WO2024089866A1

WO2024089866A1 - Stator, electric motor, compressor and refrigeration cycle apparatus

Info

Publication number: WO2024089866A1
Application number: PCT/JP2022/040310
Authority: WO
Inventors: 浩二矢部; 勇二廣澤
Original assignee: 三菱電機株式会社
Priority date: 2022-10-28
Filing date: 2022-10-28
Publication date: 2024-05-02

Abstract

This stator constitutes an electric motor together with a rotor having 10 × N magnetic poles (N is a natural number). The stator includes an annular stator core in which 12 × N teeth are arranged in the circumferential direction, an inner winding wound around each of the 12 × N teeth, and an outer winding wound around the outside of the inner winding. The inner winding and the outer winding are connected in parallel. The inner winding wound around the first tooth of the 12 × N teeth and the inner winding wound around the second tooth are connected in series. The outer winding wound around the first tooth and the outer winding wound around the second tooth are connected in series.

Description

Stator, motor, compressor and refrigeration cycle device

This disclosure relates to a stator, an electric motor, a compressor, and a refrigeration cycle device.

The stator of an electric motor has a stator core and windings. The stator core has multiple teeth, and slots are formed between adjacent teeth. The windings are wound around the teeth and housed in the slots.

For example, Patent Document 1 discloses providing a first three-phase winding on the inner layer side and a second three-phase winding on the outer layer side, each of which is delta-connected. The winding portions of the U-phase, V-phase, and W-phase of the first three-phase winding skip over two teeth and are wound with concentrated winding on the teeth on both sides. The second three-phase winding is wound in a similar manner.

JP 2008-193785 A (see Figs. 5 and 7)

However, with conventional technology, many jumper wires are required to connect the winding sections, and the jumper wires are also long. This requires complex wiring to avoid interference between the winding sections and the jumper wires, resulting in a problem of low workability.

This disclosure has been made to solve the above problems, and aims to simplify the wiring of the windings and improve workability.

The stator of the present disclosure is a stator that constitutes an electric motor together with a rotor having 10×N magnetic poles (N is a natural number). The stator has an annular stator core with 12×N teeth arranged in the circumferential direction, an inner winding wound on each of the 12×N teeth, and an outer winding wound outside the inner winding. The inner winding and the outer winding are connected in parallel. The inner winding wound on the first tooth of the 12×N teeth and the inner winding wound on the second tooth are connected in series. Furthermore, the outer winding wound on the first tooth and the outer winding wound on the second tooth are connected in series.

In the present disclosure, the inner windings wound around two teeth are connected in series, and the outer windings wound around two teeth are also connected in series, and the inner windings and outer windings are connected in parallel, making wiring easy and improving workability.

1 is a cross-sectional view showing an electric motor according to a first embodiment of the present invention; 3 is a cross-sectional view showing the arrangement of windings in the stator of the first embodiment. FIG. 2 is a diagram showing a winding portion wound around two teeth of a stator according to the first embodiment; FIG. 4 is a diagram showing a connection state between an inner winding and an outer winding in the first embodiment. FIG. FIG. 2 is a diagram showing a connection state of the winding parts of each phase according to the first embodiment; FIG. 2 is a diagram showing conductors constituting an inner winding and an outer winding in the first embodiment. 11A and 11B are diagrams illustrating another configuration example of the core segment of the first embodiment. FIG. 2 is a perspective view showing a stator according to the first embodiment. 2 is a perspective view showing a core segment and an insulator according to the first embodiment. FIG. FIG. 2 is a perspective view showing a portion of the stator according to the first embodiment. 11 is a perspective view showing another part of the stator according to the first embodiment, different from that shown in FIG. 10 . 1 is a vertical cross-sectional view showing a compressor to which the electric motor of embodiment 1 can be applied; FIG. 13 is a diagram showing a refrigeration cycle device including the compressor shown in FIG. 12 .

Embodiment 1.
<Motor configuration>
1 is a cross-sectional view showing an electric motor 100 according to a first embodiment. The electric motor 100 includes a rotor 5 and an annular stator 1 provided to surround the rotor 5. An air gap is provided between the stator 1 and the rotor 5.

Hereinafter, the central axis of rotation of the rotor 5 will be referred to as the axis Ax. The direction of the axis Ax will be referred to as the "axial direction." The circumferential direction centered on the axis Ax will be referred to as the "circumferential direction," and the radial direction centered on the axis Ax will be referred to as the "radial direction."

<Configuration of Rotor 5>
The rotor 5 has a rotor core 50, a permanent magnet 55, and a shaft 60. The rotor core 50 is made of a plurality of steel plates laminated in the axial direction. The steel plates are, for example, electromagnetic steel plates. The thickness of the steel plates is, for example, 0.1 mm to 1.0 mm.

A number of magnet insertion holes 51 are formed along the outer periphery of the rotor core 50. The number of magnet insertion holes 51 is 10 x N (N is a natural number). The magnet insertion holes 51 are formed at equal intervals in the circumferential direction. One flat permanent magnet 55 is inserted into each magnet insertion hole 51.

