【作者】 陆小明；

【导师】 王金娥；

【作者基本信息】 苏州大学 ， 机械电子工程， 2012， 硕士

【摘要】 滚动轴承是工业生产中使用最广泛的机械零件，也是机械设备的重要故障源之一。准确判断轴承工作状态直接关系到整台机组乃至整条生产线的生产质量和安全。研究滚动轴承的监测和诊断技术，对于避免重大事故及变革维修体制等具有重要的理论研究价值和实际应用意义。本文首先对滚动轴承的振动特性进行了研究，得到滚动轴承分别在内圈、外圈以及滚动体存在缺陷时的时频特性。对所采集的振动信号中的若干问题，如存在奇异点、趋势项和较强的噪声，进行了研究，提出了冗余二代小波去噪法，有效地去除了信号中的噪声成分，提高了信号的信噪比。同时利用EMD去趋势项法消除了采集信号中的趋势项。其次，在对EMD基本理论、算法及其特性进行研究的基础上，针对EMD在实际运用中存在的端点效应、模态混合及虚假模式等问题进行了研究，提出了有效解决这些问题的方法：把支持向量机和窗函数有机结合起来，消除了EMD的端点效应；利用EEMD法解决了模态混合问题；根据滚动轴承的振动特性，以峭度为参数，很好地提取出含有故障信息的固有模态函数，使EMD具有更大的实用价值。最后，在此基础上，提出了IEEMD-SK滚动轴承故障诊断法。仿真与实验证明，该方法可以有效提取出滚动轴承的故障特征频率，使故障诊断结果更准确。更多还原

【Abstract】 Rolling element bearing is one of the most widely used components for industrialproduction as well as one is easily damaged in an mechanical equipment.Its workingcondition has influence on product quality and working safety in industry directly.So itis very significant to research on bearing condition monitoring and fault diagnosistechniques,especially for bearing early fault.In this paper,first study on vibration characteristics of the rolling element bearingand time-frequency characteristics of bearing when there is an defect in the inner ring,outer ring or rolling element is gained. Then, a certain number of problems in the actualacquisition vibration signals, such as the existence of singular points, the trend and thestrong noise, are studied. EMD is used to eliminate the trend of the acquisition signal,and The Second generation redundant wavelet denoising method are adopted toeliminate the noise components in the signal, and improves the signal-to-noise ratioeffectively.Then, on the basis of EMD basic theory, algorithm and its characteristics,study onend effect,mode mixture and false modes of EMD, and put forward the effectivesolutions to these problems: the support vector machine and window function werecombined to eliminate EMD end effect; the problem of mode mixing was solvedby using the EEMD method; according to the vibration characteristics of rolling bearing,kurtosis was used to chose the intrinsic mode functions containing faultinformation. Through these improvements make EMD a more practical tool.Finally, IEEMD-SK rolling bearings fault diagnosis method was put forward on thebase of these improvements, and prove that this method can extract the frequency ofrolling bearing fault quickly and accurately through the experiment.更多还原