Rotors, electric motors, blowers, and refrigeration systems

Abstract

The present invention provides an electric motor rotor, electric motor, blower, and refrigeration system that can accommodate larger magnets. [Solution] The rotor 40 of the external-rotor electric motor 20 comprises a rotor magnetic core 50 and magnets 60 embedded in the rotor magnetic core 50 at predetermined intervals in the circumferential direction of the rotor 40. The magnets 60 include a first magnet 70. The first magnet 70 is arranged such that the angle between the average magnetization direction AM of the first magnet 70 and the radial direction of the rotor 40 is greater than 0° and less than 90°. The first magnet 70 has a first magnetic pole surface and a second magnetic pole surface located radially inward from the first magnetic pole surface. The radially outward end of the first magnetic pole surface is located radially outward from the average outer circumference position of the rotor magnetic core 50.

Description

Technical Field

[0001] The present disclosure relates to a rotor for an outer-rotor type electric motor, an electric motor, a blower, and a refrigeration apparatus.

Background Art

[0002] Motors in which magnets are embedded in the rotor are known. Patent Document 1 discloses an inner-rotor type motor in which flux barriers are provided at both ends of the magnets embedded in the motor.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problem to be Solved by the Invention

[0004] By the way, mounting larger magnets on the rotor can be expected to improve the torque performance of the motor. However, when flux barriers are provided at both ends of the magnet to prevent magnetic flux short-circuiting at the ends of the magnet, the size of the magnet is limited because the magnet cannot be placed in the flux barrier portion.

Means for Solving the Problem

[0005] A rotor according to a first aspect for solving the above problem is a rotor of an outer-rotor type electric motor, comprising: a rotor core; and magnets embedded in the rotor core at predetermined intervals in the circumferential direction of the rotor. The magnets include a first magnet, the first magnet is arranged such that an angle formed between the average magnetization direction of the first magnet and the radial direction of the rotor is greater than 0° and less than 90°, the first magnet has a first magnetic pole surface and a second magnetic pole surface located radially inward of the first magnetic pole surface, and an end portion of the first magnetic pole surface on the radially outer side is located radially outward of the average outer peripheral position of the rotor core.

[0006] With the above configuration, the size of the first magnet can be increased by positioning the radially outer end of the first magnet radially further outward than the average outer circumference position of the rotor core. Therefore, in an out-rotating type motor of the same size, a larger magnet can be mounted on the rotor core than in a motor where flux barriers are provided at both ends of the magnet.

[0007] In the rotor of the second view, the second outer end located radially outward of the second pole surface is located radially inward from the average outer circumference position of the rotor magnetic core.

[0008] With the above configuration, most of the first and second pole surfaces of the magnet can be placed inside the rotor core, thus reducing the magnetic resistance between the first and second pole surfaces. This improves the magnetic flux density of the magnet.

[0009] In the third aspect, the rotor, in the first or second aspect, has a retaining portion that covers the radially outer end of the second pole surface.

[0010] With the above configuration, the retaining part can prevent the first magnet from coming out of the rotor magnetocore.

[0011] The rotor in the fourth view is such that, in any one of the rotors in the first to third views, the magnets include a second magnet that is circumferentially adjacent to the first magnet when the rotor is viewed from the axial direction, and the first magnet overlaps the second magnet radially.

[0012] With the above configuration, the first magnet and the second magnet overlap in the radial direction, so even when a large magnet is placed in the rotor core, the size of the rotor in the radial direction can be reduced.

[0013] In the fifth aspect of the rotor, in any one of the first to fourth aspects of the rotor, the length of the straight line connecting each end of the first pole surface of the first magnet is longer than the length obtained by dividing the length of the inner circumference of the rotor core by the number of poles of the rotor.

[0014] According to the above configuration, by tilting the first magnet with respect to the radial direction, a portion of the first magnet is positioned radially outward with respect to the rotor core.

