Undamped Dynamic Response Modelling of Four-Point Contact Slewing Bearings

Due to the mechanical behaviour of four-point contact slewing bearings, the vibrational response of mechanical systems that include these components is strongly conditioned by the stiffness and damping of the bearing joint itself. With a view to a forthcoming experimental correlation of these parameters, this work proposes a preliminary analytical model to calculate the undamped axial vibrational response of these bearings at locked rotation state. Results provided by the analytical model are compared with an ad-hoc developed finite element model in order to evaluate its validity. Results confirm that the inertial force of the ball and the damping effect of the ball-raceway frictional contact are negligible. It is concluded that the proposed analytical approach is promising due to its simplicity for both solving and post-processing in preparation for a forthcoming damping implementation and experimental correlation. Additionally, the main aspects to take care of in the finite element dynamic modelling of these components are pointed out.