Load Mechanism Research Of Hydrostatic Oil Pad Bearings Under Oil-gas Phase Flow Lubrication

As sliding bearings have advantages of high rotation accuracy, good damping and vibration performance, no wear and long service life, they are still equipped on the high speed and high precision grinding machine, lathe, and high speed and high precision CNC. However, the traditional air bearings at high speed but low bearing capacity, and liquid bearings at low speed but high bearing performance, not only restricts the development of spindle bearing technology in high speed and heavy load greatly, but also restricts the development of the ultra-high speed, super precision and big load equipment technology in our country.As a new kind of technology lubrication, oil-gas lubrication technology has advantages of excellent cooling lubrication performance, low fuel consumption, good lubrication, high efficiency, economy and environmental, compared with traditional single phase flow lubrication. oil-gas two phase flow lubrication, has been applied in the field of multiple lubrication. At present, the oil-gas lubrication technology applied to the hydrostatic bearing successfully, which has not been seen in publicly reports. It is appears large difference on lubrication performances of dynamic bearings under oil-gas lubrication from the research at home and abroad. As the complexity of viscosity and rheological features of oil-gas two flow, the lubrication theory of oil-gas two phase flow are not wealth. The research results under different conditions always appear difference. But all the research shows that oil-gas lubrication applied to sliding bearings are effectiveIn this thesis, oil-gas lubrication is applied to hydrostatic bearings, oil and gas medium delivered correctly, rheological effect occurred and a stable and uniform oil-gas film formed in the bearing gap, it achieves good bearing capacity and compressed air take off the friction heat efficiently. The purpose of research is to develop a new type of sliding bearing lubrication technology, to improve the comprehensive performance of sliding bearings. Due to the relevant theoretical research is not enough mature, as the result there is no effective oil-gas lubrication theory on hydrostatic bearing. This article attempts to carry out the related fundamental research from the oil-gas film bearing mechanism of hydrostatic bearing, through simulation and experimental research.Research carried out from the following several aspects:1. Design hydrostatic oil pad bearings, to simulation the hydrostatic bearing lubrication condition. Mirror and improve the rotary viscosity test method, viscosity model of oil-gas two-phase flow is established in this thesis. The oil-gas lubrication Reynolds correction equation of sliding bearing is derivative through theoretical research. Hydrostatic bearings belong to multi-point lubrication, the lubrication condition needs lubrication medium keeps stability and homogeneity rigorous, therefore a combine simulation method is proposed in this thesis, based on VOF multiphase flow model, research on distribution of oil-gas film in bearing gap, explore proportion of oil-gas flow to suitable for hydrostatic bearing lubrication structure content. On this basis, simulation research on static load characteristics of oil-gas film.2. Oil lubrication system consists of oil-gas flow generator device, transmission device and lubrication structure. It is necessary to research on the category and characteristics of oil-gas flow in the tube, to explore a flow pattern which is suitable for the lubrication structure of the hydrostatic bearings. In this thesis, combine simulation method is used to simulation research on the formation of oil-gas annular flow in the tube, and the influence on formation of oil-gas annular flow by liquid phase speed and gas phase speed. Combining with the theory of oil-gas flow, reveal the transformation mechanism of oil-gas annular flow in the tube, it is better to hydrostatic bearing lubrication condition.3. According to the characteristics of hydrostatic bearings and study the key parts of oil-gas lubrication system, determine the design parameters and lubrication condition of hydrostatic oil pad bearings, build a hydrostatic oil pad bearing float test bed, and equipped with an oil-gas lubricating system suitably.4. Carry out the oil-gas film static load experiment in the hydrostatic oil pad bearings float test bed. Set various load conditions, and choice the axial float displacement as performance indicators, choice rate of oil, lubricating oil viscosity, orifice size, and the bearing clearance as experimental variables to carry out the experimental study, and get the hydrostatic oil pad bearing displacement and the load curves and stiffness curves. And compared with the single phase fluid (gas or liquid) lubrication condition.