U.S. patent application number 14/422456 was filed with the patent office on 2015-08-27 for electric motor.
The applicant listed for this patent is Mitsuba Corporation. Invention is credited to Yoshichika Kawashima, Natsumi Tamura, Teppei Tokizaki.
Application Number | 20150244224 14/422456 |
Document ID | / |
Family ID | 50183367 |
Filed Date | 2015-08-27 |
United States Patent
Application |
20150244224 |
Kind Code |
A1 |
Kawashima; Yoshichika ; et
al. |
August 27, 2015 |
ELECTRIC MOTOR
Abstract
When teeth (12) are allocated in a circumferential direction in
sequence of a U phase, a V phase and a W phase, a forward wound
coil wound on each of the phases is provided as a coil of the U
phase, the V phase and the W phase, and a reverse wound coil wound
on each of the phases is provided as the coil of a -U phase, a -V
phase and a -W phase, the coils are electrically connected between
the neighboring segments in an order of the U phase, the -W phase,
the -W phase, the V phase, the -U phase, the -U phase, the W phase,
the -V phase and the -V phase, and the wire (14) drawn between the
armature core (8) and the commutator (10) is drawn around the
rotation shaft in the same direction.
Inventors: |
Kawashima; Yoshichika;
(Kiryu-shi, JP) ; Tokizaki; Teppei; (Kiryu-shi,
JP) ; Tamura; Natsumi; (Kiryu-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Mitsuba Corporation |
Gunma |
|
JP |
|
|
Family ID: |
50183367 |
Appl. No.: |
14/422456 |
Filed: |
August 23, 2013 |
PCT Filed: |
August 23, 2013 |
PCT NO: |
PCT/JP2013/072539 |
371 Date: |
February 19, 2015 |
Current U.S.
Class: |
310/71 |
Current CPC
Class: |
H02K 3/522 20130101;
H02K 23/30 20130101; H02K 3/527 20130101; H02K 3/28 20130101; H02K
13/04 20130101 |
International
Class: |
H02K 3/28 20060101
H02K003/28; H02K 13/04 20060101 H02K013/04 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 30, 2012 |
JP |
2012-189993 |
Dec 18, 2012 |
JP |
2012-276265 |
Claims
1. An electric motor comprising: a yoke having a plurality of
magnetic poles; a rotation shaft rotatably installed inside the
yoke; an armature core having a plurality of teeth attached to the
rotation shaft and radially extending in a radial direction, and a
plurality of slots formed between the teeth; a coil wound on each
of the teeth through an concentrated winding method; a commutator
installed at the rotation shaft adjacent to the armature core and
having a plurality of segments disposed in a circumferential
direction; and three brushes including a low speed brush and a high
speed brush configured to supply power to the coil via the
segments, and a common brush used in common with the low speed
brush and the high speed brush, wherein the number of magnetic
poles is set to 4, the number of slots is set to 6, and the number
of segments is set to 18, the coil wound on each of the teeth
comprises one forward wound coil formed to be wound forward, and
two reverse wound coils formed to be wound in reverse, when the
teeth are allocated in the circumferential direction in sequence of
a U phase, a V phase and a W phase, the forward wound coil wound on
each of the phases is provided as the coil of the U phase, the V
phase and the W phase, and the reverse wound coil wound on each of
the phases is provided as the coil of a -U phase, a -V phase and a
-W phase, the coils are electrically connected between the
neighboring segments in the order of the U phase, the -W phase, the
-W phase, the V phase, the -U phase, the -U phase, the W phase, the
-V phase and the -V phase, and the coil drawn between the armature
core and the commutator is drawn around the rotation shaft in the
same direction.
2. An electric motor comprising: a yoke having a plurality of
magnetic poles; a rotation shaft rotatably installed inside the
yoke; an armature core having a plurality of teeth attached to the
rotation shaft and radially extending in a radial direction, and a
plurality of slots formed between the teeth; a coil wound on each
of the teeth through an concentrated winding method; a commutator
installed at the rotation shaft adjacent to the armature core and
having a plurality of segments disposed in a circumferential
direction; and two brushes configured to supply power to the coil
via the segments, wherein the number of magnetic poles is set to 4,
the number of slots is set to 6, and the number of segments is set
to 18, the coil wound on each of the teeth comprises one forward
wound coil formed to be wound forward, and two reverse wound coils
formed to be wound in reverse, when the teeth are allocated in the
circumferential direction in sequence of a U phase, a V phase and a
W phase, the forward wound coil wound on each of the phases is
provided as the coil of the U phase, the V phase and the W phase,
and the reverse wound coil wound on each of the phases is provided
as the coil of a -U phase, a -V phase and a -W phase, the coils are
electrically connected between the neighboring segments in the
order of the U phase, the -W phase, the -W phase, the V phase, the
-U phase, the -U phase, the W phase, the -V phase and the -V phase,
and the coil drawn between the armature core and the commutator is
drawn around the rotation shaft in the same direction.
3. The electric motor according to claim 1 or 2, wherein, in the
segments, the segments having the same electric potential are
connected to each other by a connecting wire, when the coils of the
U phase, the -W phase, the -W phase, the V phase, the -U phase, the
-U phase, the W phase, the -V phase and the -V phase are formed,
the connecting wire is formed in series along with the coils of the
U phase, the -W phase, the -W phase, the V phase, the -U phase, the
-U phase, the W phase, the -V phase and the -V phase, when the
connecting wire is formed, the coil is drawn in the same direction
as when it is drawn between the armature core and the commutator,
and the coil is wound around a riser formed at the segment by an a
turn to connect the segment and the coil.
4. The electric motor according to claim 1 or 2, further comprising
an insulator configured to cover at least peripheries of the teeth
and having an insulation property, wherein the coil is formed by
winding a wire on the teeth from above the insulator, a partition
section configured to determine a place at which at least one of a
plurality of the coils are disposed is installed at the insulator,
and at least two accommodating portions configured to accommodate
the coil are formed on the insulator by the partition section.
5. The electric motor according to claim 4, wherein the partition
section is installed at least at one end in an axial direction of
the insulator.
6. The electric motor according to claim 4 or 5, wherein the
partition section is installed throughout the entire circumference
of the insulator.
7. The electric motor according to any one of claims 4 to 6,
wherein the partition section is installed such that capacities of
the accommodating portions are substantially uniformized.
8. The electric motor according to any one of claims 4 to 7,
wherein protrusion heights of the partition sections are different
from each other.
9. The electric motor according to claim 8, wherein the protrusion
heights of the partition sections are set to be lower as the
partition sections are disposed more inside in the radial
direction.
10. The electric motor according to any one of claims 4 to 9,
wherein the plurality of the coils are accommodated in the
accommodating portions in sequence from the accommodating portion
disposed inside in the radial direction to the accommodating
portion disposed outside in the radial direction.
Description
TECHNICAL FIELD
[0001] The present invention relates to, for example, an electric
motor mounted in a vehicle.
[0002] Priority is claimed on Japanese Patent Application No.
2012-189993, filed Aug. 30, 2012, and Japanese Patent Application
No. 2012-276265, filed Dec. 18, 2012, the contents of which are
incorporated herein by reference.
BACKGROUND ART
[0003] For example, as a wiper motor for an automobile, a 3-brush
type motor capable of changing a rotation speed is used. In such a
motor, an armature on which an armature coil is wound is rotatably
disposed inside a cylindrical yoke including a plurality of
magnetic poles formed at an inner circumferential surface thereof.
The armature has the armature core fitted and fixed onto a rotation
shaft, and a slot elongated in an axial direction is formed in the
armature core. In the slot, a wire is wound through a distributed
winding method at predetermined intervals to form a plurality of
coils. Each of the coils is electrically connected to a segment of
a commutator attached to a rotation shaft.
[0004] Each of the segments can come in contact with the brushes.
The brushes are configured of three brushes, i.e., a low speed
brush, a high speed brush, and a common brush commonly used for
these brushes. The high speed brush is disposed to be angularly
advanced more than the low speed brush. Then, power is supplied by
the common brush and the low speed brush during normal operation,
and supplied by the common brush and the high speed brush during
high speed operation. According to the above-mentioned
configuration, the 3-brush type motor can set a difference in the
numbers of effective conductors between during normal operation and
high speed operation. That is, in high speed operation, the motor
is more angularly advanced than in normal operation, and is
operated at a higher revolution speed than in normal operation.
[0005] Here, a motor such as a wiper motor or the like mounted in a
vehicle normally requires miniaturization due to requirements of
improvement of vehicle mountability or the like. For this reason,
for example, a motor in which the number of slots of the armature
core is set to 16 and the number of magnetic poles is set to 4 is
disclosed. In the motor, a coil is wound to straddle over four
teeth according to the number of magnetic poles through a
distributed winding method. Then, the coil is connected to a
commutator having sixteen segments in which the same electric
potentials are short-circuited (for example, see Patent Literature
1).
CITATION LIST
Patent Literature
[0006] [Patent Literature 1] Japanese Unexamined Patent
Application, First Publication No. 2010-226847
SUMMARY OF INVENTION
Technical Problem
[0007] Here, in order to obtain a large output, in many cases, the
motor of the related art mentioned above is connected to a speed
reducer (a speed reduction unit) when used. Here, an increase in a
speed reduction ratio of the speed reducer is considered as a means
for miniaturizing the motor. As the speed reduction ratio is
increased, the output of the motor itself can be suppressed, and as
a result, the motor can be reduced in size.
[0008] Here, while the number of revolutions of the motor should be
increased to an extent of the increase in speed reduction ratio,
when the number of slots is large, an order determined by the least
common multiple between the number of magnetic poles and the number
of slots is increased.
[0009] For this reason, noise from the motor reaches a high
frequency, and the noise may become dissonant.
[0010] In addition, since the shape of the armature core is
complicated as the number of slots is increased, productivity of
the armature may deteriorate.
[0011] Further, since the number of segments per pole pair is
reduced, the voltage between the segments is increased, and
rectification deteriorates.
[0012] Then, since the coil is wound on the teeth through the
distributed winding method, overlapping of coil ends increases, a
wire rod cost of the coil increases, motor performance decreases,
and the electric motor increases in size.
[0013] Here, in consideration of the above-mentioned circumstances,
the present invention provides an electric motor capable of
preventing generation of high frequency noise, increasing
productivity of an armature, and further improving rectification.
In addition, the present invention also provides an electric motor
capable of improving motor performance while reducing production
cost, and capable of being miniaturized.
Solution to Problem
[0014] According to a first aspect of the present invention, an
electric motor includes: a yoke having a plurality of magnetic
poles; a rotation shaft rotatably installed inside the yoke; an
armature core having a plurality of teeth attached to the rotation
shaft and radially extending in a radial direction, and a plurality
of slots formed between the teeth; a coil wound on each of the
teeth through an concentrated winding method; a commutator
installed at the rotation shaft adjacent to the armature core and
having a plurality of segments disposed in a circumferential
direction; and three brushes including a low speed brush and a high
speed brush configured to supply power to the coil via the
segments, and a common brush used in common with the low speed
brush and the high speed brush, wherein the number of magnetic
poles is set to 4, the number of slots is set to 6, and the number
of segments is set to 18, the coil wound on each of the teeth
comprises one forward wound coil formed to be wound forward, and
two reverse wound coils formed to be wound in reverse, when the
teeth are allocated in the circumferential direction in sequence of
a U phase, a V phase and a W phase, the forward wound coil wound on
each of the phases is provided as the coil of the U phase, the V
phase and the W phase, and the reverse wound coil wound on each of
the phases is provided as the coil of a -U phase, a -V phase and a
-W phase, the coils are electrically connected between the
neighboring segments in the order of the U phase, the -W phase, the
-W phase, the V phase, the -U phase, the -U phase, the W phase, the
-V phase and the -V phase, and the coil drawn between the armature
core and the commutator is drawn around the rotation shaft in the
same direction.
[0015] In addition, according to a second aspect of the present
invention, an electric motor includes: a yoke having a plurality of
magnetic poles; a rotation shaft rotatably installed inside the
yoke; an armature core having a plurality of teeth attached to the
rotation shaft and radially extending in a radial direction, and a
plurality of slots formed between the teeth; a coil wound on each
of the teeth through an concentrated winding method; a commutator
installed at the rotation shaft adjacent to the armature core and
having a plurality of segments disposed in a circumferential
direction; and two brushes configured to supply power to the coil
via the segments, wherein the number of magnetic poles is set to 4,
the number of slots is set to 6, and the number of segments is set
to 18, the coil wound on each of the teeth comprises one forward
wound coil formed to be wound forward, and two reverse wound coils
formed to be wound in reverse, when the teeth are allocated in the
circumferential direction in sequence of a U phase, a V phase and a
W phase, the forward wound coil wound on each of the phases is
provided as the coil of the U phase, the V phase and the W phase,
and the reverse wound coil wound on each of the phases is provided
as the coil of a -U phase, a -V phase and a -W phase, the coils are
electrically connected between the neighboring segments in the
order of the U phase, the -W phase, the -W phase, the V phase, the
-U phase, the -U phase, the W phase, the -V phase and the -V phase,
and the coil drawn between the armature core and the commutator is
drawn around the rotation shaft in the same direction.
[0016] According to the above-mentioned configuration, since the
number of slots can be reduced without motor performance
deteriorating, an order of the motor can be reduced. For this
reason, high frequency noise can be prevented upon high speed
rotation of the motor.
[0017] In addition, as the number of slots is reduced, the shape of
the armature core can be simplified and productivity of the
armature can be increased by the number of the slots reduced.
Further, the size of each of the slots can be set to increase as
the number of slots is reduced. For this reason, the number of
times that the coil is wound on the teeth can be set to be high. As
a result, the armature core can be reduced in size and weight.
[0018] Then, as the number of segments is set to three times or
more the number of slots, the number of segments per pole pair can
be increased. For this reason, a voltage between the segments can
be reduced, and rectification can be improved. In addition, since
the number of effective conductors of the coil per segment is
reduced, speed variation by the high speed brush becomes easy.
[0019] In addition, since the coil is wound on the teeth through
the concentrated winding method, a space factor of the coil can be
improved and overlapping of coil ends can be reduced in comparison
with the case in which the coil is wound through the distributed
winding method. For this reason, a wire rod cost of the coil can be
reduced, and an inexpensive electric motor can be provided.
Further, the armature core can be reduced in size and axial length
while having the same motor performance.
