Modelling Of Rolling Bearing Outer Race Fault Mechanism And Extraction Of Double Impacts Feature

Rolling bearing, which is used for supporting the rotor rotation, is widely used in rotating machinery and it’s one of the most prone to failure part in rotating machinery. When a rolling element through the defect in rolling bearing, on the edge of entry or exit, there is an impact pulse due to the contact between the rolling element and raceway. Its impact pulse amplitude and waveform is directly related to the race defect size, and according to the contact between rolling element and raceway defect edge, the vibration signal appears the phenomenon of double impact. Through double impact vibration signal analysis, the result can be used to judge the defect degree. And the result can help realize the estimated residual life of the rolling element bearing.In order to achieve accurate and effective for fault rolling bearing double impact vibration signal feature extraction and analysis, rolling bearing fault mechanism analysis should be the first step, and then build the double impact dynamics model of rolling bearing fault. This model can provide a theoretical support for double impact feature extraction of vibration signal.Based on the deep groove ball bearing as the research object, as an example of a single peeling defects existing in rolling bearing outer raceway, there is a detailed analysis of the rolling bearing fault when the rolling element through the defect in the raceway, including the change of displacement and contact force. Based on normal rolling bearing dynamic model, a new model about double impact is proposed in this paper. By solving the differential equations of fault dynamic model, the calculation results of the double impact characteristics is consistent with the theoretical analysis results.In terms of rolling bearing double impact feature extraction, in order to extract rolling bearing fault feature better and more accurate from vibration signal, there is a study about noise reduction in vibration signal. An improvement fast kurtogram based on the average of sub-band spectral kurtosis has been presented in the paper. The method can effectively eliminate or weaken the influence of pulse interference on the result of fast kurtogram. In order to achieve accurate extraction of bearing fault feature from compound fault in gearbox, a method for bearing fault diagnosis based on cepstrum editing and time domain synchronous average is proposed in this paper. This method can realize the automation of cepstrum editing.Cooperate with deep groove ball bearing outer ring raceway single local peeling defect fault as an example to carry on the fault simulation test, through the analysis of vibration signals, by the analysis of double impact characteristics of rolling bearing, the test results and the theoretical calculation results of fault rolling bearing dynamic differential equations is consistent. The results verify the effectiveness of the fault rolling bearing double impact dynamics model.