Method and apparatus for producing stepped hollow shafts or stepped cylindrical hollow members by transverse rolling

Abstract

The invention relates to a method and a device for transversely rolling stepped hollow shafts or cylindrical hollow parts from a pipe. The invention achieves the object of rolling stepped hollow shafts of the most varied dimensions and also of greater lengths in a flexible manner from a pipe using a small number of simple tools. In accordance with the invention, the object is achieved by virtue of the fact that rolling tools which can be radially advanced and are disposed in a planet-like manner around the workpiece are used to roll the contour of the transition from a central diameter in one portion of the workpiece to the central diameter in the adjacent portion by means of co-ordinated control of the radial advance of the rolling tools and the axial feed of the workpiece, and a mandrel head having an outer diameter which is adapted to the smallest inner diameter of the two portions is disposed underneath the rolling tools.

1 ) Method of transversely rolling stepped hollow shafts or cylindrical hollow parts from a pipe with rolling tools which can be advanced radially and are disposed in a planet-like manner around the workpiece, axial feed between the workpiece and rolling tools and a mandrel, wherein the rolling tools are used to roll the contour of the transition from a central diameter in one portion of the workpiece to the central diameter in the adjacent portion by means of co-ordinated control of the radial advance of the rolling tools and the axial feed, and a mandrel head having an outer diameter which is adapted to the smallest inner diameter of the two portions is disposed underneath the rolling tools. 
   
   
       2 ) Method as claimed in  claim 1 , wherein the rolling tools comprise a cylindrical smoothing shoulder and a conical forming shoulder. 
   
   
       3 ) Method as claimed in  claim 1 , wherein in addition to the clearance required for the axial mobility of the mandrel head in the workpiece, a flexing clearance of at least 0.1 mm is provided between the outer diameter of the mandrel head and the corresponding smallest inner diameter of the workpiece. 
   
   
       4 ) Method as claimed in  claim 1 , wherein the workpiece is externally supported against transverse forces at least one site by support rollers. 
   
   
       5 ) Method as claimed in  claim 1 , wherein the workpiece is turned when changing from one portion to the next. 
   
   
       6 ) Method as claimed in  claim 1 , wherein the rolling tools are turned when changing from one portion to the next. 
   
   
       7 ) Method as claimed in  claim 1 , wherein prior to rolling a portion the workpiece is heated in the region of the next forming portion. 
   
   
       8 ) Device for transversely rolling stepped hollow shafts or cylindrical hollow parts from a tube with rolling tools which can be radially advanced and are disposed in a planet-like manner around the workpiece, devices for producing an axial feed between the workpiece and the rolling tools and a mandrel, wherein the control of the radial advance of the rolling tools and the control of the axial feed between the rolling tools and the workpiece are coupled together by a program control and a mandrel head having the outer diameter which is adapted to the smallest inner diameter of the two portions is disposed approximately below the rolling tools. 
   
   
       9 ) Device as claimed in  claim 8 , wherein the rolling tools comprise a cylindrical smoothing shoulder and a conical forming shoulder. 
   
   
       10 ) Device as claimed in  claim 9 , wherein the free edge of the smoothing shoulder is rounded off with a radius r of 0.5 to 3 mm. 
   
   
       11 ) Device as claimed in  claim 8 , wherein the mandrel consists of a mandrel head and a mandrel shaft which is reduced in diameter with respect to the mandrel head. 
   
   
       12 ) Device as claimed in  claim 11 , wherein the mandrel head length corresponds approximately to the axial width of the rolling tools. 
   
   
       13 ) Device as claimed in  claim 11 , wherein the mandrel head is cylindrical. 
   
   
       14 ) Device as claimed in  claim 8 , wherein in addition to the clearance required for the axial mobility of the mandrel head in the workpiece, a flexing clearance of at least 0.1 mm is provided between the outer diameter of the mandrel head and the corresponding smallest inner diameter of the workpiece. 
   
   
       15 ) Device as claimed in  claim 8 , wherein the workpiece is mounted between support rollers which can be radially advanced. 
   
   
       16 ) Device as claimed in  claim 15 , wherein in each case three support rollers are disposed in one plane in a planet-like manner around the workpiece and these three support rollers are mounted in a stand. 
   
   
       17 ) Device as claimed in  claim 16 , wherein the stand is disposed in an axially displaceable manner in a guide ( 11 ) lying in parallel with the workpiece axis. 
   
   
       18 ) Device as claimed in  claim 17 , wherein at least one stand also travels at the axial speed of the workpiece part, to which it is allocated. 
   
   
       19 ) Device as claimed in  claim 18 , wherein the travelling stand is allocated an axial drive and the control thereof is connected to the program control. 
   
   
       20 ) Device as claimed in  claim 16 , wherein at least one stand is disposed in a stationary manner in the vicinity of the rolling tools. 
   
   
       21 ) Device as claimed in  claim 8 , wherein the rolling carriage ( 5 ) is axially displaceable.