On the premise that the machining error of the main shaft itself meets the requirements, the adjustment of the rotation accuracy of the main shaft of the planetary reducer and the rotation accuracy of the main shaft of the reducer are generally determined by the bearing. The key to adjust the spindle rotation accuracy is to adjust the bearing clearance. Maintaining a reasonable amount of bearing clearance is of great significance to the working performance and bearing life of the main shaft components of the planetary reducer.

For rolling bearings, working with large clearance will not only concentrate the load on the rolling body in the force direction, but also produce serious stress concentration at the contact of the inner and outer race raceways of the bearing, shorten the bearing life, and cause the centerline of the main shaft to drift, which is easy to cause the vibration of the main shaft components. Therefore, the adjustment of the rolling bearing of the planetary reducer must be preloaded to produce a certain amount of interference inside the bearing, causing a certain amount of elastic deformation at the contact between the rolling body and the inner and outer race raceways, so as to improve the rigidity of the bearing.