Research On Precision Grinding Of Full Ceramic Ball Bearing Ring Raceway And Grinding Wheel Dressing

The raceway of full ceramic ball bearing ring is an important working face for bearing to bear load.The poor raceway shape error and surface quality affect the assembly tightness of raceway and balls,resulting in low rotation accuracy of full ceramic ball bearing and large vibration and noise during service.In the process of grinding,the raceway shape error and surface quality are closely related to grinding parameters such as grinding depth,grinding wheel linear speed,workpiece feed speed and so on.In addition,the contour accuracy of the diamond circular arc grinding wheel gradually decrease,which directly affect the raceway shape error;At the same time,the grinding wheel appear wear and air hole blockage during grinding,which seriously reduce the grinding performance of the grinding wheel and greatly affect the surface quality of the raceway.Therefore,in the process of ceramic bearing ring raceway grinding,the grinding process parameters and diamond arc grinding wheel dressing must be studied deeply.In this thesis,the influence of grinding parameters on the raceway shape error and surface quality,the process optimization and dressing of resin bonded diamond arc grinding wheel with diamond disc are studied.The main research contents are as follows.（1）This thesis summarizes the evaluation index of circular arc raceway of full ceramic ball bearing,analyzes the main causes of raceway shape error in grinding raceway,and compares different raceway grinding methods;Theoretically analyzes advanced ceramic grinding,establishes the relationship between grinding contact arc length and grinding depth,calculates the linear velocity of circular arc contour surface of grinding wheel and many contact points of workpiece,and covers the surface defects of ceramic grinding.（2）The single factor experiment and orthogonal experiment of zirconia ceramic raceway grinding are carried out.The influence of grinding parameters on raceway shape error and surface roughness of zirconia ceramic is obtained,and the optimal grinding parameters are determined.The experimental results show that the raceway shape error P_t increases with the increase of grinding depth and grinding wheel linear speed,decreases first and then increases with the increase of workpiece feed speed;The surface roughness R_a,R_3y and R_z decrease with the increase of grinding depth,grinding wheel linear speed and workpiece feed speed;The optimized process parameters are as follows:grinding depth is 5μm,grinding wheel linear speed is 40 m/s,and workpiece feed speed is 1000 mm/min;The effects of grinding wheel feed rate and raceway profile on the workpiece surface profile are analyzed.（3）The dressing experiment of diamond arc grinding wheel is carried out.After dressing,resin bonded diamond circular arc grinding wheel is used to grind the inner raceway of bearing,and the contour of circular arc grinding wheel is reflected on the inner raceway of bearing.The surface morphology of the outer edge of the grinding wheel before and after dressing is observed and compared.Through dressing,the surface of the grinding wheel is glossy,and the number of diamond grains exposed on the surface increase obviously.In the local part of the surface,some diamond grains are broken,forming a new cutting edge,or falling off,expand the space of air hole.After sharpening,the surface morphology of whetstone is observed,the exposed height of abrasive grains is increased,the surface morphology of grinding wheel is improved,and the grinding performance of arc grinding wheel is improved.（4）Based on the grinding test of inner ring raceway of full ceramic ball bearing,the raceway of bearing inner ring is grinded with resin bonded diamond circular arc grinding wheel after dressing,and the contour of the outer edge of circular arc grinding wheel is reflected on the raceway of bearing inner ring.The influence of dressing depth on the raceway shape error is studied;the raceway shape error and surface roughness of the raceway before and after dressing are detected and compared.After dressing,the average value of raceway shape error P_t is 2.7990μm,reduced by 51.93%,and the average value of surface roughness R_a is 0.2389μm,reduced by 24.89%.The dressing effect of arc grinding wheel is verified.By analyzing the test curve of raceway shape error,whether there is serious shape distortion defect in the corresponding position of the outer edge contour of grinding wheel is explored.Based on a large number of zirconia ceramic raceway grinding experiments,the effects of grinding process parameters on raceway shape error and surface quality are studied,and the optimal grinding process parameters are determined.Through the dressing test of resin based diamond arc grinding wheel,the contour accuracy of the grinding wheel is improved;the raceway shape error is reduced;The surface morphology of the grinding wheel is improved,and the grinding performance and quality of the raceway surface are improved.The research results of this thesis provide theoretical basis and scientific guidance for precision grinding of full ceramic ball bearing ring raceway.