The inner and outer rings of tapered roller bearings have tapered raceway. The tapered rollers are mounted between raceways. Tapered roller bearings can bear combined radial and axial load. These bearings are mainly used on automobile wheels, variable speed devices, differential mechanisms, pinion shafts, machine tools, construction machines, large size agricultural machines, gear deceleration devices for railway vehicles, and small deceleration devices for mill roll necks.