Research On Structure And Manufacturing Errors Of Tilting Pad Thrust Bearings On Lubricating Characteristics And Longitudinal Vibration Of Shafting

The tilting pad thrust bearing is one of the important components in the marine power plant.Its lubrication characteristics not only affect the bearing capacity of the bearing,but also have an important impact on the longitudinal vibration of the shafting.A comprehensive analysis of it will help to improve the overall performance of the ship.The lubricating characteristics of tilting pad thrust bearings are taken as research objects in this paper,and the bearing lubrication model is established by means of hydrodynamics.The influence of different axle bush structure,shape error,installation error and speed change on lubrication characteristics and oil film stiffness of thrust bearing is analyzed.The influence of its lubricating properties and oil film rigidity.On this basis,the influence of tilting pad thrust bearing on the longitudinal vibration of shafting is studied.The details are as follows:(1)According to the knowledge of hydrodynamics,the hydrodynamic lubrication equation of thrust bearing is established,and solved by the finite difference method.At the same time,the calculation formula of oil film stiffness is obtained by the small disturbance method,and the corresponding calculation program is designed by MATLAB.(2)This paper analyzes the influence of the oil film thickness at the bearing pad support point,the bearing pad support position and the length width ratio of the bearing pad on the lubrication characteristic parameters such as the oil film pressure distribution,the bearing pad inclination angle,the bearing capacity and the friction force.It is found that a reasonable bearing pad structure is helpful to improve the lubrication performance of the bearing.(3)Through the construction of the mathematical model of the bearing lubrication characteristic parameters when the speed changes,the response of the lubrication characteristics of different structure bearings to the speed is analyzed,which provides the theoretical basis for the study of the working characteristics of different structure thrust bearings under dynamic conditions.(4)The shape of the lubrication surface is reconstructed through random functions and fractal functions,,and the influence of the waviness and roughness of the lubrication surface on the lubrication characteristics of the bearing is analyzed.(5)Through the transfer matrix method,the vibration model of the shafting is constructed,and the influence of the thrust bearing on the natural frequency of the shafting is analyzed under different bearing structure,shape error and installation error.At the same time,the response of thrust bearing and propeller to the longitudinal excitation of shafting at different rotating speeds is studied and analyzed.