Patent ID: 7210850

Claim:
A hydrodynamic bearing device comprising: a sleeve having a bearing bore substantially at a center portion between the upper and lower surfaces; a shaft disposed in the bearing bore in a rotatable manner with the shaft having a step portion with a reduced diameter in a vicinity of the upper surface of the sleeve; a thrust plate supporting a first end of the shaft in a thrust direction; and a cap portion having an opening portion with the shaft disposed therein and covering the upper surface of the sleeve, the sleeve and the shaft being arranged to form a hydrodynamic bearing between the bearing bore of the sleeve and the shaft, the thrust plate and the shaft being arranged to form a hydrodynamic bearing between the thrust plate and the first end of the shaft, the sleeve and the cap portion being arranged to form a first space between the upper surface of the sleeve and the cap portion, the first space having a width in an axial direction of the shaft that increases from a vicinity of the bearing bore toward an outer rim of the sleeve, and the cap portion and the step portion of the shaft being arranged to form a second space formed between the cap portion and the step portion, the second space having a width in the axial direction that increases from a vicinity of the bearing bore toward a center of the shaft.