WHEEL BEARING, STEEL BALL THEREIN AND MANUFACTURING METHOD OF THE STEEL BALL

摘要

A wheel bearing, a steel ball included in the wheel bearing, and a manufacturing method thereof are disclosed. The wheel bearing, the steel ball included in the wheel bearing, and the manufacturing method thereof according to the embodiment of the present invention includes a step (a) of cold-forging the steel ball included in the bearing and heat treating the steel ball after polishing the surface of the steel ball as a preprocessing step; a step (b) of primarily grinding the surface of the steel ball; a step (c) of tumbling the surface of the steel ball; a step (d) of secondarily grinding the surface of the steel ball; and a step (e) of primarily and secondarily wrapping the surface of the steel ball and washing the steel ball. [Reference numerals] (S1) Step of cold-forging a steel ball;(S10) Step of examining the steel ball;(S11) Step of packing the steel ball;(S2) Step of grinding the surface of a raw steel ball;(S3) Step of heat treating the steel ball;(S4) Step of primarily grinding the surface of the steel ball;(S5) Step of tumbling the surface of the steel ball;(S6) Step of secondarily grinding the surface of the steel ball;(S7) Step of primarily wrapping the surface of the steel ball;(S8) Step of secondarily wrapping the surface of the steel ball;(S9) Step of washing the steel ball