| 摘要 |
PROBLEM TO BE SOLVED: To suppress the lowering of degree of adhesion between an inner ring member and an inner shaft by forming a caulking part.SOLUTION: A hub unit includes an inner shaft having a small diameter part 23 on a part of axial direction and an inner ring member fitted to an outer circumferential surface 23c of the small diameter part 23 and fixes the inner ring member to the inner shaft by means of a caulking part 24 which plastically deforms an axially directional end part of the inner shaft to the axially directional outer side. Therein, on either one side of the outer circumferential surface 23c of the small diameter part 23 and an inner circumferential surface of the inner ring member fitted to the outer circumferential surface 23c, at least a swollen surface 23c1 which is convexly curved toward the other side of the outer circumferential surface of the small diameter part 23 and the inner circumferential surface of the inner ring member and is swollen in a state before forming the caulking part 24, a cylindrical cylinder surface 23c2 which is arranged on an axially directional both sides of the swollen surface 23c1 and has a constant radius while setting an axial center of the hub unit as a center and a connection surface 23c3 which is arranged between the swollen surface 23c1 and the cylinder surface 23c2, is convexly curved and smoothly connects the swollen surface 23c1 and the cylinder surface 23c2 are provided.SELECTED DRAWING: Figure 4 |
