Patent ID: 8169738
Filing Date: 2012-05-01
Classification: F16C,G11B,H02K

Abstract:
1. A fluid dynamic bearing mechanism comprising: a stationary bearing portion; and a rotating bearing portion supported to be rotatable with respect to the stationary bearing portion; wherein the rotating bearing portion includes: the stationary bearing portion includes a sleeve portion, the sleeve portion including an upper surface arranged opposite a lower surface of the outer rotating portion, and a bearing hole arranged opposite the shaft portion; a lubricating oil is arranged between the stationary and rotating bearing portions; a liquid surface of the lubricating oil is arranged between the stationary bearing portion and the outer rotating portion; the lower surface of the outer rotating portion or the upper surface of the sleeve portion includes a first dynamic pressure groove array arranged therein to induce a dynamic pressure in a substantially radially inward direction in a portion of the lubricating oil which is present between the lower surface of the outer rotating portion and the upper surface of the sleeve portion; a surface of the outer rotating portion or a surface of the stationary bearing portion includes a second dynamic pressure groove array arranged therein and arranged to induce a dynamic pressure directed to an interior of the fluid dynamic bearing mechanism in a portion of the lubricating oil which is present between the first dynamic pressure groove array and the liquid surface; an end of the second dynamic pressure groove array which is arranged closer to the liquid surface is arranged radially inward of an end of the second dynamic pressure groove array which is arranged closer to the first dynamic pressure groove array; the sleeve portion includes a communicating channel arranged to connect an upper end opening arranged in the upper surface of the sleeve portion and a lower end opening arranged in another portion of the sleeve portion, the communicating channel being provided separately from the bearing hole; and the upper end opening is arranged radially outward of a radially inner end of the first dynamic pressure groove array.