Application of ceramic ball bearings in high speed spindle unit

   Ultra-high-speed cutting is high quality, efficient and characterized by advanced manufacturing technology, which can bring high-speed cutting mechanism, high-speed spindle unit, high acceleration and deceleration linear feed motor development, high-performance control systems and other related cell technology. Core support high-speed spindle unit is high-speed spindle bearings. Ceramic bearings for its resistance to high speed, light weight, long life, excellent performance, high-speed spindle unit in machine tools are widely used.
   A high-speed spindle unit and the spindle slewing bearing manufacturer High-speed spindle unit is one of the key technology to achieve high-speed processing, but also a key component of high-speed machine tools. The core of the high-speed spindle unit is high-speed precision bearings, its performance directly affects the performance of work spindle unit. With increasing speed, the bearing temperature, vibration and noise increase, decrease in the life. Therefore, increasing the spindle speed on the premise that developed a superior performance, high-speed spindle bearings. Currently, high-speed spindle unit, supporting mainly uses magnetic double direction thrust ball bearing spindle, liquid hybrid bearing, ceramic ball bearings in three forms. Magnetic Bearings and good high-speed performance, high precision, easy to implement diagnostics and online monitoring. But practice shows that the bearing due to electromagnetic measurement and control system is too complex and has not been widely used. Liquid hybrid bearing combines the advantages of hydrostatic bearings and hydrodynamic bearings, but this bearing must be specifically designed according to the specific machine, a separate production,the low degree of standardization, maintenance is also difficult.
   Currently, the most widely used high-speed spindle bearings or hybrid ceramic ball bearings, namely the use of the rolling elements or hot isostatic pressing Si3N4 ceramic ball bearing rings remains rims. Such a high degree of standardization of the bearings, low price, small changes to the machine for easy maintenance, especially for high-speed operation of occasions. It d · n has exceeded the value 2.7 × 106. To increase bearing life, increase the wear resistance of the raceway, the raceway of the coating treatment or other surface treatment.
   2 Experimental Research
   Test conditions
   The ceramic ball bearings used in the test parameters as shown in Table 1. The ceramic ball material HIPSN (hot isostatic pressing Si3N4), the accuracy level is G3 level, balls and rings when assembling the required value of the fine matching. The bearings are "dense beads beads" structure, and use the thin outer cage. In the tests with the ceramic bearing ball flange bearing

 steel having the same structural parameters.
   Spindle tests used are two models, namely A-type and B-type. Structure schematically shown in Figure 1, the bearing installation in the form of DBB. Table 2 is the main performance parameters of the two spindle.
Table 1 Test parameters with ceramic ball bearing Model Dimensions (mm) ball diameter (mm) contact angle of the original number of balls ceramic ball material cage material ferrule material
   B7007CY35 × 62 × 147.1441615HIPSN resin GCr15
   The main performance parameters in Table 2 spindle
Model limit speed (r / min) spindle diameter (mm) output power (kW) Lubrication
A mist type 30000354.5
B-type 24000354.5 fat
    A high-speed spindle unit structure diagram in Fig.