Rotor, motor, compressor, and refrigeration cycle device

Abstract

This rotor has: an annular rotor core that extends in a circumferential direction around a rotation axis and has a magnet insertion hole; and a permanent magnet disposed in the magnet insertion hole. The rotor core has m (where m is an integer of 1 or more) first voids and n (where n is an integer of 1 or more) second voids in a region between the inner circumference of the rotor core and the magnet insertion hole in a radial direction centered on the rotation axis. When one side is defined as a first side and the other side is defined as a second side with respect to a reference plane that includes the rotation axis, in a plane orthogonal to the rotation axis, a portion occupying at least half of the total area of the m first voids is located on the first side a portion occupying at least half of the total area of the n second voids is located on the second side, and the width W1 in the radial direction of at least one of the m first voids and the width W2 in the radial direction of at least one of the n second voids satisfy W1 > W2. The shortest distance R1 from the rotation axis to the m first voids and the shortest distance R2 from the rotation axis to the n second voids satisfy R2 ≤ 1.15 × R1.

Description

Rotor, motor, compressor and refrigeration cycle device

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

[0002] The rotor has a rotor core with magnet insertion holes and permanent magnets arranged in the magnet insertion holes. To adjust the eccentricity of the rotor, a rotor core with an eccentric hole on one side of a reference plane including the rotation axis of the rotor core is known (see, for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2021-164292 (see FIG. 2)

[0004] Here, heat generated by friction between the shaft and bearings is transferred to the inner periphery of the rotor core. Because the eccentric hole in the rotor core acts as a resistance to heat transfer, heat transfer from the inner periphery to the outer periphery of the rotor core becomes uneven between the side with the eccentric hole and the side without the eccentric hole, which tends to result in uneven temperature distribution in the circumferential direction of the rotor core. As a result, the rotor core loses its roundness due to uneven thermal expansion, which can cause vibration or noise.

[0005] The present disclosure has been made to solve the above-mentioned problems, and aims to make the temperature distribution of a rotor core uniform.

[0006] The rotor disclosed herein is an annular rotor core extending circumferentially about a rotation axis, the rotor core having magnet insertion holes and permanent magnets disposed in the magnet insertion holes. The rotor core has m (m is an integer greater than or equal to 1) first air gaps and n (n is an integer greater than or equal to 1) second air gaps in a region between the inner circumference of the rotor core and the magnet insertion holes in a radial direction about the rotation axis. If one side of a reference plane including the rotation axis is defined as the first side and the other side is defined as the second side, then, in a plane perpendicular to the rotation axis, a portion occupying more than half of the total area of ​​the m first air gaps is located on the first side, and a portion occupying more than half of the total area of ​​the n second air gaps is located on the second side. The radial width W1 of at least one of the m first air gaps and the radial width W2 of at least one of the n second air gaps satisfy W1 > W2. The shortest distance R1 from the rotation axis to the m first gaps and the shortest distance R2 from the rotation axis to the n second gaps satisfy R2≦1.15×R1.

[0007] In the present disclosure, the rotor core is provided with a first gap and a second gap, and the widths W1 and W2 of the first gap and the second gap and the shortest distances R1 and R2 from the rotation shaft satisfy W1 > W2 and R2 ≦ 1.15 × R1, so that the heat transfer from the inner periphery to the outer periphery can be made more uniform on the first side and the second side, thereby making it possible to uniform the temperature distribution of the rotor core.

[0008] 1 is a cross-sectional view showing a motor according to a first embodiment; FIG. 2 is a cross-sectional view showing a rotor according to a first configuration example of the first embodiment; FIG. 3 is a longitudinal cross-sectional view showing the rotor of FIG. 2; FIG. 4 is a cross-sectional view showing a rotor according to a second configuration example of the first embodiment; FIG. 5 is a cross-sectional view showing a rotor according to a third configuration example of the first embodiment; FIG. 6 is a cross-sectional view showing a rotor according to a first comparative example; FIG. 7 is a graph showing an analysis result of the temperature distribution on the inner periphery of the rotor core according to the first comparative example when heat is applied to the inner periphery of the rotor core according to the first embodiment; FIG. 8 is a cross-sectional view showing a rotor according to a second comparative example; FIG. 9 is a graph showing an analysis result of the temperature distribution on the inner periphery of the rotor core according to the first embodiment when heat is applied to the inner periphery of the rotor core according to the second comparative example; 19A is a cross-sectional view showing a rotor according to a second embodiment, and FIG. 19B is a schematic diagram showing two first gaps. FIG. 19C is a graph showing an analysis result of the temperature distribution on the inner periphery of the rotor core when heat is applied to the inner periphery of the rotor core according to the second embodiment. FIG. 19D is a cross-sectional view showing a rotor according to a third embodiment. FIG. 19E is a graph showing an analysis result of the temperature distribution on the inner periphery of the rotor core when heat is applied to the inner periphery of the rotor core according to the third embodiment. FIG. 19F is a longitudinal sectional view showing a rotor according to a fourth embodiment. FIG. 19A is a cross-sectional view showing a rotor according to a first modified example, and FIG. 19B is a cross-sectional view showing a rotor according to a second modified example. FIG. 19C is a cross-sectional view showing another example of the rotor configuration. FIG. 19D is a longitudinal sectional view showing a compressor to which the motors of the respective embodiments and modified examples can be applied. FIG. 19E is a diagram showing a refrigeration cycle device including the compressor of FIG.

[0009] Embodiment 1. <Configuration of Motor 5> Figure 1 is a cross-sectional view showing a motor 5 according to embodiment 1. The motor 5 includes a shaft 25, a rotor 1 attached to the shaft 25, and an annular stator 3 surrounding the rotor 1. An air gap of 0.3 mm to 1.0 mm is provided between the stator 3 and the rotor 1. The stator 3 is fixed to the inside of a cylindrical shell 28 of a compressor 300 (Figure 19), for example.

[0010] Hereinafter, the center of rotation of the rotor 1 will be referred to as the rotation axis C1. The direction of the rotation axis C1 will be referred to as the "axial direction." The circumferential direction centered on the rotation axis C1 will be referred to as the "circumferential direction," and the radial direction centered on the rotation axis C1 will be referred to as the "radial direction." Furthermore, a cross-sectional view taken along a plane parallel to the rotation axis C1 will be referred to as a "longitudinal cross-sectional view," and a cross-sectional view taken along a plane perpendicular to the rotation axis C1 will be referred to as a "transverse cross-sectional view."

[0011] <Configuration of Stator 3> The stator 3 has an annular stator core 30 and a coil 35 wound around the stator core 30. The stator core 30 is made up of a plurality of electromagnetic steel plates stacked in the axial direction. The thickness of the electromagnetic steel plates is 0.1 mm to 0.7 mm, and is 0.35 mm, for example.

[0012] The stator core 30 has a yoke 31 extending in the circumferential direction and a plurality of teeth 32 extending radially inward from the yoke 31. Slots 33, which are spaces for accommodating coils 35, are formed between adjacent teeth 32.

[0013] Here, nine teeth 32 are provided at equal intervals in the circumferential direction. However, the number of teeth 32 is not limited to nine, and may be two or more. An insulating portion is provided between the stator core 30 and the coil 35. The insulating portion is, for example, the insulating portion 34 shown in FIG. 19 or an insulating film.

