| Rotary parts are important parts of machinery industry.With the progress of science and technology,these parts are urgently required to develop towards high quality.Bearings are typical revolving parts,the main surface that bears the external load and the relative friction with the roller is the bearing raceway,the surface roughness and machining precision of the bearing raceway directly affect bearing performance and life.At present,the technology widely used in the finishing stage of bearing racewa y is "centerless rough grinding-centerless fine grinding-super finishing",for the conventional precision products,the qualified rate of the finished products is higher,but for high-precision bearings,such as P2 bearings,the yield rate of the finished products is lower.Improving the pass rate of precision bearing products is one of the key and difficult problems in the field of high grade bearing manufacturing in China,raising the precision of the raceway and improving the roughness of the raceway are one of the keys to solving this problem.Electrochemical superfine composite machining combines the two advantages of electrochemical machining and machining,quickly obtains good surface roughness.Recent studies have shown that this process can not only obtain high surface quality,but also improve the machining precision to some extent.This topic applies electrochemical superfine composite machining to bearing raceways,taking contour evolution rule and mechanism in electrochemical superfine composite machining and centerless grinding as the starting point that to explore high precision,high surface quality bearing raceway acquisition technology,it is of great theoretical and practical value to solve this problem.Research shows that the process conditions for forming high-precision parts with centerless grinding are harsh,however,multiple contour form can be formed under a wide range of process conditions.Electrochemical superfine composite machining is beneficial to improve the process characteristics of this type of contour error,This article proposes to obtain multiple contour through centerless grinding process parameters,electrochemical superfine composite machining can efficiently adjust the roughness and adjust the error of Multiple contour form,Use this technical feature to achieve high precision machining of raceways and to reduce the centerless grinding process conditions to form semi-finished products and improve the yield.In order to achieve the above goals,this paper takes the surface of the bearing outer raceway as an example to solve the problems related to the evolution of the contour form of centerless grinding and electrochemical superfine composite machining,and the main tasks are as follows:For the centerless grinding machining,conduct wheel size comparison tes and processing experiments of different pallet angles at different center heights,and analyze the influence of process parameters on Surface roughness,roundness and contour form,different contour form with high and low accuracy are obtained from this.The experimental results show that adjusting the process parameters can not only change the surface roughness and machining precision,but also change the profile of the workpiece,multiple contour within a wide range of machining conditions.For electrochemical superfine composite machining experiment with varying cathode coverage for different contour form.Through the discussion of the contour evolution rules,the contour rectification characteristics of Electrochemical superfine composite machining are obtained,which proves that electrochemical mechanical machining is conducive to the correction of multiple contour errors;The influence of cathode coverage on the surface roughness and roundness under different contours was analyzed,by expanding the cathode coverage,the difficulty of correcting low-frequency secondary contours by electrochemical superfine composite machining was solved.The results show that the formation of multiple contour in the stage of centerless grinding and the effective improvement of the roughness and contour error can be achieved by expanding the coverage of the cathode in the electrochemical superfinishing stage for bearing raceway finishing,the production efficiency and yield of the raceway can be greatly improved,providing the surface of the high quality rotary parts for the careless grinding,this is an effective machining method. |
