Stator, electric motor, compressor and refrigeration cycle apparatus

JPWO2024089866A5Inactive Publication Date: 2025-04-30

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Patent Information

Application Number: JP2024552631
Authority / Receiving Office: JP · JP
Patent Type: Applications
Filing Date: 2025-02-20
Publication Date: 2025-04-30
Estimated Expiration: Not applicable · inactive patent

AI Technical Summary

Technical Problem

Conventional electric motor stators require complex and lengthy wiring due to numerous crossover wires, leading to low workability and efficiency.

Method used

The stator design features an annular core with 12×N teeth, where inner and outer windings are connected in parallel and series configurations, simplifying wiring and reducing electrical resistance, thereby improving workability and motor efficiency.

Benefits of technology

This configuration reduces copper loss, enhances motor efficiency, and simplifies the winding process by minimizing the number of crossover wires and terminals, improving overall workability and performance.

✦ Generated by Eureka AI based on patent content.

Patent Text Reader

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.

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Description

Stator, electric motor, compressor and refrigeration cycle device

[0001] The present disclosure relates to a stator, an electric motor, a compressor, and a refrigeration cycle device.

[0002] The stator of an electric motor has a stator core and a winding. The stator core has a plurality of teeth, and slots are formed between adjacent teeth. The winding is wound around the teeth and housed in the slots.

[0003] For example, Patent Document 1 discloses 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 are wound in a concentrated manner on the teeth on both sides, skipping two teeth. The second three-phase winding is wound in a similar manner.

[0004] JP 2008-193785 A (see FIGS. 5 and 7)

[0005] However, in the conventional technology, many jumper wires are required to connect the winding sections, and the jumper wires are long. As a result, complex wiring is required to avoid interference between the winding sections and the jumper wires, resulting in a problem of low workability.

[0006] The present disclosure has been made to solve the above-mentioned problems, and aims to simplify the connection of windings and improve workability.

[0007] The stator of the present disclosure is a stator that constitutes an electric motor together with a rotor having 10×N (N is a natural number) magnetic poles. 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 around the inner winding. The inner winding and the outer winding are connected in parallel. Of the 12×N teeth, the inner winding wound on a first tooth and the inner winding wound on a 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.

[0008] 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, which simplifies wiring and improves workability.

[0009] 12 is a cross-sectional view showing an electric motor according to a first embodiment; FIG. 13 is a cross-sectional view showing the arrangement of windings in a stator according to the first embodiment; FIG. 14 is a view showing winding portions wound around two teeth of the stator according to the first embodiment; FIG. 15 is a view showing a connection state between an inner winding and an outer winding according to the first embodiment; FIG. 16 is a view showing a connection state of winding portions of each phase according to the first embodiment; FIG. 17 is a view showing conductors constituting the inner winding and the outer winding according to the first embodiment; FIG. 18 is a view showing another configuration example of a core segment according to the first embodiment; FIG. 19 is a perspective view showing a stator according to the first embodiment; FIG. 19 is a perspective view showing a core segment and an insulator according to the first embodiment; FIG. 19 is a perspective view showing a part of the stator according to the first embodiment; FIG. 20 is a perspective view showing a part of the stator according to the first embodiment, different from FIG. 10; FIG. 21 is a longitudinal cross-sectional view showing a compressor to which the electric motor according to the first embodiment can be applied; FIG. 22 is a view showing a refrigeration cycle device including the compressor of FIG.

[0010] 1 is a cross-sectional view showing an electric motor 100 according to embodiment 1. The electric motor 100 includes a rotor 5 and an annular stator 1 that surrounds the rotor 5. An air gap is provided between the stator 1 and the rotor 5.

[0011] 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."

[0012] <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 up of a plurality of steel plates stacked 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.

[0013] A plurality 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×N (N is a natural number). The magnet insertion holes 51 are formed at equal intervals in the circumferential direction. One flat plate-shaped permanent magnet 55 is inserted into each magnet insertion hole 51.

[0014] The permanent magnets 55 are made of rare earth magnets, such as 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.

[0015] The permanent magnet 55 arranged in each magnet insertion hole 51 constitutes one magnetic pole. Since the number of magnet insertion holes 51 is 10×N, the number of poles of the rotor 5 is 10×N.

