Stator, motor, compressor and refrigeration cycle device

Abstract

The stator core has a ring-shaped core back, N (N is an integer of 2 or more) teeth, and N slots. An outer periphery of the core back has a first straight portion extending in a straight line, a second straight portion extending in a straight line, and a circular arc portion extending in a circular arc between the first straight portion and the second straight portion in a circumferential direction centered on the central axis on a plane perpendicular to the central axis. A radial straight line passing through a center of the circumferential direction of each tooth is set as a tooth center line, and a radial straight line passing through a center of the circumferential direction of each slot is set as a slot center line. A center portion of the circumferential direction of the first straight portion is located on the tooth center line of any tooth of the N teeth. A center portion of the circumferential direction of the second straight portion is located on the slot center line of any slot of the N slots. A recessed portion recessed toward an inner side in the radial direction is formed in at least one of the first straight portion, the second straight portion, and the circular arc portion.

Description

Technical Field

[0001] This disclosure relates to stators, electric motors, compressors, and refrigeration cycle devices. Background Technology

[0002] The compressor includes a compression mechanism, an electric motor that drives the compression mechanism, and a sealed container that houses them. During compression, refrigerant and refrigeration oil that lubricates the compression mechanism circulate within the sealed container. A cutout is provided on the outer periphery of the stator core of the electric motor to serve as a flow path for the refrigeration oil (see, for example, Patent Document 1).

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2006-230054 (for example, see paragraph 0037, Figure 11 ) Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] To improve compressor reliability, it is necessary to enhance the circulation (i.e., oil return) of the refrigerant oil within the sealed container and prevent it from flowing into the refrigerant circuit. Therefore, a larger flow path for the refrigerant oil is preferred. However, increasing the cutout around the stator core narrows the magnetic circuit of the stator core, potentially leading to a decrease in motor performance.

[0008] The purpose of this disclosure is to suppress the degradation of motor performance and improve the oil return and outflow suppression performance of refrigeration oil.

[0009] Methods for solving problems

[0010] The stator disclosed herein has a stator core and a coil wound around the stator core. The stator core has: an annular core back centered on a central axis; N teeth (N being an integer of 2 or more) extending radially inward from the core back towards the central axis; and N slots formed between adjacent teeth in the N teeth. The outer periphery of the core back has a first straight portion extending in a straight line, a second straight portion extending in a straight line, and an arc portion extending in an arc shape in the circumferential direction centered on the central axis between the first and second straight portions. A radial straight line passing through the circumferential center of each of the N teeth is designated as a tooth centerline, and a radial straight line passing through the circumferential center of each of the N slots is designated as a slot centerline. The circumferential center of the first straight portion is located on the tooth centerline of any of the N teeth. The circumferential center of the second straight portion is located on the slot centerline of any of the N slots. At least one of the first straight portion, the second straight portion, and the arc portion has a recessed portion with a radially inward indentation.

[0011] In this disclosure, the stator core is provided with a first straight portion and a second straight portion, and at least one of the first straight portion, the second straight portion, and the arc portion has a recessed portion. Therefore, the flow path area of ​​the refrigeration oil in the compressor, etc., can be ensured without making the magnetic circuit in the stator core too narrow. As a result, the degradation of motor performance can be suppressed, and the oil return and outflow suppression performance of the refrigeration oil can be improved. Attached Figure Description

[0012] Figure 1 This is a cross-sectional view of the electric motor according to Embodiment 1.

[0013] Figure 2 This is a cross-sectional view showing the rotor of Embodiment 1.

[0014] Figure 3 This is a top view showing the stator of Embodiment 1.

[0015] Figure 4 This is a perspective view of the electric motor in Embodiment 1.

[0016] Figure 5 This is a top view showing the stator core of Embodiment 1.

[0017] Figure 6 This is a schematic diagram illustrating the first straight section, the second straight section, and the arc section of the stator core in Embodiment 1.

[0018] Figure 7 This is a first top view used to illustrate the shape of the stator core in Embodiment 1.

[0019] Figure 8 It means in Figure 7Enlarged views (A) and (B) of the portion enclosed by dashed lines 8A and 8B.

[0020] Figure 9 This is a second top view used to illustrate the shape of the stator core in Embodiment 1.

[0021] Figure 10 It means in Figure 9 Enlarged views (A) and (B) of the portion enclosed by dashed lines 10A and 10B.

[0022] Figure 11 This is a third top view used to illustrate the shape of the stator core in Embodiment 1.

[0023] Figure 12 It means in Figure 11 Enlarged views (A) and (B) of the portion enclosed by dashed lines 12A and 12B.

[0024] Figure 13 This is a fourth top view used to illustrate the shape of the stator core in Embodiment 1.

[0025] Figure 14 It means in Figure 13 Enlarged view of the portion enclosed by the dashed line 14.

[0026] Figure 15 It means in Figure 13 Enlarged views (A) and (B) of the portion enclosed by dashed lines 15A and 15B.

[0027] Figure 16 This is a fifth top view used to illustrate the shape of the stator core in Embodiment 1.

[0028] Figure 17 It means in Figure 16 Top view of the section enclosed by the dashed line 17.

[0029] Figure 18 It means in Figure 16 A top view of the section enclosed by the dashed line 18.

[0030] Figure 19 This is a sixth top view used to illustrate the shape of the stator core in Embodiment 1.

[0031] Figure 20 This is a seventh top view used to illustrate the shape of the stator core in Embodiment 1.

[0032] Figure 21 This is a diagram showing the compressor of Embodiment 2.

[0033] Figure 22 This is a diagram showing the refrigeration cycle device of Embodiment 3. Detailed Implementation

[0034] Implementation method 1.

[0035] <Structure of an electric motor>

[0036] Figure 1 This is a top view of the electric motor 3 according to Embodiment 1. The electric motor 3 of Embodiment 1 has an annular stator 1 and a rotatable rotor 5 disposed inside the stator 1. An air gap of 0.25 to 1.0 mm is provided between the stator 1 and the rotor 5.

[0037] Hereinafter, the direction of the central axis Ax, which serves as the center of rotation of rotor 5, will be referred to as the "axial direction". The circumferential direction centered on the central axis Ax will be referred to as the "circumferential direction". The radial direction centered on the central axis Ax will be referred to as the "radial direction".

[0038] <Structure of the rotor>

[0039] Figure 2 This is a cross-sectional view of rotor 5. (e.g.) Figure 2 As shown, the rotor 5 has a rotor core 50 and a permanent magnet 55 mounted on the rotor core 50. The rotor core 50 is formed by stacking electromagnetic steel plates axially and fixing them integrally by riveting or rivets. The thickness of the electromagnetic steel plates is 0.1 to 1.0 mm, and 0.35 mm is an example.

[0040] The rotor core 50 is cylindrical with its central axis Ax as the center. A compressor 8 is fixed in place by pressing through the central hole 50a of the rotor core 50. Figure 21 The axis 90 is the same as the aforementioned central axis Ax.

[0041] The rotor core 50 has a plurality of magnet insertion holes 51 along its outer periphery. Here, six magnet insertion holes 51 are arranged at equal intervals in the circumferential direction. A permanent magnet 55 is disposed in each magnet insertion hole 51.

[0042] One permanent magnet 55 constitutes one magnetic pole. There are six permanent magnets 55, therefore the rotor 5 has six poles. However, the number of poles of the rotor 5 is not limited to six; two or more are acceptable. Alternatively, two or more permanent magnets 55 can be arranged in one magnet insertion hole 51.

[0043] The circumferential center of each magnet insertion hole 51 is the pole center P. A radial straight line passing through the pole center P is designated as the magnetic pole center line. The magnetic pole center line is the d-axis of the rotor 5. The space between adjacent magnet insertion holes 51 is the inter-pole section M.

