Precise measurement of defect width in tapered roller bearing using vibration signal

Abstract

The present experimental investigation is focused on establishing a robust signal processing technique to measure the width of the defect present on the outer or inner race of a tapered roller bearing. An experiment has been designed with roller bearings having various widths of seeded faults, on outer and inner races, respectively. The corresponding vibration signals have been investigated with the proposed method. This method initially denoises the vibration signal using un-decimated wavelet transform. The approximation signal has been shown to be effective for further time–frequency analysis using continuous wavelet transform (CWT). It is not only difficult but ambiguous as well to detect the entry and the exit points of the defect. The ambiguity gets reduced by using Symlet wavelet due to its linear phase nature which maintains sharpness in the signal even when there is a sudden change in signal. In the first phase of the measurement, the scalogram generated from CWT is used to measure the time duration that the roller takes to roll over the defect. However, measurement process is dramatically enhanced with the proposed ridge spectrum, which is generated from the CWT scalogram. The vertical strips drawn on the ridge spectrum corroborates well with defect width. Summarizing, the proposed method can be reckoned suitable and reliable in measuring bearing defect width in real-time from vibration signal.