Improved calculation method for fault characteristic frequency of bearing with local defect on rolling element considering kinematic characteristics of raceways

Abstract

The fault characteristic frequency of rolling bearing (RB) is widely used in fault diagnosis, and the theoretical values of fault characteristic frequencies currently used for studying local defect on rolling element (LDRE) are derived based on the self-rotation speed of the rolling element (RE). However, particularly in the case of supporting bearings, the inner raceway is rotated with the shaft while the outer raceway is fixed. This results in different kinematic properties of different raceways in contact with LDRE. Therefore, based on the different types of kinematic characteristics, fault characteristic frequencies of RE contacting with the different raceways have been derived respectively. The proposed frequencies are proved by experiment results and the benchmark data sets of bearing. Because the transmission path generated by LDRE contacting with the outer raceway is shorter than that generated by the inner raceway, the vibration response generated by LDRE contacting the outer raceway are more obvious. Therefore, combining the characteristic frequency of LDRE contacting with the inner raceway(fFRCI) with that of LDRE contacting with the outer raceway(fFRCO) can reduce misdiagnosis rate. The proposed fFRCO and fFRCI will provide a theoretical foundation for the fault diagnosis and condition monitoring of RBs.