[0044] The permanent magnet 55 is a flat plate-shaped component having width in the circumferential direction and thickness in the radial direction. The permanent magnet 55 is magnetized in its thickness direction, i.e., radially. The permanent magnet 55 is a neodymium rare-earth magnet containing neodymium (Nd), iron (Fe), and boron (B). However, it can also be a samarium-cobalt magnet or a ferrite magnet containing samarium (Sm) and cobalt (Co). The permanent magnet 55 is a sintered magnet formed by sintering magnetic powder, but it can also be a bonded magnet formed by mixing magnetic powder and resin.

[0045] Magnetic flux barriers 52 are formed at both ends of the magnet insertion hole 51 in the circumferential direction. The magnetic flux barrier 52 is a hole that extends radially from the circumferential end of the magnet insertion hole 51 toward the outer periphery of the rotor core 50. The magnetic flux barrier 52 serves to suppress leakage magnetic flux between adjacent magnetic poles.

[0046] A radially elongated slit 53 is formed on the radially outer side of the magnet insertion hole 51. Here, four slits 53 are formed symmetrically with respect to the magnetic pole centerline. In addition, a circumferentially elongated side slit 54 is formed adjacent to the pole center P side of the magnetic flux barrier 52. However, the number and arrangement of the slits 53 are arbitrary. Furthermore, the rotor core 50 may not necessarily have slits 53 and side slits 54.

[0047] The riveting portion 59, which integrally fixes the electromagnetic steel plate constituting the rotor core 50, is formed on a straight line in the radial direction passing through the inter-pole portion M. Furthermore, the arrangement of the riveting portion 59 is not limited to the arrangement described herein.

[0048] A through hole 56 is formed radially inside the magnet insertion hole 51. Additionally, a through hole 57 is formed radially inside the riveting portion 59, and a through hole 58 is formed radially outside the riveting portion 59. Through holes 56, 57, and 58 all extend axially from one end of the rotor core 50 to the other end.

[0049] Through holes 56, 57, and 58 are used for compressor 8 ( Figure 21 The through holes 56, 57, and 58 are for the flow of refrigerant and refrigeration oil. Any of these holes can also be used as rivet holes. Furthermore, the configuration of the through holes 56, 57, and 58 is not limited to the configuration described herein.

[0050] <Structure of the stator>

[0051] like Figure 1 As shown, the stator 1 has an annular stator core 10 centered on the central axis Ax and a coil 30 wound around the stator core 10. The stator core 10 is formed by stacking multiple electromagnetic steel plates axially and fixing them together integrally by riveting or the like. The thickness of the electromagnetic steel plates is 0.1 to 1.0 mm, and 0.35 mm is an example.

[0052] Figure 3This is a top view showing the stator core 10. The stator core 10 has an annular core back 13 and N teeth 14 extending radially inward from the core back 13. N is an integer greater than or equal to 2. The outer periphery of the core back 13 is connected to the cylindrical outer shell 81. Figure 21 The inner circumferential surface of the casing 81 is fitted together with the compressor 8. Figure 21 It is part of a magnetic material.

[0053] Teeth 14 are formed at equal intervals in the circumferential direction. A wider circumferential tooth tip 14e is formed at the radially inner end of each tooth 14. The tooth tip 14e of tooth 14 is connected to the rotor 5 (…). Figure 2 Opposite. A coil 30 is wound on the tooth 14 in a distributed manner. The number of teeth 14 (N) is 18 here, but any number of 2 or more is acceptable.

[0054] A groove 15 is formed between adjacent teeth 14. The number of grooves 15 is the same as the number of teeth 14 (N), which is 18 in this case. A coil 30 is housed in the groove 15.

[0055] In a plane perpendicular to the central axis Ax, the radial straight line passing through the circumferential center of each tooth 14 is called the tooth centerline T. The tooth centerline T is an imaginary straight line that includes not only the centerline within the tooth 14 but also its extension.

[0056] Similarly, in a plane perpendicular to the central axis Ax, the radial straight line passing through the circumferential center of each groove 15 is called the groove centerline S. The groove centerline S is an imaginary straight line that includes not only the centerline within the groove 15 but also its extension.

[0057] Figure 4 This is a 3D diagram representing motor 3. (For example...) Figure 4 As shown, stator 1 has a first-phase coil 31, a second-phase coil 32, and a third-phase coil 33. For example, the first phase may be the U phase, the second phase the V phase, and the third phase the W phase, but this combination is not limited to. Coils 31, 32, and 33 are referred to as coil 30 when no distinction is needed.

[0058] Coils 31, 32, and 33 each have a conductor made of aluminum or copper and an insulating film covering the conductor. Coil 31 is located on the outermost radial side, and coil 33 is located on the innermost radial side. Coil 32 is located on the outermost radial side of coil 31 and on the innermost radial side of coil 33.

[0059] On the stator core 10, each phase has 3n coils 30 wound around it. n is an integer greater than or equal to 1. More specifically, the stator core 10 has 3n coils 31, 3n coils 32 and 3n coils 33 wound around it.

[0060] exist Figure 4In the example shown, n=1. Therefore, three coils 31, three coils 32, and three coils 33 are wound in the stator core 10. The three coils 31 are connected in series, the three coils 32 are connected in series, and the three coils 33 are connected in series.

[0061] Three coils 31 are arranged at 120-degree intervals in the circumferential direction. Each coil 31 is wound with three slot pitches. Each coil 31 has a coil end 31a extending along the end face of the stator core 10 and a coil side 31b inserted into a slot 15.

[0062] Similarly, the three coils 32 are arranged at 120-degree intervals in the circumferential direction. Each coil 32 is wound with three slot pitches. Each coil 32 has a coil end 32a extending along the end face of the stator core 10 and a coil side 32b inserted into the slot 15.

[0063] Similarly, the three coils 33 are arranged at 120-degree intervals in the circumferential direction. Each coil 33 is wound with three slot pitches. Each coil 33 has a coil end 33a extending along the end face of the stator core 10 and a coil side 33b inserted into the slot 15.

[0064] Coils 31, 32, and 33 are arranged such that the ends of two of them overlap radially. Coil 32 extends from the outer periphery of coil 33 to the inner periphery of coil 31. Due to this arrangement, a coil side is inserted into each of the slots 15 of the stator core 10.

[0065] In the motor 3 of Embodiment 1, as described above, the number of poles is 6, the number of slots is 18, and the slot pitch is 3. Therefore, the winding coefficient kW is 1.

[0066] A centrifuge 60 is mounted at one end of the shaft 90 along its axial direction. The centrifuge 60 has a circular plate portion 61 fixed to the end of the shaft 90 via a fixed shaft 63 and a blade portion 62 fixed to the lower surface of the circular plate portion 61 (see reference). Figure 21 Centrifugal separator 60 is also called an oil separator.

[0067] Centrifuge 60 is positioned radially inside the coil ends 31a, 32a, and 33a of the coils 31, 32, and 33 of the stator 1. Centrifuge 60 passes through the through holes 56, 57, and 58 of the rotor 5. Figure 2 The heavier refrigerant and refrigeration oil in the refrigerant are discharged radially outward.

[0068] The refrigeration oil discharged from the centrifuge 60 flows through the gaps between the stator core 10 and the coil ends 31a, 32a, and 33a to the outer periphery of the stator core 10. The gaps between the stator core 10 and the coil ends 31a, 32a, and 33a are called the stator coil gaps G.

[0069] <Outer periphery shape of stator core 10>

[0070] Figure 5 This is a diagram illustrating the outer periphery shape of the stator core 10. The outer periphery of the back surface 13 of the stator core 10 has a shape formed by cutting away a circle (called the reference circle) C1 centered on the central axis Ax with a first straight section 11A and a second straight section 11B. Both the first straight section 11A and the second straight section 11B are surfaces parallel to the central axis Ax.

