Tapered  roller  bearings

　　　Tapered roller bearing consists of an inner assembly and a detached outer race. The inner assembly includes a inner race of tapered raceway, tapered roller and holder. Each vertex of the raceway face of inner race, the raceway face of outer race and the rolling face of roller is designed to go across a point of bearing central line. The modified line contact between the roller and the raceway can reduce stress centralization. Tapered roller bearing is used mainly to bear combined radial and axial loads with radial load as the dominating element and applied to bear heavy and impact loads. Its load-bearing capacity depends on the contact angle α，i.e. the angle of outer  raceway. The bigger the contact angle, the larger the axial load-bearing capacity. The dimensions of axial play are of great importance to the normal operation of bearings. Too small an axial play will cause a higher temperature rise whereas a larger play will result in possible bearing damage. Special attention shall be paid to the axial play of bearing duiring mounting. Mounting with a shrink range is allowed so as to increase the rigidity of bearings.
　　　Single row tapered roller bearing can bear radial load and unidirectional axial load. If the bearing bears only radial force, the axial component force resulted from the inside of bearing must be balanced. Therefore, single row tapered roller bearings are generally mounted and used in pair.
　　　Double-rows tapered roller bearing can bear radial load and bi-directional axial movement of bearing housing within the range of bearing axial play. The performance of four-rows taperded roller bearing is almost similar to that of double-rows tapered roller bearing. It can bear larger radial load but has lower limint revolution. The bearings are mainly used in heavy machinery,especially widely used in steel rolling mills.