Method and a press cylinder device for producing a hollow body

Abstract

The invention relates to a flow-forming method and device for producing a hollow article having a steplike shoulder from a tubular workpiece. For this purpose on the tubular workpiece is formed a conical area, which is selectively heated. Then an axial upsetting force is exerted on the workpiece, so that the heated conical area is upset and formed to the steplike shoulder. Both the shaping of the conical area and the upsetting can be performed on one flow-forming device.

1 . Method for producing a hollow article, particularly a hollow shaft, with at least one steplike shoulder ( 20 ) from a tubular workpiece ( 10 ), in which 
 the tubular workpiece ( 40 ) is mounted on a drivable spindle ( 60 ) and is rotated,    on the tubular workpiece ( 10 ) is formed a conical area ( 12 ), which links a first workpiece section ( 14 ) having a larger diameter with a second workpiece section ( 16 ) having a smaller diameter, and    the conical area ( 12 ) is formed to the steplike shoulder ( 20 ),    charakterized in that 
 after forming of the conical area ( 12 ), it is selectively heated,  
 by means of a tailstock an axial upsetting force is exerted on the workpiece ( 10 ) and  
 the heated concial area ( 12 ) is pushed together by the axial upsetting force exerted by the tail stock and under the simultaneous action of at least one spinning roller ( 42 ) is formed to the steplike shoulder ( 20 ), the spinning roller ( 42 ) defining the contour of the desired shoulder ( 20 ) .  
   
     
     
         2 . Method according to  claim 1 , characterized in that the conical area ( 12 ) of the tubular workpiece ( 10 ) as produced by flow-forming in a flow-forming machine.  
     
     
         3 . Method according to  claim 2 , characterized in that the heating and axial upsetting of the conical area ( 12 ) in the flow-forming machine is performed in the same setting as the flow-forming.  
     
     
         4 . Method according to one of the  claims 1  to  3 , characterized in that a wall thickness increase is formed selectively on the steplike shoulder ( 20 ) during the shaping of the latter.  
     
     
         5 . Method according to one of the  claims 1  to  4 , characterized in that during the shaping of the steplike shoulder ( 20 ) a mandrel ( 50 ) is introduced into the workpiece ( 10 ) and predetermines an inner contour of the shoulder ( 20 ).  
     
     
         6 . Method according to one of the  claims 1  to  5 , characterized in that several steplike shoulders ( 20 ) are formed on a workpiece ( 10 ).  
     
     
         7 . Flow-forming device, particularly for forming a hollow article according to one of the  claims 1  to  6 , having 
 a spindle ( 60 ) drivable in rotary manner,  
 a retaining device ( 62 ) fitted thereto for the non-rotary retention of a tubular workpiece ( 10 ) on the spindle ( 60 ),  
 a spinning mandrel ( 50 ) with an outer contour adapted to an inner contour of the workpiece ( 10 ) and  
 a tail stock, which is axially adjustable relative to the spindle ( 60 ),  
 Characterized in that 
 a mechanism ( 44 ) is provided for the selective heating of a workpiece area and  
 the tail stock is constructed for exerting an axial upsetting force on the workpiece.  
 
 
     
     
         8 . Flow-forming device according to  claim 7 , characterized in that the spinning mandrel ( 50 ) is located on the tail stock and a stop member for transferring the upsetting force is provided on the tail stock.  
     
     
         9 . Flow-forming device according to  claim 7  or  8 , characterized in that at its free end the spinning mandrel ( 50 ) has a draw-in mandrel section ( 72 ), which is located on the spinning mandrel ( 50 ) accompanied by the formation of a steplike shoulder ( 74 ) serving as a stop.  
     
     
         10 . Flow-forming device according to one of the  claims 7  to  9 , characterized in that the retaining device ( 62 ) has a driving tooth system ( 64 ), in which can be axially formed the workpiece ( 10 ) for producing a non-rotary connection.