Abstract:In order to research the effect of natural frequency and vibration frequency of pad on stiffness of tiltingpad bearing,lubrication and dynamic coupling model based on long bearing theory was established to solve natural frequency and frequencyvariation stiffness of pad in tilting pad thrust bearing.Analytical solution of this lubrication model and formulae of frequencyvariation dynamic characteristics were deduced,and the influence of load,pivot coefficient (Ratio of the distance between oil inlet and pivot to the pad length),rotational inertia and other structural parameters on natural frequency and frequencyvariation stiffness were analyzed through example calculation.The results show that vibration natural frequency of tilting pad is codetermined by inertia,stiffness and damping of oil film.When the vibration frequency of pad is close to its natural frequency,frequencyvariation stiffness of bearing presents negative value even with positive and negative infinite.The situation that vibration frequency is close to its natural frequency is easily appeared for the pad of light load (unloaded pad for an example),which will cause resonance phenomenon.In order to ensure vibration frequency is greater than natural frequency of pad to produce high stiffness,it is necessary to take natural frequency and frequencyvariation stiffness into consideration to design pivot coefficient and inertia of unloaded pads in design of the tilting pad bearings.