Estimating the size of naturally generated defects in the outer ring and roller of a tapered roller bearing based on autoregressive model combined with envelope analysis and discrete wavelet transform

Vibration analysis has been widely used for condition monitoring and fault diagnosis of rolling element bearings. The next step is to determine defect size from the measured vibrations which can be used in the decision making about the bearing replacement. This paper presents an experimental investigation of the defect size estimation from the vibration signals of two types of naturally generated defects, on the outer race and roller of two tapered roller bearings. Vibrations are measured at different shaft speeds and loads. The signatures generated by the entry of the rolling elements into and exit from the defective area are enhanced by the autoregressive model and envelope analysis. The duration between these two events is used to estimate the size of natural defects. The accuracy of the results is compared with the results obtained by the autoregressive model and discrete wavelet transform. (C) 2020 Elsevier Ltd. All rights reserved.