| 摘要 |
PROBLEM TO BE SOLVED: To provide a rolling bearing unit for wheel support that prevents an impression from occurring on an outer ring raceway surface by a load (moment load or impact load) applied to the outer ring raceway surface, and is excellent in durability.SOLUTION: In the inner peripheral surface of an outer ring 2a, from an axial outside outer ring raceway surface 5a portion to an axial inside outer ring raceway surface 5b portion, a heat treatment hardening layer 20 is formed in the whole circumference by induction hardening. The treatment hardening layer 20 comprises an outside hardening layer 21, an inside hardening layer 22, and an intermediate hardening layer 23. A thickness dimension T1 of the large diameter side portion of each of the outside and inside hardening layers 21, 22 is larger than a thickness dimension T2 of the small diameter side portion of each of the outside and inside hardening layers 21, 22 (T1>T2). |
