Roller bearing is a type of rolling bearing and is one of the most widely used components in modern machinery. Rolling bearings are composed of inner ring, outer ring, cage and rolling elements. Roller bearings are now mostly standardized. They have the advantages of small torque required for starting, high rotation, and convenient selection. The materials used in roller bearings are divided into bearing steel Gcr15, carbon steel, stainless steel, plastic, ceramics, etc. Roller bearings are divided into spherical roller bearings, thrust spherical roller bearings, tapered roller and cylindrical roller bearings, etc.