A dynamic friction moment calculation method of an angular contact ball bearings

Abstract

Angular contact ball bearings (ACBs) are widely applied in various precision rotational systems due to the simple structure, high speed and high rotation accuracy. Most current works have analyzed the friction moment of ACBs under the assumption that the contacts in the contact zones are pure rolling. However, in actual applications, the balls and rings will be slipping relative to each other. Under high speed conditions, the relative slip in the contact zones are obvious. Moreover, the relative slip will have a manifest influence on the friction moment and the contact forces in the contact zones. Thus, it's unreasonable to assume the contacts in the contact zones are pure rolling under high speed conditions. This work proposed a dynamic friction moment calculating method for an ACB considering the skidding in the contact zones based on the quasi-dynamic model. In the model, the gyratory motion and relative slip in the contact zones are considered. The contact forces are obtained by the quasi-dynamic model. The sliding friction moments caused by the differential slip (DS), the rolling friction moments caused by EHL (elastohydrodynamic lubrication) rolling resistance, the rolling friction moments produced by the EMH (elastic material hysteresis) and viscous friction moments generated by the gas-oil mixture are calculated. Moreover, the sliding friction moment caused by the differential slip is calculated by the elastohydrodynamic lubrication theory. The friction moments computed by Palmgren method and the proposed method are analyzed to prove the accuracy of the proposed method. The influence of inner ring speed on the contact forces, contact angle and the ACB friction moment are studied. The results suggest that the proposed method can give a more accurate and effective way to calculate the ACB friction moments.