[0014] A groove 30c is formed on the outer periphery of the yoke 31, forming a refrigerant flow path between the shell 28 and the yoke 31. Crimped portions 30a are formed on both circumferential sides of the groove 30c in the yoke 31 for fixing the electromagnetic steel sheets that make up the stator core 30 to one another. A recess 30b is formed radially inside the groove 30c for fixing an insulating portion to the stator core 30. The arrangement of the crimped portions 30a, recess 30b, and groove 30c is arbitrary.

[0015] The coils 35 are made of magnet wire. The magnet wire is a conductor made of copper or aluminum covered with an insulating coating. The coils 35 are wound around the teeth 32 via insulating parts. The coils 35 are wound using concentrated winding, in which the magnet wire is wound around each tooth 32 individually.

[0016] The wire diameter and number of turns of the coil 35 are determined based on the characteristics required of the motor 5 (e.g., rotation speed, torque, etc.), voltage specifications, the cross-sectional area of ​​the slot 33, etc. For example, a magnet wire with a wire diameter of 1.0 mm is wound around one tooth 32 about 80 turns.

[0017] The stator core 30 may be configured by combining split cores in the circumferential direction, each split core being divided into individual teeth 32. In this case, the stator core 30 is spread out in a strip shape, and the coils 35 are wound around each tooth 32 via an insulating portion. Thereafter, the stator core 30 is bent into an annular shape and both ends are welded, thereby obtaining the stator 3.

[0018] <Configuration of Rotor 1> Fig. 2 is a cross-sectional view showing a first configuration example of the rotor 1. The rotor 1 shown in Fig. 2 has a rotor core 10 and permanent magnets 20. The rotor core 10 is made up of a plurality of electromagnetic steel plates stacked in the axial direction. The thickness of the electromagnetic steel plates is 0.1 mm to 0.7 mm or less, and is 0.35 mm, for example.

[0019] Rotor core 10 has an inner periphery 13 and an outer periphery 14. Both inner periphery 13 and outer periphery 14 extend circumferentially, for example, around rotation axis C1. A shaft 25 is fixed to inner periphery 13 of rotor core 10. The fixing method may be, for example, shrink fitting or press fitting.

[0020] A total of h (h is an integer of 2 or greater) magnet insertion holes 11 are formed along the outer periphery 14 of the rotor core 10. The h magnet insertion holes 11 are arranged at equal intervals in the circumferential direction. One permanent magnet 20 is inserted into each magnet insertion hole 11.

[0021] The permanent magnet 20 is flat and has a width in the circumferential direction and a thickness in the radial direction. The permanent magnet 20 is magnetized in the thickness direction. The permanent magnet 20 is made of, for example, a rare earth magnet. For example, a neodymium magnet containing neodymium (Nd), iron (Fe), and boron (B) is used as the rare earth magnet.

[0022] The permanent magnet 20 placed in each magnet insertion hole 11 constitutes one magnetic pole. The circumferential center of the magnet insertion hole 11 is the pole center. An inter-pole section is formed between adjacent magnet insertion holes 11. A radial line passing through the pole center is called the magnetic pole center line P. A radial line passing through the inter-pole section is called the inter-pole center line M.

[0023] Flux barriers 12 serving as leakage flux suppression holes are formed on both circumferential sides of each magnet insertion hole 11. Thin-walled portions are formed between the flux barriers 12 and the outer periphery 14 of the rotor core 10. The thickness of the thin-walled portions is set to be equal to the thickness of the electromagnetic steel plates, for example, in order to suppress leakage flux between adjacent magnetic poles.

[0024] Here, the number (h) of magnet insertion holes 11 is six, and the number of permanent magnets 20 is also six. Therefore, the number of poles p of the rotor 1 is 6. However, the number of poles p of the rotor 1 is not limited to 6, and may be 2 or more.

[0025] Also, although one permanent magnet 20 is placed in each magnet insertion hole 11 here, two or more permanent magnets 20 may be placed in each magnet insertion hole 11. Also, although the magnet insertion holes 11 extend linearly here, they may extend in a V-shape, for example (see FIG. 17(A)).

[0026] Also, here, the number h of magnet insertion holes 11 is equal to the number p of poles of the rotor 1, but if two magnet insertion holes 11 are formed per magnetic pole, the number h of magnet insertion holes 11 becomes equal to twice the number p of poles of the rotor 1 (see Figure 17 (B)).

[0027] The rotor 1 has m air gaps A1 to Am and n air gaps B1 to Bn in the radial region between the inner periphery 13 and the magnet insertion hole 11. The air gaps A1 to Am are also referred to as first air gaps, and the air gaps B1 to Bn are also referred to as second air gaps.

[0028] Both m and n are integers of 1 or greater. In the example shown in FIG. 2, both m and n are 3, but they may be any number greater than or equal to 1. Furthermore, m and n do not have to be the same number. When there is no particular need to distinguish between the voids A1 to Am, they will be described as void A. Similarly, when there is no particular need to distinguish between the voids B1 to Bn, they will be described as void B.

[0029] The plane passing through the rotation axis C1 is referred to as the reference plane T. The reference plane T is set in consideration of the amount of eccentricity to be applied to the rotor 1. One side of the reference plane T is referred to as the first side S1. The other side of the reference plane T is referred to as the second side S2.

[0030] The m voids A1 to Am are formed on a first side S1 with respect to the reference plane T. The n voids B1 to Bn are formed on a second side S2 with respect to the reference plane T.

[0031] The voids A1, A2, and A3 shown in Fig. 2 are arranged in this order counterclockwise in the drawing. Similarly, the voids B1, B2, and B3 shown in Fig. 2 are arranged in this order counterclockwise in the drawing.

[0032] In the example shown in Figure 2, the voids A1 to A3 have the same shape and the same dimensions. Similarly, the voids B1 to B3 have the same shape and the same dimensions. However, the shape or dimensions of at least one of the voids A1 to Am may be different from the others. Similarly, the shape or dimensions of at least one of the voids B1 to Bn may be different from the others.

[0033] The gap A has an inner peripheral edge 51 on the inner circumference 13 side, an outer peripheral edge 52 on the outer circumference 14 side, and side edges 53 on both circumferential sides. Both the inner peripheral edge 51 and the outer peripheral edge 52 extend in an arc shape centered on the rotation axis C1. The side edge 53 extends in a curved manner in the radial direction, and more specifically, extends in an arc shape centered within the gap A.

[0034] Ribs 15, which are iron core portions, are formed between adjacent gaps A. The ribs 15 are sandwiched from both sides in the circumferential direction by the side edges 53 of adjacent gaps A. The width D1 of the rib 15 is narrowest at its radial center. The ribs 15 are also referred to as first ribs.

[0035] The gap B has an inner peripheral edge 61 on the inner circumference 13 side, an outer peripheral edge 62 on the outer circumference 14 side, and side edges 63 on both circumferential sides. Both the inner peripheral edge 61 and the outer peripheral edge 62 extend in an arc shape centered on the rotation axis C1. The side edge 63 extends in a curved manner in the radial direction, and more specifically, extends in an arc shape centered within the gap B.

[0036] Ribs 16, which are iron core portions, are formed between adjacent gaps B. The ribs 16 are sandwiched from both circumferential sides by the side edges 63 of adjacent gaps B. The width D2 of the ribs 16 is narrowest at the radial center. The ribs 16 are also referred to as second ribs.

[0037] A rib 17, which is an iron core portion, is also formed between the gap A and the gap B. The rib 17 is located on the reference plane T. The rib 17 is also referred to as a third rib.