[0071] That is, the outer periphery of the back of the iron core 13 has a first straight portion 11A extending in a straight line, a second straight portion 11B extending in a straight line, and an arc portion 12 extending in an arc shape in a plane perpendicular to the central axis Ax. Figure 4 As shown in the perspective view, the first straight section 11A and the second straight section 11B are both planar sections, and the arc section 12 is an arc-shaped section.

[0072] The arc-shaped part 12 and the outer casing 81 of the compressor 8 ( Figure 21 The inner circumferential surfaces of the first straight section 11A and the outer casing 81 are fitted together. A flow path for refrigerant oil is formed between the first straight section 11A and the outer casing 81. In addition, a flow path for refrigerant oil is also formed between the second straight section 11B and the outer casing 81. The first straight section 11A and the second straight section 11B are collectively referred to as straight section 11.

[0073] Figure 6 This is a schematic diagram illustrating the straight sections 11A and 11B and the arc section 12 of the stator core 10. Figure 6 In the text, the first straight section recess 21A, the second straight section recess 21B, and the arc section recess 22, which will be described later, are omitted. Figure 5 ).

[0074] like Figure 6 As shown, the outer periphery of the stator core 10 is composed of two first straight sections 11A, two second straight sections 11B, and four arc sections 12.

[0075] Two first straight sections 11A are formed opposite each other with respect to the central axis Ax. More specifically, the two first straight sections 11A are formed symmetrically with respect to the central axis Ax.

[0076] Each first straight portion 11A is formed on the radially outer side of any tooth 14. More specifically, the circumferential center of each first straight portion 11A is located on the tooth centerline T of any tooth 14.

[0077] Two second straight sections 11B are formed opposite each other with respect to the central axis Ax. More specifically, the two second straight sections 11B are formed symmetrically with respect to the central axis Ax.

[0078] Each second straight section 11B is formed on the radial outer side of the arbitrary groove 15. More specifically, the circumferential center of each second straight section 11B is located on the groove centerline S of the arbitrary groove 15.

[0079] The circumferential center of the second straight section 11B is located at a 90-degree angle relative to the central axis Ax from the circumferential center of the first straight section 11A. Therefore, the outer periphery of the stator core 10 falls within the quadrilateral area. This shape is beneficial for improving the yield rate when punching electromagnetic steel sheets.

[0080] The arc portion 12 is formed circumferentially between the first straight portion 11A and the second straight portion 11B. Here, four arc portions 12 are formed.

[0081] To make the positions of the straight sections 11A and 11B and the arc section 12 more clearly defined, along the outer periphery of the stator core 10 Figure 6 The clockwise direction is defined by points P1 to P8.

[0082] The two ends of the first straight section 11A of one side are points P1 and P2, and the two ends of the first straight section 11A of the other side are points P5 and P6. Similarly, the two ends of the second straight section 11B of one side are points P3 and P4, and the two ends of the second straight section 11B of the other side are points P7 and P8.

[0083] In addition, the two ends of the first arc portion 12 are points P2 and P3, the two ends of the second arc portion 12 are points P4 and P5, the two ends of the third arc portion 12 are points P6 and P7, and the two ends of the fourth arc portion 12 are points P8 and P1.

[0084] Here, we will describe the case where the stator core 10 has two first straight sections 11A, two second straight sections 11B, and four arc sections 12 on its outer periphery, but the number of first straight sections 11A, second straight sections 11B, and arc sections 12 is not limited to these numbers.

[0085] like Figure 5 As shown, a first straight section recess 21A, which is a radially inward recessed portion, is formed at the circumferential center of the first straight section 11A. A second straight section recess 21B, which is a radially inward recessed portion, is formed at the circumferential center of the second straight section 11B.

[0086] An arc-shaped recess 22 is formed in the arc portion 12, which is a portion that is recessed radially inward. The arc-shaped recess 22 is located in the circumferential direction between the first straight portion 11A and the second straight portion 11B.

[0087] The first straight section recess 21A, the second straight section recess 21B, and the arc-shaped section recess 22 are all formed from one end of the stator core 10 along its axial direction to the other end, forming a flow path for the refrigeration oil.

[0088] In embodiment 1, since a first straight portion 11A and a second straight portion 11B are provided on the stator core 10, and further, a first straight portion recess 21A, a second straight portion recess 21B, and an arc-shaped portion recess 22 are provided, the flow path of the refrigeration oil is sufficiently ensured. Therefore, the compressor 8 ( Figure 21 The improved oil return properties of the refrigerant in the refrigeration unit 400 inhibit the flow of refrigeration oil into the refrigeration cycle unit 400. Figure 22 The refrigerant flows out of the refrigerant circuit.

[0089] The first straight-line recess 21A has a triangular shape with a vertex on its inner periphery in a plane perpendicular to the central axis Ax. However, the shape of the first straight-line recess 21A is not limited to a triangular shape; for example, it can also be rectangular or semi-circular. The shape of the second straight-line recess 21B is the same as that of the arc-shaped recess 22.

[0090] The circumferential length L1 of the first straight section 11A and the circumferential length L2 of the second straight section 11B satisfy L1 > L2.

[0091] The first straight section 11A is located radially outside the tooth 14, while the second straight section 11B is located radially outside the slot 15. Therefore, when the distances L1 and L2 are equal (i.e., L1=L2), the magnetic path between the second straight section 11B and the slot 15 becomes narrower, which may lead to magnetic saturation.

[0092] In contrast, when the distances L1 and L2 satisfy L1 > L2, the flow path area between the straight sections 11A and 11B and the outer casing 81 can be ensured, and the magnetic path between the second straight section 11B and the slot 15 will not become too narrow, thus suppressing the generation of magnetic saturation.

[0093] The first straight section recess 21A, the second straight section recess 21B, and the arc section recess 22 of the stator core 10 will be described in detail below.

[0094] Figure 7 This is a first top view used to illustrate the shape of the stator core 10 in Embodiment 1. Figure 7 In the first straight section recess 21A, the point closest to the central axis Ax (i.e., the innermost point on the periphery) is designated as the innermost point V1. The straight line passing through the innermost point V1 and the central axis Ax is designated as the straight line N1.

[0095] Furthermore, the point closest to the central axis Ax (i.e., the innermost point on the periphery) of the concave portion 22 of the arc is designated as the innermost point V2. The straight line passing through the innermost point V2 and the central axis Ax is designated as the straight line N2.

[0096] exist Figure 7 In the diagram, the innermost point V1 of the first straight recess 21A is indicated at a position offset circumferentially from the tooth centerline T. Similarly, the innermost point V2 of the second straight recess 21B is also indicated at a position offset circumferentially from the tooth centerline T.

[0097] Figure 8 (A) is to Figure 7 The diagram shows an enlarged view of the portion enclosed by the dashed line 8A. The distance from the innermost point V1 of the first straight recess 21A to the tooth center line T of the corresponding tooth 14 is defined as H1.

[0098] Furthermore, the distance from the innermost point V1 of the first straight recess 21A to the groove center line S of the nearest groove 15 is defined as H2. Both distances H1 and H2 are along the direction of the reference circle C2 centered on the central axis Ax and passing through the innermost point V1, that is, the circumferential distance.

[0099] The distances H1 and H2 satisfy H1 < H2.

[0100] For reference Figure 4 As explained, a coil 30 is wound on the tooth 14, and the refrigeration oil discharged from the centrifuge 60 goes to the outer periphery of the stator core 10 through the gap between the stator core 10 and the coil ends 31a, 32a, 33a (i.e., the stator coil gap G).

[0101] Since the stator coil gap G is located on tooth 14, the refrigerant oil passing through the stator coil gap G flows most along the tooth centerline T. Therefore, the closer the innermost point V1 of the first straight section recess 21A is to the tooth centerline T, the easier it is for the refrigerant oil passing through the stator coil gap G to flow into the first straight section recess 21A.