The permanent magnets 55 are made of rare earth magnets. The rare earth magnets are, for example, neodymium magnets containing neodymium (Nd), iron (Fe) and boron (B). The permanent magnets 55 have a thickness in the radial direction of the rotor core 50, and are magnetized in that thickness direction.

The permanent magnet 55 placed in each magnet insertion hole 51 constitutes one magnetic pole. Since the number of magnet insertion holes 51 is 10 x N, the number of poles of the rotor 5 is 10 x N.

In the example shown in FIG. 1, N=1. That is, the number of magnet insertion holes 51 (i.e., the number of permanent magnets 55) is 10, and the number of poles of the rotor 5 is 10. However, N may be 2 or more.

Here, one permanent magnet 55 is placed in each magnet insertion hole 51, but two or more permanent magnets 55 may be placed in each magnet insertion hole 51. Also, here, the magnet insertion hole 51 extends linearly in a plane perpendicular to the axis Ax, but it may also extend, for example, in a V-shape.

The rotor core 50 has a central hole 53 at its radial center. The central hole 53 is a circular hole into which the shaft 60 is fixed by shrink fitting. The shaft 60 is made of, for example, metal.

<Configuration of stator>
The stator 1 has an annular stator core 10 and a winding 20 wound around the stator core 10. The stator core 10 is composed of a plurality of steel plates laminated in the axial direction. The steel plates are, for example, electromagnetic steel plates. The thickness of the steel plates is, for example, 0.1 mm to 1.0 mm.

The stator core 10 has a yoke 11 extending in the circumferential direction and a number of teeth 12 extending radially inward from the yoke 11. The teeth 12 are arranged at equal intervals in the circumferential direction and have tooth tips 12a at their radially inner tips that face the rotor 5. Slots 13, which are areas that accommodate the windings 20, are formed between the circumferentially adjacent teeth 12.

The stator core 10 is formed by connecting multiple split cores 10A in a ring shape. Each split core 10A is a block including one tooth 12. The split cores 10A are joined at a joint surface 14 formed on the yoke 11, for example by welding.

The arc-shaped portion of the yoke 11 that is included in one of the split cores 10A is called the yoke portion 11A. The joint surfaces 14 are formed on both circumferential ends of the yoke portion 11A. The split cores 10A are also called core segments.

The number of teeth 12 is 12 x N (N is a natural number), and the number of slots 13 is also 12 x N. In the example shown in FIG. 1, N = 1. That is, the number of teeth 12 is 12, and the number of slots 13 is also 12. However, N may be 2 or more.

The electric motor 100 of the first embodiment is therefore a 10 x N pole, 12 x N slot electric motor, and as an example, a 10 pole, 12 slot electric motor.

<Winding configuration>
2 is a diagram showing the arrangement of the windings 20 on the stator core 10. The windings 20 are wound in a concentrated manner around each of the teeth 12 of the stator core 10. An insulator 30 (FIG. 9), which will be described later, is arranged between the windings 20 and the stator core 10.

The winding 20 is a collective term for the U-phase winding 20U as the first phase winding, the V-phase winding 20V as the second phase winding, and the W-phase winding 20W as the third phase winding. In each of the

windings

20U, 20V, 20W of each phase, the portion wound around one tooth 12 is referred to as the "winding section."

The U-phase winding 20U has four winding sections U1, U2, U3, and U4. The winding sections U1 and U4 are wound clockwise (CW as shown in FIG. 5) when viewed from the rotor 5 side. On the other hand, the winding sections U2 and U3 are wound counterclockwise (CCW as shown in FIG. 5) when viewed from the rotor 5 side. The winding sections U1 and U4 are also referred to as the U-phase, and the winding sections U2 and U3 are also referred to as the U-bar phase.

The V-phase winding 20V has four winding sections V1, V2, V3, and V4. Winding sections V2 and V3 are wound clockwise when viewed from the rotor 5 side. On the other hand, winding sections V1 and V4 are wound counterclockwise when viewed from the rotor 5 side. Winding sections V2 and V3 are also referred to as the V-phase, and winding sections V1 and V4 are also referred to as the V-bar phase.

The W-phase winding 20W has four winding sections W1, W2, W3, and W4. The winding sections W1 and W4 are wound clockwise when viewed from the rotor 5 side. On the other hand, the winding sections W2 and W3 are wound counterclockwise when viewed from the rotor 5 side. The winding sections W1 and W4 are also referred to as the W-phase, and the winding sections W2 and W3 are also referred to as the W-bar phase.

In the 10 x N pole, 12 x N slot electric motor 100, two winding sections of the same phase but with opposite winding directions are adjacent to each other. For example, the winding sections are arranged in the following order in the circumferential direction: U1, U2, V1, V2, W1, W2, U3, U4, V3, V4, W3, W4. For ease of illustration, in FIG. 2 and FIG. 5 described later, the teeth 12 around which each winding section is wound are given the symbols U1, U2, V1, V2, etc., indicating the winding section.

