Spherical roller bearings are divided into symmetrical spherical roller bearings and asymmetrical spherical roller bearings according to the shape of the roller section. Asymmetrical spherical roller bearings are early products and mainly serve the maintenance of the main motor. Symmetric spherical roller bearings are rarely used in the new design of the main motor. The internal structure has been comprehensively improved and optimized. Compared to the early production of spherical roller bearings, they can withstand greater axial load.