[0102] Furthermore, the closer the innermost point V1 of the first straight recess 21A is to the groove 15, the narrower the magnetic path between the first straight recess 21A and the groove 15, and the easier it is for magnetic saturation to occur. Therefore, it is preferable that the innermost point V1 of the first straight recess 21A is as far away from the groove 15 as possible.

[0103] Therefore, in Embodiment 1, the distance H1 from the innermost point V1 of the first straight recess 21A to the tooth center line T and the distance H2 from the innermost point V1 of the first straight recess 21A to the groove center line S of the nearest groove 15 satisfy H1 < H2.

[0104] exist Figure 7 and Figure 8 (A) shows an example where the distance H1 from the innermost point V1 of the first straight recess 21A to the tooth center line T is longer than 0 (i.e., H1 > 0), but the distance H1 can also be 0.

[0105] Figure 8 (B) is to Figure 7 The diagram shows an enlarged view of the portion enclosed by the dashed line 8B. The distance from the innermost point V2 of the arc-shaped recess 22 to the tooth centerline T is defined as H1. The distance from the innermost point V2 of the arc-shaped recess 22 to the groove centerline S of the nearest groove 15 is defined as H2. Distances H1 and H2 satisfy H1 < H2.

[0106] As described above, the refrigeration oil that passes through the stator coil gap G flows the most along the tooth center line T. Therefore, the closer the innermost point V2 of the arc-shaped recess 22 is to the tooth center line T, the easier it is for the refrigeration oil that passes through the stator coil gap G to flow into the arc-shaped recess 22.

[0107] Furthermore, the closer the innermost point V2 of the arc-shaped recess 22 is to the groove 15, the narrower the magnetic path between the arc-shaped recess 22 and the groove 15, and the easier it is for magnetic saturation to occur. Therefore, it is preferable that the innermost point V2 of the arc-shaped recess 22 is as far away from the groove 15 as possible.

[0108] Therefore, in Embodiment 1, the distance H1 from the innermost point V2 of the arc-shaped recess 22 to the tooth center line T and the distance H2 from the innermost point V2 of the arc-shaped recess 22 to the groove center line S of the nearest groove 15 satisfy H1 < H2.

[0109] exist Figure 7 and Figure 8 (B) shows an example where the distance H1 from the innermost point V2 of the arc recess 22 to the tooth center line T is longer than 0 (i.e., H1 > 0), but the distance H1 can also be 0.

[0110] Thus, by making H1 < H2, the reduction in motor performance can be suppressed and the oil return and anti-outflow performance of the refrigeration oil can be improved regarding the first straight section recess 21A and the arc section recess 22.

[0111] Furthermore, an example is shown here where H1 < H2 holds true for both the first straight-line recess 21A and the arc-shaped recess 22, but it is sufficient as long as H1 < H2 holds true for at least one of the first straight-line recess 21A and the arc-shaped recess 22.

[0112] Figure 9 This is a second top view used to illustrate the shape of the stator core 10 in Embodiment 1. Figure 10 (A) represents in Figure 9An enlarged view of the portion enclosed by the dashed line 10A. (See image below.) Figure 10 As shown in (A), the first straight recess 21A is located on the tooth centerline T of the corresponding tooth 14. More preferably, the innermost point V1 of the first straight recess 21A is located on the tooth centerline T.

[0113] Furthermore, the first straight recess 21A is not located on the groove center line S of the groove 15 adjacent to the tooth 14. That is, the points E1 and E2 at both ends of the first straight recess 21A in the circumferential direction are positioned circumferentially inward from the groove center line S of the groove 15 on both sides of the tooth 14. In other words, the groove center line S does not pass between points E1 and E2.

[0114] The refrigerant oil that passes through the stator coil gap G flows most along the tooth centerline T. Therefore, by positioning the innermost point V1 of the first straight section recess 21A on the tooth centerline T, the refrigerant oil can easily flow into the first straight section recess 21A. Furthermore, by ensuring that the first straight section recess 21A is not located on the groove centerline S, the magnetic circuit between the first straight section recess 21A and the groove 15 will not become too narrow, thus suppressing magnetic saturation.

[0115] Figure 10 (B) indicates that in Figure 9 An enlarged view of the portion enclosed by the dashed line 10B. (See image below.) Figure 10 As shown in (B), the arc-shaped recess 22 is located on the tooth centerline T of the corresponding tooth 14. More preferably, the innermost point V2 of the arc-shaped recess 22 is located on the tooth centerline T.

[0116] Furthermore, the arc-shaped recess 22 is not located on the groove center line S of the groove 15 adjacent to the tooth 14. That is, the points F1 and F2 at both ends of the arc-shaped recess 22 are positioned circumferentially inward from the groove center line S of the groove 15 on both sides of the tooth 14. In other words, the groove center line S does not pass between points F1 and F2.

[0117] The refrigerant oil flowing through the stator coil gap G flows most along the tooth centerline T. Therefore, by positioning the innermost point V2 of the arc-shaped recess 22 on the tooth centerline T, the refrigerant oil can easily flow into the arc-shaped recess 22. Furthermore, by ensuring that the arc-shaped recess 22 is not located on the groove centerline S, the magnetic circuit between the arc-shaped recess 22 and the groove 15 will not become too narrow, thus suppressing magnetic saturation.

[0118] In this way, both the first straight section recess 21A and the arc section recess 22 are located on the tooth centerline T and not on the groove centerline S, thereby suppressing the deterioration of the motor performance and improving the oil return and anti-outflow performance of the refrigeration oil.

[0119] Furthermore, here we have described an example in which both the first straight-line recess 21A and the arc recess 22 are located on the tooth centerline T but not on the groove centerline S. However, it is also possible for at least one of the first straight-line recess 21A and the arc recess 22 to be located on the tooth centerline T but not on the groove centerline S.

[0120] Figure 11 This is a third top view used to illustrate the shape of the stator core 10 in Embodiment 1. Figure 12 (A) represents in Figure 11 An enlarged view of the portion enclosed by the dashed line 12A. (See image below.) Figure 12 As shown in (A), the depth Dt of the first straight recess 21A on the tooth centerline T is deeper than the depth Ds on the groove centerline S. That is, Dt > Ds holds true.

[0121] The depths Dt and Ds of the first straight section recess 21A are both distances from the inner edge of the first straight section recess 21A to the imaginary straight line C3 of the specified straight section 11A. The reference straight line C3 is also a straight line connecting the points E1 and E2 at both circumferential ends of the specified first straight section recess 21A.

[0122] The refrigerant oil that passes through the stator coil gap G flows most along the tooth centerline T. Therefore, by making the depth Dt of the first straight section recess 21A on the tooth centerline T deeper, the refrigerant oil can easily flow into the first straight section recess 21A. In addition, by making the depth Ds of the first straight section recess 21A on the groove centerline S shallower, the magnetic circuit between the first straight section recess 21A and the groove 15 will not become too narrow, and the occurrence of magnetic saturation can be suppressed.

[0123] like Figure 12 As shown in (B), the depth Dt of the arc-shaped recess 22 on the tooth centerline T is deeper than the depth Ds on the groove centerline S. That is, Dt > Ds holds true. The depths Dt and Ds of the arc-shaped recess 22 are both distances from the inner edge of the arc-shaped recess 22 to the reference circle C1.

[0124] The refrigerant oil flowing through the stator coil gap G flows most along the tooth centerline T. Therefore, by making the depth Dt of the arc-shaped recess 22 on the tooth centerline T deeper, the refrigerant oil can easily flow into the arc-shaped recess 22. In addition, by making the depth Ds of the arc-shaped recess 22 on the groove centerline S shallower, the magnetic circuit between the arc-shaped recess 22 and the groove 15 will not become too narrow, thus suppressing the occurrence of magnetic saturation.

[0125] Thus, by making Dt > Ds true for the first straight-line recess 21A and the arc recess 22, it is possible to suppress the deterioration of the motor performance and improve the oil return and anti-outflow performance of the refrigeration oil.

