基于动力学特性的多级行星齿轮传动系统故障机理研究

Multi-stage planetary gear trains(MPGT) are widely used in energy equipments, shield tunneling machines, helicopters, automobiles, etc., because of their advantages such as compactness, large reduction and high power density. According to the problem of low reliability and unclear fault mechanism of multi-stage planetary gearbox，the gear-rotor-bearing dynamic coupling model of MPGT is proposed by using lumped-parameter method in this project. The natural characteristics and dynamic responses of gears transmission system are analyzed under multi-source excitation including time-varying mesh stiffnesses, clearance, transmission error, variable load, etc. The vibration responses of the planetary gearbox are calculated based on the finite element and dynamic substructure method, and the influence rule of dynamic parameters on system vibration will be revealed. Based on the analysis of influence of the typical fault on dynamic parameters, the nonlinear dynamic model is developed for MPGT with tooth crack, fracture, spalling failure. The mapping relation between the gear failure and system vibration is researched based on the bifurcation theory. Through test-bed experiment and theoretical analysis, the fault mechanism of multi-stage planetary gearbox will be elucidated based on dynamic analysis. There are some research results on three-stage PGT torsional dynamics for pre-project, and the further research will provide theoretical basis and technical support for reliability design and fault diagnosis of multi-stage planetary gear sets.

多级行星齿轮传动具有结构紧凑、传动比大、功率密度高等优点，在能源装备、盾构机、直升机、车辆传动等领域有广泛应用需求。本项目针对多级行星齿轮箱可靠性较低、故障机理不明等影响其工程应用的难点问题，运用集中参数法建立多级行星齿轮-转子-轴承耦合动力学模型，分析传动系统固有特性以及时变刚度、轮齿间隙、传动误差、变工况载荷等多源激励下的动态响应，基于有限元和动态子结构方法计算传动系统激励下的齿轮箱振动响应,揭示动态参数对系统振动的影响规律；分析行星轮系典型故障对动态参数的影响，建立含裂纹、断齿、剥落等故障的多级行星齿轮系统非线性动力学模型，基于分岔理论研究齿轮故障与系统振动响应的映射关系；结合理论研究，开展多级行星齿轮箱台架试验，从动力学角度阐明多级行星齿轮故障机理。本项目前期针对三级行星齿轮扭转动力学已取得一定的研究进展，进一步研究将为多级行星齿轮装置的可靠性设计与故障诊断提供理论依据和技术支持。

本项目针对复杂行星齿轮系统振动问题突出及故障率较高的工程背景，基于齿轮啮合理论、Lagrange方程和有限元等方法，构建行星架随动坐标系，提出有效的多级行星齿轮传动系统动力学建模方法。开展了系统固有特性分析，考虑内外部激励因素预测了系统动态响应，研究了传动系统参数对系统振动响应的影响。. 仿真分析了不同程度裂纹及断齿故障对齿轮时变啮合刚度的影响，建立了含故障的行星齿轮传动系统动力学模型，获得了故障齿轮模型的动力学响应。以背靠背形式搭建了75kW行星齿轮系统综合试验台，开展了正常与含齿根裂纹故障的行星齿轮系统动力学实验，获得了正常与故障齿轮箱的振动信号，对正常与故障齿轮振动的信号进行时域与频域的分析，对比理论仿真与实验的响应结果，验证了仿真模型的可行性及准确性。基于齿侧间隙、齿面摩擦力、时变啮合刚度、级间耦合等因素，建立了多级行星齿轮传动系统非线性动力学方程，获取了传动系统在激励频率作用下，分岔通往混沌道路的非线性振动特性，综合运用相图和Poincare截面对系统的混沌问题进行了阐述。. 综合考虑了齿轮啮合刚度、误差激励和振动传递路径的影响，分析了裂纹故障在系统振动响应中的故障特征，研究了行星齿轮系统在正常情况和含齿根裂纹故障时的频谱谱线分布特征，并通过试验信号验证了理论推导结果。基于参数优化Morlet小波的包络解调分析方法在行星齿轮系统故障特征分析的应用，利用小波熵优化得到小波的形状参数，实现母小波与信号故障特征的最佳匹配，利用小波系数峭度来优化小波的中心频率，确定最优的解调频带。根据优化的参数对齿轮振动信号进行包络解调分析，提出了有效的行星齿轮系统的故障特征提取方法。综合仿真和试验结果，探索了齿轮故障与系统振动响应的映射关系，从动力学角度初步阐明了多级行星齿轮的故障机理。研究工作及相关成果可为复杂齿轮传动系统的可靠性设计与故障诊断提供理论依据和技术支撑。