Ball bearings are critical machine components that ensure smooth and efficient machine operations. Therefore, frequent monitoring of their operating conditions and health is highly desirable. This would help in prediction, diagnosis, and monitoring of the various bearing failures. Presently, various bearing fault diagnosis technologies have been developed. Unfortunately, most of these methods focus more on size estimation and fault pattern recognition without taking into consideration the effects of the angle position of the outer bearing ring. Additionally, understanding fault mechanism and signal processing have enabled the extraction of relevant fault features for more accurate fault diagnosis.
Researchers have explored before the dynamic behaviors of the bearing to understand the ball bearing mechanism, which is an essential step in defect detection and fault diagnosis. Presently, bearing fault diagnosis is grouped into identifying the existing faults, determining the failure mode and quantifying the available information on the fault. However, in most studies, bearing fault diagnosis does not include estimating the defect position of the ball bearing. This is normally affected by the different angle position of the outer ring fault due to its influence on the residual life. Alternatively, the localization diagnosis of the bearing outer ring fault plays an essential role in fault analysis. For instance, a horizontal-vertical synchronized root mean square index (HVSRMS) have been recently used in the localization diagnosis of bearing outer ring fault. Despite the significant improvement, the accuracy of HVSRMS has not been proved due to several drawbacks like the difficulty in predicting whether the fault is on the left or right side of the angle.
Beijing University of Technology researchers: Dr. Lingli Cui and Dr. Jinfeng Huang together with Dr. Feibin Zhang and Dr. Fulei Chu at Tsinghua University developed a localization diagnosis method based on the HVSRMS localization law and localization formula for accurate diagnosis of the angle position of the outer ring fault. First, the authors established a nonlinear contact model to investigate the changes in the localization laws when the angular position of the outer ring fault is on both sides of 270°. This specifically helped in the development of the localization law. The main objective was to improve on the accuracy of the localization diagnosis of the bearing outer ring fault. The work is currently published in the journal, Mechanical Systems and Signal Processing.
The authors obtained the mapping relationship between the HVSRMS and the outer ring fault angle position. The contact force decreased rapidly for both the faults on the left and right side of 270° while the direction of the forces was negative and positive respectively. Additionally, it was worth noting that the localization law of the ball bearing outer ring fault was favorable for the measured signals. In general, combination with the localization law significantly improved the HVSRMS localization formula thus improving the overall accuracy of the proposed method. Altogether, the study provides new insights that will advance diagnosis and failure prediction in defective bearings.
Cui, L., Huang, J., Zhang, F., & Chu, F. (2019). HVSRMS localization formula and localization law: Localization diagnosis of a ball bearing outer ring fault. Mechanical Systems and Signal Processing, 120, 608-629.Go To Mechanical Systems and Signal Processing