[0016] 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.

[0017] 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 in a V-shape, for example.

[0018] The rotor core 50 has a center hole 53 at its radial center. The center 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.

[0019] <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 made up of a plurality of steel plates stacked 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.

[0020] The stator core 10 has a yoke 11 extending in the circumferential direction and a plurality 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 for accommodating windings 20, are formed between adjacent teeth 12 in the circumferential direction.

[0021] The stator core 10 is formed by connecting a plurality of split cores 10A in an annular shape. Each split core 10A is a block including one tooth 12. The split cores 10A are joined to the yoke 11 at a joining surface 14 formed on the yoke 11 by, for example, welding.

[0022] The arc-shaped portions of the yoke 11 included in one of the split cores 10A are referred to as yoke portions 11A. The joining surfaces 14 are formed on both circumferential ends of the yoke portion 11A. The split cores 10A are also referred to as core segments.

[0023] The number of teeth 12 is 12×N (N is a natural number), and the number of slots 13 is also 12×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.

[0024] Therefore, the electric motor 100 of the first embodiment is a 10×N pole, 12×N slot electric motor, and as an example, a 10 pole, 12 slot electric motor.

[0025] <Winding Configuration> Fig. 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 tooth 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.

[0026] The winding 20 is a collective term for a U-phase winding 20U as a first-phase winding, a V-phase winding 20V as a second-phase winding, and a W-phase winding 20W as a third-phase winding. In each of the windings 20U, 20V, and 20W of each phase, the portion wound around one tooth 12 is referred to as a "winding portion."

[0027] The U-phase winding 20U has four winding portions U1, U2, U3, and U4. The winding portions U1 and U4 are wound clockwise (CW as shown in FIG. 5) as viewed from the rotor 5 side. On the other hand, the winding portions U2 and U3 are wound counterclockwise (CCW as shown in FIG. 5) as viewed from the rotor 5 side. The winding portions U1 and U4 are also referred to as the U-phase, and the winding portions U2 and U3 are also referred to as the U-bar phase.

[0028] The V-phase winding 20V has four winding portions V1, V2, V3, and V4. The winding portions V2 and V3 are wound clockwise when viewed from the rotor 5 side. On the other hand, the winding portions V1 and V4 are wound counterclockwise when viewed from the rotor 5 side. The winding portions V2 and V3 are also referred to as the V-phase, and the winding portions V1 and V4 are also referred to as the V-bar phase.

[0029] The W-phase winding 20W has four winding portions W1, W2, W3, and W4. The winding portions W1 and W4 are wound clockwise when viewed from the rotor 5 side. On the other hand, the winding portions W2 and W3 are wound counterclockwise when viewed from the rotor 5 side. The winding portions W1 and W4 are also referred to as the W-phase, and the winding portions W2 and W3 are also referred to as the W-bar phase.

[0030] In the 10×N pole, 12×N slot electric motor 100, two winding portions of the same phase but with opposite winding directions are adjacent to each other. For example, the winding portions are arranged in the following order circumferentially: U1, U2, V1, V2, W1, W2, U3, U4, V3, V4, W3, W4. For convenience of illustration, in FIG. 2 and FIG. 5 described later, the teeth 12 around which each winding portion is wound are labeled with the symbols U1, U2, V1, V2, etc., indicating the winding portion.

[0031] Each winding section of the windings 20U, 20V, and 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 inner winding 21. For example, the winding section U1 has a U-phase inner winding 21 and a U-phase outer winding 22. The winding section U2 has a U-bar phase inner winding 21 and a U-bar phase outer winding 22.

[0032] 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.

[0033] 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.

[0034] 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 connecting portion 41. Furthermore, 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 connecting portion 42.

[0035] The connection portion 41 is not a crossover wire but is part of the inner winding 21. That is, 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.

[0036] Furthermore, the connection portion 42 is not a crossover wire but is part of the outer winding 22. That is, 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.

