Evolutionary regularity of dynamic characteristics for precision angular contact ball bearing under combined loads

Due to the inconformity of assembly stress and thermal expansion transfiguration in the internal components of shaft system，the precision angular contact ball bearing could be applied into the combined loads consisting of axial load，radial load，and torque，which affected both the dynamic characteristics of bearing and the service performance of precision shaft system.According to the relationship of interaction and relative position between the rolling element and bearing track，a five-degree-of-freedom quasi-static model considering the effects of centrifugal force，gyroscopic torque and other nonlinear factors was established，and the calculation model of bearing stiffness was improved by the principle of step-by-step search method.The evolutionary regularity of dynamic characteristics for precision angular contact ball bearings was investigated in combined loads.The results indicated that the axial load could decrease the difference between ball-inner raceway contact angle and ball-outer raceway contact angle，and suppress the stiffness softening caused by the increase of speed.When the torque and radial force were applied separately，the fluctuation range of contact angle and contact force increased，and the bearing stiffness along the direction of loads also increased，while the stiffness decreased perpendicularly to this direction.In the condition of combined loads，the torque would restrain the fluctuation of load distribution due to the radial load，and improve the loading capacity and service life of precision ball bearing.