Daimler Chrysler Ag

Daimler Ag

Stephan Kuschel

Stefan Schwarz

In a method for the production of a rim hole in hollow profiles, a tubular piece is pushed into the hollow profile and placed there in such a way that it coaxially surrounds the location of the rim hole to be produced. The hollow profile is then acted upon from outside to inside at this location by a tool, with the rim hole being formed. In order to make possible a rim hole in hollow profiles in a relatively simple manner, this rim hole also satisfying high strength requirements even in the case of a small wall thickness of the hollow profile, it is proposed to first punch two opposite holes out of the hollow profile. At least one of these holes has a diameter which is smaller than that of the rim hole to be produced. The tubular piece is then inserted into the hollow profile interior, so that it comes to lie there coaxially to the common axis of the holes. The hollow profile material of the hollow profile section located between the hole edge and the inside of the tubular piece is then drawn into the hollow profile interior by at least one punch until it bears flat against the inside of the tubular piece.

Method for the production of a rim hole in hollow profiles

The invention relates to a method and apparatus for the production of double-walled hollow sections by means of internal high-pressure forming, a first hollow section being inserted into a second hollow section, after which the double-walled hollow section thus formed is subjected to high internal fluid pressure in such a way in an internal high-pressure forming die that the double-walled hollow section is expanded. During this process, an air gap is formed between the first, inner, hollow section and the second, outer, hollow section. In order to produce double-walled hollow sections with an air gap between the inner and the outer hollow section in a simple manner and with a reduced process time, the proposal is to position the inner hollow section in a defined manner in the outer hollow section during insertion, forming a gap, to introduce an intermediate layer between the inner hollow section and the outer hollow section, filling the gap, and, after expansion of the double-walled hollow section by internal high-pressure forming, to dissolve the intermediate layer out of the hollow section via an opening formed at least in one of the hollow sections, opening up the gap as an air gap.

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Hamburg, Germany

Stephan Kuschel