[0037] 3 is a diagram showing winding portions U1 and U2 wound around two adjacent teeth 12. In Fig. 3, the inner winding 21 of winding portion U1 is referred to as inner winding portion 211, and the inner winding 21 of winding portion U2 is referred to as inner winding portion 212. Furthermore, the outer winding 22 of winding portion U1 is referred to as outer winding portion 221, and the outer winding 22 of winding portion U2 is referred to as outer winding portion 222.

[0038] Fig. 4 is a diagram showing the electrical connection state between the inner winding 21 and the outer winding 22. As shown in Fig. 4, the inner winding 21 and the outer winding 22 are connected in parallel. Furthermore, the inner winding portion 211 of the winding portion U1 and the inner winding portion 212 of the winding portion U2 are connected in series, and the outer winding portion 221 of the winding portion U1 and the outer winding portion 222 of the winding portion U2 are also connected in series.

[0039] 2 , the inner winding 21 of the winding section V1 and the inner winding 21 of the winding section V2 are connected in series via a connection 41. Furthermore, the outer winding 22 of the winding section V1 and the outer winding 22 of the winding section V2 are connected in series via a connection 42. The connection 41 is a part of the inner winding 21, and the connection 42 is a part of the outer winding 22.

[0040] The inner winding 21 of the winding portion W1 and the inner winding 21 of the winding portion W2 are connected in series via a connecting portion 41. The outer winding 22 of the winding portion W1 and the outer winding 22 of the winding portion W2 are connected in series via a connecting portion 42. The connecting portion 41 is a part of the inner winding 21, and the connecting portion 42 is a part of the outer winding 22.

[0041] Similarly, the winding sections U3, U4, V3, V4, W3, and W4 each have an inner winding 21 and an outer winding 22 similar to the winding sections U1 and W2.

[0042] 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 (rotation speed, torque, etc.) of the electric motor 100 , the supply voltage, and the cross-sectional area of each slot 13 .

[0043] Fig. 5 is a diagram showing an example of the connection state of the windings 20 of each phase. In Fig. 5, the outer and inner windings of each winding section are indicated by symbols corresponding to the direction of current flow. The winding sections U1 and U2 of the U phase and the winding sections U3 and U4 are arranged on opposite sides of the axis Ax and are connected to each other by a crossover wire 80U. The crossover wire 80U is a lead wire that extends, for example, between the winding section U2 and the winding section U3.

[0044] Furthermore, the V-phase winding portions V1 and V2 and the V-phase winding portions V3 and V4 are disposed on opposite sides of the axis Ax and are connected to each other by a crossover wire 80 V. The crossover wire 80 V is a lead wire and extends, for example, between the winding portion V2 and the winding portion V3.

[0045] The W-phase windings W1, W2 and W3, W4 are disposed on opposite sides of the axis Ax and are connected to each other by a crossover wire 80W. The crossover wire 80W is a lead wire and extends, for example, between the windings W2 and W3.

[0046] Winding portions U4, V4, and W4 are connected to a neutral terminal N by a crossover wire 81 shown in Fig. 5. A U-phase input terminal 82U is connected to winding portion U1, a V-phase input terminal 82V is connected to winding portion V1, and a W-phase input terminal 82W is connected to winding portion W1. As a result, windings 20U, 20V, and 20W are connected in a Y-connection.

[0047] 5 is merely an example, and other connections are possible. For example, a delta connection may be used instead of the wye connection.

[0048] 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 conductor portion of the conductor 21a has an outer diameter D1. Because the insulating coating is only slightly thick, the outer diameter D1 can also be considered to be the outer diameter of the conductor 21a.

[0049] The conductor 22a constituting the outer winding 22 has a conductor made of copper or aluminum and an insulating coating covering the conductor. The conductor portion of the conductor 22a has an outer diameter 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.

[0050] 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. That is, 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.

[0051] The outer winding 22 is wound more outward than the inner winding 21, and therefore has a longer circumferential length 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.

[0052] Note that, of 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.”

[0053] <Configuration Example of Core Segments> As described above, the stator core 10 is divided into 12×N divided cores (core segments) 10A, each including one tooth 12. However, the stator core 10 is not limited to this configuration.

[0054] 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 dividing surface 15 is formed at 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 dividing surface 15. The connecting portion 16 is, for example, a thin-walled portion.

[0055] At the end of each yoke portion 11A opposite to the dividing surface 15, a joining surface 14 is formed to be joined to another couple core 10B.

