机体杆端轴承-密封单元的动力学特性

Dynamic Characteristic Analysis of Airframe Rod End Bearing-Sealing Unit

机体杆端轴承在往复摆动的过程中,密封圈磨损严重,导致润滑脂保持率低和轴承寿命短,影响飞机的飞行安全。针对这一问题,建立机体杆端轴承-密封单元系统的动力学模型,分析工况条件(摆动频率、摆动振幅及轴承腔内温度)对系统密封性能的影响以及密封单元参数(密封圈内径、密封圈厚度、橡胶材料硬度、金属骨架轴向尺寸、金属骨架内径)对轴承摩擦力矩的影响规律,结果表明:密封圈与轴承内圈的最大接触应力随轴承腔内温度升高而减小,随轴承摆动频率和摆动振幅增大而线性增大;机体杆端轴承的摩擦力矩随橡胶密封圈厚度和橡胶材料硬度的增大而增大,随金属骨架轴向尺寸和内径的增大而减小,随密封圈内径增大而产生波动,密封圈内径应小于9.5 mm以避免摩擦力矩急剧增大。结合分析结果对密封单元进行增效设计,密封特性及摩擦特性试验结果表明,增效设计后,密封单元的润滑脂保持率提升了17.3%,轴承启动力矩下降了21.6%。

During the reciprocating swing of airframe rod end bearing,the seal is worn seriously,resulting in low retention rate of grease and short life of the bearing,and affecting the flight safety of aircraft.To solve this problem,a dynamic model of airframe rod end bearing-sealing unit system is established,the influence of operating conditions(swing frequency,swing amplitude and bearing cavity temperature)on sealing performance of the system,as well as the influence of parameters for sealing unit(inner diameter of seal,thickness of seal,hardness of rubber material,axial size of metal skeleton,inner diameter of metal skeleton)on friction torque of the bearing are analyzed,the results show that the maximum contact stress between seal and inner ring of the bearing decreases with the increase of bearing cavity temperature,and increases linearly with the increase of swing frequency and swing amplitude of the bearing;the friction torque of the bearing increases with the increase of thickness of rubber seal and hardness of rubber material,and decreases with the increase of axial size and inner diameter of metal skeleton,and fluctuates with the increase of inner diameter of seal,the inner diameter of seal should being less than 9.5 mm to avoid a sharp increase in friction torque.The efficiency enhancement design of sealing unit is carried out based on analysis results,the test results of sealing and friction characteristics indicate that the retention rate of grease of sealing unit increases by 17.3%and the starting torque of the bearing decreases by 21.6%after efficiency enhancement design.