The spindle of machine tool refers to the axis that drives the workpiece on the machine tool. The CNC machine tool is red in the working process. It is clamped by the spindle and directly participates in the surface forming movement. The spindle is the terminal executive key for the CNC machine tool to realize cutting processing. Its rotation accuracy plays a very important role in the accuracy of the machine tool.

　　The structure of the spindle bearing of CNC machine tools is basically limited to four structural types: angular contact ball bearing, cylindrical roller bearing, bidirectional thrust angular contact ball bearing and tapered roller bearing.

　　Because of its small density, high elastic modulus, small coefficient of thermal expansion, wear resistance and high temperature resistance, ceramic materials have become the ideal materials for manufacturing high-speed bearings. Ceramic bearings have also been more widely used. Based on the difficult machining properties of ceramic materials, ceramic bearings are mostly rolling elements, which are hybrid ceramic ball bearings with ceramic and inner and outer rings still made of chromium steel.

　　Generally speaking, the CNC machine tool spindle bearing and ball screw bearing mentioned by us refer to the spindle bearing and screw bearing with the accuracy of P5 or above.

　　CNC machine tools are used for rolling bearings on general transmission bearings, and the selection is the same as that of ordinary mechanical transmission bearings. As long as the strength and life requirements are met, and the speed does not exceed the specified speed.