中文摘要：

为揭示NGW型直齿行星传动的自由振动特性，在系杆随动参考坐标系下建立该型传动的平移一扭转耦合动力学模型模型设定系统中每个构件均拥有3自由度，并计入各构件的支承刚度、轮齿时变啮合刚度及陀螺效应等影响N素通过分析各构件间的相对位移关系，推导出系统的运动微分方程，进而求解其特征值问题，即可获知系统的固有频率和相应振型．依照传动系统的运动特征，可将NGW型直齿行星传动的自由振动分为3种典型振动模式，即扭转振动模式、平移振动模式和行星轮振动模式比较本模型与前人模型的仿真结果发现，两种模型所得的系统各阶固有频率相同．但其中心构件平移振动模式所对应的系统振型向量存在较大差异由于更正了前人模型中的推导错误，现有模型能更为准确地反映系统的自由振动特性．

英文摘要：

A translational-rotational-coupling dynamic model has been developed in the carrier-attached coordinate system to investigate the free vibration characteristics of NGW spur planetary gear set. The proposed model admits three degrees-of- freedom for each component and includes the key factors affecting planetary gears vibration such as component bearing stiffness,time-varying mesh stiffness and gyroscopic effect. Through analysis of the displacement relationship between different components,differential equations of the system have been derived,and the natural frequencies and vibration modes of the planetary gear set have been obtained through solution of the associated eigenvalue problem. Based on the unique properties of the transmission system,the vibration modes of NGW spur planetary gear set can be classified into three categories, i.e., rotational mode ,translational mode, and planet mode. Comparison between the proposed and previous models indicates that the two models have the same natural frequencies but different mode shapes. As the deductive errors in the previous studies have been corrected,the proposed dynamic model can reveal the free vibration characteristics of the planetary gear system more accurately.