FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
[See section 10, Rule 13]
MOTOR, COMPRESSOR, AND REFRIGERATION CYCLE APPARATUS
MITSUBISHI ELECTRIC CORPORATION, A CORPORATION ORGANISED AND
EXISTING UNDER THE LAWS OF JAPAN, WHOSE ADDRESS IS 7-3,
MARUNOUCHI 2-CHOME, CHIYODA-KU, TOKYO 1008310, JAPAN
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE
INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED.
2
DESCRIPTION
TECHNICAL FIELD
4 [0001]
The present disclosure relates to a motor, a compressor,
and a refrigeration cycle apparatus.
BACKGROUND ART
8 [0002]
A motor includes a rotor having a permanent magnet, and
a stator having a winding. A copper wire is generally used
for the winding, but the use of aluminum wire, which is low in
12 cost, is increasing (see, for example, Patent Reference 1).
PRIOR ART REFERENCE
PATENT REFERENCE
[0003]
16 Patent Reference 1: International Patent Publication No.
WO2017/126053 (see, for examples, paragraphs 0017-0019)
SUMMARY OF THE INVENTION
PROBLEM TO BE SOLVED BY THE INVENTION
20 [0004]
However, the aluminum wire has a higher electrical
resistance than the copper wire, and thus the use of the
aluminum wire for the winding increases the amount of heat
24 generation. When the temperature of the winding rises because
of the increase in the amount of heat generation, damage on an
insulating film of the winding or the like may occur. Thus,
it is desired to suppress a temperature rise of the winding.
28 [0005]
The present disclosure is made to solve the abovedescribed problem, and an object of the present disclosure is
to suppress a temperature rise in the case where an aluminum
32 wire is used for a winding.
MEANS OF SOLVING THE PROBLEM
[0006]
3
A motor according to the present disclosure comprises a
rotor including a rotor core having an annular shape about an
axis and formed of electromagnetic steel sheets stacked in a
4 direction of the axis and a permanent magnet attached to the
rotor core, and a stator including a stator core surrounding
the rotor core and formed of electromagnetic steel sheets
stacked in the direction of the axis and a winding wound on
8 the stator core and formed of an aluminum wire. A stacking
factor O1 of the electromagnetic steel sheets of the stator
core and a stacking factor O2 of the electromagnetic steel
sheets of the rotor core satisfy:
12 O1 < O2.
EFFECTS OF THE INVENTION
[0007]
With this configuration, since the stacking factor O1 of
16 the electromagnetic steel sheets of the stator core and the
stacking factor O2 of the electromagnetic steel sheets of the
rotor core satisfy O1 < O2, the amount of refrigerant passing
through clearances between the electromagnetic steel sheets of
20 the stator core can be made larger than the amount of
refrigerant passing through clearances between the
electromagnetic steel sheets of the rotor core. Thus, heat of
the winding can be dissipated by the refrigerant passing
24 through the clearances between the electromagnetic steel
sheets of the stator core, and a temperature rise of the
winding can be suppressed.
BRIEF DESCRIPTION OF THE DRAWINGS
28 [0008]
FIG. 1 is a transverse sectional view illustrating a
motor according to a first embodiment.
FIG. 2 is a transverse sectional view illustrating a
32 stator core according to the first embodiment.
FIG. 3 is a transverse sectional view illustrating a
split core of the first embodiment.
4
FIG. 4 is a transverse sectional view illustrating a
part of the rotor according to the first embodiment.
FIG. 5 is a longitudinal sectional view illustrating the
4 motor according to the first embodiment.
FIG. 6 is a schematic view illustrating electromagnetic
steel sheets of the stator core and a rotor core according to
the first embodiment.
8 FIGS. 7(A) and 7(B) are views illustrating configuration
examples of the stator core according to the first embodiment.
FIG. 8 is a schematic view for describing a method for
winding a winding according to the first embodiment.
12 FIG. 9 is a schematic view illustrating a winding
pattern of the winding according to the first embodiment.
FIG. 10 is a schematic view illustrating a contact
portion between the stator core and the winding in the stator
16 according to the first embodiment.
FIG. 11 is a schematic view illustrating a contact
portion between a stator core and a winding in a stator of a
comparative example.
20 FIG. 12 is a schematic view illustrating electromagnetic
steel sheets of a stator core and a rotor core according to a
second embodiment.
FIGS. 13(A) and 13(B) are schematic views for describing
24 a method for adjusting a gap between the electromagnetic steel
sheets according to the second embodiment.
FIGS. 14(A) and 14(B) are schematic views for describing
a method for adjusting a gap between the electromagnetic steel
28 sheets according to the second embodiment.
FIG. 15 is a schematic view illustrating a contact
portion between the stator core and a winding in a stator
according to the second embodiment.
32 FIG. 16 is a schematic view illustrating electromagnetic
steel sheets of a stator core and a rotor core according to a
third embodiment.
5
FIGS. 17(A) and 17(B) are respectively a perspective
view and a plan view showing a method for measuring an iron
loss of electromagnetic steel sheets according to the third
4 embodiment.
FIG. 18 is a longitudinal sectional view illustrating a
compressor to which the motor of each embodiment is applicable.
FIG. 19 is a view illustrating a refrigeration cycle
8 apparatus including the compressor of FIG. 18.
MODE FOR CARRYING OUT THE INVENTION
[0009]
FIRST EMBODIMENT
12 (Configuration of Motor)
First, a motor 100 according to a first embodiment will
be described. FIG. 1 is a transverse sectional view
illustrating the motor 100 according to the first embodiment.
16 The motor 100 illustrated in FIG. 1 is a permanent magnetembedded motor and used for, for example, a compressor. The
compressor will be described with reference to FIG. 18.
[0010]
20 The motor 100 includes a rotor 5 including a shaft 4 as
a rotation shaft, and a stator 1 surrounding the rotor 5. An
air gap of, for example, 0.3 to 1.0 mm is formed between the
stator 1 and the rotor 5. The stator 1 is incorporated in a
24 cylindrical shell 8 of the compressor.
[0011]
In the following description, a direction of an axis Ax
that is a rotation center axis of the rotor 5 is referred to
28 as an “axial direction.” A radial direction about the axis Ax
is referred to as a “radial direction.” A circumferential
direction about the axis Ax is referred to as a
“circumferential direction.” A sectional view in a plane
32 parallel to the axis Ax is referred to as a longitudinal
sectional view, and a sectional view in a plane orthogonal to
the axis Ax is referred to as a transverse sectional view.
6
[0012]
(Configuration of Stator)
The stator 1 includes a stator core 10 and a winding 2
4 wound on the stator core 10. FIG. 2 is a sectional view
illustrating the stator core 10. The stator core 10 is
configured so that electromagnetic steel sheets 101 (FIG. 5)
are stacked in the axial direction and fixed together by
8 crimping portions 17 and 18 (FIG. 3). Front and back surfaces
of the electromagnetic steel sheets 101 are coated with notshown insulating films. Each of the electromagnetic steel
sheets 101 has a thickness of 0.1 to 0.7 [mm], which will be
12 described later.
[0013]
The stator core 10 includes an annular yoke 11 and a
plurality of teeth 12 extending inward in the radial direction
16 from the yoke 11. The teeth 12 are arranged at equal
intervals in the circumferential direction. The number of the
teeth 12 is nine in this example, but is not limited to nine.
[0014]
20 Each tooth 12 has a tooth tip 12a whose width in the
circumferential direction is wider than the other portions of
the tooth 12. The tooth tip 12a is located at the inner side
of the tooth 12 in the radial direction. The tooth tip 12a
24 faces the outer circumference of the rotor 5 (FIG. 1). A
portion between the tooth tip 12a of the tooth 12 and the yoke
11 is referred to as an extension portion 12b. The width of
the extension portion 12b in the circumferential direction is
28 uniform. Slots 13 are formed between the teeth 12 that are
adjacent to each other in the circumferential direction. Each
slot 13 is a region in which the winding 2 wound around the
tooth 12 is housed.
32 [0015]
The stator core 10 is formed by coupling a plurality of
split cores 9 in an annular shape. Each of the split cores 9
7
is a block including a corresponding one of the teeth 12. The
split cores 9 are divided at split faces 15 formed in the yoke
11. The number of the split cores 9 is equal to the number of
4 the teeth 12, and is nine in this example.
