Flexible thin-walled bearing life testing machine and data analysis

In a harmonic reducer, the precision flexible thin-walled bearing (FTB), which is the core component, achieves the high reduction ratio requirement through its elastic deformation. The lifespan of a harmonic reducer mainly depends on this FTB. The special load conditions make it easy for the inner and outer rings, as well as the rolling elements, to suffer damage. The outer ring is especially prone to fatigue failure. Therefore, analyzing the dynamic response and fatigue life of FTBs under complex operating conditions is crucial for ensuring their reliability and durability. This paper designs a vibration-based fault diagnosis and lifespan testing machine to study the load conditions and kinematic characteristics of FTB in harmonic reducers. We derive a model for solving the fault characteristic frequencies of the inner and outer rings and rolling elements of FTB with elliptical characteristics. The results show that the fault characteristic frequencies of FTB vary within a range, whereas those of conventional bearings are fixed values. Additionally, normal FTBs contain periodic impact components in their vibration signals. In contrast, conventional bearings only produce such periodic impacts when damaged.