Each winding section of

windings

20U, 20V, 20W has an inner winding 21 and an outer winding 22 of the same phase. The inner winding 21 is wound around the teeth 12, and the outer winding 22 is wound around the outside of the inner winding 21. For example, winding section U1 has a U-phase inner winding 21 and a U-phase outer winding 22. Winding section U2 has a U-bar phase inner winding 21 and a U-bar phase outer winding 22.

The inner winding 21 and the outer winding 22 wound around the same tooth 12 are wound in the same direction. For example, the inner winding 21 and the outer winding 22 of the winding section U1 are wound clockwise when viewed from the rotor 5 side. Also, the inner winding 21 and the outer winding 22 of the winding section U2 are wound counterclockwise when viewed from the rotor 5 side.

The inner windings 21 of the same phase wound around two adjacent teeth 12 are connected in series. Similarly, the outer windings 22 of the same phase wound around two adjacent teeth 12 are connected in series.

For example, the inner winding 21 of the winding section U1 and the inner winding 21 of the winding section U2 are connected in series via a connection section 41. Also, the outer winding 22 of the winding section U1 and the outer winding 22 of the winding section U2 are connected in series via a connection section 42.

The connection portion 41 is not a jumper wire, but is part of the inner winding 21. In other words, the inner winding 21 of the winding portion U1 extends through the yoke 11 to the adjacent tooth 12, and is wound around that tooth 12 to form the inner winding 21 of the winding portion U2.

In addition, the connection portion 42 is not a jumper wire, but is part of the outer winding 22. In other words, the outer winding 22 of the winding portion U1 extends through the yoke 11 to the adjacent tooth 12, and is wound around that tooth 12 to form the outer winding 22 of the winding portion U2.

Figure 3 is a diagram showing winding sections U1 and U2 wound around two adjacent teeth 12. In Figure 3, the inner winding 21 of winding section U1 is referred to as inner winding section 211, and the inner winding 21 of winding section U2 is referred to as inner winding section 212. Additionally, the outer winding 22 of winding section U1 is referred to as outer winding section 221, and the outer winding 22 of winding section U2 is referred to as outer winding section 222.

Figure 4 is a diagram showing the electrical connection state between the inner winding 21 and the outer winding 22. As shown in Figure 4, the inner winding 21 and the outer winding 22 are connected in parallel. In addition, the inner winding portion 211 of winding portion U1 and the inner winding portion 212 of winding portion U2 are connected in series, and the outer winding portion 221 of winding portion U1 and the outer winding portion 222 of winding portion U2 are also connected in series.

As shown in FIG. 2, the inner winding 21 of winding section V1 and the inner winding 21 of winding section V2 are connected in series via a connection part 41. The outer winding 22 of winding section V1 and the outer winding 22 of winding section V2 are connected in series via a connection part 42. The connection part 41 is part of the inner winding 21, and the connection part 42 is part of the outer winding 22.

In addition, the inner winding 21 of winding section W1 and the inner winding 21 of winding section W2 are connected in series via a connection part 41. In addition, the outer winding 22 of winding section W1 and the outer winding 22 of winding section W2 are connected in series via a connection part 42. The connection part 41 is part of the inner winding 21, and the connection part 42 is part of the outer winding 22.

In addition, winding sections U3, U4, V3, V4, W3, and W4 also have inner windings 21 and outer windings 22 similar to those of winding sections U1 to W2.

The number of turns of the inner winding 21 and the outer winding 22 of each winding section is determined according to the required characteristics of the motor 100 (rotation speed, torque, etc.), the supply voltage, and the cross-sectional area of each slot 13.

FIG. 5 is a diagram showing an example of the connection state of the windings 20 of each phase. In FIG. 5, the outer winding and inner winding of each winding section are shown together with symbols according to the direction of current flow. The winding sections U1, U2 and the winding sections U3, U4 of the U phase are arranged on opposite sides of the axis Ax and are connected to each other by a jumper wire 80U. The jumper wire 80U is a lead wire and extends, for example, between the winding section U2 and the winding section U3.

Furthermore, the V-phase winding sections V1, V2 and the winding sections V3, V4 are arranged on opposite sides of the axis Ax and are connected to each other by a jumper wire 80V. The jumper wire 80V is a lead wire and extends, for example, between the winding section V2 and the winding section V3.

Furthermore, the W-phase windings W1, W2 and W3, W4 are arranged on opposite sides of the axis Ax and are connected to each other by a jumper wire 80W. The jumper wire 80W is a lead wire and extends, for example, between the windings W2 and W3.

In addition, winding sections U4, V4, and W4 are connected to neutral terminal N by jumper wire 81 shown in FIG. 5. U-phase input terminal 82U is connected to winding section U1, V-phase input terminal 82V is connected to winding section V1, and W-phase input terminal 82W is connected to winding section W1. As a result,

windings

20U, 20V, and 20W are connected in a Y-connection.

