Description Title of Invention: ELECTRIC MOTOR, COMPRESSOR, REFRIGERATING CYCLE APPARATUS, AND METHOD OF MANUFACTURING ELECTRIC MOTOR
Technical Field
[0001] The present invention relates to an electric motor, a compressor, a
refrigerating cycle apparatus, and a method of manufacturing an electric motor.
Background Art
[0002] As a technology of joining electric wires of an electric motor, one is available that joins a copper wire and an aluminum wire wound around the copper wire to each other with a brazing material (see, for example, Patent Literature 1).
Citation List
Patent Literature
[0003] Patent Literature 1: JP 2015-216728 A
Summary of Invention Technical Problem
[0004] According to the conventional technology, when two or more copper wires and an aluminum wire are to be joined to each other, if the force for winding the aluminum wire is weak, the gap between the electric wires becomes large. If the gap between the electric wires is large, the friction force decreases. Also, the brazing material does not penetrate easily, which sometimes results in insufficient joining. Then, when an electric wire is pulled in a manufacturing process of an electric motor,

the electric wire may slip off or a contact failure may occur between electric wires. [0005] An object of the present invention is to prevent slipping off of an electric wire of an electric motor and a contact failure between electric wires of the electric motor. Solution to Problem [0006] An electric motor according to one aspect of the present invention includes:
a first electric wire bundle including two or more first electric wires and having an end twisted to form a plurality of trough portions in a longitudinal direction of the first electric wire bundle;
a second electric wire having an end helically wound around a twisted portion of the first electric wire bundle to fit a part of the second electric wire in at least one of the plurality of trough portions; and
a joining member to join the twisted portion of the first electric wire bundle and a helically wound portion of the second electric wire to each other. Advantageous Effects of Invention
[0007] In the present invention, when a twisted portion of a first electric wire bundle and a helically wound portion of a second electric wire are to be joined to each other, a part of the helically wound portion of the second electric wire is fitted in at least one trough portion formed in the twisted portion of the first electric wire bundle. Accordingly, a joined wire will not slip off easily. Also, a contact failure between joined electric wires will not occur easily.
Brief Description of Drawings
[0008] Fig. 1 is a circuit diagram of a refrigerating cycle apparatus according to a
first embodiment.
Fig. 2 is a circuit diagram of the refrigerating cycle apparatus according to the

first embodiment.
Fig. 3 is a vertical cross-sectional view of a compressor according to the first embodiment.
Fig. 4 is a sectional view taken along a line A-A of a compressor mechanism according to the first embodiment.
Fig. 5 is a plan view of a stator of an electric motor according to the first embodiment.
Fig. 6 is a winding wiring diagram of the stator of the electric motor according to the first embodiment.
Fig. 7 is a winding connection diagram of the stator of the electric motor according to the first embodiment.
Fig. 8 is a side view illustrating an electric wire joint section and insulating paper of the electric motor according to the first embodiment.
Fig. 9 is a side view illustrating a first electric wire bundle of the electric motor according to the first embodiment.
Fig. 10 is a side view illustrating the first electric wire bundle and a second electric wire wound around the first electric wire bundle, of the electric motor according to the first embodiment.
Fig. 11 is a side view illustrating the electric wire joint section of the electric motor according to the first embodiment.
Fig. 12 is a flowchart illustrating a procedure of joining and insulating of electric wires of the electric motor according to the first embodiment.
Description of Embodiments
[0009] Hereinafter, an embodiment of the present invention will be described, using

the drawings. The same or equivalent portions are denoted by the same reference numerals throughout the drawings, and their explanations will be suitably omitted or simplified in the description of the embodiment. In the description of the embodiment, positions, directions, and so on are expressed as "upper", "lower", "left", "right", "front", "behind", "top", "bottom", and so on. It must be noted that these expressions are employed only for the sake of explanatory conveniences and will not limit the actual positions, directions, and so on of an apparatus, instruments, components, and so on. Concerning the configurations of the apparatus, instruments, components, and so on, their materials, shapes, sizes, and so on can be appropriately changed within the scope of the present invention. [0010] First Embodiment
Configurations of an apparatus and a device according to this embodiment, operation of the device according to this embodiment, detailed configurations of components of the device according to this embodiments, and effects of this embodiment will be sequentially described. [0011] * * * Description of Configurations * * *
A configuration of a refrigerating cycle apparatus 10 that is the apparatus according to this embodiment will be described with reference to Figs. 1 and 2. [0012] Fig. 1 illustrates a refrigerant circuit 11 during a cooling operation. Fig. 2 illustrates the refrigerant circuit 11 during a heating operation.
[0013] In this embodiment, the refrigerating cycle apparatus 10 is an air conditioner. The refrigerating cycle apparatus 10 may be, however, an apparatus other than the air conditioner such as a refrigerator or a heat pump cycle apparatus. [0014] The refrigerating cycle apparatus 10 includes the refrigerant circuit 11 in which a refrigerant circulates. The refrigerating cycle apparatus 10 further includes a

