Fluid-dynamic-pressure bearing furnished with a shaft, a top
plate fixed to an upper portion of the shaft, a thrust plate fixed to a lower portion
of the shaft, a sleeve, and a cuplike bearing housing that along its inner periphery
retains the sleeve. A lubricating-fluid-filled continuous micro-gap is formed in
between the shaft and the sleeve and the top plate and the sleeve. Radial bearing
sections are formed in between the shaft cylindrical outer surface and the sleeve
cylindrical inner surface. An upper thrust bearing section is formed in between
the undersurface of the top plate and the top-edge face of the bearing housing.
A lower thrust bearing section formed in between the bottom margin of the sleeve
and the top margin of the thrust plate. The bearing sections are each provided
with dynamic-pressure-generating grooves for inducing dynamic pressure in the lubricating
fluid when the shaft or sleeve spins.