When applying pre tightening force to the bearing, it is recommended to continuously measure the deformation. It should be pointed out that this deformation is nonlinear. Increasing the load in the low deformation stage and the linear preload in the high deformation stage results in a linear relationship between the main deformation and the load. The increase in preload immediately stops, and a constant stiffness can be obtained. Afterwards, there is a fixed relationship between the stiffness of axial and radial bearings, which does not depend on external loads.
1. Equipped with bearings, the bearing structure has a significant impact on the stiffness of the bearings. Generally speaking, radial thrust ball bearings and roller bearings have a larger outer ring end face, which provides the bearing with the ability to resist overturning torque. When the temperature changes, there will not be significant changes in the preload adjustment.
2. Under allowable axial position conditions, the support stiffness can be improved by using multiple bearing supports and two or more radial bearing supports at each pivot point. In recent years, axial preload force and multiple sets of radial thrust bearings have been widely used in the assembly of machine tool spindles.
3. In order to meet the requirements of Swedish bearing mating surfaces, better shaft and seat hole shapes, bearing installation positions, positional accuracy, lower surface roughness, and higher support stiffness. Surface hardening is beneficial for improving hardness. Under lubrication conditions, gently press the high hardness plug with extremely low hardness into and out of the seat hole multiple times, and there may be some interference, which is also beneficial for improving the support stiffness. If necessary, it is similar to using a clamping ring to handle the shaft neck.
4. The bearing preloading method can be used to improve the stiffness of bearings. The bearing pre tightening method can be used for ball bearings or bearings, while the radial pre tightening method can be used for short cylindrical roller bearings, which can significantly improve the stiffness of the shaft. At this point, remove the bearing clearance or obtain a small negative clearance. However, when the speed is not too high and the temperature is not too high, try to adjust the negative gap as small as possible.
These deformations can be observed, for example, by placing probes on the surface of bearings or on appropriate parts of shafts with preloads. The pre tightening method has shortcomings such as increasing bearing friction torque, improving temperature rise, and shortening service life. It should be comprehensively considered, weighed, and a suitable pre tightening method should be selected.

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