Nidec Corporation

Masanobu Chuta

Hiroshi Matsumoto

Harushige Osawa

Eiji Miyamoto

Koji Tomita

Hiromi Iida

Junko Satake

Isao Kaneda

Tetsuya Tsuji

Asao Yazaki

The present invention discloses a disk drive motor comprising a rotor having an annular space formed therein coaxially with the axis of rotation, and balancing member accommodated in the annular space and capable of changing its mass distribution circumferentially along the circle of the annular space. In case of any imbalanced rotation occurring during the rotation, the balancing member temporarily gather to a portion of the annular space where the mass imbalance is taking place. However, when the motor speed exceeds the value at which resonance takes place due to coincidence between the frequency of the vibration of the balancing member and the natural frequency of the motor, the balancing members move to a position symmetrical with the point of mass imbalance to eliminate the mass imbalance, thereby suppressing the run-out.

Disk drive motor

A spindle motor comprises a stationary shaft, a rotor hub rotatably mounted by ball bearings to the stationary shaft, and annular sealing members disposed between the outer surface of the stationary shaft and the inner side of the rotor hub axially outwardly of the ball bearings. The sealing member is directly fitted onto the outer race of the corresponding ball bearing. The outer race of each ball bearing is high precision finished so that the sealing member is definitely coaxial with the stationary shaft regardless of the finishing accuracy on the inner side of the rotor hub. Accordingly, the radial distance between the inner side of the sealing member and the outer surface of the stationary shaft can be minimized with high precision offering an excellent labyrinth effect.

Spindle motor with seal structure

A brushless motor comprising a stator core having a plurality of tooth portions disposed peripherally at intervals, coils wound in a required manner on a plurality of tooth portions, an annular rotor magnet disposed in opposition to the stator core and having N poles and S poles alternately disposed, and a position detecting sensor for detecting the rotating angular position of the rotor magnet. The stator core is formed by laminating an anisotropic steel sheet in which the easily magnetizable axis of the crystal is in a specific direction.

Brushless motor

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Oumihachiman, Japan

Masanobu Chuta