compressor 12, a four-way valve 13, a first heat exchanger 14 that is an outdoor heat exchanger, an expansion mechanism 15 that is an expansion valve, and a second heat exchanger 16 that is an indoor heat exchanger. The compressor 12, the four-way valve 13, the first heat exchanger 14, the expansion mechanism 15, and the second heat exchanger 16 are connected to the refrigerant circuit 11.
[0015] The compressor 12 compresses the refrigerant. The four-way valve 13 switches the direction in which the refrigerant flows between during the cooling operation and during the heating operation. The first heat exchanger 14 operates as a condenser during the cooling operation, and radiates heat of the refrigerant compressed by the compressor 12. That is, the first heat exchanger 14 exchanges heat using the refrigerant compressed by the compressor 12. The first heat exchanger 14 operates as an evaporator during the heating operation, and exchanges heat between outdoor air and the refrigerant expanded by the expansion mechanism 15, thereby heating the refrigerant. The expansion mechanism 15 expands the refrigerant the heat of which has been radiated by the condenser. The second heat exchanger 16 operates as a condenser during the heating operation, and radiates heat of the refrigerant compressed by the compressor 12. That is, the second heat exchanger 16 exchanges heat using the refrigerant compressed by the compressor 12. The second heat exchanger 16 operates as an evaporator during the cooling operation, and exchanges heat between indoor air and the refrigerant expanded by the expansion mechanism 15, thereby heating the refrigerant.
[0016] The refrigerating cycle apparatus 10 further includes a controlling device 17. [0017] Specifically, the controlling device 17 is a microcomputer. In Figs. 1 and 2, only connection between the controlling device 17 and the compressor 12 is illustrated; however, the controlling device 17 may be connected not only to the compressor 12 but

also to a component, other than the compressor 12, connected to the refrigerant circuit
11. The controlling device 17 monitors and controls a state of the component
connected to it.
[0018] As the refrigerant circulating in the refrigerant circuit 11, a hydrofluorocarbon
(HFC) refrigerant such as R32, R125, R134a, R407C, and R410A is used.
Alternatively, a hydrofluoroolefin (HFO) refrigerant such as R1123, Rl 132(E),
R1132(Z), R1132a, R1141, R1234yf, R1234ze(E), and R1234ze(Z) is used.
Alternatively, a natural refrigerant such as R290 (propane), R600a (isobutane), R744
(carbon dioxide), and R717 (ammonia) is used. Alternatively, another refrigerant is
used. Alternatively, a mixture of two or more different refrigerants among the above
refrigerants is used.
[0019] A configuration of the compressor 12 that is the device according to this
embodiment will be described with reference to Fig. 3.
[0020] Fig. 3 illustrates a vertical cross section of the compressor 12. Note that in
Fig. 3, hatching indicating a cross section is omitted.
[0021] In this embodiment, the compressor 12 is a hermetic compressor. The
compressor 12 is specifically a one-cylinder rotary compressor, but may be a rotary
compressor with two or more cylinders, a scroll compressor, or a reciprocating
compressor.
[0022] The compressor 12 includes a container 20, a compression mechanism 30, an
electric motor 40, and a crankshaft 50.
[0023] The container 20 is specifically a hermetic container. In the bottom section
of the container 20, refrigerating machine oil 25 is reserved. A suction pipe 21 for
suctioning the refrigerant and a discharge pipe 22 for discharging the refrigerant are
attached to the container 20.

[0024] The electric motor 40 is housed in the container 20. Specifically, the electric
motor 40 is disposed at an upper section inside the container 20.
[0025] The compression mechanism 30 is housed in the container 20. Specifically,
the compression mechanism 30 is disposed at a lower section inside the container 20.
That is, the compression mechanism 30 is positioned below the electric motor 40 inside
the container 20.
[0026] The electric motor 40 and the compression mechanism 30 are connected to
each other by the crankshaft 50. The crankshaft 50 forms an oil supply path for the
refrigerating machine oil 25 and a rotating shaft of the electric motor 40.
[0027] Along with rotation of the crankshaft 50, the refrigerating machine oil 25 is
pumped up by an oil pump provided at the lower section of the crankshaft 50, and is
supplied to each sliding section of the compression mechanism 30 to lubricate each
sliding section of the compression mechanism 30. As the refrigerating machine oil 25,
polyol ester (POE), polyvinyl ether (PVE), alkyl benzene (AB), or the like, each of
which is synthetic oil, is used.
[0028] The compression mechanism 30 is driven by the rotating force of the electric
motor 40 which is transmitted via the crankshaft 50, so as to compress the refrigerant.
This refrigerant is specifically a low-pressure gas refrigerant suctioned by the suction
pipe 21. The high-temperature, high-pressure gas refrigerant compressed by the
compression mechanism 30 is discharged from the compression mechanism 30 into the
container 20.
[0029] The crankshaft 50 includes an eccentric shaft section 51, a main shaft section
52, and an auxiliary shaft section 53 which are provided in the order of the main shaft
section 52, the eccentric shaft section 51, and the auxiliary shaft section 53 in the axial
direction. That is, the main shaft section 52 is provided at one-end side in the axial

