Patent ID: 7677805

Claim:
A fluid dynamic bearing comprising: a journal bearing part supporting a rotary shaft of a hard disk in a radial direction of the rotary shaft; a thrust part formed at one end of the rotary shaft; a thrust bearing part facing the thrust part and supporting the rotary shaft in a longitudinal direction of the rotary shaft; and a plurality of grooves formed on a surface of at least one of the thrust bearing part and the thrust part, wherein the plurality of grooves comprise: a first groove group disposed on a first portion of the surface and including a plurality of grooves having the same shape and arrangement; and a second groove group disposed on a second portion of the surface corresponding to a portion of the hard disk where a load is applied by a head, and including at least one groove asymmetric with respect to the grooves of the first groove group, wherein the second groove group includes a plurality of grooves having different widths, and among the plurality of grooves of the second groove group, a width of a groove located at a center of the second groove group is relatively less than a width of a groove adjacent to the first groove group.