Stability Research And Simulation Of Shoe Centerless Grinding System For Bearing Rings

Centerless grinding is a precise machining method for rotary parts,which plays an important role in the production of bearing rings.With the development of precise manufacturing and military industry,the requirements of bearing performance and service life are higher and higher,and the machining accuracy of centerless grinding is higher too.In centerless grinding process,the motion and roundness of workpiece are very complex.The special positioning mode and driving mode of workpiece determine that the motion and roundness of workpiece are affected by a variety of process parameters.Shoe centerless grinding is an advanced form of centerless grinding,which has higher machining accuracy than guide wheel centerless grinding.At present,the domestic research on supporting centerless grinding theory is insufficient.In actual processing,it depends on the operation experience of workers,and the machining accuracy is uncertain.When the process parameters are unreasonable,it may even lead to safety accidents.In order to further improve the machining accuracy of the supported centerless grinding,it is necessary to deeply analyze the movement force of the workpiece in the process of the supported centerless grinding,and study the rounding mechanism of the supported centerless grinding.In this paper,the supporting centerless grinding is studied.Firstly,the dynamic analysis of the workpiece in the process of machining is carried out,and the stability conditions of the workpiece are deduced when starting and grinding force is applied.The friction model of the contact surface of the magnetic pole workpiece is established,and the resultant force and resultant moment of the magnetic pole under different rotating speeds are obtained,and the rationality of the friction model is verified by using extreme cases.On this basis,the matlab program is designed to determine the stable rotation speed of the workpiece driven by the magnetic pole under the process parameters,and the starting conditions of the workpiece and the hysteresis of the stable rotation speed are explained.The torque of workpiece under normal grinding force is solved,and the critical normal cutting force which is not the phenomenon of workpiece spinning is obtained,which provides theoretical reference for practical machining.In the work of rounding stability,aiming at the positioning form of support centerless grinding,the formulas of positioning error and composite error are derived,the geometric and static rounding stability models are established,and the rounding stability region maps under different harmonic orders are drawn.Based on the synthetic error formula and considering the factors of grinding residual coefficient,the MATLAB centerless grinding simulation system is designed.The roundness error of workpiece during machining process is evaluated by using the least square circle method,and the roundness error curve of workpiece with the number of machining cycles is obtained.The influence of grinding residual coefficient on the roundness effect of workpiece is discussed.Finally,the support structure of support centerless grinding is simplified,and modal analysis is carried out by using ABAQUS finite element simulation software.The modal frequency which has great influence on workpiece positioning in grinding direction is obtained,and the influence of bolt prestress change and base structure on vibration frequency is discussed.