Double row tapered roller bearings, including SR (two-out home every right circle combination, timkenSD (with a circular hole), SS (two-out every lap hasp loop combination), TDI (two-out double inner ring), TDO (double row Two-outer ring), TNA / TNASW / TNASWE (non-regulation two-out bearing / lubrication groove with TNA / file with the extension while TNA), TNASWH (thick-walled outer ring with TNA), TNASWHF (with the outer ring flange TNASWH), Uni -Pac ™ portfolio of bearings. Tapered roller bearings to bear the main radial-based track, combined axial loading. Bearings carrying capacity depends on the outer ring raceway’s point of view, the greater the perspective of the greater carrying capacity. Kind of Bearing a separation-bearing, according to the bearings in the roll-out is divided into several separate, two-out, and 4 tapered roller bearings. Single row tapered roller bearing clearance to be installed in the user to adjust; and double row tapered roller 4 Bearing clearance in the factory when the user based on the requirements given that users do not have to adjust. Tapered Roller Bearings are widely used in automotive, mill, mining, metallurgy, plastics machinery industry. That there are two kinds of roller bearings, it could be afford To a larger diameter containing mainly radial, axial joint load.