Research On Asymmetric Cold Rolling Forming Technology Of High Speed Railway Bearing Inner Ring

Cold ring rolling technology is a kind of cold forming process,which can make plastic deformation of the ring parts at room temperature by the extrusion action of the cold rolling machine.Because of its advantages of saving materials,high precision of processing quality and good stability,cold ring rolling technology has been widely used in the production and operation of small and medium-sized bearing rings and wheels in various fields such as automobiles,trains,aerospace and so on.In recent years,the cold rolling technology of high speed bearing rings and other special-shaped section has a certain development,but most researches focus on the symmetric cold rolling,and there are few researches on asymmetric cold rolling.The finite element model of high speed railway bearing inner ring under asymmetric cold ring rolling process has been established through ABAQUS software in this pager.The influence of three kinds of mandrel feed modes on the force parameters during cold rolling is simulated and analyzed,which finds that the effect stepped reducer feed mode is the best.The results are obtained by single factor method that rolling force and torque shows an increasing relationship with initial feed rate of mandrel but a decreasing relationship with driven roll speed,and is limited by edging roll speed.By taking the wall thickness uniformity of finished rings as test index and using variance and range analysis method,the optimum feed parameters are obtained based on orthogonal test design method,that is,the initial feed rate of mandrel is 1.0 mm/s,the edging roll speed is 29 rad/s,the driven roll speed is 16 rad/s.Among them,the influence of the driven roll speed on the wall thickness uniformity is significant,while other factors have less impact,and there is no interaction between the factors.By analyzing the stress-strain distribution in each direction of biting compression stage,stable rolling stage and finishing circle stage in the cold rolling process,it is found that the distribution of stress and strain show a tendency to increase first and then decrease to be stable,which of the contact surface between the ring and the driven roll and mandrel are obviously larger than that of the core.The stress and strain is the largest and the plastic deformation is the most severe in the stable rolling stage.Simultaneously using the point tracking method and the velocity field simulation analysis,it is found that the metal flow direction is diversified during cold rolling,the metal flow of the surface of ring is strong and irregular,while the core distribution is more uniform.Through the research and analysis of the technical parameters and forming mechanism of high speed railway bearing inner ring under asymmetric cold ring rolling,it improves the theoretical system for the asymmetric cold rolling forming technology of the large and complex shaped section ring,having important theoretical significance and application value for further research and localization of high speed railway bearings.