Tubular axle beam

Abstract

A tubular axle beam with variable wall thickness for a vehicle is provided including a first beam portion extending longitudinally between first ends and including spaced apart first longitudinal edges. A second beam portion extends longitudinally between second ends and includes spaced apart second longitudinal edges. Weld beads secure the first longitudinal edges to the second longitudinal edges to define a cavity between the beam portions with the first and second ends arranged adjacent to one another. Preferably, the tubular axle beam is constructed by stamping a first blank to form a first half of the beam, and a second blank is stamped to form a second half of the beam. The first and second portions are welded to one another to define a cavity between the portions. In another embodiment of the invention, a tubular axle beam includes a hollow beam extending longitudinally between opposing ends. A reinforcing sleeve is arranged concentric to the hollow beam between the ends with the reinforcing sleeve secured to the hollow beam, preferably, by weld beads. The hollow beam and reinforcing sleeve initially may be cylindrical tubes that are secured to one another. Subsequently the hollow beam and reinforcing sleeve may be bent into a desired shape and then further formed using a hydroforming or other process to obtain cross-sectional areas of various shapes along the length of the beam.

What is claimed is:  
     
         1 . A method of forming a tubular axle beam, comprising the steps of: 
 a) stamping a first variable thickness blank to form a first portion of the beam;    b) stamping a second variable thickness blank to form a second portion of the beam; and    c) welding the first and second portions to one another to define a cavity between the portions.    
     
     
         2 . The method according to  claim 1 , further including step d) securing a king pin boss to an end of the beam.  
     
     
         3 . The method according to  claim 1 , wherein step a) includes forming a U-shaped cross-section in a central portion of the first portion.  
     
     
         4 . The method according to  claim 1 , wherein step a) includes forming an arcuate cross-section in an end portion of the first portion.  
     
     
         5 . The method according to  claim 3 , wherein step b) includes forming a U-shaped cross-section in a central portion of the second portion similar in shape to U-shaped cross-section of the first portion.  
     
     
         6 . The method according to  claim 4 , wherein step b) includes forming an arcuate cross-section in an end portion of the second portion similar in shape to U-shaped cross-section of the first portion.  
     
     
         7 . The method according to  claim 3 , wherein step a) includes forming an arcuate cross-section in an end portion of the first portion.  
     
     
         8 . A tubular axle beam for a vehicle comprising: 
 a first variable thickness beam portion extending longitudinally between first ends and including spaced apart first longitudinal edges;    a second variable thickness beam portion extending longitudinally between second ends and including spaced apart second longitudinal edges; and    weld beads securing said first longitudinal edges to said second longitudinal edges to define a cavity between said beam portions with said first and second ends arranged adjacent to one another.    
     
     
         9 . The beam according to  claim 8 , further including a central portion having a generally square cross-section.  
     
     
         10 . The beam according to  claim 8 , further including opposing end portions having a generally circular cross-section.  
     
     
         11 . The beam according to  claim 8 , further including king pin bosses secured to opposing end portions of said beam.  
     
     
         12 . A method of forming a tubular axle beam, comprising the steps of: 
 a) providing a hollow beam;    b) arranging a reinforcing sleeve concentrically relative to a portion of the hollow beam;    c) securing the reinforcing sleeve to the hollow beam; and    d) forming the hollow beam and reinforcing sleeve into a desired tubular axle beam.    
     
     
         13 . The method according to  claim 12 , wherein step c) includes welding the reinforcing sleeve to the hollow beam.  
     
     
         14 . The method according to  claim 12 , wherein step d) includes bending the hollow beam and reinforcing sleeve into a desired tubular axle beam shape.  
     
     
         15 . The method according to  claim 14 , wherein step d) further includes hydroforming the hollow beam and reinforcing sleeve to obtain desired cross-sections along a length of the tubular axle beam.  
     
     
         16 . The method according to  claim 15 , wherein step d) includes forming a generally square cross-section along a central portion of the tubular axle beam.  
     
     
         17 . The method according to  claim 15 , wherein step d) includes forming a generally circular cross-section along opposing end portions of the tubular axle beam.  
     
     
         18 . A tubular axle beam for a vehicle comprising: 
 a hollow beam extending longitudinally between ends; and    a reinforcing sleeve arranged concentrically with said hollow beam between said ends with said reinforcing sleeve secured to said hollow beam.    
     
     
         19 . The beam according to  claim 18 , wherein said hollow beam includes an outer surface and said reinforcing includes an inner surface, said surfaces in abutting relationship with one another.  
     
     
         20 . The beam according to  claim 18 , further including a plurality of reinforcing sleeves arranged concentrically with said hollow beam between said ends and secured to said hollow beam.  
     
     
         21 . The beam according to  claim 18 , further including weld beads securing said reinforcing sleeve to said hollow beam.  
     
     
         22 . The beam according to  claim 18 , wherein said hollow beam includes a length with different cross-sectional shapes along said length.  
     
     
         23 . The beam according to  claim 22 , wherein said hollow beam includes a central portion and end portions with said central portion having a generally square cross-section.  
     
     
         24 . The beam according to  claim 23 , wherein said end portions have a generally circular cross-section.