Nidec Corporation

Hirofumi Kojima

Tetsuya Maruyama

Yoichi Sekii

Junya Mizukami

Atsushi Yawata

Masayoshi Saichi

Michihiro Ito

Makoto Kutsukake

A fluid dynamic pressure bearing includes a shaft arranged along a central axis, an annular member fixed to the shaft, a sleeve, a lubricant, and a lubricating film. A stepped surface is provided on the outer circumferential surface of the shaft. The annular member preferably includes a lower surface extending radially with respect to the central axis and arranged to make contact with the stepped surface in the inner edge portion of the lower surface. The sleeve preferably includes an upper surface axially opposed to the lower surface of the annular member. The lubricant is provided between the shaft and the sleeve and between the annular member and the sleeve. The lubricating film is provided on the lower surface of the annular member at least over a region lying radially outwardly of the inner edge portion of the lower surface.

Dynamic fluid pressure bearing, spindle motor, disk drive apparatus and method for manufacturing the dynamic fluid pressure bearing

A fluid dynamic bearing mechanism includes a stationary bearing portion including a sleeve portion, and a rotating bearing portion including an outer rotating portion. A lubricating oil is arranged between the stationary and rotating bearing portions. A first dynamic pressure groove array is arranged in an upper surface of the sleeve portion or a lower surface of the outer rotating portion. A second dynamic pressure groove array is arranged in a surface of the outer rotating portion or a surface of the stationary bearing portion in a region between the first array and a liquid surface. An end of the second array closer to the liquid surface is arranged radially inward of an opposite end of the second array. An upper end opening of a communicating channel defined in the sleeve portion is arranged radially outward of a radially inner end of the first array.

Fluid dynamic bearing mechanism including communicating channel, spindle motor, and disk drive apparatus

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Kyoto, Japan

Hirofumi Kojima