Method of producing a light alloy wheel rim and an improved light alloy wheel rim for a motor vehicle

Abstract

The invention relates to a wheel rim made from a light alloy, such as an aluminium-based alloy, comprising a front face ( 10 ) and a tyre tread ( 20 ) which are welded together. The inventive method of producing the wheel rim (J) comprises the following steps: moulding of the front face ( 10 ) with a light alloy; provision of a weldable alloy strip with structural hardening; curving of said strip to produce a generally cylindrical shape; welding of the ends in relation to the curved strip with fusion of the strip material; forming of the strip by necking and/or spinning in order to form the tyre tread ( 20 ); and welding of the front face and the tyre tread to one another.

1 . A process for producing a rim (J) made of light alloy, such as an aluminum-based alloy, for a motor vehicle, the rim comprising a front face ( 10 ) and an outer rim piece ( 20 ) that are welded to each other, characterized in that it comprises the following: 
 the step of casting the front face ( 10 ) with a light alloy;    the step of providing an outer rim piece made of weldable, structural hardening alloy;    the step of bending this outer rim piece in order to give it a cylindrical general shape;    the step of welding the facing ends of the bent outer rim piece, with fusion of the material of the outer rim piece;    the step of forming the outer rim piece, by swaging and/or flowturning, in order to form the outer rim piece ( 20 ); and    the step of welding the front face and the outer rim piece to each other.    
   
   
       2 . The process as claimed in  claim 1 , characterized in that the step of forming the outer rim piece is preceded by a step of expanding the outer rim piece, after its ends have been welded together.  
   
   
       3 . The process as claimed in  claim 1  or  claim 2 , characterized in that the forming step is preceded by an at least partial solution heat treatment and quenching operation.  
   
   
       4 . The process as claimed in  claim 1 , characterized in that the weldable, structural hardening alloy is an aluminum alloy of the 6000 standard series.  
   
   
       5 . The process as claimed in  claim 1 , characterized in that the step of welding the facing ends of the outer rim piece is carried out by a welding technique chosen from the group comprising electron-beam welding, vacuum electron-beam welding, MIG (metal inert gas) welding, tandem MIG welding, laser welding and combined MIG/laser welding.  
   
   
       6 . The process as claimed in  claim 1 , characterized in that the operation of casting the front face ( 10 ) includes the formation of at least one weight-reducing hollow ( 11 ,  12 ), obtained by casting.  
   
   
       7 . The process as claimed in  claim 6 , characterized in that at least one hollow ( 11 ,  12 ) is on an inner side of the front face ( 10 ).  
   
   
       8 . The process as claimed in  claim 6 , characterized in that at least one hollow ( 11 ,  12 ) is near a connection region between the front face ( 10 ) and the outer rim piece ( 20 ).  
   
   
       9 . The process as claimed in  claim 6 , characterized in that at least one hollow ( 11 ,  12 ) opens in a demolding direction of the front face.  
   
   
       10 . A rim (J) made of light alloy, such as an aluminum-based alloy, for a motor vehicle, the rim comprising a front face ( 10 ) made of light alloy and an outer rim piece ( 20 ) also made of light alloy that are welded together, characterized in that the outer rim piece ( 20 ) is produced by bending and forming a part made of a weldable, structural hardening alloy, with the facing ends of the bent outer rim piece welded together with fusion of the material of the outer rim piece.  
   
   
       11 . The rim as claimed in  claim 10 , characterized in that the weldable, structural hardening alloy is an aluminium alloy of the 6000 standard series.  
   
   
       12 . The rim as claimed in  claim 11 , characterized in that the front face ( 10 ) includes at least one weight-reducing hollow ( 11 ,  12 ), obtained during the casting.  
   
   
       13 . The rim as claimed in  claim 12 , characterized in that at least one hollow ( 11 ,  12 ) is on an inner side of the front face.  
   
   
       14 . The rim as claimed in  claim 12 , characterized in that at least one hollow ( 11 ,  12 ) is near a connection region between the front face and the outer rim piece.  
   
   
       15 . The rim as claimed in  claim 12 , characterized in that at least one hollow ( 11 ,  12 ) opens in a demolding direction of the front face.  
   
   
       16 . The rim as claimed in  claim 10 , characterized in that it possesses two rim flanges (CJ 1 , CJ 2 ), one (CJ 1 ) of which is formed on the front face ( 10 ) and the other (CJ 2 ) of which is formed on the outer rim piece ( 20 ).