多激励下某直升机传动系统动载特性

Dynamic characteristics under various excitations for a helicopter transmission system

针对由弧齿锥齿轮和行星轮系构成的直升机传动系统,构建了纯扭振动模型,采用集中参数法建立了齿侧间隙非线性动力学方程.通过有限元方法求得了时变啮合刚度,采用4-5阶变步长Runge-Kutta法对动力学方程进行了数值求解,借助动载系数、相图、Poincaré截面图、快速傅里叶变换频谱图等分析手段,研究了传动系统在时变啮合刚度、齿侧间隙、综合传动误差、外载荷等多种激励作用下系统的动载特性.结果表明啮合刚度对传动系统的影响最大,动载系数最大值为1.5;齿侧间隙对系统响应特性的影响是有限的;啮合误差在一定程度上抑制了齿轮系统的振动;外载荷波动对不同速级的影响不同,动载系数最大值发生在并车传动.

For a helicopter transmission system which consists of spiral bevel gears and planetary gear train,the purely torsional vibration model was established,and the non-linear dynamical equations containing backlash was built using the lumped-parameter method.Through the finite element method,the time-varying mesh stiffness was obtained,and the dynamical equations were solved by the 4-5order Runge-Kutta algorithm with variable time step;by means of dynamic load coefficient,phase plane plots,Poincarémaps and fast Fourier transform spectra,the dynamic characteristics of transmission system were studied under various excitations of the time-varying mesh stiffness,backlash,general transmission errors and external load.The results show that mesh stiffness has the greatest effect on the transmission system,with the maximum dynamic load coefficient of 1.5;backlash has a limited effect on the response characteristics;to some extent,mesh errors can suppress the vibration of the gear system;external load fluctuation has various effects on different speed stages,and the maximum dynamic load coefficient is stemmed from the combined drive gears.