Note that the wiring example shown in Figure 5 is merely one example, and other wiring connections are possible. For example, a delta connection may be used instead of a wye connection.

FIG. 6 is a diagram showing the

conductors

21a, 22a that make up the inner winding 21 and the outer winding 22. The conductor 21a that makes up the inner winding 21 has a conductor made of copper or aluminum and an insulating coating that covers the conductor. The outer diameter of the conductor portion of the conductor 21a is D1. Because the thickness of the insulating coating is small, the outer diameter D1 can also be considered to be the outer diameter of the conductor 21a.

The conductor 22a that constitutes the outer winding 22 has a conductor made of copper or aluminum and an insulating coating that covers the conductor. The outer diameter of the conductor portion of the conductor 22a is D2. Because the thickness of the insulating coating is small, the outer diameter D2 can also be considered as the outer diameter of the conductor 22a.

The outer diameter D2 of the conductor 22a of the outer winding 22 is larger than the outer diameter D1 of the conductor 21a of the inner winding 21. In other words, the cross-sectional area of the conductor 22a of the outer winding 22 is larger than the cross-sectional area of the conductor 21a of the inner winding 21.

The outer winding 22 is wound further outward than the inner winding 21, and therefore has a longer circumference than the inner winding 21. By making the cross-sectional area of the conductor 22a larger than the cross-sectional area of the conductor 21a as described above, the electrical resistance of the outer winding 22 and the electrical resistance of the inner winding 21 can be made closer to each other.

Note that of the two teeth 12 wound with the inner winding 21 of the same phase and the outer winding 22 of the same phase, one may be referred to as the "first tooth" and the other as the "second tooth." For example, in FIG. 3, the tooth 12 wound with the inner winding 21 and outer winding 22 of the winding section U1 may be referred to as the "first tooth," and the tooth 12 wound with the inner winding 21 and outer winding 22 of the winding section U2 may be referred to as the "second tooth."

<Example of core segment configuration>
As described above, the stator core 10 is divided into 12×N divided cores (core segments) 10A, each of which includes one tooth 12. However, the stator core 10 is not limited to this configuration.

FIG. 7 is a diagram showing a coupled core (core segment) 10B including two teeth 12. The coupled core 10B is formed by combining two of the split cores 10A described above. A split surface 15 is formed on the opposing ends of the yoke portions 11A of the two split cores 10A. A connecting portion 16 that connects the two split cores 10A is formed on the outer periphery of the split surface 15. The connecting portion 16 is, for example, a thin-walled portion.

A joining surface 14 is formed at the end of each yoke portion 11A opposite the dividing surface 15, where the connecting core 10B is joined.

The two teeth 12 of the linked core 10B are wound with windings of the same phase, for example, U-phase windings U1 and U2. The inner winding 21 wound on one tooth 12 and the inner winding 21 wound on the other tooth 12 are connected in series, and the outer winding 22 wound on one tooth 12 and the outer winding 22 wound on the other tooth 12 are connected in series.

The inner winding 21 and outer winding 22 of the same phase can be wound around the two teeth 12 of one connected core 10B, simplifying winding processing and further improving workability. In addition, the number of connected cores 10B that make up the stator core 10 is half the number of teeth 12, or 6 x N, which makes it easier to handle the connected cores 10B and assemble the stator core 10.

Note that although the coupled core 10B shown in FIG. 7 has two teeth 12, the coupled core 10B may have three or more teeth 12.

<Insulator>
Fig. 8 is a perspective view showing the stator 1. Fig. 9 is a view showing a split core 10A of the stator core 10 and an insulator 30 as an insulating part attached thereto. Fig. 10 is a view of the stator 1 as seen from the direction indicated by the arrow A in Fig. 9. Fig. 11 is a view of the stator 1 as seen from the direction indicated by the arrow B in Fig. 9.

As shown in FIG. 9, the insulator 30 has a body portion 33 that surrounds the teeth 12, an outer wall portion 31 located radially outside the body portion 33, and an inner wall portion 32 located radially inside the body portion 33.

The winding 20 (Figure 8) is wound around the body 33. The outer wall 31 guides the winding 20 from the radial outside, and the inner wall 32 guides the winding 20 from the radial inside.

The outer wall portion 31 is formed with a groove portion 31a as a wire passage for passing the windings 20, etc. The outer wall portion 31 is also formed with a holding portion 31b for holding the jumper wires 81, etc. The inner wall portion 32 is formed with

wire guides

32a, 32b for guiding the windings 20, etc.

As shown in FIG. 10, the connection 42 between the outer winding 22 of winding section V3 and the outer winding 22 of winding section V4 extends outside the outer wall section 31. Also, as shown in FIG. 11, the connection 42 between the outer winding 22 of winding section U1 and the outer winding 22 of winding section U2 extends outside the outer wall section 31.

