FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
[See section 10, Rule 13]
STATOR, MOTOR, COMPRESSOR, AND AIR CONDITIONER
MITSUBISHI ELECTRIC CORPORATION, A CORPORATION ORGANISED AND
EXISTING UNDER THE LAWS OF JAPAN, WHOSE ADDRESS IS 7-3,
MARUNOUCHI 2-CHOME, CHIYODA-KU, TOKYO 100-8310, JAPAN
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION
AND THE MANNER IN WHICH IT IS TO BE PERFORMED.
2
DESCRIPTION
TECHNICAL FIELD
5 [0001]
The present invention relates to a stator, a motor, a
compressor, and an air conditioner.
BACKGROUND ART
[0002]
10 In the technical field of motors, an increase in output and
reduction in size of motors are recently demanded. When the
output of the motor is increased, a current flowing through a
coil increases. Furthermore, when the size of the motor is
reduced, the current required to obtain the same output increases.
15 Thus, dissipation of heat generated in the coil is an issue to be
solved.
[0003]
In a motor used in a compressor, a coil of a stator is
hardly in contact with refrigerant and lubricating oil inside the
20 compressor. Thus, heat generated in the coil needs to be
dissipated from the stator core. Heat generation in the coil is
due to an electrical resistance of the coil, and thus it is
desirable that the electrical resistance of the coil is low in
order to suppress the heat generation in the coil.
25 [0004]
The use of an aluminum wire coil in combination with a
conventional copper wire coil is recently proposed in order to
reduce the cost and weight of a motor (see, for example, Patent
Reference 1).
30 PRIOR ART REFERENCE
PATENT REFERENCE
[0005]
[PATENT REFERENCE 1]
International Publication WO2014/188466 (see FIG. 3)
3
SUMMARY OF THE INVENTION
PROBLEM TO BE SOLVED BY THE INVENTION
[0006]
However, the aluminum wire coil has a higher electrical
resistivity than the copper wire coil, and 5 therefore a large
amount of heat is generated when a current flows through the
aluminum wire coil. Thus, it is demanded to enhance the heat
dissipation effect while using different types of coils.
[0007]
10 The present invention is intended to solve the abovedescribed
problems, and an object of the present invention is to
enhance the heat dissipation effect while using different types
of coils.
MEANS OF SOLVING THE PROBLEM
15 [0008]
A stator of the present invention includes a stator core
having an inner circumference extending in a circumferential
direction about an axis, and a slot formed on an outer side of
the inner circumference in a radial direction about the axis, and
20 a first coil and a second coil disposed in the slot and connected
in series with each other. The first coil has a conductor formed
of a first metal. The second coil has a conductor formed of a
second metal that has a lower electrical resistivity than that of
the first metal. The slot includes a slot opening opened to the
25 inner circumference of the stator core, a slot bottom portion
having a curved shape and disposed on an outer side of the slot
opening in the radial direction, and a first side portion and a
second side portion disposed between the slot opening and the
slot bottom portion and facing each other in the circumferential
30 direction. In a plane perpendicular to the axis, a first
straight line is defined as a straight line connecting a border
between the slot bottom portion and the first side portion and a
border between the slot bottom portion and the second side
portion. A first region is defined as a region surrounded by the
4
first straight line and the slot bottom portion. A second region
is defined as a region in the slot on an outer side of the slot
opening in the radial direction and on an inner side of the first
straight line in the radial direction. An area S1 of the first
region, a total cross-sectional area A1 of the 5 first coil in the
first region, an area S2 of the second region, and a total crosssectional
area A2 of the first coil in the second region satisfy
(A1/S1) > (A2/S2).
EFFECTS OF THE INVENTION
10 [0009]
According to the present invention, of the first and second
coils, the first coil which has the higher electrical resistivity
is densely disposed in the first region which is closer to the
outer circumference of the stator core than the second region.
15 Thus, the heat generated in the first coil can be efficiently
transferred to the stator core. Thus, the heat generated in the
first coil can be efficiently dissipated, and an increase in the
temperature of the first and second coils can be suppressed.
BRIEF DESCRIPTION OF THE DRAWINGS
20 [0010]
FIG. 1 is a cross-sectional view showing a motor of a first
embodiment.
FIGS. 2(A) and 2(B) are a cross-sectional view and a
perspective view showing a rotor of the first embodiment,
25 respectively.
FIG. 3 is an enlarged cross-sectional view showing a part
of a stator of the first embodiment.
FIG. 4 is a schematic diagram showing a connection state
between an aluminum wire coil and a copper wire coil of the first
30 embodiment.
FIG. 5 is a schematic diagram showing cross-sectional
structures of the aluminum wire coil and the copper wire coil of
the first embodiment.
FIG. 6 is an enlarged cross-sectional view showing a part
5
of the stator of the first embodiment.
FIG. 7 is a schematic diagram showing a heat dissipation
function from slots of the stator of the first embodiment.
FIG. 8 is an enlarged cross-sectional view showing a part
of a stator of a comparison 5 example.
FIG. 9 is a table showing characteristics of the aluminum
wire coil and the copper wire coil of the first embodiment.
FIG. 10 is a graph showing a cross-sectional area ratio and
a loss density ratio of the aluminum wire coil and the copper
10 wire coil.
FIG. 11 is an enlarged cross-sectional view showing a part
of a stator in a modification of the first embodiment.
FIG. 12 is a diagram showing a compressor to which the
motor of the first embodiment is applicable.
15 FIG. 13 is a diagram showing an air conditioner that
includes the compressor shown in FIG. 12.
MODE FOR CARRYING OUT THE INVENTION
[0011]
FIRST EMBODIMENT
20 FIG. 1 is a cross-sectional view showing a motor 100 of a
first embodiment. The motor 100 shown in FIG. 1 is an induction
motor and is used, for example, in a compressor of an air
conditioner. The motor 100 includes a stator 1 and a rotor 5
rotatably provided on an inner side of the stator 1. An air gap
25 is provided between the stator 1 and the rotor 5.
[0012]
Hereinafter, a direction of an axis C, which is a center of
rotation of the rotor 5, is referred to as an “axial direction”.
A circumferential direction (indicated by an arrow R1 in FIG. 1
30 and the like) about the axis C is referred to as a
“circumferential direction”. A radial direction about the axis C
is referred to as a “radial direction”.
[0013]
(Configuration of Rotor 5)
6
FIGS. 2(A) and 2(B) are a cross-sectional view and a
perspective view showing the rotor 5. As shown in FIG. 2(A), the
rotor 5 includes a rotor core 50 having a plurality of slots 51,
a shaft 55 which serves as a rotation shaft, and bars 60 inserted
into the slots 51 of 5 the rotor core 50.
[0014]
The rotor core 50 is obtained by stacking electromagnetic
steel sheets each having a thickness of, for example, 0.1 to 0.7
mm in the axial direction and integrating the sheets together by
10 crimping or the like. A circular shaft hole 54 is formed at a
center of the rotor core 50 in the radial direction. The shaft
55 is fixed to the shaft hole 54 by press-fitting. A center axis
of the shaft 55 is the axis C serving as the center of the
rotation of the rotor 5.
15 [0015]
The rotor core 50 is formed in an annular shape about the
axis C. The plurality of slots 51 (also referred to as rotor
slots) are formed at equal intervals in the circumferential
direction along an outer circumference 53 of the rotor core 50.
