Theoretical And Experimental Investigation On The Characteristics Of Double-row Tapered Roller Bearings

Double row tapered roller bearing has double-row tapered rollers and compact structure,which can withstand large radial and axial composite load while working,and it is the key basic component of large mechanical equipment.At present,in the design and application of such bearing,the research on the interaction mechanism of various components in the bearing internal structure under larger load is not deep enough.The mechanical properties of the doublerow tapered roller bearing,especially the analysis theory and test technology of heat,deformation,stiffness,and vibration,have great deficiencies.In this dissertation,with the support of National Key R&D Program of China "Rolling bearing service performance evolution mechanism and digital design method" and Liaoning’s major special project "Heavy axle and heavy haul railway freight car bearing",the threedimensional thermal characteristics,local deformation characteristics,dynamic stiffness and vibration characteristics of double-row tapered roller bearings are deeply investigated via the combination of theoretical analysis and experimental research.It provides guidance for the design,analysis and test of this kind of bearings,and has important theoretical significance and engineering value.The main achievements are as follows:Based on the structural characteristics of double-row tapered roller bearings,a quasi-static model is established considering radial load,axial load,preload load,rotation speed and bending moment.The internal load distribution of the bearing under typical composite loads is obtained.On the basis of the grease-based rheological properties,the influence of different working conditions on the film thickness of grease is studied.A three-dimensional thermal analysis modeling method based on local heat generation is proposed,the heat distribution characteristics of the bearing under compound loads are obtained,and the influence of working conditions on the circumferential,axial and radial temperature distribution is revealed.The multi-point temperature measurement of the inner and outer rings of the bearing is innovatively realized,which verified the accuracy of the thermal analysis model.Based on elastic contact theory,and considering the influence of bearing mounting structure,a modeling method for structural deformation of double-row tapered roller bearing rings is proposed,and the influence of operating conditions on the deformation is obtained.The fiber Bragg grating(FBG)technology for measuring the strain of bearing ring is realized,and the temperature-strain decoupling method is introduced.The static and dynamic deformation of double row tapered roller bearings based on FBG are studied.The theoretical and experimental results are in good agreement.Considering the effect of grease film thickness,a stiffness calculation model of doublerow tapered roller bearings is established,and the influence rules of load parameters,structural parameters and lubrication parameters on the stiffness of double-row tapered bearings are obtained.The results show that under the combined load,the axial load increases,and the overall contact stiffness and dynamic stiffness of the double row tapered roller bearing will show a "jump" phenomenon that rises first,then decreases suddenly,and then continues to rise.When the contact angles of inner and outer raceway increase,the radial stiffness decreases while the axial stiffness increases.The special law of stiffness variation of this kind of bearing has guiding significance for bearing design.Experimental study on vibration measurement of non-faulty double-row tapered roller bearings under different loads and different speeds is conducted,and the time-domain and frequency-domain responses of the bearing are obtained.The results show that double-row tapered roller bearings are dominated by high-frequency and medium-frequency vibration;the radial load increases the bearing vibration amplitude and the distribution range of the vibration frequency amplitude increases;the vibration of double row tapered roller bearing tends to be stable with the increase of axial load.Through the research of this dissertation,the analysis methods for heat,deformation,stiffness and vibration of double-row tapered roller bearings are proposed,which breaks through the multi-point testing technology of bearings in harsh environments and confined spaces.The influence of structure,load,speed and lubrication parameters on the mechanical properties of double-row tapered roller bearings is revealed.The research results of this dissertation can provide theoretical support and technical guidance for the design,analysis and test of double-row tapered roller bearings.