Method of Forming a Circular Sheet-Metal Blank

Abstract

A method of forming a circular sheet-metal blank which rests on a tool rotating about an axis. The sheet-metal blank has a thickness and has a diameter which is small than a diameter of the tool.

1 . A method of forming a circular sheet-metal blank, the method steps comprising:
 providing a tool rotatable about an axis, the tool having a tool diameter;   providing a circular sheet-metal blank, the sheet-metal blank resting on the tool and having an initial thickness and an initial diameter that is smaller than the tool diameter;   providing a flow-forming roller;   plunging the free-forming roller into material of the circular sheet-metal blank; and   moving the free-forming roller radially outward such that an area of the circular sheet-metal blank is enlarged radially in all directions to form a rotationally symmetrical circular sheet-metal blank having a resulting thickness that is smaller than the initial thickness at least in sections of the sheet-metal blank and a resulting diameter that is larger than the initial diameter.   
   
   
       2 . The method according to  claim 1 , wherein the circular sheet-metal blank includes a central holes. 
   
   
       3 . The method according to  claim 1 , wherein the circular sheet-metal blank is held on the tool. 
   
   
       4 . The method according to  claim 1 , wherein the moving of the flow-forming roller radially outward is repeated several times. 
   
   
       5 . The according to  claim 1 , wherein the resulting diameter is larger than the initial diameter by more than 5%. 
   
   
       6 . The method according to  claim 1 , wherein the resulting diameter is larger than the initial diameter by more than 10%. 
   
   
       7 . The method according to  claim 1 , wherein the resulting diameter is larger than the initial diameter by more than 20%. 
   
   
       8 . The method according to  claim 1 , wherein a drifting of the material of the circular sheet-metal blank in the axial direction is prevented by one or more freely rotatable hold-down rollers. 
   
   
       9 . (canceled) 
   
   
       10 . The method according to  claim 1 , wherein the formed symmetrical sheet-metal blank includes a waste circular blank used in wheel tire production. 
   
   
       11 . The method according to  claim 1 , wherein the formed symmetrical sheet-metal blank includes a gear part. 
   
   
       12 . The method according to  claim 1 , wherein the formed symmetrical sheet-metal blank includes a flywheel ring gear. 
   
   
       13 . The method according to  claim 1 , further including the step of providing a plurality of flow-forming rollers.