[0020] In addition, since the coil drawn between the armature core
and the commutator is drawn around the rotation shaft in the same
direction, an operation direction of the winding apparatus for
drawing the coil can become constant. For this reason, a load to
the winding apparatus can be reduced, workability of winding the
coil can be improved, irregularity of tension applied to the coil
is prevented, and further, the space factor can be improved.
Accordingly, the motor performance can be improved while reducing
the production cost.
[0021] The electric motor according to the present invention, in
the segments, the segments having the same electric potential are
connected to each other by a connecting wire, when the coils of the
U phase, the -W phase, the -W phase, the V phase, the -U phase, the
-U phase, the W phase, the -V phase and the -V phase are formed,
the connecting wire is formed in series along with the coils of the
U phase, the -W phase, the -W phase, the V phase, the -U phase, the
-U phase, the W phase, the -V phase and the -V phase, when the
connecting wire is formed, the coil is drawn in the same direction
as when it is drawn between the armature core and the commutator,
and the coil is wound around a riser formed at the segment by an a
turn to connect the segment and the coil.
[0022] According to the above-mentioned configuration, a connection
error between the segment and the coil can be securely prevented.
In addition, since stretching of the coil under a head of the
commutator can be securely suppressed, contact between the coils
wound around the neighboring risers can be suppressed. For this
reason, generation of heat can be suppressed, and an operation
error of the electric motor caused by exfoliation of a coating of
the coil and the contact between the coils wound around the
neighboring risers can be prevented.
Advantageous Effects of Invention
[0023] According to the above-mentioned electric motor, since the
number of slots can be reduced without motor performance
deteriorating, an order of the motor can be reduced. For this
reason, generation of high frequency noise during the high speed
rotation of the motor can be prevented.
[0024] In addition, as the number of slots is reduced, the shape of
the armature core can be simplified by the number of the slots
reduced, and productivity of the armature can be increased.
Further, as the number of slots is reduced, the size of each slot
can be set to a large size. For this reason, the number of turns of
the coil on each of the teeth can be set to a large value. As a
result, the armature core can be reduced in size and weight.
[0025] Then, as the number of segments is set to three times or
more the number of slots, the number of segments per pole pair can
be increased. For this reason, the voltage between the segments can
be reduced, and the rectification can be improved. In addition,
since the number of effective conductors of the coil per segment is
reduced, it is possible to easily deal with speed variation by the
high speed brush.
[0026] In addition, since the coil is wound on the teeth through
the concentrated winding method, a space factor of the coil can be
improved and overlapping of the coil end can be reduced in
comparison with the case in which the coil is wound through the
distributed winding method. For this reason, a wire rod cost of the
coil can be reduced, and an inexpensive electric motor can be
provided. Further, the armature core can be reduced in size and
axial length while having the same motor performance.
[0027] In addition, since the coil is drawn between the armature
core and the commutator and drawn around the rotation shaft in the
same direction, an operation direction of the winding apparatus for
drawing the coil can become constant. For this reason, a load to
the winding apparatus can be reduced, workability of winding the
coil can be improved, irregularity of tension applied to the coil
is prevented, and further, the space factor can be improved.
Accordingly, motor performance can be improved while reducing a
production cost.
BRIEF DESCRIPTION OF DRAWINGS
[0028] FIG. 1 is a longitudinal cross-sectional view of a reduction
motor according to an embodiment of the present invention.
[0029] FIG. 2 is a plan view of an electric motor according to the
embodiment of the present invention when seen in an axial
direction.
[0030] FIG. 3 is a plan view of a brush-receiving portion according
to the embodiment of the present invention.
[0031] FIG. 4 is a development view of an armature according to a
first embodiment of the present invention.
[0032] FIG. 5 is a view for describing a method of winding a wire
around a riser of each segment according to the first embodiment of
the present invention.
[0033] FIG. 6 is an enlarged perspective view of a riser portion of
a commutator according to the first embodiment of the present
invention, showing a state in which a wire is wound on the riser by
an a turn.
[0034] FIG. 7 is an enlarged perspective view of the riser portion
of the commutator according to the first embodiment of the present
invention, showing a state in which the wire is not wound on the
riser by the a turn.
[0035] FIG. 8 is a development view of an armature according to a
second embodiment of the present invention.
[0036] FIG. 9 is a plan view of a brush-receiving portion according
to a third embodiment of the present invention.
[0037] FIG. 10 is a development view of an armature according to
the third embodiment of the present invention.
[0038] FIG. 11 is a longitudinal cross-sectional view of a
reduction motor according to a fourth embodiment of the present
invention.
[0039] FIG. 12 is a perspective view of an armature according to
the fourth embodiment of the present invention.
[0040] FIG. 13 is a plan view of an armature core according to the
fourth embodiment of the present invention.
[0041] FIG. 14 is a development view of the armature according to
the fourth embodiment of the present invention.
[0042] FIG. 15 is a perspective view showing a state in which an
insulator is mounted on the armature core according to the fourth
embodiment of the present invention.
[0043] FIG. 16 is an enlarged perspective view of the insulator
mounted on the armature core according to the fourth embodiment of
the present invention when seen from the commutator side.
[0044] FIG. 17 is a perspective view of the insulator according to
the fourth embodiment of the present invention.
[0045] FIG. 18 is a view for describing relations between each
partition wall, a winding collapse prevention plate and a winding
collapse prevention convex portion according to the fourth
embodiment of the present invention.
[0046] FIG. 19 is a perspective view showing a state in which an
insulator is mounted on an armature core according to a first
modified example of the fourth embodiment of the present
invention.
[0047] FIG. 20 is a perspective view showing a state in which an
insulator is mounted on an armature core according to a second
modified example of the fourth embodiment of the present
invention.
[0048] FIG. 21 is a perspective view showing a state in which an
insulator is mounted on an armature core according to a third
modified example of the fourth embodiment of the present
invention.
[0049] FIG. 22 is a development view of an armature according to a
fifth embodiment of the present invention.
[0050] FIG. 23 is a perspective view showing a state in which an
insulator is mounted on the armature core according to the fifth
embodiment of the present invention.
[0051] FIG. 24 is a view for describing relations between a
partition wall, a winding collapse prevention plate and a winding
collapse prevention convex portion according to the fifth
embodiment of the present invention.
[0052] FIG. 25 is a perspective view showing a state in which an
insulator is mounted on an armature core according to a first
modified example of the fifth embodiment of the present
invention.
[0053] FIG. 26 is a perspective view showing a state in which an
insulator is mounted on an armature core according to a second
modified example of the fifth embodiment of the present
invention.
[0054] FIG. 27 is a perspective view showing a state in which an
insulator is mounted on an armature core according to a third
modified example of the fifth embodiment of the present
invention.
DESCRIPTION OF EMBODIMENTS
First Embodiment
(Reduction Motor)
[0055] Next, a first embodiment of the present invention will be
described based on FIGS. 1 to 6.
[0056] FIG. 1 is a longitudinal cross-sectional view of a reduction
motor to which an electric motor according to an embodiment of the
present invention is applied, and FIG. 2 is a plan view of the
electric motor when seen in an axial direction.
[0057] As shown in FIGS. 1 and 2, a reduction motor 1 includes an
electric motor 2, and a speed reduction mechanism 4 connected to a
rotation shaft 3 of the electric motor 2. The electric motor 2 has
a bottomed cylindrical yoke 5, and an armature 6 rotatably
installed in the yoke 5.
[0058] A cylindrical portion 53 of the yoke 5 is formed in a
substantially cylindrical shape, and four segment-type permanent
magnets 7 are disposed at an inner circumferential surface of the
cylindrical portion 53.
[0059] A bearing housing 19 protruding outward in an axial
direction is formed at a center in a radial direction of a bottom
wall (an end portion) 51 of the yoke 5, and a sliding bearing 18
configured to rotatably and axially support one end of the rotation
shaft 3 is installed at the bottom wall 51. The sliding bearing 18
has a centering function of the rotation shaft 3.
[0060] An outer flange portion 52 is formed at an opening portion
53a of the cylindrical portion 53. A bolt hole (not shown) is
formed at the outer flange portion 52. The yoke 5 is fastened and
fixed to the speed reduction mechanism 4 by inserting a bolt (not
shown) through the bolt hole and by screwing the bolt into a bolt
hole (not shown) formed in a gear housing 23 (to be described
below) of the speed reduction mechanism 4.
[0061] The armature 6 includes an armature core 8 fixedly fitted
onto the rotation shaft 3, an armature coil 9 wound on the armature
core 8, and a commutator 10 disposed at the other end side of the
rotation shaft 3. The armature core 8 is formed by stacking plate
members formed of a magnetic material and punched through pressing
in the axial direction (a stacked core) or pressure-forming a soft
magnetic powder (a pressed powder core), and has a substantially
columnar core main body 11.
[0062] A through-hole 11a through which the rotation shaft 3 is
press-fitted is formed in substantially the center in the radial
direction of the core main body 11. In addition, six teeth 12 each
having substantially a T shape when seen from a plan view in the
axial direction are formed radially at an outer circumferential
portion of the core main body 11. As the teeth 12 are radially
installed at the outer circumferential portion of the core main
body 11, six slots 13 having dovetail grooves are formed between
the neighboring teeth 12.
[0063] The armature coil 9 is wound on the armature core 8 via the
slots 13.
[0064] Here, six holes 11b having circular cross sections and
penetrating in the axial direction are formed in the core main body
11 in the circumferential direction at positions corresponding to
roots of the teeth 12. More specifically, the holes 11b are formed
between the through-hole 11a of the core main body 11 and the teeth
12 at positions slightly closer to the through-hole 11a from a
substantially center between the through-hole 11a and the roots of
the teeth 12 in the radial direction. The holes 11b are configured
to promote convection of air in the electric motor 2 and suppress
an increase in temperature of the electric motor 2.
[0065] The commutator 10 is fixedly fitted onto the other end side
of the rotation shaft 3 closer than the armature core 8. Eighteen
segments 15 formed of a conductive material are attached to an
outer circumferential surface of the commutator 10. The segments 15
are formed of plate-shaped metal pieces elongated in the axial
direction, and are insulated from each other and fixed in parallel
at equal intervals in the circumferential direction.
[0066] In this way, the electric motor 2 is a four-pole six-slot
eighteen-segment electric motor in which the number of permanent
magnets 7 is set to 4 (the number of magnetic poles is 4), the
number of slots 13 is set to 6, and the number of segments 15 is
set to 18.
[0067] In addition, a riser 16 bent in a shape that returns to an
outer diameter side is integrally formed with an end portion of the
armature core 8 side of each of the segments 15. A terminal portion
of the armature coil 9 is wound around and fixed to the riser 16
through fusing or the like. Accordingly, the segments 15 and the
armature coils 9 corresponding thereto are electrically connected
to each other.
[0068] In addition, a connecting wire 17 (see FIG. 4) is wound
around the risers 16 corresponding to the segments 15 having the
same electric potential, and the connecting wire 17 is fixed to the
riser 16 through fusing. The connecting wire 17 short-circuits the
segments 15 having the same electric potential, and is drawn
between the commutator 10 and the armature core 8 (to be described
in detail below).
[0069] The commutator 10 having the above-mentioned configuration
faces the gear housing 23 of the speed reduction mechanism 4. The
gear housing 23 is configured of a housing main body 42 formed in
substantially a box shape having an opening portion 42a at one
surface thereof through an aluminum die-casting method and
configured to receive a gear group 41 of the speed reduction
mechanism 4, and a bottom plate 43 formed of a resin and configured
to close the opening portion 42a of the housing main body 42. A
brush-receiving portion 22 is integrally formed with the housing
main body 42 near the electric motor 2, and the commutator 10 of
the electric motor 2 faces the brush-receiving portion 22.
(Brush-Receiving Portion)
[0070] FIG. 3 is a plan view of the brush-receiving portion 22.
[0071] As shown in FIG. 3, the brush-receiving portion 22 is formed
in a concave shape at the gear housing 23 near the electric motor
2. A circumferential wall 30 of the brush-receiving portion 22 is
formed in a substantially oval shape, and configured of a planar
wall 30a and an arc wall 30b.
[0072] A cover 33 is formed inside the brush-receiving portion 22
formed in a cylindrical shape having a substantially oval cross
section to correspond thereto. The cover 33 also has a planar wall
33a and an arc wall 33b. Further, a holder stay 34 formed to
correspond to the cover 33 is installed inside the cover 33. The
holder stay 34 is fastened and fixed to a sidewall 42b of the
housing main body 42 by a bolt 35.
[0073] Three brush holders 36 are installed at the holder stay 34
in the circumferential direction. Brushes 21 are installed in the
brush holders 36 to protrude from and withdraw into the brush
holders 36 in a state that each of the brushes 21 are biased via
each of springs S. Front end portions of the brushes 21 are biased
by the springs S and thus come in sliding contact with the segments
15 of the commutator 10. In addition, the brushes 21 are
electrically connected to an external power supply (not shown), for
example, a battery mounted in an automobile. Then, power can be
supplied from the external power supply (not shown) to the
commutator 10.
[0074] The brushes 21 are configured of a low speed brush 21a and a
high speed brush 21b connected to a positive electrode side, and a
common brush 21c used in common for the low speed brush 21a and the
high speed brush 21b and connected to a negative electrode side.
The low speed brush 21a and the common brush 21c are disposed at an
electrical angle of 180.degree., i.e., at a mechanical angle of a
90.degree. interval in the circumferential direction. The high
speed brush 21b is disposed to be spaced an angle .alpha. from the
low speed brush 21a in the circumferential direction. Further, in
the embodiment, while the common brush 21c is described as being
disposed at the negative electrode side, and the low speed brush
21a and the high speed brush 21b are described as being disposed at
the positive electrode side, the positive electrode side and the
negative electrode side may be reversed.
[0075] Here, since the segments 15 having the same electric
potential of the commutator 10, i.e., the segments 15 opposite to
each other with respect to the rotation shaft 3, are
short-circuited by the connecting wire 17, power can also be
supplied to the segments not in contact with the brush 21.
Accordingly, the high speed brush 21b is present at a position
angularly advanced from the low speed brush 21a by an angle
.theta..
(Wire Connecting Structure of Connecting Wire, and Winding
Structure of Armature Coil)
[0076] Here, based on FIG. 4, a wire connecting structure of the
connecting wire 17 and a winding structure of the armature coil 9
will be described in detail.
