考虑结构柔性的行星轮系耦合振动特性研究

Coupling Vibration Analysis for Planetary Gear System Considering Flexible Structure

针对传统集中质量法精度不高和大规模有限元模型计算量大、后处理困难的问题,在轴系单元法基础上提出一种针对行星轮系耦合振动分析建模方法。根据行星轮系结构特点,将行星轮系中各种构件分为简单轴系单元、行星架轴系单元及齿圈轴系单元等轴系模型,建立不同类型的行星轮系耦合动力学模型。研究结果表明,考虑结构柔性后,在低速阶段动态啮合力偏差与集中质量法求解结果基本相同,但随着转速增加,动态啮合力偏差与系统各阶共振频率均略有降低;而同一转速下,动态啮合力偏差随着齿圈厚度增大逐渐增加,但其变化量呈逐渐减小趋势。在所有结构中,轴的柔性化对振动影响最大,而行星架柔性对振动影响最小;各级齿轮副啮频相互耦合共同成为系统激励频率,而高速级啮频为最主要激励频率;振动能量不仅沿功率流方向传递,同样也会逆功率流方向传递。

Aimed at the problems of lower calculation accuracy of lumped mass method and large-scale computing, difficult post processing of finite element model, a novel coupling vibration analysis method for multistage planetary＇gear system is presented. The various components in planetary gear system are divided into three shaft models, which are simple shaft unit, planet cartier shaft unit and ring gear shaft unit, according to the structure characteristics of planetary gear system. Different types coupling dynamics model are established for planetary gear system. The results indicate that, the dynamic meshing force deviations obtained by shafting element method are almost same as that by the lumped mass method under the circumstance of lower rotation speed, But the dynamic meshing force and the resonance frequencies are both slightly lower with the increasing of speed. For a same input speed, the dynamic meshing force deviation is increasing with the thickness of ring gear, but the change tendency of the quantity is gradually decreasing. In all flexible structures, flexible shaft has a largest influence and planet carrier has a minimal impact to the vibration of the system. The gear meshing frequency in multi-stage planetary gear system are coupled with each other and become the excitation frequency of the system, and the mesh frequency of high speed stage is main excitation frequency of system. The vibration energy of the system is not only transmitted along the power flow direction but also reverse the direction of power flow transmission.