Method for producing hollow bodies, profile for use in said method, hollow body, assembly unit and mold

Method in accordance with one of the preceding claims, characterized in that in a further method, step an indenting process is carried out at the free exposed end face of the ring projection to produce a breakaway edge (94) for the piercing slug (96) during the subsequent piercing.

Method in accordance with one of the preceding claims, characterized in that a dilation process is carried out after the piercing in order to provide the pierced projection (36;

• 236) with an outer wall (106;
• 306) which diverges substantially conically in the direction of its free end face.

Method in accordance with one of the preceding claims, characterized in that the respective method steps are carried out in a stamping press (36) using progressive tooling (26).

Hollow body element, characterized in that it has an at least substantially rectangular central region (417) and, to the left and right of this, wings (419, 421) integral therewith which extend at the component side (412) beyond the central region and there form two bars (414, 416) which extend parallel to the longitudinal sides (420) of the section and merge via an inclined recess (423, 425) into the lower side of the central region of the section, with the top sides (427, 429) of the wings having a clear spacing from the top side of the central region of the section and hereby forming shoulders which extend obliquely to the side walls of the central region and include an angle (a) with one another which, in relation to the side of the section remote from the component side is somewhat smaller than 180°, for example lies in a range of 175° to 160°.

Hollow body element in accordance with one of the preceding claims, characterized in that the end of the ring-like piercing section has a conical recess (102) forming a chamfer which diverges going in the direction of the free end face of the piercing section.

Die in particular for use with a hollow body element having two grooves at the component side which extend parallel to another and form the bars, characterized in that the end face (320) of the die is provided with two bar-like projections (246;

• 248) extending parallel to one another at its end face confronting the component, with the bar-like projections having a maximum width which corresponds at least substantially to the width of the U-shaped grooves (223, 225) of the hollow body element less twice the thickness of the component and a length which corresponds at least substantially to the length of the U-shaped grooves and in that the die has a ring projection between the bars which brings about a deformation of the component into an undercut formed around the piercing section of the hollow body element and a central bore (324) which cooperates with a ring-like piercing section (236) of the hollow body element in order bring about a piercing slug from the component during the attachment of the hollow body element to the component.