Analysis of Hydrostatic Bearings Based on a Unstructured Meshing Scheme and Turbulence Model

Abstract

Guideway hydrostatic bearings with the function of supporting and moving loads are a key component of ultra-precision heavy-duty machine tools. Because the dimension difference between the oil gap and the overall structure is great, it is difficult to generate the three-dimensional mesh, which has limited the improvement of bearing performance through structural innovation. To solve these problems, we propose an approach using the global fluid domain for performance analysis. The grid skewness of the film region and other regions are less than 0.4 and 0.8, respectively, which can satisfy the demands of static and dynamic high-accuracy simulation. Then, we used supporting load capacity, stiffness and damping to analyze the performance of hydrostatic bearings. The average error between the simulation result and the actual value was 10.76%, which is better than the result calculated by the traditional empirical formulae. The stiffness and damping of the bearings are easy to obtain by application of dynamic mesh technology. Furthermore, many obvious vortices were shown by visualization analysis in the bearing internal flow pattern in the bearing moving state of 400 mm/s. Finally, a specially designed double-slit septum successfully suppressed the formation of visible vortices. This structural improvement, combining the advantages of deep and shallow recesses, is expected to make hydrostatic bearings at high-speed conditions more stable for ultra-precision machine tools.