FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
[See section 10, Rule 13]
ELECTRIC 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 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 disclosure relates to an electric motor, a compressor and a
refrigeration cycle apparatus. In particular, it relates to rotors and the like of
permanent-magnet embedded type electric motors.
Background Art
10 [0002]
Conventionally, permanent-magnet embedded electric motors are known, in
which permanent magnets are placed in magnet insertion holes in the rotor. In some
rotors of permanent-magnet-embedded type motors, permanent magnets are
embedded so that they penetrate the laminated iron core in the axial direction. Here,
15 when the axial length of the permanent magnet is long, excessive eddy currents are
generated on the surface of the permanent magnet, which can reduce the efficiency
of the electric motor.
[0003]
Therefore, in a rotor of a permanent-magnet embedded electric motor in which
20 a magnet is placed in a magnet insertion hole provided in a rotor, the rotor is provided
with a plurality of rotor members divided in the axial direction having the magnet
insertion hole and a partition plate disposed between the respective rotor members,
and the plurality of rotor members and the partition plate are stacked in the axial
direction to form a single unit. The plurality of rotor members and the partition plates
25 are stacked in the axial direction to form a rotor of a permanent-magnet embedded
type electric motor (see, for example, Patent Literature 1).
[0004]
This rotor is composed of three rotor members divided in the axial direction and
a separator that serves as a divider plate. The rotor members are formed by
30 lamination of electromagnetic steel sheets in a circular shape. Near the outer
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3
periphery of the rotor members, magnet holes are formed along the axial direction to
install magnets with opening ports on the sides of the rotor members. The separator,
on the other hand, is coated with an insulating layer and separates each rotor
member from the other. The separator is made of electromagnetic steel sheet,
which is circular and thin like the rotor members. The rotor body 5 is composed of
rotor members and separators stacked in the axial direction, with separators between
each rotor member, and integrally coupled. Here, the inner and outer circumferential
edges of the separator are uniformly disposed on the inner and outer circumferential
surfaces of the rotor member, respectively.
10 [0005]
To suppress centrifugal expansion or deformation of the iron core at the center
in the axial direction of the rotor, there is a rotor having an iron core in which a
plurality of magnet insertion holes are formed into which magnets are inserted, and
end plates arranged on both sides of the iron core and fixed to the shaft together with
15 the iron core to block magnetic flux. In the rotor, a disk-shaped separator without
magnet insertion holes is placed in the middle of the length direction of the iron core,
and this separator is bonded to at least the end face of each magnet (see, for
example, Patent Literature 2).
[0006]
20 In this rotor, one disk-shaped end plate made of a non-magnetic material is
inserted and fixed to the shaft, and then a pair of half iron cores made of thin steel
sheet laminates are inserted into the shaft to sandwich the separator. The other end
plate made of non-magnetic material is also inserted into the shaft and fixed. With
the pair of end plates, the pair of half iron cores and the separator are pressure25
tightened. In other words, the iron core is formed with a pair of half iron cores.
Here, the separator can be of any type, magnetic or non-magnetic.
Citation List
Patent Literature
[0007]
30 Patent Literature 1: JP2006-158037A
.
4
Patent Literature 2: JP2002-191143A
Summary of Invention
Technical Problem
[0008]
However, in the rotor in the electric motor of Patent Literature 5 1, the separator
that separates the rotor members is coated with an insulating layer, but the structure
allows contact between the magnet and the separator. As a result, leakage flux from
the magnet to the separator is generated. In Patent Literature 1, a measure is taken
that installs an opening port in the separator to reduce the leakage flux, but this is not
10 a sufficient anti-leakage flux measure.
[0009]
In the rotor structure of the electric motor in Patent Literature 2, the separator
for separating the rotor members is bonded to the end surface of the magnet in both
magnetic and non-magnetic materials. As a result, leakage flux from the magnet to
15 the separator is generated. Therefore, the countermeasure against surface eddy
current loss of the magnet is not sufficient.
