Closed type thrust dynamic pressure bearing with through hole

Abstract

A closed type thrust dynamic pressure bearing is capable of generating enough dynamic pressure for axially bearing a rotating member at the time of start-up without damage to an end face of a flange of the rotating member. The flange of the rotating member is housed in a housing in a closed state. V-shaped dynamic pressure generating grooves are provided at upper and lower end faces of the flange, while a plurality of holes axially passing through the flange are provided radially inside an annular region where the dynamic pressure generating grooves are provided. The total sum of cross-sectional areas of the holes is at least 1/30 of the area of the annular region. Oil sumps are provided at a receiving surface of the housing opposite to the lower end face of the flange.

Dependencies are inferred from the claim text.