Method and Device for Producing a Peripherally Closed Hollow Profile

A method of producing a peripherally closed hollow profile having a secondary feature or a branch, said method comprising:

• shaping a hollow profile from a hollow profile blank by applying an internal high pressure whereby said hollow profile blank undergoes an expansion;
• and
• severing a cap of the secondary feature or of the branch by a counterholding punch which supports the secondary feature or the branch during the act of shaping;
• wherein the cap of the secondary feature or of the branch is severed at an internal high pressure which corresponds at most to a forming pressure for forming the hollow profile from the hollow profile blank, by a stroke of the counterholding punch in an opposite direction to an expansion direction of the hollow profile.

A device for producing a peripherally closed hollow profile having a secondary feature or a branch, comprising:

• a hydroforming tool for shaping the hollow profile;
• and
• a counterholding punch which is integrated in the hydroforming tool in a displaceable manner and supports the secondary feature or the branch during a shaping process;
• wherein
• the counterholding punch is driven so that, after the shaping of the secondary feature or of the branch, the counterholding punch plunges into said secondary feature or said branch and severs a cap of the secondary feature or of the branch by a severing contour;
• an end face of the counterholding punch runs in a continuously even manner;
• an end edge of the counterholding punch forms the severing contour;
• a passage is formed in the forming tool in which the counterholding punch is guided in a displaceable manner;
• and
• the width of an annual gap between a wall of said passage and a punch circumference corresponds approximately to a wall thickness of the secondary feature or of the branch.