[0010]
The electric motor, the compressor and the refrigeration cycle apparatus of the
present disclosure aims to provide an electric motor, a compressor and a refrigeration
20 cycle apparatus that reduces the surface eddy current loss generated on the surface
of the permanent magnet in order to solve the above problems.
Solution to Problem
[0011]
The electric motor according to this disclosure is an electric motor having a
25 stator and a rotor, the rotor comprising: a shaft being a rotation axis; and an iron core
fixed to the shaft and including a first iron core group having a magnet insertion hole
into which a permanent magnet that generates magnetic flux is inserted; and a
second iron core group having a through hole that is connected to the magnet
insertion hole and is formed in a shape that prevents the passage of the permanent
30 magnet, and an end plate covering each of the two end faces of the iron core.
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5
[0012]
A compressor of the present disclosure includes a sealed container that serves
as an outer shell; a compression mechanism unit installed in the sealed container that
compresses and discharges the refrigerant to the outside; and the above-stated
electric motor that supplies power to the compression 5 mechanism unit.
[0013]
A refrigeration cycle apparatus of the present disclosure includes a refrigeration
cycle apparatus having a refrigerant circuit in which the above-stated compressor, a
condenser, a pressure reducing device, and an evaporator are connected by pipes
10 and in which refrigerant is circulated.
Advantageous Effects of Invention
[0014]
According to the embodiments of the present disclosure, in the rotor of an
electric motor, the permanent magnets inserted in the magnet insertion holes of each
15 first iron core group are separated and provided by a second iron core group having
through holes formed in a shape that prevents the permanent magnets from passing
through. This increases the magnetic resistance of the permanent magnet and
suppresses eddy currents generated on the surface of the permanent magnet.
Therefore, the device efficiency can be increased.
20 Brief Description of Drawings
[0015]
[Fig. 1] Fig. 1 illustrates the inner configuration of an electric motor 1 according
to Embodiment 1 of the present disclosure.
[Fig. 2] Fig. 2 illustrates the configuration of a rotor 10 of the motor 1 according
25 to Embodiment 1 of the present disclosure.
[Fig. 3] Fig. 3 illustrates a form of a second iron core group 11b in an iron core
11 according to Embodiment 1 of the present disclosure.
[Fig. 4] Fig. 4 illustrates the relationship between a permanent magnet 13 and
convex portion 15 according to Embodiment 1 of the present disclosure.
.
6
[Fig. 5] Fig. 5 illustrates advantageous effects obtained with the configuration of
the rotor 10 of the motor 1 according to Embodiment 1 of the present disclosure.
[Fig. 6] Fig. 6 illustrates the configuration of a rotor 10 of an electric motor 1
according to Embodiment 2 of the present disclosure.
[Fig. 7] Fig. 7 illustrates the configuration of a compressor 5 110 including the
motor 1 according to Embodiment 2 of the present disclosure.
[Fig. 8] Fig. 8 illustrates a configuration example of a refrigeration cycle
apparatus according to Embodiment 3 of the present disclosure.
Description of Embodiments
10 [0016]
The following describes the embodiments of the disclosure with reference to
the drawings and the like. In the drawings, items marked with the same reference
signs are the same or equivalent and will be common in the full text of the
embodiments described below. The forms of the elements represented in the entire
15 specification are only examples, and are not limited to the forms described in the
specification. In particular, the combination of components is not limited only to the
combination in each embodiment, and the components described in other
embodiments can be applied to other embodiments. The upper part in the figure is
described as the "upper side" and the lower part as the "lower side". And in the
20 drawings, the relationship between the sizes of each component may differ from the
actual ones.
[0017]
Embodiment 1
Fig. 1 illustrates the configuration inside the electric motor 1 according to
25 Embodiment 1 of the disclosure. In Fig. 1, the electric motor 1 is viewed from the
front side. In Embodiment 1, an electric motor 1 with an embedded permanent
magnet is described. The electric motor 1 has a stator 20 and a rotor 10. The
stator 20 has a plurality of teeth 21 and windings 22. In the stator 20, a plurality of
teeth 21 are arranged in a circumferential direction, forming a circular shape. Each
30 of the teeth 21 is wound with a windings 22. On the inner side of the stator 20 in the
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radial direction, a circular rotor 10 is disposed opposite the teeth 21 and is rotatable in
the circumferential direction.
