Vehicle Axle

Abstract

A traverse strut for use in a twist beam axle assembly is provided. The traverse strut extends along a length and presents a central section; a pair of end sections; and a pair of intermediate sections between the central section and the respective end sections. At least a portion of the central section has a first wall thickness, at least a portion of each end section has a second wall thickness that is greater than the first wall thickness and at least a portion of each intermediate section has a third wall thickness that is greater than the second wall thickness. Additionally, at least two of the central, intermediate and end sections is work hardened. The transverse strut has improved performance and lower weight as compared to other known transverse struts.

What is claimed is: 
     
         1 . A transverse strut for a twist axle assembly of a vehicle, comprising:
 an elongated and tubular body extending along a length between opposite end sections and having a varying wall thickness between said opposite end sections;   said elongated body including a central section disposed between said opposite end sections and a pair of intermediate sections disposed between said central section and said opposite end sections;   at least a portion of said central section of said elongated body having a first wall thickness and at least a portion of each of said end sections having a second wall thickness being greater than said first wall thickness and at least a portion of each of said intermediate sections having a third wall thickness being greater than said second wall thickness; and   wherein portions of at least two of said central, intermediate, and end sections are work-hardened.   
     
     
         2 . The transverse strut as set forth in  claim 1  wherein said central section has a generally U-shaped profile. 
     
     
         3 . The transverse strut as set forth in  claim 2  wherein said end sections have a generally circular profile. 
     
     
         4 . The transverse strut as set forth in  claim 3  wherein said intermediate sections have a generally U-shaped profile adjacent said central section and a generally circular profile adjacent the respective end section and gradually changes in shape from said central section to the respective end section. 
     
     
         5 . The transverse strut as set forth in  claim 1  wherein said central section has said first wall thickness along substantially its entire length and said end sections have said second wall thickness along substantially their entire lengths. 
     
     
         6 . The transverse strut as set forth in  claim 1  wherein said tubular body has an outer surface that is deformed to give said tubular body its varying wall thickness. 
     
     
         7 . The transverse strut as set forth in  claim 1  wherein said tubular body has an inner surface that is deformed to give said tubular body its varying wall thickness. 
     
     
         8 . A method of making a transverse strut for a twist rear axle assembly, comprising the steps of:
 sliding a preform having a generally cylindrical shape onto a mandrel and wherein the preform extends a predetermined length along an axis between opposite ends;   rotating the preform about the axis;   deforming the material of the preform in an axial direction with at least one roller during the rotating of the preform about the axis to produce a tubular body having a central section, a pair of end sections, and a pair of intermediate sections between the end sections and wherein at least a portion of the central section has a first wall thickness and at least a portion of each of the end sections has a second wall thickness that is greater than the first wall thickness and at least a portion of each of the intermediate sections has a third wall thickness that is greater than the second wall thickness.   
     
     
         9 . The method as set forth in  claim 8  further including the step of pressing the central section to give it a generally U-shaped profile. 
     
     
         10 . The method as set forth in  claim 8  wherein after the deforming step the central section has the first wall thickness extending substantially entirely along its length. 
     
     
         11 . The method as set forth in  claim 8  wherein after the deforming step the end sections have the second wall thickness extending substantially entirely along their lengths. 
     
     
         12 . The method as set forth in  claim 8  wherein the tubular body after the deforming step has a greater length than the preform before the deforming step. 
     
     
         13 . The method as set forth in  claim 8  wherein the preform has a generally uniform wall thickness before the deforming step. 
     
     
         14 . The method as set forth in  claim 8  wherein the deforming step includes moving the at least one rotor in a first axial direction relative to the mandrel and wherein the deforming of the material of the preform is in the first axial direction. 
     
     
         15 . The method as set forth in  claim 8  wherein the deforming step includes moving the at least one roller in a first axial direction relative to the mandrel and wherein the deforming of the material of the preform is in a second direction opposite of the first direction.