direction of the eccentric shaft section 51. The auxiliary shaft section 53 is provided at
the other-end side in the axial direction of the eccentric shaft section 51. The eccentric
shaft section 51, the main shat section 52, and the auxiliary shaft section 53 have each a
column shape. The main shaft section 52 and the auxiliary shaft section 53 are
provided such that their central axes coincide, that is, they are provided coaxially The
eccentric shaft section 51 is provided such that its central axis deviates from the central
axes of the main shaft section 52 and auxiliary shaft section 53. When the main shaft
section 52 and the auxiliary shaft section 53 rotate about their central axes, the eccentric
shaft section 51 rotates eccentrically.
[0030] Hereinafter, details of the electric motor 40 will be described.
[0031] In this embodiment, the electric motor 40 is an induction electric motor. The
electric motor 40 may be, however, a motor other than an induction electric motor, such
as a brushless direct current (DC) motor.
[0032] The electric motor 40 includes a stator 41 and a rotor 42.
[0033] The stator 41 has a cylinder shape and is fixed to be in contact with an inner
circumferential surface of the container 20. The rotor 42 has a column shape and is
disposed inside the stator 41 with a gap with a width of 0.3 mm or more to 1.0 mm or
less.
[0034] The stator 41 includes a stator iron core 43 and windings 44. The stator iron
core 43 is manufactured by punching a plurality of magnetic steel sheets, each of which
contains iron as a major component and has a thickness of 0.1 mm or more to 1.5 mm or
less, into a predetermined shape, laminating the punched sheets in the axial direction,
and fixing the sheets by caulking, welding, or the like. The stator iron core 43 has an
outer diameter larger than the inner diameter of an intermediate portion of the container
20 and is fixed inside the container 20 by shrinkage fitting. The windings 44 are

wound around the stator iron core 43. Specifically, the windings 44 are wound around the stator iron core 43 via an insulating member. Each winding 44 is constituted from a core wire and an at-least-one-layer film covering the core wire. In this embodiment, the material of the core wire is either copper or aluminum as will be described later. The material of the film is amide-imide (AI)/ester-imide (EI). The material of the insulating member is polyethylene terephthalate (PET). The material of the insulating member may be polybutylene terephthalate (PBT), tetrafluoroethylene-hexafluoropropylene copolymer (FEP),
tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), polytetrafluoroethylene (PTFE), liquid-crystal polymer (LCP), polyphenylene sulfide (PPS), or phenol resin. The windings 44 are connected to first ends of lead wires 45. [0035] A plurality of cutouts are formed at equal intervals in the circumferential direction on the outer circumference of the stator iron core 43. Each cutout serves as a path for the gas refrigerant emitted from a discharge muffler 35 (to be described later) to the space in the container 20. Each cutout also serves as a path for the refrigerating machine oil 25 returning from above the electric motor 40 to the bottom section of the container 20.
[0036] The rotor 42 is a squirrel-cage rotor made by aluminum die casting. The rotor 42 includes a rotor iron core 46, conductors (not illustrated), and end rings 47. Similarly to the stator iron core 43, the rotor iron core 46 is manufactured by punching a plurality of magnetic steel sheets, each of which contains iron as a major component and has a thickness of 0.1 mm or more to 1.5 mm or less, into a predetermined shape, laminating the punched sheets in the axial direction, and fixing the sheets by caulking, welding, or the like. The conductors are made of aluminum, copper, or the like. The conductors are charged or inserted in a plurality of slots formed in the rotor iron core 46.

The end rings 47 short-circuit the two ends of each conductor. A squirrel-cage winding is thus formed.
[0037] A shaft hole, into which the main shaft section 52 of the crankshaft 50 is fitted by shrinkage fit, or pressed, is formed in the center of the rotor iron core 46 in plan view. Though not illustrated, a plurality of through holes penetrating in the axial direction are formed around the shaft hole of the rotor iron core 46. Each through hole serves as a path for a gas refrigerant emitted from the discharge muffler 35 (to be described later) to the space in the container 20, as each cutout in the stator iron core 43 does. [0038] Though not illustrated, if the electric motor 40 is formed as the brushless DC motor, permanent magnets are inserted in a plurality of insertion holes formed in the rotor iron core 46. The permanent magnets constitute magnetic poles. As each permanent magnet, a ferrite magnet or a rare-earth magnet is used. In order to prevent the permanent magnets from slipping off in the axial direction, an upper end plate and a lower end plate are provided at the two ends in the axial direction of the rotor 42, respectively. The upper end plate and the lower end plate also serve as a rotation balancer. The upper end plate and the lower end plate are fixed to the rotor iron core 46 by means of fixing members such as fixing rivets.
[0039] A terminal 24 connected to an external power supply such as an inverter apparatus is attached to the top section of the container 20. Specifically, the terminal 24 is a glass terminal. In this embodiment, the terminal 24 is fixed to the container 20 by welding. Second ends of the lead wires 45 are connected to the terminal 24. Thereby, the terminal 24 and the windings 44 of the electric motor 40 are electrically connected.
[0040] The discharge pipe 22 whose both axial ends are open is also attached to the top section of the container 20. The gas refrigerant discharged from the compression

