Vibration characteristics analysis of double row tapered roller bearing with slight damage to the raceway

• Reveals distinct vibration patterns of scratched bearings during cold start versus normal ones. • Identifies limitations of single traditional time-frequency methods in detecting weak raceway faults. • Proposes a combined EMD-Wavelet approach that effectively identifies inner raceway defects. This article focuses on the evolution of vibration characteristics of double row tapered roller bearings with weak damage to the raceway from cold start to temperature stability. Firstly, the dynamic changes in temperature and vibration of bearings during cold start were analyzed. After the operating state stabilized, two traditional time-frequency analysis methods, empirical mode decomposition (EMD) and wavelet transform, were used to process the acceleration vibration signals of bearings. Analysis has found that the signals processed by a single traditional method are still difficult to clearly and quickly identify fault characteristics. On this basis, this article proposes a joint analysis method based on EMD and wavelet transform, and processes the same set of original vibration data. The results show that during the cold start process, the amplitude and rate of acceleration changes in the scratched raceway bearings are significantly different from those in normal bearings. After the temperature is stable, traditional methods have poor performance in identifying raceway scratches. The joint analysis method of EMD and wavelet transform can effectively identify faults in the inner raceway of bearings. This study provides an effective analytical method for accurately identifying early damage to bearings under different operating conditions such as cold start and stable operation.