Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
2001-06-22
2004-07-27
Tamai, Karl (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310S051000, C310S242000, C310S244000, C310S249000, C310S071000, C310S0400MM
Reexamination Certificate
active
06768243
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a small-size motor and, more particularly, to a small-size motor capable of being directly fitted with electric elements such as capacitors for driving electrical equipment, household electrical appliances, or the like.
BACKGROUND ART
A small-size motor used for driving electrical equipment, household electrical appliances, or the like is desired to be directly fitted with electric elements such as a capacitor, a diode, and a choke coil, in a motor case cover made of synthetic resin. For example, chip capacitors are attached to reduce electrical noise. However, the case cover of the conventional small-size motor has an insufficient space for installing a required number of electric elements.
FIG. 6
is a view of a case cover of a small-size motor having a conventional construction, which is viewed from the inside of the motor (see Japanese Utility Model Application Laid-Open No. 4-121384).
FIG. 7
is a partially sectional view of the case cover shown in
FIG. 6
, in which the case cover is cut at a capacitor portion. In
FIGS. 6 and 7
, a case cover
11
made of synthetic resin is provided with a pair of input terminals
26
and a pair of brush arms
12
. Each of carbon brushes
4
is fixed respectively at a free end of the brush arm
12
connected electrically to the input terminal
26
.
Each of a pair of capacitors
15
is inserted in a void formed in the case cover
11
. An electrode
27
on one side of the capacitor
15
is in contact with the extension
26
a
of the input terminal
26
, and on the other hand, a substantially U-shaped spring member
25
is in contact with an electrode
28
on the other side of the capacitor
15
. Thus, not only electrical connection can be ensured, but also the capacitors
15
can be fixed firmly in a void in the case cover
11
by being pressed transversely. The spring member
25
also can ensure electrical connection with a metallic case when the case cover
11
is fitted to the case.
By the capacitor installation construction as shown in the figures, the need for soldering work and lay-out work for connection wires, which necessarily accompany the connection work for electric elements, can be eliminated. Thus, the electric elements such as capacitors are securely fixed in a limited space, and on the other hand, electrical connection can be provided with high reliability. However, although two electric elements can be installed in the case cover by the construction shown in the figures, three electric elements cannot be installed.
FIG. 8
is a view for illustrating the need for installing three electric elements. FIG.
8
(A) is a schematic electrical connection diagram for a small-size motor having a conventional construction as shown in FIG.
6
. In
FIG. 8
, reference character M denotes a motor, and C
1
to C
3
denote capacitors. A power source is connected to rotor windings of the motor M via brushes from the input terminals, and also is connected respectively to one electrode of each of the two capacitors C
1
and C
2
. The other electrodes of the two capacitors C
1
and C
2
are connected to each other, and grounded to the metallic case of the motor from the connection point. In the conventional configuration shown in FIG.
8
(A), since only two capacitors C
1
and C
2
can be installed, the configuration as shown in the FIG.
8
(A) is unwillingly adopted, and therefore the electrical noise reducing effect is insufficient on the low-frequency band.
DISCLOSURE OF THE INVENTION
Contrarily, if three capacitors can be installed to provide electrical connection, the wiring can be accomplished as shown in FIG.
8
(B). Specifically, in addition to the wiring shown in FIG.
8
(A), a third capacitor C
3
can be connected across both input terminals. It has been known that such a circuit is superior in terms of the electrical noise reducing effect on the low-frequency band.
Accordingly, an object of the present invention is to provide a small-size motor in which a sufficient space is secured in a motor case cover made of synthetic resin so that three electric elements such as chip capacitors can be incorporated together with their wiring and support arrangement.
The small-size motor in accordance with the present invention includes a metallic case
1
having a bottomed hollow cylindrical shape, fitted with a magnet
2
on the inner peripheral surface thereof; a case cover
11
made of synthetic resin, mounted so as to close an opening of the case
1
; and a rotor fitted with a laminated core
22
, windings
23
wound on the laminated core
22
, and a commutator
24
on a shaft
21
. The case cover
11
supports a pair of brush units each of which has a brush arm
12
fitted with a brush
4
and a brush base
13
fixed and connected to the brush arm
12
. The case cover
11
is formed with three voids to contain three electric elements such as chip capacitors. A first electric element is fixed mechanically between the paired brush units in a first void to be connected electrically. The remaining two second and third electric elements are located on both sides of the first electric element and are pressed on the brush base in the motor shaft direction by a body earth terminal
14
in second and third voids, so that the body earth terminal
14
is fixed to the case cover
11
, whereby the two electric elements are fixed mechanically and connected electrically.
Also, the first electric element is fixed mechanically and connected electrically between both fixing portions
8
via a metallic spring (U-shaped spring
18
), each of which connects the brush arm
12
of each of the paired brush units with the brush base
13
. One electrode of each of the second and third electric elements is mounted on the side face of a brush base end portion
9
, and the other electrode thereof is pressed by the body earth terminal
14
.
Further, the body earth terminal
14
, which is formed by being stamped out of a metal plate and being bent, includes an element pressing portion
16
for pressing the electric element, a body earth portion
17
, and a holding portion
20
, and is installed so as to cover a case cover fitting portion
7
fitted to the case
1
in such a manner that the case cover fitting portion
7
is held by the body earth portion
17
from the outside and by the holding portion
20
from the inside.
Thus, three electric elements such as chip capacitors can be incorporated together with their wiring and support arrangement.
REFERENCES:
patent: 4845393 (1989-07-01), Burgess et al.
patent: 5281876 (1994-01-01), Sato
patent: 5563462 (1996-10-01), Strobl et al.
patent: 5717270 (1998-02-01), Lau et al.
patent: 5734212 (1998-03-01), Uffelman
patent: 6580194 (2003-06-01), Mizutani et al.
patent: 415367 (1991-03-01), None
patent: 544404 (1993-06-01), None
patent: 58-131165 (1983-09-01), None
patent: 60131058 (1985-07-01), None
patent: 62-95485 (1987-06-01), None
patent: 4-121384 (1992-10-01), None
patent: 07099754 (1995-04-01), None
patent: 7-194063 (1995-07-01), None
patent: 2001008414 (2001-01-01), None
patent: 2002315274 (2002-10-01), None
Kimura Hiroshi
Yamazaki Hiroshi
Comas Yahveh
Mabuchi Motor Co. Ltd.
McGlew and Tuttle , P.C.
Tamai Karl
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