[0016]
The stator core 10 is not limited to the configuration
in which the split cores 9 are coupled in the annular shape.
8 The stator core 10 may be configured so that electromagnetic
steel sheets each punched into an annular shape are stacked.
[0017]
FIG. 3 is a view illustrating one of the split cores 9
12 of the stator core 10. In the split core 9, a recess 19 is
formed on an outer periphery 11a of the yoke 11. The recess
19 forms a refrigerant passage between the stator core 10 and
the shell 8 (FIG. 1). The recess 19 is disposed on a straight
16 line E passing in the radial direction through the center of
the tooth 12 in the width direction in this example, but the
position of the recess 19 is not limited to this position.
[0018]
20 Through holes 16 are formed in the yoke 11. Each
through hole 16 is formed from one end to the other end of the
stator core 10 in the axial direction and allows refrigerant
of the compressor to pass. The through hole 16 is located on
24 the straight line E passing through the center of the tooth 12
in the width direction and at the inner side of the recess 19
in the radial direction, but the position of the through hole
16 is not limited to this position. The sectional shape of
28 the through hole 16 is semicircular in this example, and a
portion of the through hole 16 in the form of a cord faces the
recess 19. The sectional shape of the through hole 16 is not
limited to a semicircular shape.
32 [0019]
The crimping portions 17 and the crimping portions 18
for fixing the electromagnetic steel sheets 101 are formed in
8
the yoke 11. Each crimping portion 17 is located at the inner
side of the through hole 16 in the radial direction. The
crimping portions 18 are located at both sides of the through
4 hole 16 in the circumferential direction. The positions of
the crimping portions 17 and 18 are not limited to these
positions. The crimping portion 17 is a round crimping, and
the crimping portion 18 is a V-crimping, but the crimping
8 portions 17 and 18 are not limited to these types.
[0020]
As illustrated in FIG. 1, the winding 2 is formed of a
magnet wire and is wound around each tooth 12 by concentrated
12 winding. The magnet wire is formed of an aluminum wire. The
aluminum wire is formed of an aluminum conductor covered with
an insulating film.
[0021]
16 The magnet wire (aluminum wire in this example)
constituting the winding 2 has a wire diameter of, for example,
1.0 mm. The number of turns of the winding 2 around one tooth
12 is, for example, 80 turns. The wire diameter and the
20 number of turns of the winding 2 are determined depending on
required characteristics of the motor 100 (for example, the
number of rotations and torque), the supply voltage, and a
sectional area of the slots 13.
24 [0022]
An insulating portion 3 is provided for insulating the
stator core 10 and the winding 2 from each other. The
insulating portion 3 includes insulators 31 disposed at both
28 ends of the stator core 10 in the axial direction, and
insulating films 32 disposed on inner surfaces of the slots 13.
[0023]
The insulators 31 are formed of a resin such as
32 polybutylene terephthalate (PBT). The insulating film 32 is
formed of a resin such as polyethylene terephthalate (PET) and
has a thickness of 0.1 to 0.8 [mm]. The winding 2 is wound
9
around the tooth 12 via the insulators 21 and the insulating
films 32.
[0024]
4 (Configuration of Rotor 5)
The rotor 5 includes a rotor core 50 having an annular
shape about the axis Ax, and permanent magnets 55 attached to
the rotor core 50. The rotor core 50 is configured so that
8 electromagnetic steel sheets 501 (FIG. 5) are stacked in the
axial direction and fixed together by crimping portions 58
(FIG. 4). Front and back surfaces of the electromagnetic
steel sheets 501 are coated with not-shown insulating films.
12 Each of the electromagnetic steel sheets 501 has a thickness
of 0.1 to 0.7 [mm], which will be described later.
[0025]
A center hole 54 is formed at the center of the rotor
16 core 50 in the radial direction. The shaft 4 described above
is fixed in the center hole 54 of the rotor core 50 by, for
example, shrink fitting or press fitting. The rotor core 50
also has a circumferential outer periphery 50a.
20 [0026]
A plurality of magnet insertion holes 51 are formed
along the outer periphery 50a of the rotor core 50. One
permanent magnet 55 is disposed in each of the magnet
24 insertion holes 51. Each magnet insertion hole 51 corresponds
to one magnetic pole. Since the rotor core 50 has six magnet
insertion holes 51, the number of poles of the rotor 5 is six.
[0027]
28 The number of poles of the rotor 5 is not limited to six,
and only needs to be two or more. Two or more permanent
magnets 55 may be disposed in each of the magnet insertion
holes 51. Each of the magnet insertion holes 51 may Fextend
32 in a V shape.
[0028]
Each of the permanent magnets 55 has a flat plate member
10
elongated in the axial direction of the rotor core 50, and has
a width in the circumferential direction and a thickness in
the radial direction. Each of the permanent magnets 55 is
4 magnetized in the thickness direction. The permanent magnet
55 is constituted by a rare earth magnet containing neodymium
(Nd), iron (Fe), and boron (B), for example.
[0029]
8 The rare earth magnet has a property in which a coercive
force decreases with a temperature rise, and the decreasing
rate is -0.5 to -0.6 [%/K]. To avoid demagnetization of the
rare earth magnets when a maximum load expected in the
12 compressor occurs, a coercive force of 1100 to 1500 [A/m] is
needed. To obtain this coercive force at an ambient
temperature of 150°C, a coercive force at room temperature,
that is, 20 [°C], needs to be 1800 to 2300 [A/m].
16 [0030]
Thus, dysprosium (Dy) may be added to the rare earth
magnet. The coercive force of the rare earth magnet at room
temperature is 1800 [A/m] without addition of Dy, and is 2300
20 [A/m] when 2 [wt%] of Dy is added. However, the addition of
Dy causes an increase in manufacturing cost and a decrease in
residual magnetic flux density, and thus it is desirable to
add as least Dy as possible or not to add Dy.
24 [0031]
FIG. 4 is an enlarged view illustrating a portion of the
rotor 5. Each of the magnet insertion holes 51 extends
linearly in a direction orthogonal to a line in the radial
28 direction passing through the center of the magnet insertion
hole 51 in the circumferential direction. The center of the
magnet insertion hole 51 in the circumferential direction is a
magnetic pole center P. The line passing in the radial
32 direction through the magnetic pole center P is referred to as
a magnetic pole center line. An inter-pole portion M is
formed between adjacent magnetic poles.
11
[0032]
Flux barriers 52 that are openings are formed at both
sides of each magnet insertion hole 51 in the circumferential
4 direction. A bridge 53 that is a thin portion is formed
between each flux barrier 52 and the outer periphery 50a of
the rotor core 50. The bridge 53 has a width W in the radial
direction, which will be described later.
8 [0033]
Slits 59 each elongated in the radial direction are
formed at the outer side of the magnet insertion hole 51 in
the radial direction. The slits 59 are formed to control
12 magnetic flux density distribution at the surface of the rotor
5. Seven slits 59 are formed symmetrically with respect to
the magnetic pole center line in this example, but the number
and arrangement of the slits 59 may be varied. It is also
16 possible that the rotor core 50 has no slit 59.
[0034]
Through holes 56 and 57 are formed at the inner side of
the magnet insertion holes 51 in the radial direction. Each
20 of the through holes 56 and 57 is formed from one end to the
other end in the axial direction of the rotor core 50, and
forms a refrigerant passage. The position of the through hole
56 in the circumferential direction coincides with the
24 magnetic pole center P, and the position of the through hole
57 in the circumferential direction coincides with the interpole portion M. However, the positions of the through holes
56 and 57 are not limited to these positions. It is also
28 possible that the rotor core 50 does not have the through hole
56 or 57.
[0035]
The crimping portion 58 for fixing the electromagnetic
32 steel sheets 501 is formed at a position corresponding to the
inter-pole portion M in the circumferential direction and on
the inner side of the corresponding flux barrier 52 in the
12
radial direction. The position of the crimping portion 58 is
not limited to this position. The crimping portion 58 is not
shown in FIG. 1.