Although only a portion is shown in Figures 9 to 11, the connection portion 41 between the inner windings 21 of the same phase wound around two adjacent teeth 12 extends outside the outer wall portion 31. In addition, the connection portion 42 between the outer windings 22 of the same phase wound around two adjacent teeth 12 also extends outside the outer wall portion 31.

The

crossover wires

80U, 80V, and 80W extend along the inner wall portion 32 or the outer wall portion 31. The crossover wire 81 is held, for example, by a holding portion 31b (FIG. 8) provided on the outer wall portion 31. The

input terminals

82U, 82V, and 82W are attached to the outer wall portion 31.

Note that the arrangement of the

connection parts

41, 42,

jumper wires

80U, 80V, 80W, jumper wire 81, and

input terminals

82U, 82V, 82W described here is merely an example and can be changed as appropriate.

<Stator assembly process>
In the process of assembling the stator 1, steel plates are laminated to form the split cores 10A, and the insulators 30 are attached. Next, as shown in Fig. 3, the split cores 10A are arranged in pairs, and the inner windings 21 of the same phase are wound around the two teeth 12, and the outer windings 22 of the same phase are wound around the inner windings 21.

At this time, the inner winding 21 wound around one tooth 12 is extended to the other tooth 12 and is also wound around the other tooth 12. Also, the outer winding 22 wound around one tooth 12 is extended to the other tooth 12 and is also wound around the other tooth 12.

As a result, the inner windings 21 and the outer windings 22 are wound around the teeth 12 of the two split cores 10A, the inner windings 21 are connected to each other at the connection parts 41, and the outer windings 22 are connected to each other at the connection parts 42.

Then, 12 x N split cores 10A are assembled into a ring shape and joined at the joint surfaces 14 by welding or the like to obtain the stator core 10. Furthermore, the

jumper wires

80U, 80V, 80W and jumper wire 81 shown in FIG. 5 are wired, and

input terminals

82U, 82V, 82W are attached to complete the stator 1.

When using the linked core 10B shown in FIG. 7, steel plates are laminated to form the linked core 10B, and an insulator 30 is attached. Next, the inner winding 21 of the same phase is wound around the two teeth 12 of each linked core 10B, and the outer winding 22 of the same phase is wound around the outer side of that. After that, 6 x N linked cores 10B are assembled into a ring shape and joined at the joint surfaces 14 by welding or the like to obtain the stator core 10. In this case, since the number of linked cores 10B is half the number of teeth 12, handling of the linked cores 10B and assembly of the stator core 10 are made easier.

<Action>
Next, a description will be given of the operation of embodiment 1. In embodiment 1, as shown in Fig. 2, the inner windings 21 wound around two teeth 12 are connected in series, and the outer windings 22 wound around two teeth 12 are also connected in series, and these inner windings 21 and outer windings 22 are connected in parallel.

In this way, the inner winding 21 wound around the two teeth 12 is connected in series, the outer winding 22 is also connected in series, and the inner winding 21 and the outer winding 22 are connected in parallel, so the number of terminals that need to be connected in the inner winding 21 and the outer winding 22 is small. This requires fewer jumper wires, and wiring can be easily performed. This improves workability.

In addition, the inner windings 21 wound around the two teeth 12 are connected in series, and the outer windings 22 are also connected in series, so electrical resistance can be reduced compared to when the inner windings 21 are connected separately for each tooth 12, and the outer windings 22 are also connected separately. As a result, copper loss can be reduced, and motor efficiency can be improved.

In particular, since the number of teeth 12 is 12 x N (N is a natural number) and the number of poles of the rotor 5 is 10 x N, the inner winding 21 of the same phase and the outer winding 22 of the same phase can be wound around two adjacent teeth 12. Therefore, the inner winding 21 and the outer winding 22 can be wound so as not to straddle other teeth 12, and the length of the

connection parts

41, 42 is shortened. This simplifies the process of arranging the

connection parts

41, 42 so as not to interfere with other windings, improving workability.

In addition, because the inner windings 21 wound around the two teeth 12 are connected to each other and the outer windings 22 are connected to each other, there is no need to cross the

connection parts

41, 42, making it easier to arrange the

connection parts

41, 42. As a result, workability is further improved.

In particular, the inner winding 21 wound around one of the two teeth 12 extends to the other tooth 12 and is wound around the other tooth 12 to form the inner winding 21 of the other tooth 12. Also, the outer winding 22 wound around one of the two teeth 12 extends to the other tooth 12 and is wound around the other tooth 12 to form the outer winding 22 of the other tooth 12.

As a result, there is no need to provide a jumper wire connecting the inner windings 21 of the two teeth 12, and a jumper wire connecting the outer windings 22 of the two teeth 12, which reduces the number of parts. In addition, the inner windings 21 and the outer windings 22 can be wound continuously around the two teeth 12, further improving workability.

