The application feedback on existing silicon nitride ceramic bearings and RCF experimental research all indicate that the primary failure mode of silicon nitride ceramic bearings is material spalling on the contact surface. Spalling failure occurs due to the initiation and propagation of cracks under rolling contact. However, silicon nitride ceramic bearings, owing to their unique manufacturing method, inevitably exhibit defects and cracks. Therefore, as silicon nitride ceramic bearings are increasingly prevalent, reducing the probability of spalling failure is crucial for extending their service life. This can only be achieved by gaining a clear understanding of the crack initiation and expansion mechanisms in silicon nitride ceramic bearings. This paper is based on silicon nitride rolling friction experiments. It involves the joint simulation of Franc3D-V8.4 and ABAQUS2020, wherein the crack front SIFs are calculated for each load contact position of the surface crack on the silicon nitride ceramic bearing ring during cyclic movement. The study also delves into the determination of the maximum effective stress intensity factors and explores the influence of the initial crack depth on the cycle life and direction of crack propagation. The research yields several valuable conclusions. The findings of this research offer theoretical guidance for formulating grinding technologies for silicon nitride rings and adjusting and controlling working parameters of silicon nitride ceramic ball bearings. These insights are crucial for enhancing the reliability and longevity of silicon nitride ceramic bearings in practical applications.

In order to verify that the silicon nitride all-ceramic ball bearings have more excellent high-speed performance, thermal rise and vibration are the two main factors that restrict the bearing to move at high speed. In this manuscript, based on the establishment of the mechanical model of bearings, the structural model of all ceramic motorized spindle-bearings is established. The temperature field of the motorized spindle-bearing system is simulated through analysis of bearing heat generation. The thermal rise of silicon nitride all-ceramic ball bearings was tested by setting up all ceramic motorized spindle-bearing test platform under the operating speeds of 6,000, 9,000, 12,000, 15,000 and 18,000 rpm respectively, the results are compared with the simulation results. Vibration characteristics of the all-ceramic ball bearings were compared with those of similar steel bearings. The test results show that the thermal rise of all-ceramic ball bearings gradually tends to be stable at different rotational speeds after the running time exceeds 15 minutes, no-load thermal rise is less than 10°C, the maximum temperature of ceramic bearing is nearly 10 °C lower than the maximum temperature of the simulated metal bearing. With the increase of rotating speed, the maximum amplitude of metal bearing without loading is 2.38 times of that of ceramic bearing. The conclusion shows that ceramic bearings have better dynamic characteristics and stable reliability than metal bearings, so they have better high-speed performance, providing reference value for the future design of the same type of all-ceramic bearings.