[0018]
Fig. 2 shows the configuration of the rotor 10 of the electric motor 1 according
to the embodiment 1 of the present disclosure. As shown in Fig. 5 2, the rotor 10 of
embodiment 1 has an iron core 11, a shaft 12, a plurality of permanent magnets 13,
and end plates 16. The shaft 12 serves as the axis of rotation when it rotates. The
iron core 11 is fixed to the shaft 12. The iron core 11 of Embodiment 1 has a first
iron core group 11a and a second iron core group 11b that are divided into a plurality
10 of groups in the direction of the rotation axis. The iron core 11 of Embodiment 1 has
three first iron core groups 11a and two second iron core groups 11b, with the second
iron core group 11b sandwiched between the two first iron core groups 11a.
[0019]
The first iron core group 11a is composed of a laminated body of thin disc15
shaped electromagnetic steel plates. Therefore, the first iron core group 11a has a
cylindrical shape. Each electromagnetic steel plate in the first iron core group 11a
has a plurality of through slits corresponding to the rotational direction in the portion
near the cylindrical outer peripheral surface. In the laminated body in which the
electromagnetic steel plates are stacked, the slits form magnet insertion holes 14a.
20 In each magnet insertion hole 14a, a permanent magnet 13 is inserted. The
permanent magnet 13 is made of rare earth or ferrite. The permanent magnet 13
generates a magnetic field by magnetic force such that the magnetic flux is directed
to the outer circumference of the rotor 10.
[0020]
25 Fig. 3 illustrates the configuration of the second iron core group 11b in the iron
core 11 of Embodiment 1 of the present disclosure. The second iron core group 11b
has a through hole 14b at a position that corresponds to and connects with the
magnet insertion hole 14a of the first iron core group 11a. The second iron core
group 11b has at least one convex portion 15 in the through hole 14b portion. In the
30 second iron core group 11b, the convex portion 15 protrudes into the space of the
.
8
through hole 14b, thereby narrowing the distance of the space in the through hole 14b
where the convex portion 15 is provided, and forming the through hole 14b into a
shape that prevents the passage of the permanent magnet 13. Therefore, the
convex portion 15 functions as a stopper to prevent the permanent magnet 13
inserted in the magnet insertion hole 14a from passing through the 5 through hole 14b.
As a result, the permanent magnets 13 in the iron cores 11 are separated and placed
in the magnet insertion holes 14a of each first iron core group 11a. Here, from the
viewpoint of preventing magnetic path formation, the convex portion 15 that is part of
the electromagnetic steel plate should be as small as possible.
10 [0021]
As shown in Fig. 4 below, the distance d of the through hole 14b in the radial
direction of the shaft 12, which is the axis of rotation of the portion of the through hole
14b where the convex portion 15 is provided, should be greater than or equal to the
air gap G between the stator 20 and the rotor 10. For example, the distance d
15 should be at least two times and no more than three times the air gap G. As a result,
the rotor 10 of Embodiment 1 is not hindered by the convex portion 15 from the
magnetic flux chained to the windings 22.
[0022]
As shown in Fig. 3, the second iron core group 11b of embodiment 1 has three
20 convex portions 15. The three convex portions 15 are provided at unopposed
positions in the horizontal direction, which is the radial direction of the shaft 12, which
is the axis of rotation. Here, in the iron core 11 of the rotor 10 of Embodiment 1, the
number of electromagnetic steel plates constituting the second iron core group 11b is
assumed to be one. However, it may be composed of a laminated body in which a
25 plurality of electromagnetic steel plates are laminated.
[0023]
End plates 16 are installed at both ends of the iron core 11. The end plates 16
block the magnetic flux generated by the permanent magnets 13.