20 The number of slots 51 is 34 in this example, but is not limited
to 34. Each slot 51 is a groove extending in the radial
direction, and passes through the rotor core 50 in the axial
direction. Teeth 52 (also referred to as rotor teeth) are each
formed between two of the slots 51 adjacent to each other in the
25 circumferential direction.
[0016]
As shown in FIG. 2(B), the rotor 5 includes a pair of end
rings 61 and 62 on both ends of the rotor core 50 in the axial
direction. The end rings 61 and 62 are connected to both ends of
30 the bars 60 in the axial direction and integrally formed with the
bars 60. The bars 60 and the end rings 61 and 62 constitute a
squirrel-cage secondary conductor 6.
[0017]
The squirrel-cage secondary conductor 60 is formed of a
7
non-magnetic material with electrical conductivity such as, for
example, aluminum. The end rings 61 and 62 and the bars 60 of
the squirrel-cage secondary conductor 6 are formed by casting
aluminum at both ends of the rotor core 50 and in the slots 51.
Copper may be used in 5 place of aluminum.
[0018]
The bar 60 extends to be inclined so that one end of the
bar 60 in the longitudinal direction is displaced in the
circumferential direction with respect to the other end of the
10 bar 60. In FIG. 2(B), only one bar 60 is shown by a dashed line.
When magnetic flux of the stator 1 interlinks with the bars 60 of
the rotor 5, a secondary current is generated in the bars 60.
The secondary current and the magnetic flux of the stator 1
generates a torque that rotates the rotor 5.
15 [0019]
(Configuration of Stator 1)
FIG. 3 is an enlarged cross-sectional view showing a part
of the stator 1. The stator 1 includes a stator core 10 and a
coil 3 wound on the stator core 10. The coil 3 includes an
20 aluminum wire coil 31 as a first coil and a copper wire coil 32
as a second coil. The aluminum wire coil 31 and the copper wire
coil 32 will be described later.
[0020]
The stator core 10 is obtained by stacking electromagnetic
25 steel sheets each having a thickness of, for example, 0.1 to 0.7
mm in the axial direction, and integrating the sheets together by
crimping or the like. The stator core 10 has an inner
circumference 10b extending in the circumferential direction
about the axis C and an outer circumference 10a disposed on an
30 outer side of the inner circumference 10b in the radial direction.
In the stator core 10, the plurality of slots 13 opened to the
inner circumference 10b are formed at equal intervals in the
circumferential direction. The coil 3 is accommodated in the
slot 13. The number of slots 13 is 30 in this example, but is
8
not limited to 30.
[0021]
The stator core 10 includes an annular yoke (also referred
to as a core back) 11 and a plurality of teeth 12 protruding
inward in the radial direction from the yoke 5 11. The teeth 12
are arranged at equal intervals in the circumferential direction.
The above-described slot 13 is formed between two teeth 12
adjacent to each other in the circumferential direction. The
number of teeth 12 is the same as the number of slots 13 (in this
10 example, 30). The coil 3 is wound around the tooth 12.
[0022]
The tooth 12 has a tooth tip portion 12a at its tip end on
the inner side in the radial direction. The tooth tip portion
12a has a width (i.e., a dimension in the circumferential
15 direction) wider than the width of other portions of the tooth 12.
An end of the tooth tip portion 12a has an arc shape and forms
the above-described inner circumference 10b of the stator core 10.
[0023]
FIG. 4 is a diagram showing a connection state between the
20 aluminum wire coil 31 and the copper wire coil 32 of the coil 3.
The aluminum wire coil 31 and the copper wire coil 32 of the coil
3 are connected in series with each other. The coil 3 has threephase
(U-phase, V-phase, and W-phase) coil portions, and the coil
portions are connected in Y-connection.
25 [0024]
FIG. 5 is a schematic diagram showing cross-sectional
structures of the aluminum wire coil 31 and the copper wire coil
32. The aluminum wire coil 31 has a conductor 31a formed of
aluminum as a first metal, and a circumference of the conductor
30 31a is covered with an insulating resin film 31b. The first
metal forming the conductor 31a is aluminum in this example, but
is not limited to aluminum.
[0025]
An electrical resistance of the conductor 31a of the
9
aluminum wire coil 31 is expressed as RAl, and an electrical
resistivity of the conductor 31a is expressed as ρAl. A diameter
(also referred to as a wire diameter) of the aluminum wire coil
31 is expressed as DAl. A thickness of the film 31b is thinner as
compared with the diameter of the conductor 5 31a, and thus the
diameter DAl can be considered to be equivalent to the diameter of
the conductor 31a.
[0026]
The second coil 32 has a conductor 32a formed of copper as
10 a second metal that has a lower electrical resistivity than that
of the first metal. A circumference of the conductor 32a is
covered with an insulating coating 32b. The second metal forming
the conductor 32a is copper in this example, but is not limited
to copper.
15 [0027]
An electrical resistance of the conductor 32a of the copper
wire coil 32 is expressed as RCu, and an electrical resistivity
thereof is expressed as ρCu. A diameter of the copper wire coil
32 is expressed as DCu. Since a thickness of the coating 32b is
20 thinner as compared with the diameter of the conductor 32a, the
diameter DCu can be considered to be equivalent to the diameter of
the conductor 32a.
[0028]
FIG. 6 is an enlarged diagram showing a part of the stator
25 1 that includes the slot 13. The slot 13 has a slot opening 14
leading to the inner circumference 10b of the stator core 10 and
a slot bottom portion 13a having a curved shape and disposed on
an outer side of the slot opening 14 in the radial direction.
Further, the slot 13 has a first side portion 13b and a second
30 side portion 13c which are disposed between the slot opening 14
and the slot bottom portion 13a in the radial direction. The
first side portion 13b and the second side portion 13c face each
other in the circumferential direction.
[0029]
10
The slot opening 14 is formed between tooth tip portions
12a adjacent to each other in the circumferential direction. The
slot opening 14 serves as an inlet through which the coil 3
passes when the coil 3 is wound around the tooth 12, i.e., when
the coil 3 is disposed 5 in the slot 13.
[0030]
The slot bottom portion 13a has a curved shape (more
specifically, an arc shape) such that a center of the slot bottom
portion 13a in the circumferential direction protrudes outward in
10 the radial direction with respect to both ends of the slot bottom
portion 13a in the circumferential direction. The length of the
slot bottom portion 13a in the circumferential direction is
longer than the length of the slot opening 14 in the
circumferential direction.
15 [0031]
The side portions 13b and 13c extend from the slot opening
14 toward the slot bottom portion 13a. The side portions 13b and
13c extend such that an interval between these side portions in
the circumferential direction increases outward in the radial
20 direction.
[0032]
The first side portion 13b has a curved portion 131 at a
part leading to the slot opening 14. The curved portion 131 is
curved so that a part thereof located closer to the slot opening
25 14 is displaced inward in the circumferential direction in the
slot 13. The second side portion 13c has a curved portion 132 at
a part leading to the slot opening 14. The curved portion 132 is
curved so that a part thereof located closer to the slot opening
14 is displaced inward in the circumferential direction in the
30 slot 13.