[0015] The rotor of the sixth aspect further comprises a protective member in any one of the rotors of the first to fifth aspects, the protective member being arranged around the rotor core and the first magnet so as to cover the rotor core and the first magnet.

[0016] With the above configuration, the rotor magnetic core and the first magnet can be protected by the protective member.

[0017] In the rotor of the seventh aspect, in any one of the rotors of the first to sixth aspects, a flux barrier is provided in the portion of the rotor magnetic core radially inward from the magnet arrangement portion where the magnets are arranged, and the flux barrier is surrounded by the rotor magnetic core and the first magnet.

[0018] With the above configuration, the flux barrier can suppress short circuits of the magnetic flux.

[0019] In the rotor of the eighth aspect, in any one of the rotors of the first to sixth aspects, a flux barrier is provided in the portion of the rotor magnetic core radially inward from the magnet arrangement portion where the magnets are arranged, and the flux barrier opens radially inward.

[0020] With the above configuration, by reducing the internal leakage flux, it is possible to achieve a higher power density than an externally rotating motor of the same size.

[0021] The rotor according to the ninth aspect is the rotor according to the eighth aspect, wherein the magnet includes a second magnet circumferentially adjacent to the first magnet when the rotor is viewed in the axial direction, the second magnet has a third magnetic pole surface that is a surface located radially outward when the rotor is viewed in the axial direction, a radially outer end of the first magnetic pole surface is defined as a first outer end, a radially outer end of the second magnetic pole surface is defined as a second outer end, a radially outer end of the third magnetic pole surface is defined as a third outer end, and a portion of the rotor core located between the first outer end and the third outer end is defined as a second outer rotor core, the rotor core is constituted by split core portions arranged spaced apart from each other in the circumferential direction, the split core portions include the second outer rotor core, and the first magnet is in contact with an outer periphery of the second outer rotor core between the first outer end and the second outer end.

[0022] According to the above configuration, by further reducing the outer leakage magnetic flux, a higher output density can be achieved than that of an outer-rotor electric motor of the same size.

[0023] The rotor according to the tenth aspect is the rotor according to the eighth aspect, wherein a thickness of a portion of the rotor core (50) that is located radially inward of the magnet (60) is 0.5 mm or more.

[0024] According to the above configuration, sufficient strength can be maintained on the radially inner side of the rotor core.

[0025] The rotor according to the eleventh aspect is the rotor according to the eighth aspect, wherein the rotor core is constituted by core portions connected to each other on the radially outer side of the first magnet, and the core portions have bendable portions that can be bent so that the rotor core has an annular shape.

[0026] According to the above configuration, since the rotor core can be constituted by straight cores, manufacturing efficiency is good.

[0027] An electric motor according to the twelfth aspect includes the rotor according to any one of the first to eleventh aspects, and a stator disposed on an inner peripheral side of the rotor.

[0028] With the above configuration, the motor's torque performance can be improved by the rotor described above.

[0029] The blower according to the 13th view comprises an electric motor according to the 12th view and a fan section driven by the electric motor.

[0030] With the above configuration, the blower can effectively blow air using an electric motor with improved torque performance.

[0031] The refrigeration system of the 14th aspect is equipped with the electric motor of the 12th aspect.

[0032] With the above configuration, energy utilization efficiency can be improved by using an electric motor with improved torque performance. [Brief explanation of the drawing]