[0126] Furthermore, an example is shown here where Dt > Ds holds for both the first straight-line recess 21A and the arc-shaped recess 22, but it is sufficient as long as Dt > Ds holds for at least one of the first straight-line recess 21A and the arc-shaped recess 22.

[0127] Figure 13 This is a fourth top view used to illustrate the shape of the stator core 10 in Embodiment 1. (As shown) Figure 13 As shown, a first arc-shaped recess 22A and a second arc-shaped recess 22B are formed in the arc portion 12. The first arc-shaped recess 22A is located on the tooth center line T of the corresponding tooth 14. The second arc-shaped recess 22B is located on the groove center line S of the corresponding groove 15.

[0128] Here, the first arc-shaped recess 22A is located on the side of the first straight section 11A, and the second arc-shaped recess 22B is located on the side of the second straight section 11B, but the arrangement of the arc-shaped recesses 22A and 22B can also be reversed.

[0129] Figure 14 It means in Figure 13 An enlarged view of the portion enclosed by the dashed line 14. (See image below.) Figure 14 As shown, in a plane perpendicular to the central axis Ax, the first arc-shaped recess 22A has an area S1, and the second arc-shaped recess 22B has an area S2.

[0130] Area S1 is the area of ​​the region enclosed by the inner edge of the first arc-shaped recess 22A and the reference circle C1. Area S2 is the area of ​​the region enclosed by the inner edge of the second arc-shaped recess 22B and the reference circle C1.

[0131] The areas S1 and S2 of the first arc-shaped recessed portion 22A and the second arc-shaped recessed portion 22B satisfy S1 > S2.

[0132] As described above, the refrigerant oil passing through the stator coil gap G flows radially outward on the tooth 14. Therefore, by making the area S1 of the first arc-shaped recess 22A larger, the refrigerant oil can easily flow into the first arc-shaped recess 22A. In addition, by making the area S2 of the second arc-shaped recess 22B smaller, the magnetic circuit between the second arc-shaped recess 22B and the groove 15 will not become too narrow, and the generation of magnetic saturation can be suppressed.

[0133] In addition, Figure 14 In the example shown, the circumferential length W1 of the first arc-shaped recess 22A is longer than the circumferential length W2 of the second arc-shaped recess 22B, and the radial depth D1 of the first arc-shaped recess 22A is deeper than the radial depth D2 of the second arc-shaped recess 22B. However, this example is not limited to this one; it is acceptable as long as S1 > S2 as stated above.

[0134] In this way, by making the areas S1 and S2 of the first arc recessed portion 22A and the second arc recessed portion 22B satisfy S1 > S2, it is possible to suppress the deterioration of the motor performance and improve the oil return and anti-outflow performance of the refrigeration oil.

[0135] Figure 15 (A) represents in Figure 13 An enlarged view of the portion enclosed by the dashed line 15A. (See image below.) Figure 15 As shown in (A), the first straight recess 21A is located on the tooth center line T of the corresponding tooth 14.

[0136] Furthermore, the first straight section recess 21A has an area S3 in a plane perpendicular to the central axis Ax. The area S3 is the area of ​​the region enclosed by the inner edge of the first straight section recess 21A and the reference straight line C3 defining the first straight section 11A.

[0137] Figure 15 (B) indicates that in Figure 13 An enlarged view of the portion enclosed by the dashed line 15B. (See image below.) Figure 15 As shown in (B), the second straight recess 21B is located on the groove center line S of the corresponding groove 15.

[0138] Furthermore, the second straight section recess 21B has an area S4 in a plane perpendicular to the central axis Ax. The area S4 is the area of ​​the region enclosed by the inner edge of the second straight section recess 21B and the reference straight line C4 defining the second straight section 11B.

[0139] like Figure 15 As shown in (A) and (B), the areas S3 and S4 of the straight and recessed portions 21A and 21B satisfy S3 > S4.

[0140] As described above, the refrigerant oil passing through the stator coil gap G flows radially outward on the tooth 14. Therefore, by making the area S3 of the first straight section recess 21A larger, the refrigerant oil can easily flow into the first straight section recess 21A. In addition, by making the area S4 of the second straight section recess 21B smaller, the magnetic circuit between the second straight section recess 21B and the groove 15 will not become too narrow, and the generation of magnetic saturation can be suppressed.

[0141] In addition, Figure 15 In the examples shown in (A) and (B), the circumferential length W3 of the first straight recess 21A is longer than the circumferential length W4 of the second straight recess 21B, and the radial depth D3 of the first straight recess 21A is deeper than the radial depth D4 of the second straight recess 21B. However, this example is not limited to this one; it is acceptable as long as S3 > S4 is true.

[0142] In this way, by making the areas S3 and S4 of the first straight recess 21A and the second straight recess 21B satisfy S3 > S4, it is possible to suppress the deterioration of the motor performance and improve the oil return and anti-outflow performance of the refrigeration oil.

[0143] Figure 16 This is a fifth top view used to illustrate the shape of the stator core 10 in Embodiment 1. (As shown...) Figure 16 As shown, a first arc-shaped recess 22A and a second arc-shaped recess 22B are formed in the arc portion 12. The first arc-shaped recess 22A is located on the tooth center line T of the corresponding tooth 14, and the second arc-shaped recess 22B is located on the groove center line S of the corresponding groove 15.

[0144] Figure 17 It means in Figure 16 An enlarged view of the portion enclosed by the dashed line 17. (See image below.) Figure 17 As shown, the first arc-shaped recess 22A has an area S1, and the first straight recess 21A has an area S3. The area S1 is as shown in the reference... Figure 14 As explained. Area S3 is as shown in the reference. Figure 15 As explained in (A).

[0145] The areas S1 and S3 of the first arc-shaped recessed portion 22A and the first straight-line recessed portion 21A satisfy S1 > S3.

[0146] Both the first straight section recess 21A and the first arc section recess 22A are located on the tooth centerline T, but the first straight section 11A is closer to the central axis Ax than the arc section 12. Therefore, when the areas S1 and S3 are equal (i.e., S1=S3), the magnetic circuit between the first straight section recess 21A and the groove 15 becomes narrower, which may lead to magnetic saturation.

[0147] By making the area S3 of the first straight-line recess 21A smaller than the area S1 of the first arc recess 22A (i.e., S1 > S3), the magnetic circuit between the first straight-line recess 21A and the groove 15 will not become too narrow, thus suppressing the generation of magnetic saturation.

[0148] In addition, Figure 17 In the example shown, the circumferential length W1 of the first arc-shaped recess 22A is longer than the circumferential length W3 of the first straight recess 21A, and the radial depth D1 of the first arc-shaped recess 22A is deeper than the radial depth D3 of the first straight recess 21A. However, this example is not limited to this one; it is acceptable as long as S1 > S3 is true.

[0149] In this way, by making the areas S1 and S3 of the first arc-shaped recessed portion 22A and the first straight-line recessed portion 21A satisfy S1 > S3, the generation of magnetic saturation can be suppressed, and the reduction of motor performance can be suppressed.

[0150] Figure 18 It means in Figure 16 An enlarged view of the portion enclosed by the dashed line 18. (See image below.) Figure 18 As shown, the second arc-shaped recess 22B has an area S2, and the second straight recess 21B has an area S4. The area S2 is as shown in the reference... Figure 14 As explained. Area S4 is as shown in the reference. Figure 15 As explained in (B), the areas S2 and S4 satisfy S2 > S4.

[0151] Both the second straight section recess 21B and the second arc section recess 22B are located on the center line S of the groove, but the second straight section 11B is closer to the central axis Ax than the arc section 12. Therefore, when the areas S2 and S4 are equal (i.e., S2=S4), the magnetic circuit between the second straight section recess 21B and the groove 15 becomes narrower, which may lead to magnetic saturation.

