A gas dynamic bearing motor is provided that is capable of setting a bearing
radius
to a large value to obtain a sufficient radial stiffness, and preventing lock of
the bearing and scattering of wear powder outside the bearing. An annular groove
11 is provided on a lower end surface 87 of a hub 3 to thereby
enable a deformation of an inner circumferential surface 82 of the hub 3
when recording disks 9 are loaded on the hub 3 to be suppressed
to a small value, thereby enabling partial contact in the radial bearing to be
suppressed and lock of the bearing to be prevented. Further, a protrusion 12
is provided on a base 7 in a circumferential direction and fitted in
the annular groove 11 to construct a labyrinth seal, thereby enabling scattering
of wear powder generated on bearing surfaces outside the bearing to be prevented.