[0033] [Figure 1] Figure 1 is a schematic diagram of the indoor unit for a refrigeration system according to the first embodiment. [Figure 2] Figure 2 is a cross-sectional view showing a portion of the electric motor of the indoor unit shown in Figure 1. [Figure 3] Figure 3 is a cross-sectional view showing a portion of the rotor magnetic core of the electric motor rotor shown in Figure 2. [Figure 4] Figure 4 is a cross-sectional view showing a portion of the rotor of the electric motor shown in Figure 2. [Figure 5] Figure 5 is a cross-sectional view showing a portion of the electric motor according to the second embodiment. [Figure 6] Figure 6 is a cross-sectional view showing a portion of the rotor magnetic core of the electric motor rotor shown in Figure 5. [Figure 7] Figure 7 is a cross-sectional view showing a portion of the rotor of the electric motor according to the third embodiment. [Figure 8] Figure 8 is a cross-sectional view showing a portion of the rotor magnetic core of the rotor shown in Figure 7. [Figure 9] Figure 9 is an enlarged view of the cross-section of the bendable portion of the rotor magnetic core shown in Figure 8. [Figure 10]Figure 10 is a cross-sectional view showing a portion of the rotor magnetic core in a ring-shaped folded state. [Figure 11] Figure 11 is a cross-sectional view showing a portion of the modified rotor. [Figure 12] Figure 12 is a cross-sectional view showing a portion of the modified rotor. [Figure 13] Figure 13 is a cross-sectional view showing a portion of the modified rotor. [Figure 14] Figure 14 is a cross-sectional view showing a portion of the rotor with a modified protective member. [Figure 15] Figure 15 is a cross-sectional view showing a portion of the modified rotor. [Figure 16] Figure 16 is a cross-sectional view showing a portion of the modified rotor. [Figure 17] Figure 17 is a cross-sectional view showing a portion of the modified rotor. [Modes for carrying out the invention]

[0034] <First Embodiment> Referring to Figures 1 to 4, the rotor, motor, blower, and refrigeration system of the first embodiment will be described. In this embodiment, the motor is a motor.

[0035] The refrigeration system includes an electric motor 20. Examples of refrigeration systems include an air conditioner, a water heater, a chiller unit, and a cooling device for cooling the air inside the storage area. The air conditioner is either a refrigeration-only unit, a heating-only unit, or a heating and cooling unit that can switch between cooling and heating. The air inside the storage area is the air inside refrigerators, freezers, display cases, and containers. In this embodiment, the refrigeration system will be described as an air conditioner.

[0036] Figure 1 shows the indoor unit 1 of an air conditioner. In this embodiment, the electric motor 20 is provided in the indoor unit 1. The indoor unit 1 is, for example, a wall-mounted type that is attached to the wall of a room. The indoor unit 1 is connected to the outdoor unit of the air conditioner by refrigerant piping.

[0037] The indoor unit 1 includes a heat exchanger that exchanges heat with the air drawn in from the intake port, a blower 10, and a casing 2 that supports the heat exchanger and the blower 10. The heat exchanger and the blower 10 are arranged in the internal space of the casing 2.

[0038] The blower 10 comprises an electric motor 20 and a fan unit 11 driven by the electric motor 20. The fan unit 11 is located downstream of the heat exchanger in the airflow path from the intake port to the outlet port of the indoor unit 1. The fan unit 11 is a propeller fan, a centrifugal fan, or a cross-flow fan. Examples of centrifugal fans include turbo fans and sirocco fans. In this embodiment, the fan unit 11 is a cross-flow fan.

[0039] <Electric motor> The electric motor 20 is equipped with a rotating shaft 21. The direction in which the rotating shaft 21 of the electric motor 20 extends is defined as the axial direction. The direction perpendicular to the tangent to the rotating shaft 21 and extending outward from the tangent is defined as the radial direction. The direction around the circumference of the rotating shaft 21 is defined as the circumferential direction. For convenience of explanation, these may be referred to as the radial direction and the circumferential direction of the rotor 40.

[0040] Figure 2 shows a cross-section of a portion of the electric motor 20 in a direction perpendicular to the axial direction. The electric motor 20 is formed in a cylindrical shape. The electric motor 20 in this embodiment is of the external rotation type.

[0041] The electric motor 20 comprises a rotor 40 and a stator 30. The stator 30 is positioned on the inner circumference 40A side of the rotor 40. The rotating shaft 21 rotates integrally with the rotor 40. The stator 30 has a through hole 30A in which the rotating shaft 21 is positioned. The rotating shaft 21 is supported, for example, by a bearing provided in the through hole 30A. The bearing supports the rotating shaft 21 so that it rotates relative to the stator 30.

