Method of improving fan bearing support stiffness

The method of improving the bearing stiffness of fan.
1) The lower the surface roughness and the better the shape and position accuracy of the bearing installation position on the shaft and seat hole, the higher the support rigidity.
The surface strengthening treatment on the above surface is beneficial to improve the rigidity. The high hardness plug rod with low roughness is used to gently press in and out of the seat hole for many times with a certain interference under the lubricated state, which is also conducive to improving the support rigidity. If necessary, the snap ring can be used for similar treatment of the journal.
2) The bearing preload method is used to improve the support rigidity. The axial preload method can be adopted for ball bearings or tapered roller bearings, while the radial preload method can be adopted for short cylindrical roller bearings, which can significantly improve the rigidity of shaft support. At this time, either the bearing clearance is eliminated or a small negative clearance is obtained. However, when the speed is not too high and the temperature rise is small, it is best to adjust to a small negative clearance state.
When preloading is applied, the deformation should be measured continuously. Note that in the low value stage of deformation, the deformation is nonlinear with the increase of preload load; In the high value stage, the deformation is linear with the increase of load.
Once the linear relationship between deformation and load occurs, the increase of preload will be stopped immediately, and constant stiffness can be obtained at this time. Since then, there is a fixed relationship between the axial stiffness and radial stiffness of the bearing, which does not depend on the applied load.
For the measurement of the above deformation, for example, the method of butting the dial indicator against the appropriate part of the bearing end face or shaft and observing the change of its reading with the preload can be used. The preloading method has its disadvantages, such as increasing the friction torque, increasing the temperature rise and shortening the service life of the bearing. Therefore, it is necessary to comprehensively consider, weigh the gains and losses and select the appropriate preload.
3) Bearing configuration bearing configuration also has a great impact on bearing rigidity. Generally speaking, for centripetal thrust ball bearings and roller bearings, when used in pairs, it is appropriate to adopt the configuration with the large end face of the outer ring opposite (i.e. the pressure cone formed by its pressure line is outward). In this way, the anti overturning torque of the configured bearing is large, and the adjusted preload changes less when the temperature changes.
4) Using multi bearing support mode, under the condition of allowable axial position, each fulcrum adopts two or more bearings as radial support, which can improve the support rigidity.