Tapered roller bearings are separated bearings, and the inner and outer rings of the bearings have tapered raceways. This kind of bearing is divided into single row, double row and four row tapered roller bearing and other different structural types according to the number of rows of rollers installed. Single row tapered roller bearing can bear radial load and single direction axial load. When the bearing bears radial load, an axial component will be generated, so when another bearing that can bear the axial force in the opposite direction is needed to balance.