A rolling-element bearing, also known as a rolling bearing, is a bearing which carries a load by placing rolling elements (such as balls or rollers) between two bearing rings called races. The relative motion of the races causes the rolling elements to roll with very little rolling resistance and with little sliding.
The use of rolling bearings on machine tools is mainly used in the following three parts: spindle, ball screw, and general drive shaft.
As the basic accessory of the machine tool, the spindle bearing directly affects the speed, rotation accuracy, rigidity, anti-shake vibration cutting performance, noise, temperature rise and thermal deformation of the machine tool, which affects the precision and surface quality of the machined parts. Therefore, high-performance machines must be equipped with high-performance bearings.
The accuracy of rolling bearings is generally divided into five grades: P0, P6, P5, P4 and P2. The accuracy of bearings used on precision machine tool spindles should be P5 and above, and for high-speed, high-precision machine tools such as CNC machine tools and machining centers. For the spindle support, P4 and above super precision bearings are required.
Spindle bearings for machine tools usually include six types of construction: deep groove ball bearings, angular contact ball bearings, cylindrical roller bearings, two-way thrust angular contact ball bearings, tapered roller bearings, and thrust bearings.
With the rapid development of numerical control technology, “composite, high speed, intelligent, precise, environmental protection” has become the main trend of the development of today’s machine tool industry technology. Among them, high-speed machining can effectively improve the machining efficiency of the machine tool and shorten the machining cycle of the workpiece. This requires the machine tool spindle and its related components to meet the needs of high-speed machining. At present, CNC machine tool spindle bearings are basically limited to four kinds of structural types: angular contact ball bearings, cylindrical roller bearings, two-way thrust angular contact ball bearings and tapered roller bearings.