Study On Elastohydrodynamic Lubrication Characteristics Of Water-lubricated Rubber Bearings With The Complicated Structure

The water-lubricated rubber bearings are regarded as the object of study in this thesis.Based on the elastic deformation of rubber layer and the theory of elastohydrodynamic lubrication,the mathematical model of different forms of the bearings structures is established.The lubrication characteristics of water-lubricated rubber bearings with some complicated structures is analyzed on the numerical method,in which different parameters such as the mixed groove,the specific spiral-angle,and the length-diameter ratio,etc.The main contents and conclusions can be summarized as:(1)After considering the elastic deformation of the rubber layer,the mathematical model of the water-lubricated rubber bearings is established.Based on the finite volume method and the finite element method,the influence of the structure parameters on the lubrication characteristics is analyzed.The results show that the variation of the parameters mainly affects the lubrication characteristics of the bearings in pressure area of bearing.With the increase of the rotational speed,the continuity of the water film decreases and the stability of system decreases.The large length-diameter ratio has a great influence on the deformation of the rubber layer,the transmission speed of water film pressure is fast,and the water film is not continuous at the rear end of the bearing.With the increase of the eccentricity ratio,the deformation of the rubber layer only has a great influence on the pressure area of bearing,and the pressure gradient decays faster under the larger eccentricity ratio.The speed of the groove edge is greatly affected and affect the continuity of water film.(2)The effects of different groove structures on the elastic hydrodynamic lubrication characteristics of water-lubricated rubber bearings are discussed.Then,a kind of water-lubricated rubber bearings with the mixed-groove structure is designed by considering the requirements of lubrication conditions in different regions,which is analysed compared with other structures.The results show that the mixed-groove structure draws the advantages of different grooves.The T-typed groove is opened in the pressure area of bearing,and the water film pressure is small and the pressure capacity of bearing is improved.The V-typed groove is provided in the non-pressurized area of bearing,and the flow characteristic is improved.The distribution of the deformation of rubber layer,the water film pressure and the flow field are good in the whole performance.(3)A kind of water-lubricated rubber bearings with a specific spiral-angle structure is designed in order to suit the requirement of low-speed and heavy-load.The influence of different sprial-angles and groove structures on the elastic hydrodynamic lubrication characteristics of water-lubricated rubber bearings are analysed.In the meanwhile,the lubrication characteristic is discussed under reverse flow condition.The results show that the influence of different groove structures on the lubrication characteristics are different,which is seleted by the different area according to the actual working condition.The groove angle of the spiral-groove is related to the flow field.When the direction of the flow field coincides with the direction of the sprial-angle,the pressure distribution fluctuates less and the velocity of the flow field is uniform on the whole,and does not produce a large influence in the local area.what's more,the integrity of water film is better.For the reverse flow problem,its lubrication characteristic can be improved through the reasonable arrangement of fillet and groove.