[0038] Gap A has a width W1 in the radial direction. Width W1 is the distance from inner peripheral edge 51 to outer peripheral edge 52. Gap B has a width W2 in the radial direction. Width W2 is the distance from inner peripheral edge 61 to outer peripheral edge 62. Width W1 of gap A is wider than width W2 of gap B. In other words, W1 > W2 holds.

[0039] In the first embodiment, the area of ​​each gap A is larger than the area of ​​each gap B in a plane perpendicular to the rotation axis C1. Therefore, the total area of ​​gaps A1 to A3 is larger than the total area of ​​gaps B1 to B3. Therefore, the weight of the first side S1 of the rotor core 10 is lighter than the weight of the second side S2. This allows the eccentricity of the rotor 1 to be adjusted.

[0040] Furthermore, the shortest distance R1 from the rotation axis C1 to the gap A and the shortest distance R2 from the rotation axis C1 to the gap B satisfy R2≦1.15×R1, the reason for which will be described later.

[0041] The gap A has a length L1 in the circumferential direction. The length L1 is the circumferential distance between two side edges 53 of the gap A. The gap B has a length L2 in the circumferential direction. The length L2 is the circumferential distance between two side edges 63 of the gap B. Although the length L1 of the gap A and the length L2 of the gap B are shown to be the same in FIG. 2 , they may be different.

[0042] The rib 15 has a width D1 in the circumferential direction. The width D1 is the shortest circumferential distance between adjacent gaps A. The rib 16 has a width D2 in the circumferential direction. The width D2 is the shortest circumferential distance between adjacent gaps B. The circumferential width D1 of the rib 15 and the circumferential width D2 of the rib 16 are the same in FIG. 2 , but they may be different.

[0043] In Fig. 2, all of the voids A1 to Am are formed on the first side S1, but at least one of the voids A1 to Am may protrude onto the second side S2 (see Fig. 18A). Similarly, in Fig. 2, all of the voids B1 to Bn are formed on the second side S2, but at least one of the voids B1 to Bn may protrude onto the first side S1 (see Fig. 18B).

[0044] In other words, in a plane perpendicular to the axial direction, if the portion that occupies more than half of the total area of ​​the gaps A1 to Am is located on the first side S1 with respect to the reference plane T, and the portion that occupies more than half of the total area of ​​the gaps B1 to Bn is located on the second side S2 with respect to the reference plane T, then the eccentricity of the rotor 1 can be adjusted.

[0045] 3 is a longitudinal cross-sectional view showing the rotor 1. The gap A extends in the axial direction from a first end face 10a, which is one axial end face of the rotor core 10, to a second end face 10b, which is the other axial end face of the rotor core 10. The radial width W1 of the gap A is constant. Similarly, the gap B extends in the axial direction from the first end face 10a to the second end face 10b of the rotor core 10. The radial width W2 of the gap B is constant.

[0046] Fig. 4 is a cross-sectional view showing a rotor 1A according to a second configuration example of embodiment 1. In the rotor 1A shown in Fig. 4, the rotor core 10 has six gaps A1 to A6 on a first side S1 relative to the reference plane T, and six gaps B1 to B6 on a second side S2.

[0047] That is, in the rotor 1A, m = n = 6. Therefore, the circumferential length of the gap A in the rotor 1A is shorter than the circumferential length of the gap A in the rotor 1 shown in Fig. 2, and the circumferential length of the gap B in the rotor 1A is shorter than the circumferential length of the gap B in the rotor 1 shown in Fig. 2. In other respects, the rotor 1A is configured similarly to the rotor 1 shown in Fig. 2.

[0048] 4, the radial width W1 of the gap A and the radial width W2 of the gap B also satisfy W1 > W2. Furthermore, the shortest distance R1 from the rotation axis C1 to the gap A and the shortest distance R2 from the rotation axis C1 to the gap B also satisfy R2 ≦ 1.15 × R1.

[0049] Fig. 5 is a cross-sectional view showing a rotor 1B according to a second configuration example of embodiment 1. In the rotor 1B shown in Fig. 5, the rotor core 10 has four gaps A1 to A4 on a first side S1 relative to the reference plane T, and four gaps B1 to B4 on a second side S2.

[0050] That is, in rotor 1B, m = n = 4. Therefore, the circumferential length of gap A in rotor 1B is shorter than the circumferential length of gap A in rotor 1 shown in Fig. 2, and the circumferential length of gap B in rotor 1B is shorter than the circumferential length of gap B in rotor 1 shown in Fig. 2. Furthermore, in gap A in rotor 1B, side edge 53 is formed in a straight line. In other respects, rotor 1B is configured similarly to rotor 1 shown in Fig. 2.

[0051] 5, the radial width W1 of the gap A and the radial width W2 of the gap B also satisfy W1 > W2. Furthermore, the shortest distance R1 from the rotation axis C1 to the gap A and the shortest distance R2 from the rotation axis C1 to the gap B also satisfy R2 ≦ 1.15 × R1.

[0052] <Operation> The operation of the first embodiment will be described in comparison with comparative examples 1 and 2. Fig. 6 is a schematic diagram showing a rotor 1M of comparative example 1. In the rotor core 10 of the rotor 1M of comparative example 1, in order to adjust the amount of eccentricity, four gaps A1 to A4 are formed on a first side S1 with respect to the reference plane T in a region between the inner periphery 13 and the magnet insertion hole 11 in the radial direction. On the other hand, no gaps are formed on a second side S2 with respect to the reference plane T.

[0053] Since the gaps A1 to A4 are formed on the first side S1 and no gap is formed on the second side S2, the weight of the rotor core 10 is greater on the second side S2 than on the first side S1, making it possible to adjust the eccentricity of the rotor 1M. In other words, it can function similarly to a balance weight.

[0054] In the motor 5 used in the compressor 300 (FIG. 19) or the like, heat is generated due to friction between the shaft 25 and the bearings of the compression mechanism 301. The heat of the shaft 25 is transferred to the inner periphery 13 of the rotor core 10 and moves within the rotor core 10 from the inner periphery 13 to the outer periphery 14.

[0055] On the first side S1 of the rotor core 10, the heat transfer from the inner periphery 13 to the outer periphery 14 is hindered by gaps A1 to A4, but on the second side S2 of the rotor core 10, there is little to hinder the heat transfer from the inner periphery 13 to the outer periphery 14.

[0056] This causes a difference in the amount of temperature rise between the first side S1 and the second side S2 of the rotor core 10, resulting in an uneven temperature distribution in the circumferential direction. As a result, the uneven thermal expansion of the rotor core 10 can cause a loss of circularity, which can lead to vibration or noise. Alternatively, this can lead to damage to the rotor core 10 or the permanent magnets 20.

[0057] FIG. 7 is a graph showing the analysis results of the temperature distribution of the inner periphery 13 of the rotor core 10 when a constant amount of heat is continuously applied to the inner periphery 13 of the rotor 1M (FIG. 6) of Comparative Example 1.

[0058] The horizontal axis in Fig. 7 represents the angle from a reference point Q centered on the rotation axis C1. The vertical axis in Fig. 7 represents the temperature. As shown in Fig. 6, the reference point Q is the intersection point on the side where the gap A1 is provided (i.e., the right side in Fig. 6) of the two intersection points between the inner circumference 13 and the reference plane T. The angle is measured counterclockwise in Fig. 6. The angle range from 0 to 180 degrees from the reference point Q corresponds to the first side S1, and the angle range from 180 to 360 degrees corresponds to the second side S2.

