Vibration analysis and fault diagnosis of thin-walled bearing in harmonic reducer under periodic loading

Abstract

Thin-walled bearings, core transmission components of harmonic reducers, are prone to failure under alternating loads. This study experimentally investigates the relative rotation between the thin-walled bearing’s outer ring and the flexspline under periodic loads and analyzes its impact on the fault characteristic frequency. It also examines the vibration characteristics of thin-walled bearings in harmonic reducers under different health conditions, revealing that these characteristics are influenced by the outer ring’s relative rotation and differ significantly from those of ordinary bearings. In cases of local faults in the inner and outer ring of the thin-walled bearing, the fault characteristic frequency experiences complex modulation involving multiple frequencies. Moreover, the outer ring’s rotation induces noticeable frequency fluctuations in both the fault characteristic frequency and its modulation frequencies. Results from the harmonic reducer’s fatigue life experiments show that the conclusions of this study can be applied to fault diagnosis in harmonic reducers. This research offers valuable technical insights into exploring fault mechanisms and developing fault diagnosis methods for harmonic reducers.