[0024]
30 Fig. 4 illustrates the relationship between the permanent magnet 13 and the
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9
convex portion 15 in accordance with Embodiment 1 of the present disclosure. In
Fig. 4, the positional relationship between the permanent magnet 13 inserted into the
magnet insertion hole 14a and the plurality of convex portions 15 is shown. The
permanent magnet 13 inserted into the magnet insertion hole 14a is engaged by the
convex portion 15 and prevented from passing through the through 5 hole 14b. Here,
there is a gap between the magnet insertion hole 14a and the permanent magnet 13,
and the permanent magnet 13 in the magnet insertion hole 14a is tilted in the magnet
insertion hole 14a because the entire bottom surface is not supported. As a result of
the tilt of the permanent magnet 13, a part of the permanent magnet 13 protrudes into
10 the space created by the through hole 14b.
[0025]
As shown in Fig. 4, the length of the magnet insertion hole 14a in the rotational
axis direction is L, and the length of the permanent magnet 13 in the rotational axis
direction is l. Also, the thickness of the permanent magnet 13 is T. The length of
15 the convex portion 15 in the direction of the rotation axis is y, and the maximum tilt
angle at which the permanent magnet 13 is tilted by the convex portion 15 is θ. At
this time, the plurality of convex portions 15 that the second iron core group 11b of
Embodiment 1 has are formed so that the relationship l x cosθ + T x sinθ < l + y holds.
Therefore, even if a part of the permanent magnets 13 in the magnet insertion holes
20 14a in the first iron core group 11a on both sides of the second iron core group 11b
protrude into the space of the through holes 14b, respectively, the permanent
magnets 13 do not physically contact each other.
[0026]
Thus, according to the rotor 10 of the electric motor 1 in the embodiment 1, the
25 permanent magnets 13 inserted into the magnet insertion holes 14a of each magnetinsertable
first iron core group 11a are separated by the convex portion 15 of the
second iron core group 11b. As a result, the magnetic resistance of the permanent
magnets 13 increases, and the eddy currents generated on the surface of the
permanent magnets 13 can be suppressed. Therefore, a high-efficiency electric
30 motor 1 can be obtained.
.
10
[0027]
When the second iron core group 11b has a plurality of convex portions 15,
each of the plurality of convex portions 15 is disposed at an unopposed position in the
radial direction of the shaft 12, which is the axis of rotation. Therefore, the convex
portions 15 do not face each other to narrow the space of the through 5 hole 14b, and it
is difficult for the convex portions 15 to form a magnetic path with each other, thereby
suppressing the generation of leakage magnetic flux. Therefore, the efficiency of the
electric motor 1 can be further increased.
[0028]
10 In addition, by ensuring that the distance d in the radial direction of the shaft 12
of the portion of the through hole 14b in which the convex portion 15 is provided is a
distance greater than or equal to the air gap G between the stator 20 and the rotor 10,
the magnetic flux chained to the windings 22 can be unobstructed. Therefore, the
efficiency of the electric motor 1 can be further increased.
15 [0029]
Further, the second iron core group 11b of the embodiment 1 includes the
convex portion 15 that satisfies the relationship l x cosθ + T x sinθ < L + y for the
rotational axial length L of the magnet insertion hole 14a, the rotational axial length l
and thickness T of the permanent magnet 13, the maximum tilt angle θ of the
20 permanent magnet 13 in the magnet insertion hole 14a, and the rotational axial length
y of the convex portion 15. As a result, physical contact between permanent
magnets 13 contained respectively in adjacent first iron core groups 11a can be
avoided. As mentioned above, the smaller the convex portion 15 is, the better. By
forming the convex portion 15 in a small size while satisfying the above-described
25 relationship, the generation of eddy currents on the surface of the permanent
magnets 13 can be suppressed and damage such as cracking of the permanent
magnets 13 can be prevented.
[0030]
Fig. 5 illustrates the effect obtained by the configuration of the rotor 10 of the
30 electric motor 1 according to the embodiment 1 of the present disclosure. In Fig. 5,
.
