Arrangement form of CNC machine tool spindle bearings

At present, there are three main configuration forms of CNC machine tool spindle bearings.

1. The front support adopts a combination of double-row cylindrical roller bearings and double-row 60° angular contact ball bearings, and the rear support adopts paired angular contact ball bearings (as shown in Figure 1). This configuration greatly improves the comprehensive rigidity of the spindle and can meet the requirements of strong cutting, so it is widely used in the spindles of various CNC machine tools.

2) High-precision double-row angular contact ball bearings are used (as shown in Figure 2). Angular contact ball bearings have good high-speed performance, and the maximum speed of the spindle can reach 4000r/min, but its load capacity is small, so it is suitable for high-speed, light-load and precision CNC machine tool spindles. In the main shaft of the machining center, in order to improve the load-carrying capacity, sometimes the front support combined with 3 or 4 angular contact ball bearings is used, and the spacer is used to achieve preload.

3) Double-row and single-row tapered bearings are used (as shown in Figure 3). This kind of bearing has high radial and axial rigidity, can bear heavy loads, especially strong dynamic loads, and has good installation and adjustment performance. However, this bearing configuration limits the maximum speed and precision of the spindle, so it is suitable for medium-precision, low-speed and heavy-duty CNC machine tool spindles.