Influences Of Bearing Housing Geometrical Error On Dynamic Performance Of Rolling Bearing-Rotor System And Fatigue Life Of Rolling Bearing

The rotors supported by rolling bearings are widely used in mechanical equipment.The mechanical properties of the bearing are affected by the geometrical error of bearing housing,and the geometrical error of bearing housing also affect the dynamic performance of the rotor system and the life of the bearing.In this desertation,deep groove ball bearings and cylindrical roller bearings are taken as the research subjects,and the influences of bearing housing geometrical error on the dynamic performance of rotor system are studied.On this basis,the influences of bearing housing geometrical error on the fatigue life of deep groove ball bearings and cylindrical roller bearings are studied.The main research contents and achievements of this desertation include:by analyzing the deformation of the raceway and the rolling element of deep groove ball bearings and the deflection of the shaft,the model for calculating the additional load on the bearing with considering the bearing housing geometrical error is established.By introducing this model into the transfer matrix of rotor system,the transfer matrix calculation model of deep groove ball bearing-rotor system is established,which takes into account the influence of bearing housing geometrical error.The influences of housing nonconcentricity and housing deflection on stiffness coefficient of deep groove ball bearing and vibration performance of rotor system are studied.It is found that the stiffness coefficient of the bearing increases and the critical speed,amplitude and vibration mode of the rotor system change with the increase of the degree of misalignment and housing deflection angle.The load and displacement calculation model of cylindrical roller bearing is established with cosidering the bearing housing geometrical error.The additional force,torque and stiffness coefficients of the bearing caused by geometrical error of bearing housing are calculated.By introducing this calculation model into the transfer matrix of rotor system,the transfer matrix calculation model of cylindrical roller bearing-rotor system is established with considering the bearing housing geometrical error.The influences of nonconcentricity and deflection of bearing housing on stiffness coefficient of cylindrical roller bearing and vibration performance of rotor system are analyzed by an example.It is found that the first two critical speeds of the rotor system increase and the amplitude and mode of vibration of the rotor system change with the increase of the misalignment and housing deflection angle.The calculation model of ball load and contact stress between ball and raceway of deep groove ball bearing is established with considering ball diameter error,bearing housing geometrical error and vibration of deep groove ball bearing-rotor system.Based on the hypothesis of fatigue damage accumulation and fatigue curve formula,the influences of housing geometrical error,ball diameter error and vibration on the load and fatigue life of deep groove ball bearing rollers are analyzed.It is found that the geometrical error of bearing housing,the ball diameter error and vibration affect the load and contact stress of ball,and cause the fatigue life of the deep groove ball bearing decreases.A calculation model of roller load and contact stress between roller and raceway of cylindrical roller bearing is established,which can take into account the influences of roller diameter error,housing geometrical error and vibration.Based on the hypothesis of fatigue damage accumulation and fatigue curve formula,the influences of housing geometrical error,roller diameter error and vibration on the load and fatigue life of cylindrical roller bearing are analyzed by a specific example.It is found that the maximum load and the contact stress peak of the roller change and the fatigue life of the cylindrical roller bearing decreases with the increase of the misalignment,housing deflection angle,the roller diameter error and the rotor speed.The CUT-2 rotor vibration test bench is used to simulate the bearing housing nonconcentricity and deflection.Three groups of tests are carried out,including vibration test of rotor system without housing geometrical error,vibration test of rotor system with housing nonconcentricity and vibration test of rotor system with housing deflection.The variation trend of shaft deformation,amplitude and displacement of deep groove ball bearing-rotor system with housing nonconcentricity or deflection are tested.The variation trend of shaft deformation,amplitude and displacement of deep groove ball bearing-rotor system with housing geometrical error were tested.The vibration model of deep groove ball bearing-rotor system with bearing housing geometrical error established in this paper is validated by comparing the experimental results with the calculated results obtained by using the vibration model.The research contents and achievements of this desertation will be helpful for the further research of the mechanical,vibration properties and fatigue life of rolling bearings,and also helpful for the application of bearing and rotor in practice.