[0033]
An insulating portion 2 is provided on an inner surface of
each slot 13. The insulating portion 2 is formed of, for example,
a resin such as polyethylene terephthalate (PET). The insulating
11
portion 2 electrically insulates the coil 3 in the slot 13 from
the stator core 10. The insulating portion 2 includes a first
part 21 covering the slot bottom portion 13a, a second part 22
covering the first side portion 13b, and a third part 23 covering
the second 5 side portion 13c.
[0034]
An interior of the slot 13 may be filled with a resin
having a high thermal conductivity so that the resin surrounds
the coil 3 (i.e., the aluminum wire coil 31 and the copper wire
10 coil 32). For example, polybutylene terephthalate (PBT) or the
like can be used as the resin.
[0035]
In this example, the interior of the slot 13 is divided
into a first region 101 and a second region 102. This will be
15 described below.
[0036]
In a plane perpendicular to the axis C, a first point P1 is
defined as a border between the slot bottom portion 13a of the
slot 13 and the first side portion 13b. A second point P2 is
20 defined as a border between the slot bottom portion 13a of the
slot 13 and the second side portion 13c. These points P1 and P2
correspond to both ends of the slot bottom portion 13a of the
slot 13 in the circumferential direction. A first straight line
L1 is defined as a straight line connecting the first point P1
25 and the second point P2. The first region 101 is defined as a
region surrounded by the first straight line L1 and the slot
bottom portion 13a.
[0037]
In the plane perpendicular to the axis C, a third point P3
30 is defined as a point disposed at an outer end of the slot
opening 14 in the radial direction and on the first side portion
13b side. A fourth point P4 is defined as a point disposed at
the outer end of the slot opening 14 in the radial direction and
on the second side portion 13c side. A second straight line L2
12
is defined as a straight line connecting the third point P3 and
the fourth point P4. The second region 102 is defined as a
region surrounded by the second straight line L2 and the first
straight line L1. In other words, the second region 102 is the
region on the outer side of the slot opening 5 14 in the radial
direction and on the inner side of the first straight line L1 in
the radial direction in the slot 13.
[0038]
Since the insulating portion 2 is provided on the inner
10 side of the slot 13, the points P1 to P4 may be defined on an
inner surface of the insulating portion 2. That is, the first
point P1 may be defined as a border between an inner surface of
the first part 21 and an inner surface of the second part 22 of
the insulating portion 2, while the second point P3 may be
15 defined as a border between the inner surface of the first part
21 and an inner surface of the third part 23 of the insulating
portion 2. The point P3 may be defined as a point closest to the
slot opening 14 on the inner surface of the second part 22 of the
insulating portion 2. The point P4 may be defined as a point
20 closest to the slot opening 14 on the inner surface of the third
part 23 of the insulating portion 2.
[0039]
An area of the first region 101 is expressed as S1, while
an area of the second region 102 is expressed as S2. A total
25 cross-sectional area of the aluminum wire coil 31 disposed in the
first region 101 is expressed as A1, while a total crosssectional
area of the aluminum wire coil 31 disposed in the
second region 102 is expressed as A2. A total cross-sectional
area of the copper wire coil 32 disposed in the first region 101
30 is expressed as C1, while a total cross-sectional area of the
copper wire coil 32 disposed in the second region 102 is
expressed as C2.
[0040]
In this regard, the “total cross-sectional area of the coil”
13
means a sum of cross-sectional areas of coil elements disposed in
a given region. In other words, the “total cross-sectional area
of the coil” means a product of a cross-sectional area of each
coil element of the coil and the number of the coil elements
disposed in 5 the given region.
[0041]
The area S1 of the first region 101, the total crosssectional
area A1 of the aluminum wire coil 31 in the first
region 101, the area S2 of the second region 102, and the total
10 cross-sectional area A2 of the aluminum wire coil 31 in the
second region 102 satisfy (A1/S1) > (A2/S2).
[0042]
That is, the aluminum wire coil 31 is arranged so that an
occupancy density thereof in the first region 101 is higher than
15 an occupancy density thereof in the second region 102. In other
words, the aluminum wire coil 31 is disposed more densely in the
first region 101 than in the second region 102.
[0043]
The area S1 of the first region 101, the total cross20
sectional area A1 of the aluminum wire coil 31 in the first
region 101, and the total cross-sectional area C1 of the copper
wire coil 32 in the first region 101 satisfy (A1/S1) > (C1/S1).
[0044]
That is, in the first region 101, the occupancy density of
25 the aluminum wire coil 31 is higher than the occupancy density of
the copper wire coil 32. In other words, in the first region 101,
the aluminum wire coil 31 is disposed more densely than the
copper wire coil 32.
[0045]
30 The total cross-sectional area A1 of the aluminum wire coil
31 and the total cross-sectional area C1 of the copper wire coil
32 in the first region, and the total cross-sectional area A2 of
the aluminum wire coil 31 and the total cross-sectional area C2
of the copper wire coil 32 in the second region 102 satisfy
14
(A1/C1) > (A2/C2). That is, a ratio of the total cross-sectional
area of the aluminum wire coil 31 to the total cross-sectional
area of the copper wire coil 32 is higher in the first region 101
than in the second region 102.
5 [0046]
(Function)
Next, a function of the motor in the first
embodiment will be described. When the output of the motor 100
increases, a current flowing through the coil 3 increases, and
10 thus the amount of heat generated in the coil 3 increases. An
area where the coil 3 disposed in the slot 13 is in contact with
the refrigerant, the lubricating oil, and the air is small, and
thus heat of the coil 3 is dissipated through the stator core 10.
In order to suppress an increase in the temperature of the coil 3,
15 it is necessary to effectively dissipate the heat of the coil 3
through the stator core 10.
[0047]
FIG. 7 is a schematic diagram showing a heat dissipation
function from the slots 13 in the stator 1. As shown in FIG. 7,
20 the heat generated in the coil 3 in the slot 13 of the stator 1
is dissipated through a heat dissipation path from the slot 13
toward the yoke 11 on the outer side of the slot 13 in the radial
direction as indicated by the arrow H1, or through heat
dissipation paths from the slot 13 toward the teeth 12 on both
25 sides of the slot 13 in the circumferential direction as
indicated by the arrow H2.
[0048]
Among the heat dissipation paths, the tooth 12 has a small
area, and heat is transferred to one tooth 12 from the slots 13
30 on both sides of the tooth 12. Thus, the heat tends to be
accumulated in the tooth 12. In contrast, the yoke 11 has a
large area and its outer circumference 10a (FIG. 1) is in contact
with a closed container (to be described later) of the compressor
or the like, so that the heat is easily dissipated to the outside
15
of the stator 1. That is, in the slot 13, the heat dissipation
efficiency is higher in the first region 101 adjacent to the yoke
11 than in the second region 102 adjacent to the tooth 12.
[0049]
The electrical resistivity of the aluminum 5 wire coil 31 is
higher than that of the copper wire coil 32, and thus the amount
of heat generated in the aluminum wire coil 31 is larger than the
amount of heat generated in the copper wire coil 32. Further,
the thermal conductivity of the aluminum wire coil 31 is lower
10 than that of the copper wire coil 32, and therefore the
temperature of the aluminum wire coil 31 is easily raised.
[0050]
Thus, in the first embodiment, the aluminum wire coil 31 is
disposed more densely in the first region 101 than in the second
15 region 102. That is, (A1/S1) > (A2/S2) is satisfied. The
aluminum wire coil 31, whose temperature is easily raised, is
disposed more densely in the first region 101 than in the second
region 102, and therefore the heat of the aluminum wire coil 31
can be efficiently dissipated through the yoke 11.