[0042] <Stata> The stator 30 has a stator core 31 and a coil 32. The stator core 31 is formed by laminating electromagnetic steel sheets. The electromagnetic steel sheets are soft magnetic materials. The stator core 31 has a plurality of teeth 33. The coil 32 is formed by winding a wire around the teeth 33 of the stator core 31. The wire is copper or aluminum. The wire is covered with an insulating material such as enamel resin.

[0043] An insulator is provided between the stator core 31 and the coil 32. The insulator is made of an insulating resin material. The insulator insulates the stator core 31 and the coil 32 so that the current flowing through the coil 32 is not transmitted to the stator core 31.

[0044] <Rotor> The rotor 40 comprises a rotor magnetic core 50 and a magnet 60. The rotor magnetic core 50 includes electrical steel sheets, SPCC (Steel Plate Cold Commercial), or a powdered magnetic core. The rotor magnetic core 50 is formed by laminating electrical steel sheets, laminating SPCC, or by a powdered magnetic core.

[0045] As shown in Figure 3, the rotor core 50 includes a magnet arrangement section 51 where the magnets 60 are placed. The magnet arrangement section 51 opens radially outward. A flux barrier 52 is provided in the portion of the rotor core 50 radially inward from the magnet arrangement section 51. The flux barrier 52 is, for example, an air gap that separates a magnetic path with high magnetic resistance from a magnetic path with low magnetic resistance. No magnets 60 are placed in the flux barrier 52. In Figure 3, the boundary between the magnet arrangement section 51 and the flux barrier 52 is shown by a dashed line. In one example, the flux barrier 52 is surrounded by the rotor core 50 and the first magnet 70. The portion of the rotor core 50 that faces the flux barrier 52 and is radially inward from the flux barrier 52 is defined as the inner connection section 50A. In this embodiment, the rotor core 50 is connected by the inner connection section 50A.

[0046] The rotor core 50 has a retaining portion 53. The retaining portion 53 prevents the magnet 60 from coming out radially outward due to centrifugal force. The retaining portion 53 is provided on the part of the rotor core 50 adjacent to the magnet arrangement portion 51. The retaining portion 53 covers the second outer end 72A of the second pole surface 72. The second pole surface 72 and the second outer end 72A will be described later.

[0047] The magnets 60 are embedded in the rotor core 50 at predetermined intervals in the circumferential direction of the rotor 40. The magnets 60 are permanent magnets. The magnets 60 are ceramic magnets, metal magnets, or bonded magnets. The magnets 60 are anisotropic or isotropic magnets. The shape of the magnets 60 in a cross-section perpendicular to the axial direction is, for example, plate-like. The shape of the magnets 60 in a cross-section perpendicular to the axial direction may also be a chamfered shape, trapezoidal, crescent-shaped, semi-circular, or arc-shaped.

[0048] The magnet 60 has magnetic pole surfaces 61. In a cross-section perpendicular to the axial direction, as shown in Figure 2, the magnet 60 has two magnetic pole surfaces 61. The magnetic pole surfaces 61 include the surfaces of the magnet 60 from which magnetic force is emitted, and the surfaces from which magnetic force is absorbed. Of the surfaces of the magnet 60, the surface from which magnetic force is emitted is called the discharge surface 61A. Magnetic force is emitted perpendicularly from the discharge surface 61A. Of the surfaces of the magnet 60, the surface from which magnetic force is absorbed is called the absorption surface 61B. Magnetic force enters perpendicularly to the absorption surface 61B.

[0049] The magnets 60 are inserted into the magnet arrangement portion 51 of the rotor core 50 from the axial direction. As shown in Figure 2, each of the circumferentially adjacent magnets 60 is arranged on the rotor core 50 such that the magnetic pole surfaces 61, which are located radially outward, alternate between discharge surfaces 61A and suction surfaces 61B.