[0152] By making the area S4 of the second straight recess 21B smaller than the area S2 of the second arc recess 22B (i.e., S2 > S4), the magnetic circuit between the second straight recess 21B and the groove 15 will not become too narrow, thus suppressing the generation of magnetic saturation.

[0153] Furthermore, here, the circumferential length W2 of the second arc-shaped recess 22B is longer than the circumferential length W4 of the second straight recess 21B, and the radial depth D2 of the second arc-shaped recess 22B is deeper than the radial depth D4 of the second straight recess 21B. However, this example is not limited to this one; it is acceptable as long as S2 > S4 as stated above.

[0154] In this way, by making the areas S2 and S4 of the second arc-shaped recessed portion 22B and the second straight-line recessed portion 21B satisfy S2 > S4, it is possible to suppress the generation of magnetic saturation and suppress the reduction of motor performance.

[0155] Figure 19 This is a sixth top view used to illustrate the shape of the stator core 10 in Embodiment 1. (As shown...) Figure 19 As shown, a first arc-shaped recess 22C and a second arc-shaped recess 22D are formed in the arc portion 12.

[0156] The first arc-shaped recess 22C is located on the tooth center line T of the corresponding tooth 14, and the second arc-shaped recess 22D is located on the tooth center line T of the corresponding tooth 14. In addition, the first arc-shaped recess 22C is located on the side of the first straight section 11A, and the second arc-shaped recess 22D is located on the side of the second straight section 11B.

[0157] In a plane perpendicular to the central axis Ax, the first arc-shaped recess 22C has an area S5, and the second arc-shaped recess 22D has an area S6. Area S5 is the area of ​​the region enclosed by the inner edge of the first arc-shaped recess 22C and the reference circle C1. Area S6 is the area of ​​the region enclosed by the inner edge of the second arc-shaped recess 22D and the reference circle C1.

[0158] The areas S5 and S6 of the first arc-shaped recessed portion 22C and the second arc-shaped recessed portion 22D satisfy S5 < S6.

[0159] The second straight section 11B and the outer casing 81 ( Figure 21 The area of ​​the flow path formed between the second straight portion 11A and the outer casing 81 is smaller than the area of ​​the flow path formed between the first straight portion 11A and the outer casing 81. Therefore, by making the area S6 of the second arc-shaped recess 22D adjacent to the second straight portion 11B larger than the area S5 of the first arc-shaped recess 22C, the flow rate of the refrigeration oil can be increased.

[0160] In this way, by making the areas S5 and S6 of the first arc-shaped recessed portion 22C and the second arc-shaped recessed portion 22D satisfy S5 < S6, the oil return property and the performance of preventing leakage of the refrigeration oil can be improved.

[0161] Figure 20 This is the seventh top view used to illustrate the shape of the stator core 10 in Embodiment 1. (As shown...) Figure 20 As shown, an arc-shaped recess 22 is formed in the arc portion 12. The arc-shaped recess 22 is formed on the tooth centerline T of the corresponding tooth 14.

[0162] The distance from the arc-shaped recess 22 to the first straight section 11A is defined as B1, and the distance from the arc-shaped recess 22 to the second straight section 11B is defined as B2. Distance B1 is the distance from the end point F1 of the arc-shaped recess 22 on the first straight section 11A side to point P2, which serves as the boundary between the first straight section 11A and the arc-shaped section 12. Distance B2 is the distance from the end point F2 of the arc-shaped recess 22 on the second straight section 11B side to point P3, which serves as the boundary between the second straight section 11B and the arc-shaped section 12.

[0163] The distance B1 from the arc-shaped recess 22 to the first straight section 11A and the distance B2 from the arc-shaped recess 22 to the second straight section 11B satisfy B1 > B2. In other words, the arc-shaped recess 22 is formed at a position closer to the second straight section 11B than the circumferential center of the arc-shaped section 12.

[0164] As described above, in the second straight section 11B and the outer casing 81 ( Figure 21The area of ​​the flow path formed between the first straight portion 11A and the outer casing 81 is smaller than the area of ​​the flow path formed between the first straight portion 11A and the outer casing 81. Therefore, by making the arc-shaped recessed portion 22 closer to the second straight portion 11B than the first straight portion 11A, the flow rate of the refrigeration oil can be increased.

[0165] In this way, by ensuring that the distance B1 from the arc-shaped recess 22 to the first straight section 11A and the distance B2 from the arc-shaped recess 22 to the second straight section 11B satisfy B1 > B2, the oil return properties and outflow prevention performance of the refrigeration oil can be improved.

[0166] Here, the case where the number of slots in the stator core 10 is 18 is explained, but the number of slots is not limited to 18; for example, it can also be 24, 36, etc.

[0167] Furthermore, an example in which a first straight section recess 21A is formed on both of the two first straight sections 11A has been described, but it is sufficient that a first straight section recess 21A is formed on at least one first straight section 11A.

[0168] Similarly, an example in which a second straight section recess 21B is formed on both sides of the two second straight sections 11B has been described, but it is sufficient that a second straight section recess 21B is formed on at least one second straight section 11B.

[0169] Similarly, an example in which all four arcuate portions 12 have arcuate recesses 22 is described here, but it is sufficient that at least one arcuate recess 22 is formed in the arcuate portion 12.

[0170] In addition, an example in which a first straight section recess 21A is formed in the first straight section 11A, a second straight section recess 21B is formed in the second straight section 11B, and an arc section recess 22 is formed in the arc section 12 has been described. However, it is sufficient that at least one of the first straight section 11A, the second straight section 11B, and the arc section 12 is formed with a recess.

[0171] <Effects of the Implementation Method>

[0172] As described above, in the stator 1 of Embodiment 1, the stator core 10 has an annular core back 13, N teeth (N being an integer of 2 or more) 14, and N slots 15. The outer periphery of the core back 13 has a first straight portion 11A extending in a straight line, a second straight portion 11B extending in a straight line, and an arc portion 12 extending in an arc shape between the first straight portion 11A and the second straight portion 11B in the circumferential direction in a plane perpendicular to the central axis Ax. The circumferential center of the first straight portion 11A is located on the tooth centerline T of any tooth 14. The circumferential center of the second straight portion 11B is located on the slot centerline S of any slot 15. At least one of the first straight portion 11A, the second straight portion 11B, and the arc portion 12 has a radially inwardly recessed portion (i.e., at least one of the first straight portion recess 21A, the second straight portion recess 21B, and the arc portion recess 22).

[0173] In this way, the stator core 10 is provided with a first straight section 11A and a second straight section 11B, and at least one of the first straight section 11A, the second straight section 11B, and the arc section 12 is provided with a recess. Therefore, the flow path of the refrigeration oil can be adequately ensured without making the magnetic circuit within the stator core 10 too narrow. That is, it is possible to avoid the degradation of motor performance and improve the oil return and outflow suppression performance of the refrigeration oil.

[0174] In addition, the coil 30 is wound in a distributed manner with 3n coils (n is an integer greater than or equal to 1) of each phase of the stator core 10, and the winding factor is 1. Therefore, the magnetic flux of the permanent magnet 55 can be linked with the coil 30 most efficiently, thereby improving the performance of the motor.

[0175] Furthermore, since the stator core 10 has 18 slots 15 (i.e., N=18), it is possible to realize an electric motor 3 with a first straight section 11A, a second straight section 11B, and an arc section 12 as described above, and with a winding coefficient of 1.

[0176] Implementation method 2.

[0177] Next, the compressor 8 of Embodiment 2 will be described. Figure 21 This is a cross-sectional view of compressor 8. Compressor 8 here is a rotary compressor.

[0178] The compressor 8 includes a sealed container 80, a compression mechanism 9 disposed within the sealed container 80, an electric motor 3 that drives the compression mechanism 9, a shaft 90 connecting the electric motor 3 and the compression mechanism 9, and a centrifugal separator 60 fixed to the shaft 90. The structure of the electric motor 3 is as described in Embodiment 1.

