Research On The Mechanical Characteristics Of Aero-engine Ball And Roller Bearings

Rolling bearings are one of the most important components in mechanical rotating systems as a basis part to support shaft and transfer loads.Rolling bearings are widely used in numerous rotating machines,ranging from the motor of toy cars to the aero-engine in aircraft.Compared with other applications,the performance of rolling bearings for aero-engines need to be better,because rolling bearings in aero-engine work in the harsh conditions of high speed and heavy load for a long time.As a consequence,to improve the working performance of aero-engine,it is of great significance to understand and investigate the mechanical characteristics of aerial rolling bearings.In this paper,the common high-speed ball bearing and cylindrical roller bearing in aero-engine are taken as the research object.Then,the mathematical analysis models are established to study the mechanical characteristics of aerial high-speed rolling bearings,such as displacement,stiffness,load distribution and fatigue life.Finally,provides a direction for the independent design and manufacturing of rolling bearings in China.The main research contents of this paper are as follows:(1)A quasi-static model is established to study the mechanical characteristics of aerial ball and roller bearings based on Hertz elastic contact theory.The influence of the position change of the rolling elements on the mechanical properties of rolling bearings are considered in this model.On this basis,the vibration problem and stiffness fluctuation caused by the change of rolling element position are emphatically explored.Some conclusions can be drawn from the results: The changes of the positions of the rolling element relative to the inner and outer raceways can lead to obvious vibration and stiffness fluctuation of the rolling bearing.In addition,a larger radial clearance and less rolling elements can greatly aggravate the vibration.(2)A four degree-of-freedom quasi-static model of aerial cylindrical roller bearing is established.This model considers the rotation effect and some potential error sources such as axial offset,angular misalignment and radial clearance.The mechanical characteristics of aerial cylindrical roller bearing under combined load are studied.Some conclusions can be drawn from the results: with the increase of radial load,the radial displacement and the stiffness of the cylindrical roller bearing increases.However,the fatigue life of the cylindrical roller bearing decreases.Compared with the external loads,the rotational speed has less effect on the stiffness of the cylindrical roller bearing.Besides,the basic structural parameters of the bearings also have a great impact on the mechanical characteristics of the rolling bearings.In practical application,it should be designed according to actual needs.(3)Based on the performance test experimental system of cylindrical roller bearing,the bearing stiffness test experiment is carried out.The experimental results are compared with the theoretical analysis results to verify the accuracy of the theoretical calculation.The results show that the results obtained by the quasi-static model are basically consistent with the experimental results,which proves the accuracy of the theoretical analysis in this paper.