BEARING DEVICE FOR WHEEL

摘要

PROBLEM TO BE SOLVED: To provide a bearing device for a wheel, which secures the strength of its caulking part and on which the most proper shape of the caulking part is set in accordance with bearing size. SOLUTION: In the wheel bearing device wherein an inner ring 3 is press-fitted to a small-diameter step 2b of a hub wheel 2 and the inner ring 3 is fixed by a caulking part 2c formed by plastically deforming the end toward an outer side in a radial direction, the end of the small-diameter step 2b is formed in a hollow cylindrical part 12 before being caulked. Based on the great end surface 3b of the inner ring 3, when an axial size up to the bottom surface 12a of the cylindrical part 12 is expressed as L1, the axial size up to an intersection P of the line of action S of a ball 6 at the inner side and the small-diameter step 2b as L2, the cross section of the caulking part 2c as A (mm2), a basic static rating radial load of a train of balls 6 on the inner side as C0r (kN), and the number of balls 6 as Zi, the shape and dimensions of the caulking part 2c are set so as to satisfy both reference expressions: L2>L1, and 0.672Amin≥C0r×Zi×tanθ+80. COPYRIGHT: (C)2010,JPO&INPIT