Brush holder

Details Brush holder Brush holder

1999-08-02

2001-08-07

Nguyen, Tran (Department: 2834)

Electrical generator or motor structure

Dynamoelectric

Rotary

C310S242000

Reexamination Certificate

active

06271615

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. 7
to
11
.
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 tabs
21
are disposed on the base
4
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 a central portion of 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 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 passing the tabs
21
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
. The tabs
21
securing each of the brush holder frames are bent in mutually opposite radial directions, preventing the brush holder frames from dislodging in the axial direction.
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
and forming a pigtail 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
and forming a pigtail 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 on an end bracket of direct-current electric motor using screw holes
12
disposed in the base
4
.
In a conventional brush holder assembly, the positive-side brush holder frames
3
a
,
3
b
are secured to the base
4
by passing tabs
21
disposed on the base
4
through the fastening slots
24
disposed in the flanges
23
extending outwards from central portions of the bottom end on either side thereof and bending the tips of the tabs
21
projecting from the fastening slots
24
. Thus, as shown in
FIG. 11
, the tabs
21
and the leads
8
a
,
8
b
are in close proximity. Moreover, as the brushes
6
a
,
6
b
are worn down by the commutator
1
, they are moved towards the commutator
1
by the force of the brush springs
9
. With the movement of the brushes
6
a
,
6
b
towards the commutator
1
, the leads
8
a
,
8
b
move within the outlet grooves
25
towards the commutator
1
.
During operation of the direct-current electric motor, the leads
8
a
,
8
b
are on the positive electrode side, and the base
4
, including the tabs
21
, is on the negative electrode side. Thus, it has been necessary to cover the leads
8
a
,
8
b
with the insulating tubing
10
because there is a risk that the leads
8
a
,
8
b
and the tabs
21
will touch and short circuit electrically. For that reason, a problem has been that because of the necessity to have the tubing
10
, an operation for covering the leads
8
a
,
8
b
with the tubing
10
has been required, making it difficult to reduce costs.
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 not requiring tubing to cover the positive-side leads to prevent electrical short circuiting because electrical short circuiting incidents in the positive-side leads are prevented beforehand.
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 and having a plurality of tabs for fastening disposed on a main surface thereof,
a plurality of brush holder frames each made of insulating synthetic resin and comprising a brush receiving recess having an opening at a first end and a closure at a second end, a lead outlet groove disposed in one side so as to extend from the first end towards the second end and join the brush receiving recess to the outside, and flange portions each extending outwards from the bottom end on either side, the brush holder frames being disposed on the base such that the openings of the brush receiving recesses face the passage and the brush receiving recesses are directed towards the central axis of the passage, and being secured to the base by bending the tips of the tabs;
at least one positive-side brush inserted into the brush receiving recess and held by a brush holder frame by passing a positive-side lead attached to the side thereof through the lead outlet groove in the brush holder frame;
at least one negative-side brush inserted into the brush receiving recess and held by a brush holder frame by passing a negative-side lead attached to the side thereof out through the lead outlet groove in the brush holder frame; and
a plurality of brush springs disposed within each of the brush receiving recesses of the brush holder frames for applying force to the positive-side and negative-side brushes in the direction of the central axis of the passage,
wherein the tabs for securing the brush holder frames holding the positive-side brushes are disposed in-positions where the tabs will not contact the positive-side leads.


REFERENCES:
patent: 5148072 (1992-09-01), Shiroyama
patent: 5397952 (1995-03-01), Decker et al.
patent: 5939812 (1999-08-01), Wetzel
patent: 6005323 (1999-12-01), Morimoto et al.
patent: 58-70073 (1983-05-01), None
patent: 62-95474 (1987-06-01), None
patent: 3-18658 (1991-02-01), None
patent: 6-74079 (1994-10-01), None
patent: 5-60154 (1996-08-01), None

Affiliated with

Also associated with

Rating

Brush holder does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Brush holder, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Brush holder will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2467298