Kobe Steel, Ltd.

Kabushiki Kaisha Kobe Seiko Sho

Satoshi Nimura

Toru Hashimura

Narikazu Hashimoto

Yoshihaya Imamura

Masatoshi Yoshida

Hiroyuki Yamashita

Kazumori Horiguchi

Hideki Ishitobi

Tsunetake Tsuyoshi

Koji Kariatsumari

A target tubular member with flange, such as a bumper stay, has a flange having an outer diameter larger than the diameter of an axial section and is formed by electromagnetic forming without excessive expansion. The tubular member with flange includes an axial member made of a tubular aluminum alloy extrudate and a flange member joined to an end of the axial member. The axial member has an end flange being integrated at its end and having an area smaller than that of the flange member. The flange member has a hole, and a cylindrical hole flange at the edge of the hole. The axial member fits in the hole of the flange member, the end flange is in intimate contact with the flange member, and the outer periphery of a small-diameter portion of the axial member is in intimate contact with the inner periphery of the hole flange. The hole flange is held between the end flange and a protrusion. The tubular member with flange may be produced by inserting an untreated pipe into the hole of the flange member and expanding the untreated pipe by electromagnetic forming.

Axial member with flange, connection member and production methods thereof

The bumper stay includes a cylindrical shaft member fit in to a hole of a bumper reinforce, a cylindrical reinforcing member fit in to the outer periphery of the shaft member in the rear side of the bumper reinforce, and a mounting flange member fit in to the outer periphery of the shaft member in its rear end. The shaft member is enlarged by electromagnetic forming and is tightly adhered to the inner peripheral surface of the hole formed in the bumper reinforce, the inner peripheral surface of the reinforcing member, and the inner peripheral surface of the hole flange formed in the mounting flange member, thereby these are joined with each other. Thin aluminum alloy extruded material can be used for the shaft member. With such configuration, when a bumper stay is fit in to the holes formed in the front and rear walls of the bumper reinforce and the bumper stay is enlarged by electromagnetic forming to join with the bumper reinforce, joining of the both can be firmly performed and sufficient strength and energy absorption quantity can be secured.

Bumper structure

A lightweight car body energy absorber made of Al alloy which provides a high energy absorption performance. The car body energy absorber comprises a hollow shape with a rectangular sectional profile and a reinforcing shape attached to the front face of the collision plane of the hollow shape, where the hollow shape and the reinforcing shape are aluminum alloy extruded shapes. The reinforcing shape has a hat-shaped open sectional profile, which is composed of a collision wall almost parallel to the collision plane of the hollow shape, plural mutually parallel horizontal ribs which support the collision wall, and vertical flanges provided at the tips of these ribs. The reinforcing shape is joined to the collision plane of the hollow shape through the vertical flanges.

Car body energy absorber and bumper stay

Growing community of inventors

Shimonoseki, Japan

Satoshi Nimura