When applying bearing preload, it is recommended to continuously measure deformation. It should be pointed out that this deformation is nonlinear. In the low deformation stage, the load in the high deformation stage is increased, and in the high deformation stage, the linear pre tension load is increased. There is a linear relationship between the main deformation and the load. The increase in pre tension force immediately stops, and constant stiffness can be obtained. Afterwards, there is a fixed relationship between the stiffness of axial and radial bearings, which is not dependent on external loads.

1. Equipped with bearings, the bearing structure has a significant impact on bearing stiffness. Generally speaking, centripetal thrust ball bearings and roller bearings have larger outer rings that have the ability to resist overturning torque for bearings. When the temperature changes, the preload adjustment will not change too much.

2. Under the allowable axial position conditions, the support stiffness can be improved by using multiple bearing supports and two or more radial bearing supports at each support point. In recent years, axial preload and multiple sets of centripetal 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. Case-hardening is beneficial to improve hardness. Under lubrication conditions, gently press the extremely low hardness high hardness plug multiple times into and out of the seat hole, and there is some interference, which is also beneficial for improving the support stiffness. If needed, it is similar to using a clamping ring to handle the journal.

4. The bearing preloading method can be used to improve bearing stiffness. 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 by placing probes on the surface of the inlet bearing or on appropriate parts of the shaft with preload, for example. The pre tightening method has shortcomings such as increasing bearing friction torque, increasing temperature rise, and shortening service life. Therefore, it is necessary to comprehensively consider and weigh the gains and losses, and choose a suitable pre tightening method.