摘要
柔性椭圆轴承(Elliptically shaped baring,ESB)在工作中承受循环交变应力载荷,是谐波减速器中最易损坏的核心零件。根据ESB的运动学特性,推导其滚道表面发生局部缺陷故障时的特征频率公式。由于其故障特征容易被长短轴交替产生的振动激励信号所掩盖,提出连续Morlet小波变换(ContinuousMorletwavelettransform,CMWT)与基于FFT的Hilbert频谱分析(FFT based Hilbert,FH)结合的CMWT-FH故障特征提取方法。与普通FH方法的特征提取效果对比分析,CMWT-FH方法可以更容易、更准确地识别出ESB的故障特征频率及其边频带频率:外圈故障时,外圈故障特征频率及其高次倍频两侧存在间隔为二倍转频调制频率的边频带;内圈故障时,内圈故障特征频率及其高次倍频两侧存在间隔为转频调制频率的边频带。可结合故障特征频率及调制边频带来判断故障出现在外圈还是内圈。
Elliptically shaped bearing(ESB)is the most easily damaged core component of harmonic drive under cyclic load of alternating stress.In order to diagnose the fault on raceway surface of ESB,the formulas of fault feature frequency is derived by using the kinematics equations of ESB.Considering the effect of characteristic excitation of vibration produced by alternating between long axis and short axis,the fault features of ESB are easily concealed.A method called CMWT-FH which is based on continuous Morlet wavelet transform and FFT-based Hilbert spectrum analysis is proposed for fault feature extraction.Compared with the conventional FFT-based Hilbert method,the proposed CMWT-FH method can identify fault feature frequency and its sideband of ESB more easily and accurately.It is shown that,the fault feature frequency of the ESB outer-race and its harmonics are surrounded by sidebands with a spacing equal to the modulating frequency of rotation frequency.The fault feature frequency of the ESB inner-race and its harmonics are surrounded by sidebands with a spacing equal to the modulating frequency of second-order rotation frequency.
作者
郭莹莹
赵学智
上官文斌
李伟光
GUO Yingying;ZHAO Xuezhi;SHANGGUAN Wenbin;LI Weiguang(School of Mechanical and Automotive Engineering,South China University of Technology,Guangzhou 510641)
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2019年第23期154-161,共8页
Journal of Mechanical Engineering
基金
广东省自然科学基金(2019A1515011780)
国家自然科学基金(51875216)
国家高技术研究发展计划(863计划，2015AA043005)资助项目
