To provide a manufacturing method for reducing radial force applied to a hub 2 when plastically deforming a cylindrical portion 10 at its front end outward in the radial direction to form a caulked portion.
To form the caulked portion, a force plunger 15a is pushed at its lower end face against the whole periphery of the front end of the cylindrical portion 10 in the axial direction. Thus, the cylindrical portion 10 is plastically deformed at its front end a preset amount outward to the radial direction (preliminary molding). Then, the force plunger 15a being rockingly turned is pushed at its lower end face against the front end of the cylindrical portion 10. Thus, the cylindrical portion 10 is further plastically deformed at its front end outward to the radial direction to form the caulked portion (main molding). In the preliminary molding, no radial force is substantially applied to the hub 2, while, in the main molding, smaller radial force is applied to the hub 2.
YASUMURA SHOKO
Nakai Shun
Kinzo Koyama