The tapered roller bearing belongs to the separation type bearing. The inner and outer rings of the bearing have tapered raceways. This kind of bearing can be divided into single row, double row and four row tapered roller bearings according to the number of rows of rollers. Single row tapered roller bearing can bear radial load and single direction axial load. When the bearing bears the radial load, it will produce an axial component force, so it needs another bearing that can bear the axial force in the opposite direction to balance.