Stamping and welding method and apparatus for forming a hollow or tubular member with high tolerances

Abstract

A method of forming a hollow metal member may include stamping a metal blank to form half shell pieces that are configured to be approximately a half of a hollow metal member and stamping a another metal blank to form a half shell piece that is configured to be approximately the other half of the hollow metal member. The half shell pieces may be aligned to place the edges of the first and second half shell pieces in abutting contact. The half shell pieces may be welded together along seams that are defined at the abutting edges of the first and second half shell pieces. The attached half shell pieces may then be compacted to form the hollow metal member with reduced residual deformation from stamping and welding the half shell pieces.

What is claimed is: 
     
         1 . A method of forming a hollow metal part, said method comprising:
 stamping a first metal blank to form a first shell piece that is configured to be a portion of a desired hollow metal part;   stamping a second metal blank to form a second shell piece that is configured to be a remaining portion of the desired hollow metal part;   aligning the first and second shell pieces to place edges of the first and second shell pieces in abutting contact;   welding the first and second shell pieces together along seams defined at the abutting edges of the first and second shell pieces to provide a non-conforming hollow part with residual deformation from stamping and welding the first and second shell pieces; and   compacting the non-conforming hollow part in a die assembly to reduce the residual deformation and form the desired hollow metal part.   
     
     
         2 . The method of  claim 1 , wherein the first shell piece is configured to be approximately a half of the desired hollow metal part and the second shell piece is configured to be approximately the other half of the desired hollow metal part. 
     
     
         3 . The method of  claim 1 , wherein the first and second shell pieces are formed to have an oversized outside profile that is greater than an outside profile of the desired hollow metal part. 
     
     
         4 . The method of  claim 3 , wherein the oversized outside profile has a diameter that is at least 1 percent greater than a corresponding diameter the outside profile of the desired hollow metal part. 
     
     
         5 . The method of  claim 1 , wherein the die assembly that compacts the non-conforming hollow part includes at least two die pieces that contact substantially entirely around an outer surface of the non-conforming hollow part. 
     
     
         6 . The method of  claim 5 , wherein an internal mandrel is disposed at a hollow area enclosed by the attached first and second half shell pieces during the compacting of the non-conforming hollow part by the at least two die pieces. 
     
     
         7 . The method of  claim 1 , wherein the desired hollow metal part includes at least one opening that is configured to be press fit with a tubular component. 
     
     
         8 . The method of  claim 1 , wherein the desired hollow metal part includes at least three openings. 
     
     
         9 . The method of  claim 1 , wherein the desired hollow metal part includes a first end opening and a second end opening, and wherein a curved section of the hollow metal part is disposed between the first and second end openings. 
     
     
         10 . An apparatus for forming a hollow metal part, said apparatus comprising:
 a stamping station configured to stamp at least one metal sheet blank to form first and second shell pieces that are configured to mate together to form a hollow metal part;   a welding station having a fixture configured to align the first and second shell pieces with edges of the first and second shell pieces in abutting contact and a welder configured to weld the first and second shell pieces together along seams defined at the abutting edges;   wherein the welding station forms the hollow metal part with a non-conforming shape due to residual deformation from stamping and welding the first and second shell pieces; and   a compacting station having at least two die pieces that together are configured to engage around an outside profile of the hollow metal part and apply inward pressure to form the hollow metal part with a desired shape.   
     
     
         11 . The apparatus of  claim 10 , wherein the desired shape of the hollow metal part has a consistent outside profile with reduced residual deformation. 
     
     
         12 . The apparatus of  claim 11 , wherein the first and second shell pieces are formed to have an oversized outside profile that is greater than the consistent outside profile of the desired shape of the hollow metal part. 
     
     
         13 . The apparatus of  claim 12 , wherein the oversized outside profile has a diameter that is at least 1 percent greater than a corresponding diameter the consistent outside profile of the desired shape of the hollow metal part. 
     
     
         14 . The apparatus of  claim 10 , wherein the first shell piece is configured to be approximately a half of the hollow metal part and the second shell piece is configured to be approximately the other half of the hollow metal part. 
     
     
         15 . The apparatus of  claim 10 , wherein the compacting station has an internal mandrel is disposed at a hollow area of the hollow metal part to prevent the inward pressure from collapsing the hollow metal part when forming the desired shape. 
     
     
         16 . A hollow metal part formed from two shell stampings, said hollow metal part comprising:
 an outer wall that extends around a hollow interior area of the hollow metal part and spans between a first end opening and a second end opening of the hollow metal part;   wherein a section of the outer wall between the first and second end openings includes a curvature that offsets the first end opening relative to the second end opening;   a pair of weld seams extending along opposing portions of the outer wall and between the first and second end openings, wherein the pair of weld seams define an attachment interface of abutting edges of shell stampings; and   wherein the outer wall has a desired shape comprising a consistent profile that is formed from a finishing compacting press that reduces residual deformation at the pair of weld seams.   
     
     
         17 . The hollow metal part of  claim 16 , wherein outer wall near at least one of the first or second end openings includes a circular shape configured to be press fit with a tubular component. 
     
     
         18 . The hollow metal part of  claim 16 , wherein the outer wall defines a third end opening, and wherein at least one of the pair of weld seams intersect the third end opening. 
     
     
         19 . The hollow metal part of  claim 16 , wherein the shell stampings are formed to have an oversized outside profile with a diameter that is at least 1 percent greater than the consistent profile that is formed from the finishing compacting press. 
     
     
         20 . The hollow metal part of  claim 19 , wherein the shell stampings defined by the weld seams are configured to be approximately a half of the desired shape of the outer wall of the hollow metal part.