[0056] Windings of the same phase, for example, U-phase windings U1 and U2, are wound around the two teeth 12 of the coupled core 10B. The inner winding 21 wound around one tooth 12 and the inner winding 21 wound around the other tooth 12 are connected in series, and the outer winding 22 wound around one tooth 12 and the outer winding 22 wound around the other tooth 12 are connected in series.

[0057] Since the inner winding 21 and outer winding 22 of the same phase can be wound around the two teeth 12 of one coupled core 10B, winding processing is simplified and workability is further improved. In addition, the number of coupled cores 10B constituting the stator core 10 is 6 × N, which is half the number of teeth 12, making it easier to handle the coupled cores 10B and assemble the stator core 10.

[0058] Although the coupler core 10B shown in FIG. 7 has two teeth 12, the coupler core 10B may have three or more teeth 12.

[0059] <Insulator> Fig. 8 is a perspective view showing the stator 1. Fig. 9 is a view showing split cores 10A of the stator core 10 and insulators 30 attached thereto as insulating parts. Fig. 10 is a view of the stator 1 as seen from the direction indicated by arrow A in Fig. 9. Fig. 11 is a view of the stator 1 as seen from the direction indicated by arrow B in Fig. 9.

[0060] As shown in FIG. 9 , the insulator 30 has a body portion 33 surrounding the teeth 12 , an outer wall portion 31 positioned radially outside the body portion 33 , and an inner wall portion 32 positioned radially inside the body portion 33 .

[0061] The winding 20 (FIG. 8) is wound around the body 33. The outer wall 31 guides the winding 20 from the outside in the radial direction, and the inner wall 32 guides the winding 20 from the inside in the radial direction.

[0062] Groove portions 31a are formed in the outer wall portion 31 as wire passages through which the windings 20 and the like pass. Also formed in the outer wall portion 31 are holding portions 31b that hold the crossover wires 81 and the like. Wire guides 32a and 32b that guide the windings 20 and the like are formed in the inner wall portion 32.

[0063] 10, the connection 42 between the outer winding 22 of the winding section V3 and the outer winding 22 of the winding section V4 extends outside the outer wall 31. Also, as shown in FIG. 11, the connection 42 between the outer winding 22 of the winding section U1 and the outer winding 22 of the winding section U2 extends outside the outer wall 31.

[0064] 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.

[0065] 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 by, for example, 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.

[0066] The arrangement of the connection parts 41, 42, crossover wires 80U, 80V, 80W, crossover wire 81, and input terminals 82U, 82V, 82W described here is merely an example and can be changed as appropriate.

[0067] <Stator Assembly Process> In the assembly process of the stator 1, steel plates are stacked to form the split cores 10A, and the insulators 30 are attached. Next, as shown in Fig. 3 , the split cores 10A are lined up 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.

[0068] 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. In addition, 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.

[0069] This results in a configuration in which 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 portions 41, and the outer windings 22 are connected to each other at the connection portions 42.

[0070] Thereafter, 12×N split cores 10A are assembled into a ring shape and joined at joint surfaces 14 by welding or the like to obtain stator core 10. Furthermore, crossover wires 80U, 80V, 80W and crossover wire 81 shown in FIG. 5 are wired, and input terminals 82U, 82V, 82W are attached, thereby completing stator 1.

[0071] 7 is used, the coupled core 10B is formed by stacking steel plates, and an insulator 30 is attached. Next, the inner winding 21 of the same phase is wound around the two teeth 12 of each coupled core 10B, and the outer winding 22 of the same phase is wound around the inner winding 21. Thereafter, 6×N coupled cores 10B are assembled into a ring shape and joined at the joint surfaces 14 by welding or the like, thereby obtaining the stator core 10. In this case, because the number of coupled cores 10B is half the number of teeth 12, handling of the coupled core 10B and assembly of the stator core 10 are facilitated.

[0072] <Function> Next, a description will be given of the function 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.

[0073] In this way, the inner windings 21 wound around the two teeth 12 are connected in series, the outer windings 22 are also connected in series, and the inner windings 21 and outer windings 22 are connected in parallel, so the number of terminals that need to be connected in the inner windings 21 and outer windings 22 is small. This means that the number of jumper wires required is small, making wiring easier. This improves workability.

