To improve the fatigue strength of a neck of a flange for fitting to a wheel without increasing high frequency hardening parts, and to facilitate the lightening of a bearing unit with the flange by making the thickness of the flange for fitting to the wheel thin.
A hub wheel 2 of the bearing unit with flange is made of carbon steel with the carbon content of more than 0.45 weight % but less than 0.65 weight %. The hub wheel 2 is made so that the area rate of the pro-eutectoid ferrite per unit area (10mm2) at least on the outside neck part 14 of the flange 6 for fitting to the wheel is 3 to 15 %, the maximum length of the pro-eutectoid ferrite is made to be less than 200μm, and it makes less than five pieces of pro-eutectoid ferrite with the length of more than 180μm.
| JP2005517580 | Wheel hub assembly |
| JP2005212713 | BEARING DEVICE FOR WHEEL |
MIYAMOTO YUJI
OKITA SHIGERU
Yoshiaki Naito
Cui Shu Tetsu