20 [0051]
In addition, since the contact area between coil elements
of the aluminum wire coil 31 and the contact area between the
aluminum wire coil 31 and the copper wire coil 32 increase, and
the distance between the aluminum wire coil 31 and the stator
25 core 10 is shortened, the heat of the aluminum wire coil 31 is
easily transferred to the stator core 10. Thus, an increase in
the temperature of the aluminum wire coil 31 can be suppressed.
[0052]
In the first region 101, the occupancy density of the
30 aluminum wire coil 31 is higher than the occupancy density of the
copper wire coil 32. That is, (A1/S1) > (C1/S1) is satisfied.
In the first region 101, the aluminum wire coil 31 is disposed
more densely than the copper wire coil 32, and thus the heat of
the aluminum wire coil 31 can be easily dissipated through the
16
yoke 11. Thus, the heat dissipation effect can be further
enhanced.
[0053]
The ratio of the total cross-sectional area of the aluminum
wire coil 31 to the total cross-sectional area 5 of the copper wire
coil 32 is higher in the first region 101 than in the second
region 102. That is, (A1/C1) > (A2/C2) is satisfied. Since the
ratio of the total cross-sectional area of the aluminum wire coil
31 to that of the copper wire coil 32 is higher in the first
10 region 101, the heat of the aluminum wire coil 31 can be easily
dissipated through the yoke 11. Thus, the heat dissipation
effect can be further enhanced.
[0054]
FIG. 8 is an enlarged diagram showing a part of a stator
15 201 of a comparison example. A stator core 210 of the stator 201
of the comparison example includes an annular yoke 211 and a
plurality of teeth 212 extending inward in the radial direction
from the yoke 211. Slots 213 are each formed between adjacent
two of the teeth 212. An insulating portion 202 is formed on an
20 inner surface of each slot 213.
[0055]
An aluminum wire coil 231 and a copper wire coil 232 are
disposed in the slot 213. Unlike the coils 31 and 32 of the
first embodiment, the aluminum wire coil 231 is disposed on one
25 side of the slot 213 in the circumferential direction (on the
right side in FIG. 8), while the copper wire coil 232 is disposed
on the other side of the slot 213 in the circumferential
direction (on the left side in FIG. 8).
[0056]
30 Thus, in the stator 201 of the comparison example, most of
the heat from the aluminum wire coil 231 is dissipated through
the teeth 212. Since the heat dissipation efficiency of the
teeth 212 is low as compared to that of the yoke 211 as described
above, the effect of suppressing an increase in the temperature
17
of the aluminum wire coil 231 is not high.
[0057]
In contrast, in the first embodiment, as shown in FIGS. 6
and 7, the aluminum wire coil 31, which has a high electrical
resistivity and whose temperature is raised easily, 5 is disposed
more densely in the first region 101 than in the second region
102. Thus, the heat generated in the aluminum wire coil 31 is
efficiently dissipated to the outside through the yoke 11, and
thus the high heat dissipation effect can be obtained.
10 [0058]
(Diameter of Each Coil)
Next, a relationship between the diameters of the coils 31
and 32 will be described. Since the aluminum wire coil 31 and
the copper wire coil 32 are connected in series with each other,
15 the currents flowing through both coils 31 and 32 are equal.
Therefore, a loss generated in the aluminum wire coil 31 having
the higher electrical resistivity is higher than a loss generated
in the copper wire coil 32. Thus, it is desirable to concentrate
as many coil elements of the aluminum wire coil 31 as possible in
20 the first region 101 where the heat dissipation efficiency is
high.
[0059]
As described above, the electrical resistivity of the
aluminum wire coil 31 is expressed as ρAl [Ω•m], and the diameter
25 of the aluminum wire coil 31 is expressed as DAl [mm]. The
electrical resistivity of the copper wire coil 32 is expressed as
ρCu [Ω•m], and the diameter of the copper wire coil 32 is
expressed as DCu [mm]. An electrical resistance of a coil is a
value (i.e., ρ × L/S) obtained by multiplying an electrical
30 resistivity ρ by a length L of the coil and dividing the
multiplied value by a cross-sectional area S of the coil. That
is, when the length L of the coil is constant, the electrical
resistance of the coil increases as the electrical resistivity of
the coil increases, and the electrical resistance of the coil
18
decreases as the cross-sectional area of the coil decreases.
[0060]
A wire cross-sectional area of the aluminum wire coil 31 is
expressed as SAl, while a wire cross-sectional area of the copper
wire coil 32 is expressed as SCu. In the case 5 where the aluminum
wire coil 31 and the copper wire coil 32 have the equal length L
and the current flowing through the coils 31 and 32 is 1 [A], a
loss [W] generated in the aluminum wire coil 31, i.e., the
product of the square of the current and the electrical
10 resistance is expressed as ρAl × (L/SAl), while a loss [W]
generated in the copper wire coil 32 is expressed as ρCu × (L/SCu).
[0061]
When the loss generated in the aluminum wire coil 31 is
equal to the loss generated in the copper wire coil 32, ρAl ×
15 (L/SAl) = ρCu × (L/SCu) is satisfied. When this equation is solved
for SAl, SAl = (ρAl/ρCu) × SCu is obtained. That is, the crosssectional
area SAl of the aluminum wire coil 31 is (ρAl/ρCu) times
as large as the cross-sectional area SCu of the copper wire coil
32.
20 [0062]
The cross-sectional area of a coil is proportional to the
square of the diameter of the coil. Thus, when the loss
generated in the aluminum wire coil 31 is equal to the loss
generated in the copper wire coil 32, the diameter DAl [mm] of the
25 aluminum wire coil 31 is √(ρAl/ρCu) times the diameter DCu [mm] of
the copper wire coil 32.
[0063]
Thus, in order to make the loss generated in the aluminum
wire coil 31 equal to or more than the loss generated in the
30 copper wire coil 32, it is sufficient that the diameter DAl of the
aluminum wire coil 31 is √(ρAl/ρCu) times or less the diameter DCu
[mm] of the copper wire coil 32. In other words, it is
sufficient that the diameter DAl of the aluminum wire coil 31 is
less than or equal to √(ρAl/ρCu) × DCu.
19
[0064]
For this reason, it is most desirable that the electrical
resistivity ρAl [W/m] and the diameter DAl of the aluminum wire
coil 31 and the electrical resistivity ρCu [W/m] and the diameter
DCu [mm] of the copper wire coil 32 satisfy the 5 following equation
(1).
D���� ≤ D���� < ��
������
������
× D���� ••• (1)
[0065]
When the diameter DAl of the aluminum wire coil 31 is less
10 than or equal to √(ρAl/ρCu) × DCu, the electrical resistance of the
aluminum wire coil 31 is less than or equal to the electrical
resistance of the copper wire coil 32, and therefore the loss
generated in the aluminum wire coil 31 is greater than or equal
to the loss generated in the copper wire coil 32. That is, a
15 large loss (i.e., heat) is generated in the aluminum wire coil 31
concentrated in the first region 101, and its heat is dissipated
through the yoke 11 of the stator core 10. Thus, especially high
heat dissipation effect can be obtained.
