Method of manufacturing shaft member for wheel rolling bearing device

Abstract

According to a method of manufacturing a flanged shaft member having a plurality of flanges used to fasten the shaft member to a wheel, when the flanges are formed on a part between a shaft portion and a fitting shaft portion through lateral extrusion while a forged recess is formed at a center of an end surface of the fitting shaft portion with the use of a forging die apparatus for cold forging, each flange is formed so as to be curved in a direction opposite to a direction, in which the flange warps due to springback caused after the lateral extrusion, by an amount corresponding to an amount of warpage due to the springback.

1 . A method of manufacturing a shaft member for a wheel rolling bearing device, the shaft member having a shaft portion, a fitting shaft portion formed on one end side of the shaft portion and a flange located between the shaft portion and the fitting shaft portion so as to extend radially outward, the method comprising:
 forming the flange on a part between the shaft portion and the fitting shaft portion through lateral extrusion while forming a forged recess at a center of an end surface of the fitting shaft portion with use of a forging die apparatus for cold forging,   wherein the flange is formed so as to be deformed in a direction opposite to a direction, in which the flange warps due to springback caused after the lateral extrusion, by an amount corresponding to an amount of warpage due to the springback.