Numerical Investigation of Static and Dynamic Characteristics of Water Hydrostatic Porous Thrust Bearings
Yuki Nishitani, Shigeka Yoshimoto, and Kei Somaya
Department of Mechanical Engineering, Tokyo University of Science, 1-14-6 Kudan-kita, Chiyoda-ku, Tokyo 102-0073, Japan
A moving table supported by aerostatic bearings can achieve excellent accuracy of motion because of its noncontact support and, hence, it is used in various precision machine tools and measuring equipment. However, because of low viscosity of air, the damping coefficient of aerostatic bearings is not very high, causing vibration with nanometer-order amplitudes. The accuracy of machine tools and measuring equipment could deteriorate because of this vibration. It is expected that water hydrostatic bearings would have a higher damping coefficient than aerostatic bearings due to the higher viscosity of water. In addition, water, like air, does not pollute the environment. In this paper, the static and dynamic characteristics of water hydrostatic thrust bearings using porous material were numerically investigated and comparedwith conventional pocket hydrostatic bearings with a capillary restrictor. Hydrostatic porous bearings can be easily constructed because the porous material becomes a viscous restrictor itself. It was consequently found that water hydrostatic porous thrust bearings have higher maximum load capacity and slightly lower stiffness than water bearings with a capillary restrictor.
-  K. Sawada, T. Kawai, and K. Ebihara, “Laminarization of air bearing in the nano machine,” FANUC Tech. Rev., Vol.16, No.1, pp. 1-6, 2003.
-  A. H. Slocum, P. A. Scagnetti, N. R. Kane, and C. Brunner, “Design of self- compensated water-hydrostatic bearings,” Precision Eng., Vol.17, pp. 173-185, 1995.
-  N. Kusui, S. Hayama, A. Ohtomo, and M. Yoshikawa, “Study on Fluid-Static Bearing Using Water as Pressure Fluid – Defining of Design Rule of Fluid Element –,” Trans of JSPE, Vol.64, No.6, pp. 851-855, 1998. (in Japanese)
-  N. Kusui, S. Hayama, and M. Yoshikawa, “A Study on Linear Motion Stage Using Water-Hydrostatic Bearing,” Trans. JSPE, Vol.65, No.8, pp. 1153-1157, 1999. (in Japanese)
-  S. Okuyama, A. Yui, M. Kumagai, and T. Kitajima, “Development of a Linear-Motor-Driven Table with Hydrostatic Water Bearings (Basic Design of a Constant-Flow Hydrostatic Bearing),” Trans. JSME, Vol.75, No.750, pp. 454-459, 2009. (in Japanese)
-  A. Yui, M. Kumagai, T. Kitajima, S. Okuyama, E. Fujita, and A. H. Slocum, “Development of a Linear-Motor-Driven Table with Hydrostatic Water Bearings (design and Development of the Table System and Its Static Characteristics),” Trans. JSME, Vol.75, No.752, pp. 1128-1134, 2009. (in Japanese)
-  I. S. Durazo-Cardenas, J. Corbett, and D. J. Stephenson, “The performance of a porous ceramic hydrostatic journal bearing,” Proc. IMECHE, Part J, J. Eng. Trib., Vol.224, pp. 81-89, 2010.
-  S. Yoshimoto and K. Kohno, “Static and Dynamic Characteristics of Aerostatic Circular Porous Thrust Bearings (Effect of the Shape of the Air Supply Area),” Trans. ASME, J. Trib., Vol.123, No.2, pp. 501-508, 2001.
This article is published under a Creative Commons Attribution-NoDerivatives 4.0 Internationa License.