Characteristic Analysis of Rotor System due to the Positioning Angles of HDD Supported by Fluid Dynamic Bearings

This research investigates experimentally and numerically the tilting angle, eccentricity ratio, flying height of axial direction, friction torque, and critical mass of the HDD disk-spindle system due to HDD positioning angle. The tilting angle and the eccentricity ratio are the maximum when the HDD positioning angle is 90?? respect to horizontal position because the external force in radial direction and the torque applied to the rotating part are the maximum when the HDD positioning angle is 90??. The flying height increases with the increase of the HDD positioning angle because the direction of gravity applied to the rotating part changes. The friction torque increases with the increase of the HDD positioning angle until it becomes 60??, and decreases with the increase of the HDD positioning angle after it becomes 60??. The stability is the maximum when the HDD positioning angle is 90??