FLUID DYNAMIC BEARING MECHANISM, SPINDLE MOTOR AND DISK DRIVE APPARATUS

摘要

PROBLEM TO BE SOLVED: To provide a fluid dynamic bearing mechanism for restraining generation of bubbles in lubricating oil.

SOLUTION: This fluid dynamic bearing mechanism 105 includes a stationary bearing portion 103 and a rotating bearing portion 104. The stationary bearing portion includes a sleeve portion 137, and the rotating bearing portion 104 includes a shaft portion 141 and an outer rotating portion 142. The lubricating oil 151 is interposed between the stationary bearing portion 103 and the rotating bearing portion 104. A first dynamic pressure groove array 165 is arranged on an upper surface of the sleeve portion 137, and a second dynamic pressure groove array 166 is arranged on a surface of the stationary bearing portion 103. An end portion on the liquid level 151a side of the second dynamic pressure groove array 166 is positioned inside in the radial direction more than an end portion on the first dynamic pressure groove array side 165 of the second dynamic pressure groove array 166. An upper opening 162a of a communicating passage 162 arranged in the sleeve portion 137 is positioned outside in the radial direction more than an inside end portion in the radial direction of the first dynamic pressure groove array 165. This structure can restrain generation of the bubbles in the lubricating oil.

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