| 摘要 |
A wheel drive unit is provided to comprise a bearing unit 3e for wheel drive which is light in weight and low in cost. The components constituting the bearing unit 3e for wheel drive have optimum properties to secure the durability thereof.Of the components constituting the bearing unit 3e for wheel drive, the portions indicated by a diagonal grid hatching are quench-hardened with the other portions being not quench-hardened and left as they are, whereby the rolling fatigue life and wear-resistance of the components are improved and cracking is prevented. |