The outer winding 22 is wound outside the inner winding 21, so it has a longer circumference than the inner winding 21. If the cross-sectional areas of the conductor 21a of the inner winding 21 and the conductor 22a of the outer winding 22 are the same, the electrical resistance of the outer winding 22 (more specifically, the electrical resistance of the conductor 22a) will be greater than the electrical resistance of the inner winding 21 (more specifically, the electrical resistance of the conductor 21a). If the electrical resistances of the inner winding 21 and the outer winding 22 differ, a circulating current will flow when the two are connected in parallel due to the difference in voltage drop, which may increase copper loss.

By making the cross-sectional area of the conductor 22a of the outer winding 22 larger than the cross-sectional area of the conductor 21a of the inner winding 21 (see Figure 6), the electrical resistance of the outer winding 22 and the electrical resistance of the inner winding 21 can be made closer to each other, improving the imbalance in electrical resistance. This makes it possible to suppress the generation of circulating currents when the inner winding 21 and the outer winding 22 are connected in parallel, and to reduce copper loss.

The stator core 10 is made by combining 12 x N split cores 10A, each with one tooth 12, in the circumferential direction. Therefore, the split cores 10A are lined up in pairs (see Figure 3), and the same-phase inner winding 21 and the same-phase outer winding 22 are wound around the teeth 12. The stator core 10 is then obtained by assembling the 12 x N split cores 10A into a ring shape. This further improves workability.

In addition, when the stator core 10 is a circumferential combination of 6 x N connected cores 10B, each having two teeth 12 (see FIG. 7), the inner winding 21 of the same phase and the outer winding 22 of the same phase are wound around the two teeth 12 of each connected core 10B, and then the 6 x N connected cores 10B are assembled into a ring shape to obtain the stator core 10. Because the number of connected cores 10B is half the number of teeth 12, handling of the connected cores 10B and assembly of the stator core 10 are made easier, further improving workability.

In addition, the connection 41 between the inner winding 21 wound around the two teeth 12 and the connection 42 between the outer winding 22 wound around the two teeth 12 are wound along the insulator 30 attached to the stator core 10, so that the

connection

41, 42 can be routed so as not to protrude radially outward from the stator core 10.

<Effects of the embodiment>
As described above, the stator 1 of the first embodiment is a stator 1 that constitutes an electric motor 100 together with the rotor 5 having 10×N magnetic poles (N is a natural number), and has an annular stator core 10 on which 12×N teeth 12 are arranged in the circumferential direction, an inner winding 21 wound around each of the 12×N teeth 12, and an outer winding 22 wound around the inner winding 21. The inner winding 21 and the outer winding 22 are connected in parallel, and the inner winding 21 wound around one tooth 12 (first tooth) and the inner winding 21 wound around the other tooth 12 (second tooth) of the two teeth 12 are connected in series, and the outer winding 22 wound around the one tooth 12 and the outer winding 22 wound around the other tooth 12 are connected in series.

This configuration reduces the number of terminals that require wiring work, simplifies the wiring work, and improves workability. In addition, the inner windings 21 wound around the two teeth 12 are connected in series, and the outer windings 22 are connected in series, so the electrical resistance of the inner windings 21 and the outer windings 22 can be reduced. This reduces copper loss and improves motor efficiency.

In particular, since the number of teeth 12 is 12 x N and the number of poles of the rotor 5 is 10 x N, it is possible to wind the inner winding 21 of the same phase and the outer winding 22 of the same phase around two adjacent teeth 12. The inner winding 21 and the outer winding 22 can be wound without straddling other teeth 12, further improving workability.

<Modifications, etc.>
The first embodiment described above can be modified as appropriate. For example, in the above configuration, the inner windings 21 wound around two adjacent teeth 12 are connected in series, and the outer windings 22 wound around two adjacent teeth 12 are connected in series, but the two teeth 12 do not necessarily have to be adjacent to each other.

For example, the inner windings 21 wound around two adjacent teeth 12 on either side of one tooth 12 may be connected in series, and the outer windings 22 wound around the two adjacent teeth 12 may be connected in series.

In addition, in the above configuration, the connection portion 41 is part of the inner winding 21, and the connection portion 42 is part of the outer winding 22, but the connection portion 41 may be formed of a lead wire that is a separate member from the inner winding 21, and the connection portion 42 may be formed of a lead wire that is a separate member from the outer winding 22.

In addition, in the above configuration, the cross-sectional area of the conductor 22a of the outer winding 22 is larger than the cross-sectional area of the conductor 21a of the inner winding 21, but the cross-sectional areas may be reversed, or the cross-sectional areas may be the same.

<Compressor>
Next, a compressor 300 to which the electric motor 100 can be applied will be described. Fig. 12 is a vertical cross-sectional view showing the compressor 300 equipped with the electric motor 100. The compressor 300 is a rotary compressor in this example, but may be a scroll compressor.

The compressor 300 includes a sealed container 307, a compression mechanism 301 disposed within the sealed container 307, and an electric motor 100 that drives the compression mechanism 301.

