Study On Wear Performance Of Silicon Nitride Ceramic Ball Bearings

Bearings play an important role in mechanical equipment,and the running accuracy of bearings directly affects the machining accuracy of mechanical equipment.As the bearing working environment becomes more and more demanding,the traditional steel bearing can not meet the demand of harsh working environment such as high temperature and high speed.Ceramic materials are considered to be ideal materials for rolling bearings due to their excellent physical and chemical properties.Research shows that wear is one of the main failure modes of ceramic bearings.The research on the wear of ceramic bearings is of great significance for evaluating the running accuracy of mechanical equipment and predicting the service life of ceramic bearings.In this paper,the wear performance of silicon nitride ceramic bearings is studied,and the following aspects are carried out.Firstly,a quasi-static model and a wear depth calculation model for rolling bearings are established.Abandoning the raceway control theory,considering the centrifugal force and gyroscopic effect of the rolling element during high-speed running of the rolling bearing,a pseudo-static model for analyzing the running condition of the rolling bearing and the rolling element is established.Considering the non-uniformity distribution of the contact stress on the contact area between the rolling element and the raceway,the Archard model is modified.Combined with the load and velocity of the rolling element calculated by the pseudo-static model,the calculation model of the rolling bearing wear depth is derived.Secondly,the wear properties of silicon nitride ceramic materials were studied.Experiments and finite element numerical simulations were carried out for the evolution of friction coefficient,wear morphology,formation cause and wear coefficient of silicon nitride ceramics(Si3N4)under different load and lubrication conditions.The Rtec friction and wear test machine was used to carry out the wear test of the silicon nitride cylindrical pin and the block.The wear surface morphology of the wear after the wear test was measured by 3D laser microscope,and the wear profile of the friction pair was obtained.Establish a finite element model of the silicon nitride cylindrical pin and block,and develop a Umeshmotion subroutine for calculating the wear depth based on the modified Archard model.A simulation analysis method for the wear process of silicon nitride ceramics based on finite element numerical method and user subroutine is proposed.The ALE adaptive grid technique is applied to solve the mesh distortion problem in the wear process.The finite element simulation reveals the distribution characteristics of the contact stress of the wear interface and the variation law with the wear cycle,and explains the evolution of the wear morphology characteristics in the experiment.Based on the experimentally obtained wear surface morphology and the wear profile obtained by finite element simulation,the wear coefficient of the silicon nitride ceramic material was determined.Finally,the parameterization study on the wear performance of silicon nitride ceramic ball bearings was carried out.Considering the working conditions experienced by silicon nitride all-ceramic ball bearings in actual work,the effects of lubrication conditions,bearing pre-tightening force,rotating speed and external load on bearing wear were studied.The work of this paper provides a theoretical basis for exploring the factors affecting the wear of silicon nitride ceramic ball bearings,optimizing structural parameters and predicting the precision life.