Method for shaping a bent single- or multiple-chamber hollow profile internal high pressure

Abstract

A method for manufacturing bent hollow bodies with inner and outer arcs forming inner arc wall regions and outer arc wall regions. The method including bending a starting hollow body, and, using at least one high internal pressure (HIP) forming process step, transforming the hollow body in an HIP tool to a final cross-sectional shape. The starting hollow body exhibits a readily bent cross-section at least in a region to be bent, in which by means of specific cross-sectional shaping, wall material lies closer to a neutral stress plane with reference to bending stresses than in the final cross-sectional shape. The HIP tool has a slide element. The method includes moving the slide element in the inner arc wall region of the bent starting hollow body, making contact at least with part of a surface area of the inner arc wall region, and withdrawing the slide element during the HIP process in the inner arc wall region in a direction of an opening of the bend, whereby the inner arc wall region of the bent starting hollow body is displaced in a direction of the withdrawing slide element by action of the high internal pressure.

1 - 15 . (canceled)  
     
     
         16 . A method for manufacturing bent hollow bodies with inner and outer arcs forming inner arc wall regions and outer arc wall regions, comprising the steps of: bending a starting hollow body; and, using at least one high internal pressure (HIP) forming process step, transforming the hollow body in an HIP tool to a final cross-sectional shape, whereby the starting hollow body exhibits a readily bent cross-section at least in a region to be bent, in which by means of specific cross-sectional shaping, wall material lies closer to a neutral stress plane with reference to bending stresses than in the final cross-sectional shape, the HIP tool having a slide element, the method including moving the slide element in the inner arc wall region of the bent starting hollow body, making contact at least with part of a surface area of the inner arc wall region, and withdrawing the slide element during the HIP process in the inner arc wall region in a direction of an opening of the bend, whereby the inner arc wall region of the bent starting hollow body is displaced in a direction of the withdrawing slide element by action of the high internal pressure.  
     
     
         17 . The method according to  claim 16 , including controlling the withdrawal of the slide element and the high internal pressure so that wall material flows along a surface of the slide element from the inner arc wall region in a direction of an adjacent, bending distal wall zone of the hollow body.  
     
     
         18 . The method according to  claim 16 , including shape forming the hollow body in the outer arc wall region into the final cross-sectional shape and, subsequently, withdrawing the slide element from the inner arc wall range.  
     
     
         19 . The method according to  claim 16 , wherein during the withdrawing the slide element the inner arc wall region of the bent starting hollow body is shape-formed at least close to the final cross-sectional shape and, by a further HIP process, the hollow body is transformed to the shape of the final hollow body in a further tool having the cross-sectional shape of the final hollow body.  
     
     
         20 . The method according to  claim 16 , wherein at least in the inner arc wall region the bent starting hollow body has a recess which, viewed from outside, is concave in form.  
     
     
         21 . The method according to  claim 16 , wherein the bent starting hollow body is a simple hollow section, and the readily bent cross-sectional shape exhibits two recesses that are counter to each other in shape and form a necking region.  
     
     
         22 . The method according to  claim 16 , wherein the final hollow body is a simple hollow section.  
     
     
         23 . The method according to  claim 22 , wherein the final hollow body is a tube-shaped hollow section.  
     
     
         24 . The method according to  claim 23 , wherein the tube-shaped hollow section has a circular cross-section at an end.  
     
     
         25 . The method according to  claim 23 , wherein the tube-shaped hollow section has an oval cross-section at an end.  
     
     
         26 . The method according to  claim 16 , wherein the hollow body is a metal hollow body and a ratio B of an average bending radius R m  to an outer diameter D of the bent final hollow body lies in a range:  
         0.5 ≦R   m   /D≦ 2.  
     
     
         27 . The method according to  claim 26 , wherein the hollow body is made of aluminum.  
     
     
         28 . The method according to  claim 26 , wherein the hollow body is made of an aluminum alloy.  
     
     
         29 . The method according to  claim 26 , wherein the ratio B is in a range:  
         0.7 ≦R   m   /D≦ 1.  
     
     
         30 . The method according to  claim 16 , wherein a bending angle of the bent final hollow body lies in a range of 40° to 180°.  
     
     
         31 . The method according to  claim 30 , wherein the bending angle lies in a range of 60° to 180° C.  
     
     
         32 . The method according to  claim 31 , wherein the bending angle lies in a range of 90° to 180°.  
     
     
         33 . A device for forming bent starting hollow bodies to a final cross-sectional shape or a cross-sectional shape approaching that of a final hollow section using a high internal pressure (HIP) process, whereby a starting hollow body exhibits a readily bent cross-section at least in a region to be bent, in which by means of specific cross-sectional shaping, wall material lies closer to a neutral stress plane with reference to bending stresses than in the final cross-sectional shape, the device comprising an HIP tool configured to accommodate the bent starting hollow body, the HIP tool having a slide element situated in an inner arc wall region of the bent starting hollow body, the slide element being arranged to be movable in a direction of an opening of the bend so that the slide element is withdrawn.  
     
     
         34 . The device according to  claim 33 , wherein the shape-forming tool is a multi-part tool with upper and lower halves and the slide element.  
     
     
         35 . The device according to  claim 33 , wherein the slide element is arranged to lie in a supportive manner at least on part of a surface of the inner arc wall region.  
     
     
         36 . The device according to  claim 33 , wherein the bent starting hollow body exhibits a recess at least in the inner arc wall region, the slide element having a face that faces the inner arc wall region of the starting hollow body, the face having a convex shape which is counter-identical to a shape of the recess.  
     
     
         37 . The device according to  claim 33 , wherein, in plan view, the slide element is tongue-shaped.