变载荷激励下齿轮传动系统齿根裂纹故障动力学特性分析

ANALYSIS ON DYNAMIC CHARACTERISTICS OF TOOTH ROOT CRACK OF GEAR DRIVE SYSTEM UNDER VARIABLE LOAD EXCITATION

根据齿轮裂纹会引起齿轮系统的时变啮合刚度变化这一特性,建立了含齿根裂纹故障单级齿轮传动系统的四自由度动力学模型,对裂纹故障的非线性动力学机理进行了研究。采用变步长的四阶龙格—库塔法对齿轮裂纹故障进行仿真分析,运用时频分析方法研究了裂纹信号特征,为齿轮裂纹故障诊断提供了理论支持。在此基础上,分析了齿轮裂纹在变载荷激励下的动力学特性。分析表明:在变载荷激励下,齿轮振动波形图与变载荷激励变化趋势极其相似,裂纹的存在引起波形图上出现冲击现象并且啮合频率及其倍频附近出现边频带,边频带为故障齿轮的转频;变载荷激励下,低频的边频成分明显只与外载荷激励有关,与齿轮故障无关。

According to the characteristics that crack can cause changes in mesh stiffness,the four degree of freedom dynamic model of the single-stage gear transmission system with the gear crack fault is established and the nonlinear dynamic mechanism of crack fault is studied. The Runge-Kutta numerical method was used to simulate and analysis crack fault. The characteristics of the crack signal are studied by using the time-frequency analysis method,which provides a theoretical support for the gear crack fault diagnosis. On this basis,the dynamic characteristics of gear crack under variable load excitation are analyzed. Analysis shows that,under variable load excitation,the vibration wave forms are very similar to the variable load excitation; Cracks caused by the impact phenomenon on the waveform and meshing frequency and its harmonics appear sideband.Sideband spectrum of the meshing frequency is the rotating frequency of the fault gear; Under variable load excitation,the frequency components of the low frequency is related to the variable load excitation.