[0066]
20 For example, when the electrical resistivity ρAl of the
aluminum wire coil 31 is 2.82 × 10-8 [Ω•m] and the electrical
resistivity ρCu of the copper wire coil 32 is 1.68 × 10-8 [Ω•m],
the upper limit of the diameter DAl [mm] of the aluminum wire coil
31 is 1.296 times the diameter DCu [mm] of the copper wire coil 32.
25 When the diameter DAl of the aluminum wire coil 31 is smaller than
1.296 × DCu, especially high heat dissipation effect is obtained.
[0067]
In the equation (1), the lower limit of the diameter DAl of
the aluminum wire coil 31 is equal to the diameter DCu of the
30 copper wire coil 32. This is because, as mechanical strength of
the aluminum wire coil 31 per unit cross-sectional area is lower
than that of the copper wire coil 32, the diameter DAl of the
aluminum wire coil 31 is desirably greater than or equal to the
20
diameter DCu of the copper wire coil 32 (i.e., DCu ≤ DAl) in order
to obtain sufficient strength of the aluminum wire coil 31 in a
winding process.
[0068]
When the electrical resistivity ρAl and the 5 diameter DAl of
the aluminum wire coil 31 and the electrical resistivity ρCu and
the diameter DCu of the copper wire coil 32 satisfy the equation
(1), a large loss is generated in the aluminum wire coil 31
concentrated in the first region 101, and its heat can be
10 efficiently dissipated through the yoke 11. Further, sufficient
strength of the aluminum wire coil 31 in the winding process can
be obtained.
[0069]
Although the current flowing through the coils 31 and 32 is
15 assumed to be 1 [A] when the equation (1) is derived, the current
is not limited to 1 [A]. This is because of the following reason.
If a current flowing through the coils 31 and 32 is expressed as
I [A], and the loss generated in the aluminum wire coil 31 is
equal to the loss generated in the copper wire coil 32, ρAl ×
20 (L/SAl) × I2 = ρCu × (L/SCu) × I2 is satisfied. From this equation,
the above-described SAl = (ρAl/ρCu) × SCu is obtained, from which
the equation (1) is derived.
[0070]
The relationship between the electrical resistivity ρAl and
25 the diameter DAl of the aluminum wire coil 31 and the electrical
resistivity ρCu and the diameter DCu of the copper wire coil 32 is
not limited to the above-described equation (1). The following
equation (2) may be satisfied.
0.5 × D���� ≤ D���� < ��
������
������
× D���� ••• (2)
30 [0071]
The upper limit of the diameter DAl of the aluminum wire
coil 31 in equation (2) is the same as that in equation (1). The
reason for this is as described above. In contrast, the lower
21
limit of the diameter DAl of the aluminum wire coil 31 in equation
(2) is 0.5 × DCu, i.e., 1/2 of the diameter DCu of the coil 32.
[0072]
In a process of winding the coil 3 composed of the aluminum
wire coil 31 and the copper wire coil 32 connected 5 in series
around the tooth 12 of the stator core 10, it is desirable to use
a common winding machine in order to avoid complicating the
process. When the aluminum wire coil 31 and the copper wire coil
32 have different diameters, it is necessary to adjust a nozzle
10 diameter of a winding nozzle of the winding machine to the
diameter of the thicker coil.
[0073]
If the diameter DAl of the aluminum wire coil 31 is less
than 1/2 of the diameter DCu of the copper wire coil 32, the
15 aluminum wire coil 31 may be inserted in two rows into the
winding nozzle and may be damaged thereby. The winding machine
winds the aluminum wire coil 31 and the copper wire coil 32 by
applying the same tension, and thus disconnection of the aluminum
wire coil 31 may occur if the aluminum wire coil 31 is extremely
20 thin.
[0074]
For the reasons described above, in equation (2), the
diameter DAl [mm] of the aluminum wire coil 31 is set to be
greater than or equal to 0.5 × DCu [mm]. Thus, a large loss is
25 generated in the aluminum wire coil 31 concentrated in the first
region 101, and its heat is effectively dissipated through the
yoke 11, while the damage and disconnection of the aluminum wire
coil 31 in the winding process can be prevented.
[0075]
30 (Cross-sectional Area Ratio of Coils)
The ratio of the wire cross-sectional area SAl of the
aluminum wire coil 31 to the wire cross-sectional area SCu of the
copper wire coil 32, i.e., SAl/SCu is referred to as a crosssectional
area ratio k. Since the cross-sectional area SAl is  ×
22
(DAl/2)2 and the cross-sectional area SCu is  × (DCu/2)2, the
cross-sectional area ratio k can be expressed as k = (DAl/DCu)2.
When the cross-sectional area ratio k is used, DCu ≤ DAl of
equation (1) is expressed as 1 ≤ k. Further, 0.5 × DCu ≤ DAl of
equation (2) is expressed 5 as k ≤ 0.25.
[0076]
As described above, the aluminum wire coil 31 and the
copper wire coil 32 are connected in series, and the loss
generated in the aluminum wire coil 31 with the higher electrical
10 resistivity is higher than the loss generated in the copper wire
coil 32. In the first region 101 of the slot 13, the aluminum
wire coil 31 in which a large loss is generated is disposed more
densely, and thus the heat of the aluminum wire coil 31 is
dissipated through the yoke 11.
15 [0077]
A loss density will be described herein. The loss density
[W/mm2] is a value obtained by dividing the loss generated in the
coil by the wire cross-sectional area of the coil. Here,
consideration will be given to a range of the loss density of the
20 aluminum wire coil 31 with respect to the loss density of the
copper wire coil 32 with which the heat dissipation effect is
enhanced.
[0078]
The wire cross-sectional area SAl [mm2] of the aluminum wire
25 coil 31 and the wire cross-sectional area SCu [mm2] of the copper
wire coil 32 have the relationship of SAl = k × SCu using the
definition (k = SAl/SCu) of the cross-sectional area ratio k.
When the current flowing through the coil 3 is 1 [A], the loss
[W] generated in the aluminum wire coil 31 is RAl, while the loss
30 [W] generated in the copper wire coil 32 is RCu.
[0079]
Therefore, the loss density [W/m2] of the aluminum wire
coil 31 is RAl/SAl, and is expressed as RAl/(k × SCu) using the
cross-sectional area ratio k. The loss density [W/m2] of the
23
copper wire coil 32 is RCu/SCu.
[0080]
A loss density ratio is defined as a ratio of the loss
density of the aluminum wire coil 31 to the loss density of the
copper wire coil 32. The loss density 5 ratio is {RAl/(k ×
SCu)}/{RCu/SCu}, and thus is expressed as RAl/(k × RCu).
[0081]
FIG. 9 is a table showing a cross-sectional area S [mm2], a
cross-sectional area ratio k, an electrical resistance [Ω/km], a
10 current [A], a loss [W], a loss density [W/mm2], and a loss
density ratio of each of the aluminum wire coil 31 and the copper
wire coil 32.
[0082]
When the loss density ratio is 1 or more, that is, when the
15 loss density of the aluminum wire coil 31 is greater than or
equal to the loss density of the copper wire coil 32, a large
loss can be generated in the aluminum wire coil 31 disposed in
the first region 101, and the heat can be efficiently dissipated
through the yoke 11. Thus, 1 ≤ RAl/(k × RCu) is desirable.
