The use of Level Crossing Rate for estimation of bearing defect size

In this paper a new approach to determine the defect size of rolling element bearings is proposed. This approach is based on the statistical characteristics of the vibrations signals generated by rolling element bearings. Although some statistical parameters such as RMS and kurtosis have some capabilities to detect the bearing faults, these parameters for accurate estimation of defect size are not adequate. For the first time in this study the number of level crossings of a specific level is introduced as a suitable parameter for rolling bearing defect size estimation. The acceleration signal of rolling bearings has been measured and crossing analysis showed that the number of crossings is proportional to the defect size on inner and outer races. The results of experimental tests proved that this parameter can determine the defect length of rolling bearings with a good approximation.