Fluid dynamic pressure bearing, a spindle motor with the fluid dynamic pressure bearing, and recording dis chains - running gear with the spindle motor

摘要

A fluid dynamic pressure bearing includes dynamic pressure grooves formed between a shaft member and a bearing member. The shaft member includes a flange portion 1 - 2 , and a capillary seal portion 8 is formed between an outer circumferential surface of the flange portion and an inner circumferential surface of the bearing member. An annular labyrinth member 4 is engaged with an upper portion of the bearing, and a labyrinth seal portion is defined by (i) an annular protrusion 1 - 4 formed on an upper end surface of the flange portion and facing the labyrinth member via a micro gap and/or (ii) an annular protrusion 4 - 2 formed on a lower end surface of the labyrinth member and facing the flange portion via a micro gap.