[0050] The magnet 60 includes the first magnet 70. One of the magnets 60 provided on the rotor 40 is selected as the first magnet 70. The first magnet 70 is positioned such that the angle between the mean magnetization direction AM of the first magnet 70 and the radial direction of the motor 20 is greater than 0° and less than 90°. The angle between the mean magnetization direction AM of the first magnet 70 and the radial direction of the motor 20 is equal to the angle between the straight line along the mean magnetization direction AM of the first magnet 70 and the straight line along the radial direction of the motor 20. The magnetization direction is the direction of the magnetic flux lines of the magnetic flux flowing inside the magnet 60. The mean magnetization direction AM is the direction obtained by averaging the magnetization directions across the magnetic pole surface 61.

[0051] As shown in Figure 4, the first magnet 70 has a first pole surface 71. The first pole surface 71 is the surface located radially outward from the second pole surface 72 when the rotor 40 is viewed from the axial direction. When the discharge surface 61A of the first magnet 70 is located radially outward, the first pole surface 71 corresponds to the discharge surface 61A of the first magnet 70. When the suction surface 61B of the first magnet 70 is located radially outward, the first pole surface 71 corresponds to the suction surface 61B of the first magnet 70.

[0052] The first magnet 70 has a second pole surface 72. The second pole surface 72 is a surface located radially inward from the first pole surface 71 when the rotor 40 is viewed from the axial direction. When the discharge surface 61A of the first magnet 70 is located radially inward, the second pole surface 72 corresponds to the discharge surface 61A of the first magnet 70. When the suction surface 61B of the first magnet 70 is located radially inward, the second pole surface 72 corresponds to the suction surface 61B of the first magnet 70.

[0053] The ends of the first pole surface 71 are portions that neither emit nor absorb magnetic force. Of the ends of the first pole surface 71, the end located radially outward when the rotor 40 is viewed from the axial direction is designated as the first outer end 71A. Of the ends of the first pole surface 71, the end located radially inward when the rotor 40 is viewed from the axial direction is designated as the first inner end 71B.

[0054] The ends of the second pole surface 72 are portions that neither emit nor absorb magnetic force. Of the ends of the second pole surface 72, the end located radially outward when the rotor 40 is viewed from the axial direction is designated as the second outer end 72A. Of the ends of the second pole surface 72, the end located radially inward when the rotor 40 is viewed from the axial direction is designated as the second inner end 72B.

[0055] The first outer end 71A of the first pole surface 71 is located radially outward from the average outer circumference position AP of the rotor core 50. The first outer end 71A protrudes from the outer circumference 54A of the rotor core 50. The first inner end 71B of the first pole surface 71 is located radially inward from the average outer circumference position AP of the rotor core 50.

[0056] The second outer end 72A of the second pole surface 72 is located radially inward from the average outer circumference position AP of the rotor core 50. The second inner end 72B of the second pole surface 72 is located radially inward from the average outer circumference position AP of the rotor core 50.

[0057] The length of the straight line connecting the first outer end 71A and the first inner end 71B of the first pole surface 71 is longer than the length of the inner circumference 40A of the rotor core 50 divided by the number of poles of the rotor 40. The length of the straight line connecting the second outer end 72A and the first inner end 71B of the second pole surface 72 of the first magnet 70 is longer than the length of the inner circumference 40A of the rotor core 50 divided by the number of poles of the rotor 40.

[0058] The magnet 60 includes a second magnet 80 that is circumferentially adjacent to the first magnet 70 when the rotor 40 is viewed from the axial direction. The rotor 40 rotates in a first rotational direction R1 or a second rotational direction R2 opposite to the first rotational direction R1. The second magnet 80 is a magnet 60 that is adjacent to the magnet 60 designated as the first magnet 70 in the first rotational direction R1 when the rotor 40 is viewed from the axial direction.

