Process for manufacturing a light alloy wheel rim and wheel rim resulting therefrom

Abstract

Process for manufacturing a wheel rim in light alloy including the following operations: providing a rough wheel rim in light alloy, comprising a wheel disc and an annular portion, the annular portion including a first and a second bead defining a drop well having a first profile; processing the rough wheel rim, modifying the first profile in order to obtain a second profile being of a lower thickness than the first profile, at least at an intermediate portion of the drop well, characterised by including a finishing operation of a surface of the second profile intermediate portion by means of a compression action of said surface, the finishing operation leaving the low thickness substantially unchanged.

1 . A method for producing an alloy wheel rim comprising the steps of:
 (a) subjecting an alloy wheel rim, the wheel rim having an annular portion including a first bead and a second bead and defining a drop well, wherein the drop well includes a first hump arranged in the vicinity of the first bead and a second hump arranged in the vicinity of the second bead, wherein the drop well includes an intermediate portion disposed substantially between the first and second humps, and wherein the intermediate portion extends substantially along an entire width of the drop well of the wheel rim between the first and second humps, wherein the drop well of the wheel rim initially includes a first profile which defines a first thickness, to a processing operation wherein the first profile is processed to produce a second profile having a second thickness which is less than the first thickness of the first profile, at least at the intermediate portion of the drop well of the wheel rim; and   (b) following step (a), subjecting the entirety of the surface of the intermediate portion of the second profile of the drop well of the wheel rim to a superficial surface finishing operation, wherein the superficial surface finishing operation plastically deforms the surface of the intermediate portion in order to substantially seal any porosities and/or holes present therein.   
     
     
         2 . The method of  claim 1 , wherein the superficial surface finishing operation leaves the second thickness of the second profile substantially unchanged. 
     
     
         3 . The method of  claim 1 , wherein the superficial surface finishing operation includes a number of local compression actions acting on limited areas of the surface. 
     
     
         4 . The method of  claim 1 , wherein the superficial surface finishing operation includes a burnishing operation of the surface. 
     
     
         5 . The method of  claim 4 , wherein the burnishing operation is performed on the wheel rim by at least one tool including a local compression element having a smaller size than the surface. 
     
     
         6 . The method of  claim 1 , wherein the surface is a surface facing towards the outside of the wheel rim. 
     
     
         7 . The method of  claim 1 , wherein the surface is a surface facing towards the inside of the wheel rim. 
     
     
         8 . The method of  claim 1 , wherein the surface includes a first surface facing towards the outside of the wheel rim and a second surface facing towards the inside of the wheel rim, the superficial surface finishing operation being performed by at least two tools acting on the first and second surface respectively in a simultaneous way on areas corresponding to the first and second surfaces. 
     
     
         9 . The method of  claim 1 , wherein the surface includes a first surface facing towards the outside of the wheel rim and a second surface facing towards the inside of the wheel rim, the superficial surface finishing operation being performed by at least two tools acting on the first and second surface respectively in a simultaneous way on zones of the first and second surfaces staggered to one another. 
     
     
         10 . The method of  claim 1 , wherein the wheel rim is produced by one of an in-die casting operation and a casting operation. 
     
     
         11 . The method of  claim 1 , wherein the second profile is produced by a turning operation. 
     
     
         12 . The method of  claim 1 , wherein at least one of the first profile includes an intermediate portion having a first thickness of between 10 millimeters and 20 millimeters and the second thickness is less than 4 millimeters. 
     
     
         13 . An alloy wheel rim produced according to the method of  claim 1 . 
     
     
         14 . A method for producing an alloy wheel rim comprising the steps of:
 subjecting an alloy wheel rim, the wheel rim having an annular portion including a first bead and a second bead and defining a drop well, wherein the drop well includes a first hump adjacent the first bead and a second hump adjacent the second bead and an intermediate portion extending substantially along an entire width thereof between the first and second humps, wherein the drop well of the wheel rim initially includes a first profile which defines a first thickness, to a processing operation wherein the first profile is processed to remove material from only the intermediate portion of the drop well thereof and produce a second profile at the drop well having a second thickness which is less than the first thickness of the first profile.   
     
     
         15 . The method of  claim 14  wherein the second profile of the wheel rim is subjected to a processing operation by subjecting the entirety of the surface of the intermediate portion of the second profile of the drop well of the wheel rim to a superficial surface finishing operation, wherein the superficial surface finishing operation leaves the second thickness of the second profile substantially unchanged. 
     
     
         16 . The method of  claim 14 , wherein the wheel rim is produced by one of an in-die casting operation and a casting operation. 
     
     
         17 . The method of  claim 14 , wherein the second profile is produced by a turning operation. 
     
     
         18 . The method of  claim 14 , wherein at least one of the first profile includes an intermediate portion having a first thickness of between 10 millimeters and 20 millimeters and the second thickness is less than 4 millimeters. 
     
     
         19 . An alloy wheel rim produced according to the method of  claim 14 . 
     
     
         20 . A method for producing an alloy wheel rim comprising the steps of:
 (a) subjecting an alloy wheel rim, the wheel rim having an annular portion including a first bead and a second bead and defining a drop well, wherein the drop well includes a first hump arranged near the first bead and a second hump arranged near the second bead, wherein the drop well includes an intermediate portion between the first and second humps, and wherein the intermediate portion extends substantially along an entire width of the drop well of the wheel rim between the first and second humps, wherein the drop well of the wheel rim initially includes a first profile which defines a first thickness, to a turning operation, wherein the first profile is processed to produce a second profile having a second thickness which is less than the first thickness of the first profile, at least at the intermediate portion of the drop well of the wheel rim; and   (b) following step (a), subjecting the entirety of the surface of the intermediate portion of the second profile of the drop well of the wheel rim to a burnishing operation to deform the surface of the intermediate portion and substantially seal any porosities and/or holes present therein.