US Patent 7832942 Wheel bearing apparatus

A vehicle wheel bearing apparatus has an outer member and an inner member. The inner member has a wheel hub and at least one inner ring fit onto a cylindrical portion of the wheel hub or an outer raceway surface of a constant velocity universal joint. Double row rolling element groups are freely rollably contained between said inner and outer raceway surfaces of the inner member and the outer member. A pitch circle diameter of the ball element group near to the wheel mounting flange is larger than that of the double row ball group away from the wheel mounting flange. A maximum diameter of the outer raceway surface of the smaller diameter side of the double row outer raceway surfaces of the outer member is substantially the same as an inner diameter of a shoulder portion of the outer diameter side. The size of each rolling element of the group near to the wheel mounting flange is different from that of each rolling element of the group away from the wheel mounting flange. The number of rolling elements of the group near to the wheel mounting flange is larger than the number of rolling elements of the group away from the wheel mounting flange.