某直升机主减传动系统振动能量传递特性研究

Vibration energy transfer characteristics of main reducer transmission system of a helicopter

基于超单元方法和节点有限元法建立考虑轴系柔性和机匣柔性的齿轮-转子-机匣耦合系统动力学模型,推导了各类齿轮副的啮合关系,以直升机主减速器为研究对象,通过振动响应试验验证了模型的有效性。从振动能量的角度研究耦合和不耦合柔性机匣两种情况下,齿轮副作为振动激励源时系统模型中产生的多级齿轮激励现象和作为传递结构时对振动能量的传递特性。研究结果表明:耦合机匣后,各级齿轮振动能量贡献占比的极值点数量减少,与目标点相邻的齿轮激励源在该节点处振动能量贡献占比整体上升,不相邻的齿轮激励源在该节点处能量贡献占比整体下降;齿轮啮合刚度和啮合阻尼比的增加会提高齿轮副对振动能量的传递能力,啮合误差的增加会降低其对振动能量的传递能力,而耦合柔性机匣会放大齿轮啮合特性对其振动能量传递能力的影响。

The dynamic model of a gear-rotor-casing coupled system considering shafting and casing flexibility was established based on the super element method and node finite element method.Meshing relations of various types of gear pairs were derived.Taking the main reducer of a helicopter as the study object,vibration response tests were used to verify the effectiveness of the model.From the perspective of vibration energy,the multi-stage gear excitation phenomenon generated in the system model when gear pair was taken as a vibration excitation source and transmission characteristics of vibration energy when gear pair was used as a transmission structure were studied under two conditions of flexible casing involving coupling and uncoupling.The results showed that after casing involving coupling,the extreme point number of vibration energy contribution rates of gears of various stages decreases,the vibration energy contribution of gear excitation source near the target point to this point generally increases,whilethat of the non-adjacent gear excitation source to the target point generally decreases;increase in gear meshing stiffness and meshing damping ratio can increase the contribution of gear pairs to vibration energy;increase in meshing error can reduce the transmission capacity of vibration energy,while the coupled flexible casing can enlarge effects of gear meshing characteristics on gear pairs’vibration energy transmission capacity.