4 [0036]
(Configuration for Suppressing Temperature Rise of Winding 2)
FIG. 5 is a longitudinal sectional view illustrating the
motor 100. The insulators 31 described above are disposed at
8 both ends of the stator core 10 in the axial direction. Each
of the insulators 31 includes an outer peripheral wall 31a, an
inner peripheral wall 31c, and a body 31b.
[0037]
12 The outer peripheral wall 31a of the insulator 31 is
located on the yoke 11 (FIG. 3), the inner peripheral wall 31c
is located on the tooth tip 12a of the tooth 12 (FIG. 3), and
the body 31b is located on the extension portion 12b of the
16 tooth 12 (FIG. 3). The winding 2 is wound around the body 31b
and guided by the outer peripheral wall 31a and the inner
peripheral wall 31c from both sides in the radial direction.
[0038]
20 A length of the stator core 10 in the axial direction is
denoted by H1. A length of the rotor core 50 in the axial
direction is denoted by H2. In this example, the length H1 of
the stator core 10 is shorter than the length H2 of the rotor
24 core 50. That is, H1 < H2 is satisfied. However, this
embodiment is not limited to such a configuration, and the
length H1 of the stator core 10 may be equal to or longer than
the length H2 of the rotor core 50.
28 [0039]
The outer periphery of the stator core 10, that is, the
outer periphery 11a of the yoke 11, is fixed to the inner
periphery of the shell 8 of the compressor. A refrigerant
32 passage is formed between the stator core 10 and the shell 8
by the recess 19 (FIG. 3) described above.
[0040]
13
FIG. 6 is a schematic view illustrating the
electromagnetic steel sheets 101 and 501 of the stator core 10
and the rotor core 50. Each of the electromagnetic steel
4 sheets 101 constituting the stator core 10 has a thickness T1.
Each of the electromagnetic steel sheets 501 constituting the
rotor core 50 has a thickness T2. In the first embodiment,
the thickness T1 of each electromagnetic steel sheet 101 is
8 thinner than the thickness T2 of each electromagnetic steel
sheet 501. That is, T1 < T2 is satisfied.
[0041]
As an example, the thickness T1 of each electromagnetic
12 steel sheet 101 is 0.35 [mm], and the thickness T2 of each
electromagnetic steel sheet 501 is 0.5 [mm].
[0042]
A stacking gap L1 between the electromagnetic steel
16 sheets 101 of the stator core 10 is equal to a stacking gap L2
between the electromagnetic steel sheets 501 of the rotor core
50 (i.e., L1 = L2). The stacking gap L1 is a gap between the
electromagnetic steel sheets 101 adjacent to each other in the
20 axial direction. The stacking gap L2 is a gap between the
electromagnetic steel sheets 501 adjacent to each other in the
axial direction. Each of the stacking gaps L1 and L2 is a
value on the order of 10 [μm], that is, on the order of 10-2
24 [mm].
[0043]
In a case where the gap between adjacent ones of the
electromagnetic steel sheets 101 is not uniform in a plane
28 orthogonal to the axis Ax, an average value thereof is used as
the stacking gap L1. Similarly, in a case where the gap
between adjacent ones of the electromagnetic steel sheets 501
is not uniform in a plane orthogonal to the axis Ax, an
32 average value thereof is used as the stacking gap L2.
[0044]
In the first embodiment, the electromagnetic steel
14
sheets 101 of the stator core 10 and the electromagnetic steel
sheets 501 of the rotor core 50 are formed of the same
material, and thus, has the same silicon content. An example
4 in which the electromagnetic steel sheets 101 and 501 have
different silicon contents will be described in a third
embodiment.
[0045]
8 A space factor of the electromagnetic steel sheets 101
per a unit length of the stator core 10 in the axial direction
is defined as a stacking factor O1 of the stator core 10. The
stacking factor O1 is obtained by O1 = H1/(T1 × n1) × 100[%],
12 based on the length H1 of the stator core 10 in the axial
direction, the thickness T1 of each electromagnetic steel
sheet 101, and the number n1 of the electromagnetic steel
sheets 101.
16 [0046]
For example, in a case where the stacking factor O1 of
the stator core 10 is 90[%], it means that clearances occupy
10[%] of the length of the stator core 10 in the axial
20 direction.
[0047]
To obtain the stacking factor O1, the thickness T1 of
one electromagnetic steel sheet 101 is first measured, and
24 then, n1 electromagnetic steel sheets 101 are stacked to form
the stator core 10. Thereafter, the length H1 of the stator
core 10 is measured, and the stacking factor O1 is calculated
from the above equation.
28 [0048]
A space factor of the electromagnetic steel sheets 501
per a unit length of the rotor core 50 in the axial direction
is defined as a stacking factor O2 of the rotor core 50. The
32 stacking factor O2 is obtained by O2 = H2/(T2 × n2) × 100[%],
based on the length H2 of the rotor core 50 in the axial
direction, the thickness T2 of each electromagnetic steel
15
sheet 501, and the number n2 of the electromagnetic steel
sheets 501.
[0049]
4 To obtain the stacking factor O2, the thickness T2 of
one electromagnetic steel sheet 501 is first measured, and
then, n2 electromagnetic steel sheets 501 are stacked to form
the rotor core 50. Thereafter, the length H2 of the rotor
8 core 50 is measured, and the stacking factor O2 is calculated
from the above equation.
[0050]
The stacking factor O1 of the stator core 10 is smaller
12 than the stacking factor O2 of the rotor core 50. In other
words, O1 < O2 is satisfied. As an example, the stacking
factor O1 is 95[%], and the stacking factor O2 is 97[%].
[0051]
16 Since the stacking factor O1 of the stator core 10 is
smaller than the stacking factor O2 of the rotor core 50, the
sum of clearances between the electromagnetic steel sheets 101
of the stator core 101 per a unit length in the axial
20 direction is larger than the sum of clearances between the
electromagnetic steel sheets 501 of the rotor core 50 per a
unit length in the axial direction. Accordingly, the amount
of refrigerant flowing through the stator core 10 increases as
24 described later, and the effect of suppressing a temperature
rise of the winding 2 is obtained.
[0052]
The term “stacking gap” refers to a gap [mm] between the
28 electromagnetic steel sheets adjacent to each other in the
axial direction. On the other hand, the term “clearance
between electromagnetic steel sheets” refers to a region
sandwiched between the electromagnetic steel sheets adjacent
32 to each other in the axial direction.
[0053]
(Method for Manufacturing Motor)
16
Next, a method for manufacturing the motor 100 according
to the first embodiment will be described. First, the
electromagnetic steel sheets 101 are punched by press work
4 into a shape in which the split cores 9 are arranged linearly
as illustrated in FIG. 7(A). In the example illustrated in
FIG. 7(A), the split cores 9 are coupled to each other at
coupling portions C on the outer peripheral side of the split
8 faces 15. In this regard, as illustrated in FIG. 7(B), the
split cores 9 may be separated from each other.
[0054]
Thereafter, the punched electromagnetic steel sheets 101
12 are stacked in the axial direction and fixed by the crimping
portions 17 and 18 to form a stacked body. The insulating
portion 3 is attached to the stacked body, and the winding 2
is wound around each of the teeth 12.
16 [0055]
The methods for winding the winding 2 include
concentrated winding and distributed winding. Concentrated
winding is employed in this example. In particular, the
20 winding 2 is not wound over a plurality of teeth 12 but is
wound around each of the teeth 12. Such a winding method is
called salient pole concentrated winding.
[0056]
24 FIG. 8 is a schematic view for describing the winding
method of the winding 2. FIG. 8 is a view of the insulator 31
seen from one side in the axial direction. In FIG. 8, the
circumferential direction is indicated by arrow A. The
28 winding 2 is wound by using a winding nozzle around the tooth
12 via the insulator 31 and the insulating film 32 (FIG. 1).
[0057]
As indicated by arrow B1, a first layer of the winding 2
32 is wound from the inner peripheral wall 31c toward the outer
peripheral wall 31a of the insulator 31. As indicated by
arrow B2, a second layer of the winding 2 is wound from the
17
outer peripheral wall 31a toward the inner peripheral wall 31c
of the insulator 31. The directions of arrows B1 and B2 may
be reversed.
