| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a closed type thrust dynamic pressure bearing which can sufficiently generate dynamic pressure for axial support at the time of starting without damaging end faces and the like. SOLUTION: A flange 1 of a rotational body 3 is housed in a housing 2 in a sealed state. V-shaped dynamic pressure generating grooves 8 are formed on upper and lower end surfaces 5, 6 of the flange 1, while plural holes 11 are formed on the flange 1 so as to penetrate axially to the inner side in a diameter direction compared to the dynamic pressure generating grooves 8. Total sum of the sectional areas of the axially penetrating holes 11 is at least 1/30 of the area of a circular area 7. An oil reservoir 13 is formed on a reception surface 12 of the housing 2, opposed to the lower end surface 6 of the flange 1.</p> |
