FLUID DYNAMIC PRESSURE BEARING, MOTOR, AND RECORDING MEDIUM DRIVE DEVICE

摘要

A fluid dynamic pressure bearing (1) capable of suppressing the production of air bubbles by stably supplying a working fluid to a dynamic pressure generating groove and effectively preventing vibration from occurring in rotating and the working fluid from leaking by efficiently escaping the produced air bubbles. An annular dynamic pressure generating surface (17) formed by forming the dynamic pressure generating groove for drawing the working fluid (14) from the radial inner and outer sides of a thrust bearing plate (13) to a radial midway position when a shaft (10) and a housing (11) are rotated relative to each other around their axes in the end faces (13a) and (13b) of the thrust bearing plate (13) in the thickness direction or the inner surface of the housing (11) and an inside groove part (16) disposed on the inner peripheral side of the dynamic pressure generating surface and recessed in the thickness direction more than the dynamic pressure generating surface (17) are formed in the end faces (13a) and (13b). Through holes (19) passed through the thrust bearing plate (13) in the thickness direction are formed in the dynamic pressure generating surface (17), and communication recessed parts (20) connecting the opening parts of the through holes (19) to the inside groove part (16) are formed in the dynamic pressure generating surface (17).