11
(a) represents the torque and surface eddy current loss of the permanent magnet of a
conventional rotor configured without dividing the iron core and magnet. And (b)
represents the torque and surface eddy current loss of the permanent magnet of a
conventional rotor that does not have a through hole 14b like the rotor 10 of
Embodiment 1 and is composed of two parts. And (c) represents 5 the torque and the
surface eddy current loss of the permanent magnet of the rotor 10 of the embodiment
1. As shown in Fig. 5, the rotor of Embodiment 1 can suppress the surface eddy
current loss of the permanent magnets while maintaining the same torque as the
conventional rotor.
10 [0031]
Embodiment 2
Fig. 6 shows the configuration of the rotor 10 of the electric motor 1 according
to embodiment 2 of the present disclosure. In Fig. 6, parts and materials with the
same sign as in Fig. 1, etc. are equivalent to those described in Embodiment 1. In
15 the rotor 10 of Embodiment 2, the first iron core group 11a, in which a magnet
insertion hole 14a is provided in which a permanent magnet 13 is inserted, is
arranged on one end face side. Then, on the other end face side, a second iron
core group 11b is arranged with a through hole 14b in which the passage of the
permanent magnet 13 is blocked by the convex portion 15 described in Embodiment
20 1. Then, end plates 16 are arranged on both end faces and integrated into a single
unit. Here, it is assumed that the electric motor 1 of Embodiment 2 is mounted in a
compressor that compresses and discharges the refrigerant in a refrigeration cycle
apparatus.
[0032]
25 Fig. 7 illustrates the configuration of a compressor 110 equipped with an
electric motor 1 according to Embodiment 2 of the present disclosure. In the
compressor 110, the shell 111, which serves as the outer shell, is a sealed container
that houses the electric motor 1, the compression mechanism unit 113, etc. inside.
The suction pipe 112 is installed in the shell 111. The suction pipe112 is a pipe that
30 leads the refrigerant to be compressed, which is suctioned from the suction muffler
.
12
116, into the shell 111. The compression mechanism unit 113 includes a
compression chamber formed by combining a fixed scroll and an orbiting scroll. The
orbiting scroll is connected to the main shaft 114, which is rotated by the electric
motor 1 mounted in the compressor 110, and rotates with the rotation of the main
shaft 114 to receive power supply and compress the refrigerant 5 flowing into the
compression chamber. The discharge pipe 115 is the pipe through which the
compressed refrigerant is discharged. The driver 117 is electrically connected to the
electric motor 1 in the compressor 110, supplies electric power to the motor 1, and
controls the drive of the compressor 110.
10 [0033]
The permanent magnet 13 in the rotor 10 of the electric motor 1 in Embodiment
2 will now be described. In general, a magnet with a strong magnetic force is
cheaper than a magnet with a weak magnetic force. For this reason, we consider
using a magnet with high magnetic force for the permanent magnet 13 to reduce the
15 cost. In order to maintain the same level of magnetic field generation as before even
when a magnet with high magnetic force is used for the permanent magnet 13, the
volume of the permanent magnet 13 inserted into the magnet insertion hole 14a is
reduced. At this time, in consideration of the diversion of the core type of the rotor
10, a method to reduce the volume of the permanent magnet 13 is generally adopted
20 by shortening the dimensions of the permanent magnet 13 in the direction of the
rotation axis.
[0034]
However, if the rotational axial dimensions of the stator 20 and rotor 10 are
reduced in accordance with the reduction of the rotational axial dimensions of the
25 permanent magnets 13, the resistance and inductance of the windings 22, which are
the control constants of the electric motor 1, are changed. As a result, it becomes
impossible to use the conventional driver that was designed based on the rotational
axial dimension in the rotor.
[0035]
30 On the other hand, if the rotational axial dimension of the rotor 10 is not
.