20 [0083]
As the mechanical strength of the aluminum wire coil 31 per
unit cross-sectional area is lower than that of the copper wire
coil 32, it is desirable that the diameter DAl of the aluminum
wire coil 31 is greater than or equal to the diameter DCu of the
25 copper wire coil 32, in order to obtain sufficient strength for
the winding process using the common winding machine. Thus, 1 ≤
k is desirable.
[0084]
From the above, the cross-sectional area ratio k, the
30 electrical resistance RAl [Ω] of the aluminum wire coil 31, and
the electrical resistance RCu [Ω] of the copper wire coil 32
satisfy the following equations (3) and (4). Thus, a large loss
can be generated in the aluminum wire coil 31 concentrated in the
first region 101 and its heat can be efficiently dissipated
24
through the yoke 11, while the sufficient strength of the
aluminum wire coil 31 in the winding process can be obtained.
[0085]
1 ≤
������
�� × ������
••• (3)
5 1 ≤ k ••• (4)
[0086]
Here, the upper limit of the loss density ratio RAl/(k ×
RCu) is RAl/RCu which is obtained by substituting 1 into k. For
example, when the diameter DCu of the copper wire coil 32 is 0.9
10 [mm], the electrical resistance RCu of the copper wire coil 32 is
27.1 [Ω], the diameter DAl of the aluminum wire coil 31 is 0.9
[mm], and the electrical resistance RAl of the aluminum wire coil
31 is 73.72 [Ω], the upper limit of RAl/(k × RCu) is RAl/RCu = 1.679.
Thus, a desirable range of the loss density ratio RAl/(k × RCu) is
15 expressed as 1 ≤ RAl/(k × RCu) ≤ 1.679.
[0087]
FIG. 10 is a graph showing the relationship between the
cross-sectional area ratio k and the loss density ratio when the
diameter DCu of the copper wire coil 32 is set to 0.9 [mm] and the
20 diameter DAl of the aluminum wire coil 31 is changed. As shown in
FIG. 10, a desirable range of the loss density ratio when the
diameter DCu of the copper wire coil 32 is 0.9 [mm] is 1 ≤ RAl/(k
× RCu) ≤ 1.679.
[0088]
25 In addition, the cross-sectional area ratio k, the
electrical resistance RAl[Ω] of the aluminum wire coil 31, and the
electrical resistance RCu[Ω] of the copper wire coil 32 may
satisfy the following equations (5) and (6). Equation (5) is the
same as the equation (3) described above.
1 ≤
������
�� × ������
30 ••• (5)
0.25 ≤ k ••• (6)
[0089]
25
As described above, when the aluminum wire coil 31 and the
copper wire coil 32 are wound using the common winding machine,
the nozzle diameter of the winding nozzle of the winding machine
needs to be adjusted to the diameter of the thicker coil. If the
diameter DAl of the aluminum wire coil 31 is less 5 than or equal to
1/2 of the diameter DCu of the copper wire coil 32, the aluminum
wire coil 31 may be inserted in two rows into the winding nozzle
and may be damaged thereby. The winding machine winds the
aluminum wire coil 31 and the copper wire coil 32 by applying the
10 same tension, and thus disconnection of the aluminum wire coil 31
may occur if the aluminum wire coil 31 is extremely thin.
[0090]
Thus, the lower limit of diameter DAl [mm] of the aluminum
wire coil 31 is desirably 0.5 × DCu [mm]. This condition is
15 expressed as 0.25 ≤ k using the cross-sectional area ratio k.
[0091]
As described above, the cross-sectional area ratio k, the
electrical resistance RAl[Ω] of the aluminum wire coil 31, and the
electrical resistance RCu [Ω] of the copper wire coil 32 satisfy
20 equations (5) and (6). Thus, a large loss can be generated in
the aluminum wire coil 31 concentrated in the first region 101 of
the slot 13 and its heat can be efficiently dissipated through
the yoke 11, while the damage and disconnection of the aluminum
wire coil 31 in the winding process can be sufficiently prevented.
25 [0092]
Here, the upper limit of loss density ratio RAl/(k × RCu) is
RAl/(0.25 × RCu) which is obtained by substituting 0.25 into k.
For example, when the diameter DCu of the copper wire coil 32 is
0.9 [mm], the electrical resistance RCu of the copper wire coil 32
30 is 27.1 [Ω], the diameter DAl of the aluminum wire coil 31 is 0.45
[mm], and the electrical resistance RAl of the aluminum wire coil
31 is 174.9 [Ω], the upper limit of RAl/(k × RCu) is RAl/(0.25 ×
RCu) = 25.815. In this case, a desirable range of the loss
density ratio RAl/(k × RCu) is expressed as 1 ≤ RAl(k × RCu) ≤
26
25.815.
[0093]
(Induction Motor)
The motor 100 of the first embodiment is an induction motor
as described above. That is, a rotating 5 magnetic field is
generated by the current in the coil 3 of the stator 1, and
generates an induced current in the squirrel-cage secondary
conductor 6 of the rotor 5, so that torque is produced by the
action of the induced current and the rotating magnetic field.
10 [0094]
The induction motor is generally driven without using an
inverter. That is, a controller of the motor 100 generally
drives the motor 100 by supplying a constant voltage to the coil
3. Thus, the fluctuation in load applied to the motor 100 or
15 voltage supplied to the motor 100 may cause significant increase
in the current flowing through the coil 3, and may cause rise in
temperature of the coil 3.
[0095]
Since the motor 100 of the first embodiment has the high
20 heat dissipation effect as described above and thus can suppress
the increase in the temperature of the coil 3, especially high
effect can be obtained when the motor 100 is applied to the
induction motor where the current largely fluctuates. Although
the motor 100 of the first embodiment is the induction motor, the
25 high heat dissipation effect can be obtained even when the motor
100 is a synchronous motor.
[0096]
(Effects of First Embodiment)
As described above, in the first embodiment of the present
30 invention, the area S1 of the first region 101 of the slot 13,
the total cross-sectional area A1 of the aluminum wire coil 31
(i.e., the first coil) in the first region 101, the area S2 of
the second region 102, and the total cross-sectional area A2 of
the aluminum wire coil 31 in the second region 102 satisfy
27
(A1/S1) > (A2/S2). In this way, the aluminum wire coil 31 with
the higher electrical resistivity are densely disposed in the
first region 101 on the outer side of the slot 13 in the radial
direction, and thus the heat of the aluminum wire coil 31 can be
efficiently dissipated through the yoke 11 of the 5 stator core 10,
and thus an increase in the temperature can be suppressed.
Furthermore, the heat dissipation effect of the motor 100 makes
it possible to flow a large amount of current through the coil 3,
and thus an output of the motor 100 can be increased.
10 [0097]
The total cross-sectional area A1 of the aluminum wire coil
31 in the first region 101, the total cross-sectional area C1 of
the copper wire coil 32 (i.e., the second coil) in the first
region 101, and the area S1 of the first region 101 satisfy
15 (A1/S1) > (C1/S1). In this way, the occupancy density of the
aluminum wire coil 31 is higher than the occupancy density of the
copper wire coil 32 in the first region 101, and thus the heat of
the aluminum wire coil 31 can be efficiently dissipated through
the yoke 11 of the stator core 10. Therefore, the heat
20 dissipation effect can be further enhanced.
