9 main factors you must consider when selecting bearings

Different types of bearings have different features or properties for different designs. Due to the variability and complexity of the application as well as the specific installation position of the bearing, there is no fixed mode for the selection of bearing type. When selecting the bearing type to meet the specific requirement of a certain equipment, it is recommended to consider the following 9 main factors.

 

1.Space Allowance

In mechanical design, the size of the shaft is generally determined first, and then the bearing is selected according to the size of the shaft. Usually, ball bearings are used for small shafts; cylindrical roller bearings, spherical roller bearings, and tapered roller bearings (sometimes ball bearings are also optional) for large shafts. If the radial space of the bearing installation part is limited, bearings with smaller radial section height should be used. Such as needle roller bearings, some series of deep groove ball bearings, angular contact ball bearings, cylindrical or spherical roller bearings and thin section ball bearings. If the axial space of the bearing installation part is limited, bearings with a smaller width shall be adopted then. 


 

2.Bearing load

Actual load is usually the determining factor in the selection of bearing size. Roller bearings have a higher capacity than ball bearings with the same external dimensions. Usually ball bearings are suitable for light or medium loads, and roller bearings are suitable for heavy loads.

Only bear radial load can choose deep groove ball bearing and cylindrical roller bearing. Only bear axial load can choose thrust ball bearing and thrust cylindrical roller bearing . When there is radial load and axial load (combined load), angular contact ball bearings or tapered roller bearings are generally selected. If the radial load is large and the axial load is small, deep groove ball bearings and cylindrical roller bearings with ribs on the inner and outer rings can be selected. If there is also large deformation of the shaft or housing and poor installation alignment, spherical ball bearings and spherical roller bearings can be selected. If the axial load is large and the radial load is small, the thrust angular contact ball bearing can be selected. If the four point contact ball bearing also requires self-aligning performance, the thrust spherical roller bearing can be selected.

 

3.Rotating speed

The working speed of the rolling bearing mainly depends on its allowable operating temperature. Bearings with low frictional resistance and less internal heat generation are suitable for high-speed operation. When only bearing radial load, deep groove ball bearings and cylindrical roller bearings can reach higher speed. If bearing combined load, angular contact ball bearings should be selected. High speed can be achieved by specially designed high precision angular contact ball bearings. The rotational speed of various thrust bearings is lower than that of radial bearings.

 

4.Rotation accuracy

For most machinery, the selection of bearings with grade 0 tolerance is sufficient to meet the equipment requirements. But when there are strict requirements on the rotation accuracy of the shaft, such as machine tool spindles, precision machinery and instruments. Deep groove ball bearings with higher tolerance, angular contact ball bearings, tapered roller bearings, cylindrical roller bearings and thrust angular contact ball bearings should be selected.