单齿裂纹行星轮系合成刚度的劣化特性

行星轮系由于结构复杂,其齿面损伤对系统动态特性的影响不易评估,因而为行星轮系的故障诊断带来很大障碍.以某NGW21型行星齿轮减速器为研究对象,在内齿圈固定的前提下,研究了健康轮系的刚度合成方法以及齿面损伤条件下的刚度劣化行为.采用能量法获得了行星轮与太阳轮和内齿圈单独啮合时的刚度分布曲线,进而基于轮系内部的运动关系和各行星轮之间的相位关系,建立了多点同时啮合工况下的轮系刚度合成方法.针对太阳轮、内齿圈分别存在不同深度裂纹的情况,探讨了裂纹齿轮与行星轮单独啮合时的刚度分布,并最终对同一行星轮参与的内、外啮合刚度进行了合成.结果表明:太阳轮裂纹引起的整体刚度劣化更为明显,将更显著地影响行星轮系的响应特性.

Synthetic Stiffness Degradation Behavior of Planetary Gear Set With Crack on Single Tooth

Because of the complicated structure of a planetary transmission system, the effect of gear damage on the dynamic characteristics is not easy to assess, which has become a main obstacle to the fault diagnosis of such a system. Based on the precondition that the inner ring gear is fixed, this paper studied the stiffness synthesis method of healthy NGW21 planetary gearbox and the stiffness degradation behaviors induced by gear surface defect. The meshing stiffness distribution curves of planet gear when engaging with sun gear and ring gear separately were obtained by potential energy principle, then the meshing stiffness synthesis method of multi-point meshing condition was established based on the inner kinetic relationship of the gearbox and phase relationship between the planets. For the case of sun gear and ring gear with crack of different depths, the meshing stiffness distribution of cracked gear meshing with planetary gear was discussed, and finally the stiffness synthesis of the internal and external meshing of the same planet gear was completed. The analysis results show that the crack of the sun gear has more obvious effects on stiffness degradation behaviors and will have significant influence on the system characteristics.