4 [0058]
FIG. 9 is a sectional view illustrating a winding
pattern of the winding 2 in a plane orthogonal to the axis Ax.
In FIG. 9, the circumferential direction is indicated by arrow
8 A, and the radial direction is indicated by arrow R. Coils in
the first layer, the second layer, a third layer, and a fourth
layer of the winding 2 are denoted by characters C1, C2, C3,
and C4, respectively.
12 [0059]
The winding 2 is wound by regular winding. Specifically,
when n represents an integer of one or more, the coil Cn+1 in
the (n+1)th layer is disposed so that the coil Cn+1 is in
contact with two coils Cn in the nth 16 layer. Since the winding
2 is wound by regular winding, adhesiveness between the
winding 2 and the tooth 12 increases.
[0060]
A cross point CP at which the coil Cn in the nth 20 layer
of the winding 2 and the coil Cn+1 in the (n+1)th layer
intersect with each other is located on one end surface of the
tooth 12 in the axial direction. On the other hand, coils of
24 the winding 2 located in the slot 13 extend in the axial
direction. Accordingly, adhesiveness between the winding 2
and the side surface of the tooth 12, that is, the surface
facing the slot 13, is especially high.
28 [0061]
After the winding 2 is wound around each of the teeth 12
in the manner described above, the split cores 9 are coupled
in an annular shape. In the case where the split cores 9 are
32 coupled in the coupling portions C as illustrated in FIG. 7(A),
the split cores 9 at both ends in the arrangement direction
are welded at the split faces 15. In the case where the split
18
cores 9 are separated from each other as illustrated in FIG.
7(B), the split cores 9 are welded to each other at the split
faces 15.
4 [0062]
Through the foregoing steps, the stator 1 in which the
winding 2 is wound on the stator core 10 is completed.
[0063]
8 Concurrently with the assembly of the stator 1, assembly
of the rotor 5 is performed. Specifically, the
electromagnetic steel sheets 501 are stacked in the axial
direction and fixed at the crimping portions 58 to thereby
12 form the rotor core 50. The permanent magnets 55 are inserted
into the magnet insertion holes 51 of the rotor core 50. A
balance weight may be attached to the rotor core 50 when
necessary. In this manner, the rotor 5 is completed.
16 [0064]
Subsequently, the rotor 5 is incorporated in the stator
1. In this manner, the motor 100 is completed. In this
example, the winding 2 is wound around the teeth 12 of the
20 split cores 9 and then the split cores 9 are combined in the
annular shape. However, the winding 2 may be wound around the
teeth 12 of the annular stator core 10.
[0065]
24 (Function)
Next, function of the first embodiment will be described.
FIG. 10 is a schematic view illustrating a contact portion
between the stator core 10 and the winding 2 in the stator 1
28 according to the first embodiment. FIG. 11 is a schematic
view illustrating a contact portion between a stator core 10
and a winding 2 in a stator 1C of a comparative example.
[0066]
32 FIGS. 10 and 11 each show a cross section taken along a
plane crossing the slot 13 of the stator 1 (FIG. 3) in the
radial direction. The inner side in the radial direction,
19
that is, the side closer to the tooth tip 12a of the tooth 12,
is indicated by arrow Ri, and the outer side in the radial
direction, that is, the side closer to the yoke 11, is
4 indicated by arrow Ro. The direction of the axis Ax is
indicated by arrow Ax.
[0067]
In each of FIGS. 10 and 11, clearances 102 are formed
8 between the electromagnetic steel sheets 101 adjacent to each
other in the axial direction. In the compressor, refrigerant
flows through the refrigerant passage between the recess 19 of
the stator core 10 (FIG. 3) and the shell 8, and a part of the
12 refrigerant flows through the clearances 102 of the stator
core 10, as indicated by arrow F.
[0068]
The refrigerant flowing through the clearances 102 of
16 the stator core 10 flows to the inner side in the radial
direction to pass by the winding 2. This refrigerant has the
function of dissipating heat of the winding 2. Although the
insulating film 32 is interposed between the stator core 10
20 and the winding 2, the insulating film 32 has small influence
on heat dissipation from the winding 2 by the refrigerant
since the thickness of the insulation film 32 is thin.
[0069]
24 A thickness Tc of each electromagnetic steel sheet 101
of the stator core 101 of the comparative example illustrated
in FIG. 11 is thicker than the thickness T1 of each
electromagnetic steel sheet 101 of the stator core 10
28 according to the first embodiment. Thus, in the first
embodiment, the number of clearances 102 per a unit length of
the stator core 10 in the axial direction is larger than that
in the comparative example. That is, the stacking factor O1
32 of the electromagnetic steel sheets 101 of the stator core 10
according to the first embodiment is smaller than the stacking
factor Oc of the electromagnetic steel sheets 101 of the
20
stator core 10 of the comparative example.
[0070]
As the stacking factor decreases, the sum of the
4 clearances 102 per a unit length in the axial direction
increases, and accordingly, the flow rate of refrigerant
flowing through the clearances 102 increases. In the first
embodiment, the thickness T1 of each electromagnetic steel
8 sheet 101 is thin, and thus the stacking factor O1 is small.
Accordingly, the amount of refrigerant flowing through the
clearances 102 of the stator core 10 is larger than that in
the comparative example.
12 [0071]
Since the winding 2 is formed of an aluminum wire having
a higher electrical resistance than a copper wire, the amount
of heat generation when current flows through the winding 2 is
16 large. In the first embodiment, heat of the winding 2 can be
efficiently dissipated by refrigerant, and thereby, a
temperature rise of the winding 2 can be suppressed.
[0072]
20 In addition, the stator core 10 has the through holes 16
(FIG. 3), and refrigerant also flows into the clearances 102
from the through holes 16. Thus, the amount of refrigerant
flowing through the clearances 102 can be increased, and the
24 effect of suppressing a temperature rise of the winding 2 can
thereby be enhanced.
[0073]
The number and arrangement of the through holes 16 in
28 the stator core 10 may be varied. In this regard, the through
holes 16 interrupt magnetic fluxes flowing through the stator
core 10, and thus, the through holes 16 are preferably formed
in the yoke 11 rather than the teeth 12 where magnetic fluxes
32 are concentrated.
[0074]
In particular, as illustrated in FIG. 3, in the case
21
where the through hole 16 is disposed on the straight line E
in the radial direction passing through the center in the
circumferential direction of the tooth 12 in the yoke 11, it
4 is possible to minimize interference of magnetic fluxes while
obtaining a sufficient flow rate of refrigerant.
[0075]
The insulator 31 is located at a position covering the
8 through hole 16 of the stator core 10 in FIG. 1. However, as
indicated by broken lines in FIG. 3, the insulator 31 may be
disposed at a position not covering the through hole 16 (that
is, at a position at which the through hole 16 is exposed).
12 In this case, refrigerant easily flows into the through hole
16 and the effect of suppressing a temperature rise of the
winding 2 can be further enhanced.
[0076]
16 However, even in the case where the through hole 16 is
covered with the insulator 31 (FIG. 1), refrigerant flows into
the through hole 16 by way of the clearances 102 from the
recess 19, and thus the effect of suppressing a temperature
20 rise of the winding 2 by refrigerant can still be obtained.
[0077]
In general, as the thickness of an electromagnetic steel
sheet decreases, an iron loss occurring in the electromagnetic
24 steel sheet decreases. In the first embodiment, the thickness
T1 of each electromagnetic steel sheet 101 of the stator core
10 is thinner than the thickness T2 of each electromagnetic
steel sheet 501 of the rotor core 50, and thus an iron loss in
28 the stator core 10 can be reduced, so that a temperature rise
in the stator core 10 can thereby be suppressed.
[0078]
Since a temperature rise of the stator core 10 is
32 suppressed, refrigerant is less likely to be heated while the
refrigerant passes through the clearances 102 of the stator
core 10. Accordingly, the heat dissipation effect of the
22
winding 2 by refrigerant can be enhanced, and the effect of
suppressing a temperature rise of the winding 2 can be
enhanced.