[0077] FIG. 4 is a development view of the armature 6, and a gap
between the neighboring teeth 12 corresponds to the slot 13.
Further, in description of FIG. 4, reference numerals are
designated to the segments 15, the teeth 12 and the armature coils
9 wound thereon.
[0078] As shown in FIG. 4, the teeth 12 having a U phase, a V phase
and a W phase are allocated in the circumferential direction in
this order. That is, the first and fourth teeth 12 have the U
phase, the second and fifth teeth 12 have the V phase, and the
third and sixth teeth 12 have the W phase. In addition, the
segments 15 having the same electric potential are short-circuited
to each other by the connecting wire 17. Here, a position
corresponding to the number designated to the segment 15
corresponding to No. 1 is a position corresponding to the first
tooth 12.
[0079] Then, the armature coil 9 and the connecting wire 17 wound
on the teeth 12 are formed by winding a wire 14 on the riser 16 of
the armature core 8 or the commutator 10 through a double flyer
method. Further, the double flyer method is a method of
simultaneously winding the wire 14 about the rotation shaft 3 at
two positions having a point-symmetrical relationship. Hereinafter,
the method will be described in detail.
[0080] Here, there are two winding starting ends 81 of the wire 14,
which are wound around the riser 16 of the first segment 15 and the
riser 16 of the tenth segment 15 having the same electric
potential. Then, a drawing direction of the wire 14 drawn between
the armature core 8 and the commutator 10 is set to be same
direction as the wire 14 drawn to form the connecting wire 17
around the rotation shaft 3.
[0081] Further, in the following description, a direction of
sequentially allocating the U phase, the V phase and the W phase to
the teeth 12, i.e., right in FIG. 4, is simply referred to as
"right".
[0082] In addition, since a drawing sequence of the wire 14
initially wound from the first segment 15 and the wire 14 initially
wound from the tenth segment 15 is point-symmetrical about the
rotation shaft 3, in the following description, only the wire 14
initially wound from the tenth segment 15 will be described.
[0083] The wire 14 having the winding starting end 81 wound around
the riser 16 of the tenth segment 15 is drawn to the right while
being wound around the rotation shaft 3, and then wound around the
first segment 15 having the same electric potential as the tenth
segment 15. Then, when the wire 14 is drawn from the commutator 10
toward the armature core 8, the wire 14 is drawn to the right while
being wound around the rotation shaft 3 and is pulled into the slot
13 between the first and sixth teeth 12. Next, when the wire 14 is
wound on the teeth 12 N (N is a natural number of 1 or more) times,
the wire 14 is wound forward on the first tooth 12 N/3 times to
form a U phase coil 91a.
[0084] Next, the wire 14 is pulled out of the slot 13 between the
first and second teeth 12, and the wire 14 is drawn to the right
while being wound around the rotation shaft 3 and is wound around
the riser 16 of the second segment 15 adjacent to the first segment
15. Next, the wire 14 is drawn to the right while being wound
around the rotation shaft 3 and is wound around the riser 16 of the
eleventh segment 15 having the same electric potential as the
second segment 15. Once more, when the wire 14 is drawn from the
commutator 10 toward the armature core 8, the wire 14 is drawn to
the right while being wound around the rotation shaft 3 and is
pulled into the slot 13 between the third and fourth teeth 12.
Then, the wire 14 is wound in reverse on the third tooth 12 N/3
times to form a "-W phase" coil 91b.
[0085] Next, the wire 14 is pulled out of the slot 13 between the
second and third teeth 12, and the wire 14 is drawn to the right
while being wound around the rotation shaft 3 and is wound around
the riser 16 of the third segment 15 adjacent to the second segment
15. Next, the wire 14 is drawn to the right while being wound
around the rotation shaft 3 and is wound around the riser 16 of the
twelfth segment 15 having the same electric potential as the third
segment 15. Once again, when the wire 14 is drawn from the
commutator 10 toward the armature core 8, the wire 14 is drawn to
the right while being wound around the rotation shaft 3 and is
pulled into the slot 13 between the third and fourth teeth 12.
Then, the wire 14 is wound in reverse on the third tooth 12 N/3
times to form a "-W phase" coil 92b.
[0086] Next, the wire 14 is pulled out of the slot 13 between the
second and third teeth 12, and the wire 14 is drawn to the right
while being wound around the rotation shaft 3 and is wound around
the riser 16 of the fourth segment 15 adjacent to the third segment
15. Next, the wire 14 is drawn to the right while being wound
around the rotation shaft 3, and is wound around the riser 16 of
the thirteenth segment 15 having the same electric potential as the
fourth segment 15. Once more, when the wire 14 is drawn from the
commutator 10 toward the armature core 8, the wire 14 is drawn to
the right while being wound around the rotation shaft 3 and is
pulled into the slot 13 between the fourth and fifth teeth 12.
Then, the wire 14 is wound forward on the fifth tooth 12 N/3 times
to form a V phase coil 91c.
[0087] Next, the wire 14 is pulled out of the slot 13 between the
fifth and sixth teeth 12, and the wire 14 is drawn to the right
while being wound around the rotation shaft 3 and is wound around
the riser 16 of the fourteenth segment 15 adjacent to the
thirteenth segment 15. Next, the wire 14 is drawn to the right
while being wound around the rotation shaft 3, and the wire 14 is
wound around the riser 16 of the fifth segment 15 having the same
electric potential as the fourteenth segment 15. Once more, when
the wire 14 is drawn from the commutator 10 toward the armature
core 8, the wire 14 is drawn to the right while being wound around
the rotation shaft 3 and is pulled into the slot 13 between the
first and second teeth 12. Then, the wire 14 is wound in reverse on
the first tooth 12 N/3 times to form a "-U phase" coil 92a.
[0088] Next, the wire 14 is pulled out of the slot 13 between the
first and sixth teeth 12, and the wire 14 is drawn to the right
while being wound around the rotation shaft 3 and is wound around
the riser 16 of the fifteenth segment 15 adjacent to the fourteenth
segment 15. Next, the wire 14 is drawn to the right while being
wound around the rotation shaft 3, and the wire 14 is wound around
the riser 16 of the sixth segment 15 having the same electric
potential as the fifteenth segment 15. Once more, when the wire 14
is drawn from the commutator 10 toward the armature core 8, the
wire 14 is drawn to the right while being wound around the rotation
shaft 3 and is pulled into the slot 13 between the first and second
teeth 12. Then, the wire 14 is wound in reverse on the first tooth
12 N/3 times to form a "-U phase" coil 93a.
[0089] Next, the wire 14 is pulled out of the slot 13 between the
first and sixth teeth 12, and the wire 14 is drawn to the right
while being wound around the rotation shaft 3 and is wound around
the riser 16 of the sixteenth segment 15 adjacent to the fifteenth
segment 15. Next, the wire 14 is drawn to the right while being
wound around the rotation shaft 3, and the wire 14 is wound around
the riser 16 of the seventh segment 15 having the same electric
potential as the sixteenth segment 15. Once more, when the wire 14
is drawn from the commutator 10 toward the armature core 8, the
wire 14 is drawn to the right while being wound around the rotation
shaft 3 and is pulled into the slot 13 between the second and third
teeth 12. Then, the wire is wound forward on the third tooth 12
direction N/3 times to form a W phase coil 93b.
[0090] Next, the wire 14 is pulled out of the slot 13 between the
third and fourth teeth 12, and the wire 14 is drawn to the right
while being wound around the rotation shaft 3 and is wound around
the riser 16 of the eighth segment 15 adjacent to the seventh
segment 15. Next, the wire 14 is drawn to the right while being
wound around the rotation shaft 3, and the wire 14 is wound around
the riser 16 of the seventeenth segment 15 having the same electric
potential as the eighth segment 15. Once more, when the wire 14 is
drawn from the commutator 10 toward the armature core 8, the wire
14 is drawn to the right while being wound around the rotation
shaft 3 and is pulled into the slot 13 between the fifth and sixth
teeth 12. Then, the wire 14 is wound in reverse on the fifth tooth
12 N/3 times to form a "-V phase" coil 92c.
[0091] Next, the wire 14 is pulled out of the slot 13 between the
fourth and fifth teeth 12, and the wire 14 is drawn to the right
while being wound around the rotation shaft 3 and is wound around
the riser 16 of the ninth segment 15 adjacent to the eighth segment
15. Next, the wire 14 is drawn to the right while being wound
around the rotation shaft 3, and the wire 14 is wound around the
riser 16 of the eighteenth segment 15 having the same electric
potential as the ninth segment 15. Once more, when the wire 14 is
drawn from the commutator 10 toward the armature core 8, the wire
14 is drawn to the right while being wound around the rotation
shaft 3 and is pulled into the slot 13 between the fifth and sixth
teeth 12. Then, the wire is wound in reverse on the fifth tooth 12
N/3 times to form a "-V phase" coil 93c.
[0092] After that, the wire 14 is pulled out of the slot 13 between
the fourth and fifth teeth 12, the wire 14 is drawn to the right
while being wound around the rotation shaft 3 and is wound around
the riser 16 of the tenth segment 15 adjacent to the ninth segment
15, and a winding terminating end 82 of the wire 14 is connected to
the tenth segment 15.
[0093] Accordingly, the armature coil 9U1 of the U phase configured
of the U phase coil 91a, the "-U phase" coil 92a and the "-U phase"
coil 93a and wound N times is formed at the first tooth 12. In
addition, the armature coil 9W1 of the W phase configured of the
"-W phase" coil 91b, the "-W phase" coil 92b and the W phase coil
93b and wound N times is formed at the third tooth 12. Further, the
armature coil 9V1 of the V phase configured of the V phase coil
91c, the "-V phase" coil 92c and the "-V phase" coil 93c and wound
N times is formed at the fifth tooth 12.
[0094] The wire 14 having the winding starting end 81 wound around
the riser 16 of the first segment 15 is drawn along with the wire
14 having the winding starting end 81 wound around the riser 16 of
the above-mentioned tenth segment 15 and point-symmetrically about
the rotation shaft 3.
[0095] Then, the armature coil 9V2 of the V phase configured of a V
phase coil 91d, a "-V phase" coil 92d, and a "-V phase" coil 93d
and wound N times is formed at the second tooth 12. In addition,
the armature coil 9U2 of the U phase configured of a U phase coil
91e, a "-U phase" coil 92e and a "-U phase" coil 93e and wound N
times is formed at the fourth tooth 12. Further, the armature coil
9W2 of the W phase configured of a "-W phase" coil 91f, a "-W
phase" coil 92f and a W phase coil 93f and wound N times is formed
at the sixth tooth 12.
[0096] In this way, the armature coil 9 is configured of the
armature coils 9U1 and 9U2 of the U phase formed at the first and
fourth teeth 12, the armature coils 9V1 and 9V2 of the V phase
formed at the second and fifth teeth 12, and the armature coils 9W1
and 9W2 of the W phase formed at the third and sixth teeth 12, and
the number of parallel circuits thereof is four.
[0097] Then, the phase coils 91a to 93f are electrically and
sequentially connected between the neighboring segments 15 in
sequence of U, "-W," "-W," V, "-U," "-U," W, "-V" and "-V"
phases.
[0098] Here, as shown in FIG. 2, since the wire 14 is wound on the
teeth 12 through the concentrated winding method, there is no
crossover wire of the wire 14 that extends across neighboring teeth
12. That is, overlapping of a coil end 9a of the armature coil 9 at
an end portion in the axial direction of the armature core 8 is
reduced in comparison with the case in which the wire 14 is wound
through the distributed winding method. For this reason, the end
portion in the axial direction of the core main body 11 of the
armature core 8 is not covered by the wire 14 but the hole 11b
formed at the core main body 11 is exposed.
[0099] In addition, since the wire 14 between the armature core 8
and the riser 16 of the segment 15 is drawn to be wound around the
rotation shaft 3, thickening of the winding under a head of the
commutator 10 is suppressed.
[0100] Further, since a drawing direction of the wire 14 drawn
between the armature core 8 and the commutator 10 and the wire 14
drawn to form the connecting wire 17 is set to the entirely same
direction (right in FIG. 4) around the rotation shaft 3 the wire 14
is wound on the riser 16 of each of the segments 15 by an a
turn.
[0101] The .alpha. turn will be described in detail based on FIG.
5.
[0102] FIG. 5 is a view for describing a method of winding the wire
around the riser of each of the segments.
[0103] As shown in FIG. 5, since a drawing direction of the wire 14
drawn between the armature core 8 and the commutator 10 and the
wire 14 drawn to form the connecting wire 17 is set to the entirely
same direction (right in FIG. 4) around the rotation shaft 3, the
wire 14 wound around the riser 16 of each of the segments 15 is
normally wound around the riser 16 from the left, and pulled out to
the right. For this reason, as shown in a portion A of FIG. 5, the
wire 14 is wound on the riser 16 by the a turn.
(Speed Reduction Mechanism)
[0104] As shown in FIG. 1, in the gear housing 23 to which the
electric motor 2 is attached, the gear group 41 is received in the
housing main body 42. The gear group 41 is configured of a worm
shaft 25 connected to the rotation shaft 3 of the electric motor 2,
a pair of stepped gears 26 and 26 meshed with the worm shaft 25,
and a spur gear 27 meshed with the stepped gear 26.
[0105] The worm shaft 25 has one end connected to the rotation
shaft 3 and the other end rotatably and axially supported by the
housing main body 42. A connecting portion 24 of the worm shaft 25
and the rotation shaft 3, i.e., the other end of the rotation shaft
3, is rotatably supported by a roll bearing 32 installed at a
bottom wall 31 of the brush-receiving portion 22 formed at the
housing main body 42.
[0106] In addition, the worm shaft 25 has a first screw portion 25a
and a second screw portion 25b, which are reversely screwed to each
other. The first screw portion 25a and the second screw portion 25b
are formed as single-start thread or double-start thread. However,
the first screw portion 25a and the second screw portion 25b may be
formed as multi-start thread with three or more starts.
[0107] The pair of stepped gears 26 and 26 are disposed at both
sides with the worm shaft 25 sandwiched therebetween, and the pair
of stepped gears 26 and 26 are meshed with the first screw portion
25a and the second screw portion 25b.