[0179] Centrifuge 60 is positioned above the rotor 5 of motor 3 and radially inside the coil 30 of stator 1. Centrifuge 60 has a circular plate portion 61 fixed to the upper end of shaft 90 via a fixed shaft 63 and a blade portion 62 fixed to the lower surface of the circular plate portion 61.

[0180] The sealed container 80 is, for example, a sealed container formed of steel plate, covering the electric motor 3 and the compression mechanism 9. The sealed container 80 has a shell 81 and a container upper part 82. The container upper part 82 is equipped with: a glass terminal 83 as a terminal portion for supplying power from the outside of the compressor 8 to the electric motor 3; and a discharge pipe 85 for discharging the refrigerant compressed within the compressor 8 to the outside. The electric motor 3 and the compression mechanism 9 are housed within the shell 81.

[0181] The compression mechanism 9 has an annular first cylinder 91 and a second cylinder 92 along the shaft 90. The first cylinder 91 and the second cylinder 92 are fixed to the inner circumference of the housing 81. An annular first piston 93 is disposed on the inner circumference side of the first cylinder 91, and an annular second piston 94 is disposed on the inner circumference side of the second cylinder 92. The first piston 93 and the second piston 94 are rotary pistons that rotate together with the shaft 90.

[0182] A partition plate 97 is provided between the first cylinder 91 and the second cylinder 92. The partition plate 97 is a circular plate-shaped component with a through hole in the center. Blades (not shown) are provided in the cylinder chambers of the first cylinder 91 and the second cylinder 92 to divide the cylinder chambers into an intake side and a compression side. The first cylinder 91, the second cylinder 92 and the partition plate 97 are fixed together by bolts 98.

[0183] An upper frame 95 is disposed above the first cylinder 91 to block the upper side of the cylinder chamber of the first cylinder 91. A lower frame 96 is disposed below the second cylinder 92 to block the lower side of the cylinder chamber of the second cylinder 92. The upper frame 95 and the lower frame 96 support the shaft 90 so that it can rotate.

[0184] At the bottom of the outer casing 81, there is an oil reservoir 86 for storing refrigerant oil that lubricates the sliding parts of the compression mechanism 9. The refrigerant oil rises within a hole 90a formed axially inside the shaft 90, and exits from multiple oil supply holes 90b formed at various locations on the shaft 90. Figure 21 (Only one location is shown in the image) The sliding part supplied to the compression mechanism 9.

[0185] The stator 1 of the electric motor 3 is mounted inside the housing 81 via thermoforming. Power is supplied to the coil 30 of the stator 1 from the glass terminal 83 mounted on the upper part 82 of the container via lead wire 84. As described above, the rotor 5 is fixed to the shaft 90.

[0186] A receiver 87 for storing refrigerant gas is installed on the housing 81. The receiver 87 is installed, for example, on the outside of the housing 81. A pair of suction pipes 88, 89 are installed on the housing 81, through which refrigerant gas is supplied from the receiver 87 to cylinders 91, 92.

[0187] As a refrigerant, refrigerants such as R410A, R407C, or R22 can be used, but from the perspective of preventing global warming, refrigerants with low GWP (Global Warming Potential) are preferred. Examples of refrigerants with low GWP include the following.

[0188] (1) First, haloalkanes with carbon-carbon double bonds in their composition can be used, such as HFO (Hydro-Fluoro-Orefin)-1234yf (CF3CF=CH2). The GWP of HFO-1234yf is 4.

[0189] (2) Alternatively, hydrocarbons with carbon-carbon double bonds in their composition can be used, such as R1270 (propylene). R1270 has a GWP of 3, which is lower than HFO-1234yf, but its flammability is higher than that of HFO-1234yf.

[0190] (3) Alternatively, a mixture containing at least one of a halogenated hydrocarbon having a carbon-carbon double bond in its composition and a hydrocarbon having a carbon-carbon double bond in its composition may be used, such as a mixture of HFO-1234yf and R32. HFO-1234yf is a low-pressure refrigerant, and therefore tends to have a large pressure drop, which may lead to a decrease in the performance of the refrigeration cycle (especially the evaporator). Therefore, in practice, it is preferable to use a mixture with R32 or R41, which are refrigerants with a higher pressure than HFO-1234yf.

[0191] The basic operation of compressor 8 is as follows. Refrigerant gas supplied from receiver 87 is supplied to the respective cylinder chambers of first cylinder 91 and second cylinder 92 through suction pipes 88 and 89. When motor 3 is driven and rotor 5 rotates, shaft 90 rotates together with rotor 5.

[0192] When shaft 90 rotates, the first piston 93 and the second piston 94, which are engaged with shaft 90, rotate eccentrically in the respective cylinder chambers of cylinders 91 and 92, compressing the refrigerant. The compressed refrigerant is discharged from cylinders 91 and 92, passing through the through holes 56, 57, and 58 of rotor 5. Figure 2 And so on.

[0193] On the other hand, the refrigeration oil stored in the oil reservoir 86 at the bottom of the compressor 8 rises within the hole 90a formed in the shaft 90 and is supplied to each sliding part of the compression mechanism 9 through the oil supply hole 90b. Additionally, a portion of the refrigeration oil, along with the refrigerant, passes through the through holes 56, 57, and 58 of the rotor 5. Figure 2And rise.

[0194] The refrigerant and refrigeration oil passing through the through holes 56, 57, and 58 of rotor 5 collide with centrifugal separator 60. Since the refrigeration oil is heavier than the refrigerant, it is discharged radially outward by centrifugal separator 60.

[0195] Therefore, the refrigerant rises further within the casing 81 and is discharged from the discharge pipe 85, being sent to the refrigeration cycle unit 400. Figure 22 ( ) refrigerant circuit.

[0196] On the other hand, the refrigeration oil discharged from the centrifuge 60 flows radially outward through the gap between the stator core 10 and the coil 30, collides with the inner surface of the outer casing 81, and flows into the flow path between the straight portions 11A and 11B (including the straight portion recesses 21A and 21B) of the stator core 10 and the outer casing 81, as well as the flow path between the arc-shaped recess 22 and the outer casing 81. The refrigeration oil flows downward in the flow path and returns to the oil storage section 86.

[0197] The refrigeration oil circulates smoothly within the compressor 8, preventing it from being discharged from the discharge pipe 85 along with the refrigerant. Therefore, it prevents refrigeration oil from mixing into the refrigerant circuit of the refrigeration cycle unit and also prevents insufficient refrigeration oil for lubricating the compressor mechanism 9.

[0198] The compressor 8 in Embodiment 2 has the electric motor 3 described in Embodiment 1, which improves the oil return properties and outflow suppression performance of the refrigeration oil. Therefore, it prevents refrigeration oil from mixing into the refrigerant circuit of the refrigeration cycle unit and prevents insufficient refrigeration oil for lubricating the compressor mechanism 9.

[0199] Furthermore, since the centrifugal separator 60 is located radially inside the coil ends 31a, 32a, and 33a of the coil 30 of the stator 1, the refrigeration oil discharged from the centrifugal separator 60 can pass through the gap between the stator core 10 and the coil ends 31a, 32a, and 33a to the straight portions 11A and 11B (including the straight portion recesses 21A and 21B) and the arc-shaped portion recess 22. This further improves the oil return properties and outflow suppression performance of the refrigeration oil.

[0200] Implementation method 3.

[0201] Next, the refrigeration cycle device 400 of Embodiment 3 will be described. Figure 22 This is a diagram representing a refrigeration cycle device 400. The refrigeration cycle device 400 is, for example, an air conditioning unit, but is not limited to this; it could also be, for example, a refrigerator.

[0202] Figure 22The refrigeration cycle unit 400 shown includes a compressor 401, a condenser 402 for condensing refrigerant, a pressure reducing device 403 for reducing refrigerant pressure, and an evaporator 404 for evaporating refrigerant. The compressor 401, condenser 402, and pressure reducing device 403 are located in the outdoor unit 410, and the evaporator 404 is located in the indoor unit 420.

