BEARING DEVICE FOR WHEEL

摘要

A bearing device for a wheel, where a bearing has sufficient durability and whose rigidity is further increased with an increase in the weight of the device suppressed. The bearing device is composed of a double-row tapered roller bearing. A large flange formed on the large diameter side of an inner rolling surface (10a) of a hub ring (10) is formed as a flange ring (16) separately from the hub ring (10) and is fitted to the outer periphery of the hub ring (10) adjacent to a wheel mounting flange (9). The pitch circle diameter PCDo of a tapered roller (5) row on the outer side is larger than the pitch circle diameter PCDi of a tapered roller (6) row on the inner side. Also, the diameter of the tapered rollers (5) on the outer side is smaller than the diameter of the tapered rollers (6) on the inner side. As a result, the number of the tapered rollers (5) on the outer side is more than that of the tapered rollers (6) on the inner side, and this provides the bearing with enhanced durability and increases rigidity of the bearing device while suppressing an increase in its weight.