central section forms a common center wall between the adjacent first and second tubular portions. A first edge portion of the metal sheet is disposed along and in parallel alignment with the center wall. The first edge portion is attached to the center wall at a first weld joint to form the first tubular portion. The first weld joint includes a weld material that extends through a thickness of the center wall and into a thickness of the first edge portion.

A method for manufacturing a rollforming frame includes: forming a first vertical wall and a first horizontal wall connected to each other at two opposite ends of a to-be-machined plate; rolling and bending the first horizontal wall to form a stepped bent structure; rolling and bending the first horizontal wall to form a second vertical wall, a second horizontal wall, and a third horizontal wall; rolling and bending the second horizontal wall to form a third vertical wall and a fourth horizontal wall; rolling and bending the third horizontal wall to form a fourth vertical wall and a fifth horizontal wall; rolling and bending one end of the fifth horizontal wall away from the fourth vertical wall to form a connecting edge and a sixth horizontal wall; rolling and bending the sixth horizontal wall to form a fifth vertical wall and a seventh horizontal wall.