Patent ID: 7832941

Claim:
A vehicle wheel bearing apparatus comprises: an outer member formed with double row outer raceway surfaces on its inner circumferential surface; inner member formed with an inner raceway surface on its outer circumferential surface, said inner raceway surface arranged opposite to the double row outer raceway surfaces; a rounded counter portion surface is formed on each raceway, each raceway surface and counter portion surfaces are ground simultaneously, at least one inner raceway surface counter portion formed near the bottom of the inner raceway surface has a desired width and including a smaller diameter portion adjacent a tapered stepped portion; double row ball groups are freely rollably contained between the outer raceway surfaces and inner raceway surface of the inner member and the outer member; a pitch circle diameter of an outer side ball group is larger than a pitch circle diameter of an inner side ball group; and each corner portions of the outer circumferential surfaces of the inner members is rounded as a smooth circular arc.