Title: A study of magnetic fluid rotary seals for wafer handling robot

Authors: Ming Cong, Huili Shi

Addresses: Key Laboratory for Precision and Non-traditional Machining Technology of Ministry of Education, Dalian University of Technology, Dalian, Liaoning Province 116024, PR China. ' Key Laboratory for Precision and Non-traditional Machining Technology of Ministry of Education, Dalian University of Technology, Dalian, Liaoning Province 116024, PR China

Abstract: Magnetic fluid rotary seals have been shown to be effective in machinery operating in a vacuum chamber. Such seals have the advantages of simple design, zero leakage at almost any rotation speed and low friction. This paper presents the principle of magnetic fluid rotary seals technology. The seal differential pressure formulas of magnetic fluid rotary seals are deduced and obtained. The magnetic field distribution of the sealing gap flux densities is calculated by finite elements method through solving the magnetic vector potential with appropriate boundary conditions. Based on the magnetic field calculations, the influence of sealing gap and tooth parameters on seal pressure differential is analysed. A coaxial twin-shaft magnetic fluid seal apparatus used for wafer handling robot is presented. It is shown that using the most advanced magnetic fluid technology and seal design technology, magnetic fluid rotary seals can provide satisfactory performance in this challenging new application.

Keywords: magnetic fluids; rotary seals; magnetic field; wafer handling robots; vacuum chambers; differential pressure; finite element method; FEM; sealing gap; tooth parameters; seal pressure; SCARA robots.

DOI: 10.1504/IJISTA.2010.030197

International Journal of Intelligent Systems Technologies and Applications, 2010 Vol.8 No.1/2/3/4, pp.158 - 170

Available online: 11 Dec 2009 *

Full-text access for editors Access for subscribers Purchase this article Comment on this article