[0059] 7, the temperature of the rotor core 10 of the rotor 1M is high when the angle from the reference point Q is in the range of 0 to 180 degrees (i.e., the first side S1), and low when the angle is in the range of 180 to 360 degrees (i.e., the second side S2). In particular, the maximum temperature Tmax occurs at positions where the angle from the reference point Q is 70 degrees and 110 degrees, and the minimum temperature Tmin occurs at a position where the angle from the reference point Q is 270 degrees. The ratio of the maximum temperature Tmax to the minimum temperature Tmin (i.e., Tmax / Tmin) is 1.45.

[0060] This is because when the angle from the reference point Q is in the range of 0 to 180 degrees (i.e., the first side S1), the gap A prevents heat from moving from the inner circumference 13 to the outer circumference 14, and heat tends to remain in the area surrounding the inner circumference 13, whereas when the angle from the reference point Q is in the range of 180 to 360 degrees (i.e., the second side S2), heat tends to move from the inner circumference 13 to the outer circumference 14.

[0061] Figure 8 is a graph showing the analysis results of the temperature distribution on the inner periphery 13 of the rotor core 10 when a constant amount of heat is continuously applied to the inner periphery 13 of the rotor 1 (Figure 2) according to the first embodiment. In the analysis, the shortest distances R1 and R2 from the rotation axis C1 to the gaps A and B are set to satisfy R2 / R1 = 0.947. The horizontal axis of Figure 8 represents the angle from the reference point Q centered on the rotation axis C1. The vertical axis of Figure 8 represents the temperature.

[0062] 8, the temperature of the rotor core 10 of the rotor 1 is high when the angle from the reference point Q is in the range of 0 to 180 degrees (i.e., the first side S1), and is low when the angle is in the range of 180 to 360 degrees (i.e., the second side S2). However, the ratio of the maximum temperature Tmax to the minimum temperature Tmin (i.e., Tmax / Tmin) is 1.22, which is lower than that of Comparative Example 1.

[0063] In the rotor 1 of the first embodiment, heat transfer from the inner periphery 13 toward the outer periphery 14 of the rotor core 10 is impeded on the first side S1 by the gap A, and on the second side S2 by the gap B. As a result, heat can be retained evenly in the circumferential direction in the region surrounding the inner periphery 13 of the rotor core 10, thereby making the temperature distribution of the rotor core 10 uniform.

[0064] In Figure 8, the temperature at angles from the reference point Q of 0 to 180 degrees (i.e., the first side S1) is higher than the temperature at angles from 180 to 360 degrees (i.e., the second side S2) because the width W1 of the gaps A1 to A3 is wider than the width W2 of the gaps B1 to B3.

[0065] Next, the relationship between the shortest distance R1 from the rotation axis C1 to the gap A and the shortest distance R2 from the rotation axis C1 to the gap B will be described.

[0066] 9 is a schematic diagram showing a rotor 1N of Comparative Example 2. In the rotor core 10 of the rotor 1N of Comparative Example 2, four gaps A1 to A4 are formed on a first side S1 relative to the reference plane T, and four gaps B1 to B4 are formed on a second side S2. That is, like the rotor 1B shown in FIG. 5, m = n = 4.

[0067] The gaps A1 to A4 of the rotor 1N are formed similarly to the gaps A1 to A4 of the rotor 1B in Fig. 5. The gaps B1 to B4 of the rotor 1N are formed similarly to the gaps B1 to B4 of the rotor 1B in Fig. 5. However, the shortest distance R2 from the rotation axis C1 to the gaps B1 to B4 is longer than the shortest distance R1 from the rotation axis C1 to the gaps A1 to A4. More specifically, the shortest distance R2 is 1.20 times the shortest distance R1, and R2 = R1 × 1.20 holds true.

[0068] 10 is a graph showing the analysis results of the temperature distribution on the inner periphery 13 of the rotor core 10 when a constant amount of heat is continuously applied to the inner periphery 13 of the rotor 1N (FIG. 9) of Comparative Example 2. As described above, the shortest distances R1 and R2 from the rotation axis C1 to the gaps A and B satisfy R2 / R1 = 1.20. The horizontal axis of FIG. 10 represents the angle from the reference point Q centered on the rotation axis C1. The vertical axis of FIG. 10 represents the temperature.

[0069] 10, the temperature of rotor core 10 is high when the angle from reference point Q is in the range of 0 to 180 degrees (i.e., first side S1) and low when the angle is in the range of 180 to 360 degrees (i.e., second side S2). In addition, the ratio of maximum temperature Tmax to minimum temperature Tmin (i.e., Tmax / Tmin) is 1.247.

[0070] 8 and 10, the value of Tmax / Tmin (FIG. 8) in embodiment 1 is smaller than the value of Tmax / Tmin (FIG. 10) in comparative example 2. This is because the shorter the shortest distance R2 from rotation axis C1 to gap B, the more heat traveling from inner periphery 13 to outer periphery 14 is retained on the inner periphery 13 side.

[0071] 11A is a graph showing the relationship between the ratio of the maximum temperature Tmax to the minimum temperature Tmin (Tmax / Tmin) and the ratio of the shortest distance R2 to the shortest distance R1 (R2 / R1). Fig. 11A shows the range in which R2 / R1 is 1 or greater.

[0072] As shown in Figure 11 (A), as R2 / R1 increases, the value of Tmax / Tmin increases. The curve showing the relationship between R2 / R1 and Tmax / Tmin is approximated by a straight line N1 with a positive slope. When R2 / R1 exceeds 1.15, the rate of increase of Tmax / Tmin relative to an increase in R2 / R1 becomes large. The point where R2 / R1 = 1.15 corresponds to the inflection point.

[0073] From this result, it can be seen that when R2 / R1≦1.15 is satisfied, the effect of reducing the value of Tmax / Tmin, that is, the effect of making the temperature distribution of rotor core 10 uniform, is significant.

[0074] 11B is a graph showing the relationship between the ratio of the maximum temperature Tmax to the minimum temperature Tmin (Tmax / Tmin) and the ratio of the shortest distance R2 to the shortest distance R1 (R2 / R1). FIG. 11B shows the range where R2 / R1 is 0.9 or more.

[0075] As shown in Figure 11 (B), as R2 / R1 decreases, the value of Tmax / Tmin decreases. When R2 / R1 becomes 1 or less, the rate of decrease of Tmax / Tmin relative to the decrease in R2 / R1 increases. Furthermore, when R2 / R1 becomes 0.95 or less, the rate of decrease of Tmax / Tmin relative to the decrease in R2 / R1 decreases again. The point where R2 / R1 = 1.00 and the point where R2 / R1 = 0.95 both correspond to inflection points.

[0076] From the results shown in Figures 11(A) and (B), it can be said that the effect of uniforming the temperature distribution in rotor core 10 is large when R2 / R1≦1.15, and is particularly large when R2 / R1<1.

[0077] Therefore, in order to make the temperature distribution of rotor core 10 uniform, it is desirable that R2≦1.15×R1 be satisfied, and it is more desirable that R2<R1 be satisfied.

[0078] Furthermore, as can be seen from Figure 11 (B), in the range where R2 / R1 is less than 0.95, further improvement in the effect of uniforming the temperature distribution in the rotor core 10 cannot be expected, so it is particularly desirable that 0.95 x R1 ≤ R2 < R1 holds.

