Research On Machining Method Of Precision Sphere And Design Of Key Parts Of Machining System

The current ball grinding methods can not meet the requirements of high precision,high consistency and mass production.Based on the variable curvature groove lapping method,a multi helix variable radius circular lapping method is proposed.By changing the equidistant helix on the groove disc from one to multiple,the inclined circular disc mechanism can be used to improve the batch size of single processing.In this thesis,the motion principle of a single sphere and the geometric parameters of the corresponding groove disc in the multi helix variable radius groove machining method are studied,and the key parts of the related machine tools are designed and analyzed.The main work and conclusions are as follows:(1)This thesis briefly introduces the basic principle of multi helix variable curvature groove machining,and finally determines the eccentric variable curvature groove machining method of vertical single turntable groove through analysis.Taking any spiral curve in the grooved disk as the research object,the geometric kinematics model of a single sphere under ideal conditions is established by the velocity vector analysis method.The grinding trajectory of a single sphere is simulated by MATLAB software.The results show that the grinding trajectory formed by the three contact points can cover the whole sphere evenly and is multi-directional.(2)An evaluation method of grinding trajectory uniformity based on SD value of trajectory point standard deviation is established.The smaller the standard deviation is,the more uniform the machining trajectory is.The grinding trace lines of three common machining methods are simulated and analyzed,and the advantages of multi helix variable curvature groove machining method are verified.The influence of different spiral lines on the grinding consistency of the ball blank is analyzed.The geometric parameters of the groove are simulated and analyzed by single factor analysis method.The results show that the following are the following aspects: When the eccentricity is 3,the groove half angle is 45°,the spacing coefficient is 2.5,and the polar diameter of raceway is 45,the SD value of standard deviation reaches the minimum.(3)In this thesis,a new type of inclined disc plane is designed.By setting several equal spacing grooves on the circular plate of the upper disc,the rolling friction and collision friction between workpieces in the disc are reduced.The structure and operation power of the disc are calculated.The structure optimization of the bed,pressure plate and beam components which affect the machining accuracy of the machine tool is carried out.Through the topology optimization analysis of the bed,the optimal distribution of the material is obtained,on the basis of enhancing the stiffness,the mass of the bed is reduced;The optimal eccentricity of the pressure plate is obtained by response surface method,which makes the force distribution of the pressure plate more uniform and improves the working stability;In order to improve the static and dynamic stiffness of the beam,the most appropriate rib shape and side wall thickness are selected through comparative analysis.