Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
2000-01-26
2001-09-25
Waks, Joseph (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310S239000, C029S597000, C029S826000
Reexamination Certificate
active
06294850
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a small-sized motor and particularly to a small-sized motor which realizes stable bearing alignment through use of a metallic casing cover and which secures insulation outside the casing cover in order to enable direct attachment of an electrical element, such as a capacitor, to the motor.
BACKGROUND ART
In the case of a small-sized fan motor used in a drier or the like, an electrical element, such as a capacitor, diode, or choke coil, is required to be attached direct to the outer surface of the motor. However, since the end bell of a conventional small-sized motor is designed such that a metallic casing cover is exposed to the outside of the motor, an electrical element cannot be attached to the outer surface of the motor unless insulation is provided between the electrical element and the casing cover.
FIG. 4
shows such a conventional small-sized motor having a metallic casing cover, wherein the overall structure of the motor is shown on the leftmost side with the upper half of the motor shown in cross section; an end bell formed of a synthetic resin and removed from the casing is shown on the right side thereof; and a casing cover is shown on the rightmost side. Magnets
1
are attached to the inner surface of a casing
2
, which is formed of a metallic material and into a closed-bottomed cylindrical shape. A casing cover
5
is fitted to the casing
2
so as to close an opening portion of the casing
2
. A bearing
6
for a shaft
7
is mounted at a central portion of the casing cover
5
. The other end of the shaft
7
is supported by a bearing
3
, which is disposed at the center of a bottom portion of the casing
2
having a closed-bottomed cylindrical shape.
The shaft
7
is equipped with a laminated core
8
, windings
9
wound around the laminated core
8
, and a commutator
10
, thereby forming a rotor of the small-sized motor. Brushes in contact with the commutator
10
are supported by the end bell
4
. Input terminals
11
connected to the brushes extend through the casing cover
5
and are projected to the outside for electrical connection.
As described above, in the conventional small-sized motor, the metallic casing cover
5
is located outermost, and the end bell
4
—which is formed of a synthetic resin and supports the brushes, the input terminals
11
, and the like—is disposed on the inner side of the casing cover
5
and is fitted into the opening portion of the casing
2
. Since the bearing
6
is accommodated in the center portion of the metallic casing cover
5
, stable bearing alignment is secured. However, when an electrical element is to be attached to the outer surface of the metallic casing cover
5
, it becomes necessary to provide a cover formed of synthetic resin, paper, or the like for insulting the electrical element from the casing cover
5
.
Instead of being formed of metal, the casing cover
5
may be formed from a synthetic resin through injection molding in which the casing cover
5
is molded integrally with the end bell to thereby secure insulation. In this case, however, the accuracy of the casing cover
5
becomes inferior to that of a metallic casing cover produced through cutting work. Therefore, the accuracy in alignment of bearings disposed on the opposite sides of the motor deteriorates, so that the clearance between the shaft and each of the bearings must be increased. However, when the clearance is increased, the shaft hits the bearings due to electromagnetic force of the motor and other causes, resulting in generation of clearance noise. In order to solve the above-described problem to thereby decrease clearance noise, a spherical bearing may be employed as a self-aligning mechanism. In this case, since a part for supporting the bearing becomes necessary, cost increases.
DISCLOSURE OF THE INVENTION
An object of the present invention is to provide a small-sized motor which maintains the advantageous feature of a metallic casing cover to thereby secure stable bearing alignment and which provides insulation outside the motor to thereby enable attachment of an electrical element to the motor without use of any additional insulation means.
A small-sized motor of the present invention comprises a metallic casing
2
having a closed-bottomed cylindrical shape and including a magnet
1
attached to an inner surface thereof; a casing cover
5
fitted to the casing
2
so as to close an opening portion of the casing
2
; and a rotor including a shaft
7
, a laminated core
8
mounted on the shaft
7
, windings
9
wound around the laminated core
8
, and a commutator
10
mounted on the shaft
7
. The motor further comprises an insulation holder
16
which is integrally molded from a synthetic resin. The insulation holder
16
comprises a cover portion
13
for covering the casing cover
5
from the outer side thereof, and a pair of brush holders
12
which project from the cover portion
13
into the interior of the motor, while passing through cut portions formed in the casing cover
5
. Each of the brush holder
12
supports a brush arm
17
and an input terminal
11
connected thereto. The brush arm
17
supports a carbon brush
18
. Bearings
3
and
6
for the shaft are respectively supported at the center of the bottom portion of the casing
2
and at the center of the casing cover
5
. Thus, stable bearing alignment is realized, and an insulating property can be imparted to the outer surface of the motor.
Further, a pair of magnet pressers
14
can be formed integrally with the insulation holder
16
such that the magnet pressers
14
project into the interior of the motor via the cut portions formed in the casing cover
5
, to thereby axially position the magnet
1
.
REFERENCES:
patent: 3654504 (1972-04-01), Susdorf et al.
patent: 3735172 (1973-05-01), Battaglia et al.
patent: 3745393 (1973-07-01), Spors
patent: 4626178 (1986-12-01), Terumoto
patent: 4965478 (1990-10-01), Kobayashi et al.
patent: 5070269 (1991-12-01), Tamaki et al.
patent: 5089735 (1992-02-01), Sawaguchi et al.
patent: 5280210 (1994-01-01), Kress et al.
patent: 5481150 (1996-01-01), Tanaka et al.
patent: 5608280 (1997-03-01), Tamemoto et al.
patent: 6160329 (2000-12-01), Ng
patent: 0510 984 A1 (1992-10-01), None
patent: 2000224815 (1999-01-01), None
Furuya Kenji
Yui Toshiya
Mabuchi Motor Co. Ltd.
McGlew and Tuttle , P.C.
Waks Joseph
LandOfFree
Small-sized motor does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Small-sized motor, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Small-sized motor will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2509471