mechanism 30 passes from the space in the container 20 through the discharge pipe 22,
and is discharged to the refrigerant circuit 11 of an outside.
[0041] Hereinafter, details of the compression mechanism 30 will be described with
reference to Fig. 4 as well as Fig. 3.
[0042] Fig. 4 illustrates a cut plane obtained when the compression mechanism 30 is
cut along an A-A line illustrated in Fig. 1, namely by a plane perpendicular to the axial
direction of the crankshaft 50. Note that in Fig. 4, hatching indicating a cross section
is omitted.
[0043] The compression mechanism 30 includes a cylinder 31, a rolling piston 32, a
main bearing 33, an auxiliary bearing 34, and a discharge muffler 35.
[0044] An inner circumference of the cylinder 31 has a circular shape in plan view.
Inside the cylinder 31, a cylinder chamber 91 that is a space circular in plan view is
formed. A suction hole for suctioning the gas refrigerant from the refrigerant circuit 11
is formed in the outer circumferential surface of the cylinder 31. The refrigerant
suctioned via the suction port is compressed in the cylinder chamber 91. Both axial
ends of the cylinder 31 are open.
[0045] The rolling piston 32 has a ring shape. Accordingly, each of an inner
circumference and an outer circumference of the rolling piston 32 is circular in plan
view. The rolling piston 32 rotates eccentrically in the cylinder chamber 91. The
rolling piston 32 is slidably fitted to the eccentric shaft section 51 of the crankshaft 50
that serves as the rotation axis of the rolling piston 32.
[0046] A vane groove 92 connecting to the cylinder chamber 91 and extending in the
radial direction is formed in the cylinder 31. A back pressure chamber 93 that is a
space circular in plan view and connects to the vane groove 92 is formed at the outer
side of the vane groove 92. A vane 94 is disposed in the vane groove 92 to partition

the cylinder chamber 91 into a suction chamber that is a low-pressure operation chamber and a compression chamber that is a high-pressure operation chamber. The vane 94 is shaped like a plate whose tip is rounded. The vane 94 reciprocates while sliding in the vane groove 92. The vane 94 is constantly pressed against the rolling piston 32 by a vane spring provided in the back pressure chamber 93. Since the pressure inside the container 20 is high, a force generated due to a difference between the pressure inside the container 20 and the pressure inside the cylinder chamber 91 acts on the vane back surface being the surface of the vane 94 on the side of the back pressure chamber 93 when the operation of the compressor 12 starts. Therefore, the vane spring is used for the purpose of pressing the vane 94 against the rolling piston 32 mainly at startup of the compressor 12 when there is no difference between the pressure inside the container 20 and the pressure inside the cylinder chamber 91. [0047] The main bearing 33 has an inverse T shape in side view. The main bearing
33 is slidably fitted to the main shaft section 52, which is a portion upper than the
eccentric shaft section 51, of the crankshaft 50. A through hole 54 serving as an oil
supply path is formed in the crankshaft 50 in the axial direction. As the refrigerating
machine oil 25 suctioned via the through hole 54 is supplied to the space between the
main bearing 33 and the main shaft section 52, an oil film is formed in this space. The
main bearing 33 closes the upper sides of the cylinder chamber 91 and vane groove 77
of the cylinder 31. That is, the main bearing 33 closes the upper sides of the two
operation chambers in the cylinder 31.
[0048] The auxiliary bearing 34 has a T shape in side view. The auxiliary bearing
34 is slidably fitted to the auxiliary shaft section 53, which is a portion lower than the
eccentric shaft section 51, of the crankshaft 50. As the refrigerating machine oil 25
suctioned via the through hole 54 of the crankshaft 50 is supplied to the space between

the auxiliary bearing 34 and the auxiliary shaft section 53, an oil film is formed in this space. The auxiliary bearing 34 closes the lower sides of the cylinder chamber 91 and vane groove 92 of the cylinder 31. That is, the auxiliary bearing 34 closes the lower sides of the two operation chambers in the cylinder 31.
[0049] The main bearing 33 and the auxiliary bearing 34 are fixed to the cylinder 31 by fasteners 36 such as bolts and support the crankshaft 50 that serves as the rotation axis of the rolling piston 32. The main bearing 33 supports the main shaft section 52 via liquid lubrication of the oil film between the main bearing 33 and the main shaft section 52, without coming into contact with the main shaft section 52. As the main bearing 33 does, the auxiliary bearing 34 supports the auxiliary shaft section 53 via liquid lubrication of the oil film between the auxiliary bearing 34 and the auxiliary shaft section 53, without coming into contact with the auxiliary shaft section 53. [0050] Though not illustrated, the main bearing 33 has a discharge port for discharging the refrigerant compressed in the cylinder chamber 91 to the refrigerant circuit 11. The discharge port is located at such a position that it connects to the compression chamber when the cylinder chamber 91 is partitioned into the suction chamber and the compression chamber by the vane 94. A discharge valve that blocks the discharge port openably/closably is attached to the main bearing 33. The discharge port is closed until the gas refrigerant in the compression chamber reaches a desired pressure, and is opened when the gas refrigerant in the compression chamber reaches a desired pressure. The discharge timing of the gas refrigerant from the cylinder 31 is controlled by this operation.
[0051] The discharge muffler 35 is attached to the outer side of the main bearing 33. The high-temperature, high-pressure gas refrigerant which is discharged when the discharge valve is opened first enters the discharge muffler 35 and is then emitted to the

