Application of high speed angular contact ball bearings


The high-speed spindle system of the CNC gold-cutting machine, as the name suggests, has a high slew speed, but there is no strict limit. For the machining center and CNC milling machine represented by high-speed cutting machine, it generally refers to the spindle system with the maximum speed ≥ 10,000r/min, and correspondingly has a high angular addition (decrease) speed to realize the instantaneous speed increase and start of the spindle. stop. In order to meet the ever-increasing requirements of the manufacturing industry for machine tool machining accuracy, the high-speed cutting spindle should also have a high degree of rotation accuracy. Usually, the radial runout of the spindle is required to be less than 1 or 2 μm, and the axial yaw is less than 1 μm. In addition, the spindle must have sufficient static and dynamic stiffness to withstand certain cutting loads and maintain high rotational accuracy.

The traditional spindle system includes intermediate transmission links such as belts and gears. Not only is the moment of inertia large, it is difficult to achieve high angular addition (decrease) speed, and it is difficult to solve the vibration and noise of the intermediate transmission link at high speed. Therefore, the current high-speed spindle system is mostly an electric spindle unit that "binds the motor" to the main shaft and shortens the transmission chain to zero. The structure basically places the main motor between the front and rear bearings of the main shaft. Such an electric spindle has a short axial dimension, a compact structure, a high spindle rigidity, and a large output. This type of structure is used by GMN's electric spindles for machining centers and CNC milling machines. Its bearings are precision angular contact ball bearings suitable for high speed operation (generally equivalent to international standards P2 and P4). All key parts must be precision machined. And precision assembly, while cooling the stator and front and rear Tilting pad journal bearing of the main motor with constant temperature cooling water (GMN 23 ± 0.7 ° C or even ± 0.3 ° C). GMN has more than 20 types of electric spindles for machining centers and CNC milling machines. The maximum speed ranges from 8000r/min to 60,000r/min, the power ranges from 5.5kW to 76kW, and the torque ranges from 0.9Nm to 306Nm.