Contact And Lubrication Performance Of Water Lubricated Rubber Alloy Bearings

Owing to the low viscosity of water and special material properties of rubber bushing, the water lubricated rubber alloy bearings have performances different from those of traditional oil lubricated metal bearings in the lubrication mechanism. For the water lubricated rubber alloy bearings with multi-groove structure, the lower film pressure can occur. Meanwhile, owing to the low elasticity of rubber materials, serious deformation can appear on the bushing of the bearings, even on the relatively lower film pressure, thus changing the water film thickness and its shape, and further affecting the film pressure distribution. Therefore, in the case of the lubrication mechanism of water lubricated rubber alloy bearings, what should be considered not only including their structure like multi-surface and multi-groove ones, but also including their material properties of rubber bushing.A finite element method (FEM) was employed in order to gain an insight into the lubrication characteristics of a water lubricated rubber alloy bearing under the conditions of heavy load and dry friction, where dynamic contact analysis of the bearing was carried out with different loads and different friction coefficients. The study shows that the maximum contact stress, maximum contact displacement and the maximum strain usually exist at both ends in bearing length direction or the downstream along the rotation direction of the bearing.The lubrication performance of the water lubricated rubber alloy bearings were analyzed at a full circumferential scale using fluid-structure interaction technique. A governing equation suitable for this kind of bearings is first established based on Navier-Stokes equation and associated elastic theories, combining the particularity of the water lubricated rubber alloy bearings with a fluid-structure interaction technique. The film pressure and the deformation distributions of the rubber bushing are separately investigated on the condition of different eccentricities and different speeds using numerical simulation method, further the corresponding water film thickness distribution, load-carrying capacity and friction coefficient achieved. Afterward, influences of some factors, including the radius of corner, the thickness of rubber and material properties of bushing, on lubrication performances of the bearings are studied.The numerical results reveal that the load-carrying capacity of a water lubricated rubber alloy bearing is lower in the case of eccentricity ratio less than and equal to unit (the maximum pressure of 0.08Mpa can be found in the present study). It is also found that a decreasing radius of corner for the bearing increases the convergent wedge length, which is helpful to the improvement of load-carrying capacity, while in the case of large eccentricity ratio, the film pressure for the bearing will decrease with increasing rubber bushing thickness. In the same rigid clearance, the lower elasticity modulus of bushing material, the thicker water film, but the smaller load-carrying capacity.This research is funded by the State Natural Sciences Foundation General Projects:"Innovative design theory and method of water lubricated bearing system with large size and high specific pressure"(Number:50775230). The paper will provide a reference for the study of lubrication mechanism and research methods.