[0108] The pair of stepped gears 26 have a worm wheel 28 meshed
with the worm shaft 25 and a small diameter gear 29 having a
smaller diameter than the worm wheel 28 is integrally formed
therewith. An idler shaft 61 is press-fitted into a center in the
radial direction of the stepped gear 26. The idler shaft 61
protrudes at an opposite side of the small diameter gear 29, and a
protruding end portion 61a is rotatably and axially supported by
the housing main body 42. A front end of the small diameter gear 29
at an end of the idler shaft 61 opposite to the end portion 61a is
rotatably and axially supported by the bottom plate 43.
[0109] In this way, both ends of the pair of stepped gears 26 are
axially supported by the housing main body 42 and the bottom plate
43. Then, the pair of stepped gears 26 and 26 rotate in the same
direction, and rotation of the worm shaft 25 is transmitted to the
spur gear 27. That is, a marshal mechanism is constituted by the
worm shaft 25 and the pair of stepped gears 26 and 26, and a thrust
force applied to the worm shaft 25 is offset by the pair of stepped
gears 26 and 26.
[0110] The spur gear 27 is meshed with the small diameter gear 29
of the stepped gear 26. A boss portion 65 protrudes from a center
in the radial direction of the spur gear 27 toward the bottom plate
43. The boss portion 65 is rotatably supported by the bottom plate
43. In addition, an output shaft 62 is press-fitted into the boss
portion 65. The output shaft 62 protrudes from a bottom wall (an
end portion) 42c of the housing main body 42. A boss portion 63
protrudes outward from the bottom wall 42c of the housing main body
42 at an area corresponding to the output shaft 62. A sliding
bearing 64 configured to rotatably and axially support the output
shaft 62 is installed at the boss portion 63.
[0111] A tapered portion 66 gradually tapered toward the front end
is formed at a portion of the output shaft 62 protruding from the
housing main body 42. A serration 67 is formed at the tapered
portion 66. Accordingly, for example, an external mechanism
configured to drive a wiper or the like can be connected to the
output shaft 62.
[0112] In addition, a connector 68 projects from the sidewall 42b
of the housing main body 42 in the axial direction of the rotation
shaft 3. The connector 68 is connected to a controller (not shown),
and supplies power of an external power supply (not shown) to the
electric motor 2.
[0113] A substrate 71 is disposed at an inner surface 43a of the
bottom plate 43 configured to close the opening portion 42a of the
housing main body 42. A terminal 72 configured to electrically
connect the connector 68 and the electric motor 2 is installed at
the substrate 71. In addition, contactors 73a and 73b are installed
at the substrate 71. The contactors 73a and 73b are sliding
contacts configured to detect a rotation position of the spur gear
27. Contact plates (not shown) are installed at areas with which
the contactors 73a and 73b of the spur gear 27 come in sliding
contact.
[0114] Then, the rotation position of the output shaft 62 can be
detected as the contact positions between the contactors 73a and
73b and the contact plates (not shown) are varied or come in and
out of contact with each other according to rotation of the spur
gear 27, i.e., the output shaft 62. A signal detected by the
contactors 73a and 73b is output to the controller (not shown) via
the terminal 72, and rotation control of the electric motor 2 is
performed.
(Action of Electric Motor)
[0115] Next, based on FIG. 4, an action of the electric motor 2
will be described.
[0116] For example, the case in which a voltage is applied between
the low speed brush 21a and the common brush 21c in a state shown
in FIG. 4 in which the low speed brush 21a is disposed between the
first and second segments 15 and the common brush 21c is disposed
at the sixth segment 15 will be described.
[0117] In this case, since the low speed brush 21a is disposed to
extend across the first and second segments 15 and 15, forward
wound coils 91a and 91e of the U phase are short-circuited.
[0118] Current flows in reverse (counterclockwise in FIG. 4)
through "-U phase" coils 92a and 92e wound on the first tooth 12
and the fourth tooth 12. On the other hand, current flows forward
(clockwise in FIG. 4) through "-U phase" coils 93a and 93e wound on
the first tooth 12 and the fourth tooth 12. In this way, since
currents flow in opposite directions through the "-U phase" coils
92a and 92e and the "-U phase" coils 93a and 93e wound on the first
tooth 12 and the fourth tooth 12 and are not short-circuited by the
brushes 21a and 21c, the magnetic fields are offset, and no torque
is generated on the permanent magnet 7.
[0119] On the other hand, current flows forward through the V phase
coils 91c and 91d, the "-V phase" coils 92c and 92d, and the "-V
phase" coils 93c and 93d wound on the second tooth 12 and the fifth
tooth 12.
[0120] Current flows in reverse through the "-W phase" coils 91b
and 91f, the "-W phase" coils 92b and 92f, and the W phase coils
93b and 93f wound on the third tooth 12 and the sixth tooth 12.
[0121] Then, magnetic fields are formed at the second, third, fifth
and sixth teeth 12. Since directions of the magnetic fields are
provided in sequence in the circumferential direction, a magnetic
attractive force or a repulsive force is applied in the same
direction at point-symmetrical positions about the rotation shaft 3
between the magnetic field formed at the teeth 12 and the permanent
magnet 7. Then, according to the force, the rotation shaft 3 is
rotated.
[0122] When the rotation shaft 3 starts to rotate, the segments 15
in contact with the brushes 21a and 21c are sequentially changed
and a direction of the current flowing through the coil is shifted,
i.e., rectification is performed. Accordingly, the rotation shaft 3
is continuously rotated.
[0123] On the other hand, when the voltage is applied between the
high speed brush 21b and the common brush 21c, since the high speed
brush 21b is at a position angularly advanced more than the low
speed brush 21a by the angle .theta. (see FIGS. 3 and 4), in
comparison with the case in which the voltage is applied between
the low speed brush 21a and the common brush 21c, the number of
effective conductors to which an electric current is applied is
reduced. For this reason, when the voltage is applied between the
high speed brush 21b and the common brush 21c, the electric motor 2
is angularly advanced and operated at a higher speed than when the
voltage is applied between the low speed brush 21a and the common
brush 21c.
(Effects)
[0124] Accordingly, according to the above-mentioned first
embodiment, the four permanent magnets 7 are installed at the yoke
5, the six slots 13 are formed in the armature core 8, the eighteen
segments 15 are installed at the commutator 10, and the order
determined by the least common multiple between the number of
magnetic poles and the number of slots can be set to 12. On the
other hand, in the electric motor of the related art, since the
number of magnetic poles is set to 4 and the number of slots is set
to 16, the order is 32. For this reason, since the order can be
reduced in comparison with the related art without deteriorating
the motor performance, generation of high frequency noise can be
prevented during the high speed rotation of the electric motor
2.
[0125] In addition, while the number of slots of the related art is
16, since the number of slots of the armature core 8 is 6, the
shape of the armature core 8 can be simplified and productivity of
the armature 6 can be increased to the extent to which the number
of slots is reduced.
[0126] Further, the size of each of the slots 13 can be set to be
larger according to the extent to which the number of slots is
reduced. For this reason, the number of windings of the wire 14 on
the teeth 12 can be set to be large, and as a result, the armature
core 8 can be reduced in size and weight.
[0127] Then, since the number of segments is set to three times the
number of slots, the number of segments per pole pair is increased
to be larger than that of the related art. For this reason, the
voltage between the segments 15 can be reduced, and rectification
can be improved in comparison with the related art. In addition,
since the number of effective conductors of the armature coil 9 per
segment 15 is reduced, speed can be easily varied using the high
speed brush 21b.
[0128] In addition, since the wire 14 is wound on the teeth 12
through the concentrated winding method, the crossover line of the
wire 14 that extends across the neighboring teeth 12 can be
removed. A wire rod cost of the armature coil 9 can be reduced to
that extent, and an inexpensive electric motor 2 can be
provided.
[0129] Further, since the wire 14 is wound on the teeth 12 through
the concentrated winding method, the space factor of the wire 14
can be improved in comparison with the case in which the wire 14 is
wound through the distributed winding method as described in the
related art, and overlapping of the coil end 9a can be reduced. For
this reason, since copper loss can be reduced, high efficiency of
the electric motor 2 can be achieved. Then, the armature core 8 can
be reduced in size and axial length while having the same motor
performance.
[0130] Then, the end portion in the axial direction of the core
main body 11 of the armature core 8 is not covered by the wire 14
because the crossover line of the wire 14 is removed. For this
reason, the hole 11b formed at the core main body 11 can be
securely exposed, and convection of the air in the electric motor 2
can be promoted. For this reason, an increase in temperature of the
electric motor 2 can be suppressed, and motor efficiency can be
improved.
[0131] In addition, since the wire 14 drawn between the armature
core 8 and the commutator 10 is drawn in the same direction (right
in FIG. 4) around the rotation shaft 3 as a whole, an operation
direction of the winding apparatus (not shown) for drawing the wire
14 can be constantly maintained. For this reason, a load to the
winding apparatus (not shown) can be reduced, workability of
winding the wire 14 can be improved, irregularity of tension
applied to the wire 14 is prevented, and further, a space factor
can be improved. Accordingly, motor performance of the electric
motor 2 can be improved while reducing a production cost.
[0132] Further, in addition to the wire 14 drawn between the
armature core 8 and the commutator 10, the drawing direction of the
wire 14 drawn to form the connecting wire 17 is also set to the
same direction (right in FIG. 4), and the wire 14 is wound on the
riser 16 of the segment 15 by the a turn. For this reason, a
connection error between the segment 15 and the wire 14 can be
securely prevented. In addition, since stretching of the wire 14
under the head of the commutator 10 can be securely suppressed,
contact between the wires 14 wound around the neighboring risers 16
can be suppressed, and generation of heat can be suppressed.
[0133] Suppression of generation of the connection error and heat
of the wire 14 will be described based on FIGS. 6 and 7.
[0134] FIG. 6 is an enlarged perspective view of a riser portion of
the commutator, showing a state in which the wire is wound on the
riser by the a turn. FIG. 7 is an enlarged perspective view of the
riser portion of the commutator, showing a state in which the wire
is not wound on the riser by the a turn.
[0135] As shown in FIG. 6, as the wire 14 is wound on each of the
risers 16 by the a turn, the wire 14 is wound around and encloses a
periphery of each of the risers 16. On the other hand, when the
wire 14 is not wound on the riser 16 by the a turn, in other words,
when the wire 14 is wound on the riser 16 in a U winding shape, the
wire 14 is merely hooked on the riser 16. For this reason, as the
wire 14 is wound on the risers 16 by the a turn, a connection error
of the segment 15 and the wire 14 can be securely prevented.
[0136] In addition, as shown in FIG. 6, as the wire 14 is wound on
the risers 16 by the a turn, the wire 14 crosses under the head of
the commutator 10, and stretching of the wire 14 under the head of
the commutator 10 is suppressed. On the other hand, when the wire
14 is not wound on the riser 16 by the a turn, the wire 14 does not
cross under the head of the commutator 10, and the wire 14 is
stretched. In this way, when the wire 14 is stretched under the
commutator 10, the wires 14 wound around the neighboring risers 16
come in contact with each other, and generation of the heat is
promoted. For this reason, as the wire 14 is wound on the risers 16
by the a turn, generation of the heat can be suppressed.
Second Embodiment
[0137] Next, a second embodiment of the present invention will be
described based on FIG. 8 while incorporating FIGS. 1 and 2.
[0138] FIG. 8 is a development view of an armature according to the
second embodiment, corresponding to FIG. 4. Further, the same
components as the first embodiment are designated by the same
reference numerals (this also applies to subsequent
embodiments).
[0139] In the second embodiment, basic configurations of the
reduction motor 1 are similar to the first embodiment in that, for
example, the motor is used for driving a wiper of an automobile and
includes the electric motor 2 and the speed reduction mechanism 4
connected to the rotation shaft 3 of the electric motor 2, the
electric motor 2 has the bottomed cylindrical yoke 5 and the
armature 6 rotatably installed in the yoke 5, the electric motor 2
is the four-pole six-slot eighteen-segment electric motor in which
the number of permanent magnets 7 disposed at the yoke 5 is set to
four, the number of slots 13 formed at the armature core 8 is set
to six, and the number of the segments 15 installed at the
commutator 10 is set to eighteen, the U phase, the V phase and the
W phase teeth 12 are allocated in this order in the circumferential
direction, the segments 15 having the same electric potential are
short-circuited by the connecting wire 17, the armature coil 9
wound on the teeth 12 and the connecting wire 17 are formed on the
armature core 8 or the riser 16 of the commutator 10 by winding the
wire 14 through the double flyer method, the drawing direction of
the wire 14 drawn between the armature core 8 and the commutator 10
and the wire 14 drawn to form the connecting wire 17 is set in the
same direction around the rotation shaft 3 as a whole, and so on
(this also applies to the following embodiments).
[0140] Here, the second embodiment is distinguished from the
above-mentioned first embodiment in that, in the armature coils 9U1
to 9W2 formed at the teeth 12 of the first embodiment, while the
wire 14 is connected to the predetermined segment 15 whenever the
phase coils 91a to 93f are formed, in the armature coils 9U1 to 9W2
formed at the teeth 12 of the second embodiment, the phase coils
91a to 93f wound in the same phase and the same direction are
continuously formed at the corresponding two teeth 12.
(Wire Connecting Structure of Connecting Wire, and Winding
Structure of Armature Coil)
[0141] Hereinafter, the wire connecting structure of the connecting
wire 17 and the winding structure of the armature coil 9U1 to 9W2
will be described in detail.
[0142] Further, like the above-mentioned first embodiment, winding
start positions of the wire 14 will be described as the first
segment 15 and the tenth segment 15. In addition, since a drawing
sequence of the wire 14 for which winding starts from the first
segment 15 and the wire 14 for which winding starts from the tenth
segment 15 is point-symmetrical about the rotation shaft 3, in the
following description, only the wire 14 for which winding starts
from the tenth segment 15 will be described.
[0143] The wire 14 having the winding starting end 81 wound around
the riser 16 of the tenth segment 15 is drawn to the right while
being wound around the rotation shaft 3, and then wound around the
first segment 15 having the same electric potential as the tenth
segment 15. Then, when the wire 14 is drawn from the commutator 10
toward the armature core 8, the wire 14 is drawn to the right while
being wound around the rotation shaft 3 and pulled into the slot 13
between the first and sixth teeth 12. Next, when the wire 14 is
wound on the teeth 12 N (N is a natural number of 1 or more) times,
the wire 14 is wound forward on the first tooth 12 N/6 times to
form the U phase coil 91a.
[0144] Next, the wire 14 is pulled out of the slot 13 between the
first and second teeth 12, and the wire 14 is drawn to the right
and pulled into the slot 13 between the third and fourth teeth 12.
