Method and apparatus for manufacturing a rim bed by means of cold forming

Abstract

A method for manufacturing a substantially rotationally symmetric rim bed having a wall thickness varying along the longitudinal axis by means of cold forming, wherein the side walls of a substantially cylindrical metal bed having a substantially constant wall thickness are flared radially outwards in a pressing operation, and wherein the wall thickness of the flared side walls is varied along the longitudinal axis by means of flow-spinning, with axial stretching and profiling of the sides. The invention further relates to an apparatus for manufacturing a rim bed by means of cold forming.

1 . A method for manufacturing a substantially rotationally symmetric rim bed having a wall thickness varying along the longitudinal axis by means of cold forming, wherein the side walls of a substantially cylindrical metal bed having a substantially constant wall thickness are flared radially outwards in a pressing operation, and wherein the wall thickness of the flared side walls is varied along the longitudinal axis by means of flow-spinning, with axial stretching and profiling of the sides. 
   
   
       2 . A method according to  claim 1 , wherein, during flow-spinning, the flared side walls of the bed are pressed down from a free position on a mandrel. 
   
   
       3 . A method according to  claim 1 , wherein, during flow-spinning, in a first flow-spinning step, the bed is pressed down on a mandrel near the center of the length of the longitudinal axis. 
   
   
       4 . A method according to  claim 3 , wherein, during flow-spinning, in a second processing step, the bed is axially stretched, radially thinned and profiled from the center area of the longitudinal axis in two opposite, outwardly directed movements with radial pressing down on a mandrel. 
   
   
       5 . A method according to,  claim 1  wherein the pre-profiled, flow-spun bed is rolled to a rim bed by means of roll forming. 
   
   
       6 . A method according to  claim 1 , wherein the bed is only radially expanded after flow-spinning and optionally roll forming. 
   
   
       7 . An apparatus for manufacturing a substantially rotationally symmetric rim bed having a wall thickness varying along the longitudinal axis by means of cold forming, wherein a substantially cylindrical metal bed having a substantially constant wall thickness is provided with sides flared radially outwards in a pressing operation, and wherein the wall thickness of the flared sides is varied along the longitudinal axis by means of flow-spinning, with axial stretching and profiling of the sides. 
   
   
       8 . An apparatus according to  claim 7 , wherein, during flow-spinning, the flared side walls of the bed are pressed down from a free position on a mandrel. 
   
   
       9 . An apparatus according to  claim 8 , wherein a pressing station is provided for radially outward flaring of the sides of a cylindrical bed. 
   
   
       10 . An apparatus according to  claim 8 , wherein a flow-spinning station is provided for profiling and axially stretching the flared bed. 
   
   
       11 . An apparatus according to  claim 10 , wherein the flow-spinning station connects downstream to the pressing station. 
   
   
       12 . An apparatus according to  claim 10 , wherein the flow-spinning station is located upstream of a rolling station for rolling the pre-profiled, flow-spun bed to a rim bed.