Ball screw is used to transmit linear motion. It has the characteristics of high accuracy, high axial rigidity, low torque and long life. It is widely used in precision machinery and equipment, and it is an indispensable accessory for precision measurement tools of CNC machine tools.
The accuracy and mounting rigidity of ceramic ball bearings for ball screws are important factors in ensuring the high accuracy and high axial rigidity of ball screws. The bearing structure adopted by ball screws at home and abroad is usually high-precision angular contact ball bearings. This type of bearings has very strict requirements and must meet the ISO international standard P4 or higher. In order to improve the axial bearing capacity of the bearing, a large 60 ° contact is usually used Angle bearing. In order to achieve great axial rigidity, the most common is to use a group installation.
With the expansion of the production scale of CNC machine tools and the increase in the social ownership of CNC machine tools, the social demand for ball screws has also increased. According to the development forecast of the machine tool industry, the demand for ball screws in China in 1995 was 120,000 pairs, in 2000 it was 160,000 pairs, and in 2005 it is expected to be 200,000 pairs. Each pair of ball screw supporting precision bearings is calculated on the basis of 4 sets. In 2005, the domestic demand for precision bearings for ball screws was 800,000 sets, and ceramic ball bearings were used at a rate of 20%. The annual demand for ceramic ball bearings was 160,000 sets.
Therefore, a total of 1.47 million sets of precision bearings and ceramic ball bearings are required for CNC machine tool spindles, grinder electric spindles, other metal processing machine spindles and ball screws, of which ceramic ball bearings are 425,000 sets.