4 [0079]
When the stator core 10 and the rotor core 50 are
compared, an iron loss occurring in the stator core 10 is
larger than an iron loss occurring in the rotor core 50. This
8 is because the relative position of the stator core 10 to
magnetic fluxes of the permanent magnets 55 significantly
changes during rotation of the rotor 5.
[0080]
12 It is generally known that an iron loss occurring in the
stator core 10 is two to four times as large as an iron loss
occurring in the rotor core 50. It is also known that an iron
loss is inversely proportional to the first to second power of
16 the thickness of the electromagnetic steel sheet. Thus, when
the thickness T2 of each electromagnetic steel sheet 501 of
the rotor core 50 is set to be √2 times to 4 times of the
thickness T1 of each electromagnetic steel sheet 101 of the
20 stator core 10, equivalent iron loss occurs in the stator core
10 and the rotor core 50.
[0081]
The √2 times, which is the lower limit, is a value in a
24 case where an iron loss occurring in the stator core 10 is
twice as large as an iron loss occurring in the rotor core 50
and an iron loss is inversely proportional to the second power
of the thickness of the electromagnetic steel sheet. The four
28 times, which is the upper limit, is a value in a case where an
iron loss occurring in the stator core 10 is four times as
larger as an iron loss occurring in the rotor core 50 and an
iron loss is inversely proportional to the first power of the
32 thickness of the electromagnetic steel sheet.
[0082]
On the other hand, when the thickness T2 of each
23
electromagnetic steel sheet 501 of the rotor core 50 exceeds
four times the thickness T1 of each electromagnetic steel
sheet 101 of the stator core 10, an iron loss occurring in the
4 rotor core 50 may exceed an iron loss occurring in the stator
core 10. Consequently, heat of the rotor core 50 is
transferred to the stator core 10, and the effect of
suppressing a temperature rise of the winding 2 may degrade.
8 For this reason, the thicknesses T1 and T2 preferably satisfy
T2 < 4 × T1.
[0083]
As illustrated in FIG. 4, a width W of the bridge 53 in
12 the radial direction between the flux barrier 52 and the outer
periphery 50a of the rotor core 50 is preferably less than or
equal to the thickness T1 of each electromagnetic steel sheet
101 of the stator core 10. That is, W < T1 is preferably
16 satisfied. This will be described later.
[0084]
When the motor 100 is driven, a current with a frequency
synchronized to the rotation speed is supplied to the winding
20 2 of the stator 1 so that a rotating magnetic field is thereby
generated to cause the rotor 5 to rotate. At this time, a
part of magnetic fluxes flowing from the tooth 12 to the rotor
core 50 passes through the bridge 53 of the rotor core 50 and
24 flows back to the adjacent tooth 12. That is, a short-circuit
path passing through the bridge 53 is formed.
[0085]
Magnetic fluxes flowing through the short-circuit path
28 do not contribute to rotation of the rotor 5 and may cause an
iron loss in the tooth tip 12a of the tooth 12. When the iron
loss occurs in the tooth tip 12a, the temperature of the
stator core 10 may rise and the effect of suppressing a
32 temperature rise of the winding 2 may be degraded. Thus, it
is desirable to reduce magnetic fluxes flowing through the
short-circuit path.
24
[0086]
The range of magnetic fluxes flowing through the bridge
53 in the axial direction is restricted by the thickness T1 of
4 each electromagnetic steel sheet 101 of the stator core 10.
The front and back surfaces of the electromagnetic steel
sheets 101 and 501 are coated with insulating films, and
magnetic fluxes flowing through one electromagnetic steel
8 sheet 501 in the axial direction do not flow to the adjacent
electromagnetic steel sheet 501 in the axial direction but
flows to the electromagnetic steel sheets 101 of the stator
core 10.
12 [0087]
On the other hand, magnetic fluxes flowing through the
bridge 53 in the radial direction are restricted by the width
W of the bridge 53 in the radial direction. When the radial
16 width W of the bridge 53 is narrower than the thickness T1
described above, a flow of magnetic fluxes in the radial
direction can be restricted. As a result of restriction of
magnetic fluxes flowing from the stator core 10 toward the
20 rotor core 50, magnetic fluxes flowing through the shortcircuit path can be reduced, and degradation of the effect of
suppressing a temperature rise of the winding 2 can be reduced.
[0088]
24 (Advantages of Embodiment)
As described above, the motor 100 according to the first
embodiment includes the rotor 5 including the rotor core 50
and the permanent magnets 55, and the stator 1 including the
28 stator core 10 and the winding 2. The stacking factor O1 of
the electromagnetic steel sheets 101 of the stator core 10 and
the stacking factor O2 of the electromagnetic steel sheets 501
of the rotor core 50 satisfy O1 < O2. Thus, the amount of
32 refrigerant flowing through the clearances 102 between the
electromagnetic steel sheets 101 of the stator core 10 is
increased, and heat of the winding 2 can be taken by the
25
refrigerant, so that a temperature rise of the winding 2 can
be suppressed.
[0089]
4 In addition, since the thickness T1 of each
electromagnetic steel sheet 101 of the stator core 10 is
thinner than the thickness T2 of each electromagnetic steel
sheet 501 of the rotor core 50, the number of the clearances
8 102 of the stator core 10 per a unit length in the axial
direction is large. Accordingly, the amount of refrigerant
passing through the clearances 102 can be increased.
Furthermore, since the thickness T1 is thin, occurrence of an
12 iron loss in the stator core 10 can be suppressed, and a
temperature rise of the stator core 10 can be suppressed. As
a result, the effect of suppressing a temperature rise of the
winding 2 can be enhanced.
16 [0090]
Since the thickness T1 and the thickness T2 satisfy T2 <
4 × T1, a temperature rise due to an iron loss occurring in
the rotor core 50 can be suppressed, and a temperature rise of
20 the winding 2 caused by heat transfer from the rotor core 50
to the stator core 10 can be suppressed.
[0091]
Since the width W of the bridge 53 of the rotor core 50
24 in the radial direction is smaller than the thickness T1 of
each electromagnetic steel sheet 101 of the stator core 10,
magnetic fluxes flowing between the teeth 12 by way of the
short-circuit path can be reduced. Accordingly, occurrence of
28 an iron loss in the tooth tip 12a is suppressed, and the
effect of suppressing a temperature rise of the winding 2 can
be enhanced.
[0092]
32 The stator core 10 includes the through holes 16 formed
from one end to the other end of the stator core 10 in the
axial direction. Thus, refrigerant in the compressor easily
26
flows into the clearances 102 via the through holes 16, and
the effect of suppressing a temperature rise of the winding 2
can thereby be enhanced.
4 [0093]
The stator core 10 includes the recess 19 forming the
refrigerant passage between the stator core 10 and the inner
peripheral surface the shell 8 of the compressor. Thus,
8 refrigerant in the compressor easily flows into the clearances
102 via the recess 19, and the effect of suppressing a
temperature rise of the winding 2 can thereby be enhanced.
[0094]
12 Since the winding 2 is wound around the teeth 12 by
salient pole concentrated winding, adhesiveness between the
winding 2 and the teeth 12 increases. Accordingly, a larger
part of refrigerant passing through the clearances 102
16 contacts the winding 2, and the effect of suppressing a
temperature rise of the winding 2 can thereby be enhanced.
[0095]
In addition, since the stator core 10 is constituted by
20 the plurality of split cores 9, the winding 2 can be wound
around the teeth 12 before the split cores 9 are combined in
the annular shape. Accordingly, flexibility in movement of
the winding nozzle is large, and the winding 2 can be wound
24 with high density. As a result, adhesiveness between the
winding 2 and the teeth 12 increases, and the effect of
suppressing a temperature rise of the winding 2 can thereby be
enhanced.
28 [0096]
SECOND EMBODIMENT
Next, a second embodiment will be described. FIG. 12 is
a schematic view illustrating a stator core 10A of a stator 1A
32 and a rotor core 50A of a rotor 5A according to the second
embodiment. In the second embodiment, a stacking gap L1
between electromagnetic steel sheets 101 of the stator core
27
10A is wider than a stacking gap L2 between electromagnetic
steel sheets 501 of the rotor core 50A. That is, L1 > L2 is
satisfied.
