Abstract
This paper describes the robust optimum design considering dimensional tolerances for hydrodynamic air bearings of small size hard disk drives (HDDs). Hydrodynamic bearings for HDD spindle motors are generally manufactured by mass production processes which will eventually require reduction of production costs. Consequently, the hydrodynamic bearings are demanded to be easily manufactured and expected to have an insensitive design with low variability of bearing characteristics due to manufacturing errors. In this paper, the bearing characteristics are calculated considering dimensional tolerance using optimum design combined with statistical method in which the dimensional tolerance is assumed to distribute according to the Gaussian distribution. The bearing characteristics are estimated by expectation and standard deviation, and then Pareto solutions are obtained using the multi-objective genetic algorithm.
