BEARING DEVICE FOR WHEEL AND MANUFACTURING METHOD THEREFOR

Provided is a bearing device (1) for a wheel, including: an outer member (2) having double-row outer raceway surfaces (7, 7) formed on an inner circumference thereof; an inner member (11) including: a hub wheel (3) having a wheel mounting flange (8) formed thereon; and at least one inner race (4) fitted to a small-diameter step portion (10) formed on an outer circumference of the hub wheel (3), the inner member (11) having double-row inner raceway surfaces (9, 9) formed thereon so as to be opposed to the double-row outer raceway surfaces (7, 7); and a plurality of rolling elements (5, 5) assembled into spaces between the double-row outer raceway surfaces (7, 7) and the double-row inner raceway surfaces (9, 9), the at least one inner race (4) being fixed in an axial direction thereof by a staked portion (17) formed by plastically deforming an end portion (26) of the small-diameter step portion (10) of the hub wheel (3) radially outward, the staked portion (17) having a face spline (18) formed on an end surface thereof by plastic working, in which the following relationship is satisfied: S/M¤±×ß, where M represents a mean diameter of an outer diameter (B) and an inner diameter (C) of the end portion (26) of the small-diameter step portion (10) of the hub wheel (3) before the staked portion (17) is formed, S represents an outer diameter of the face spline (18), ± represents a value indicating ductile elongation of a material for the hub wheel (3) in terms of proportion, and ß represents a correction coefficient depending on a type of process.