| 摘要 |
A bearing apparatus for wheel (1) with ensured high durability by including a part with improved fatigue strength in a non-hardened portion includes an outer member (10), an inner member (20), and a roller (50). The inner member (20) includes a hub ring (30) made of steel and having a wheel attachment flange (31) formed. The hub ring (30) has a hardened portion (39) hardened to attain at least 50 HRC as a result of quench hardening and a non-hardened portion (33) which is a portion other than the hardened portion (39). Compressive stress in a range from at least 50MPa to at most 500MPa remains in the surface of the non-hardened portion (33). |