[0059] The second magnet 80 is positioned such that the angle between the mean magnetization direction AM of the second magnet 80 and the radial direction of the motor 20 is greater than 0° and less than 90°. The angle between the mean magnetization direction AM of the second magnet 80 and the radial direction of the motor 20 is equal to the angle between the line along the mean magnetization direction AM of the second magnet 80 and the line along the radial direction of the motor 20. The second magnet 80 may also be positioned such that the angle between the mean magnetization direction AM of the second magnet 80 and the radial direction of the motor 20 is equal to 0°. The second magnet 80 may also be positioned such that the angle between the mean magnetization direction AM of the second magnet 80 and the radial direction of the motor 20 is 90° or greater.

[0060] The second magnet 80 has a third pole surface 81. The third pole surface 81 is the surface located radially outward when the rotor 40 is viewed from the axial direction. When the discharge surface 61A of the second magnet 80 is located radially outward, the third pole surface 81 corresponds to the discharge surface 61A of the second magnet 80. When the suction surface 61B of the second magnet 80 is located radially outward, the third pole surface 81 corresponds to the suction surface 61B of the second magnet 80. The ends of the third pole surface 81 are portions that neither discharge nor draw in magnetic force. Of the ends of the third pole surface 81, the end located radially outward when the rotor 40 is viewed from the axial direction is called the third outer end 81A.

[0061] The first magnet 70 overlaps the second magnet 80 in the radial direction. The portion of the first magnet 70 that overlaps the second magnet 80 in the radial direction is positioned with a radial gap between it and the second magnet 80.

[0062] The magnet 60 includes a third magnet 90 that is adjacent to the first magnet 70 in the circumferential direction when the rotor 40 is viewed from the axial direction. The third magnet 90 is a magnet 60 that is adjacent to the magnet 60 designated as the first magnet 70 in the second rotational direction R2 when the rotor 40 is viewed from the axial direction.

[0063] The third magnet 90 is positioned such that the angle between the mean magnetization direction AM of the third magnet 90 and the radial direction of the motor 20 is greater than 0° and less than 90°. The angle between the mean magnetization direction AM of the third magnet 90 and the radial direction of the motor 20 is equal to the angle between the line along the mean magnetization direction AM of the third magnet 90 and the line along the radial direction of the motor 20. The third magnet 90 may also be positioned such that the angle between the mean magnetization direction AM of the third magnet 90 and the radial direction of the motor 20 is equal to 0°. The third magnet 90 may also be positioned such that the angle between the mean magnetization direction AM of the third magnet 90 and the radial direction of the motor 20 is 90° or greater.

[0064] The third magnet 90 has a fourth pole surface 91. The fourth pole surface 91 is the surface located radially outward when the rotor 40 is viewed from the axial direction. When the discharge surface 61A of the third magnet 90 is located radially outward, the fourth pole surface 91 corresponds to the discharge surface 61A of the third magnet 90. When the suction surface 61B of the third magnet 90 is located radially outward, the fourth pole surface 91 corresponds to the suction surface 61B of the second magnet 80.

[0065] The ends of the fourth pole surface 91 are portions that neither emit nor absorb magnetic force. Of the ends of the fourth pole surface 91, the end located radially outward when the rotor 40 is viewed from the axial direction is designated as the fourth outer end 91A.

[0066] The third magnet 90 overlaps the first magnet 70 in the radial direction. The portion of the third magnet 90 that overlaps the first magnet 70 in the radial direction is positioned with a radial gap between it and the first magnet 70.

[0067] The portion of the rotor magnetic core 50 located between the first outer end 71A of the first pole surface 71 and the fourth outer end 91A of the fourth pole surface 91 is defined as the first outer rotor magnetic core 54. The first outer rotor magnetic core 54 is, for example, the portion of the rotor magnetic core 50 that covers the first pole surface 71 of the first magnet 70 and is located radially outward from the first pole surface 71. The first outer rotor magnetic core 54 is, for example, the portion located in the circumferential direction between a straight line connecting the first outer end 71A and the rotation axis of the rotor 40 and a straight line connecting the fourth outer end 91A and the rotation axis of the rotor 40.