space in the container 20 from the discharge muffler 35. The discharge port and the discharge vale may be provided to the auxiliary bearing 34, or both of the main bearing 33 and the auxiliary bearing 34. The discharge muffler 35 is attached to the outer side of the bearing to which the discharge port and the discharge valve are provided. [0052] A suction muffler 23 is provided beside the container 20. The suction muffler 23 suctions a low-pressure gas refrigerant from the refrigerant circuit 11. When a liquid refrigerant returns, the suction muffler 23 prevents the liquid refrigerant from directly entering the cylinder chamber 91 of the cylinder 31. The suction muffler 23 is connected to the suction port formed in the outer circumferential surface of the cylinder 31 via the suction pipe 21. The suction port is located at such a position that it connects to the suction chamber when the cylinder chamber 91 is partitioned into the suction chamber and the compression chamber by the vanes 94. The body of the suction muffler 23 is fixed to a side surface of the container 20 by welding or the like. [0053] In this embodiment, the materials of the cylinder 31, the main bearing 33, and the auxiliary bearing 34 are sintered steel, but may be gray cast iron or carbon steel. The material of the rolling piston 32 is alloy steel containing chromium and so on. The material of the vane 94 is high speed tool steel.
[0054] Though not illustrated, in a case where the compressor 12 is constituted as a swing type rotary compressor, the vane 94 is formed integrally with the rolling piston 32. When the crankshaft 50 is driven, the vane 94 reciprocally moves along a groove in the support body rotatably attached to the rolling piston 32. The vane 94 moves forward and backward in the radial direction while swinging, as the rolling piston 32 rotates, so as to partition the interior of the cylinder chamber 91 into the compression chamber and the suction chamber. The support body is formed of two column shape members each having a semicircular cross section. The support body is rotatably fitted in a circular

holding hole formed at an intermediate portion between the suction port and the
discharge port of the cylinder 31.
[0055] *** Description of Operation ***
The operation of the compressor 12 that is the device according to this embodiment will be described with reference to Fig. 3 and Fig. 4. The operation of the compressor 12 corresponds to a refrigerant compression method according to this embodiment.
[0056] Power is supplied from the terminal 24 to the stator 41 of the electric motor 40 via the lead wires 45. This causes current to flow through the windings 44 of the stator 41, and magnetic flux is generated from the windings 44. The rotor 42 of the electric motor 40 rotates by the action of the magnetic flux generated from the windings 44 and magnetic flux generated from the squirrel-cage winding of the rotor 42. The rotation of the rotor 42 causes the crankshaft 50 fixed to the rotor 42 to rotate. In association with the rotation of the crankshaft 50, the rolling piston 32 of the compression mechanism 30 eccentrically rotates in the cylinder chamber 91 of the cylinder 31 of the compression mechanism 30. The cylinder chamber 91 which is the space between the cylinder 31 and the rolling piston 32 is divided into a suction chamber and a compression chamber by the vane 94. In association with the rotation of the crankshaft 50, the volume of the suction chamber and the volume of the compression chamber change. In the suction chamber, a gradual increase in the volume causes a low-pressure gas refrigerant to be suctioned from the suction muffler 23. In the compression chamber, a gradual decrease in the volume causes the gas refrigerant inside to be compressed. The compressed gas refrigerant, the pressure and temperature of which have become high, is discharged from the discharge muffler 35 to the space in the container 20. The discharged gas refrigerant further passes through

the electric motor 40 and is discharged outside the container 20 through the discharge pipe 22 at the top section of the container 20. The refrigerant discharged outside the container 20 passes through the refrigerant circuit 11 and returns to the suction muffler 23 again. [0057] *** Description of Detailed Configuration ***
Detailed configuration of the stator 41 of the electric motor 40, which is a component of the device according to this embodiment will be described with reference to Figs. 5 to 8.
[0058] Fig. 5 is a plan view of the stator 41.
[0059] As described above, the stator 41 includes the stator iron core 43 and the windings 44. Three lead wires 45 are connected to the windings 44. The lead wires 45 are used for connecting the windings 44 and the terminal 24 attached to the container 20. The windings 44 are each configured by combining an aluminum wire and a copper wire.
[0060] As illustrated in Figs. 6 and 7, in this embodiment, the windings 44 are bifilar-winding stator windings of a three-phase electric motor. Out of the two windings of each bifilar winding, one winding is constituted of a copper wire and the other winding is constituted of an aluminum wire.
[0061] The windings 44 comprise three independent winding groups. Specifically, the windings 44 comprise a U-phase winding section 61, a V-phase winding section 62, and a W-phase winding section 63. Each winding group is a bifilar winding of one copper wire and one aluminum wire. Specifically, the U-phase winding section 61 comprises a U-phase first winding section 64 formed of a copper wire and a U-phase second winding section 65 formed of an aluminum wire. The V-phase winding section 62 comprises a V-phase first winding section 66 formed of a copper wire and a V-phase

