Development of Orifice-type Aerostatic Thrust Bearing for Precision Machine

Air bearings are used in precision machines and measurement equipments for recently years. Unlike conventional ball or roll bearings, there is no physical contact between the sliding surfaces and the moving surface. Therefore, the structure with air bearings can glide smoothly on the other surface to avoid generating the small particles from the friction contact and also minimize the control effort to achieve high accuracy and precision. To exploit this phenomenon, simple theoretical analysis for orificetype air bearing was carried out avoiding complexities in the formulation and the governing parameters were kept at a minimum. This helped in easy understanding of the dynamics and performance behavior of the air bearings. A simple design methodology was also developed to assist in the design or the selection process of the bearing and a three-dimensional model was built for Computational Fluid Dynamics (CFD) analysis to verify the theoretical result. Finally, a test set-up was designed to measure and study the static and dynamic performance of different kind of air bearings for future air bearing development. Moreover, the experimental data were also taken and compared with the analytical results.