Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
2001-07-23
2003-03-04
Ramirez, Nestor (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C318S089000
Reexamination Certificate
active
06528922
ABSTRACT:
FIELD OF THE INVENTION
The invention relates generally to miniature motors used in, for example, toys; audio and video equipment, and automotive electrical appliances, hand tools and other motor-driven devices. More particularly, the invention relates to an end cover plate and brush base for a motor casing of a miniature motor.
BACKGROUND OF THE INVENTION AND RELATED ART STATEMENT
FIG. 1
is a miniature motor
10
having a metallic cylindrical housing
12
. The housing
12
may be formed of mild steel and have a hollow tubular section
14
and an integral bottom
16
. The opposite end
30
of the housing is open to receive a brush base and cover plate at one end of the tubular section. Within the housing are fixed a pair of opposite permanent magnets
18
, each of which have an arc shape to match the inner wall of the housing. The magnets form between them a volume in the housing for a rotor
20
. The rotor includes a cylindrical armature
22
coaxially mounted on a rotor shaft
24
. The rotor shaft
24
extends through the opposite ends of the housing
12
.
Bearings
26
are mounted to rotatably support the shaft in the ends of the housing. The bottom
16
of the motor housing has an integral flange
28
, into which is press-fitted a bearing
26
to support one end of the rotor shaft
24
. The opposite end
30
of the housing has an open cylindrical base which receives a brush base
32
and cover plate
34
which are assembled together to fit in the open end
30
of the housing.
The cover plate
34
fits over the base, and the cover plate and brush base fit into the motor housing. The open edge of the housing is crimped onto the plate. The cover plate
34
has a flange
36
to support a bearing
26
which supports an end of the rotor shaft
24
. The flange
36
and bearing
26
of the cover plate
34
(when inserted in the motor housing) are coaxially aligned with the flange
28
and bearing
26
on the bottom section
16
of the motor housing so that the rotor shaft is held in coaxial alignment with the motor housing
12
.
The brush base
32
supports a pair of brush arms
38
which provide an electrical connection between an external electrical contact
40
of the motor and the armature
22
of the rotor
20
. The brush arms are generally strips of copper having a first end fixed to the periphery of the brush base
32
and an opposite, free end on which is mounted a brush
42
. The brush arms are attached to opposite sides of the brush base. The brushes on the arms face each other at the axis of the motor. When inserted in the housing, the brushes are in slidable contact with the commutator
44
on the rotor shaft
24
. The commutator provides an electrical contact between the wiring of the armature
22
and the brushes.
The external contacts
40
of the brush arms provide direct electrical current (D.C.) through the brushes and the commutator to the windings in the armature
22
. Electrical current flowing through the armature creates an alternating magnetic field within the housing that interacts with the magnetic field of the permanent magnets
18
. This interaction of magnetic fields creates a force that rotates the rotor
20
. This rotation drives the rotor shaft
24
to provide a mechanical rotational output power source from the rotor. The rotor shaft
24
extends through the bottom
16
of the housing to provide a mechanical power output to drive a gear box or other device.
Conventional cover plates
34
are cylindrical discs having embedded recesses which fit into matching slots in the brush base
32
and/or grooves in the end
30
of the housing. Forming a motor plate having recesses, brush bases having slots and machining the motor housing to have the grooves needed to match the cover plate and/or base adds to the complexity and cost of miniature motors. Miniature motors tend to be a relatively-low cost component of toys and other equipment. Accordingly, it is important that manufacturing costs for making these motors be minimized.
SUMMARY OF THE INVENTION
The invention is intended to overcome the problems inherent with prior miniature motors having complicated brush bases, and motor plates. Specifically, the invention relates to a simplified construction of a motor housing, brush base and motor plate.
The simplified construction features include a motor housing having an outer end which has a smooth circular edge, that does not require the cutting of slots into the edge. Minimal machining may be applied to the edge to polish an outer ring of the housing and to machine a lip to engage the brush base. The brush base also has a simplified construction and formed by injection molded plastic. Moreover, the brush base has several features which facilitate the assembly of the motor housing including a collar and flange that fit easily into the motor housing to fix the position of the brush base inside the housing. The cover plate, which may be a simple metal stamp construction, fits directly onto a planar region of the brush base.
REFERENCES:
patent: 3445692 (1969-05-01), Kato
patent: 3584248 (1971-06-01), Higashimo
patent: 3654504 (1972-04-01), Susdorf
patent: 4037316 (1977-07-01), Stoll
patent: 4041339 (1977-08-01), Huber et al.
patent: 4127785 (1978-11-01), Noguchi
patent: 4152614 (1979-05-01), Noguchi et al.
patent: 4177396 (1979-12-01), Wang
patent: 4293789 (1981-10-01), King
patent: 4315237 (1982-02-01), Middleman et al.
patent: 4728835 (1988-03-01), Baines
patent: 4746829 (1988-05-01), Strobl
patent: 4795079 (1989-01-01), Yamada
patent: 4801833 (1989-01-01), Dye
patent: 4853576 (1989-08-01), Mayumi
patent: 5010264 (1991-04-01), Yamada et al.
patent: 5089801 (1992-02-01), Chan et al.
patent: 5140205 (1992-08-01), Baines
patent: 5294851 (1994-03-01), Tajima et al.
patent: 5294852 (1994-03-01), Straker
patent: 5434460 (1995-07-01), Mabuchi et al.
patent: 5598045 (1997-01-01), Ohtake et al.
patent: 5600193 (1997-02-01), Matsushima et al.
patent: 5620311 (1997-04-01), Wetzel
patent: 5633542 (1997-05-01), Yuhi et al.
Physical sample—1 sheet of pictures of Mabuchi Miniature Motor (photos of actual motors shown and discussed at interview).
Physical sample—1 sheet of pictures of Johnson Electric Miniature Motor (photos of actual motors shown and discussed at interview).
Hanh Nguyen
New Bright Industrial Co. Ltd.
Nixon & Vanderhye P.C.
Ramirez Nestor
LandOfFree
Motor housing having simplified cover plate and brush base does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Motor housing having simplified cover plate and brush base, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Motor housing having simplified cover plate and brush base will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3056903