Tapered roller bearings have tapered inner and outer ring raceways and tapered rollers and cage which are applied in combination of radial and axial (thrust) loads. The non-separable inner ring and roller assembly is called the "cone", and the outer ring is called the "cup". Internal clearance is established during mounting by the axial position of the cone relative to the cup. The bearing could be divided into single row, double-row and four-row taper roller bearings with different structures according to the columns of their rollers. 
Tapered roller bearings are used in numerous applications and are capable of high loads and speeds. The predominant use is in any wheel application, where the tapered roller bearings are normally arranged in back to back pairs where they support axial and radial loads in both directions. Tapered roller bearings are available in a wide array of both inch and metric sizes. Four- row taper roller bearings are used in heavy machine such as cold mill and hot mill etc.