[0068] The position of a predetermined point on the outer circumference 54A of the first outer rotor core 54 is defined as the outer circumference position. Multiple points are plotted on the outer circumference 54A of the first outer rotor core 54. The average outer circumference position AP is represented by the average value of the lengths of multiple straight lines connecting each of the multiple points plotted at predetermined intervals on the outer circumference 54A of the first outer rotor core 54 to the rotation axis of the rotor 40.

[0069] The portion of the rotor core 50 located between the first outer end 71A of the first pole surface 71 and the third outer end 81A of the third pole surface 81 is defined as the second outer rotor core 55. The second outer rotor core 55 is, for example, the portion of the rotor core 50 that covers the third pole surface 81 of the second magnet 80 and is located radially outward from the third pole surface 81. The second outer rotor core 55 is, for example, the portion located in the circumferential direction between a straight line connecting the first outer end 71A and the rotation axis of the rotor 40 and a straight line connecting the third outer end 81A and the rotation axis of the rotor 40.

[0070] The point where the first magnet 70 and the second outer rotor magnetic core 55 come into contact is defined as the first contact point P1. The length of the straight line connecting the first outer end 71A and the rotation axis of the rotor 40 is longer than the length of the straight line connecting the first contact point P1 and the rotation axis of the rotor 40.

[0071] <Performance Comparison Test> The performance comparison test is a test to compare the performance of the motor 20 of the first embodiment with the performance of a comparison motor. The performance comparison test is performed, for example, by comparing the average output torque when the motor 20 and the comparison motor are driven for a predetermined period of time.

[0072] The comparative motor is configured similarly to the motor 20, except that the configuration of the radially outer end of the first pole surface 71 is different. In the motor 20 of the first embodiment, the first outer end 71A is located radially outward from the average outer circumference position AP of the rotor core 50. In contrast, in the comparative motor, the radially outer end of the first pole surface 71 is located radially inward from the average outer circumference position AP of the rotor core 50.

[0073] The results of the performance comparison test showed that the average output torque of the electric motor 20 was 20% higher than the average output torque of the comparison electric motor. From this result, it became clear that the performance of the electric motor 20 is improved by arranging the magnets 60 as in the first embodiment.

[0074] <Effects of the First Embodiment> The effects of the first embodiment will be explained. (1-1) The rotor 40 is the rotor 40 of an external motor 20 and comprises a rotor magnetic core 50 and magnets 60 embedded in the rotor magnetic core 50 at predetermined intervals in the circumferential direction of the rotor 40. The magnets 60 include a first magnet 70. The first magnet 70 is arranged such that the angle between the average magnetization direction AM of the first magnet 70 and the radial direction of the rotor 40 is greater than 0° and less than 90°. The first magnet 70 has a first pole surface 71 and a second pole surface 72 located radially inward from the first pole surface 71. The radially outward end of the first pole surface 71 is located radially outward from the average outer circumference position AP of the rotor magnetic core 50.

[0075] According to the above configuration, the size of the first magnet 70 can be increased by positioning the radially outer end of the first magnet 70 radially outward from the average outer circumference position AP of the rotor magnetic core 50. Therefore, in an out-rotating type motor 20 of the same size, a larger magnet 60 can be mounted on the rotor magnetic core 50 than in a motor 20 in which flux barriers 52 are provided at both ends of the magnet 60.

[0076] Furthermore, with the above configuration, the radially outer end of the first magnet 70 is located radially outward from the average outer circumference position AP of the rotor core 50, making it difficult for a path for a magnetic flux short circuit to form.

[0077] (1-2) The second outer end portion 72A, located radially outward of the second pole surface 72, is located radially inward from the average outer circumference position AP of the rotor core 50.

