Patent ID: 8814235

Claim:
A bumper device for a vehicle, comprising: a bumper reinforcement that extends in a direction of the width of a vehicle, the bumper reinforcement having two opposite ends; a pair of side members that extend in a front-rear direction of the vehicle; and a pair of crush boxes each located at one of the ends of the bumper reinforcement, wherein each crush box is located between the bumper reinforcement and the corresponding side member, and each crush box is a shock absorber and includes: a cylindrical small diameter portion; a cylindrical large diameter portion having a protrusion, wherein an attachment portion is integrally formed with the large diameter portion and extends radially outward and is fixed to the corresponding side member, the protrusion is integrally formed with the large diameter portion and continuously extends to the attachment portion in the axial direction and protrudes radially outward, and the attachment portion is arranged at an angular position that the protrusion extends; and an annular step portion that connects the small diameter portion and the large diameter portion to each other, wherein the shock absorber absorbs load applied thereto through plastic deformation in which the small diameter portion is folded back into the large diameter portion and at the annular step portion as the starting point of the deformation, so that impact energy is absorbed.