[0098]
The total cross-sectional area A1 of the aluminum wire coil
31 in the first region 101, the total cross-sectional area C1 of
the copper wire coil 32 in the first region 101, the total cross25
sectional area A2 of the aluminum wire coil 31 in the second
region 102, and the total cross-sectional area C2 of the copper
wire coil 32 in the first region 101 satisfy (A1/C1) > (A2/C2).
In this way, the ratio of the total cross-sectional area of the
aluminum wire coil 31 to that of the copper wire coil 32 is
30 higher in the first region 101 than in the second region 102, and
thus the heat of the aluminum wire coil 31 can be efficiently
dissipated through the yoke 11 of the stator core 10, so that the
heat dissipation effect can be further enhanced.
[0099]
28
The electrical resistivity ρAl [Ω•m] and the diameter DAl
[mm] of the aluminum wire coil 31 and the electrical resistivity
ρCu [Ω•m] and the diameter DCu [mm] of the copper wire coil 32
satisfy the above-described equation (1). Thus, a large loss
(i.e., heat) is generated in the aluminum 5 wire coil 31
concentrated in the first region 101, and its heat is dissipated
through the yoke 11 of the stator core 10, so that the heat
dissipation effect can be further enhanced. Moreover, by making
the diameter DAl of the aluminum wire coil 31 greater than or
10 equal to the diameter DCu of the copper wire coil 32, sufficient
strength of the aluminum wire coil 31 in the winding process can
be obtained.
[0100]
The electrical resistivity ρAl [Ω•m] and the diameter DAl
15 [mm] of the aluminum wire coil 31 and the electrical resistivity
ρCu [Ω•m] and the diameter DCu [mm] of the copper wire coil 32
satisfy the above-described equation (2), and thus the heat
dissipation effect can be enhanced. Further, by making the
diameter DAl of the aluminum wire coil 31 greater than or equal to
20 1/2 of the diameter DCu of the copper wire coil 32, the damage and
disconnection of the aluminum wire coil 31 in the winding process
can be prevented.
[0101]
In addition, the electrical resistance RAl of the aluminum
25 wire coil 31, the electrical resistance RCu of the copper wire
coil 32, and the cross-sectional area ratio k, which is the ratio
of the cross-sectional area of the aluminum wire coil 31 to the
cross-sectional area of the copper wire coil 32, satisfy the
above-described equation (3). Thus, the loss density of the
30 aluminum wire coil 31 is greater than or equal to the loss
density of the copper wire coil 32. Therefore, a large loss can
be generated in the aluminum wire coil 31, and its heat can be
efficiently dissipated through the yoke 11, so that the heat
dissipation effect can be further enhanced.
29
[0102]
When the cross-sectional area ratio k is greater than or
equal to 1, sufficient strength of the aluminum wire coil 31 can
be obtained in the winding process using the common winding
machine. When the cross-sectional area ratio 5 k is greater than
or equal to 0.25, the damage or disconnection of the aluminum
wire coil 31 can be prevented in the winding process using the
common winding machine.
[0103]
10 The motor 100 of the first embodiment exhibits especially
high effect when the motor 100 is applied to the induction motor
which is generally driven without using the inverter.
[0104]
Although the aluminum wire coil 31 as the first coil and
15 the copper wire coil 32 as the second coil are used in the first
embodiment, the coils are not limited to a combination of the
aluminum wire coil 31 and the copper wire coil 32. For example,
two types of coils may be selected from coils made of gold,
silver, copper, aluminum, and the like. In this case, one of the
20 selected coils that has a higher electrical resistivity may be
used as the first coil, while the other of the selected coils
that has a lower electrical resistivity may be used as the second
coil.
[0105]
25 Modification
FIG. 11 is an enlarged diagram showing a part including the
slot 13 of a stator in a modification of the first embodiment.
In the first embodiment described above, the aluminum wire coil
31 and the copper wire coil 32 are disposed in the first region
30 101 of the slot 13, and the occupancy density of the aluminum
wire coil 31 is higher than the occupancy density of the copper
wire coil 32 in the first region 101.
[0106]
In contrast, in the modification, only the aluminum wire
30
coil 31 is disposed in the first region 101 of the slot 13. In
the second region 102, the aluminum wire coil 31 and the copper
wire coil 32 are disposed. The other configuration of the
modification is the same as described in the first embodiment.
5 [0107]
In the modification, only the aluminum wire coil 31 is
disposed in the first region 101 where the heat dissipation
efficiency is high. Thus, the heat of the aluminum wire coil 31
can be more effectively transferred to the stator core 10 and
10 dissipated therethrough.
[0108]
(Scroll Compressor)
Next, a scroll compressor 300 as the compressor to which
the motor 100 described in the first embodiment and the
15 modification is applicable will be described. FIG. 12 is a
sectional view showing the scroll compressor 300. The scroll
compressor 300 includes a closed container 307, a compression
mechanism 305 disposed in the closed container 307, the motor 100
for driving the compression mechanism 305, the shaft 55
20 connecting the compression mechanism 305 and the motor 100, and a
sub-frame 308 supporting a lower end of the shaft 55 (i.e., an
end of the shaft opposite to the compression mechanism 305).
[0109]
The compression mechanism 305 includes a fixed scroll 301
25 having a spiral portion, an swing scroll 302 having a spiral
portion that forms a compression chamber between itself and the
spiral portion of the fixed scroll 301, a compliance frame 303
that holds an upper end of the shaft 55, and a guide frame 304
that is fixed to the closed container 307 and holds the
30 compliance frame 303.
[0110]
A suction pipe 310 penetrating the closed container 307 is
press-fitted into the fixed scroll 301. The closed container 307
is provided with a discharge pipe 311 that allows high-pressure
31
refrigerant gas discharged from the fixed scroll 301 to be
discharged to the outside. The discharge pipe 311 is connected
to a not shown opening provided between the motor 100 and the
compression mechanism 305 in the closed container 307.
5 [0111]
The motor 100 is fixed to the closed container 307 by
fitting the stator 1 into the closed container 307. The
configuration of the motor 100 is as described above. A glass
terminal 309 for supplying electric power to the motor 100 is
10 fixed to the closed container 307 by welding.
[0112]
When the motor 100 rotates, the rotation of the motor 100
is transmitted to the swing scroll 302, and the swing scroll 302
swings. When the swing scroll 302 swings, a volume of the
15 compression chamber formed between the spiral portion of the
swing scroll 302 and the spiral portion of the fixed scroll 301
changes. Refrigerant gas is sucked therein through the suction
pipe 310, compressed, and discharged through the discharged pipe
311.
20 [0113]
During rotation of the motor 100, the current flows through
the coil 3, and heat is generated. The heat generated in the
coil 3 is transferred to the stator core 10 via the insulating
portion 2 (FIG. 1) and then dissipated from the stator core 10 to
25 the closed container 307. The motor 100 of each of the first
embodiment and the modification has the high heat dissipation
effect and thus can suppress an increase in the temperature
inside the scroll compressor 300. With the increase in output of
the motor 100, the output of the scroll compressor 300 can also
30 be increased.
[0114]
Although the scroll compressor 300 is described as an
example of the compressor, the motor described in each of the
first embodiment and modification may also be applied to
32
compressors other than the scroll compressor 300.
