Tapered roller bearing belongs to the separate type bearing, and the inner and outer rings of the bearing have tapered raceway. The bearing is divided into single row, double row and four row tapered roller bearing according to the number of columns installed. Single row tapered roller bearings can bear radial load and single direction axial load. When bearing is under radial load, one axial force will be generated, so when another bearing can bear the axial force in the opposite direction is needed to balance.