[0074] Furthermore, because the inner windings 21 wound around the two teeth 12 are connected in series, and the outer windings 22 are also connected in series, electrical resistance can be reduced compared to when the inner windings 21 and outer windings 22 are connected separately for each tooth 12. As a result, copper loss can be reduced, and motor efficiency can be improved.

[0075] In particular, since the number of teeth 12 is 12×N (N is a natural number) and the number of poles of the rotor 5 is 10×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. This allows the inner winding 21 and the outer winding 22 to be wound so as not to straddle other teeth 12, thereby shortening the lengths of the connecting portions 41, 42. This simplifies the process of arranging the connecting portions 41, 42 so as not to interfere with other windings, improving workability.

[0076] Furthermore, since 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 connecting portions 41, 42, which makes it easier to arrange the connecting portions 41, 42. As a result, workability is further improved.

[0077] 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. Furthermore, 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.

[0078] Therefore, it is not necessary to provide a crossover wire connecting the inner windings 21 of the two teeth 12 and a crossover wire connecting the outer windings 22 of the two teeth 12, thereby reducing the number of parts. In addition, the inner winding 21 and the outer winding 22 can be wound continuously around the two teeth 12, further improving workability.

[0079] Because the outer winding 22 is wound outside the inner winding 21, it has a longer circumferential length 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 they are connected in parallel due to the difference in voltage drop, which may increase copper loss.

[0080] 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 FIG. 6), the electrical resistance of the outer winding 22 and the electrical resistance of the inner winding 21 are made closer to each other, thereby improving the imbalance in electrical resistance. This makes it possible to suppress the generation of circulating current when the inner winding 21 and the outer winding 22 are connected in parallel, and reduce copper loss.

[0081] The stator core 10 is formed by combining 12×N split cores 10A in the circumferential direction, each having one tooth 12. Therefore, the split cores 10A are arranged in pairs (see FIG. 3), and the inner winding 21 of the same phase and the outer winding 22 of the same phase are wound around the teeth 12. The stator core 10 is then obtained by assembling the 12×N split cores 10A into a ring shape. This further improves workability.

[0082] Furthermore, when the stator core 10 is formed by combining 6×N connected cores 10B, each having two teeth 12, in the circumferential direction (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×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.

[0083] Furthermore, the connection portion 41 between the inner winding 21 wound around the two teeth 12 and the connection portion 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 portions 41, 42 can be routed so as not to protrude radially outward from the stator core 10.

[0084] <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 includes 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 of the two teeth 12, the inner winding 21 wound around one tooth 12 (first tooth) and the inner winding 21 wound around the other tooth 12 (second tooth) 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.

[0085] This configuration reduces the number of terminals that require wiring work, simplifies the wiring work, and improves workability. Furthermore, because the inner windings 21 wound around the two teeth 12 are connected in series, and the outer windings 22 are connected in series, it is possible to reduce the electrical resistance of the inner windings 21 and the outer windings 22. This reduces copper loss and improves motor efficiency.

[0086] In particular, since the number of teeth 12 is 12×N and the number of poles of the rotor 5 is 10×N, the inner winding 21 and the outer winding 22 of the same phase can be wound 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.

[0087] <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.

[0088] For example, the inner windings 21 wound around two adjacent teeth 12 sandwiching one tooth 12 may be connected in series, and the outer windings 22 wound around the two teeth 12 may be connected in series.

[0089] Furthermore, 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. However, 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.

[0090] 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 may be the same.

[0091] <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 also be a scroll compressor.

[0092] The compressor 300 includes a sealed container 307 , a compression mechanism 301 disposed in the sealed container 307 , and an electric motor 100 that drives the compression mechanism 301 .

[0093] The compression mechanism 301 has a cylinder 302 having a cylinder chamber 303, a rolling piston 304 fixed to the shaft 60 of the electric motor 100, a vane that divides the interior 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.

[0094] The sealed container 307 is a cylindrical container. Refrigerating machine oil (not shown) that lubricates the sliding parts of the compression mechanism 301 is stored in the bottom of the sealed container 307. The shaft 60 is rotatably held by an upper frame 305 and a lower frame 306 that serve as bearings.