[0203] Compressor 401, condenser 402, pressure reducing device 403, and evaporator 404 are connected via refrigerant piping 407 to form a refrigerant circuit. Compressor 401 is the compressor 8 described in Embodiment 2. Figure 21 The refrigeration cycle unit 400 is composed of an outdoor fan 405 opposite to the condenser 402 and an indoor fan 406 opposite to the evaporator 404.

[0204] The refrigeration cycle unit 400 operates as follows: The compressor 401 compresses the intake refrigerant and delivers it as a high-temperature, high-pressure refrigerant gas. The condenser 402 performs heat exchange between the refrigerant from the compressor 401 and the outdoor air supplied by the outdoor fan 405, condensing the refrigerant and delivering it as a liquid refrigerant. The pressure reducing device 403 expands the liquid refrigerant from the condenser 402, delivering it as a low-temperature, low-pressure liquid refrigerant.

[0205] The evaporator 404 performs heat exchange between the low-temperature, low-pressure liquid refrigerant supplied from the pressure reducing device 403 and the indoor air, causing the refrigerant to evaporate and be released as refrigerant gas. The heated air obtained by the evaporator 404 is supplied to the room through the indoor fan 406.

[0206] In the refrigeration cycle device 400 of Embodiment 3, the compressor 401 is composed of the compressor 8 described in Embodiment 2, thus preventing the mixing of refrigeration oil into the refrigerant circuit. Therefore, it is possible to prevent the reduction in operating efficiency caused by the mixing of refrigeration oil, and to improve the operating efficiency of the refrigeration cycle device 400.

[0207] The preferred embodiments have been described in detail above, but this disclosure is not limited to the above embodiments and various improvements or modifications can be made.

[0208] Label Explanation

[0209] 1: Stator; 5: Rotor; 8: Compressor; 9: Compression mechanism; 10: Stator core; 11A: First straight section; 11B: Second straight section; 12: Arc section; 13: Back of core; 14: Tooth; 15: Slot; 21A: Recessed portion of the first straight section; 21B: Recessed portion of the second straight section; 22: Recessed portion of the arc section; 22A, 22C: Recessed portion of the first arc section; 22B, 22D: Recessed portion of the second arc section. 30, 31, 32, 33: Coils; 31a, 32a, 33a: Coil ends; 50: Rotor core; 51: Magnet insertion hole; 55: Permanent magnet; 56, 57, 58: Through holes; 60: Centrifuge; 80: Sealed container; 81: Outer shell; 86: Oil reservoir; 90: Shaft; 400: Refrigeration cycle device; 401: Compressor; 402: Condenser; 403: Pressure reducing device; 404: Evaporator; G: Stator coil gap; S: Slot centerline; T: Tooth centerline.

Claims

1. A stator having: Stator core; and A coil, which is wound around the stator core, The stator core has: The back of the annular iron core centered on the central axis; N teeth, which extend radially inward from the back of the iron core towards the central axis, wherein, N is an integer greater than 2; and N slots are formed between two adjacent teeth in the N teeth. The outer periphery of the back of the iron core has a first straight portion extending in a straight line, a second straight portion extending in a straight line, and an arc portion extending in an arc shape between the first straight portion and the second straight portion in the circumferential direction centered on the central axis. The radial straight line passing through the circumferential center of each of the N teeth is defined as the tooth centerline. The radial straight line passing through the circumferential center of each of the N slots is defined as the slot centerline. The circumferential center of the first straight section is located on the tooth centerline of any one of the N teeth. The circumferential center of the second straight section is located on the center line of any of the N slots. At least one of the first straight portion, the second straight portion, and the arc portion is formed with a recessed portion that is recessed inward toward the radial direction.

2. The stator according to claim 1, wherein, The coils are wound on the stator core in a distributed winding manner, with 3n coils per phase, where n is an integer greater than or equal to 1, and the winding coefficient is 1.

3. The stator according to claim 1 or 2, wherein, N is 18.

4. The stator according to any one of claims 1 to 3, wherein, The circumferential length L1 of the first straight section and the circumferential length L2 of the second straight section satisfy L1 > L2.

5. The stator according to any one of claims 1 to 4, wherein, The recessed portion is located on the center line of any one of the N teeth. The point closest to the central axis in the recess is designated as the innermost point. Let H1 be the distance from the innermost point of the recess to the center line of the tooth. Let H2 be the distance from the innermost point of the recess to the center line of the groove closest to the innermost point among the N grooves. At this point, H1 < H2 holds true.

6. The stator according to any one of claims 1 to 5, wherein, The recess is located on the center line of any of the N teeth, but not on the center line of the groove adjacent to that tooth in the circumferential direction.

7. The stator according to any one of claims 1 to 6, wherein, The recessed portion is located on the center line of any one of the N teeth. The recessed portion has a depth Dt on the center line of the tooth and a depth Ds on the center line of the groove. The statement Dt > Ds holds true.

8. The stator according to any one of claims 1 to 7, wherein, In the arc portion, a first arc portion recessed portion is formed as the recessed portion, located on the center line of any tooth among the N teeth, and a second arc portion recessed portion is formed on the center line of any groove among the N grooves. In a plane perpendicular to the central axis, the area S1 of the first arc-shaped recess and the area S2 of the second arc-shaped recess satisfy S1 > S2.

9. The stator according to any one of claims 1 to 8, wherein, A first straight section recess is formed in the first straight section, which is located on the tooth centerline of any of the N teeth and serves as the recessed portion. A second straight section recess is formed in the second straight section, which is located on the center line of any of the N grooves. In a plane perpendicular to the central axis, the area S3 of the first straight recess and the area S4 of the second straight recess satisfy S3 > S4.

10. The stator according to any one of claims 1 to 9, wherein, A first straight section recess is formed in the first straight section, which is located on the tooth centerline of any of the N teeth and serves as the recessed portion. An arc-shaped recess is formed in the arc portion, located on the center line of any one of the N teeth. In a plane perpendicular to the central axis, the area S1 of the arc-shaped recess and the area S3 of the first straight-line recess satisfy S1 > S3.

11. The stator according to any one of claims 1 to 10, wherein, The arc-shaped recessed portion, which is formed on the center line of any of the N grooves, is a recessed portion. A second straight section recess is formed in the second straight section, which is located on the center line of any of the N grooves. In a plane perpendicular to the central axis, the area S2 of the arc-shaped recess and the area S4 of the second straight-line recess satisfy S2 > S4.

12. The stator according to any one of claims 1 to 11, wherein, The arc portion has a first arc portion recess and a second arc portion recess, which serve as the recessed portion. The first arc-shaped recessed portion and the second arc-shaped recessed portion are arranged from the first straight portion toward the second straight portion in the order of the first arc-shaped recessed portion and the second arc-shaped recessed portion. In a plane perpendicular to the central axis, the area S5 of the first arc-shaped recess and the area S6 of the second arc-shaped recess satisfy S5 < S6.

13. The stator according to any one of claims 1 to 12, wherein, The distance B1 from the recessed portion of the arc portion to the first straight portion and the distance B2 from the recessed portion of the arc portion to the second straight portion satisfy B1 > B2.

14. An electric motor, comprising: The stator according to any one of claims 1 to 13; and The rotor is located inside the stator.

15. A compressor comprising: The electric motor according to claim 14; A compression mechanism, which is driven by the electric motor; A shaft connecting the electric motor and the compression mechanism; and A centrifuge, which is fixed to the shaft.

16. The compressor according to claim 15, wherein, The centrifuge is located radially inside the coil end of the stator's coil.

17. A refrigeration cycle apparatus comprising a compressor, a condenser, a pressure reducing device, and an evaporator as described in claim 15 or 16.

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