SELF-PIERCING ELEMENT, METHOD OF ATTACHMENT AND DIE MEMBER

摘要

A self-piercing element including a shank, a radial flange and a tubular barrel. The flange includes spaced concave surfaces and the annular bearing surface has an area at least four times the concave surfaces. The element is installed in a panel supported on a female die including a central die post, wherein the outer side wall is a frustoconical having an included angle between five and twelve degrees. During installation, the tubular barrel pierces an opening in the panel and the panel is drawn against the outer surface of the tubular barrel and the barrel is deformed into a U-shape. The flange is simultaneously received in the die cavity and the panel is incrementally deformed radially into the concave surfaces between the frustoconical side wall and the flange portion providing improved torque resistance.