Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
2000-03-31
2001-08-21
Nguyen, Tran (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310S216055, C310SDIG006
Reexamination Certificate
active
06278214
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a motor, a method of fabricating a motor and a rotary body apparatus, further in details, relates to a motor capable of solidly supporting a stator coil with high rigidity and having small vibration and noise, a method of fabricating a motor and a rotary body apparatus.
Conventionally, in a rotary body apparatus such as a rotary polygonal face mirror apparatus of a laser beam printer or the like or HDD (hard disk drive), there is used a motor as shown by FIG.
7
.
The motor shown by
FIG. 7
is provided with a base
110
having a fitting portion (supporting member)
110
a
projected in a circular ring shape, a hub shaft
130
extended with a shaft
131
from the center of a hub
132
in a circular disk shape and a bearing ring
152
fixedly attached to a lower end portion of the shaft
131
.
The bearing ring
152
is inserted into the fitting portion
110
a
of the base
110
, thereby, the hub shaft
130
is rotatably supported by the base
110
.
A circular ring portion
133
is extended from a peripheral edge portion of the hub shaft
130
in a lower direction and a rotor magnet
160
is fixed to an inner peripheral wall of the circular ring portion
133
.
A stator coil
140
is fixed to an outer peripheral face of the fitting portion
110
a.
As shown by
FIG. 8
, the stator coil
140
comprises a sheet-like yoke
141
laminated with a single or a plurality of sheets having the same shape and coils
142
formed by winding lead wires at the yoke
141
. The yoke
141
comprises a mounting portion in a circular ring shape and a plurality of winding portions extended from the mounting portion outwardly in the diameter direction and is fixed to the fitting portion
110
a
by inserting the fitting portion
110
a
to a hollow portion of the mounting portion. The coil
142
is formed by winding lead wires around the winding portion.
Further, rotary magnetic field is formed by the stator coil
140
and the rotor magnet
160
is urged by the rotary magnetic field to thereby rotate the hub shaft
130
.
The base
110
is fixed to a chassis of a main body apparatus of a printer or HDD.
Such a motor is used in a quiet place such as an office building or the like and therefore, it is requested to restrain vibration as less as possible and prevent noise from being emitted in driving to rotate the motor. Further, particularly in HDD, by high density formation of a hard disk in recent years, fineness is requested in a position of reading data by a magnetic head and also in this regard, there is requested a motor restraining vibration as less as possible, providing high rigidity and rotating with excellent rotational accuracy.
As a method of restraining vibration, there is conceived a technology of forming the fitting portion
110
a
projected from the base
110
separately and fixing the fitting portion
110
a
by adhering or fitting. According to the technology, vibration from the stator coil
140
is transmitted to the base
110
after having been attenuated and accordingly, vibration from the stator coil
140
is reduced.
Now, according to the conventional motor, mentioned above, either of an outer peripheral face of the fitting portion
110
a
provided to the base
110
(both of the fitting portion
110
a
integrated to the base
110
and the fitting portion
110
a
separately fixed thereto) and an inner peripheral face of the mounting portion of the yoke is provided with a sectional shape in view from the axial direction in a circular shape. The reason is that the shape is suitable for lathe machining since machining of the fitting portion or the yoke is carried out by the lathe machining and the integrating performance of the stator of the motor for supporting the rotor portion (hub shaft) is excellent.
Further, in order to accurately rotate the rotor portion, there is needed high durability against load applied in high speed rotation and accordingly, in any case, it is necessary to machine to form these parts with excellent roundness and to fit and fix these parts.
However, actually, by influence of chucking in a lathe, it is not possible to machine either of the outer peripheral face of the fitting portion and the inner peripheral face of the mounting portion of the yoke such that sections of these become completely round (complete roundness) and actually, these parts are machined in a irregular circle including the roundness.
Further, when the fitting portion having the outer peripheral face of such an irregular circular shape, is mounted with the mounting portion of the yoke similarly having an irregular circular shape, face contact is not constituted, and in either of the circumferential direction and the axial direction, there is brought about a state in which contact portions and separated portions are irregularly arranged.
Therefore, there are produced portions where external force is received by gaps, the rigidity is deteriorated and when the motor is driven to rotate, the motor is liable to deviate by load of rotation to thereby cause an increase in vibration and noise. Further, the deviation is difficult to deal with since the deviation is caused irregularly.
SUMMARY OF THE INVENTION
The invention has been carried out to resolve the above-described problem and it is an object thereof to provide a motor capable of solidly supporting a stator coil with high rigidity and having inconsiderable vibration and noise, a method of fabricating a motor and a rotary body apparatus.
The invention achieves the above-described object by providing a motor comprising a base, a supporting member in a column-like shape erected on the base, a yoke having a hollow portion at least one end of which communicates with outside, the hollow portion being inserted by the supporting member and coaxially fixed to the supporting member, coils formed by winding lead wires at a plurality of locations of the yoke for generating a rotary magnetic field, a rotor member coaxially with and rotatably supported by the supporting member, and a rotor magnet fixed to the rotor member and urged by the rotary magnetic field for rotating the rotor member, wherein at least one of an inner peripheral face portion of the yoke and an outer peripheral face portion of the supporting member comprises contact portions linearly projected to other thereof and brought into contact with the other at three or more locations in a circumferential direction thereof and separated portions separated from the other and opposed to the other among the contact portions.
According to the motor of the invention, the contact portions projected linearly at the three or more locations in the circumferential direction are arranged at least either of the inner peripheral face portion of the yoke and the outer peripheral face portion of the supporting member. Further, when the supporting member is inserted into the yoke by press fitting, the contact portions are widened toward the separated portions to crush to deform in very small amounts in accordance with the shape of the outer peripheral face of the supporting member, machining error is corrected and the yoke and the supporting member are brought into close contact with each other at the contact portions with no clearances therebetween.
In this way, according to the invention, the supporting member and the yoke can be brought into contact with each other at the contact portions with certainty. Therefore, contact locations of the supporting member and the yoke can be controlled by positions of arranging the contact portions and vibration or deviation caused in rotational operation can easily be dealt with in view of design.
Further, the supporting member and the yoke are brought into contact with each other linearly at the three or more locations in the circumferential direction and accordingly, in rotational operation the supporting member and the yoke are difficult to be deviated from each other and vibration produced by the deviation can be restrained to reduce.
It is preferable that the contact portions are arranged at equal interva
Goto Hiromitsu
Suzuki Takafumi
Adams & Wilks
Nguyen Tran
Seiko Instruments Inc.
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