Two methods of acoustic emission and vibration in the application of rolling bearing fault diagnosis of crack are studied,and the superiority of these two methods in the early fault diagnosis are compared. The electric spark technology is adopted to make two kinds of cracks,0.5 mm and 0.8 mm,on the inner ring of roller bearing,to simulate the inner ring crack fault of rolling bearing under the actual condition. In both low speed(10 r/min) and high speed(1 000 r/min) cases,through testing,the acoustic emission and vibration signals are measured respectively for two kinds of crack faults of rolling bearing. The time-frequency characteristics of vibration and acoustic emission signals under different rotating speed and crack faults of the rolling bearing are analyzed and compared. Waveform analysis and envelope spectrum analysis of the signal data are conducted. The experimental results show that the acoustic emission signal has nothing to do with the modulation signal;therefore the acoustic emission signal envelope spectrum analysis can effectively analyze the fault characteristic frequency of the signal. Under the condition of weak fault,acoustic emission signal is more sensitive than vibration signals,while vibration signal is more accurate for diagnosing more serious fault,which means the acoustic emission technology is more conducive to early detection of fault,and acoustic emission technology can be used as the supplement of the vibration analysis technique for fault detection.%对声发射和振动两种方法在滚动轴承裂纹故障诊断中的应用进行了研究,并比较了这两种方法在早期故障诊断中的优越性.采用电火花技术在滚动轴承内圈加工宽度为0.5 mm和0.8 mm的两种裂纹,模拟在实际情况下的滚动轴承内圈裂纹故障.在低速(10 r/min)和高速(1000 r/min)两种情况下,通过试验分别测得滚动轴承两种裂纹故障状态下的声发射信号和振动信号.分析比较了不同转速、不同裂纹故障状态下的轴承振动和声发射信号的时频特征.对信号数据进行波形和包络谱分析.试验结果表明:声发射信号与调制信号无关.对声发射信号进行包络分析,可以有效分析信号的故障特征频率.在故障微弱情况下,声发射信号比振动信号更具敏感性;当故障强度较大时,采用振动方法诊断更为准确,即声发射技术更有利于故障的早期检测.声发射技术可作为振动分析技术的补充,用于故障检测.
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