Method for the Production of a Peripherally Closed Hollow Profile Section

Abstract

A method is provided for producing peripherally closed hollow profile section using fluidic internal high pressure. A hollow profile section blank is inserted into a cavity of an internal high pressure forming tool and thereafter being pressed mechanically into an intermediate form approximate to the final form of the hollow profile section, after which, with the tool closed, the intermediate form of the blank is expanded into the final form of the hollow profile section. The blank used in terms of its peripheral length, possesses oversize with respect to the peripheral length of the forming tool cavity. Moreover, the blank material which is excess with respect to the blank material required for the hollow profile section blank to come to bear completely against the cavity of the forming tool is pushed into the blank interior, so as to form an indentation, at the earliest during the pressing operation.

1 - 3 . (canceled)  
     
     
         4 . A method for producing a peripherally closed hollow profile section using fluidic internal high pressure, comprising inserting a hollow profile section blank into a cavity of an internal high pressure forming tool, then pressing the blank mechanically into an intermediate form approximating a final form of the hollow profile section, and thereafter, with the tool in a closed position, expanding the intermediate form of the blank into the final form of the hollow profile section using the internal high pressure, wherein the hollow profile section blank, in terms of a peripheral length thereof, possesses oversize with respect to a peripheral length of the forming tool cavity, and the hollow profile section blank is pressed into the intermediate form which, with the blank material which is excess with respect to the blank material required for the hollow profile section blank to come to bear completely against the cavity of the forming tool, overshoots a limit of the forming space reproducing the final form of the hollow profile section, with the excess blank material then being pushed into the blank interior so as to form an indentation early during the pressing operation.  
     
     
         5 . The method as claimed in  claim 4 , wherein the pressing-in operation occurs after the formation of the intermediate form by a moveable forming element which remains in the press-in position during the internal high pressure forming.  
     
     
         6 . The method as claimed in  claim 4 , wherein the hollow profile section blank is filled with pressure fluid before the pressing-in operation.  
     
     
         7 . The method as claimed in  claim 5 , wherein the pressing-in operation occurs after the formation of the intermediate form by a moveable forming element which remains in the press-in position during the internal high pressure forming.