Experimental Study On Characteristics Of Achoustic Emission Waveform Streaming With Different Kinds Of Faults For Rolling Bearing

The rolling bearing is a kind of precise machinical component,and is widely used in machinical equipment.The running state of rolling bearing has a direct impact on the safety of the whole machine.When the rolling bearing is in the fault state,the abnormal sound signal is produced in the running process.Compared with the vibration signal,the frequency range of the acoustic emission is wider,and the high frequency signals can effectively restrain other low frequency interference signals for fault diagnosis.However,the traditional signal acquisition technique of acoustic emission is intermittent and not continuous,and is unable to complete the periodic signal acquisition,the technology of acoustic emission waveform streaming can record the waveform data into the physical memory of the computer continuously,and the acquisition of acoustic emission signals with fixed length can be achieved with the high sampling rate,so that the coutinuous acoustic emission signals can be collected in real time and long time.In addition,when the technology of acoustic emission waveform streaming is used for analyzing the signals,not only the multi period waveform data can be seen,but also local waveform can be analyzed by amplifying.The acoustic emission signals of rolling bearing are cyclical,so signals collection of rolling bearing by this method can reflect the advantages of waveform streaming.Based on the model of rolling bearing N205 EM and NU205 EM as the research objects,the main fault forms of rolling bearing and the cause are analyzed,the calculation of rolling bearing is calculated,the occurrence and types of the rolling bearing fault are judged by comparing the measured frequency and the natural frequency of rolling bearing.Fault simulation test system for rolling bearing is builded,the outer ring,the inner ring and the rolling body of three rolling bearings are man-made destructed,and the method of EDM is used in the corresponding parts of the bearing.The acoustic emission waveform streaming and vibration signal with different kinds of faults under different speed are collected through fault simulation test system for rolling bearing.The vibration signal and the acoustic emission waveform streaming of rolling bearing are compared by means of time-domain analysis,vibration signal is more sensitive in low speed.Acoustic emission waveform streaming has the obvious periodic characteristcs with the increase of the rotating speed,which can better characterize the fault.Acoustic emission waveform streaming with fixed period can be analyzed to judge the occurrence of the fault.Acoustic emission waveform streaming of rolling bearing can be analyzed by using the method of short-time energy,the signal collected by the technology of acoustic emission waveform streaming has obvious periodicity when the speed is high,the method of short-time energy can determin the production of the fault.Rolling bearing is the research object in this paper,and the fault mechanism is studied,the outer ring,the inner ring and the rolling body of three rolling bearings are man-made destructed,EDM is used in the corresponding parts of the bearing.Acoustic emission signals and vibration signals with normal state and abnormal states.are collected via the rotating machinery fault experiment platform.The methods of time-domain analysis and short-time energy are used to analyze the acoustic emission signals and vibration signals,and whether the fault is occurred can be determined preliminarily.Signal characteristics with the technology of acoustic emission waveform streaming are analyzed,and the signals of rolling bearing show obvious periodictity when the speed is high.Spectrum analysis is used for the acoustic emission waveform streaming signals and vibration signals of rolling bearings respectively.The occurrence of the fault can be judged by the analysis of envelope spectrum and power spectrum,but due to the influence of the noise,it is unable to extract the measured frequency of rolling bearing in the operation process,and therefore can not determine the specific kinds of faults accurately.Bispectrum analysis combined with the envelope specific is used to analyze the acoustic emission waveform streaming signals.The peak frequency with differnet kind of faults in running process can be obtained through three-dimensional map,contour map and slice map,and it has good consistency with the theoretical value of the intrinsic frequency,the early fault diagnosis of rolling bearing can be realized.