| CNC machine tool is machine tool of the high-speed equipment manufacturingindustry. Due to CNC machine tool towards to the direction of high speed, highprecision, intelligent, flexible, green and so on, improve the precision and dynamics ofmain shaft bearing as the supporting transmission device of electric spindle systembecomes focus for research. For angular contact ball bearing of the spindle of CNCmachine tool, the loss of accuracy has replaced the fatigue failure as main form of theloss of bearing working performance. Therefore it is necessary to research accuracyand receptivity of high-speed bearing.In this article it studies accuracy and receptivity of high-speed angular contactball bearing. By the establishment of static model, researching the contact andinfluence between each parameter of bearing, the relationships of the load distributionand the change of contact angle; Based on the above researching of the motion state ofbearing, researching the relationships of the load distribution and the change of contactangle caused by the bearing of centrifugal expansion. Simultaneously considering theeffect of the rolling body size, number, the radius of curvature of the channel, load, theinitial contact angle, speed, preload method on bearing spin to roll ratio, friction torqueand stiffness, discussing the bearing life and wear theory, establishing bearingprecision life model, through the test surveying the effect of spin to roll ratio onbearing wear.The results show that: With the increase of bearing total curvature, the originalcontact Angle and axial clearance decreased; the original contact Angle and axialclearance increase with radial clearance. When considering centrifugal expansioneffect, outer contact angle and inner contact angle will be less than those withoutconsidering the action of centrifugal expansion, while the increasing of inner contactangle will be larger than that without consideration.The spin to roll ratio increase of rotational speed increasing; Increase the axial force can reduce the spin to roll ratio, radial force can increase the spin to roll ratio;under the same joint load, smaller contact angle of spin to roll ratio is small; largeinternal and external groove curvature radius cooperate can make the spin to roll ratiois lowest. The study of dynamics software RecurDyn about the cage mass centermotion law show that: The rotational speed has a greater influence on the cagecentroid movement, under different rotational speed increase the axial force can reducethe cage mass center pulse interval. The rotational speed has a greater influence onfriction torque, combined load and the original contact angle has a little influence onfriction torque. Under the high speed, big diameter roller, small configuration insideand outside of groove curvature radius, smaller original contact angle and increase thenumber of rolling body all conducive to increase the radial stiffness of the bearing;small diameter roller, internal and external roller groove curvature radius of alternateconfiguration, larger original contact Angle, increase the number and location ofpreloaded roller is conducive to increase the axial stiffness of the bearing.Bearing wear lead to bearing radial clearance increases, by allowable rotatingprecision value, it can get radial clearance incremental allowable value, according toradial clearance incremental get wear coefficient, after get the wear life, thus precisionbearing life model is established. Experimental analysis concluded that thetemperature of the bearing increase of rotational speed rising, at the same time,appropriately increase the axial force can reduce the bearing temperature, verified thecorrectness of the theoretical calculation. |
