发动机轴承装配条件对支承刚度的影响

Support Stiffness Dependent on Aero-engine Bearing Assembly Conditions

为探索航空发动机轴承装配条件对支承刚度的影响,支撑发动机转子系统的动力学设计和整机振动控制,在动力学方程的基础上,建立了振动测试和理论计算相结合的支承刚度辨识方法,并以某型航空发动机的五号支点轴承为对象,试验研究了圆柱滚子轴承内、外环配合参数、锁紧螺母拧紧力矩等参数对支承刚度的影响规律。结果表明:建立的支承刚度辨识方法准确可行;轴承内、外环为过盈配合时,过盈量增大,支承刚度增大,支承刚度对锁紧螺母拧紧力矩不敏感;轴承内、外环为间隙配合时,转子出现非线性共振,支承刚度大幅度地随机跳动,不符合线性条件假设。设计时应合理考虑轴承内、外环配合参数,避免导致转子系统振动特性恶化。

In light of the influence of aero-engine bearing assembly conditions on support stiffness and provide support for dynamic design of aero-engine rotor system and wholeengine vibration control,the identification of the support stiffness by the vibration test data and theoretical calculation is derived based on kineticequations.Experiments are carried out to investigate the variation laws of the support radial stiffness which are changed with the inner and outer ring fit tolerance and the inner and outer ring lock nuts tightening torque of an aero-engine No.5 bearing.The results show that the identification method is correct and viable.When the inner or outer ring is interference fit,the magnitude of interference increases as the support stiffness increases.The support stiffness is insensitive to the inner and outer ring lock nuts tightening torque.When the inner or outer ring is clearance fit,nonlinear resonance appears on the rotor,the bearing stiffness fluctuates randomly and significantly,and is incompatible to the assumption of linear conditions.In short,the fit parameters of inner and outer rings should be selected reasonably in design,in order to avoid deterioration of rotor system vibration features.