13
changed, but only the permanent magnet 13 and the rotational axial dimension are
shortened, the maximum value of the magnetic thrust generated by the misalignment
between the magnetic center of the permanent magnet 13 and the center of the stator
20 will increase and the minimum value will decrease. Therefore, for example, when
used as an electric motor for a compressor, an increase in magnetic 5 thrust will
increase the frictional force of the compression mechanism units. Also, when the
magnetic thrust decreases, the vibration of the components of compression
mechanism unit in the direction of the rotation axis increases.
[0036]
10 Therefore, in the electric motor 1 of Embodiment 2, the magnetic thrust force
generated by the gap between the magnetic center of the permanent magnet 13 and
the center of the stator 20 is adjusted by changing the length of the first iron core
group 11a, the permanent magnet 13, and the second iron core group 11b. More
specifically, the rotational axial dimension of the first iron core group 11a, which has a
15 magnet insertion hole 14a into which the permanent magnet 13 is inserted, is
specified in accordance with the rotational axial dimension of the permanent magnet
13, which has been shortened with increase of the magnetic force. Then, the
rotational axial dimension of the second iron core group 11b having the through hole
14b into which the permanent magnet 13 is not inserted is specified so that the
20 rotational axial dimension by the first iron core group 11a and the second iron core
group 11b becomes the rotational axial dimension of the iron core in a conventional
rotor. Therefore, the overall length in the rotational axis direction in the iron core 11
of the rotor 10 is not different from that of a conventional rotor. Therefore, a
conventional driver can be used in the compressor.
25 [0037]
As described above, according to the rotor 10 of the electric motor 1 of
Embodiment 2, the rotational axial length in the first iron core group 11a and the
second iron core group 11b is adjusted and specified in accordance with the rotational
axial length of the permanent magnet 13. Therefore, the rotational axial dimension
30 of the iron core 11 can be the same as that of a conventional rotor. Therefore, the
.
14
driver used for the conventional compressor can be diverted. In addition, since a
magnet with strong magnetic force can be used for the permanent magnet 13, the
cost of the rotor 10 and the electric motor 1 can be reduced.
[0038]
5 Embodiment 3
Fig. 8 shows an example of a configuration of a refrigeration cycle apparatus
according to Embodiment 3 of the present disclosure. Fig. 8 shows an airconditioning
apparatus as a refrigeration cycle apparatus. The air-conditioning
apparatus shown in Fig. 8 connects the outdoor unit 100 and the indoor unit 200 by
10 pipes with a gas refrigerant pipe 300 and a liquid refrigerant pipe 400 to form a
refrigerant circuit that circulates refrigerant. The outdoor unit 100 is connected to the
indoor unit 200 by a gas refrigerant pipe 300 and a liquid refrigerant pipe 400 to form
a refrigerant circuit. The outdoor unit 100 has a compressor 110, four-way valve 120,
outdoor heat exchanger 130, expansion valve 140, and outdoor fan 150. The indoor
15 unit 200 has an indoor heat exchanger 210 and an indoor fan 220.
[0039]
The compressor 110 includes the electric motor 1 described in Embodiment 1
or Embodiment 2. The compressor 110 compresses refrigerant that has been
sucked and discharges the refrigerant. Here, regarding the compressor 110, the
20 driving frequency thereof can be changed appropriately by using, for example, the
driver 117 described in Embodiment 2.
[0040]
The four-way valve 120 is a valve that switches the flow of refrigerant
depending on whether it is in cooling operation or heating operation. The outdoor
25 heat exchanger 130 performs heat exchange between the refrigerant and the outdoor
air. For example, during heating operation, it functions as an evaporator to
evaporate and vaporize the refrigerant. For example, during heating operation, it
functions as an evaporator to evaporate and vaporize the refrigerant, and during
cooling operation, it functions as a condenser to condense and liquefy the refrigerant.
30 Then, the outdoor fan 150 sends outdoor air to the outdoor heat exchanger 130.
.
