Tapered roller bearings have tapered raceways on the inner and outer rings, and tapered rollers are fitted between the raceways. If the tapered surface is extended, eventually converges on the axis of the bearing on a point. The tapered roller bearing is mainly used to bear radial load mainly radial, axial combined load. The axial bearing capacity is determined by the contact angle, the larger, the greater the axial bearing capacity. Tapered roller bearings are separated bearings, the inner ring with rollers and cage constitutes the inner assembly, which can be installed separately from the outer ring. This kind of bearing can limit the shaft or shell side of the axial displacement and does not allow the shaft to relative to the shell hole having a tilt. The radial load will produce additional axial force, therefore, generally in the bearing two support, the bearing outer ring and inner ring with each end face should be installed relatively. The main use of this type of bearings: are automobile front wheel, rear wheel, transmission, differential, pinion shaft, machine tool spindle, construction machinery, large agricultural machinery, railroad vehicle gear reduction device, rolling mill neck small reduction device.