Research On Thermo-mechanical Coupling Deformation And Oil Film Model Of Hydrostatic Bearing

With the rapid development of modern machinery manufacturing industry, hydrostatic bearing has been widely used in high precision numerical-controlled machine tool. It has a series of advantages that have been recognized, such as good load carrying ability, small friction coefficient, long service lifetime, high kinematic accuracy and so on, which is widely used in important national industrial fields such as aerospace, ship, wind power equipment manufacturing industry, heavy machinery. Its lubricating property and load carrying ability will directly affect the working accuracy and efficiency of complete machine. Under ordinary working conditions, thermomechanical coupling deformation will make the shape of interstitial oil film complex, which makes oil-flow status, basic underlying assumption and boundary conditions generate great changes. It is hard to accurately predict the lubricating property of hydrostatic bearing by theoretical formula, and thermomechanical coupling deformation cannot be neglected when analyzing the property of hydrostatic bearing.According to the upper content, this paper takes the hydrostatic bearing with multiple oil pads whose oil chambers are fan-shaped as a research object. And this paper unites fluid mechanics, thermomechanical coupling technique and numerical simulation to make thermomechanical coupling simulation research by ANSYS and thermomechanical coupling technique. The main work that has been done is as follow.(1) According to the actual size of the hydrostatic bearing structure, establish the three-dimensional geometric model and interstitial oil film model. Derive the equations of oil chamber flow, load carrying ability, oil chamber pressure, total power consumption of oil film and temperature rise equation. Use the FLUENT software to make simulation analysis on temperature field and pressure field of interstitial oil film under different loading conditions. The results of temperature field and pressure field of interstitial oil film provide preconditions for the next thermo mechanical coupling analysis.(2) Based on tribology, heat transfer and elastic plasticity deformation theory, this paper uses the software ANSYS14.5 Workbench to make thermomechanical coupling analysis on hydrostatic bearing to get its temperature fields and thermomechanical coupling deformation fields under different loading conditions, such as 15 t, 30 t, 45 t, 60 t, 75 t, 90 t, 105 t, 120 t, 135 t and150t, and detailedly discusses the computed results under different loading conditions.(3) On the basis of the total deformation of work bench and base frame, get the parameter model of interstitial oil film and the curve of oil film thickness-load. And it is found that the deformed oil film takes on wedge-shape as a whole, and that the outside of fan-shaped oil film in radial direction is higher than its inside so that the inside easily generates dry friction to make lubrication disabled as the loading increases, which provides a theoretical basis for designing hydrostatic bearing.