A miniature spindle motor with fluid dynamic bearings for portable storage device applications

This paper presents the design and fabrication of a miniature axial-gap spindle motor for small-form-factor optical storage applications. The motor features a fluid dynamic bearing (FDB) and is characterized by a high mechanical rigidity, excellent dynamic characteristics, and a zero cogging torque. The performance of this FDB motor is evaluated experimentally using a laboratory-built prototype. The results show that the motor has an excellent dynamic response, a small axial repeatable runout, a small tilt angle, a high rotational speed, and a low operating current. Furthermore, with overall dimensions of just 15.5 × 3.3 mm, the FDB motor is around 80% smaller than that presented by the current group in a previous study (Liu et al., J Magn Magn Mater 304:362–364, 2006). Consequently, the proposed motor represents an ideal solution for both existing and emerging miniaturized portable storage device applications.