Then, the wire 14 is wound forward on the fourth tooth 12 N/6 times
to form the U phase coil 91e. Next, the wire 14 is pulled out of
the slot 13 between the fourth and fifth teeth 12, and the wire 14
is drawn to the right while being wound around the rotation shaft 3
and wound around the riser 16 of the eleventh segment 15 adjacent
to the tenth segment 15.
[0145] Next, the wire 14 is drawn to the right while being wound
around the rotation shaft 3, and wound around the riser 16 of the
second segment 15 having the same electric potential as the
eleventh segment 15. Once more, when the wire 14 is drawn from the
commutator 10 toward the armature core 8, the wire 14 is drawn to
the right while being wound around the rotation shaft 3 and pulled
into the slot 13 between the first and sixth teeth 12. Then, the
wire 14 is wound in reverse on the sixth tooth 12 N/6 times to form
the "-W phase" coil 91f.
[0146] Next, the wire 14 is pulled out of the slot 13 between the
fifth and sixth teeth 12, and the wire 14 is drawn to the right and
pulled into the slot 13 between the third and fourth teeth 12.
Then, the wire 14 is wound in reverse on the third tooth 12 N/6
times to form the "-W phase" coil 91b. Next, the wire 14 is pulled
out of the slot 13 between the second and third teeth 12, and the
wire 14 is drawn to the right while being wound around the rotation
shaft 3 and wound around the riser 16 of the third segment 15
adjacent to the second segment 15.
[0147] Next, the wire 14 is drawn to the right while being wound
around the rotation shaft 3, and wound around the riser 16 of the
twelfth segment 15 having the same electric potential as the third
segment 15. Once more, when the wire 14 is drawn from the
commutator 10 toward the armature core 8, the wire 14 is drawn to
the right while being wound around the rotation shaft 3 and pulled
into the slot 13 between the third and fourth teeth 12. Then, the
wire 14 is wound in reverse on the third tooth 12 N/6 times to form
the "-W phase" coil 92b.
[0148] Next, the wire 14 is pulled out of the slot 13 between the
second and third teeth 12, and the wire 14 is drawn to the right
and pulled into the slot 13 between the first and sixth teeth 12.
Then, the wire 14 is wound in reverse on the sixth tooth 12 N/6
times to form the "-W phase" coil 92f. Next, the wire 14 is pulled
out of the slot 13 between the fifth and sixth teeth 12, and the
wire 14 is drawn to the right while being wound around the rotation
shaft 3 and wound around the riser 16 of the thirteenth segment 15
adjacent to the twelfth segment 15.
[0149] Next, the wire 14 is drawn to the right while being wound
around the rotation shaft 3, and wound around the riser 16 of the
fourth segment 15 having the same electric potential as the
thirteenth segment 15. Once more, when the wire 14 is drawn from
the commutator 10 toward the armature core 8, the wire 14 is drawn
to the right while being wound around the rotation shaft 3 and
pulled into the slot 13 between the first and second teeth 12.
Then, the wire 14 is wound forward on the second tooth 12 N/6 times
to form the V phase coil 91d.
[0150] Next, the wire 14 is pulled out of the slot 13 between the
second and third teeth 12, and the wire 14 is drawn to the right
and pulled into the slot 13 between the fourth and fifth teeth 12.
Then, the wire 14 is wound forward on the fifth tooth 12 N/6 times
to form the V phase coil 91c. Next, the wire 14 is pulled out of
the slot 13 between the fifth and sixth teeth 12, and the wire 14
is drawn to the right while being wound around the rotation shaft 3
and wound around the riser 16 of the fourteenth segment 15 adjacent
to the thirteenth segment 15.
[0151] Next, the wire 14 is drawn to the right while being wound
around the rotation shaft 3m and wound around the riser 16 of the
fifth segment 15 having the same electric potential as the
fourteenth segment 15. Once more, when the wire 14 is drawn from
the commutator 10 toward the armature core 8, the wire 14 is drawn
to the right while being wound around the rotation shaft 3 and
pulled into the slot 13 between the first and second teeth 12.
Then, the wire 14 is wound in reverse on the first tooth 12 N/6
times to form the "-U phase" coil 92a.
[0152] Next, the wire 14 is pulled out of the slot 13 between the
first and sixth teeth 12, and the wire 14 is drawn to the right and
pulled into the slot 13 between the fourth and fifth teeth 12.
Then, the wire 14 is wound in reverse on the fourth tooth 12 N/6
times to form the "-U phase" coil 92e. Next, the wire 14 is pulled
out of the slot 13 between the third and fourth teeth 12, and the
wire 14 is drawn to the right while being wound around the rotation
shaft 3 and wound around the riser 16 of the sixth segment 15
adjacent to the fifth segment 15.
[0153] Next, the wire 14 is drawn to the right while being wound
around the rotation shaft 3 and wound around the riser 16 of the
fifteenth segment 15 having the same electric potential as the
sixth segment 15. Once more, when the wire 14 is drawn from the
commutator 10 toward the armature core 8, the wire 14 is drawn to
the right while being wound around the rotation shaft 3 and pulled
into the slot 13 between the fourth and fifth teeth 12. Then, the
wire 14 is wound in reverse on the fourth tooth 12 N/6 times to
form the "-U phase" coil 93e.
[0154] Next, the wire 14 is pulled out of the slot 13 between the
third and fourth teeth 12, and the wire 14 is drawn to the right
and pulled into the slot 13 between the first and second teeth 12.
Then, the wire 14 is wound in reverse on the first tooth 12 N/6
times to form the "-U phase" coil 93a. Next, the wire 14 is pulled
out of the slot 13 between the first and sixth teeth 12, and the
wire 14 is drawn to the right while being wound around the rotation
shaft 3 and wound around the riser 16 of the sixteenth segment 15
adjacent to the fifteenth segment 15.
[0155] Next, the wire 14 is drawn to the right while being wound
around the rotation shaft 3 and wound around the riser 16 of the
seventh segment 15 having the same electric potential as the
sixteenth segment 15. Once more, when the wire 14 is drawn from the
commutator 10 toward the armature core 8, the wire 14 is drawn to
the right while being wound around the rotation shaft 3 and pulled
into the slot 13 between the second and third teeth 12. Then, the
wire 14 is wound forward on the third tooth 12 N/6 times to form
the W phase coil 93b.
[0156] Next, the wire 14 is pulled out of the slot 13 between the
third and fourth teeth 12, and the wire 14 is drawn to the right
and pulled into the slot 13 between the fifth and sixth teeth 12.
Then, the wire 14 is wound forward on the sixth tooth 12 N/6 times
to form the W phase coil 93f. Next, the wire 14 is pulled out of
the slot 13 between the first and sixth teeth 12, and the wire 14
is drawn to the right while being wound around the rotation shaft 3
and wound around the riser 16 of the eighth segment 15 adjacent to
the seventh segment 15.
[0157] Next, the wire 14 is drawn to the right while being wound
around the rotation shaft 3 and wound around the riser 16 of the
seventeenth segment 15 having the same electric potential as the
eighth segment 15. Once more, when the wire 14 is drawn from the
commutator 10 toward the armature core 8, the wire 14 is drawn to
the right while being wound around the rotation shaft 3 and pulled
into the slot 13 between the fifth and sixth teeth 12. Then, the
wire 14 is wound in reverse on the fifth tooth 12 N/6 times to form
the "-V phase" coil 92c.
[0158] Next, the wire 14 is pulled out of the slot 13 between the
fourth and fifth teeth 12, and the wire 14 is drawn to the right
and pulled into the slot 13 between the second and third teeth 12.
Then, the wire 14 is wound in reverse on the second tooth 12 N/6
times to form a "-W phase" coil 92d. Next, the wire 14 is pulled
out of the slot 13 between the first and second teeth 12, and the
wire 14 is drawn to the right while being wound around the rotation
shaft 3 and wound around the riser 16 of the eighteenth segment 15
adjacent to the seventeenth segment 15.
[0159] Next, the wire 14 is drawn to the right while being wound
around the rotation shaft 3 and wound around the riser 16 of the
ninth segment 15 having the same electric potential as the
eighteenth segment 15. Once more, when the wire 14 is drawn from
the commutator 10 toward the armature core 8, the wire 14 is drawn
to the right while being wound around the rotation shaft 3 and
pulled into the slot 13 between the second and third teeth 12.
Then, the wire 14 is wound in reverse on the second tooth 12 N/6
times to form the "-V phase" coil 93d.
[0160] Next, the wire 14 is pulled out of the slot 13 between the
first and second teeth 12, and the wire 14 is drawn to the right
and pulled into the slot 13 between the fifth and sixth teeth 12.
Then, the wire 14 is wound in reverse on the fifth tooth 12 N/6
times to form the "-V phase" coil 93c. Next, the wire 14 is pulled
out of the slot 13 between the fourth and fifth teeth 12, the wire
14 is drawn to the right while being wound around the rotation
shaft 3 and wound around the riser 16 of the tenth segment 15
adjacent to the ninth segment 15, and the winding terminating end
82 of the wire 14 is connected to the tenth segment 15.
[0161] Accordingly, the armature coil 9U1 of the U phase
constituted by the U phase coil 91a, the "-U phase" coil 92a and
the "-U phase" coil 93a and wound N/2 times is formed at the first
tooth 12. In addition, the armature coil 9W1 of the W phase
constituted by the "-W phase" coil 91b, the "-W phase" coil 92b and
the W phase coil 93b and wound N/2 times is formed at the third
tooth 12. Further, the armature coil 9V1 of the V phase constituted
by the V phase coil 91c, the "-V phase" coil 92c and the "-V phase"
coil 93c and wound N/2 times is formed at the fifth tooth 12.
[0162] Then, the phase coils 91a to 93f having the same phase and
wound in the same direction are continuously formed on the
corresponding two teeth 12.
[0163] The wire 14 having the winding starting end 81 wound around
the riser 16 of the first segment 15 is drawn along with the wire
14 having the winding starting end 81 wound around the riser 16 of
the above-mentioned tenth segment 15 and point-symmetrically with
respect to the rotation shaft 3. Then, the armature coils 9U1 to
9W2 of the phases wound N/2 times are formed.
[0164] Accordingly, the armature coil 9 is configured of the
armature coils 9U1 and 9U2 of the U phase formed at the first and
fourth teeth 12, the armature coils 9V1 and 9V2 of the V phase
formed at the second and fifth teeth 12, and the armature coils 9W1
and 9W2 of the W phase formed at the third and sixth teeth 12, and
the number of parallel circuits is four.
[0165] Here, when the number times N that the wire 14 of each phase
of the armature coils 9U1 to 9W2 is wound is an odd number, a
number of winding times may be increased by one turn in one of
winding processes in which the winding is started from the first
segment 15 or started from the tenth segment 15, and the number of
winding times may be reduced by one turn in the other of the
winding processes.
[0166] Accordingly, in the above-mentioned second embodiment, the
same effect as the above-mentioned first embodiment is
obtained.
Third Embodiment
[0167] Next, a third embodiment of the present invention will be
described based on FIGS. 9 and 10.
[0168] FIG. 9 is a plan view of a brush-receiving portion according
to the third embodiment, corresponding to FIG. 3. In addition, FIG.
10 is a development view of an armature according to the third
embodiment, corresponding to FIG. 4.
[0169] As shown in FIGS. 9 and 10, the third embodiment is
distinguished from the above-mentioned first embodiment in that, in
the first embodiment, while the brushes 21 are configured of three
brushes 21, i.e., the low speed brush 21a and the high speed brush
21b connected to the positive electrode side and the common brush
21c used in common with the low speed brush 21a and the high speed
brush 21b and connected to the negative electrode side, in the
third embodiment, brushes 121 are configured of two brushes 121,
i.e., a positive electrode-side brush 121a connected to the
positive electrode side and a negative electrode-side brush 121b
connected to the negative electrode side.
[0170] The positive electrode-side brush 121a and the negative
electrode-side brush 121b are disposed at an interval of an
electrical angle of 180.degree., i.e., an interval of a mechanical
angle of 90.degree. in the circumferential direction.
[0171] When the reduction motor 1 having the above-mentioned
configuration is used for driving, for example, a wiper of an
automobile, wiper blades are reciprocated using two reduction
motors 1. Accordingly, the same effect as the above-mentioned first
embodiment can be obtained. In addition, a reciprocating
sweeping-out range in which the wiper blades are disposed between a
lower inversion position and an upper inversion position can be
adjusted, or a receiving position of the wiper upon non-use of the
wiper blade can be set further inside a vehicle body than the lower
inversion position of the wiper upon use of the wiper to improve
aesthetic properties of the entire automobile.
[0172] Further, the present invention is not limited to the
above-mentioned embodiments, but various modifications may be added
to the above-mentioned embodiments without departing from the
spirit of the present invention.
[0173] For example, in the above-mentioned second embodiment, the
case in which the phase coils 91a to 93f are formed while winding
the wire 14 on each of the teeth 12 N/6 times through the double
flyer method has been described. However, the present invention is
not limited thereto, but the phase coils 91a to 93f may be formed
by winding the wire 14 on each of the teeth 12 N/3 times through a
single flyer method. That is, the phase coils 91a to 93f may be
formed at the teeth 12 at a time. In the configuration described
above, the number of parallel circuits is two.
Fourth Embodiment
(Reduction Motor)
[0174] Next, a fourth embodiment of the present invention will be
described based on FIGS. 11 to 18.
[0175] FIG. 11 is a longitudinal cross-sectional view of a
reduction motor to which the electric motor according to the
present invention is applied.
[0176] As shown in FIG. 11, a reduction motor 101 is used for, for
example, a wiper for an automobile, and includes an electric motor
102 and a speed reduction mechanism 104 connected to a rotation
shaft 103 of the electric motor 102. The electric motor 102 has a
bottomed cylindrical yoke 105, and an armature 106 rotatably
installed in the yoke 105.
[0177] A cylindrical portion 153 of the yoke 105 is formed in a
substantially cylindrical shape, and four segment-type magnets 107
are disposed at an inner circumferential surface of the cylindrical
portion 153. Further, the magnet 107 is not limited to the segment
type but a ring type may be used.
[0178] A bearing housing 119 protruding outward in the axial
direction from a center in the radial direction is formed at a
bottom wall (an end portion) 151 of the yoke 105, and a sliding
bearing 118 configured to rotatably and axially support one end of
the rotation shaft 103 is installed at the bearing houding 119. The
sliding bearing 118 has a centering function of the rotation shaft
103.
