Analysis Of Mechanical Characteristics Of Double Row Tapered Roller Bearing For Main Reducer Of Vehicle Drive Axle

As one of the important supporting parts in mechanical transmission,bearings are widely used in the main reducer of vehicles.At present,two sets of single row tapered roller bearing plus spacer are widely used in the main reducer of vehicle drive axle and even in agricultural vehicles,but this structure has small bearing capacity,low damping capacity and inconvenient disassembly and assembly.When the rotating speed is high,there will be excessive vibration in the radial direction of the bearing,which will cause the rolling body to slip,skew and increase the friction with the raceway and the retaining edge,resulting in wear.On the one hand,it will lead to premature failure of the bearing,on the other hand,it will change the stiffness of the bearing,thus changing the vibration behavior of the bearing,directly affecting the efficiency,reliability and life of the main reducer of the vehicle.So at present,domestic and foreign enterprises have begun to try to use double row tapered roller bearing instead of single row tapered roller bearing plus spacer structure.From a pair of single row tapered roller bearings to a pair of double row tapered roller bearings,the law of internal contact mechanics and life change is not clear;for different support methods,the inherent characteristics of the main reducer gear shafting are not clear.Therefore,it is of great significance to analyze the mechanical properties of the double row tapered roller bearing after the optimization of the main reducer of the drive axle.In this paper,the mechanical properties of the bearing and the inherent characteristics of the gear shafting of the main reducer are studied.The main research contents are as follows:(1)The external load of the double row tapered roller bearing is obtained by the mechanical analysis of the main reducer of the locomotive,and the load distribution of the bearing is calculated based on the bearing theory as the load boundary of the single row bearing analysis.On this basis,the contact analysis model of the double row tapered roller bearing in the maximum bearing area is established by using the software,and the rolling body and raceway under the external load are analyzed Finally,according to the contact theory,the validity of the contact analysis model of the double row tapered roller bearing is verified.(2)Based on the contact analysis model of the double row tapered roller bearing established by the finite element method,the influence of different load conditions onthe contact performance of the bearing is carried out.The results show that the rolling element has the effect of edge stress concentration under the condition of composite load,so it is necessary to carry out the shape modification analysis on the rolling element,compare the commonly used shape modification methods of the rolling element,and determine the most ideal roller shape under the rated condition It can effectively improve the stress concentration phenomenon when bearing load,thus improving the bearing life.(3)The analytical and finite element models of the stiffness of the double row tapered roller bearing are established respectively,and the accuracy of the stiffness calculation of the finite element model of the double row tapered roller bearing is verified by comparing the finite element model with the theoretical calculation results.On this basis,the influence of axial force and inner ring end clearance on radial stiffness is analyzed,and the influence rule of axial preload and inner ring end clearance parameters on radial stiffness is revealed,which provides reference for bearing design and installation.(4)Based on the finite element method,the structural dynamic model of the main reducer shaft system is established,and the inherent characteristics of the shaft system supported by double row tapered roller bearings are analyzed.According to the stiffness analysis of double row tapered roller bearing in Chapter 4,the influence of different axial force and inner ring end clearance on the inherent characteristics of the shaft system is studied.In this paper,the double row tapered roller bearing is taken as the research object,and the internal contact mechanical properties,the overall stiffness and the structural dynamic characteristics of gear shafting are studied.At the same time,the change laws of the bearing stiffness and the inherent characteristics of the shaft system under the axial preloading and the change of the clearance parameters are revealed.The research results of this paper provide the feasibility of replacing the single row tapered roller bearing with the double row tapered roller bearing,as well as the bearing optimization design and the selection of preloading conditions Theoretical support and technical reference are of great significance.