US 6,205,110 B1Granted

Disk drive motor

AssigneeNidec Corporation

InventorsEiji Miyamoto, Harushige Osawa, Masanobu Chuta

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Abstract

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.

Claims6

Dependent claims

A disk drive motor comprising:

a shaft;
a disk-shaped rotor fixed on one end of the shaft and having an annular projection surrounding the shaft, the rotor having an annular groove on the bottom of the annular projection;
a base plate having a sleeve member;
a bearing means located in the sleeve member and interposed between the shaft and the sleeve member for rotatably supporting the shaft;
a yoke including a plate portion having a central opening and a circular depending portion depending from radially outward portion of the plate portion, the yoke being fixed to the annular projection of the rotor at the inner edge of the central opening so as to be in contact with the upper surface of the plate member and the lower surface of the rotor to close the opening of the annular groove and form a closed annular space;
a rotor magnet secured on the inner peripheral surface of the circular depending portion of the yoke;
a stator disposed on the base plate so as to oppose the rotor magnet;
and
a balancing member movably located in the annular space.

6 more elements

Dependencies are inferred from the claim text.

Facts

Application: 09/103,727Filed 23 Jun 1998
Priority: JP 9-18453125 Jun 1997
Granted: 20 Mar 2001
Term ends: Not estimatedThe source records don’t support an estimate.

Classification5 codes

F16F 15/363
Operating automatically , i.e. where, for a given amount of imbalance, there is movement of masses until balance is achieved: using rolling…
G11B 19/2009
Driving; Starting; Stopping; Control thereof: turntables, hubs and motors for disk drives; Mounting of motors in the drive
G11B 19/2027
Turntables, hubs and motors for disk drives; Mounting of motors in the drive: turntables or rotors incorporating balancing means; Means for…
F16F
Springs