Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
2000-03-20
2002-05-07
Nguyen, Tran (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310S089000, C310S091000, C360S099060, C360S099080, C360S098070
Reexamination Certificate
active
06384495
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates generally to a motor, a method of manufacturing the motor and a rotary apparatus equipped with the motor and, more particularly, to a motor which can be assembled with accuracy and which can be manufactured easily and at low cost, and to a method of manufacturing the motor and to a rotary apparatus equipped with the motor.
Conventionally, a motor as shown in
FIG. 6
has been used for a rotary apparatus, such as a rotary polygon mirror apparatus such as a laser beam printer and an HDD drive.
The motor of
FIG. 6
has a base
110
having a fit portion
11
a
in the form of an annular projection, a hub shaft
130
having a shaft
131
extending from a center of a disk-formed hub
132
, and a bearing ring
152
secured to a lower end of the shaft
131
.
The bearing ring
152
is inserted in the fit portion
11
a
so that the hub shaft
130
can be rotatably supported on the base
110
.
A stator coil
140
is fixed on an outer periphery of the fit portion
110
a.
An annular portion
133
extends downward from a peripheral edge of the hub shaft
130
. The annular portion
133
has a rotor magnet
160
fixed on an inner peripheral wall of the annular portion
133
.
The stator coil
140
forms a rotating magnetic field so that the rotor magnet
160
can be excited to rotate the hub shaft
130
.
The base
110
is fixed on a chassis of a main body apparatus, such as a printer or HDD drive.
The motor described above is required to operate with reduced vibration and noise during rotative drive because of its usual use in a calm place, such as an office. Particularly, an HDD drive is required to provide accurate position data reading by a magnetic head, due to recent density increase of hard disks. Thus, there is a need to reduce vibrations as much as possible from this viewpoint.
Furthermore, the stator magnet of the stator coil
140
or the like and the rotor magnet
160
if not aligned in their magnetic centers require increased power consumption to obtain required rotation. Furthermore, this would cause wow and flutter in rotation leading to a cause of vibrational noise. Consequently, there is a necessity of assembling the parts with accuracy to correctly position between the stator magnet and the rotor magnet
160
.
Meanwhile, for a motor for use in an HDD drive, the distance should be kept at a predetermined length between a hard disk to be loaded and a magnetic head. Consequently, it is required to exactly position in height of the hub in order for supporting a hard disk with reference to the base.
In the meanwhile, in the conventional motor as shown in
FIG. 6
, the stator coil
140
is a most serious vibration source. Because the stator coil
140
is mounted on the base
110
, vibration on the stator coil
140
is directly conveyed to the base
110
. The vibration is transmitted through the base
110
onto a main body apparatus, such as a printer or HDD drive, causing noise to the outside. In this manner, the prior art motor involves a problem that vibration is directly conveyed to the outside thus resulting in noise.
Also, in the above motor, the base
110
is fixed with a stator coil
140
and the hub shaft
130
with a rotor magnet
160
. Consequently, the adjustment in height of the base
110
and the hub shaft
130
also determines a positional relationship between the stator coil
140
and the rotor magnet
160
. Due to this, the stator coil
140
and the rotor magnet
160
are almost determined in their magnetic center position during forming the parts. It is accordingly impossible during assembling to adjust an error of mounting the stator coil
140
to the base
110
or an error of attaching the rotor magnet
160
to the hub shaft
130
. Thus, in the above motor, there is a problem that it is difficult to manufacture an precise product with respective positional relationships correctly kept between the base
110
and the hub shaft
130
and between the stator coil
140
and the rotor magnet
160
.
Furthermore, in the above motor the base
110
is fixed with the stator coil
140
and the hub shaft
130
is fixed with the rotor magnet. The motor characteristics (electrical and vibration characteristics, etc.) can be measured first on a final product after assembling the hub shaft
130
on the base
110
. When poor assembly is detected, the product must be scrapped in its entirety, including the expensive base, resulting in a reduction of efficiency and increase in cost.
SUMMARY OF THE INVENTION
The present invention has been made in order to solve the above problems in the conventional art. It is an object of the present invention to provide a motor which operates with reduced noise during driving and which can be manufactured easily, efficiently and inexpensively with accuracy, and to a method of manufacturing the motor and a rotary apparatus equipped with the motor.
The motor of the present invention comprises; a columnar support member; a base formed separate from the support member and having a fit portion in which the support member at one end is fitted; a rotor member rotatably supported coaxially to the support member; a regulating means for regulating a position of the rotor member in an axial direction relative to the support member; a magnet fixed on one of the support member and the rotor member; and a plurality of electromagnets fixed facable to the magnets on the other of said support member and the rotor member to form a rotating magnetic field so that the magnet is excited to rotate the rotor member. This achieves the above object.
In the motor of the invention, the support member is fixed with one of the magnet and the electromagnet, and this support member is formed as a separate member from the base. Due to this, it is possible during driving to avoid transmission, directly from the support member to the base, of vibration caused by attracting and repelling forces due to a magnetic field formed by the stator coil and the magnet or vibration due to deviation in a magnetic field center. Accordingly, noise during driving is reduced.
In the motor of the invention, the magnet is fixed on one of the support member and the rotor member and the electromagnets are fixed on the other, and the support member and rotor member are formed separately from the base. The axial position of the support member relative to the base is determined by a positional relationship between the support member and the base. Also, the axial positions of the magnet and electromagnets are determined by a positional relationship between the support member and the rotor member, regardless of the base. Due to this, it is possible to independently conduct, without mutual affection, axial aligning between the base and the support member and between the electromagnets and the magnet. Accordingly, the motor of the invention can be manufactured easily and with favorable assembling accuracy.
Also, after fixing the electromagnets and magnet on the rotor member and support member, it is possible to align between the base and the rotor member and between the electromagnets and the magnet. Accordingly, it is possible to rectify an error occurring upon fixing the electromagnet and magnet on the rotor member and support member or an error caused in forming the parts. Therefore, the motor of the invention can be manufactured easily and with favored assembling accuracy.
In this manner, manufacture with favorable accuracy and accurate alignment between the electromagnets and the magnet are possible to conduct, making possible to avoid noise to be caused due to deviation in magnetic field center.
In the motor of the invention, the magnet is fixed on one of the support member and the rotor member, and the electromagnets are fixed on the other, wherein the support member and the rotor member are formed separately from the base. Accordingly, it is possible to energize the coil and conduct a test as a motor, such as measurement of electrical and vibration characteristics after fixing the magnet and electromagnets on the support member and rotor member
Goto Hiromitsu
Suzuki Takafumi
Adams & Wilks
Nguyen Tran
Seiko Instruments Inc.
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