Research On The Motion Mode Of High Precision Sphere With Variable-radius And Its Device Design

At present,most of the high accuracy ball bulk processing methods are probabilistic ball forming method,which has a lot of problems,such as poor batch consistency and so on.As a new method of precision lapping,the variable-radius groove ball processing method can change the motion attitude of the ball by changing the curvature of the groove raceway.Based on kinematics analysis of balls and simulation of variable-radius groove machining method,machining device for high precision ball variable-radius groove processing method was designed,which aid the foundation for production and application of variable-radius groove processing method for the ultimate realization.The main work of this paper includes the following aspects:1)Analyzed f the principle of variable-radius groove machining method.Based on the assumption of pure rolling motion,the geometric kinematics model of a single ball system was established on the basis of geometric kinematics.The machining process of spherical surface with variable-radius groove was analyzed by the single machining cycle.2)Simulation analyzed of different processing methods of variable curvature groove sphere machining method and variable curvature groove plate main parameters,using SD standard deviation each trajectory point density within the grid area for the processing of trajectory uniform quantitative evaluation index,which based on a quantitative evaluation method spherical machining locus homogeneity.Considering the complexity of single cycle processing after machining trajectory distribution characteristics and engineering to achieve the required machining device,selected single rotating shaft eccentric type to design the variable-radius groove precision ball circulation processing device of variable-radius groove ball processing.3)On the basis of the analysis of the requirement of high precision sphere machining device with variable-radius groove,a variable curvature groove ball cycle processing device was designed.The main device was composed of a machine body,spindle drive mechanism,tailstock pressure mechanism,machining ball counting system,electric control system etc.4)The orthogonal experiment was designed with the ball bearing steel as the processing object.Based on Taguchi method,the influence of grinding pressure,abrasive particle size,abrasive concentration on material removal rate,surface roughness and the sphericity error was analyzed.The experimental results showed that for the material removal rate,grinding pressure effect was most significant;for surface roughness,the abrasive particle size had the greatest influence,and the grinding pressure had the least influence;for t the sphericity error,the grinding pressure had the greatest influence,while the other factors had little effect.On the basis of the analysis of the optimization of grinding parameters,the optimization experiment was carried out.The average surface roughness of the bearing steel ball was 12 nm,and the sphericity error reached 0.112μm,which had reached the standard of G5 ball.