[0179] An outer flange portion 152 is installed at an opening
portion 153a of the cylindrical portion 153. A bolt hole (not
shown) is formed in the outer flange portion 152. As a bolt (not
shown) is inserted through the bolt hole and threadedly inserted
into a bolt hole (not shown) formed in a gear housing 123 (to be
described below) of the speed reduction mechanism 104, the yoke 105
is fastened and fixed to the speed reduction mechanism 104.
[0180] FIG. 12 is a perspective view of the armature, and FIG. 13
is a plan view of the armature core that constitutes the
armature.
[0181] As shown in FIGS. 11 to 13, the armature 106 includes an
armature 180 fitted and fixed onto the rotation shaft 103, and a
commutator 110 disposed at the other end (the speed reduction
mechanism 104 side) of the rotation shaft 103.
[0182] The armature 180 has an armature core 108, an armature coil
109 formed at the armature core 108, and an insulator 160
configured to insulate the armature core 108 and the armature coil
109.
[0183] The armature core 108 is formed by stacking a magnetic plate
member punched by pressing in the axial direction (a stacked core)
or pressure-forming a soft magnetic powder (a pressed powder core),
and has a substantially columnar core main body 111.
[0184] As shown in FIG. 13, a through-hole 111a into which the
rotation shaft 103 is press-fitted is formed at substantially a
center in the radial direction of the core main body 111. In
addition, six teeth 112 are installed at an outer circumferential
portion of the core main body 111. Each of the teeth 112 is formed
in substantially a T shape when seen from a plan view in the axial
direction, and configured of a winding drum 112a radially
protruding from the core main body 111 in the radial direction, and
a flange 112b extending from a front end of the winding drum 112a
in the circumferential direction and constituting an outer
circumference of the armature core 108.
[0185] According to the above-mentioned configuration, six dovetail
groove-shaped slots 113 are formed between the neighboring teeth
112. A wire 114 passes through these slots 113, and the wire 114 is
wound on the winding drum 112a of the teeth 112 to form the
armature coil 109 (a method of forming the armature coil 109 will
be described below in detail).
[0186] As shown in FIGS. 11 and 12, eighteen segments 115 formed of
a conductive material are attached to the outer circumferential
surface of the commutator 110 fitted and fixed onto the other end
side closer than the rotation shaft 103 from the armature core 108.
The segments 115 are formed of a plate-shaped metal piece elongated
in the axial direction, and are insulated from each other and fixed
in the circumferential direction in parallel at equal
intervals.
[0187] In this way, the electric motor 102 is constituted by a
four-pole six-slot eighteen-segment electric motor in which the
number of magnetic poles is four, the number of slots 113 is six
and the number of segments 115 is eighteen.
[0188] In addition, a riser 116 folded to an outer diameter side is
integrally formed with an end portion of the armature core 108 side
of each of the segments 115. A terminal portion of the armature
coil 109 is wound around the riser 116 and fixed thereto through
fusing or the like. Accordingly, the segment 115 is electrically
connected to the armature coil 109 corresponding thereto.
[0189] Further, a connecting wire 117 is wound around the riser 116
corresponding to the segments 115 having the same electric
potential, and the connecting wire 117 is fixed to the riser 116
through fusing. The connecting wire 117 is configured to
short-circuit the segments 115 having the same electric potential
to be drawn between the commutator 110 and the armature core
108.
[0190] As shown in FIG. 11, the commutator 110 having the
above-mentioned configuration faces the gear housing 123 of the
speed reduction mechanism 104. The gear housing 123 is configured
of a housing main body 142 formed in substantially a box shape
having an opening portion 142a formed at one surface thereof
through aluminum die-casting, and a bottom plate 143 formed of a
resin and configured to close the opening portion 142a of the
housing main body 142.
[0191] A gear group 141 of the speed reduction mechanism 104 is
received in the housing main body 142. In addition, a
brush-receiving portion 122 is integrally formed with the electric
motor 102 side of the housing main body 142, and the commutator 110
of the electric motor 102 faces the brush-receiving portion
122.
[0192] The brush-receiving portion 122 is formed in a concave shape
at the electric motor 102 side of the gear housing 123. A holder
stay 134 is installed inside the brush-receiving portion 122. A
plurality of brush holders (not shown) are installed at the holder
stay 134, and the brushes 121 are received to protrude from and
retract into the brush holders. The brush 121 is configured to
supply power from an external power supply (for example, a battery
or the like mounted in an automobile) to the commutator 110. The
brush 121 is biased toward the commutator 110 by a spring (not
shown), and has a front end that comes in sliding contact with the
segments 115.
(Method of Forming Armature Coil)
[0193] Next, an example of a method of forming the armature coil
109 will be described based on FIG. 14.
[0194] FIG. 14 is a development view of the armature, and a gap
between the neighboring teeth forms a slot. Further, in description
of FIG. 14, the segments 115, the teeth 112, and the formed
armature coils 109 are designated by reference numerals.
[0195] As shown in FIG. 14, in the teeth 112, the U phase, the V
phase and the W phase are sequentially allocated in the
circumferential direction in this order. That is, the first and
fourth teeth 112 are the U phase, the second and fifth teeth 112
are the V phase, and the third and sixth teeth 112 are the W phase.
Here, in reference numerals designated to the segments 115, a
position corresponding to No. 1 is a position corresponding to the
first tooth 112.
[0196] Further, in FIG. 14, the clockwise winding direction of the
wire 114 on the teeth 112 is hereinafter referred to as "forward",
and the counterclockwise winding direction is hereinafter referred
to as "reverse".
[0197] First, for example, after winding of a winding starting end
114a of the wire 114 starts on the first segments 115, the wire 114
is pulled into the slot 113 between the first and sixth teeth 112
in the vicinity of the first segment 115. Then, when the wire 114
is wound on each of the teeth 112 n (n is a natural number,
multiples of 3), the wire 114 is wound forward on the first tooth
112 n/3 times through the concentrated winding method.
[0198] Next, the wire 114 is pulled out of the slot 113 between the
first and second teeth 112 and wound around the riser 116 of the
second segments 115 adjacent to the first segment 115. Then, a
winding terminating end 114b is connected to the second segment
115. Accordingly, a first coil 191 of a U phase wound forward on
the first tooth 112 is formed between the first and second segments
115.
[0199] In addition, the wire 114 having the winding starting end
114a wound around the riser 116 of the fifth segment 115 is pulled
into the slot 113 between the first and second teeth 112. Then, the
wire 114 is wound in reverse on the first tooth 112 n/3 times
through the concentrated winding method.
[0200] Next, the wire 114 is pulled out of the slot 113 between the
first and sixth teeth 112, and wound around the riser 116 of the
sixth segment 115 adjacent to the fifth segment 115. Then, the
winding terminating end 114b is connected to the sixth segment 115.
Accordingly, a second coil 192 of a "-U" phase wound in reverse on
the first tooth 112 is formed between the fifth and sixth segments
115.
[0201] Further, the wire 114 having the winding starting end 114a
wound around the riser 116 of the sixth segment 115 is pulled into
the slot 113 between the first and second teeth 112. Then, the wire
114 is wound in reverse on the first tooth 112 n/3 times through
the concentrated winding method.
[0202] Next, the wire 114 is pulled out of the slot 113 between the
first and sixth teeth 112 and wound around the riser 116 of the
seventh segment 115 adjacent to the sixth segment 115. Then, the
winding terminating end 114b is connected to the seventh segment
115. Accordingly, a third coil 193 of a "-U" phase wound in reverse
on the first tooth 112 is formed between the sixth and seventh
segments 115.
[0203] Accordingly, the armature coil 109 wound by n turns and
configured of the first coil 191 of the U phase in which the wire
114 is wound forward n/3 times, and the second coil 192 of the "-U"
phase and the third coil 193 of the "-U" phase in which the wire
114 is wound in reverse n/3 times is formed at the first tooth 112
corresponding to the U phase.
[0204] Then, as these are sequentially performed between the
segments 115 corresponding to the phases, the armature coil 109
having a 3-phase structure including the first coil 191, the second
coil 192 and the third coil 193 is formed at the armature core 108,
and the coils 191 to 193 having the U, "-W," "-W," V, "-U," "-U,"
W, "-V" and "-V" phases are electrically connected in sequence
between the neighboring segments 115.
[0205] Further, places at which the winding starting end 114a and
the winding terminating end 114b of the wire 114 forming the coils
191 to 193 of the phases connect to the segments 115 may be
disposed such that the coils 191 to 193 of the U, "-W," "-W," V,
"-U," "-U," W, "-V" and "-V" phases may be electrically connected
between the neighboring segments 115 in this order.
[0206] Here, the insulators 160 formed of a resin are mounted on
the armature core 108 from both ends in the axial direction, and
the wire 114 is wound from above the two insulators 160.
(Insulator)
[0207] FIG. 15 is a perspective view showing a state in which an
insulator is mounted on the armature core, FIG. 16 is an enlarged
perspective view of the insulator mounted on the armature core when
seen from the commutator side, and FIG. 17 is a perspective view of
the insulator.
[0208] As shown in FIGS. 15 to 17, the insulator 160 includes a
core main body coating portion 161 configured to cover the core
main body 111 of the armature core 108, and a tooth coating portion
162 configured to cover the teeth 112. The core main body coating
portion 161 and the tooth coating portion 162 are integrally formed
of an insulating material such as a resin or the like.
[0209] The core main body coating portion 161 has a main body
coating portion end surface 161a configured to cover an end portion
in the axial direction of the core main body 111, and a main body
coating portion side surface 161b configured to cover an outer
circumferential surface of the core main body 111. A substantially
cylindrical shaft insertion portion 163 protrudes outward in the
axial direction from a center in the radial direction of the main
body coating portion end surface 161a. The rotation shaft 103 is
inserted through the shaft insertion portion 163.
[0210] The main body coating portion side surface 161b extends from
an outer circumferential edge portion of the main body coating
portion end surface 161a to substantially a center in the axial
direction of the armature core 108.
[0211] The tooth coating portion 162 has a tooth coating portion
end surface 162a configured to cover an end portion in the axial
direction of the teeth 112, and a tooth coating portion side
surface 162b configured to cover side surfaces of the teeth
112.
[0212] The tooth coating portion end surface 162a is formed in
substantially a T shape when seen in a plan view in the axial
direction to correspond to shapes of the teeth 112. Specifically,
the tooth coating portion end surface 162a has a winding drum
coating portion end surface 164a configured to cover an end surface
in the axial direction of the winding drum 112a of the teeth 112,
and a flange coating portion end surface 164b configured to cover
an end surface in the axial direction of the flange 112b, which are
integrally formed with each other.
[0213] The tooth coating portion side surface 162b is formed in
substantially an L-shaped cross section, and extends from side
edges of the winding drum coating portion end surface 164a and side
edges inside in the radial direction of the flange coating portion
end surface 164b in the tooth coating portion end surface 162a to
substantially a center in the axial direction of the armature core
108. More specifically, the tooth coating portion side surface 162b
has a winding drum coating portion side surface 165a configured to
cover side surfaces of the winding drum 112a of the teeth 112, and
a flange coating portion side surface 165b configured to cover an
inner surface in the radial direction of the flange 112b, which are
integrally formed with each other.
[0214] Here, the two partition walls 166 and 167 of a first
partition wall 166 and a second partition wall 167 having a plate
shape are integrally formed with the tooth coating portion end
surface 162a and the tooth coating portion side surface 162b
throughout the entire circumference. Then, the first partition wall
166 is disposed at substantially a center in the radial direction
of the tooth coating portion 162. Further, the second partition
wall 167 is disposed at substantially a center between the first
partition wall 166, and the flange coating portion end surface 164b
and the flange coating portion side surface 165b. In addition, flat
chamfering portions 168 are formed at corners of the partition
walls 166 and 167.
[0215] Here, the two partition walls 166 and 167 are provided such
that places of the tooth coating portion 162 on which the wire 114
is wound are divided into three chambers. Accordingly, three
accommodating portions 171, 172 and 173 in which the three coils
191, 192 and 193 are accommodated are formed at the tooth coating
portion 162.
[0216] That is, the first accommodating portion 171 of the three
accommodating portions 171, 172 and 173 is formed inside in the
radial direction of the first partition wall 166 of the tooth
coating portion 162. Then, the first coil 191 is accommodated in
the first accommodating portion 171. In addition, the second
accommodating portion 172 of the three accommodating portions 171,
172 and 173 is formed between the first partition wall 166 and the
second partition wall 167 of the tooth coating portion 162. Then,
the second coil 192 is accommodated in the second accommodating
portion 172. Further, the third accommodating portion 173 of the
three accommodating portions 171, 172 and 173 is formed outside in
the radial direction of the second partition wall 167 of the tooth
coating portion 162. Then, the third coil 193 is accommodated in
the third accommodating portion 173.
[0217] In this way, the three coils 191, 192 and 193 are
accommodated in the three accommodating portions 171, 172 and 173
inside in the radial direction in sequence in which the coils are
formed. That is, first, the wire 114 is wound on the first
accommodating portion 171 to form a first coil 181. Next, the wire
114 is wound on the second accommodating portion 172 to form a
second coil 182. Next, the wire 114 is wound on the third
accommodating portion 173 to form a third coil 183.
[0218] Here, since the flat chamfering portions 168 are formed at
the corners of the partition walls 166 and 167, when the coils 191
to 193 are accommodated in the three accommodating portions 171,
172 and 173, winding workability of the wire 114 forming the coils
191 to 193 is improved. That is, winding work of the wire 114 can
be smoothly performed by the flat chamfering portion 168 without
hooking the wire 114 on the partition walls 166 and 167.
[0219] In addition, a winding collapse prevention plate 169 is
integrally formed with a connecting portion of the winding drum
coating portion end surface 164a of the tooth coating portion 162
and the main body coating portion end surface 161a of the core main
body coating portion 161. The winding collapse prevention plate 169
is configured to prevent collapse of the first coil 191
accommodated in the first accommodating portion 171. The winding
collapse prevention plate 169 also has a function of dividing the
first accommodating portion 171.
[0220] Further, a winding collapse prevention convex portion 170 is
integrally formed with the flange coating portion end surface 164b
of the tooth coating portion 162 at substantially a center in the
circumferential direction. The winding collapse prevention convex
portion 170 is configured to prevent collapse of the third coil 193
accommodated in the third accommodating portion 173. The winding
collapse prevention convex portion 170 also has a function of
dividing the third accommodating portion 173.
