FLUID DYNAMIC PRESSURE BEARING APPARATUS

摘要

A fluid dynamic pressure bearing apparatus includes a radial dynamic pressure bearing formed in a gap portion between a bearing member and a shaft member. The apparatus also includes a thrust dynamic pressure bearing having a first thrust bearing portion formed between a top surface of the thrust plate and a first facing member opposing thereto in the axial direction and a second thrust bearing portion formed between a bottom surface of the thrust plate and a second facing member opposing thereto in an axial direction. Dynamic pressure generating grooves are formed on the radial dynamic pressure bearing and the thrust dynamic pressure bearing. The shaft member and the bearing member are rotated together as a rotation member, such that the rotation member is supported in a position such that a gap space L 1 of the first thrust bearing portion is larger than a gap space L 2 of the second thrust bearing portion and the depth of the dynamic pressure generating grooves where the gap space is smaller is formed shallower than that where the gap space is larger.