Machine tool bearings mainly include three parts: spindle, ball screw and general transmission shaft. As the basic supporting parts of machine tools, the performance of spindle bearings directly affects the machine tool's speed, rotation accuracy, rigidity, anti-vibration cutting performance, noise, temperature rise and thermal deformation, and further affects the precision and surface quality of machined parts. Therefore, high-performance machine tools must be equipped with high-performance bearings. Spindle bearings for machine tools usually include deep groove ball bearings, angular contact ball bearings, cylindrical roller bearings, double-direction thrust angular contact ball bearings, tapered roller bearings and thrust bearings. Bearings for ball screw support include thrust angular contact ball bearings. Bearings for general transmission shafts include ball bearings, cylindrical roller bearings, tapered roller bearings.