4 [0097]
A thickness T1 of each electromagnetic steel sheet 101
of the stator core 10A is equal to a thickness T2 of each
electromagnetic steel sheet 501 of the rotor core 50A. That
8 is, T1 = T2 is satisfied. The thickness T1 of each
electromagnetic steel sheet 101 of the stator core 10A may be
thinner than the thickness T2 of each electromagnetic steel
sheet 501 of the rotor core 50A as in the first embodiment.
12 [0098]
In the second embodiment, a stacking factor O1 of the
electromagnetic steel sheets 101 of the stator core 10A is
smaller than a stacking factor O2 of the electromagnetic steel
16 sheets 501 of the rotor core 50A. That is, O1 < O2 is
satisfied.
[0099]
The stacking gap L1 between the electromagnetic steel
20 sheets 101 can be adjusted in forming the crimping portions 17
and 18 (FIG. 3). Each of the crimping portions 17 and 18 can
be formed by performing press work on the electromagnetic
steel sheets 101.
24 [0100]
FIGS. 13(A) and 13(B) are respectively a plan view and a
sectional view schematically illustrating the crimping portion
18 that is a V-crimping. A V-shaped protrusion 18a formed on
28 the back surface of each electromagnetic steel sheet 101 is
fitted in a V-shaped recess 18b formed on the front surface of
its underlying electromagnetic steel sheet 101, so that the
plurality of electromagnetic steel sheets 101 can thereby be
32 fixed to each other. In the press work, the protruding amount
of the protrusion 18a, that is, the depth of the recess 18b
(hereinafter referred to as a crimping depth D), is adjusted
28
to thereby adjust the stacking gap L1 between the
electromagnetic steel sheets 101.
[0101]
4 FIGS. 14(A) and 14(B) are respectively a plan view and a
sectional view schematically illustrating the crimping portion
17 that is a round crimping. A cylindrical protrusion 17a
formed on the back surface of each electromagnetic steel sheet
8 101 is fitted in a cylindrical recess 17b formed on the front
surface of its underlying electromagnetic steel sheet 101, so
that the plurality of electromagnetic steel sheets 101 can
thereby be fixed to each other. In the press work, the degree
12 of the protrusion 17a, that is, the depth of the recess 17b
(hereinafter referred to as a crimping depth) D, is adjusted
to thereby adjust the stacking gap L1 between the
electromagnetic steel sheets 101.
16 [0102]
While FIG. 13(A) through FIG. 14(B) show the crimping
portions 17 and 18 of the electromagnetic steel sheets 101 of
the stator core 10A, the stacking gap L2 between the
20 electromagnetic steel sheets 501 of the rotor core 50A can
also be adjusted similarly.
[0103]
In the second embodiment, the crimping depth D of each
24 electromagnetic steel sheet 101 of the stator core 10A is made
deeper than the crimping depth D of each electromagnetic steel
sheet 501 of the rotor core 50A, and thus the stacking gap L1
between the electromagnetic steel sheets 101 is wider than the
28 stacking gap L2 between the electromagnetic steel sheets 501.
[0104]
FIG. 15 is a schematic view illustrating a contact
portion between the stator core 10A and a winding 2 in the
32 stator 1 according to the second embodiment. FIG. 15 shows a
cross section taken along a plane crossing the slot 13 in the
radial direction. The inner side in the radial direction,
29
that is, the side closer to the tooth tip 12a, is indicated by
arrow Ri, and the outer side in the radial direction, that is,
the side closer to the yoke 11, is indicated by arrow Ro. The
4 direction of the axis Ax is indicated by arrow Ax.
[0105]
As described above, the stacking gap L1 between the
electromagnetic steel sheets 101 of the stator core 10A is
8 wider than the stacking gap L2 between the electromagnetic
steel sheets 502 of the rotor core 50A (FIG. 15) in the first
embodiment. Thus, the amount of refrigerant flowing through
the clearances 102 of the stator core 10A can be increased,
12 and accordingly, the efficiency in suppressing a temperature
rise of the winding 2 can be enhanced.
[0106]
Except for the aspects described above, the motor
16 according to the second embodiment is configured similarly to
the motor 100 according to the first embodiment.
[0107]
As described above, in the second embodiment, since the
20 stacking gap L1 of the stator core 10A is wider than the
stacking gap L2 of the rotor core 50A, the amount of
refrigerant passing through the clearances 102 of the stator
core 10A is increased, and a temperature rise of the winding 2
24 can thereby be suppressed.
[0108]
Regarding the thickness T1 of each electromagnetic steel
sheet 101 of the stator core 10A and the stacking gap L1
28 between the electromagnetic steel sheets 101, and the
thickness T2 of each electromagnetic steel sheet 501 of the
rotor core 50A and the stacking gap L2 between the
electromagnetic steel sheets 501, T1 < T2 and L1 = L2 are
32 satisfied in the first embodiment, whereas T1 = T2 and L1 > L2
are satisfied in the second embodiment. However, the present
disclosure is not limited to these examples, and it is also
30
possible that T1 < T2 and L1 > L2 are both satisfied.
[0109]
THIRD EMBODIMENT
4 Next, a third embodiment will be described. FIG. 16 is
a schematic view illustrating a stator core 10B of a stator 1B
and a rotor core 50B of a rotor 5B according to the third
embodiment. In the third embodiment, an iron loss density of
8 electromagnetic steel sheets 101 of the stator core 10B
measured by an Epstein test is higher than that of
electromagnetic steel sheets 501 of the rotor core 50B.
[0110]
12 In FIG. 16, the thickness T1 of each electromagnetic
steel sheet 101 of the stator core 10B is thinner than the
thickness T2 of each electromagnetic steel sheet 501 of the
rotor core 50B as in the first embodiment. However, the
16 stacking gap L1 of the stator core 10B may be wider than the
stacking gap L2 of the rotor core 50B as described in the
second embodiment, and these relationships may be both
satisfied.
20 [0111]
The Epstein test is defined in JIS_C2550. FIGS. 17(A)
and 17(B) are schematic views for describing the Epstein test.
As illustrated in FIG. 17(A), in the Epstein test, samples 7
24 of electromagnetic steel sheets processed into strip-shapes
are used. Each sample 7 has a width of 30 mm and a length of
280 mm.
[0112]
28 As illustrated in FIG. 17(B), an Epstein tester includes
a spool 65 formed of an insulating resin. The spool 65 is
obtained by combining four spool parts 66, 67, 68, and 69 in a
square shape. Each of the spool parts 66 through 69 has a
32 rectangular cross section and has space therein.
[0113]
Inside the spool parts 66 through 69, the above-
31
mentioned number of samples 7 are inserted in a lattice
pattern to form a magnetic path 70. A coil 6 is wound around
the outer periphery of each of the spool parts 66 through 69.
4 The coil 6 includes an input-side primary coil 61 and a
detection-side secondary coil 62. The number of turns of the
primary coil 61 is equal to the number of turns of the
secondary coil 62.
8 [0114]
Based on a difference between a product of a primary
current and a primary voltage input to the primary coil 61 and
a product of a secondary current and a secondary voltage input
12 to the secondary coil 62, an iron loss of the sample 7 is
measured. An iron loss per a unit weight when a sinusoidal
change in magnetic flux density is induced at a frequency of
50 Hz with a maximum magnetic flux density of 1.5 T is defined
16 as an iron loss density [W/kg].
[0115]
In the third embodiment, an iron loss density W1 of the
electromagnetic steel sheet 101 of the stator core 10B is
20 lower than an iron loss density W2 of the electromagnetic
steel sheet 501 of the rotor core 50B. That is, W1 < W2 is
satisfied. As an example, the iron loss density W1 of the
electromagnetic steel sheet 101 of the stator core 10B is 2.0
24 to 2.5 [W/kg], and the iron loss density W2 of the
electromagnetic steel sheet 501 of the rotor core 50B is 2.5
to 5.0 [W/kg].
[0116]
28 With a configuration in which the iron loss density W1
of the electromagnetic steel sheet 101 of the stator core 10B
is lower than the iron loss density W2 of the electromagnetic
steel sheet 501 of the rotor core 50B, an iron loss occurring
32 in the stator core 10B can be reduced, and a temperature rise
can be suppressed. Accordingly, a temperature rise of
refrigerant passing through the clearances 102 of the stator
32
core 10B is less likely to occur. As a result, heat
dissipation effect of the winding 2 by refrigerant can be
enhanced, and the effect of suppressing a temperature rise of
4 the winding 2 can be enhanced.
