Crush box

Abstract

A crush box, which has a tubular body having a plurality of flat plate-shape sidewalls and having a polygonal shape in section, which is disposed in such an attitude that an axial direction of the tubular body matches a longitudinal direction of a vehicle, and which, when subjected to a compressive load in the axial direction, is crushed like an accordion in the axial direction to absorb impact energy, the crush box being configured such that a plurality of flanges projecting outward from the tubular body are provided along only a plurality of outer ridges located on an outer side in a lateral direction of the vehicle out of a plurality of ridges located along a boundary between the plurality of sidewalls, such that the plurality of flanges extend along an entire axial length of the tubular body, the tubular body is formed by a pair of body halves divided by a pair of upper and lower outer ridges located at upper and lower positions on the outer side in the lateral direction of the vehicle out of the plurality of ridges located along the boundary between the plurality of sidewalls, each of the pair of body halves has joint portions at its both ends located along the pair of upper and lower outer ridges, the joint portions are placed on each other and bonded together and project outward from the tubular body, and a pair of upper and lower flanges functioning as the plurality of flanges are formed by the joint portions, and the upper flange is provided so that the upper flange projects obliquely upward and outward in the lateral direction of the vehicle in section perpendicular to the axial direction of the tubular body, and the lower flange is provided so that the lower flange projects obliquely downward and outward in the lateral direction of the vehicle in section perpendicular to the axial direction of the tubular body.