| Water-lubricated rubber bearings have the advantages of clean,high cooling efficiency,wear resistance,silt resistance,reducing vibration and noise,etc.It has been widely used in ships,water turbines and other devices in recent years.The lubrication characteristics of water-lubricated rubber bearings is more complex than that of traditional oil-lubricated bearings.This is because low viscosity of water,diversified grooves,small elastic modulus of rubber lining.In this paper,the lubrication characteristics of water-lubricated rubber bearing under low speed and heavy load were studied from several aspects,such as the stability of bearing system,the bearing lubrication state,water-film pressure,etc.The main research work is as follows:(1)Based on hydrodynamic pressure lubrication,fluid-structure coupling and lubrication state theory,a mathematical model of water film pressure was deduced.The mathematical expressions of bearing characteristic parameters were obtained.Combined with the actual bearing parameters,the flow state of the lubricating medium was determined.(2)The internal flow field characteristics of water lubricated bearings were studied.The geometric model of water lubricated bearing fluid domain was established and the mesh was divided by sweep method.The software is set according to the actual parameters.The internal flow field of bearing was simulated.The speed,eccentricity and groove shape affect the water film pressure distribution is analyzed.The results indicate that the speed and groove shape have the largest influence of the water film pressure and fluid velocity,while the eccentricity has the least effect.(3)The solid domain geometric model of water-lubricated bearing was established.The steady-state two-way fluid-structure coupling numerical simulation is carried out.The influence of pressure of offer water on water film pressure distribution,water film bearing capacity,Equivalent stress and bearing bush deformation is analyzed.The results indicate that the water film maximum pressure increases,the water film bearing capacity decreases,the maximum Equivalent stress of the bearing increases,and the maximum deformation of the bearing bush increases with the increase of water supply pressure.(4)A wired and wireless test system of lubrication characteristics of water-lubricated bearings was constructed.The lubrication characteristics of water-lubricated rubber bearing with concave surface of ten grooves were studied under low speed and heavy load conditions(100～1100r/min and 0～1200N loading force).It includes system stability,lubrication state and water film pressure test.The wired test system is used to test the stability and lubrication status of the system.Wireless test system is used to test the water film pressure.The system stability test is to test and analyze the axis trajectory of water-lubricated shafting system under multiple working conditions.The wavelet threshold denoising algorithm is used to purify the axis trajectory.The distribution law of axis trajectory under different working conditions is analyzed.Bearing system stability is judged,the operating state of the bearing system is determined.Bearing lubrication state test is to obtain the change law of friction coefficient with speed and load.The friction characteristics of the bearings are analyzed.Streibeck curves are plotted,and bearing lubrication state is determined.Finally,based on the Zig Bee transmission technology,multi-condition test of water film pressure was carried out.The distribution law of water film pressure under different working conditions is analyzed and compared with the simulation results.The results show that water lubricated bearing is in mixed lubrication state under low speed and heavy load.The maximum water film pressure appears on the lath where the minimum clearance of the bearing. |
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