Tapered roller bearing mainly bears radial and axial combined load. The bearing capacity depends on the raceway angle of the outer ring, and the larger the angle is, the greater the bearing capacity is. This kind of bearing belongs to separate type bearing, which is divided into single row, double row and four row tapered roller bearings according to the number of rows of rolling elements in the bearing. The clearance of single row tapered roller bearing needs to be adjusted by the user during installation; the clearance of double row and four row tapered roller bearing has been given according to the user's requirements when the product is delivered from the factory, and does not need to be adjusted by the user.