[0221] Here, the partition walls 166 and 167, the winding collapse
prevention plate 169 and the winding collapse prevention convex
portion 170 are formed to satisfy the following relations.
[0222] FIG. 18 is a view for describing relations between the
partition wall, the winding collapse prevention plate and the
winding collapse prevention convex portion.
[0223] That is, as shown in FIG. 18, when a height of the winding
collapse prevention plate 169 is set as T1, a height of the first
partition wall 166 is set as T2, and a height of the second
partition wall 167 and a height of the winding collapse prevention
convex portion 170 is set as T3, the heights T1, T2 and T3 are set
to satisfy:
T1.ltoreq.T2T3 (1)
[0224] Further, when a distance between the winding collapse
prevention plate 169 and the first partition wall 166 is set as L1,
a distance between the first partition wall 166 and the second
partition wall 167 is set as L2, and a distance between the second
partition wall 167 and the winding collapse prevention convex
portion 170 is set as L3, the distances L1, L2 and L3 are set to
satisfy:
L1.gtoreq.L2.gtoreq.L3 (2)
[0225] Then, when a capacity (see a portion hatched by solid lines)
of the first accommodating portion 171 formed by the winding
collapse prevention plate 169, the tooth coating portion 162 and
the first partition wall 166 is set as Y1, a capacity (see a
portion hatched by two-dot chain lines) of the second accommodating
portion 172 formed by the first partition wall 166, the tooth
coating portion 162 and the second partition wall 167 is set as Y2,
and a capacity (see a portion hatched by chain lines) of the third
accommodating portion 173 formed by the second partition wall 167,
the tooth coating portion 162 and the winding collapse prevention
convex portion 170 is set as Y3, the capacities Y1, Y2 and Y3 are
set to satisfy:
Y1.apprxeq.Y2.apprxeq.Y3 (3)
[0226] In order to satisfy equations (1) and (2), as the partition
walls 166 and 167, the winding collapse prevention plate 169 and
the winding collapse prevention convex portion 170 are formed, a
wire height can be suppressed to a low level as the coils 191 to
193 are disposed inside in the radial direction. That is, the wire
height of the first coil 191 of the three coils 191 to 193 is
maximally reduced, and the wire height of the third coil 193 is
maximally increased.
[0227] Here, as specifically shown in FIG. 13, since the teeth 112
radially extend from the armature core 108, a distance between the
neighboring teeth 112 disposed inside in the radial direction is
reduced. For this reason, as the wire height is suppressed to a low
level as the coils 191 to 193 are disposed inside in the radial
direction, contact between the neighboring coils 191 to 193 in the
circumferential direction is avoided. In addition, as the capacity
Y1 of the first accommodating portion 171, the capacity Y2 of the
second accommodating portion 172 and the capacity Y3 of the third
accommodating portion 173 satisfy equation (3), lengths of the
wires 114 forming the three coils 191 to 193 can be
uniformized.
(Speed Reduction Mechanism)
[0228] Returning to FIG. 11, the gear group 141 is received in the
housing main body 142 of the gear housing 123 to which the electric
motor 102 is attached. The gear group 141 is configured of a worm
shaft 125 connected to the rotation shaft 103 of the electric motor
102, a stepped gear 126 meshed with the worm shaft 125, and a spur
gear 127 meshed with the stepped gear 126.
[0229] The worm shaft 125 has one end connected to the rotation
shaft 103 and the other end rotatably and axially supported by the
housing main body 142. A connecting portion 124 of the worm shaft
125 and the rotation shaft 103, i.e., the other end of the rotation
shaft 103, is rotatably supported by a roll bearing 132 installed
at the housing main body 142.
[0230] An output shaft 128 is installed at the spur gear 127, and a
front end of the output shaft 128 protrudes from the housing main
body 142. In addition, a tapered portion 129 is formed at the front
end of the output shaft 128, and further, a serration 130 is formed
at the tapered portion 129. For example, the serration 130 is used
to connect an external mechanism configured to drive a wiper or the
like to the output shaft 128.
(Operation of Electric Motor)
[0231] Next, an operation of the electric motor 102 will be
described based on FIG. 14.
[0232] In description of the operation of the electric motor 102,
for example, as shown in FIG. 14, the case in which the brush 121
is disposed between the first and second segments 115, the brush
121 is disposed at the sixth segment 115, and a voltage is applied
between the two brushes 121 will be described.
[0233] In this case, the first coil 191 of the U phase is
short-circuited. Then, a reverse current (counterclockwise in FIG.
14) flows through the second coil 192 of the "-U" phase, and a
forward current (clockwise in FIG. 14) flows through the third coil
193 of the "-U" phase. That is, since currents in opposite
directions flow through the second coil 192 and the third coil 193,
the magnetic fields are offset and no torque is generated between
the coils and the magnets 107.
[0234] On the other hand, forward currents flow through the first
coil 191 of the V phase, the second coil 192 of the "-V" phase and
the third coil 193 of the "-V" phase. In addition, reverse currents
flow through the first coil 191 of the "-W" phase, the second coil
192 of the "-W" phase and the third coil 193 of the "-W" phase.
[0235] Then, the magnetic fields are formed at the second, third,
fifth and sixth teeth 112. Directions of the magnetic fields are
provided in sequence in the circumferential direction. For this
reason, the magnetic attractive force or repulsive force is applied
between the magnetic field formed at each of the teeth 112 and the
magnet 107 about the rotation shaft 103 at the point-symmetrical
positions in the same direction. Then, the rotation shaft 103 is
rotated accordingly.
[0236] Further, for example, in the description of the operation of
the above-mentioned electric motor 102, the brush 121 disposed
between the first and second segments 115 is angularly advanced,
and the rotation shaft 103 can also be rapidly rotated.
(Effects)
[0237] Accordingly, according to the above-mentioned fourth
embodiment, since the first partition wall 166 and the second
partition wall 167 are installed at the tooth coating portion 162
of the insulator 160 mounted on the armature core 108 to form the
three accommodating portions 171, 172 and 173 as the wire 114 is
formed at the armature core 108 to form the armature coil 109,
places at which the three coils 191 to 193 that constitute the
armature coil 109 are disposed can be divided. For this reason, as
a winding work of the wire 114 can be easily performed, thickening
of the winding of the wire 114 can also be reduced.
[0238] In addition, the three coils 191 to 193 are accommodated in
the three accommodating portions 171, 172 and 173 inside in the
radial direction according to the sequence in which the three coils
are formed. That is, first, the wire 114 is wound on the first
accommodating portion 171 to form the first coil 181. Next, the
wire 114 is wound on the second accommodating portion 172 to form
the second coil 182. Next, the wire 114 is wound on the third
accommodating portion 173 to form the third coil 183. For this
reason, in comparison with the case in which the wire 114 is
sequentially wound from the distal end of the teeth 112, the coils
191 to 193 can be smoothly formed on the teeth 112. Thus, the wire
114 can be prevented from becoming bulky, and thickening of the
winding of the wire 114 can be securely reduced.
[0239] Further, since the flat chamfering portions 168 are formed
at corners of the partition walls 166 and 167, when the coils 191
to 193 are accommodated in the three accommodating portions 171,
172 and 173, winding workability of the wire 114 forming the coils
191 to 193 can be improved. That is, the winding work of the wire
114 can be more smoothly performed without the wire 114 hooking on
the partition walls 166 and 167 by the flat chamfering portions
168.
[0240] In addition, the two partition walls 166 and 167 of the
first partition wall 166 and the second partition wall 167 are
integrally formed with the tooth coating portion end surface 162a
and the tooth coating portion side surface 162b throughout the
entire circumference. For this reason, places at which the three
coils 191 to 193 are disposed can be securely divided, the winding
workability of the wire 114 can be more easily performed, and
thickening of the winding of the wire 114 can also be securely
reduced.
[0241] Further, since the winding collapse prevention plate 169 is
integrally formed with the connecting portion of the winding drum
coating portion end surface 164a of the tooth coating portion 162
and the main body coating portion end surface 161a of the core main
body coating portion 161, collapse of the first coil 191
accommodated in the first accommodating portion 171 can be securely
prevented. In addition, since the winding collapse prevention
convex portion 170 is integrally formed with the flange coating
portion end surface 164b of the tooth coating portion 162 at
substantially a center in the circumferential direction, collapse
of the third coil 193 accommodated in the third accommodating
portion 173 can be prevented.
[0242] In addition, since the partition walls 166 and 167, the
winding collapse prevention plate 169 and the winding collapse
prevention convex portion 170 are formed to satisfy equations (1)
to (3), a wire height of the first coil 191 of the three coils 191
to 193 can be maximally reduced, and a wire height of the third
coil 193 can be maximally increased.
[0243] For this reason, the wire 114 can be efficiently wound on
the teeth 112 while avoiding contact between the coils 191 to 193
neighboring in the circumferential direction. Thus, a space factor
of the wire 114 can be improved. Further, the lengths of the wires
114 forming the three coils 191 to 193 can be uniformized, and
characteristics of the electric motor 102 can be stabilized.
[0244] Further, in the above-mentioned fourth embodiment, the case
in which the winding collapse prevention plate 169 is integrally
formed with the connecting portion of the winding drum coating
portion end surface 164a of the tooth coating portion 162 and the
main body coating portion end surface 161a of the core main body
coating portion 161 has been described.
[0245] In addition, in the above-mentioned fourth embodiment, the
case in which the two partition walls 166 and 167 of the first
partition wall 166 and the second partition wall 167 are integrally
formed with the tooth coating portion end surface 162a and the
tooth coating portion side surface 162b throughout the entire
circumference.
[0246] However, the present invention is not limited thereto, but
for example, may be configured like the following modified
examples.
First Modified Example
[0247] FIG. 19 is a perspective view of a state in which an
insulator is mounted on an armature core according to a first
modified example of the fourth embodiment.
[0248] As shown in FIG. 19, the above-mentioned fourth embodiment
and the first modified example differ in that, in the insulator 160
of the above-mentioned fourth embodiment, while the winding
collapse prevention plate 169 is integrally formed with the
connecting portion of the winding drum coating portion end surface
164a of the tooth coating portion 162 and the main body coating
portion end surface 161a of the core main body coating portion 161,
in the first modified example, the winding collapse prevention
plate 169 is not integrally formed therewith.
[0249] The first accommodating portion 171 is disposed at the most
inside portion in the radial direction of the three accommodating
portions 171, 172 and 173. That is, the first accommodating portion
171 is formed at a root of the tooth 112, and collapse of the first
coil 191 accommodated in the first accommodating portion 171 is
suppressed by the first partition wall 166 and the main body
coating portion side surface 161b.
[0250] Accordingly, even with the configuration of the first
modified example, the same effect as in the above-mentioned fourth
embodiment can be obtained.
Second Modified Example
[0251] FIG. 20 is a perspective view of a state in which an
insulator is mounted on an armature core according to a second
modified example of the fourth embodiment.
[0252] As shown in FIG. 20, the above-mentioned fourth embodiment
and the second modified example differ in that, in the fourth
embodiment, while the first partition wall 166 and the second
partition wall 167 are integrally formed with the tooth coating
portion end surface 162a and the tooth coating portion side surface
162b throughout the entire circumference, in the second modified
example, a first partition wall 366 and a second partition wall 367
having plate shapes are formed at only the tooth coating portion
end surface 162a.
[0253] Even with the above-mentioned configuration, places at which
the coils 191 to 193 are disposed can be divided. For this reason,
the same effect as in the above-mentioned fourth embodiment can be
exhibited.
Third Modified Example
[0254] FIG. 21 is a perspective view of a state in which an
insulator is mounted on an armature core according to a third
modified example of the fourth embodiment.
[0255] As shown in FIG. 21, the second modified example and the
third modified example differ in that, in the above-mentioned
second modified example, while the winding collapse prevention
plate 169 is integrally formed with the connecting portion of the
winding drum coating portion end surface 164a of the tooth coating
portion 162 and the main body coating portion end surface 161a of
the core main body coating portion 161, in the third modified
example, the winding collapse prevention plate 169 is not
integrally formed therewith.
[0256] Here, as described in the first modified example, the first
accommodating portion 171 partitioned by the winding collapse
prevention plate 169 is disposed at a root of the tooth 112. For
this reason, the first coil 191 accommodated in the first
accommodating portion 171 suppresses the collapse by the first
partition wall 166 and the main body coating portion side surface
161b.
[0257] Accordingly, even with the configuration of the third
modified example, the same effect as in the above-mentioned second
modified example can be exhibited.
Fifth Embodiment
[0258] Next, a fifth embodiment of the present invention will be
described based on FIGS. 22 to 24. Further, the same elements as in
the fourth embodiment will be described with the same reference
numerals.
[0259] FIG. 22 is a development view of the armature according to
the fifth embodiment.
[0260] As shown FIG. 22, the fourth embodiment and the fifth
embodiment differ in that, while the eighteen segments 115 are
attached to the commutator 110 of the fourth embodiment, twelve
segments 115 are attached to a commutator 210 of the fifth
embodiment. That is, an electric motor 202 of the fifth embodiment
is configured of a four-pole six-slot twelve-segment electric motor
in which the number of magnetic poles is set to 4, the number of
slots 113 is set to 6, and the number of segments 115 is set to
12.
[0261] In addition, while the armature coil 109 having a
three-phase structure including the three coils 191 to 193 of the
first coil 191, the second coil 192 and the third coil 193 is
formed at the armature core 108 configuring the armature 180 of the
fourth embodiment, an armature coil 209 having a three-phase
structure including the two coils 291 and 292 of a first coil 291
and a second coil 292 is formed at the armature core 108
configuring an armature 280 of the fifth embodiment.
[0262] Further, a shape of an insulator 260 configured to insulate
the armature coil 209 and the armature core 108 is distinguished
from the shape of the insulator 160 of the fourth embodiment as a
shape of the armature coil 209 is varied.
[0263] This will be more specifically described below.
(Method of Forming Armature Coil)
[0264] First, an example of a method of forming the armature coil
209 according to the fifth embodiment will be described based on
FIG. 22.
[0265] As shown in FIG. 22, the teeth 112 are allocated of the U
phase, the V phase and the W phase in the circumferential direction
in this order. That is, the first and fourth teeth 112 have the U
phase, the second and fifth teeth 112 have the V phase, and the
third and sixth teeth 112 have the W phase.