The compression mechanism 301 has a cylinder 302 with a cylinder chamber 303, a rolling piston 304 fixed to the shaft 60 of the electric motor 100, a vane that divides the inside of the cylinder chamber 303 into an intake side and a compression side, and an upper frame 305 and a lower frame 306 into which the shaft 60 is inserted and which close the axial end faces of the cylinder chamber 303. An upper discharge muffler 308 and a lower discharge muffler 309 are attached to the upper frame 305 and the lower frame 306, respectively.

The sealed container 307 is a cylindrical container. Refrigeration oil (not shown) that lubricates each sliding part of the compression mechanism 301 is stored in the bottom of the sealed container 307. The shaft 60 is rotatably supported by the upper frame 305 and the lower frame 306, which serve as bearings.

The cylinder 302 has a cylinder chamber 303 inside, and the rolling piston 304 rotates eccentrically within the cylinder chamber 303. The shaft 60 has an eccentric shaft portion, and the rolling piston 304 is fitted into the eccentric shaft portion.

The stator 1 of the electric motor 100 is assembled inside the sealed container 307 by a method such as shrink fitting, press fitting, or welding. Power is supplied to the windings 20 of the stator 1 from glass terminals 311 fixed to the sealed container 307. The shaft 60 is fixed to the rotor core 50 as described above.

An accumulator 310 is attached to the outside of the sealed container 307. Refrigerant gas flows into the accumulator 310 from the refrigerant circuit via a suction pipe 314. When liquid refrigerant flows in together with the refrigerant gas from the suction pipe 314, the liquid refrigerant is stored in the accumulator 310, and the refrigerant gas is supplied to the compressor 300.

A suction pipe 313 is fixed to the sealed container 307, and refrigerant gas is supplied from the accumulator 310 to the cylinder 302 via this suction pipe 313. In addition, a discharge pipe 312 that discharges the refrigerant to the outside is provided at the top of the sealed container 307.

The refrigerant for the compressor 300 may be, for example, R410A, R407C, or R22, but from the perspective of preventing global warming, it is preferable to use a refrigerant with a low GWP (global warming potential). For example, the following refrigerants can be used as refrigerants with a low GWP.

(1) First, a halogenated hydrocarbon having a carbon double bond in its composition, such as HFO (Hydro-Fluoro-Orefin)-1234yf (CF ₃ CF═CH ₂ ), can be used. The GWP of HFO-1234yf is 4.
(2) Hydrocarbons having carbon double bonds in their composition, such as R1270 (propylene), may also be used. R1270 has a GWP of 3, which is lower than HFO-1234yf, but is more flammable than HFO-1234yf.
(3) Also, a mixture containing at least one of a halogenated hydrocarbon having a carbon-carbon double bond in its composition or a hydrocarbon having a carbon-carbon double bond in its composition, for example, a mixture of HFO-1234yf and R32 may be used. The above-mentioned HFO-1234yf is a low-pressure refrigerant and tends to cause large pressure loss, which may lead to a decrease in the performance of the refrigeration cycle (especially the evaporator). For this reason, it is practically desirable to use a mixture of HFO-1234yf and R32 or R41, which are refrigerants at higher pressures than HFO-1234yf.

The operation of the compressor 300 is as follows. Refrigerant gas supplied from the accumulator 310 is supplied through the suction pipe 313 into the cylinder chamber 303 of the cylinder 302. When the electric motor 100 is driven by supplying current to the windings 20, the shaft 60 rotates together with the rotor 5. Then, the rolling piston 304 fitted to the shaft 60 rotates eccentrically within the cylinder chamber 303, compressing the refrigerant within the cylinder chamber 303.

The refrigerant compressed in the cylinder chamber 303 passes through the discharge mufflers 308 and 309, and then through the gap or through-hole (not shown) between the rotor 5 and the stator 1, and rises inside the sealed container 307. The refrigerant that has risen inside the sealed container 307 is discharged from the discharge pipe 312 and supplied to the high-pressure side of the refrigeration cycle.

The electric motor 100 of the first embodiment has high motor efficiency due to the reduced electrical resistance of the windings 20. Therefore, by using the electric motor 100 as the driving source of the compressor 300, the operating efficiency of the compressor 300 can be improved.

The compressor 300 shown in FIG. 12 is a single rotary compressor having a single cylinder 302, but it may also be a twin rotary compressor having two cylinders with opposite eccentric directions. The electric motor 100 of the first embodiment can improve the operating efficiency when used in any type of compressor.

<Refrigeration cycle device>
Next, a refrigeration cycle apparatus 400 having the compressor 300 shown in Fig. 12 will be described. Fig. 13 is a diagram showing the refrigeration cycle apparatus 400. The refrigeration cycle apparatus 400 is, for example, an air conditioner, but is not limited thereto, and may be, for example, a refrigerator.

