The rigidity of a bearing is the force required to make the bearing deformation. The elastic deformation of rolling bearings is very small and can be ignored in most machines. However, in some machines, such as machine tool spindles, bearing rigidity is an important factor. Cylindrical and tapered roller bearings are generally used. Because the two types of bearings are subjected to load, the rolling elements and the raceways are in line contact, and the elastic deformation is small and the rigidity is good. All kinds of bearings can also be pre-tightened to increase the rigidity of the support. For example, angular contact ball bearings and tapered roller bearings, in order to prevent the vibration of the shaft and increase the rigidity of the support, a certain axial force is often applied at the time of installation to press them against each other. Of course, the pre-tightening amount should not be too large. If it is too large, the bearing friction will increase and the temperature rise will increase, which will affect the service life of the bearing.