Forging device and forging method

Abstract

In a forging device including a rotating table and a shaping roller, which forging device forges a workpiece such that an outer peripheral surface of the shaping roller is pressed against an end surface of the workpiece in a central-axis direction of the workpiece while the workpiece is rotated by the rotating table, the shaping roller is placed apart from a rotation axis, and a position of that end of the outer peripheral surface of the shaping roller which is opposite to a rotation-axis side in a central-axis direction of the shaping roller is placed at an outer side in a radial direction of the workpiece relative to a position of an outer peripheral surface of the workpiece that has been forged.

1 . A forging device comprising:
 a rotating table that rotates around a rotation axis, and   a cylindrical shaping roller, wherein   the forging device forges a cylindrical workpiece such that an outer peripheral surface of the shaping roller is pressed against an end surface of the workpiece in a central-axis direction of the workpiece while the workpiece is rotated by the rotating table around a central axis of the workpiece,   the shaping roller is placed apart from the rotation axis; and   a position of that end of the outer peripheral surface of the shaping roller which is opposite to a rotation-axis side in a central-axis direction of the shaping roller is placed at an outer side in a radial direction of the workpiece relative to a position of an outer peripheral surface of the workpiece that has been forged.   
     
     
         2 . The forging device according to  claim 1 , further comprising:
 a cylindrical mandrel, wherein:   a central axis of the mandrel accords with the rotation axis;   the shaping roller has an inner end surface placed at the rotation-axis side in the central-axis direction of the shaping roller; and   a distance between the central axis of the mandrel and the inner end surface is larger than a radius of the mandrel but smaller than a radius of the workpiece.   
     
     
         3 . The forging device according to  claim 1 ,
 wherein two shaping rollers are provided in the forging device.   
     
     
         4 . The forging device according to  claim 1 , wherein:
 a central axis of the shaping roller is generally perpendicular to the rotation axis.   
     
     
         5 . A forging method for forging a cylindrical workpiece, by use of a rotating table that rotates around a rotation axis, and a cylindrical shaping roller comprising:
 rotating the workpiece around a central-axis direction of the workpiece by rotating the table,   pressing an outer peripheral surface of the shaping roller against an end surface of the workpiece in a central-axis direction of the workpiece, wherein   the shaping roller is placed apart from the rotation axis; and   a position of that end of the outer peripheral surface of the shaping roller which is opposite to a rotation-axis side in a central-axis direction of the shaping roller is placed at an outer side in a radial direction of the workpiece relative to a position of an outer peripheral surface of the workpiece that has been forged.   
     
     
         6 . The forging method according to  claim 5 , wherein:
 a cylindrical mandrel is used;   a central axis of the mandrel accords with the rotation axis;   the shaping roller has an inner end surface placed at the rotation-axis side in the central-axis direction of the shaping roller; and   a distance between the central axis of the mandrel and the inner end surface is larger than a radius of the mandrel but smaller than a radius of the workpiece.   
     
     
         7 . The forging method according to  claim 5 , wherein:
 two shaping rollers are used.   
     
     
         8 . The forging method according to  claim 5 , wherein:
 a central axis of the shaping roller is generally perpendicular to the rotation axis.