[0079] Here, the heat applied to inner periphery 13 of rotor core 10 has been described as frictional heat with the bearing of compression mechanism 301 (FIG. 19), but heat is also applied to expand the inner diameter of inner periphery 13 in the shrink-fitting process for fixing shaft 25 to rotor core 10. In this case, too, gaps A1-Am and gaps B1-Bn suppress heat transfer from inner periphery 13 to outer periphery 14, thereby making it possible to homogenize the temperature distribution in rotor core 10.

[0080] As described above, in embodiment 1, the temperature distribution of rotor core 10 can be made uniform, thereby suppressing vibration and noise caused by uneven thermal expansion and preventing damage to rotor core 10 and permanent magnets 20.

[0081] Furthermore, even if a rare earth magnet, which is prone to demagnetization at high temperatures, is used as the permanent magnet 20, the uniform temperature distribution in the rotor core 10 suppresses local temperature increases in the permanent magnet 20, thereby suppressing the occurrence of thermal demagnetization.

[0082] In addition to the gaps A1 to Am and the gaps B1 to Bn, the magnet insertion holes 11 also act as resistance to heat transfer in the rotor core 10. For this reason, it is desirable to form the gaps A1 to Am according to the positions of the magnet insertion holes 11 on the first side S1, and to form the gaps B1 to Bn according to the positions of the magnet insertion holes 11 on the second side S2.

[0083] Therefore, it is desirable that the number m of gaps A1 to Am be equal to or greater than half the number p of poles (i.e., the number of pole pairs), and the number n of gaps B1 to Bn be equal to or greater than half the number p of poles. This makes it easy to form gaps A1 to Am and gaps B1 to Bn according to the positions of magnet insertion holes 11, and can enhance the effect of uniforming the temperature distribution in rotor core 10.

[0084] 2 and other figures, the radial widths of the gaps A1 to Am are the same, and the radial widths of the gaps B1 to Bn are the same. However, the radial widths of the gaps A1 to Am do not necessarily have to be the same, and the radial widths of the gaps B1 to Bn do not necessarily have to be the same. It is sufficient that the radial width W1 of at least one of the gaps A1 to Am and the radial width W2 of at least one of the gaps B1 to Bn satisfy W1 > W2.

[0085] 2 and other figures, the gaps A1 to Am are equidistant from the rotation axis C1, and the gaps B1 to Bn are equidistant from the rotation axis C1. However, the gaps A1 to Am do not have to be equidistant from the rotation axis C1, and the gaps B1 to Bn do not have to be equidistant from the rotation axis C1. In this case as well, the distance from the rotation axis C1 to the closest gap A is the shortest distance R1, and the distance from the rotation axis C1 to the closest gap B is the shortest distance R2.

[0086] Effect of the Embodiment As described above, the rotor 1 according to the first embodiment includes a rotor core 10 having magnet insertion holes 11 and permanent magnets 20 disposed in the magnet insertion holes 11. The rotor core 10 has m (m is an integer greater than or equal to 1) air gaps A1 to Am and n (n is an integer greater than or equal to 1) air gaps B1 to Bn in a region between the inner periphery 13 and the magnet insertion holes 11 in the radial direction. If one side of a reference plane T including the rotation axis C1 is designated as a first side S1 and the other side is designated as a second side S2, then, in a plane perpendicular to the rotation axis C1, a portion occupying more than half of the total area of ​​the air gaps A1 to Am is located on the first side S1, and a portion occupying more than half of the total area of ​​the air gaps B1 to Bn is located on the second side S2. The radial width W1 of at least one of the air gaps A1 to Am and the radial width W2 of at least one of the air gaps B1 to Bn satisfy the relationship W1 > W2. The shortest distance R1 from the rotation axis C1 to the gaps A1 to Am and the shortest distance R2 from the rotation axis C1 to the gaps B1 to Bn satisfy R2≦1.15×R1.

[0087] In this way, gaps A1 to Am and gaps B1 to Bn are provided in rotor core 10, and because W1 > W2 and R2 ≦ 1.15 × R1 are satisfied, heat transfer from inner periphery 13 to outer periphery 14 of rotor core 10 can be made more uniform on first side S1 and second side S2, thereby making it possible to uniform the circumferential temperature distribution of rotor core 10. Furthermore, uniforming the temperature distribution in rotor core 10 suppresses local temperature increases in permanent magnets 20, and thermal demagnetization of permanent magnets 20 can also be suppressed.

[0088] Furthermore, if the shortest distances R1, R2 from the rotation axis C1 to the gaps A, B satisfy R2 < R1 (more preferably 0.95 x R1 ≦ R2 < R1), the effect of uniformly distributing the temperature in the rotor core 10 can be further enhanced.

[0089] Furthermore, by making the number m of gaps A1 to Am equal to or greater than the number of pole pairs (i.e., m≧p / 2) and making the number n of gaps B1 to Bn equal to or greater than the number of pole pairs (i.e., n≧p / 2), it becomes easier to form gaps A1 to Am and gaps B1 to Bn according to the position of the magnet insertion hole 11, thereby enhancing the effect of uniforming the temperature distribution in the rotor core 10.

[0090] 12A is a diagram showing a rotor 1C according to embodiment 2. The rotor 1C according to embodiment 2 differs from the rotor 1 according to embodiment 1 in the shape of the gaps A1 to Am serving as the first gaps.

[0091] As shown in Figure 12 (A), the rotor core 10 of the rotor 1C has gaps A1 to Am as first gaps and gaps B1 to Bn as second gaps in the radial region between the inner circumference 13 and the magnet insertion hole 11.

[0092] As described in the first embodiment, the voids A1 to Am are located on the first side S1 with respect to the reference plane T, and the voids B1 to Bn are located on the second side S2 with respect to the reference plane T. In the example shown in Fig. 12(A), both m and n are 4, but are not limited to 4. Furthermore, m and n do not have to be the same number.

[0093] 12A, the rib 15 between the gaps A2 and A3 is located on the magnetic pole center line P of the central magnetic pole of the three magnetic poles on the first side S1. In other words, the rib 15 between the gaps A2 and A3 faces the circumferential center of the central magnet insertion hole 11 of the three magnet insertion holes 11 on the first side S1.

[0094] 12B is an enlarged schematic diagram showing gaps A2 and A3 and the rib 15 therebetween. Gap A2 has an inner peripheral edge 51 on the inner periphery 13 side, an outer peripheral edge 52 on the outer periphery 14 side, a side edge 53a on the magnetic pole center line P side, and a side edge 53b on the opposite side.

[0095] The gap A2 has an asymmetric shape with respect to the line V. The line V is a line passing through the rotation axis C1 and bisects the area of ​​the gap A2 in a plane perpendicular to the axial direction. The side edge 53a of the gap A2 is curved so that the circumferential width of the rib 15 between the gap A2 and the gap A3 increases radially outward.

[0096] The side edge 53b of the gap A2 extends radially outward in a straight line from the end of the inner peripheral edge 51. A portion 53c of the side edge 53b that connects with the outer peripheral edge 52 is curved. However, the side edge 53b of the gap A2 may extend entirely in a straight line or entirely in a curved line. Both the inner peripheral edge 51 and the outer peripheral edge 52 extend in an arc shape centered on the rotation axis C1.

[0097] The gap A3 has a shape symmetrical to the gap A2 across the rib 15. That is, the gap A3 has a shape asymmetrical with respect to the line V. The line V is a line passing through the rotation axis C1 and is a line that bisects the area of ​​the gap A3 in a plane perpendicular to the axial direction.

