Method and device for forming a workpiece

Abstract

A device ( 1 ) for forming a hollow and at least essentially rotation-symmetric workpiece ( 4 ), having an inner forming tool ( 3 ) for supporting an inner contour of the workpiece ( 4 ) and an outer forming tool ( 2 ) for introducing a forming force into an outer contour ( 10 ) of the workpiece ( 4 ). The workpiece ( 4 ) can be rotated relative to the outer forming tool ( 2 ) around an axis of rotation (X). The device ( 1 ) has a machining tool ( 15 ) and is designed such that the machining tool ( 15 ) can act upon the outer contour ( 10 ) of the workpiece ( 4 ) at the same time as the forming tool ( 2 ) in order to insure that the diameter of the workpiece ( 4 ) is uniform before the workpiece ( 4 ) is acted upon by the forming tool ( 2 ) to prevent whip arm or curvature in the workpiece ( 4 ).

1 . A device ( 1 ) for forming a hollow and at least essentially rotation-symmetric workpiece ( 4 ), the device ( 1 ) having an inner forming tool ( 3 ) for supporting an inner contour of the workpiece ( 4 ) and an outer forming tool ( 2 ) for introducing a forming force into an outer contour ( 10 ) of the workpiece ( 4 ), wherein the workpiece ( 4 ) can be rotated relative to the outer forming tool ( 2 ) around an axis of rotation (X), characterized in that the device ( 1 ) has a machining tool ( 15 ) located proximate the workpiece ( 4 ) and proximate the outer forming tool ( 2 ) and wherein the machining tool ( 15 ) is configured such that the machining tool ( 15 ) acts upon a predetermined portion of the outer contour ( 10 ) of the workpiece ( 4 ) prior to said predetermined portion of the outer contour ( 10 ) being acted upon by said forming tool ( 2 ) and at the same time as the forming tool ( 2 ) is acting upon a prior predetermined portion of the outer contour ( 10 ) previously acted upon by said machining tool ( 15 ). 
     
     
         2 . The device ( 1 ) as in  claim 1 , characterized in that the forming tool ( 2 ) has a forming roll. 
     
     
         3 . The device ( 1 ) as in  claim 2 , characterized in that the forming tool ( 2 ), in particular the forming roll has a surface for transferring the forming forces to the workpiece ( 4 ) and is designed such that the axial movement of the workpiece ( 4 ) causes an increasing displacement of the material of the workpiece ( 4 ) relative to the outer forming tool ( 2 ) in the direction of the inner forming tool ( 3 ). 
     
     
         4 . The device ( 1 ) as in  claim 1 , characterized in that the device ( 1 ) has a plurality of outer forming tools ( 2 ) preferably arranged opposite relative to the inner forming tool ( 3 ). 
     
     
         5 . The device ( 1 ) as in  claim 1 , characterized in that the machining tool ( 15 ) acts upon the outer contour ( 10 ) of the workpiece ( 4 ) by removing swarfs of workpiece material, and wherein the device ( 1 ) has a swarf suction device for removing the swarfs arising at the machining tool ( 15 ). 
     
     
         6 . The device ( 1 ) as in  claim 1 , characterized in that the device ( 1 ) further includes a cooling apparatus for applying a cooling agent in an area of the forming tool ( 2 ) and/or of the machining tool ( 15 ) acting upon the workpiece ( 4 ). 
     
     
         7 . The device ( 1 ) as in  claim 1 , characterized in that an axial distance ( 16 ) between the outer forming tool ( 2 ) and the machining tool ( 15 ) can be adjusted. 
     
     
         8 . The device ( 1 ) as in  claim 1 , characterized in that an effective area of the forming tool ( 2 ) is located in an axial direction in an area of an end zone of the inner forming tool ( 3 ). 
     
     
         9 . A method for forming a hollow and at least essentially rotation-symmetric workpiece ( 4 ), wherein the workpiece ( 4 ) relative to an outer forming tool ( 2 ) is put in rotation around an axis of rotation (X), which at least approximately corresponds to its axis of symmetry, wherein the outer forming tool ( 2 ) acts upon an outer contour ( 10 ) of the workpiece ( 4 ) and through exerting a forming force onto the outer contour ( 10 ) of the workpiece ( 4 ) plastically deforms the workpiece ( 4 ), wherein the workpiece ( 4 ) with its inner contour is supported on an inner forming tool ( 3 ), wherein the workpiece ( 4 ) carries out a feed movement parallel to the axis of rotation relative to the outer forming tool ( 2 ), characterized in that machining of an area of the outer contour ( 10 ) of the workpiece ( 4 ) yet to be formed takes place during forming of a prior machined area. 
     
     
         10 . The method as in  claim 9 , characterized in that the superimposition of the rotation and the feed movement results in a helical track along which the outer forming tool ( 2 ) acts upon the workpiece ( 4 ). 
     
     
         11 . The method as in  claim 9 , characterized in that at least during forming of an axial section of the workpiece ( 4 ), machining occurs with unevenly distributed material removal across the circumference of the outer contour ( 10 ) workpiece ( 4 ). 
     
     
         12 . The method as in  claim 9 , characterized in that machining eliminates an eccentricity of the outer contour ( 10 ) of the workpiece ( 4 ) relative to the axis of rotation (X). 
     
     
         13 . The method as in  claim 9 , characterized in that initially an axial area, preferably an end zone of a workpiece is formed using the forming tool such that the formed area with its inner contour comes to rest on the inner forming tool ( 3 ) prior to the start of machining. 
     
     
         14 . The method as in  claim 13 , characterized in that the workpiece ( 4 ) is shifted in axial direction beyond the end zone of the inner forming tool ( 3 ) through a feed movement. 
     
     
         15 . The method as in  claim 9 , characterized in that the length of the workpiece ( 4 ) increases in axial direction through the plastic deformation. 
     
     
         16 . The method as in  claim 9 , characterized in that a wall thickness ( 7 ,  8 ) of the workpiece ( 4 ), a circumference of the outer contour ( 10 ) of the workpiece ( 4 ) and/or a circumference of the inner contour of the workpiece ( 4 ) is reduced through the plastic deformation. 
     
     
         17 . The method of  claim 9  wherein said machining of an area of the outer contour ( 10 ) of the workpiece ( 4 ) yet to be formed takes place during forming of a prior machined area is performed by a machining tool ( 15 ) that is configured such that the machining tool ( 15 ) acts upon a predetermined portion of the outer contour ( 10 ) of the workpiece ( 4 ) prior to said predetermined portion of the outer contour ( 10 ) being acted upon by said forming tool ( 2 ) and at the same time as the forming tool ( 2 ) is acting upon a prior predetermined portion of the outer contour ( 10 ) previously acted upon by said machining tool ( 15 ).