[0095] The cylinder 302 has a cylinder chamber 303 therein, 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 onto the eccentric shaft portion.

[0096] 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. Electric 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.

[0097] 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.

[0098] 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 is provided at the top of the sealed container 307 to discharge the refrigerant to the outside.

[0099] The refrigerant used in the compressor 300 may be, for example, R410A, R407C, or R22. However, from the perspective of preventing global warming, it is desirable 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:

[0100] (1) First, a halogenated hydrocarbon having a carbon-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) Alternatively, a hydrocarbon having a carbon-carbon double bond in its composition, such as R1270 (propylene), may be used. The GWP of R1270 is 3, which is lower than that of HFO-1234yf, but its flammability is higher than that of HFO-1234yf. (3) Alternatively, a mixture containing at least one halogenated hydrocarbon having a carbon-carbon double bond in its composition or a hydrocarbon having a carbon-carbon double bond in its composition, such as a mixture of HFO-1234yf and R32, may be used. The above-mentioned HFO-1234yf is a low-pressure refrigerant and therefore tends to cause large pressure loss, which may lead to a decrease in the performance of the refrigeration cycle (especially the evaporator). Therefore, it is practically desirable to use a mixture of HFO-1234yf with R32 or R41, which are higher-pressure refrigerants than HFO-1234yf.

[0101] 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 winding 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.

[0102] The refrigerant compressed in the cylinder chamber 303 passes through discharge mufflers 308 and 309, and then passes 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 a discharge pipe 312 and supplied to the high-pressure side of the refrigeration cycle.

[0103] Electric motor 100 of the first embodiment has high motor efficiency due to the reduced electrical resistance of windings 20. Therefore, by using electric motor 100 as the drive source of compressor 300, the operating efficiency of compressor 300 can be improved.

[0104] 12 is a single rotary compressor having a single cylinder 302, but 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.

[0105] <Refrigeration cycle device> Next, a refrigeration cycle device 400 having the compressor 300 shown in Fig. 12 will be described. Fig. 13 is a diagram showing the refrigeration cycle device 400. The refrigeration cycle device 400 is, for example, an air conditioner, but is not limited thereto and may be, for example, a refrigerator.

[0106] 13 includes a compressor 401, a condenser 402 that condenses a 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 an outdoor unit 410, and the evaporator 404 is provided in an indoor unit 420.

[0107] The compressor 401, the condenser 402, the pressure reducing device 403, and the evaporator 404 are connected by refrigerant piping 407 to form a refrigerant circuit. The compressor 401 is configured as the compressor 300 shown in Fig. 12. The refrigeration cycle device 400 also includes an outdoor fan 405 facing the condenser 402 and an indoor fan 406 facing the evaporator 404.

[0108] The refrigeration cycle apparatus 400 operates as follows: The compressor 401 compresses the refrigerant it draws in 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 outdoor air sent by the outdoor air 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.

[0109] 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 heat has been removed in the evaporator 404 is supplied by the indoor fan 406 into the room, which is the space to be air-conditioned.

[0110] The compressor 401 of the refrigeration cycle apparatus 400 includes the electric motor 100 of the first embodiment, which has high motor efficiency. Therefore, by using the electric motor 100 as the drive source of the compressor 300 of the refrigeration cycle apparatus 400, the operating efficiency of the refrigeration cycle apparatus 400 can be improved.

[0111] Although the preferred embodiments have been specifically described above, the present disclosure is not limited to the above-described embodiments, and various improvements and modifications can be made.

[0112] DESCRIPTION OF SYMBOLS 1 Stator, 5 Rotor, 10 Stator core, 10A Split core (core segment), 10B Coupled core (core segment), 11 Yoke, 12 Teeth (first teeth, second teeth), 13 Slot, 14 Joint surface, 15 Split surface, 16 Coupler, 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

1. 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 wound around each of the 12×N teeth, and an outer winding wound around the inner winding; having 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; The outer winding wound around the first teeth and the outer winding wound around the second teeth are connected in series. stator.

2. 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. The stator according to claim 1 .

3. 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.