[0098] The circumferential width D1 of the rib 15 between the gaps A2 and A3 is wider on the radially outer side than on the radially inner side. ｉｎ The width D1 of the radially outer end of the rib 15 is ｏｕｔ is wider.

[0099] 12A, the gaps A1 and A4 are formed in the same manner as the gaps A1 and A4 shown in FIG. 5 of the first embodiment. The gaps B1 to B4 are formed in the same manner as the gaps B1 to B3 shown in FIG. 5 of the first embodiment.

[0100] Fig. 13 is a graph showing the analysis results of the temperature distribution on the inner periphery 13 of the rotor core 10 when a constant amount of heat is continuously applied to the inner periphery 13. In the analysis, the shortest distances R1 and R2 from the rotation axis C1 to the gaps A and B are set to satisfy R2 / R1 = 0.95. The horizontal axis of Fig. 13 represents the angle from the reference point Q centered on the rotation axis C1. The vertical axis of Fig. 13 represents the temperature.

[0101] 13, the temperature of rotor core 10 reaches a maximum temperature Tmax at positions where the angles from reference point Q are 70 degrees and 110 degrees, and reaches a minimum temperature Tmin at a position where the angle from reference point Q is 270 degrees. The ratio of maximum temperature Tmax to minimum temperature Tmin (i.e., Tmax / Tmin) is 1.190.

[0102] In rotor core 10, in addition to gaps A1 to Am and gaps B1 to Bn, magnet insertion holes 11 also act as resistance to heat transfer. In the second embodiment, the width of rib 15 between gaps A2 and A3 increases radially outward, so heat passing through rib 15 spreads to both sides in the circumferential direction. As a result, heat passing through rib 15 is dispersed circumferentially and can be further dispersed by magnet insertion holes 11, making the temperature distribution in rotor core 10 more uniform.

[0103] Here, the gaps A2 and A3 have an asymmetric shape so that the width of the rib 15 located on the magnetic pole center line P increases radially outward. However, if a through hole is formed in the rotor core 10 as a refrigerant flow path or a rivet hole, the width of the rib 15 may increase toward the through hole.

[0104] Furthermore, if at least one of the gaps A1 to Am has the asymmetric shape (FIG. 12B), it is possible to obtain the effect of dispersing heat passing through the rib 15 in the circumferential direction. Furthermore, although the case where the gap A has an asymmetric shape has been described here, the gap B may also have an asymmetric shape.

[0105] As described above, the number m of voids A and the number n of voids B are not limited to 4, but in order to form ribs 15 between adjacent voids A, it is desirable that the number m of voids A be 2 or more.

[0106] Except for the points mentioned above, the rotor 1C of the second embodiment is configured similarly to the rotor 1 of the first embodiment.

[0107] As described above, in embodiment 2, at least one of the gaps A1 to Am in the rotor core 10 is formed asymmetrically with respect to the line V, which is a straight line passing through the rotation axis C1 and which bisects the gap area in a plane perpendicular to the axial direction, so that the heat passing through the rib 15 adjacent to the gap A can be dispersed circumferentially, thereby making the temperature distribution in the rotor core 10 uniform.

[0108] Furthermore, since the circumferential width of the rib 15 between two adjacent gaps A is wider at the radially outer end of the rib 15 than at the radially inner end of the rib 15, the heat passing through the rib 15 can be dispersed more effectively, thereby enhancing the effect of uniforming the temperature distribution in the rotor core 10.

[0109] Embodiment 3 Figure 14 is a diagram showing a rotor 1D of embodiment 3. The rotor 1D of embodiment 3 differs from the rotor 1 of embodiment 1 in the lengths of the gaps B1 to Bn.

[0110] As shown in Figure 14, the rotor core 10 of the rotor 1D has gaps A1 to Am as first gaps and gaps B1 to Bn as second gaps in the radial region between the inner circumference 13 and the magnet insertion hole 11.

[0111] As described in the first embodiment, the gaps A1 to Am are located on the first side S1 with respect to the reference plane T, and the gaps B1 to Bn are located on the second side S2 with respect to the reference plane T. In the example shown in Fig. 15, m is 4 and n is 3, but m and n are not limited to these numerical values.

[0112] The gap B1 has a length L21 in the circumferential direction, the gap B2 has a length L22 in the circumferential direction, and the gap B3 has a length L23 in the circumferential direction. The length L22 of the gap B2 is longer than the length L21 of the gap B1 and longer than the length L23 of the gap B3. That is, L22 > L21 and L22 > L23 are established. That is, among the gaps B1, B2, and B3 on the second side S2, the length L22 of the gap B2 located in the center is the longest.

[0113] Fig. 15 is a graph showing the analysis results of the temperature distribution in the rotor core 10 when a constant amount of heat is continuously applied to the inner periphery 13. In the analysis, the shortest distances R1 and R2 from the rotation axis C1 to the gaps A and B are set so as to satisfy R2 / R1 = 1.0. The horizontal axis of Fig. 16 represents the angle from the reference point Q centered on the rotation axis C1. The vertical axis of Fig. 16 represents the temperature.

[0114] In Figure 8 described in embodiment 1, the temperature of rotor core 10 was high in the angle range of 0 to 180 degrees from reference point Q (i.e., first side S1) and low in the angle range of 180 to 360 degrees (i.e., second side S2).

[0115] In contrast, in the third embodiment, as shown in Fig. 15, the temperature at the position at an angle of 270 degrees from the reference point Q rises to a level equivalent to the maximum temperature Tmax. This is because the length L22 of the gap B2 formed at the position at an angle of 270 degrees from the reference point Q is longer than the lengths L21 and L23 of the other gaps B1 and B3.

[0116] Because the length L22 of the gap B2 is long, the gap B2 prevents heat from moving from the inner periphery 13 to the outer periphery 14, and the heat is retained in the region surrounding the inner periphery 13. As a result, the temperature distribution of the rotor core 10 is made more uniform.

[0117] 14, the length L22 of the central gap B2 among the gaps B1 to B3 is longer than the lengths L21 and L23 of the other gaps B1 and B3, but the present invention is not limited to this example. The length of the gap B may be increased at a location where heat transfer from the inner periphery 13 to the outer periphery 14 of the rotor core 10 is greatest.

[0118] Except for the points mentioned above, the rotor 1D of the third embodiment is configured similarly to the rotor 1 of the first embodiment.

[0119] As described above, in the third embodiment, the circumferential length of at least one gap B (e.g., gap B2) is longer than the circumferential lengths of the other gaps B (e.g., gaps B1 and B3). Therefore, by providing gaps B with a long circumferential length at locations where heat transfer from inner periphery 13 to outer periphery 14 is significant, the temperature distribution of rotor core 10 can be made more uniform.

[0120] 16 is a longitudinal cross-sectional view showing a rotor 1E according to embodiment 4. The rotor 1E according to embodiment 4 differs from the rotor 1 according to embodiment 1 (FIGS. 2 and 3) in that the rotor core 10 has a first core portion 81 and a second core portion 82, and the arrangements of the gaps A1 to Am and the gaps B1 to Bn are different between the first core portion 81 and the second core portion 82.

[0121] 16, rotor core 10 has a first core portion 81 and a second core portion 82 in the axial direction. The orientation of the electromagnetic steel sheets around rotation axis C1 differs by 180 degrees between first core portion 81 and second core portion 82. The number m of air gaps A1 to Am and the number n of air gaps B1 to Bn are the same (i.e., m = n).

