含裂纹故障的齿轮系统动力学特性研究及其故障特征分析

摘要

考虑齿轮的时变啮合刚度、传动误差和轴承支撑刚度的影响,建立含齿根裂纹故障的齿轮系统多自由度力学模型,基于动力学方法对其故障机理进行研究.通过材料力学的方法计算齿轮在正常和含裂纹两种情况下的啮合刚度,对比两种刚度曲线的变化趋势,便于进行精确的动力学特性分析;对建立的模型求解系统的动态响应,结果表明当齿根存在裂纹时,其时域波形中会出现周期性的冲击现象,频谱中在啮合频率的基频及其倍频等地方形成一系列等间隔的边频谱线,其间隔大小等于故障齿轮的转频;这些边频成分幅值较低,能量分散且分布不均匀,在不同频带的幅值大小存在差异.针对上述特点,通过正交小波包方法对信号的频带进行分解,应用倒频谱分析各子频带信号的边频成分;结果表明,该方法能够有效的提高信号的信噪比,有助于识别和提取信号中由裂纹故障引起的边频成分.%A multi-DOF mechanical model of a gear system with crack fault was established to study its failure mechanism based on the dynamic method,considering effects of time-varying mesh stiffness,transmission error and bearing support stiffness.First of all,meshing stiffnesses of gears in two cases including normal condition and the one with crack fault were calculated for the accurate dynamic characteristics analysis.The results of the system's dynamic responses solved with the built dynamical model showed that there are some periodic impulses in time domain waveform,and there are some side frequencies equally spaced near the mesh fundamental frequency and its harmonic components,the interval between two side-frequencies is equal to the rotating frequency of the faulty gear;the amplitudes of side frequencies are lower and their energy is dispersive and not uniform,these amplitudes within different frequency bands are different.Aiming at the above mentioned features,the signal frequency band was decomposed with the orthogonal wavelet packet method and each sub-frequency band signal was analyzed using the cepstrum analysis method.The results showed that the proposed method can effectively improve the signal-to-noise ratio of signals,and make it easier to identify and extract side frequency components caused due to crack fault in signals to be detected.