Study On The Fault Diagnosis Of Rolling Bearing Andgear Under Variable Rotation Rate Based On Multi-source Signal

Rolling bearing and gear are the most basic machinery units and most widely used in mechanical components. In the real environment, since bearing and gear are in variable rotation rate condition, which cause them easily damage and affect the normal operation of mechanical components, so the study of rolling bearing and gear fault diagnosis under variable rotation rate condition has important practical significance.Firstly, this paper summarizes and analyzes the typical fault type and vibration mechanism of rolling bearing and gear. By comparison, the analysis of the non-stationary signal and stationary signal processing methods is discussed.Secondly, according to the study of the rolling bearing fault vibration signal under variable rotation rate, the empirical mode decomposition(EMD) is introduced into the process of feature extraction, which extracts the time-domain feature parameters and energy from the intrinsic mode function(IMF) to construct feature matrixes. At the same time, considering the influences of background noise in engineering practice, an improved wavelet threshold denoising method is used to denoise the vibration signal. Through the test of simulation data, the result is satisfying when the generalized regression neural network(GRNN) is applied to identify the fault features of rolling bearing.Thirdly, according to the research of gear fault vibration signal under rotation rate, the wavelet packet decomposition(WPD) and short-time Fourier transform(STFT) are introduced into the feature extraction process to construct gear fault feature matrixes under variable rotation rate respectively. Support vector machine(SVM) is used in gear fault feature recognition, Through the actual acquisition of gear vibration signal training SVM,the test results meet the requirements.Finally, using Machinery Fault Simulator as the research object, based on multi-source signal design the experimental scheme of rolling bearing and gear fault diagnosis experiment under variable rotation rate. Through the experiment, the rolling bearing and gear fault diagnosis method under variable rotation rate are respectively verified.The paper finally summarized the work, and the study of relevant technology is discussed as the future work.