To provide a drawing method and apparatus for forming a boss part which has a diameter smaller than the outside diameter of a base stock and has a certain height.
The drawing method is provided in which a disk-like workpiece W is attached through a mandrel 4 on the distal end of a rotating spindle 2, the workpiece W is fixed with a chuck bar 3a which is rotated concentrically with the spindle 2 and drawing is performed by bringing a drawing roller into contact with the workpiece W. The drawing method is characterized in that the boss part is formed by: bending the circumferential part of the workpiece W with a drawing roller R1; performing dehiscing work by pressing a dehiscing roller R2 against the bent circumferential part; performing expanding work by pressing an expanding roller R3 against the dehisced part of the workpiece W which is dehisced with a dehiscing roller R2; and pressing an expanding roller R4 against the expanded part of the workpiece W which is expanded with the expanding roller R3.
COPYRIGHT: (C)2008,JPO&INPIT
MURATA SHIGEO
JPH1029029A | 1998-02-03 | |||
JPH01278919A | 1989-11-09 | |||
JPH0985370A | 1997-03-31 |