Which factors must be considered in bearing selection?
Posttime：2021-05-07 Hits：542Which factors should be considered in bearing selection?
"Various types of bearings have different characteristics due to their different designs.Due to the changability and complexity of the specific installation position and application occasions of bearings, there is no fixed mode for the selection of bearing types to adapt to the specific installation position and application conditions of a host machine. When choosing bearing types, it is suggested to consider comprehensively the following main factors.
Allowed space:
When mechanical design, generally determine the size of the shaft, and then choose the bearing according to the size of the shaft.Usually, the small shaft selection of ball bearings;Large shaft selection of cylindrical roller bearings, self-aligning roller bearings, tapered roller bearings (sometimes can also choose ball bearings).If the radial space of the bearing installation part is limited, the bearing with a smaller radial section height should be used.Such as needle roller bearings, some series of deep groove ball bearings, angular contact ball bearings, cylindrical roller or self-aligning roller bearings and thin-walled bearings.If the axial space of the bearing installation part is limited, a bearing with a smaller width can be used.
Bearing load:
Load size The load size is usually the determining factor in selecting the bearing size.Roller bearings have greater bearing capacity than ball bearings with the same overall dimensions.Usually ball bearings are suitable for light or medium load, roller bearings are suitable for bearing heavy load.
For pure radial load, deep groove ball bearing and cylindrical roller bearing can be selected.Thrust ball bearing and thrust cylindrical roller bearing can be used for pure axial load.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, the deep groove ball bearing and the cylindrical roller bearing with the inner and outer rings have the flange can be selected.If there is also a large deformation of the shaft or shell and the installation of neutral difference, self-aligning ball bearings and self-aligning 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 the self-aligning performance, the thrust self-aligning roller bearing can be selected.
Speed:
The working speed of rolling bearing mainly depends on its allowable operating temperature.Bearings with low friction resistance and less internal heat are suitable for high speed operation.Under radial load, deep groove ball bearing and cylindrical roller bearing can reach a higher speed, if under combined load, angular contact ball bearing should be selected.High precision angular contact ball bearing with special design can achieve high speed.The speed of all kinds of thrust bearings is lower than that of radial bearings.
Rotation accuracy:
For the majority of machinery, choose a level 0 tolerance of bearing is enough to meet the requirements of the host, but on the axis of rotation accuracy have strict requirements, such as spindle, precision machinery and instrument etc., should choose high tolerance grade of deep groove ball bearings, angular contact ball bearings, tapered roller bearings, cylindrical roller bearings and thrust angular contact ball bearings.
Rigid:
The rigidity of rolling bearings is determined by the elastic deformation when they bear the load. In general, this deformation is very small and can be ignored. But in some machinery, such as machine tool spindle system, the static stiffness and dynamic stiffness of bearings have a great influence on the characteristics of the system.In general, roller bearings have higher stiffness than ball bearings.All kinds of bearings can also improve the rigidity of different degrees by properly "pretightening".
Noise and vibration:
The noise and vibration of the bearing itself are generally very low.But for small and medium-sized motors, office machinery, household appliances and instruments, which have special requirements for noise and running stability, low noise bearings are usually selected.
"Various types of bearings have different characteristics due to their different designs.Due to the changability and complexity of the specific installation position and application occasions of bearings, there is no fixed mode for the selection of bearing types to adapt to the specific installation position and application conditions of a host machine. When choosing bearing types, it is suggested to consider comprehensively the following main factors.
Allowed space:
When mechanical design, generally determine the size of the shaft, and then choose the bearing according to the size of the shaft.Usually, the small shaft selection of ball bearings;Large shaft selection of cylindrical roller bearings, self-aligning roller bearings, tapered roller bearings (sometimes can also choose ball bearings).If the radial space of the bearing installation part is limited, the bearing with a smaller radial section height should be used.Such as needle roller bearings, some series of deep groove ball bearings, angular contact ball bearings, cylindrical roller or self-aligning roller bearings and thin-walled bearings.If the axial space of the bearing installation part is limited, a bearing with a smaller width can be used.
Bearing load:
Load size The load size is usually the determining factor in selecting the bearing size.Roller bearings have greater bearing capacity than ball bearings with the same overall dimensions.Usually ball bearings are suitable for light or medium load, roller bearings are suitable for bearing heavy load.
For pure radial load, deep groove ball bearing and cylindrical roller bearing can be selected.Thrust ball bearing and thrust cylindrical roller bearing can be used for pure axial load.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, the deep groove ball bearing and the cylindrical roller bearing with the inner and outer rings have the flange can be selected.If there is also a large deformation of the shaft or shell and the installation of neutral difference, self-aligning ball bearings and self-aligning 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 the self-aligning performance, the thrust self-aligning roller bearing can be selected.
Speed:
The working speed of rolling bearing mainly depends on its allowable operating temperature.Bearings with low friction resistance and less internal heat are suitable for high speed operation.Under radial load, deep groove ball bearing and cylindrical roller bearing can reach a higher speed, if under combined load, angular contact ball bearing should be selected.High precision angular contact ball bearing with special design can achieve high speed.The speed of all kinds of thrust bearings is lower than that of radial bearings.
Rotation accuracy:
For the majority of machinery, choose a level 0 tolerance of bearing is enough to meet the requirements of the host, but on the axis of rotation accuracy have strict requirements, such as spindle, precision machinery and instrument etc., should choose high tolerance grade of deep groove ball bearings, angular contact ball bearings, tapered roller bearings, cylindrical roller bearings and thrust angular contact ball bearings.
Rigid:
The rigidity of rolling bearings is determined by the elastic deformation when they bear the load. In general, this deformation is very small and can be ignored. But in some machinery, such as machine tool spindle system, the static stiffness and dynamic stiffness of bearings have a great influence on the characteristics of the system.In general, roller bearings have higher stiffness than ball bearings.All kinds of bearings can also improve the rigidity of different degrees by properly "pretightening".
Noise and vibration:
The noise and vibration of the bearing itself are generally very low.But for small and medium-sized motors, office machinery, household appliances and instruments, which have special requirements for noise and running stability, low noise bearings are usually selected.
