Patent ID: 7896408

Claim:
A bumper structure to be mounted to a vehicle, comprising: a bumper reinforce formed of metal material with a hollow cross section elongated in a direction transverse to the vehicle longitudinal direction, said bumper reinforce having a front wall, a rear wall and a plurality of lateral walls connecting said front wall and said rear wall to provide said hollow cross section, further comprising holes penetrating said front wall and said rear wall in at least one portion of said bumper reinforce in the direction of elongation of the bumper reinforce; and cylindrical bumper stays fixed to said bumper reinforce, said bumper stays comprising cylindrical shaft members of aluminum alloy and having cylinder axes extending in the vehicle elongation direction, said bumper stays being fit in said holes of said bumper reinforce, and cylindrical reinforcing members fit to the outer periphery of said shaft members at the vehicle body side of said bumper reinforce, said shaft members being enlarged by electromagnetic forming and adheringly fixed to the inner peripheral surface of said holes of said front wall and said rear wall of said bumper reinforce and the inner peripheral surface of said cylindrical reinforcing members.