Superfinishing process control of raceway waviness in silicon nitride ceramic ball bearings
The waviness of bearing raceway is the main influencing factor on the vibration characteristics of bearings.In order to reduce the vibration level of silicon nitride ceramic ball bearings,a research on the superfinishing process control of silicon nitride ring raceway waviness was carried out.Superfinishing process experiments was conducted on silicon nitride ring raceway using a raceway superfinishing machine,the influence trend of superfinishing process parameters on raceway waviness was studied.A bearing calculation model for vibration characteristics was proposed considering raceway waviness,and the effectiveness of the cu-lation model was verified through vibration testing,the influence of raceway waviness was analyzed on bearing vibration character-istics.The results show that in superfinishing process,the raceway waviness first decreases and then increases with the increase of the tangential velocity of the workpiece,and then decreases and then increases with the increase of the oscillation frequency;the vibration level of the bearing gradually intensifies with the increase of raceway waviness.When the pressure of the oilstone is high,increasing the tangential velocity of the workpiece and oscillation frequency for rough machining results in a rapid decrease in raceway waviness.In superfinishing process,when the tangential velocity of the workpiece is 700~800 m/min,the oscillation frequency is 800~1 000 times/min,and the oilstone pressure is 0.2~0.4 N/m2,the surface waviness is ≤0.05 pim.The root mean square value of bearing vibration acceleration is≤2 m/s2,which meets the requirement of Z3 level bearing vibration accel-eration.