[0117]
Such a difference between the iron loss densities W1 and
W2 is obtained by, for example, setting a silicon content S1
8 in the electromagnetic steel sheet 101 larger than a silicon
content S2 in the electromagnetic steel sheet 501 (i.e., S1 >
S2).
[0118]
12 As an example, the silicon content S1 in the
electromagnetic steel sheet 101 of the stator core 10B is 3.5
[wt%], and the silicon content S2 in the electromagnetic steel
sheet 501 of the rotor core 50B is 3.3 [wt%]. Each of the
16 silicon contents S1 and S2 in the electromagnetic steel sheets
101 and 501 is preferably within the range from 2.0 to 7.0%.
[0119]
The silicon contents S1 and S2 in the electromagnetic
20 steel sheets 101 and 501 can be adjusted by selecting the
grade, product-number, or the like of the electromagnetic
steel sheets 101 and 501.
[0120]
24 In general, as the silicon content in electromagnetic
steel sheets increases, an iron loss density measured by the
Epstein test decreases, and an iron loss occurring in the
electromagnetic steel sheets decreases. For this reason, the
28 silicon content S1 in the electromagnetic steel sheet 101 of
the stator core 10B is set larger than the silicon content S2
in the electromagnetic steel sheet 501 of the rotor core 50B,
so that an iron loss occurring in the stator core 10B can be
32 reduced, and a temperature rise can be suppressed.
Accordingly, a temperature rise of refrigerant passing through
the clearances 102 of the stator core 10B is less likely to
33
occur, and as a result, the effect of heat dissipation of the
winding 2 by refrigerant increases, and the effect of
suppressing a temperature rise of the winding 2 can thereby be
4 enhanced.
[0121]
As described above, in the third embodiment, since the
iron loss density W1 of the electromagnetic steel sheets 101
8 of the stator core 10B measured by the Epstein test is lower
than the iron loss density W2 of the electromagnetic steel
sheets 501 of the rotor core 50B measured by the Epstein test,
an iron loss occurring in the stator core 10B is reduced to
12 suppress a temperature rise. Accordingly, it is possible to
enhance the effect of suppressing a temperature rise of the
winding 2 by refrigerant passing through the clearances 102 of
the stator core 10B.
16 [0122]
In addition, since the silicon content S1 in the
electromagnetic steel sheet 101 of the stator core 10B is
larger than the silicon content S2 in the electromagnetic
20 steel sheet 501 of the rotor core 50B, an iron loss occurring
in the stator core 10B can be reduced and a temperature rise
can be suppressed. Accordingly, it is possible to enhance the
effect of suppressing a temperature rise of the winding 2 by
24 refrigerant passing through the clearances 102 of the stator
core 10B.
[0123]
(Compressor)
28 FIG. 18 is a longitudinal sectional view illustrating a
compressor 300 to which the motor of each embodiment is
applicable. The compressor 300 is a rotary compressor, and is
used for, for example, a refrigeration cycle apparatus 400
32 (FIG. 19).
[0124]
FIG. 18 is a sectional view illustrating the compressor
34
300. The compressor 300 is a rotary compressor in this
example, and includes a closed container 307, a compression
mechanism 301 disposed in the closed container 307, and a
4 motor 100 that drives the compression mechanism 301.
[0125]
The compression mechanism 301 includes a cylinder 302
including a cylinder chamber 303, a shaft 4 of the motor 100,
8 a rolling piston 304 fixed to the shaft 4, a vane (not shown)
diving the inside of the cylinder chamber 303 into a suction
side and a compression side, and an upper frame 305 and a
lower frame 306 through which the shaft 4 is inserted and
12 which close end faces of the cylinder chamber 303 in the axial
direction. An upper discharge muffler 308 and a lower
discharge muffler 309 are respectively attached to the upper
frame 305 and the lower frame 306.
16 [0126]
The closed container 307 is a cylindrical container and
includes the shell 8 illustrated in FIG. 1. A bottom portion
of the closed container 307 stores refrigerating machine oil
20 (not shown) for lubricating sliding portions of the
compression mechanism 301. The shaft 4 is rotatably held by
the upper frame 305 and the lower frame 306 serving as bearing
portions.
24 [0127]
The cylinder 302 includes the cylinder chamber 303
therein, and the rolling piston 304 eccentrically rotates in
the cylinder chamber 303. The shaft 4 includes an eccentric
28 shaft part, and the rolling piston 304 is fitted in the
eccentric shaft part.
[0128]
The stator 1 of the motor 100 is incorporated in the
32 shell 8 of the closed container 307 by a method such as shrink
fitting, press fitting, or welding. Electric power is
supplied from a glass terminal 311 fixed to the closed
35
container 307 to the winding 2 of the stator 1. The shaft 4
is fixed to the center hole 54 of the rotor 5.
[0129]
4 An accumulator 310 is attached to the outer side of the
closed container 307. A refrigerant gas flows into the
accumulator 310 from a refrigerant circuit through a suction
pipe 314. In a case where liquid refrigerant flows from the
8 suction pipe 314 together with the refrigerant gas, the liquid
refrigerant is stored in the accumulator 310, and the
refrigerant gas is supplied to the compressor 300.
[0130]
12 A suction pipe 313 is fixed to the closed container 307,
and a refrigerant gas is supplied from the accumulator 310 to
the cylinder 302 through the suction pipe 313. An upper
portion of the closed container 307 includes a discharge pipe
16 312 for discharging refrigerant to the outside.
[0131]
As refrigerant in the compressor 300, R410A, R407C, R22
or the like may be used, for example. However, from the
20 viewpoint of preventing global warming, refrigerant having a
low global warming potential (GWP) is preferably used. As the
low-GWP refrigerant, the following refrigerants can be used,
for example.
24 [0132]
(1) First, halogenated hydrocarbon having a double bond
of carbon in its composition, such as hydro-fluoro-olefin
(HFO)-1234yf (CF3CF=CH2) can be used. HFO-1234yf has a GWP of
28 4.
(2) Further, hydrocarbon having a double bond of carbon
in its composition, such as R1270 (propylene), may be used.
R1270 has a GWP of 3, which is smaller than that of HFO-1234yf,
32 but has flammability higher than that of HFO-1234yf.
(3) A mixture containing at least one of halogenated
hydrocarbon having a double bond of carbon in its composition
36
or hydrocarbon having a double bond of carbon in its
composition, such as a mixture of HFO-1234yf and R32, may be
used. Since HFO-1234yf described above is a low-pressure
4 refrigerant, a pressure loss tends to increase, and
performance of a refrigeration cycle (especially an
evaporator) may degrade. Thus, it is practically preferable
to use a mixture with R32 or R41, which is a higher-pressure
8 refrigerant than HFO-1234yf.
[0133]
Operation of the compressor 300 is as follows. A
refrigerant gas supplied from the accumulator 310 passes
12 through the suction pipe 313, and is supplied to the cylinder
chamber 303 of the cylinder 302. When the motor 100 is driven
by supplying a current to the winding 2, the shaft 4 rotates
together with the rotor 5. Then, the rolling piston 304
16 fitted in the shaft 4 eccentrically rotates in the cylinder
chamber 303, and refrigerant is compressed in the cylinder
chamber 303.
[0134]
20 The refrigerant compressed in the cylinder chamber 303
passes through the discharge mufflers 308 and 309, and further
passes through the through holes 56 and 57 of the rotor 5 (FIG.
1) and the through holes 16 and the recesses 19 of the stator
24 1 (FIG. 3) and rises in the closed container 307. The
refrigerant that has risen in the closed container 307 is
discharged through the discharge pipe 312 and supplied to a
high-pressure side of the refrigeration cycle.
28 [0135]
Although refrigerating machine oil is mixed in the
refrigerant compressed in the cylinder chamber 303, separation
of the refrigerant and the refrigerant machine oil is promoted
32 while the refrigerant passes through the through holes 56 and
57 of the rotor 5 or the through holes 16 and the recesses 19
of the stator 1, and an inflow of the refrigerating machine
37
oil into the discharge pipe 312 is prevented.
