Reseach On The Performance Of Externally Pressurized Gas Bearing With Vacuum Pre-Load

Aerostatic bearings have the merit of high precision and speed, high motion resolution, small reptiles, less pollution, good thermal stability etc, so it is widely used in precision measuring instruments, ultra-precision machining and micro-machining and other engineering applications, which also make aerostatic guide develop rapidly. However, the problems such as complex structure and large size still exist in plane closed aerostatic guide, cylinder aerostatic guide and gravity balanced aerostatic guide. In this paper, the vacuum pre-load technology is adopted to add vacuum chamber through externally pressurized gas bearing, which not only can facilitate the structure of aerostatic guide, but also can improve the load capacity of guide.Based on the analysis and comparison of aerostatic bearing at home and abroad, taking rectangular gas bearing and round gas bearing for example, this paper focuses on the relationship of gas bearing with vacuum chamber and the load capacity of aerostatic bearing, which includes the following parts:First, based on the Reynolds equation of steady state non dimensional form, reduce the partial differential equations by using the weighted residual method; then, applying the interpolation function of film pressure, turn the problem of gas lubrication into nonlinear terms of pressure equations through the method of finite element.On the basis of the steady state mathematical model of vacuum pre-load Aerostatic thrust bearings, this paper will solve the pressure equation by the software of MATLAB program which can calculate the static characteristic of aerostatic bearing in different area of the vacuum chamber.The simulation analysis method is adopted to analyze the rectangular vacuum pre-load aerostatic bearing. This paper compares the effects of vacuum pre-load on the basis of the influence of vacuum chamber's area on bearing characteristic and the variation rules of aerostatic bearing's static characteristic in different parameters.The computational analysis method is adopted to analyze the round vacuum pre-load aerostatic bearing. This paper mainly investigates the effects of vacuum chamber's area on bearing characteristic, and analyzes the variation rules of aerostatic bearing's static characteristic and the results of vacuum pre-load.At last, perform the experiment with processed sample, prove the validity of theoretical models and vacuum pre-load technology by analyzing and comparing experimental measuring values and theoretical calculating values.The research of this article is benefit for the further improvement of the theory of aerostatic bearing, can provide theoretical support for engineering application of vacuum pre-load aerostatic guide, besides, it also has the profound significance to the development of aerostatic bearing.