Research On The Sphere-Shaping Mechanism 0f Rotated Dual-Plates Lapping Mode

Bearing is widely used in precision mechanism, and the bearing balls and ceramic balls are one of its major components. The precise bearing balls play the important role in precision engineering. Because of the limitation of sphere generation mechanism, low finishing efficiency and high cost, the traditional lapping technique of precise bearing balls can hardly meet the requirements of modern science and technology. To overcome limitations in traditional lapping process, a new type of high efficiency lapping method for high precision ball, Rotated Dual-Plates (RDP) lapping, is developed by our research center, which inherits the advantage of spin angle control lapping, so the lapping trace can be evenly distributed on the ball.In orde to quantificationally analyze the lapping uniform of RDP, the basic material removal rate of ball-plates'contact point is researched. Firstly the contact stress between the upper grinding plate and presion ball is calculated by finite element method, and the plane grinding experiments of bearing steel and Si3N4 materials are designed according to the contact stress. At last, the rules of two typical materials are obtained by the array of single factor grinding experiment, which provides the basis for lapping uniformity of simulation.In this thesis, the kinematics of the other lapping method is also analysised, and the motion equations of RDP lapping mode is obtained, according to the equations of motion equations of RDP lapping mode, the lapping trace is calculated, and the distribution of lapping trace on the ball is simulated by computer simulation. At last, for further quantificationally analyzing lapping uniform, the estimation methods of grid division on precision bearing ball are put forward, and the plane grinding experiments of bearing steel material removal rules is also applied to the simulation, so the lapping uniformity of balls can be well analysised. At last, the difference of RDP lapping mode and traditional v-grooves lapping method are compared, and some parameters of device which influence the lapping uniformity are also analysed.In order to verify the lapping uniform of the RDP lapping devices, the lapping uniform experiment of RDP lapping devices is done based on the sphericity of simulation. During the experiment, the material removal rate and sphericity are selected as the target of the evaluation, so the abave of grinding combination can be verified. It is shown that the precision ball can be lapped uniformly in RDP mode, and rotational speed and load are the chief influence factors on the lapping uniformity.By establishing of mechanisms of sphere error correction, ball sliding against plates and impaction between balls mode, the ball's mechanism of the RDP lapping mode and influence factors in the lapping are analysised in the end. The influence of material remova, the presion of device and lapping tools on sphere-shaping process is also discussed with theory analysis.