Characterization of the dynamic behavior of a linear guideway mechanism

This study was aimed to develop an algorithm to accurately predict the nonlinear contact characteristics at the rolling interface in a linear guide mechanism. Generally, such a contact characteristic between ball and raceway was expected to vary with the loads acting on the mechanism and hence to affect its dynamic behavior. In order to enhance the efficiency of analysis, the contact stiffness in normal direction of contact interface were evaluated based on the Hertzian contact theory. By introducing the contact element with appropriate contact stiffness into the finite element model, we can investigate how the dynamic characteristics of a linear guide were affected by loading conditions. In analysis, two different contact statuses, 1-D point-to-point and surface-to-surface, were first assumed at the contact surface for comparison and the surface-to-surface contact model was validated as the one reflecting the real contact characteristics in reality. In further application of the proposed method, dynamic experiments on linear guide with various preload conditions were conducted by measuring their frequency spectrums here. Current results show that both of the two approaches predict the natural frequency to similar values, of which finite element method is a preferred option since it has taken into account of the influence of contact stiffness at the rolling interface between steel ball and raceway of linear guideway. Experimental results illustrate that the natural frequencies corresponding to different vibration modes indeed increase with the preload of the linear guide system, while such a variation in frequency has been shown being affected by the change of contact stiffness due to the preload.