Fluid bearing spindles for data storage devices

Abstract

Four different types of fluid bearing, hydrodynamic, aerodynamic, hybrid hydro-aerodynamic bearing, and bi-directional rotating bearing are introduced and analyzed for applications in data storage devices. Hydrodynamic bearings have higher load and shock resistance, while aerodynamic bearings are more suitable for higher speed applications. A hybrid bearing can save power consumption up to 30% compared to hydrodynamic bearing. A bi-directional rotating bearing has a wider application range but its power consumption is 50% higher than a one-directional rotating bearing. Study of the effects of design parameters on bearing performance using Taguchia??s method shows that the most important and sensitive parameter is bearing clearance. The prototypes of hydrodynamic and hybrid bearings were fabricated and tested. The test results show that the non-repeatable run-out of spindle motors using such fluid bearings can be reduced to less than 0.05 micrometer and the acoustic noise is about 6 dB(A) lower than that of ball bearing spindle motors.