second winding section 67 formed of an aluminum wire. The W-phase winding section 63 comprises a W-phase first winding section 68 formed of a copper wire and a W-phase second winding section 69 formed of an aluminum wire. [0062] Each of the U-phase first winding section 64 and the U-phase second winding section 65 is constituted of four coils. Specifically, the U-phase first winding section 64 is constituted of U-phase first coils 64a, 64b, 64c, and 64d. The U-phase second winding section 65 is constituted of U-phase second coils 65a, 65b, 65c, and 65d. Each of the V-phase first winding section 66 and the V-phase second winding section 67 is also constituted of four coils. Specifically, the V-phase first winding section 66 is constituted of V-phase first coils 66a, 66b, 66c, and 66d. The V-phase second winding section 67 is constituted of V-phase second coils 67a, 67b, 67c, and 67d. Each of the W-phase first winding section 68 and the W-phase second winding section 69 is also constituted of four coils. Specifically, the W-phase first winding section 68 is constituted of W-phase first coils 68a, 68b, 68c, and 68d. The W-phase second winding section 69 is constituted of W-phase second coils 69a, 69b, 69c, and 69d. [0063] In this embodiment, the three copper wires and the three aluminum wires are gathered at one portion and connected to each other to form a neutral point 70. That is, a U-phase first terminal wire 64e which is one terminal of the U-phase first coil 64d and a U-phase second terminal wire 65 e which is one terminal of the U-phase second coil 65d are connected to the neutral point 70. A V-phase first terminal wire 66e which is one terminal of the V-phase first coil 66d and a V-phase second terminal wire 67e which is one terminal of the V-phase second coil 67d are also connected to the neutral point 70. A W-phase first terminal wire 68e which is one terminal of the W-phase first coil 68d and a W-phase second terminal wire 69e which is one terminal of the W-phase second coil 69d are also connected to the neutral point 70.

[0064] As illustrated in Fig. 8, the U-phase first terminal wire 64e, the V-phase first terminal wire 66e, and the W-phase first terminal wire 68e are twisted together in the length direction to form a twisted connecting section 72. The U-phase second terminal wire 65e, the V-phase second terminal wire 67e, and the W-phase second terminal wire 69e are wound together around trough portions 73 of the twisted connecting section 72 at interval D in the length direction, to form a wound connecting section 74. The twisted connecting section 72 and the wound connecting section 74 are joined to each other with a joining member 75 to form an electric wire joint section 76 corresponding to the neutral point 70. An insulating member 71 is mounted on the electric wire joint section 76. The electric wire joint section 76 on which the insulating member 71 is mounted is buried in the gaps of the windings 44 and is fixed. [0065] The insulating member 71 may be a tube, but is insulating paper in this embodiment. As a result, a work of shrinking the tube to bring the tube into tight contact with the electric wire joint section 76 is unnecessary, improving the work efficiency. In this embodiment, the material of the insulating paper is PET. An insulating sheet may be employed instead of the insulating paper. [0066] The joining member 75 is specifically a brazing material containing a flux. A residue of the flux accordingly adheres to the surface of the brazing material of the electric wire joint section 76 to make the surface of the electric wire joint section 76 not smooth but rough. In this embodiment, since the brazing material contains the flux, the work of dipping the electric wire joint section 76 in a flux tank before brazing is unnecessary, which enhances the work efficiency.
[0067] As the brazing material, it is necessary to use a brazing filler metal whose melting point is sufficiently lower than the melting point of the base material. Therefore, in this embodiment, it is preferable that a brazing filler metal whose melting

point is lower by 150°C or more than both the melting point of the copper wires and the melting point of the aluminum wires be used as the brazing material. [0068] In addition, as the brazing material, it is necessary to use a brazing filler metal whose melting point is sufficiently higher than the temperature inside the container 20 of the compressor 12. Therefore, in this embodiment, it is preferable to use as the brazing material a brazing filler metal whose melting point is 400°C or higher. During operation of the compressor 12, the temperature of the windings 44 sometimes increases to approximately 200°C momentarily. By using the brazing filler metal whose melting point is 400°C or higher, fusing of the electric wire joint section 76 can be prevented. [0069] As a specific example of a brazing filler metal whose melting point is lower by 150°C or more than both the melting point of the copper wires and the melting point of the aluminum wires and is 400°C or higher, a Zn-Al based brazing filler metal may be used.
[0070] As a specific example of the flux contained in the brazing material, cesium fluoride, or a mixture of aluminum fluoride and cesium fluoride may be used. [0071] In this embodiment, the copper wires are connected after twisting, and the aluminum wires are connected after they are wound around the trough portions of the twisted connecting section 72. This improves the friction force between the electric wires and increases the joining strength of the electric wires. Hence, when an electric wire is pulled, the electric wire will not slip off easily from the electric wire joint section 76. That is, according to this embodiment, a joint failure of the windings 44 of the electric motor 40 can be prevented.
[0072] According to this embodiment, the aluminum wires are brazed after they are wound around the trough portions 73 of the twisted connecting section 72 at the interval D in the length direction. Therefore, the joining member 75 which is a brazing