[0122] The gap A of the first core portion 81 and the gap B of the second core portion 82 are continuous in the axial direction. Similarly, the gap B of the first core portion 81 and the gap A of the second core portion 82 are continuous in the axial direction. In other words, the first side S1 and the second side S2 of the first core portion 81 and the second core portion 82 are reversed.

[0123] As described in the first embodiment, the radial width W1 of the gap A is wider than the radial width W2 of the gap B. Therefore, the gaps A and B, which are continuous in the axial direction, form a flow path whose cross-sectional area changes midway.

[0124] In the rotor 1 shown in Figure 3 of the first embodiment described above, both gaps A and B axially penetrate the rotor core 10. Because gaps A and B have different radial widths W1 and W2, the rotational balance of the rotor 1 may change depending on the density of the refrigerant used. The rotational balance of the rotor 1 can be adjusted by attaching balance weights or the like, but this increases the number of parts and costs.

[0125] Therefore, in the fourth embodiment, the orientation of the electromagnetic steel sheets is changed between the first core portion 81 and the second core portion 82 of the rotor core 10, thereby making it possible to adjust the rotational balance of the rotor 1E.

[0126] For example, the rotational balance of the rotor 1E can be adjusted by adjusting the ratio between the axial length of the first core portion 81 of the rotor core 10 (i.e., the number of laminated electromagnetic steel sheets) and the axial length of the second core portion 82.

[0127] Here, the orientation of the electromagnetic steel sheets around the rotation axis C1 differs by 180 degrees between the first core portion 81 and the second core portion 82, but is not limited to 180 degrees. However, the position of the magnet insertion hole 11 of the first core portion 81 and the position of the magnet insertion hole 11 of the second core portion 82 must be aligned.

[0128] Therefore, when the number m of gaps A and the number n of gaps B are the same and the number of poles of rotor 1E is p, the positions of the first core portion 81, the second core portion 82, and the magnet insertion hole 11 can be aligned by rotating the electromagnetic steel plate of the second core portion 82 relative to the electromagnetic steel plate of the first core portion 81 by an angle equivalent to an integer multiple of 360 / p.

[0129] For example, if the number of poles p of rotor 1E is 6, the positions of the magnet insertion holes 11 in the first core portion 81 and the second core portion 82 can be aligned by rotating the electromagnetic steel plate of the second core portion 82 by 60 degrees, 120 degrees, 180 degrees, 240 degrees, or 300 degrees relative to the electromagnetic steel plate of the first core portion 81.

[0130] Except for the points mentioned above, the rotor 1E of the fourth embodiment is configured similarly to the rotor 1 of the first embodiment.

[0131] As described above, in the fourth embodiment, rotor core 10 has first core portion 81 and second core portion 82, and gap A of first core portion 81 and gap B of second core portion 82 are continuous in the axial direction, and gap B of first core portion 81 and gap A of second core portion 82 are continuous in the axial direction. Therefore, by adjusting the ratio of the axial lengths of first core portion 81 and second core portion 82, etc., it is possible to adjust the rotational balance of rotor 1E.

[0132] Modifications Next, modifications 1 and 2 of the respective embodiments will be described. Modifications 1 and 2 differ from the respective embodiments in the configurations of the magnet insertion holes 101 (111, 112) of the low core 10 and the permanent magnets 21, 22.

[0133] Fig. 17(A) is a cross-sectional view showing a rotor 1F of Modification 1. The rotor core 10 of the rotor 1F shown in Fig. 17(A) has h V-shaped magnet insertion holes 101 (h is an integer of 2 or greater). Here, h is 6, but it may be any number greater than or equal to 2. The magnet insertion holes 101 have a V-shape with their circumferential centers protruding toward the inner periphery 13.

[0134] Two permanent magnets 21, 22 are arranged in one magnet insertion hole 101. The permanent magnets 21, 22 arranged in the magnet insertion hole 101 form one magnetic pole. The number of poles p of the rotor 1F is the same as the number h of the magnet insertion holes 101, for example, six.

[0135] The rotor core 10 of the rotor 1F has gaps A1 to Am and gaps B1 to Bn in the radial region between the inner periphery 13 and the magnet insertion holes 101. The gaps A1 to Am and gaps B1 to Bm are as described in each embodiment.

[0136] In rotor 1F of variant 1, gaps A1 to Am and gaps B1 to Bn are also provided in rotor core 10, and W1 > W2 and R2 ≦ 1.15 × R1 are satisfied. This allows heat transfer from inner periphery 13 to outer periphery 14 to be more uniform on first side S1 and second side S2, thereby making the temperature distribution in rotor core 10 uniform.

[0137] Figure 17(B) is a cross-sectional view showing a rotor 1G of Modification 2. The rotor core 10 of the rotor 1G shown in Figure 17(B) has k pairs of magnet insertion holes 111, 112 (k is an integer of 2 or greater). Here, k is 6, but it may be any number greater than or equal to 2.

[0138] The magnet insertion holes 111 and 112 are arranged in a V-shape such that the opposing sides protrude toward the inner circumference 13. A permanent magnet 21 is arranged in the magnet insertion hole 111, and a permanent magnet 22 is arranged in the magnet insertion hole 112.

[0139] The permanent magnets 21, 22 arranged in one set of magnet insertion holes 111, 112 constitute one magnetic pole. The distance H1 between the magnet insertion holes 111, 112 of adjacent magnetic poles is wider than the distance H2 between the magnet insertion holes 111, 112 of one magnetic pole. The number of poles p of the rotor 1G is the same as the number of sets k of the magnet insertion holes 111, 112, e.g., six.

[0140] The rotor core 10 of the rotor 1G has gaps A1 to Am and gaps B1 to Bn in the radial region between the inner periphery 13 and the magnet insertion holes 101. The gaps A1 to Am and gaps B1 to Bm are as described in each embodiment.

[0141] In rotor 1G of modified example 2, gaps A1 to Am and gaps B1 to Bm are also provided in rotor core 10, and W1 > W2 and R2 ≦ 1.15 × R1 are satisfied. This makes it possible to more evenly distribute heat between first side S1 and second side S2 from inner periphery 13 to outer periphery 14, thereby making the temperature distribution in rotor core 10 uniform.

[0142] In the above-described first to fourth embodiments and modifications 1 and 2, the voids A1 to Am are formed on the first side S1, and the voids B1 to Bm are formed on the second side S2. However, as shown in FIG. 18A , at least one void A (e.g., void A1 or A4) among the voids A1 to Am may extend onto the second side S2. In other words, it is sufficient that a portion occupying half or more of the total area of ​​the voids A1 to Am is located on the first side S1.

[0143] 18B, at least one void B (e.g., void B1 or B4) among the voids B1 to Bn may extend onto the first side S1. In other words, it is sufficient that a portion occupying half or more of the total area of ​​the voids B1 to Bn is located on the second side S2.

[0144] <Compressor> Next, a compressor 300 to which the motor 5 of any of the first to fourth embodiments can be applied will be described. Fig. 19 is a vertical cross-sectional view showing the compressor 300 equipped with the motor 5 of the first embodiment. The compressor 300 is a rotary compressor in this example, but may also be a scroll compressor.

[0145] The compressor 300 includes a sealed container 307, a compression mechanism 301 disposed in the sealed container 307, and a motor 5 that drives the compression mechanism 301. The configuration of the motor 5 is as described in the first embodiment.

[0146] The compression mechanism 301 has a cylinder 302 having a cylinder chamber 303, a rolling piston 304 fixed to the shaft 25 of the motor 5, 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 25 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.

