The selection criteria for bearings include the following aspects:

1. Bearing size: The best bearing type and size that fits the allowable space of the machine should be selected.

2. Bearing load: It is necessary to consider the load characteristics acting on the bearing, including radial load, axial load, etc. According to different load characteristics, select the appropriate bearing type and size.

3. Allowable speed: Different types of bearings have different allowable speeds, and it is necessary to select the appropriate bearing type based on the operating speed of the machine.

4. Bearing tolerance: Select suitable bearing tolerances for equipment that requires high-tolerance shaft runout or high-speed operation.

5. Cage structure: Select a suitable cage structure based on factors such as the operating speed, vibration, noise, and lubrication method of the bearing.

6. Lubrication selection: Select the appropriate lubrication method and lubricant based on the working environment, speed, load, and other factors of the bearing.

7. Space size: Consider the space size in the machine and choose the appropriate bearing type and size.

8. Safety factor: Select bearings with sufficient safety factors based on factors such as the load size and speed required to be withstood.

9.Friction torque: Considering the influence of bearing friction torque, select the appropriate bearing type and size.

10. Other factors: It is also necessary to consider the environmental and operating temperatures of the bearing, the clearance, and the allowable deflection of the rings.

In summary, when selecting bearings, it is necessary to consider the above criteria comprehensively based on the actual working conditions and usage requirements, and choose the appropriate bearing type and size. At the same time, it is also important to pay attention to proper installation and maintenance methods to ensure the normal use and longevity of the bearings.