material can easily penetrate to a position corresponding to the interval D to achieve a good joint state between the copper wires and the aluminum wires. [0073] The insulating member 71 is mounted on the electric wire joint section 76 to wrap the electric wire joint section 76. The inner surface of the insulating member 71 is brought into contact with the surface of the electric wire joint section 76. Since the surface of the electric wire joint section 76 is rough, a friction force acts on the contact surface of the insulating member 71 and the contact surface of the electric wire joint section 76. Therefore, the electric wire joint section 76 will not slip off easily from the insulating member 71. That is, according to this embodiment, an insulation failure of the windings 44 of the electric motor 40 can be prevented. In this embodiment, since the electric wire joint section 76 does not sip off easily from the insulating member 71 by utilizing the residue of the flux adhered to the surface of the electric wire joint section 76, the work of cleaning off the flux is not necessary, thus enhancing the work efficiency.
[0074] The electric wire joint section 76 and the insulating member 71 may also be fixed together with varnish. Then, the electric wire joint section 76 less easily slips off from the insulating member 71.
[0075] Procedures for joining and insulating electric wires according to this embodiment will be described with reference to Figs. 8 to 12. These procedures correspond to an electric wire joining method that is part of a method of manufacturing the electric motor 40.
[0076] In step SI of Fig. 12, as illustrated in Fig. 9, an end of a first electric wire bundle 81 including three first electric wires is twisted to form a plurality of trough portions 73 in the longitudinal direction of the first electric wire bundle 81. Each first electric wire may be an arbitrary electric wire and is a copper wire in this embodiment,

as described above.
[0077] Specifically, in step SI, the insulating films at the ends of the U-phase first terminal wire 64e, V-phase first terminal wire 66e, and W-phase first terminal wire 68e are removed by machine peeling or another method. After that, as illustrated in Fig. 9, the U-phase first terminal wire 64e, V-phase first terminal wire 66e, and W-phase first terminal wire 68e are bundled together and twisted to form the twisted connecting section 72. The number of times of twisting is desirably two or more to five or less and more preferably three. The trough portions 73 corresponding in number to the number of times of twisting and the number of twisted electric wires are formed in the twisted connecting section 72.
[0078] In step S2 of Fig. 12, as illustrated in Fig. 10, while fitting a part of each second electric wire 82 in at least one of the plurality of trough portions 73 formed in the twisted portion of the first electric wire bundle 81 in the longitudinal direction of the first electric wire bundle 81, an end of each second electric wire 82 is helically wound around the twisted portion of the first electric wire bundle 81. In this embodiment, the end of each second electric wire 82 is helically wound at interval D in the length direction of the first electric wire bundle 81. Each second electric wire 82 may be an arbitrary electric wire and is an aluminum wire in this embodiment, as described above. The number of the second electric wires 82 is two or more in this embodiment, and specifically is three.
[0079] Specifically, in step S2, the insulating films at the ends of the U-phase second terminal wire 65e, V-phase second terminal wire 67e, and W-phase second terminal wire 69e are removed by machine peeling or another method. After that, as illustrated in Fig. 10, the U-phase second terminal wire 65e, V-phase second terminal wire 67e, and W-phase second terminal wire 69e are bundled together and wound around the trough

portions 73 of the twisted connecting section 72 to form the wound connecting section 74. The interval D formed in the wound connecting section 74 in the length direction is desirably an interval of 1 mm or more to 4 mm or less, and is more desirably an interval of 2 mm or more to 3 mm or less.
[0080] In this embodiment, two or more portions of each second electric wire 82 are fitted in different trough portions 73 out of the plurality of trough portions 73. Specifically, the U-phase second terminal wire 65e, the V-phase second terminal wire 67e, and the W-phase second terminal wire 69e are wound around the twisted connecting section 72 twice each, such that the first-time wound portion and the second-time wound portion are fitted in different trough portions 73. [0081] In step S3 of Fig. 12, as illustrated in Fig. 11, the twisted portion of the first electric wire bundle 81 and the helically wound portion of each second electric wire 82 are joined to each other with the joining member 75. Specifically, the twisted connecting section 72 and the wound connecting section 74 are joined to each other with a brazing material containing a flux, that is the joining member 75, to form the electric wire joint section 76.
[0082] In step S4 of Fig. 12, as illustrated in Fig. 8, the joined portion of the first electric wire bundle 81 and the joined portion of each second electric wire 82 that are joined together with the joining member 75 are wrapped with the insulating member 71. Specifically, insulating paper, which is the insulating member 71, having at least one open end is mounted on the electric wire joint section 76. [0083] *** Description of Effect of Embodiment ***
In this embodiment, when the twisted portion of the first electric wire bundle 81 and the helically wound portion of each second electric wire 82 are joined to each other, a part of the helically wound portion of each second electric wire 82 is fitted in at

least one trough portion 73 formed in the twisted portion of the first electric wire bundle 81. Thus, each joined electric wire does not slip off easily. Also, a contact failure of the joined electric wires does not occur easily.
[0084] In this embodiment, the insulating member 71 wraps the joined portion of the first electric wire bundle 81 and the joined portion of each second electric wire 82, in a state where a residue of the flux adheres to the surface of the brazing material that is the joining member 75, and the inner surface of the insulating member 71 is in contact with the surface of the brazing material. As a result, the joint portion of the first electric wire bundle 81 and the joined portion of each second electric wire 82 do not slip off from the insulating member 71 easily.
[0085] Aluminum is softer than copper. In this embodiment, when the copper wires and the aluminum wires are to be joined to each other, the aluminum wires are helically wound around the copper wires. Hence, the winding workability improves. As the aluminum wires can have a large surface area in the electric wire joint section 76, the activated flux removes an oxide film on the surfaces of the aluminum wires, and the brazing filler metal with an improved flowability penetrates into the entire joint section of the electric wires easily.
[0086] According to this embodiment, since the friction force between the electric wires increases, the tensile strength of the electric wires increases, so that the compressor 12 that is highly reliable and free from manufacturing defect can be obtained.
[0087] According to this embodiment, since a flux residue component having a large friction adheres to the surface of the electric wire joint section 76, the insulating member 71 becomes less slippery to avoid a situation where the electric wire joint section 76 is exposed undesirably. As a result, the compressor 12 that is highly

