Property Analysis of the Rough Slider Bearings in Micromotors for MEMS Applications

Based on the kinetic theory of gases, a new slip model is applied for the gas-lubricated Rayleigh slider bearings beneath three bushings of a micromotor in microelectromechanical systems (MEMS). A modified Reynolds equation is established by taking into account of the coupling effects of gas rarefaction and roughness and then analytical solutions for pressure distribution, load-carrying capacity and its streamwise location, and velocity profile are obtained for various slider-bearing configurations. The new slip model is validated by comparisons with the results presented in other researcherspsila works. It is indicated that the present new slip model is of better accuracy in predicting the bearing properties than the first-order, second-order slip models, and modified molecular gas lubrication model and is a good approximation to variable hard sphere and variable soft sphere models. The solutions provided by the present new slip model match the solution obtained using the linearized Boltzmann equation very well. The results also show that the coupled effects of gas rarefaction and roughness are of great significance in the design of the bushings for slider bearings in micromotors.