[0266] Here, a position corresponding to No. 1 of the numbers
designated to the segments 115 is a position corresponding to the
first tooth 112. In addition, the segments 115 having the same
electric potential are short-circuited by the connecting wire
117.
[0267] Further, in FIG. 22, a clockwise winding direction of the
wire 114 on the teeth 112 is referred to as forward, and a
counterclockwise winding direction is referred to as reverse.
[0268] First, for example, after winding of the winding starting
end 114a of the wire 114 on the first segments 115 starts, the wire
114 is pulled into the slot 113 between the first and sixth teeth
112 adjacent to the first segments 115. Then, when the wire 114 is
wound on each of the teeth 112 n (n is a natural number, multiples
of 2), the wire 114 is wound forward on the first tooth 112 n/2
times through the concentrated winding method.
[0269] Next, the wire 114 is pulled out of the slot 113 between the
first and second teeth 112, and wound around the riser 116 of the
second segments 115 adjacent to the first segment 115. Then, the
winding terminating end 114b is connected to the second segments
115. Accordingly, the first coil 291 of the U phase wound forward
on the first tooth 112 is formed between the first and second
segments 115.
[0270] In addition, the wire 114 having the winding starting end
114a wound around the riser 116 of the fourth segments 115 is
pulled into the slot 113 between the first and second teeth 112.
Then, the wire 114 is wound in reverse on the first tooth 112 n/2
times through the concentrated winding method.
[0271] Next, the wire 114 is pulled out of the slot 113 between the
first and sixth teeth 112, and wound around the riser 116 of the
fifth segments 115 adjacent to the fourth segments 115. Then, the
winding terminating end 114b is connected to the fifth segments
115. Accordingly, the second coil 292 of the "-U" phase wound in
reverse on the first tooth 112 is formed between the fourth and
fifth segments 115.
[0272] Accordingly, the armature coil 209 wound n times and
configured of the first coil 191 of the U phase on which the wire
114 is wound forward n/2 times and the second coil 192 of the "-U"
phase on which the wire 114 is wound in reverse n/2 times is formed
at the first tooth 112 corresponding to the U phase.
[0273] Then, as these are sequentially performed between the
segments 115 corresponding to the phases, the armature coil 209 of
the three-phase structure including the first coil 291 and the
second coil 292 is formed at the armature core 108, and the coils
291 and 292 of the U, "-W," V, "-U," W and "-V" phases are
electrically connected between the neighboring segments 115 in this
order.
[0274] Further, places at which the winding starting end 114a and
the winding terminating end 114b of the wire 114 forming the coils
291 and 292 of the phases are connected to the segments 115 may be
provided such that the coils 291 and 292 of the U, "-W," V, "-U," W
and "-V" phases are electrically connected between the neighboring
segments 115 in this order.
(Insulator)
[0275] FIG. 23 is a perspective view of a state in which the
insulator is mounted on the armature core.
[0276] As shown in FIG. 23, the insulator 260 includes the core
main body coating portion 161 configured to cover the core main
body 111 of the armature core 108, and the tooth coating portion
162 configured to cover the teeth 112. The core main body coating
portion 161 and the tooth coating portion 162 are integrally formed
of an insulating material such as a resin or the like.
[0277] Here, in the fourth embodiment, the two partition walls 166
and 167 are integrally formed with the tooth coating portion end
surface 162a and the tooth coating portion side surface 162b of the
tooth coating portion 162 throughout the entire circumference.
However, in the fifth embodiment, only one partition wall 266 is
integrally formed with the tooth coating portion end surface 162a
and the tooth coating portion side surface 162b of the tooth
coating portion 162 throughout the entire circumference.
[0278] The partition wall 266 is formed in a plate shape, and
disposed slightly outside in the radial direction with respect to
substantially a center in the radial direction of the tooth coating
portion 162. In addition, flat chamfering portions 268 are formed
at corners of the partition wall 266.
[0279] As the partition walls 266 are formed at the tooth coating
portion end surface 162a and the tooth coating portion side surface
162b, a place at which the wire 114 of the tooth coating portion
162 is wound is divided into two chambers. Accordingly, two
accommodating portions 271 and 272 in which the two coils 291 and
292 are accommodated are formed at the tooth coating portion
162.
[0280] That is, the first accommodating portion 271 of the two
accommodating portions 271 and 272 is formed inside in the radial
direction of the partition wall 266 of the tooth coating portion
162. Then, the first coil 291 is accommodated in the first
accommodating portion 271. In addition, the second accommodating
portion 272 of the two accommodating portions 271 is formed outside
in the radial direction of the partition wall 266 of the tooth
coating portion 162. Then, the second coil 292 is accommodated in
the second accommodating portion 272.
[0281] In this way, the first coil 291 formed early in the sequence
is accommodated in the first accommodating portion 271 disposed
inside in the radial direction, and the second coil 292 formed late
in the sequence is accommodated in the second accommodating portion
272 disposed outside in the radial direction.
[0282] Here, since the flat chamfering portions 268 are formed at
the corners of the partition wall 266, when the coils 291 and 292
are accommodated in the accommodating portions 271 and 272, winding
workability of the wire 114 forming the coils 291 and 292 is
improved.
[0283] In addition, the winding collapse prevention plate 169 is
integrally formed with the connecting portion of the winding drum
coating portion end surface 164a of the tooth coating portion 162
and the main body coating portion end surface 161a of the core main
body coating portion 161. Further, the winding collapse prevention
convex portion 170 is integrally formed with the flange coating
portion end surface 164b of the tooth coating portion 162 at
substantially a center in the circumferential direction.
[0284] Here, the partition wall 266, the winding collapse
prevention plate 169 and the winding collapse prevention convex
portion 170 are formed to satisfy the following relation.
[0285] FIG. 24 is a view for describing relations between the
partition wall, the winding collapse prevention plate and the
winding collapse prevention convex portion.
[0286] That is, as shown in FIG. 24, when a height of the winding
collapse prevention plate 169 is set as T4 and a height of the
partition wall 266 is set as T5, the heights T4 and T5 satisfy the
following equation:
T4.ltoreq.T5 (4)
[0287] Further, when a distance between the winding collapse
prevention plate 169 and the partition wall 266 is set as L4 and a
distance between the partition wall 266 and the winding collapse
prevention convex portion 170 is set as L5, the distances L4 and L5
satisfy the following equation:
L4.gtoreq.L5 (5)
[0288] Then, when a capacity (see a portion hatched by solid lines)
of the first accommodating portion 271 formed by the winding
collapse prevention plate 169, the tooth coating portion 162 and
the partition wall 266 is set as Y4 and a capacity (see a portion
hatched by chain lines) of the second accommodating portion 272
formed by the partition wall 266, the tooth coating portion 162 and
the winding collapse prevention convex portion 170 is set as Y5,
the capacities Y4 and Y5 are set to satisfy the following
equation:
Y4.apprxeq.Y5 (6)
[0289] In order to satisfy equations (4) and (5), as the partition
wall 266 and the winding collapse prevention plate 169 are formed,
a wire height of the first coil 291 disposed inside in the radial
direction can be suppressed to a low level. In addition, as the
capacity Y4 of the first accommodating portion 271 and the capacity
Y5 of the second accommodating portion 272 satisfy equation (6),
lengths of the wires 114 forming the two coils 291 and 292 can be
uniformized.
[0290] Accordingly, according to the above-mentioned fifth
embodiment, even when the armature coil 209 is configured of the
two coils 291 and 292, the same effect as in the above-mentioned
fourth embodiment can be exhibited.
[0291] Further, in the above-mentioned fifth embodiment, the case
in which the winding collapse prevention plate 169 is integrally
formed with the connecting portion of the winding drum coating
portion end surface 164a of the tooth coating portion 162 and the
main body coating portion end surface 161a of the core main body
coating portion 161 has been described.
[0292] In addition, in the above-mentioned fifth embodiment, the
case in which the partition wall 266 is integrally formed with the
tooth coating portion end surface 162a and the tooth coating
portion side surface 162b throughout the entire circumference has
been described.
[0293] However, the present invention is not limited thereto but,
for example, may be configured as the following modified
examples.
First Modified Example
[0294] FIG. 25 is a perspective view of a state in which an
insulator is wound on an armature core according to a first
modified example of the fifth embodiment.
[0295] As shown in FIG. 25, the above-mentioned fifth embodiment
and the first modified example differ in that, in the insulator 260
of the above-mentioned fifth embodiment, while the winding collapse
prevention plate 169 is integrally formed with the connecting
portion of the winding drum coating portion end surface 164a of the
tooth coating portion 162 and the main body coating portion end
surface 161a of the core main body coating portion 161, in the
first modified example, the winding collapse prevention plate 169
is not integrally formed therewith.
[0296] Here, the first accommodating portion 171 partitioned by the
winding collapse prevention plate 169 is disposed at a root of the
tooth 112. For this reason, in the first coil 291 accommodated in
the first accommodating portion 171, collapse of the first coil 291
is suppressed by the first partition wall 166 and the main body
coating portion side surface 161b.
[0297] Accordingly, even when the first modified example is
configured as described above, the same effect as in the
above-mentioned fifth embodiment can be exhibited.
Second Modified Example
[0298] FIG. 26 is a perspective view of a state in which an
insulator is mounted on an armature core according to a second
modified example of the fifth embodiment.
[0299] As shown in FIG. 26, the above-mentioned fifth embodiment
and the second modified example differ in that, in the fifth
embodiment, while the partition wall 266 is integrally formed with
the tooth coating portion end surface 162a and the tooth coating
portion side surface 162b throughout the entire circumference, in
the second modified example, a partition wall 466 having a plate
shape is formed at only the tooth coating portion end surface
162a.
[0300] Even when the above-mentioned configuration is provided,
places at which the two coils 291 and 292 are disposed can be
divided. For this reason, the same effect as in the above-mentioned
fifth embodiment can be exhibited.
Third Modified Example
[0301] FIG. 27 is a perspective view of a state in which an
insulator is mounted on an armature core according to a third
modified example of the fifth embodiment.
[0302] As shown in FIG. 27, the second modified example and the
third modified example differ in that, in the above-mentioned
second modified example, while the winding collapse prevention
plate 169 is integrally formed with the connecting portion of the
winding drum coating portion end surface 164a of the tooth coating
portion 162 and the main body coating portion end surface 161a of
the core main body coating portion 161, in the third modified
example, the winding collapse prevention plate 169 is not
integrally formed therewith.
[0303] Even when the above-mentioned configuration is provided, the
same effect as in the second modified example of the
above-mentioned fifth embodiment can be obtained.
[0304] Further, the present invention is not limited to the
above-mentioned embodiments, and various modifications may be added
to the above-mentioned embodiments without departing from the
spirit of the present invention.
[0305] For example, the case in which the reduction motor 101 is
used for driving a wiper of an automobile has been described.
However, the present invention is not limited thereto but may be
used as driving sources of various equipment.
[0306] In addition, in the above-mentioned embodiments, the case in
which the electric motor 102 has the bottomed cylindrical yoke 105
and the armature 106 rotatably installed in the yoke 105 and the
wire 114 is wound on the armature core 108 has been described.
However, the present invention is not limited thereto but an
electric motor may be configured of a stator and a rotor rotatably
installed with respect the stator. According to the above-mentioned
configuration, the insulator is mounted on the stator core of the
stator, and the wire is wound from above the insulator. The
embodiment can be applied to the insulator used therein.
[0307] Further, the case in which the electric motor 102 of the
above-mentioned fourth embodiment is configured of the four-pole
six-slot eighteen-segment motor, and the electric motor 102 of the
fifth embodiment is configured of the four-pole six-slot
twelve-segment motor has been described.
[0308] However, the present invention is not limited thereto but
the insulator of the embodiment can be applied to various electric
motors having a structure in which the armature coil is formed of a
plurality of coils. In this case, it is preferable to vary the
number of partition walls according to the number of coils that
constitute the armature coil. For example, when the number of coils
that constitute the armature coil is 4, it is preferable to install
the three partition walls at the tooth coating portion 162 to form
four accommodating portions.
[0309] In addition, in the above-mentioned fourth embodiment, the
case in which the flat chamfering portions 168 are formed at the
corners of the partition walls 166 and 167 has been described.
Further, in the above-mentioned fifth embodiment, the case in which
the flat chamfering portion 268 is formed at the partition wall 266
has been described.
[0310] However, the present invention is not limited thereto but a
round chamfering portion may be formed instead of the flat
chamfering portion 168 or 268. Even when the round chamfering
portion is formed at each of the partition walls 166, 167 and 266,
a winding work of the wire 114 can be smoothly performed without
the wire 114 hooking on any of the partition walls 166, 167 and
266.
[0311] Further, in the above-mentioned embodiment, the case in
which each of the partition walls 166, 167, 366, 367, 266 and 466
is formed in a plate shape has been described. However, the present
invention is not limited thereto but each of the partition walls
166, 167, 366, 367, 266 and 466 may be formed such that each of the
coils 191, 192, 193, 291 and 292 can be disposed on the tooth
coating portion 162. For example, a plurality of protrusions or the
like may be formed at arbitrary positions instead of the partition
walls 166, 167, 366, 367, 266 and 466.
REFERENCE SIGNS LIST
[0312] 1 reduction motor [0313] 2 electric motor [0314] 3 rotation
shaft [0315] 5 yoke [0316] 7 permanent magnet (magnetic pole)
[0317] 8 armature core [0318] 9 armature coil (coil) [0319] 10
commutator [0320] 12 teeth [0321] 13 slot [0322] 14 wire (coil)
[0323] 15 segment [0324] 16 riser [0325] 17 connecting wire [0326]
21 brush [0327] 21a low speed brush [0328] 21b high speed brush
[0329] 21c common brush [0330] 91a, 91e U phase coil (coil of U
phase) [0331] 92a, 93a, 92e, 93e -U phase coil (coil of -U phase)
[0332] 91b, 92b, 91f, 92f -W phase coil (coil of -W phase) [0333]
93b, 93f W phase coil (coil of W phase) [0334] 91c, 91d V phase
coil (coil of V phase) [0335] 92c, 93c, 92d, 93d -V phase coil
(coil of -V phase) [0336] 9U1, 9U2 armature coil of U phase [0337]
9V1, 9V2 armature coil of V phase [0338] 9W1, 9W2 armature coil of
W phase
* * * * *