reliable and free from an insulation failure can be obtained. [0088] *** Other Configuration ***
In this embodiment, the number of first electric wires included in the first electric wire bundle 81 is three. As far as the first electric wire bundle 81 includes two or more first electric wires, the effect as described above can be obtained. In this embodiment, the number of the second electric wires 82 is three. As far as there are one or more second electric wires 82, the effect as described above can be obtained. [0089] An embodiment of the present invention has been described above; however, this embodiment may be implemented partly. Note that the present invention is not limited to this embodiment, and various modifications may be made as necessary.
Reference Signs List
[0090] 10: refrigerating cycle apparatus; 11: refrigerant circuit; 12: compressor; 13: four-way valve; 14: first heat exchanger; 15: expansion mechanism; 16: second heat exchanger; 17: controlling device; 20: container; 21: suction pipe; 22: discharge pipe; 23: suction muffler; 24: terminal; 25: refrigerating machine oil; 30: compression mechanism; 31: cylinder; 32: rolling piston; 33: main bearing; 34: auxiliary bearing; 35: discharge muffler; 36: fastener; 40: electric motor; 41: stator; 42: rotor; 43: stator iron core; 44: winding; 45: lead wire; 46: rotor iron core; 47: end ring; 50: crankshaft; 51: eccentric shaft section; 52: main shaft section; 53: auxiliary shaft section; 54: through hole; 61: U-phase winding section; 62: V-phase winding section; 63: W-phase winding section; 64a, 64b, 64c, 64d: U-phase first coil; 64e: U-phase first terminal wire; 65: U-phase second winding section; 65a, 65b, 65c, 65d: U-phase second coil; 65e: U-phase second terminal wire; 66: V-phase first winding section; 66a, 66b, 66c, 66d: V-phase first coil; 66e: V-phase first terminal wire; 67: V-phase second winding section; 67a,

67b, 67c, 67d: V-phase second coil; 68: W-phase first winding section; 67e: V-phase second terminal wire; 68a, 68b, 68c, 68d: W-phase first coil; 68e; W-phase first terminal wire; 69: W-phase second winding section; 69a, 69b, 69c, 69d: W-phase second coil; 69e: W-phase second terminal wire; 70: neutral point; 71: insulating member; 72: twisted connecting section; 73: trough portion; 74: wound connecting section; 75: joining member; 76: electric wire joint section; 81: first electric wire bundle; 82: second electric wire; 91: cylinder chamber; 92: vane groove; 93: back pressure chamber; 94: vane

Claims
[Claim 1] An electric motor comprising:
a first electric wire bundle including two or more first electric wires and having an end twisted to form a plurality of trough portions in a longitudinal direction of the first electric wire bundle;
a second electric wire having an end helically wound around a twisted portion of the first electric wire bundle to fit a part of the second electric wire in at least one of the plurality of trough portions; and
a joining member to join the twisted portion of the first electric wire bundle and a helically wound portion of the second electric wire to each other. [Claim 2] The electric motor according to claim 1,
wherein the first electric wire bundle includes, as the two or more first electric wires, two or more copper wires, and
wherein the second electric wire is one or more aluminum wires. [Claim 3] The electric motor according to claim 1 or 2, wherein two or more portions of the second electric wire are fitted in different trough portions out of the plurality of trough portions.
[Claim 4] The electric motor according to any one of claims 1 to 3, further comprising an insulating member to wrap a joined portion of the first electric wire bundle and a joined portion of the second electric wire that are joined to each other with the joining member,
wherein the joining member is a brazing material containing a flux, and
wherein the insulating member wraps the joined portion of the first electric wire bundle and the joined portion of the second electric wire, in a state where a residue

of the flux adheres to a surface of the brazing material, and an inner surface of the
insulating member is in contact with the surface of the brazing material.
[Claim 5] The electric motor according to any one of claims 1 to 4, wherein the end of
the second electric wire is helically wound at interval in a length direction of the first
electric wire bundle.
[Claim 6] A compressor comprising the electric motor according to any one of claims 1
to 5, and a compression mechanism driven by the electric motor.
[Claim 7] A refrigerating cycle apparatus comprising the compressor according to claim
6.
[Claim 8] A method of manufacturing an electric motor, the manufacturing method
comprising:
twisting an end of a first electric wire bundle including two or more first electric wires;
winding an end of a second electric wire around a twisted portion of the first electric wire bundle while fitting a part of the second electric wire in at least one of a plurality of trough portions formed in the twisted portion of the first electric wire bundle in a longitudinal direction of the first electric wire bundle; and
joining the twisted portion of the first electric wire bundle and a helically wound portion of the second electric wire to each other with a joining member.