Comparative Study on Surface Contact Fatigue of Machine Tool Bearing Raceways with Different Rolling Elements: Two Failure Bearings Case Studies

Surface contact fatigue is one of the main failure modes of precision bearing, which can result in performance degradation, such as increased vibration or abnormal sound. By comparatively analyzing the damage characteristics of two types of failure bearings, hybrid ceramic ball bearing and steel ball bearing operating under real working conditions, the differences of the surface fatigue mechanisms are clarified. For hybrid ceramic ball bearing, the Si-contained hard particles detached from the surface of ceramic balls are squeezed into the surface of raceway, which leads to the micropits and surface cracks. For steel ball bearing, the cracks can initiate on the surface wrinkle regions (SWRs). The cracks originated from the cavities and microcracks can also form in the surface plastic deformation layer in the two types of bearings. The formation mechanisms of cracks on the surface and in the plastic deformation layer present synergistic effect, which results in the peeling band on the raceways together. From the damage characteristics of the two bearings in this study, it can be seen that the surface technology application might mitigate the surface fatigue in steel ball bearing application. Also, it is necessary to solve the problem of the peeling in ceramic balls to improve performance of anti-surface fatigue of hybrid ceramic ball bearings.

表面接触疲劳（Surface contact fatigue）是精密轴承的主要失效模式之一，可引发振动加剧、异响等性能退化问题。本研究通过对实际工况下运行的两类失效轴承——混合陶瓷球轴承（hybrid ceramic ball bearing）与钢制球轴承（steel ball bearing）的损伤特征开展对比分析，阐明了二者表面疲劳失效机制的差异。针对混合陶瓷球轴承，陶瓷球表面脱落的含硅硬质颗粒会被挤入滚道（raceway）表面，进而引发微凹坑与表面裂纹；针对钢制球轴承，裂纹易萌生在表面褶皱区（SWRs）。两类轴承的表面塑性变形层（surface plastic deformation layer）中，也可由空腔与微裂纹衍生出裂纹。表面与塑性变形层内的裂纹形成机制存在协同效应，二者共同作用最终导致滚道上形成剥离带（peeling band）。基于本研究中两类轴承的损伤特征可知，表面处理技术（surface technology）的应用或可缓解钢制球轴承的表面疲劳问题；同时，需解决陶瓷球的剥离问题，以提升混合陶瓷球轴承的抗表面疲劳性能。