15
[0041]
The expansion valve 140, such as an aperture device (flow control unit), which
serves as a pressure reducing device, reduces the pressure of the refrigerant and
expands it. The expansion valve 140, for example, when configured with an
electronic expansion valve, performs opening degree adjustment 5 based on
instructions from a control unit (not shown) or other device. The indoor heat
exchanger 210, for example, exchanges heat between the air to be conditioned and
the refrigerant. During heating operation, it functions as a condenser to condense
and liquefy the refrigerant. It also functions as an evaporator during cooling
10 operation to evaporate and vaporize the refrigerant. Then, the indoor fan 220 sends
the air to be conditioned to the indoor heat exchanger 210.
[0042]
As described above, according to the refrigeration cycle apparatus of
Embodiment 3, since the compressor 110 having the electric motor 1 described in
15 Embodiment 1 and Embodiment 2 is possessed as a device, the apparatus as a
whole can be operated efficiently. In particular, as explained in Embodiment 2, the
length in the direction of the rotation axis in the first and second iron core groups 11a
and 11b can be adjusted to be the same as the length in the direction of the rotation
axis in the iron core of a conventional rotor. Therefore, the driver 117 in the
20 compressor 110 can be used and the cost of the compressor 110 can be reduced.
Reference Signs List
[0043]
1 electric motor, 10 rotor, 11 iron core, 11a first iron core group, 11b second iron
25 core group, 12 shaft, 13 permanent magnet, 14a magnet insertion hole, 14b through
hole, 15 convex portion, 16 end plate, 20 stator, 21 teeth, 22 windings, 100 outdoor
unit, 110 compressor, 111 shell, 112 suction pipe, 113 compression mechanism unit,
114 main shaft, 115 discharge pipe, 116 suction muffler, 117 driver, 120 four-way
valve, 130 outdoor heat exchanger, 140 expansion valve, 150 outdoor fan, 200 indoor
30 unit, 210 indoor heat exchanger, 220 indoor fan, 300 gas refrigerant pipe, 400 liquid
.
16
refrigerant pipe.
.
17
We Claim :
[Claim 1]
An electric motor having a stator and a rotor, the rotor comprising:
a shaft being a rotation axis; and
an iron core fixed to the shaft 5 and including
a first iron core group having a magnet insertion hole into which a
permanent magnet that generates magnetic flux is inserted; and
a second iron core group having a through hole that is connected to the
magnet insertion hole and is formed in a shape that prevents the passage of the
10 permanent magnet, and
an end plate covering each of the two end faces of the iron core.
[Claim 2]
The electric motor of claim 1, wherein the second iron core group has a
plurality of convex portions projecting toward space of the through hole in the radial
15 direction of the shaft, and the plurality of the convex portions are provided at positions
in the radial direction of the shaft of the through hole, the positions being positions
within the through hole at which the convex portions do not face each other in the
radial direction of the shaft.
[Claim 3]
20 The electric motor of claim 1 or 2, wherein
the second iron core group has convex portions projecting toward the space of
the through hole in the radial direction of the shaft, and wherein
the convex portion has a relationship:
l x cosθ + T x sinθ < L + y
25 where
a length of the magnet insertion hole in a rotational axis direction is L,
a length of the permanent magnet in the rotational axis direction is l,
a thickness of the permanent magnet is T,
a length of the convex portion in the rotational axis direction is y, and
30 a maximum tilt angle of the permanent magnet in the magnet insertion hole is θ.
.
18
[Claim 4]
An electric motor of claim 2 or 3, wherein the distance in the radial direction of
the shaft within the through hole in the portion where the convex portion is provided is
longer than the distance between the stator and the rotor.
5 [Claim 5]
A compressor comprising:
a sealed container that serves as an outer shell;
a compression mechanism unit installed in the sealed container and configured
to compress and discharge the refrigerant to the outside; and
10 an electric motor of any one of claims 1 to 4 that supplies power to the
compression mechanism unit.
[Claim 6]
A refrigeration cycle apparatus having a refrigerant circuit in which the
compressor of claim 5, a condenser, a pressure reducing device, and an evaporator
15 are connected by pipes and in which refrigerant is circulated.