Hitachi, Ltd.

Western Digital Technologies, Inc.

Masaki Otsuka

Iwao Matsuyama

Masayuki Katsumoto

Nobuyuki Ishii

Kazuhisa Murakami

Mitsuhiko Oguchi

Shuntaro Takeuchi

Toshiya Shiramatsu

Satomi Yamaguchi

Tsuneyuki Hasegawa

An idle sweep routine for a hard disk drive involves a series of servo-controlled one-Nth (1/N) equivalent sub-band random seeks in one radial direction, followed by another series of servo-controlled one-Nth equivalent sub-band random seeks in the other radial direction, where a complete band refers to the complete set of user-data tracks and a one-Nth sub-band refers to a contiguous 1/N portion of the complete band. For example, a first series of ⅕ sub-band random seeks may be in the disk outer diameter (OD) to inner diameter (ID) direction, followed by a second set of ⅕ sub-band random seeks in the ID to OD direction. Based on disk scratch and Si smear robustness, ⅕ sub-band random seeks are found effective in moving the sider over a significant number of tracks during each seek to likely inhibit disk lubrication degradation and avoid thermal asperities during such an idle sweep routine.

Hard disk drive idle sweep for thermal asperity avoidance

Gas contaminants generated from the grease of bearings operating in a magnetic disk device adhere to the magnetic head and causing stiction and magnetic head crash. Such bearings are typically spindle bearings and pivot bearings. In operation, heat is generated that causes the bearing grease to generate the gases. By heat treating the grease, slow evaporating substances of hydrocarbon compounds with carbons of C9 to C13 in the grease are reduced to not more than 0.001 wt. % of the grease. The grease can then be used to lubricate the bearings. The heat treatment is performed at a temperature of 60.degree. to 100.degree. C. at a pressure of 10.sup.-3 to 10.sup.-8 torr. The assembled, lubricated bearings can be heat treated separately from the magnetic disk device or the heat treatment can take place after the bearings have been assembled in the magnetic disk device.

Bearing and manufacturing method of bearing, and magnetic disk device

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Odawara, Japan

Masaki Otsuka