Diagnosis of early failures of bearing within mechanisms susceptible to unbalance and misalignment

Abstract

In this paper, we study the unbalance and misalignment effect on the acceleration vibration parameters commonly used in the diagnosis of early bearing failures. This research provides a diagnostic parameter called AFC.  Measurements of the AFC parameter are sensitive to the existence of the defect; however, misalignment, unbalance and their interactions do not cause a statistically significant effect in their values. The purpose of finding this parameter is to avoid false alarms or cover up faults in bearings within mechanisms susceptible to unbalance and misalignment. Among the methods studied, there are the spectral analysis, the study of global values ​​of the acceleration measurement with different processing like the high-frequency detection HFD, the acceleration envelope ENV, the kurtosis K, the crest factor FC and the asymmetry of the signal Ske, among other parameters proposed by the authors. In this regard, an experimental device was built, and a multilevel factorial experiment (2³) was designed where the factors were bearing damage, unbalance and misalignment. Three replicates were performed (24 experimental units).