不同支承结构下同转/对转中介轴承的刚度特性

Stiffness Characteristic of Co-Rotating/Counter-Rotating Inter-Shaft Bearing with Different Supporting Structures

关键词:  航空发动机  中介轴承  结构特征  装配条件  发动机工况  刚度特性

Key words:  Aero-engine  Inter-shaft bearing  Structure features  Assembly conditions  Engine operating conditions  Stiffness characteristic

摘要:

中介轴承是耦合双转子航空发动机的关键部件，为了探明中介支承结构特征、装配条件和发动机工况对中介轴承刚度特性的影响，建立了中介圆柱滚子轴承刚度特性分析模型。模型综合考虑了中介支承结构形式、轴承内外环相对旋转方向、内外环配合参数、内外环锁紧螺母拧紧力矩、轴承工作温度、发动机转速、径向载荷和弹性流体动力润滑等方面的影响，分析了某型机中介轴承的径向刚度随各参数的变化规律。结果表明，内外环配合参数和发动机工况对中介轴承的刚度影响较大，设计时应考虑刚度变化对转子系统动力学特性的影响；中介轴承刚度对锁紧螺母的拧紧力矩不敏感。另外，中介轴承刚度同中介支承结构形式及内外环的相对旋转方向密切相关，设计时应结合气动性能和结构动力学的要求合理选取，避免对发动机的可靠性造成不利影响。

Abstract:

Inter-shaft bearing is the key component of the coupled dual-rotor aero-engine. In order to investigate the influence of inter-shaft support structure features， assembly conditions and engine operating conditions on the stiffness characteristics of inter-shaft bearing， stiffness characteristic analysis models for inter-shaft cylindrical roller bearing were set up. In the models， the influence of the inter-shaft support structure style， the inner and outer ring relative rotational direction， fit tolerance， lock nuts tightening torque， the bearing operating temperature， the aero-engine rotating speed， the radial force and the elastohydrodynamic lubrication were considered. The variation laws of a certain type aero-engine inter-shaft bearing radial stiffness with the above parameters were analyzed. The results show that， the stiffness of the inter-shaft bearing was greatly affected by the inner and outer ring fit tolerance and the aero-engine operating mode. The influence of the bearing stiffness on the rotor dynamics of the engine rotor system should be paid attention during the design stage. The radial stiffness of the inter-shaft bearing was insensitive to the change of the inner and outer ring lock nut tightening torque. What’s more， the inter-shaft support structure style and the relative rotational direction of inner and outer ring were closely related to the inter-shaft bearing stiffness， and these factors should be reasonably chosen by taking the aerodynamic performance and structure dynamic requests into consideration， in order to avoid bringing adverse effects to the reliability of the engine.