The refrigeration cycle device 400 shown in FIG. 13 includes a compressor 401, a condenser 402 that condenses the refrigerant, a pressure reducing device 403 that reduces the pressure of the refrigerant, and an evaporator 404 that evaporates the refrigerant. The compressor 401, the condenser 402, and the pressure reducing device 403 are provided in the outdoor unit 410, and the evaporator 404 is provided in the indoor unit 420.

The compressor 401, condenser 402, pressure reducing device 403, and evaporator 404 are connected by refrigerant piping 407 to form a refrigerant circuit. The compressor 401 is formed by the compressor 300 shown in FIG. 12. The refrigeration cycle device 400 also includes an outdoor blower 405 facing the condenser 402, and an indoor blower 406 facing the evaporator 404.

The operation of the refrigeration cycle device 400 is as follows. The compressor 401 compresses the sucked refrigerant and sends it out as high-temperature, high-pressure refrigerant gas. The condenser 402 exchanges heat between the refrigerant sent out from the compressor 401 and the outdoor air sent by the outdoor blower 405, condenses the refrigerant, and sends it out as liquid refrigerant. The pressure reducing device 403 expands the liquid refrigerant sent out from the condenser 402, and sends it out as low-temperature, low-pressure liquid refrigerant.

The evaporator 404 exchanges heat between the low-temperature, low-pressure liquid refrigerant sent from the pressure reducing device 403 and the indoor air, evaporating the refrigerant and sending it out as refrigerant gas. The air from which the heat has been removed by the evaporator 404 is supplied by the indoor blower 406 to the room, which is the space to be air-conditioned.

The compressor 401 of the refrigeration cycle device 400 is equipped with the electric motor 100 of the first embodiment, and the electric motor 100 has high motor efficiency. Therefore, by using the electric motor 100 as the driving source of the compressor 300 of the refrigeration cycle device 400, the operating efficiency of the refrigeration cycle device 400 can be improved.

The above describes a preferred embodiment in detail, but the present disclosure is not limited to the above embodiment, and various improvements and modifications can be made.

LIST OF SYMBOLS 1 stator, 5 rotor, 10 stator core, 10A split core (core segment), 10B connected core (core segment), 11 yoke, 12 teeth (first teeth, second teeth), 13 slot, 14 joint surface, 15 split surface, 16 connection portion, 20 winding, 20U U-phase winding, 20V V-phase winding, 20W W-phase winding, 21 inner winding, 21a conductor, 22 outer winding, 22a conductor, 30 insulator (insulating portion), 31 outer wall portion, 32 inner wall portion, 33 body portion, 41 connection portion, 42 connection portion, 50 rotor core, 51 magnet insertion hole, 55 permanent magnet, 60 shaft, 80U, 80V, 80W Crossover wire, 81 crossover wire, 82U, 82V, 82W input terminal, 100 electric motor, 300 compressor, 301 compression mechanism, 307 sealed container, 400 refrigeration cycle device, 401 compressor, 402 condenser, 403 pressure reducing device, 404 evaporator, U1, U2, U3, U4 winding section, V1, V2, V3, V4 winding section, W1, W2, W3, W4 winding section.

Claims

A stator constituting an electric motor together with a rotor having 10×N magnetic poles (N is a natural number),
An annular stator core having 12×N teeth arranged in a circumferential direction;
An inner winding is wound around each of the 12×N teeth, and an outer winding is wound around the outer side of the inner winding,
the inner winding and the outer winding are connected in parallel;
an inner winding wound around a first tooth and an inner winding wound around a second tooth of the 12×N teeth are connected in series;
a stator in which an outer winding wound around the first teeth and an outer winding wound around the second teeth are connected in series.
2. The stator according to claim 1, wherein the inner winding wound around the first teeth extends to the second teeth and is wound around the second teeth to form the inner winding wound around the second teeth.
3. The stator according to claim 1, wherein the outer winding wound around the first teeth extends to the second teeth and is wound around the second teeth to form the outer winding wound around the second teeth.
The stator according to claim 1 , wherein the first teeth and the second teeth are adjacent to each other in the circumferential direction.
5. The stator according to claim 1, wherein a cross-sectional area of a conductor constituting the outer winding is larger than a cross-sectional area of a conductor constituting the inner winding.
The stator according to claim 1 , wherein the stator core is formed by combining a plurality of split cores, each of which has at least one tooth, in the circumferential direction.
The stator according to claim 1 , wherein the stator core is formed by combining a plurality of coupled cores, each of which has at least two teeth, in the circumferential direction.
The stator according to claim 7 , wherein the inner winding of the same phase and the outer winding of the same phase are wound on the at least two teeth of each connecting core.
Further comprising an insulation portion attached to the stator core;
9. The stator according to claim 1, wherein a portion between the inner winding wound around the first teeth and the inner winding wound around the second teeth is wound along the insulating portion.
A stator according to any one of claims 1 to 9;
The rotor is rotatably provided inside the stator.
An electric motor according to claim 10;
a compression mechanism driven by the electric motor.
A refrigeration cycle apparatus comprising the compressor according to claim 11, a condenser, a pressure reducing device, and an evaporator.