BEARING RING MEMBER FOR ROLLER BEARING UNIT, ROLLER BEARING UNIT, AND MANUFACTURING METHOD OF BEARING RING MEMBER FOR ROLLER BEARING UNIT

摘要

PROBLEM TO BE SOLVED: To provide a structure and a manufacturing method capable of obtaining a bearing ring member for a roller bearing unit and the roller bearing unit at low cost.;SOLUTION: A hub body 13a having a fitting flange 15 on a part of an outer circumferential surface is formed by performing the side extrusion on a columnar material 25. Before the side extrusion, a portion forming the fitting flange 15 is ironed at a part of the axial direction of the material, and this portion is work-hardened to form an intermediate material. Thereafter, the intermediate material is subjected to the side extrusion to form the fitting flange 15. The base portion of the fitting flange 15 is constituted of the work-hardened portion. Even by reducing the thickness of the fitting flange 15, the required strength can be ensured.;COPYRIGHT: (C)2007,JPO&INPIT