Study On High Precision Ball Processing Method Based On Uniform Envelope Principle Of Processing Trajectory

High-precision sphere is the key component of high-end ball bearings.Its geometric accuracy,surface quality and batch consistency affects the motion performance and working life of bearings and equipment performance.For the technical requirements of the high precision and high consistency for spherical rolling body machining,a process for variable turning curvature grinding method with single turntable is proposed under the principle of uniform distribution of sphere processing trajectory.The motion state of the sphere changes with the radius of curvature of the groove,thereby a full envelope processing spherical trajectory is gained,meanwhile,a high efficiency and high consistency sphere processing is achieved.The uniform distribution of processing trajectory is one of the necessary conditions for highprecision spherical forming.This paper focuses on the processing principle,the influence of the geometric parameters of the groove structure on the grinding uniformity,the ball-forming mechanism research and the material removal model,and the equipment development under the variable curvature groove grinding method.The main research works are as follows:Geometric kinematics model is constructed with the assumption of pure rolling motion and the theory of geometric kinematics,and the trajectory equation of the sphere is calculated.The influence of structural geometric parameters on machining path is studied,which are groove half angle,eccentricity,roller path diameter and groove spacing coefficient,and the optimized geometric parameters are obtained.The simulation of MATLAB software shows that the processing trajectory of the sphere surface can envelop the whole sphere completely under this processing method,and the shape of the processing track is multi-directional,which can ensure the high-precision processing of the sphere.The basic principle of sphere forming and the influence of loading system on the ball forming process are analyzed.The application of a fluid loading system is helpful to raise the amplification factor and improve the processing efficiency of the sphere.Combined with the Preston equation,the finite element software is used to analyze the force of the simulated multisphere system.The effects of sliding and rolling on material removal are studied,and the bearing steel material removal model under the modified curvature groove processing method is constructed.The diameter of the processed sphere and the load are gradually reduced as the diameter of the grooved disk increased.Eventually,the material removal rate of the sphere is reduced,and the material removal rate tended to be stable,and the waveform gradually converged.A horizontal variable curvature groove ball processing equipment is developed and the problem of ball accumulation is solved when the horizontal position of the ball outlet is higher than the entrance;At the same time,the length of the sphere processing path is steerable due to the application of online processing system of the sphere processing path length.The spindle is tested by vibration testing instrument,and its natural frequency is analyzed.On this basis,the strategy of control system is adjusted to avoid these points.In other words,the control strategy is changed to pass it when the speed reaches particular points.The single factor process experiment of the ball processing in the finishing stage is carried out on the self-developed single turntable variable curvature groove horizontal ball-making ball machine.According to the orthogonal experiment,the process parameters affected the sphere processing are optimized.The diameter variation after processing is 0.08μm,the spherical error is 0.078μm,and the surface roughness is 10 nm,which meets the standard of G3 ball.The research results show that the single-turn variable curvature groove grinding method based on the engraving principle of processing trajectory uniformity achieved the high precision and high consistency of the spherical processing.It has important theoretical significance and engineering application value for improving China’s high-end bearing manufacturing level and promoting the independent development of high-end equipment manufacturing industry.