[0147] 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 25 is rotatably held by an upper frame 305 and a lower frame 306 that serve as bearings.

[0148] The cylinder 302 has a cylinder chamber 303 therein, and the rolling piston 304 rotates eccentrically within the cylinder chamber 303. The shaft 25 has an eccentric shaft portion, and the rolling piston 304 is fitted onto the eccentric shaft portion.

[0149] The stator 3 of the motor 5 is assembled inside the sealed container 307 by shrink fitting, press fitting, welding, or other methods. The shell 28 shown in FIG. 1 corresponds to a part of the sealed container 307. Electric power is supplied to the coil 35 of the stator 3 from a glass terminal 311 fixed to the sealed container 307. The shaft 25 is fixed to the rotor core 10 as described above.

[0150] 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.

[0151] 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.

[0152] The eccentricity of the rotor 1 described in the first embodiment and the like is adjusted so that the rotation of the rotor 1 is stable, taking into consideration various factors such as the eccentricity of the rolling piston 304 in the compression mechanism 301.

[0153] 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:

[0154] (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.

[0155] 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 motor 5 is driven by supplying current to the coil 35, the shaft 25 rotates together with the rotor 1. Then, the rolling piston 304 fitted to the shaft 25 rotates eccentrically within the cylinder chamber 303, compressing the refrigerant within the cylinder chamber 303.

[0156] The refrigerant compressed in the cylinder chamber 303 passes through discharge mufflers 308 and 309, and then passes through the groove 30c of the stator 3 (FIG. 1) and the air gap between the rotor 1 and the refrigerant, 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.

[0157] Since this compressor 300 has the motor 5 described in the first embodiment, vibration and noise can be suppressed by suppressing uneven thermal expansion of the rotor core 10. This improves the quietness and reliability of the compressor 300. The motor is not limited to the motor described in the first embodiment, and a motor having a rotor described in any of the second to fourth embodiments or the first and second modifications may also be used.

[0158] <Refrigeration cycle device> Next, a refrigeration cycle device 400 having the compressor 300 shown in Fig. 19 will be described. Fig. 20 is a diagram showing the refrigeration cycle device 400. The refrigeration cycle device 400 is, for example, an air conditioner, but is not limited to this and may be, for example, a refrigerator.

[0159] 20 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.

[0160] 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 formed by the compressor 300 shown in Fig. 19. The refrigeration cycle device 400 also includes an outdoor fan 405 facing the condenser 402 and an indoor fan 406 facing the evaporator 404.

[0161] 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.

[0162] 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.

[0163] The compressor 401 of the refrigeration cycle apparatus 400 has the motor 5 of the first embodiment, and is therefore quieter and more reliable. This improves the quietness and reliability of the refrigeration cycle apparatus 400. The compressor 401 is not limited to the motor described in the first embodiment, and may be a motor having a rotor described in any of the second to fourth embodiments or the modified examples.

[0164] 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.

[0165] DESCRIPTION OF SYMBOLS 1, 1A, 1B, 1C, 1D, 1E, 1F, 1G Rotor, 3 Stator, 5 Motor, 10 Rotor core, 11 Magnet insertion hole, 13 Inner circumference, 14 Outer circumference, 15 Rib (first rib), 16 Rib (second rib), 20 Permanent magnet, 25 Shaft, 30 Stator core, 31 Yoke, 32 Teeth, 33 Slot, 34 Insulating portion, 35 Coil, 51 Inner circumference edge, 52 Outer circumference edge, 53, 53a, 53b Side edge, 61 Inner circumference edge, 62 Outer circumference edge, 63 Side edge, 81 First core portion, 82 Second core portion, 300 Compressor, 301 Compression mechanism, 302 Cylinder, 307 Sealed container, 400 refrigeration cycle device, 401 compressor, 402 condenser, 403 pressure reducing device, 404 evaporator, A, A1 to A6 gaps (first gaps), B, B1 to B6 gaps (second gaps), S1 first side, S2 second side, Q reference point, T reference plane.

Claims

1. An annular rotor core extending in the circumferential direction around a rotation axis, comprising a rotor core having a magnet insertion hole, A permanent magnet placed in the aforementioned magnet insertion hole and It has, The rotor core has m (where m is an integer of 1 or more) first voids and n (where n is an integer of 1 or more) second voids in the region between the inner circumference of the rotor core and the magnet insertion hole in the radial direction centered on the rotation axis. The m first voids and the n second voids are formed along the inner circumference of the rotor core. If we define one side as the first side and the other side as the second side with respect to the reference plane including the axis of rotation, In a plane perpendicular to the axis of rotation, the portion occupying more than half of the total area of ​​the m first voids is located on the first side, and the portion occupying more than half of the total area of ​​the n second voids is located on the second side. The radial width W1 of at least one of the m first voids and the radial width W2 of at least one of the n second voids satisfy W1 > W2. The shortest distance R1 from the rotation axis to the m first gaps and the shortest distance R2 from the rotation axis to the n second gaps satisfy R2 ≤ 1.15 × R1. Rotor.

2. The shortest distance R1 from the rotation axis to the m first gaps and the shortest distance R2 from the rotation axis to the n second gaps satisfy R2 < R1. The rotor according to claim 1.

3. The shortest distance R1 from the rotation axis to the m first gaps and the shortest distance R2 from the rotation axis to the n second gaps satisfy 0.95 × R1 ≤ R2 < R1. The rotor according to claim 2.

4. The aforementioned m first voids are, A first void is formed asymmetrically with respect to a straight line passing through the rotation axis that bisects the void area on a plane perpendicular to the rotation axis. including The rotor according to any one of claims 1 to 3.

5. Among the m (an integer of 2 or more) first voids, a first rib is formed between two adjacent first voids. The circumferential width of the first rib is wider at the radially outer end than at the radially inner end of the first rib. The rotor according to any one of claims 1 to 3.

6. Of the n second voids, the circumferential length of at least one second void is longer than the circumferential length of the other second voids. The rotor according to any one of claims 1 to 3.

7. The at least one second void is the central void among the n second voids. The rotor according to claim 6.

8. The rotor core has a first core portion and a second core portion in the axial direction of the rotation shaft. The first void in the first core portion and the second void in the second core portion are continuous in the axial direction. The second void in the first core portion and the first void in the second core portion are continuous in the axial direction. The rotor according to any one of claims 1 to 3.

9. The aforementioned magnet insertion hole is one of h magnet insertion holes (where h is an integer of 2 or more) formed at equal intervals in the circumferential direction in the rotor core. The electromagnetic steel sheet constituting the second core portion is positioned at a location rotated by an integer multiple of 360 degrees per hour around the rotation axis relative to the electromagnetic steel sheet constituting the first core portion. The rotor according to claim 8.

10. If the number of poles of the rotor is p (where p is an integer greater than or equal to 2), then m ≥ p / 2 holds true. The rotor according to any one of claims 1 to 3.

11. If the number of poles of the rotor is p (where p is an integer greater than or equal to 2), then n ≥ p / 2 holds true. The rotor according to any one of claims 1 to 3.

12. A rotor according to any one of claims 1 to 3, The stator surrounding the rotor and Equipped with Motor.

13. The motor according to claim 12, The compression mechanism driven by the motor and A compressor equipped with a compressor.

14. A compressor according to claim 13, a condenser, a pressure reducing device, and an evaporator are included. Refrigeration cycle device.

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