Stuck Fault Mechanism And Ultimate Load Analysis Of Bearings System In Air Rudder System

Rolling bearings are important mechanical basic components,which is widely used in various types of rotating system.As a kind of rolling bearings,deep groove ball bearings are mainly used to withstand the radial load,and can withstand some axial load.However,in the air rudder system of a new hypersonic vehicle,the deep groove ball bearings must withstand large moment load and stuck fault occurs.In this paper,it studies the mechanical transmission components of the air rudder system under large bending moment load,and mainly focus on the limit inclination angle between the inner and the outer ring of the deep groove ball bearings.Firstly,the contact stress between rolling elements and the inner and outer ring raceways of the deep groove ball bearing 61809 is solved by using the Hertz elastic contact theory.The reference value of the ultimate radial load that the deep groove ball bearing 61809 can withstand is 4kN.Then,based on the calculation formula of the ultimate inclination angle of the inner and outer rings of the rolling bearings and the relevant contents of the mechanical design manual,the theoretical value of the ultimate inclination angle of deep groove ball bearing 61809 inner and outer rings is calculated and converted into the ultimate displacement,which provides the reference standard for the finite element numerical simulation.Based on the above,the finite element numerical simulation of the ultimate inclination angle of the inner and outer rings of a single deep groove ball bearing 61809 has been carried out.The influence of friction coefficient,radial load and material on the ultimate inclination angle of the inner and outer rings of the bearing is mainly considered.The results show that the ultimate deflection displacemet of bearing is not affected by the friction coefficient and the radial load.When the stainless steel is used,the ultimate deflection displacement of the bearing is larger than that of the bearing steel.That is,the moment load of the bearing can withstand is smaller when the stainless steel material is applicated.At the same time,the ultimate displacement of single shaft and bearing seat is also analyzed.And then,the finite element numerical simulation analysis of the bearing system is carried out to study the influence of the structural assembly on the bearing to resiste the bending moment load,mainly considering the influence of the solid shaft,the hollow shaft,the number of bearings and the position of the load.The results show that the bearings system can greatly improve the capacity of the bearing to resist the bending moment load.The relative inclination angle of the inner and outer rings of the bearing is mainly determined by the flexural rigidity of the shaft rather than the bearing itself,that is,the root cause of the stuck fault of the control surface is that the flexural rigidity of the shaft is not enough.And,relatively speaking,the mechanical properties of the bearings system are not significantly improved with three bearings.The position of the load has an important influence on the ultimate load that the bearings system can withstand.The position of the load changes the magnitude of the bending moment load and the load distribution in the bearings system.When the distance of the load action point is large,the ultimate load which the bearings system can withstand is greatly reduced.Finally,according to the characteristics of the bearing system,the bearing system is optimized by moving the bearing 3 to the left and right and reinforcing the bearing seat 3 respectively.The results show that the ability of bearings system to withstand ultimate load can be significantly improved by moving the bearing 3 to the left.When the bearing 3 moves 5mm to the left,the ultimate load that the bearings system can withstand is increased by 41.11%.