[0136]
The motor 100 described in each of the embodiments can
4 suppress a temperature rise of the winding 2, and thus, high
reliability of the compressor 300 can be obtained for a long
period of time.
[0137]
8 (Refrigeration Cycle Apparatus)
The refrigeration cycle apparatus 400 to which the motor
of each embodiment is applicable will now be described. FIG.
19 is a view illustrating a configuration of the refrigeration
12 cycle apparatus 400. The refrigeration cycle apparatus 400 is
an air conditioner in this example, but may be a refrigerator
or the like.
[0138]
16 The refrigeration cycle apparatus 400 includes the
compressor 300, a four-way valve 401 as a switching valve, a
condenser 402 that condenses refrigerant, a decompressor 403
that decompresses refrigerant, and an evaporator 404 that
20 vaporizes refrigerant.
[0139]
The compressor 300, the condenser 402, the decompressor
403, and the evaporator 404 are coupled by a refrigerant pipe
24 407, and constitute a refrigerant circuit. The compressor 300
includes an outdoor fan 405 facing the condenser 402, and an
indoor fan 406 facing the evaporator 404.
[0140]
28 Operation of the refrigeration cycle apparatus 400 is as
follows. The compressor 300 compresses sucked refrigerant and
sends out the compressed refrigerant as a high-temperature and
high-pressure refrigerant gas. The four-way valve 401 is
32 configured to switch a flow direction of refrigerant, and in a
cooling operation, causes the refrigerant sent from the
compressor 300 to flow to the condenser 402, as indicated by
38
solid lines in FIG. 19.
[0141]
The condenser 402 performs heat exchange between the
4 refrigerant sent from the compressor 300 and outdoor air sent
by the outdoor fan 405, condenses the refrigerant, and sends
out the condensed refrigerant as liquid refrigerant. The
decompressor 403 expands the liquid refrigerant sent from the
8 condenser 402, and sends out the expanded refrigerant as lowtemperature and low-pressure liquid refrigerant.
[0142]
The evaporator 404 performs heat exchange between indoor
12 air and the low-temperature and low-pressure liquid
refrigerant sent from the decompressor 403, evaporates the
refrigerant, and sends out the refrigerant as a refrigerant
gas. Air from which heat has been taken by the evaporator 404
16 is supplied by the indoor fan 406 into a room.
[0143]
In a heating operation, the four-way valve 401 sends out
the refrigerant sent from the compressor 300 to the evaporator
20 404. In this case, the evaporator 404 functions as a
condenser, and the condenser 402 functions as an evaporator.
[0144]
The motor 100 described in each of the first through
24 third embodiments is included as a driving source of the
compressor 300, and thus reliability of the refrigeration
cycle apparatus 400 can be enhanced. The compressor including
one of the motors 100 according to the first through third
28 embodiments is also appliable to another refrigeration cycle
apparatus.
[0145]
Although the preferred embodiments have been
32 specifically described above, the present disclosure is not
limited to these embodiments, and various improvements and
modifications may be made.
39
DESCRIPTION OF REFERENCE CHARACTERS
[0146]
1, 1A, 1B, 1C stator, 2 winding, 3 insulating portion, 4
4 shaft, 5, 5A, 5B rotor, 8 shell, 9 split core, 10, 10A, 10B
stator core, 11 yoke, 12 tooth, 12a tooth tip, 13 slot, 16
through hole, 17 crimping portion (round crimping), 18
crimping portion (V-crimping), 19 recess, 31 insulator, 50,
8 50A, 50B rotor core, 51 magnet insertion hole, 52 flux barrier,
53 bridge, 55 permanent magnet, 100 motor, 101 electromagnetic
steel sheet, 102 stacking gap, 300 compressor, 301 compression
mechanism, 302 cylinder, 307 closed container, 400
12 refrigeration cycle apparatus, 401 four-way valve, 402
condenser, 403 decompressor, 404 evaporator, 501
electromagnetic steel sheet, 502 stacking gap

WE CLAIM:
Claim 1.
4 A motor comprising:
a rotor comprising a rotor core having an annular shape
about an axis and formed of electromagnetic steel sheets
stacked in a direction of the axis, the rotor comprising a
8 permanent magnet attached to the rotor core; and
a stator comprising a stator core surrounding the rotor
core and formed of electromagnetic steel sheets stacked in the
direction of the axis, the stator comprising a winding wound
12 on the stator core and formed of an aluminum wire,
wherein a stacking factor O1 of the electromagnetic
steel sheets of the stator core and a stacking factor O2 of
the electromagnetic steel sheets of the rotor core satisfy:
16 O1 < O2.
Claim 2.
The motor according to claim 1, wherein a thickness T1
20 of each of the electromagnetic steel sheets of the stator core
and a thickness T2 of each of the electromagnetic steel sheets
of the rotor core satisfy:
T1 < T2.
24
Claim 3.
The motor according to claim 1 or 2, wherein a thickness
T1 of each of the electromagnetic steel sheets of the stator
28 core and a thickness T2 of each of the electromagnetic steel
sheets of the rotor core satisfy:
T1 < T2 < 4 × T1.
32 Claim 4.
The motor according to any one of claims 1 to 3, wherein
the rotor core has a magnet insertion hole in which the
41
permanent magnet is disposed, and a bridge located between the
magnet insertion hole and the rotor core,
wherein the bridge has a width W in a radial direction
4 about the axis, and
wherein the width W and the thickness T1 of each of the
electromagnetic steel sheets of the stator core satisfy:
W < T1.
8
Claim 5.
The motor according to any one of claims 1 to 4, wherein
a gap L1 between the electromagnetic steel sheets of the
12 stator core and a gap L2 between the electromagnetic steel
sheets of the rotor core satisfy:
L1 > L2.
16 Claim 6.
The motor according to any one of claims 1 to 5, wherein
when a sinusoidal change in magnetic flux density is induced
at a frequency of 50 Hz with a maximum magnetic flux density
20 of 1.5 T in an Epstein test, an iron loss density W1 per a
unit weight of the electromagnetic steel sheets of the stator
core and an iron loss density W2 per a unit weight of the
electromagnetic steel sheets of the rotor core satisfy:
24 W1 < W2.
Claim 7.
The motor according to any one of claims 1 to 6, wherein
28 a silicon content S1 in the electromagnetic steel sheets of
the stator core and a silicon content S2 in the
electromagnetic steel sheets of the rotor core satisfy:
S1 > S2.
32
Claim 8.
The motor according to any one of claims 1 to 7, wherein
42
the stator core has a through hole formed from one end to the
other end of the stator core in an axial direction.
4 Claim 9.
The motor according to claim 8, wherein the stator core
comprises a yoke having an annular shape about the axis, and a
tooth extending from the yoke toward the axis, and
8 wherein the through hole is formed in the yoke.
Claim 10.
The motor according to claim 8 or 9, wherein the winding
12 is wound on the stator core via an insulating portion, and
wherein the through hole is exposed at an end face of
the stator core in a direction of the axis and is not covered
with the insulating portion.
16
Claim 11.
The motor according to any one of claims 1 to 10,
wherein the stator core is fixed to an inner side of a shell
20 of a compressor, and
wherein a recess is formed on an outer periphery of the
stator core, the recess forming a refrigerant passage between
the outer periphery of the stator core and an inner peripheral
24 surface of the shell.
Claim 12.
The motor according to any one of claims 1 to 11,
28 wherein the stator core comprises a yoke having an annular
shape about the axis, and a tooth extending from the yoke
toward the axis, and
wherein the winding is wound around the tooth by salient
32 pole concentrated winding.
Claim 13.
43
The motor according to claim 12, wherein the winding is
wound around the tooth by regular winding.
4 Claim 14.
The motor according to any one of claims 1 to 13,
wherein the stator core has a plurality of split cores
combined in an annular shape.
8
Claim 15.
A compressor comprising:
the motor according to any one of claims 1 to 14; and
12 a compression mechanism driven by the motor.
Claim 16.
A refrigeration cycle apparatus comprising:
16 the compressor according to claim 15, a condenser, a
decompressor, and an evaporator