As the basis for machine tool spindle bearing parts, its performance directly affects the speed of the machine, rotary precision, rigidity, resistance to cutting chatter vibration, noise, temperature and thermal deformation, thereby affecting the accuracy, surface quality of machined parts and the like. Therefore, a high-performance machine must be equipped with a high-performance bearings.
Accuracy of rolling bearings is generally divided into P0, P6, P5, P4 and P2 five grades, for the accuracy of precision machine tool spindle bearings should P5 level and above, and for CNC machine tools, machining centers and other high-speed, high-precision machine tools spindle bearing, you need to choose P4 and above-grade super-precision bearings.
Machine tool spindle bearings usually include deep groove ball bearings, angular contact ball bearings, cylindrical roller bearings, angular contact thrust ball bearings, tapered roller bearings and thrust bearing structure of six types.
With the rapid development of numerical control technology, "complex, high-speed, intelligent, sophisticated, environmental protection" has become a major trend in today's machine tool industry technology development. Among them, the high-speed processing can improve the machining efficiency, shorten the processing cycle of the workpiece. This requires the spindle and its associated components to adapt to the needs of high-speed processing. Currently, the CNC machine tool spindle bearings substantially limited in angular contact ball bearings, cylindrical roller bearings, angular contact thrust ball bearings and tapered roller bearings and other types of four structures.
With the CNC machine tool spindle to speed the development of ceramic materials (mainly engineering ceramics Si3N4) due to a low density, high elastic modulus, thermal expansion coefficient, wear resistance, high temperature resistance, corrosion resistance and other excellent performance, thus becoming manufactures high-speed ideal material for precision bearings. Ceramic bearings are more widely used, in view of the difficult process of ceramic materials, precision ceramic bearing rolling elements are mostly ceramics, chrome steel inner and outer rings still manufactured hybrid ceramic ball bearings.
As a precision ball screw, efficient and sensitive transmission components, should be used in addition to high-precision screw, nut and ball, we must also pay attention to the choice of the axial stiffness, friction torque, high running accuracy of the bearing. Ball bearing it used two-way thrust angular contact ball bearings, tapered roller bearings, needle roller and thrust roller bearings, deep groove ball bearings and thrust ball bearings. Currently, ball bearing is the most used contact angle of 60 ° Single row angular contact ball bearings and precision level P4 and above is also based on the main level.
