Research On Mechanism And Superfinishing Process Of Silicon Nitried Ceramic Ball Bearing Raceway

Bearing plays an extremely important role in aerospace,high grade CNC machine tools,high-speed engine and many other areas of sophisticated equipment.Bearing working performance directly affects the performance of high-end equipment.Engineering ceramic material such as silicon nitride ceramic material has many excellent properties such as high strength,wear resistance,corrosion resistance,etc.,making it an ideal choice for bearing materials.For the rolling bearing,the raceway is an important working surface of the bearing,and its surface quality and raceway shape accuracy directly affect the operation and service life of the ceramic ball bearing.Superfinishing can greatly improve raceway surface quality and raceway shape accuracy to a certain extent.Because silicon nitride ceramic material is a kind of hard and brittle material that is difficult to process,it is very important to seek the best superfinishing technology with high efficiency and low cost.In this paper,the research object is outer ring raceway of H7009C type silicon nitride ceramics,and the superfinishing removal mechanism and superfinishing processing technology of silicon nitride materials are analyzed to provide reference and guidance for actual production and processing.The research contents mainly include:(1)Brittle and plastic removal mechanism of silicon nitride ceramic materials were summarized.Through the indentation fracture mechanics model and the analysis of the maximum undeformed cutting thickness of silicon nitride material,and the contrast of raceway surface morphology before and after superfinishing,it is found that the raceway surface material is micro removed by oilstone.The removal form is mainly plastic removal,accompanied by a small amount of brittle removal.(2)The orthogonal experiment of ceramic ball bearing raceway was carried out.According to the test results,the effect of different superfinishing parameters on the surface roughness and raceway shape accuracy in different stages was analyzed and summarized.(3)Based on the effect of superfinishing parameters on raceway surface roughness and raceway shape accuracy,the reasonable superfinishing parameters under the existing test conditions were obtained as follows:Rough superfinishing stage:superfinishing time 6s,workpiece tangent speed 350m/min,oilstone pressure 0.9N/mm~2,long stroke swing velocity 1100 times/min,short trip oscillation velocity 2000 times/min.Refine superfinishing stage:superfinishing time 11s,workpiece tangent speed 825m/min,oilstone pressure 0.1N/mm~2,long stroke swing velocity 1000 times/min,short trip oscillation velocity 700 times/min.(4)Based on the finite element simulation analysis of the superfinishing of the raceway of silicon nitride ceramic ball bearing,the finite element model of the diamond oilstone swing cut superfinishing was established.By changing superfinishing parameters,the stress distribution on raceway surface after simulation was observed,and the effect of superfinishing parameters on raceway surface roughness and raceway shape accuracy was further analyzed by combining the results of orthogonal test.To sum up,this paper made a detailed study on the superfinishing process of outer ring raceway of silicon nitride ceramic ball bearing through experimental research and theoretical analysis.The effect of the superfinishing parameters on the quality of ceramic bearing raceway was analyzed,and the best combination of superfinishing parameters was obtained.