考虑轴柔性的二级齿轮减速器振动噪声研究

Vibration and Noise Analysis for Two-Stage Gear Reducer Considering Shaft Flexibility

针对齿轮箱在实际运行过程中存在的轴系变形问题,提出了一种二级齿轮减速器在多源时变激励作用下振动噪声的计算方法。综合考虑齿轮、轴承时变刚度以及误差激励的影响,并引入二级齿轮相位关系,采用有限元法建立了计入轴柔性的二级直齿轮-轴-轴承系统耦合动力学模型。通过Newmark时域积分法求解系统动力学方程,得到各轴承动载荷,并分析了传动系统的固有特性及轴的静变形特征。采用有限元法对齿轮箱进行模态分析,提取箱体各阶固有频率与振型。以轴承频域动载荷为齿轮箱激励,利用模态叠加法计算得到齿轮箱的振动响应,并采用声学边界元法对齿轮箱的辐射噪声进行了计算。分析了轴柔性和转速对轴承动载荷与箱体辐射噪声的影响。仿真结果表明:计入轴柔性后,轴承动载荷波动幅值降低,激励频率成分也随之减少;在低频段200~900Hz与高频段1800Hz附近,箱体的主要共振模式发生改变,顶部场点噪声有所降低;随着转速的升高,激起了传动系统轴系弯曲振动模式,并引起传动系统振动幅值增大,且齿轮箱顶部场点噪声明显大于两侧场点噪声。研究结果可为减速器的减振降噪设计提供理论参考。

Aiming at the problem of shaft deformation in the actual operation of gearbox,a method for calculating the vibration and noise of a two-stage gear reducer under the multi-source time-varying excitation is proposed.Considering the effects of the time-varying stiffness of gear and bearing,a coupled dynamic model of the two-stage spur gear-shaft-bearing system considering shaft flexibility and phase relationship is developed.The bearing dynamic loads and inherent characteristics of gear transmission system are calculated and analyzed by the Newmark integration method.Taking the bearing dynamic loads as the excitation of gearbox,the modal analysis of the housing is carried out by finite element method,and the natural frequencies and mode shapes of the housing are obtained.The vibration response of the gearbox is calculated by the modal superposition method,and the radiation noise of the gearbox is calculated via acoustic boundary element method.The influences of shaft flexibility and input speed on the dynamic response and the radiation noise of the gearbox are analyzed.The results indicate that,the fluctuation amplitude of bearing dynamic load and excitation frequency components are reduced by taking into account the flexibility of shaft.At low frequencies(200-900 Hz)and near 1800 Hz,the dominant resonance mode shape of the gearbox is changed and noise is reduced.As the speed increases,the system undergoes the bending vibration of the shaft,which causes an increase in the vibration amplitude of the gear transmission system.The field point noise on the top of the gearbox is obviously greater than on the sides.The results may serve as theoretical reference for the design of vibration and noise reduction.