[0115]
(Air Conditioner)
Next, an air conditioner to which the motor of each of the
above-described first embodiment and modification 5 is applicable
will be described. FIG. 13 is a diagram showing an air
conditioner 400 (a refrigeration cycle device). The air
conditioner 400 includes a compressor 401, a condenser 402, a
throttle device (a decompression device) 403, and an evaporator
10 404. The compressor 401, the condenser 402, the throttle device
403, and the evaporator 404 are connected together by a
refrigerant pipe 407 to constitute a refrigeration cycle. That
is, the refrigerant circulates through the compressor 401, the
condenser 402, the throttle device 403, and the evaporator 404 in
15 this order.
[0116]
The compressor 401, the condenser 402, and the throttle
device 403 are provided in an outdoor unit 410. The compressor
401 is constituted by the scroll compressor 300 shown in FIG. 13.
20 The outdoor unit 410 is provided with an outdoor fan 405 that
supplies outdoor air to the condenser 402. The evaporator 404 is
provided in an indoor unit 420. The indoor unit 420 is provided
with an indoor fan 406 that supplies indoor air to the evaporator
404.
25 [0117]
An operation of the air conditioner 400 is as follows. The
compressor 401 compresses sucked refrigerant, and sends out the
compressed refrigerant. The condenser 402 exchanges heat between
the refrigerant flowing from the compressor 401 and outdoor air
30 to condense and liquefy the refrigerant and sends out the
liquefied refrigerant to the refrigerant pipe 407. The outdoor
fan 405 supplies outdoor air to the condenser 402. The throttle
device 403 adjusts the pressure or the like of the refrigerant
flowing through the refrigerant pipe 407 by changing its opening
33
degree.
[0118]
The evaporator 404 exchanges heat between the refrigerant
brought into a low-pressure state by the throttle device 403 and
the indoor air to cause the refrigerant to 5 take heat from the
indoor air and evaporate (vaporize), and then sends out the
evaporated refrigerant to the refrigerant pipe 407. The indoor
fan 406 supplies indoor air to the evaporator 404. Thus, cooled
air deprived of heat at the evaporator 404 is supplied into the
10 room.
[0119]
As described above, the motor 100 of each of the first
embodiment and the modification has the high heat dissipation
effect and thus can suppress an increase in the temperature
15 inside the compressor 401. Thus, a stable operation of the air
conditioner 400 is enabled. With the increase in output of the
compressor 401 due to the increase in output of the motor 100,
the output of the air conditioner 400 can also be increased.
[0120]
20 Although the desirable embodiment of the present invention
has been described, the present invention is not limited to the
above-described embodiment, and various modifications and changes
can be made without departing from the scope of the present
invention.
25 DESCRIPTION OF REFERENCE CHARACTERS
[0121]
1 stator; 10 stator core; 10a outer circumference; 10b
inner circumference; 11 yoke; 12 tooth; 12a tooth tip portion;
13 slot; 13a bottom portion; 13b first side portion; 13c second
30 side portion; 14 slot opening; 2 insulating portion; 3 coil;
31 aluminum wire coil (first coil); 31a conductor; 32 copper
wire coil (second coil); 32a conductor; 5 rotor; 50 rotor core;
51 slot; 55 shaft; 6 squirrel-cage secondary conductor; 61 bar;
62, 63 end ring (annular body); 100 motor; 101 first region;
34
102 second region; 300 scroll compressor (compressor); 305
compression mechanism; 307 closed container; 400 air
conditioner; 401 compressor; 402 condenser; 403 throttle device
(decompression device); 404 evaporator; 405 refrigerant pipe;
406 controller; L1 first straight line; L2 5 second straight
line; P1 first point; P2 second point; P3 third point; P4
fourth point.
35
We Claim :
1. A stator comprising:
a stator core having an inner circumference extending in a
circumferential direction about an axis, and a 5 slot formed on an
outer side of the inner circumference in a radial direction about
the axis; and
a first coil and a second coil disposed in the slot and
connected in series with each other, the first coil having a
10 conductor formed of a first metal, the second coil having a
conductor formed of a second metal that has a lower electrical
resistivity than that of the first metal,
wherein the slot comprises:
a slot opening opened to the inner circumference of the
15 stator core;
a slot bottom portion having a curved shape and disposed on
an outer side of the slot opening in the radial direction; and
a first side portion and a second side portion disposed
between the slot opening and the slot bottom portion and facing
20 each other in the circumferential direction,
wherein in a plane perpendicular to the axis, a first
straight line is defined as a straight line connecting a border
between the slot bottom portion and the first side portion and a
border between the slot bottom portion and the second side
25 portion,
wherein a first region is defined as a region surrounded by
the first straight line and the slot bottom portion,
wherein a second region is defined as a region in the slot
on an outer side of the slot opening in the radial direction and
30 on an inner side of the first straight line in the radial
direction, and
wherein an area S1 of the first region, a total crosssectional
area A1 of the first coil in the first region, an area
S2 of the second region, and a total cross-sectional area A2 of
36
the first coil in the second region satisfy the following
equation:
(A1/S1) > (A2/S2).
2. The stator according to claim 1, wherein 5 the total crosssectional
area A1 of the first coil in the first region, a total
cross-sectional area C1 of the second coil in the first region,
and the area S1 of the first region satisfy the following
equation:
10 (A1/S1) > (C1/S1).
3. The stator according to claim 1 or 2, wherein the total
cross-sectional area A1 of the first coil in the first region, a
total cross-sectional area C1 of the second coil in the first
15 region, the total cross-sectional area A2 of the first coil in
the second region, and a total cross-sectional area C2 of the
second coil in the second region satisfy the following equation:
(A1/C1) > (A2/C2).
20 4. The stator according to any one of claims 1 to 3, wherein,
of the first coil and the second coil, only the first coil is
disposed in the first region.
5. The stator according to any one of claims 1 to 4, wherein a
25 diameter of the first coil is greater than or equal to a diameter
of the second coil.
6. The stator according to any one of claims 1 to 5, wherein a
diameter DAl of the first coil, an electrical resistivity ρAl of
30 the first coil, a diameter DCu of the second coil, and an
electrical resistivity ρCu of the second coil satisfy the
following equation:
37
D���� ≤ D���� < ��
��
��
× D����.
7. The stator according to any one of claims 1 to 4, wherein a
diameter DAl of the first coil, an electrical resistivity ρAl of
the first coil, a diameter DCu of the second coil, and an
electrical resistivity ρCu of the second 5 coil satisfy the
following equation:
0.5 × D���� ≤ D���� < ��
��
��
× D����.
8. The stator according to any one of claims 1 to 7, wherein
an electrical resistance RAl of the first coil, an electrical
10 resistance RCu of the second coil, and a ratio k of a crosssectional
area of the first coil to a cross-sectional area of the
second coil satisfy the following equation:
1 ≤
������
�� × ������
.
15 9. The stator according to claim 8, wherein the ratio k is
greater than or equal to 1.
10. The stator according to claim 8, wherein the ratio k is
greater than or equal to 0.25.
20
11. The stator according to any one of claims 1 to 10, wherein
the first metal is aluminum, and the second metal is copper.
12. A motor comprising:
25 the stator according to any one of claims 1 to 11, and
a rotor rotatably provided on an inner side of the stator
in the radial direction.
13. The motor according to claim 12, wherein the motor is an
induction motor.
14. A compressor comprising:
a 5 closed container;
a compression mechanism d
and
the motor according to claim 12 or 13, the motor
the compression mechanism.
10
15. An air conditioner
claim 14, a condenser, a decompression device, and an evaporator.