Matsushita Electric Industrial Co., Ltd.

Akihide Matsuo

Hideshi Fukutani

Norishige Moritan

Takao Yoshitsugu

Katsunori Sakuragi

Hiroyoshi Teshima

Shoichi Yoshikawa

Akihiko Wakitani

It is an object of the present invention to provide a motor capable of reducing a loss as much as possible, and securing minimum vibration proof performance and reliability by definitely defining the upper and lower limits of a minimum shaft diameter in conformity with a disk load, the service number of revolutions or the like. In a shaft-fixed type motor of the fluid bearing specifications, the diameter d (mm) of a fixed shaft is set so as to satisfy the relation of &agr;,&middot;M1 >d,>M1, where M1&equals;J1&middot;(N/1000),&middot;k,&middot;D, J1 being a coefficient to be experimentally determined, N(rpm) the service number of revolutions, k the number of a disk-shaped recording media, D (inch) the diameter of the disk-shaped recording medium, and &agr; a ratio of the maximum diameter to the minimum diameter of the fixed shaft.

Motor and hard disk drive having a reduced vibration motor

In a spindle motor for a driving a memory disk, a is closed space formed by a sleeve metal, an end portion of a shaft and a thrust plate. The closed space is connected to outside open space by a connection path, thereby effectively discharging undesirable air in an assembling stage.

Method of manufacturing a disk drive spindle motor

A spindle motor has a tapped hole formed in the end surface of a rotor hub at the center of rotation of the rotor hub. A clamping member presses a disk against a disk holding surface of the rotor hub by a clamp screw threaded in the tapped hole. Since the disk is clamped through a clamping member by threading and tightening one clamp screw, the clamping operation is efficiently carried out and disk imbalance due to the clamping clamp screw is decreased.

Spindle motor

In a spindle motor for a driving a memory disk, a closed space is formed by a sleeve, an end portion of a shaft and a thrust plate. The closed space is connected to outside open space by a connection path, thereby effectively discharging undesirable air in an assembling stage.

Spindle motor for driving memory disk

A cylindrical shielding plate is provided on an inner circumference of the cylindrical recess formed on the bracket of an electric motor of a magnetic disk drive, and an open sector of the stator core is arranged to coincide with the moving direction of read/write head. Or a cylindrical boss is inserted between the stationary shaft and the stator core. Thereby, high frequency electromagnetic noise to the magnetic disk is drastically reduced.

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Yonago, Japan

Akihide Matsuo