A rotational member and a stationary member included in a spindle motor
provided with air bearings are electrically connected while the bearing
is rotating, and abrasion of the rotational member and the stationary
member at stages of starting and stopping and damaging the rotational
member and the stationary member by external shocks that may be exerted
thereon during transportation and handling are avoided. In one
embodiment, a sleeve is formed integrally with a motor base. The sleeve
has an inside surface serving as a radial-bearing surface that forms a
radial bearing together with the outside surface of a rotational shaft,
and a thrust-bearing surface that forms thrust bearing together with a
thrust plate attached to the rotational shaft. The radial-bearing surface
of the sleeve is provided with a recess (groove) for holding lubricating
oil while the rotational shaft is rotating. A gap not forming a bearing
is formed between the circumference of the thrust plate and the inside
surface of the sleeve to hold the lubricating oil while the rotational
shaft is rotating.