Brush holder

Details Brush holder Brush holder

1999-08-23

2001-06-12

Ramirez, Nestor (Department: 2834)

Electrical generator or motor structure

Dynamoelectric

Rotary

C310S239000, C310S242000

Reexamination Certificate

active

06246145

ABSTRACT:

TECHNICAL FIELD
The present invention relates to improvements to a brush holder assembly for use in a direct-current electric motor.
BACKGROUND ART
An example of a conventional brush holder assembly for use in a direct-current electric motor is disclosed in Japanese Utility Model Laid-Open No. HEI 3-18658. The construction of the conventional brush holder assembly will be explained below with reference to
FIGS. 4
to
7
.
The brush holder assembly comprises a pair of negative-side brush holder frames
2
a
,
2
b
and a pair of positive-side brush holder frames
3
a
,
3
b
fastened to a base
4
.
The base
4
is a steel plate formed into an annulus having a central opening
4
a
being designed to allow passage of a commutator
1
. A plurality of positioning holes
20
are disposed on the base
4
. In addition, a plurality of tabs
21
are provided by press working part of the base
4
.
Furthermore, the brush holder frames
2
a
,
2
b
,
3
a
,
3
b
are molded from electrically-insulating synthetic resin.
Brush receiving recesses
22
are disposed in brush holder frames
2
a
,
3
b
, respectively, so as to extend from a first end towards a second end without penetrating the second end. Furthermore, pairs of flanges
23
are disposed such that each extends outwards from the bottom end on either side. Fastening slots
24
are disposed on each pair of flanges
23
. Furthermore, a lead outlet groove
25
is disposed on one side so as to extend from the first end towards the second end and join the brush receiving recess
22
to the outside. Furthermore, a plurality of protrusions
26
for positioning are disposed on the bottom surface. In addition, a plurality of radiator openings
27
are provided.
On the other hand, brush holder frames
2
b
,
3
a
are constructed similarly to brush holder frames
2
a
,
3
b
above, except that the lead outlet groove
25
is disposed on the opposite side of each so as to extend from the first end towards the second end and join the brush receiving recess
22
to the outside.
The brush holder frames
2
a
,
2
b
,
3
a
,
3
b
are fastened onto the base
4
by inserting the protrusions
26
into the positioning holes
20
so as to allow the tabs
21
to pass through the fastening slots
24
and bending the tips of the tabs
21
projecting from the fastening slots
24
. At that point, the brush holder frames
2
a
,
2
b
,
3
a
,
3
b
are fastened to the base
4
such that the open ends of the brush receiving recesses
22
each face the central opening
4
a
of the base
4
and the axes of the brush receiving recesses
22
pass through the central axis of the central opening
4
a
of the base
4
. By inserting the protrusions
26
into the positioning holes
20
, movement of the brush holder frames
2
a
,
2
b
,
3
a
,
3
b
in the radial direction and in the direction of rotation is controlled. Furthermore, the tabs
21
securing each of the brush holder frames are bent in mutually opposite radial directions, preventing the brush holder frames from dislodging longitudinally.
Negative-side brushes
5
a
,
5
b
are inserted into the brush receiving recesses
22
of brush holder frames
2
a
,
2
b
, respectively, by passing negative-side leads
7
a
,
7
b
through the lead outlet grooves
25
. Similarly, positive-side brushes
6
a
,
6
b
are inserted into the brush receiving recesses
22
of brush holder frames
3
a
,
3
b
, respectively, by passing positive-side leads
8
a
,
8
b
through the lead outlet grooves
25
. The brushes
5
a
,
5
b
,
6
a
,
6
b
are placed in contact with the outer circumferential surface of the commutator
1
inserted through the central opening
4
a
of the base
4
by the force of brush springs
9
disposed within each of the brush receiving recesses
22
.
The negative-side leads
7
a
,
7
b
connected to the negative-side brushes
5
a
,
5
b
are grounded by connection to the base by welding, etc. On the other hand, the positive-side leads
8
a
,
8
b
connected to the positive-side brushes
6
a
,
6
b
are connected to a power source (not shown) by means of a connector
11
. The positive-side leads
8
a
,
8
b
are covered with insulating tubing
10
to prevent electrical short-circuiting with the base
4
.
This brush holder assembly is mounted onto an end bracket of a direct-current electric motor using screw holes
12
disposed in the base
4
.
In the conventional brush holder assembly, as shown in
FIG. 4
, a negative-side leads
7
a
passes out of a negative-side brush holder frame
2
a
in a counter-clockwise direction, and a negative-side lead
7
b
passes out of a negative-side brush holder frame
2
b
in a clockwise direction.
On the other hand, a positive-side lead
8
a
passes out of a positive-side brush holder frame
3
a
in a clockwise direction, and a positive-side lead
8
b
passes out of a positive-side brush holder frame
3
b
in a counter-clockwise direction. In other words, as shown in
FIG. 5
, the lead outlet grooves
25
in brush holder frames
2
a
,
3
b
are disposed in the left-hand side viewed from one end (the front), and as shown in
FIG. 6
, the lead outlet grooves
25
in brush holder frames
2
b
,
3
a
are disposed in the right-hand side viewed from one end (the front).
Thus, two types of brush holder frames having lead outlet grooves in different positions have been used in conventional brush holder assemblies, requiring two types of mold for forming the brush holder frames, and costs could not be reduced. Furthermore, it has been necessary to store the molded brush holder frames separately until assembly is performed. Furthermore, it has been necessary to check the position of the lead outlet grooves and select the brush holder frames during assembly, and there have been cases of operations failure due to incorrect assembly.
DISCLOSURE OF THE INVENTION
The present invention aims to solve the above problems and an object of the present invention is to provide a brush holder assembly enabling costs to be reduced and the occurrence of operations failure due to incorrect assembly to be prevented beforehand by constructing the brush holder frames so that they can be used regardless of the direction in which the leads are to pass out.
The brush holder assembly according to the present invention comprises:
a base made of steel plate having a passage for the insertion of a commutator;
a plurality of brush holder frames each made of insulating synthetic resin and each formed in the same shape having a brush receiving recess disposed therein so that the brush receiving recess has an opening at a first end and a closure at a second end and lead outlet grooves disposed in both sides thereof so that each has an opening at the first end, extends from the first end towards the second end and joins the brush receiving recess to the outside, the brush holder frames being secured to the base such that the openings of the brush receiving recesses face the passage and the axes of the brush receiving recesses are directed towards the central axis of the passage;
a plurality of brushes inserted into each of the brush receiving recesses by passing leads attached to the side thereof through one of the lead outlet grooves in the brush holder frames; and
a plurality of brush springs disposed within each of the brush receiving recesses of the brush holder frames for applying force to the brushes in the direction of the central axis of the passage.


REFERENCES:
patent: 5148072 (1992-09-01), Shiroyama
patent: 5717271 (1998-02-01), Aoki et al.
patent: 5773907 (1998-06-01), Rubinchik
patent: 6005323 (1999-12-01), Morimoto et al.
patent: 6144134 (2000-11-01), Lin
patent: 58-70073 (1983-05-01), None
patent: 63-83969 (1988-06-01), None
patent: 3-18658 (1991-02-01), None
patent: 5-60154 (1993-08-01), None
patent: 7-322559 (1995-12-01), None

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