[0078] With the above configuration, most of the first and second pole surfaces 71 and 72 of the magnet 60 can be placed inside the rotor core 50, thus reducing the magnetic resistance between the first and second pole surfaces 71 and 72. As a result, the magnetic flux density of the magnet 60 is improved.

[0079] (1-3) The rotor magnetic core 50 has a retaining portion 53. The retaining portion 53 covers the end on the radially outer side of the second magnetic pole surface 72.

[0080] With the above configuration, the retaining portion 53 can prevent the first magnet 70 from coming off the rotor core 50.

[0081] (1-4) When the rotor 40 is viewed from the axial direction, the magnet 60 includes a second magnet 80 that is circumferentially adjacent to the first magnet 70. The first magnet 70 overlaps the second magnet 80 in the radial direction.

[0082] With the above configuration, the first magnet 70 and the second magnet 80 overlap in the radial direction, so even when a large magnet 60 is placed on the rotor core 50, the size of the rotor 40 in the radial direction can be reduced.

[0083] (1-5) The length of the straight line connecting each end of the first pole surface 71 of the first magnet 70 is longer than the length obtained by dividing the length of the inner circumference 40A of the rotor core 50 by the number of poles of the rotor 40.

[0084] According to the above configuration, by tilting the first magnet 70 with respect to the radial direction, a portion of the first magnet 70 is positioned radially outward relative to the rotor core 50.

[0085] (1-6) The rotor 40 further comprises a protective member 41. The protective member 41 is positioned around the rotor magnetic core 50 and the first magnet 70 so as to cover the rotor magnetic core 50 and the first magnet 70.

[0086] According to the above configuration, the rotor magnetic core 50 and the first magnet 70 can be protected by the protective member 41.

[0087] (1-7) A flux barrier 52 is provided in the portion of the rotor magnetic core 50 radially inward from the magnet arrangement portion 51 where the magnets 60 are placed. The flux barrier 52 is surrounded by the rotor magnetic core 50 and the first magnet 70.

[0088] According to the above configuration, the flux barrier 52 can suppress short circuits of the magnetic flux.

[0089] (1-8) The electric motor 20 comprises a rotor 40 and a stator 30 positioned on the inner circumference 40A side of the rotor 40. With the above configuration, the electric motor 20 can improve its torque performance with the rotor 40.

[0090] (1-9) The blower 10 comprises an electric motor 20 and a fan section 11 driven by the electric motor 20. With the above configuration, the blower 10 can blow air effectively using the electric motor 20, which has improved torque performance.

[0091] (1-10) The refrigeration system is equipped with an electric motor 20. With the above configuration, the energy utilization efficiency can be improved by the electric motor 20 with improved torque performance.

[0092] <Second Embodiment> The rotor of this embodiment is configured based on the first embodiment. The following description shows the main differences between the rotor of this embodiment and the rotor of the first embodiment. Some or all of the descriptions of the components of the rotor of this embodiment that are common with the rotor of the first embodiment are omitted.

[0093] The rotor core 50 of this embodiment is composed of divided core sections 100 that are spaced apart from each other in the circumferential direction. The divided core sections 100 are composed of a plurality of core sheets stacked in the axial direction. The core sheets constituting the divided core sections 100 are formed, for example, from thin metal strips that have been pressed. The divided core sections 100 are arranged in the circumferential direction, for example, along an annular frame. Magnets 60 are placed between the divided core sections 100.

[0094] As shown in Figures 5 and 6, the flux barrier 52 in this embodiment opens radially inward. That is, the divided core portions 100 of the rotor core 50 in this embodiment are not connected at the inner connection portion 50A. Furthermore, the divided core portions 100 of the rotor core 50 are not connected to each other radially outward of the first magnet 70.

[0095] The divided core portion 100, positioned between the first magnet 70 and the second magnet 80, includes the second outer rotor core 55. The first magnet 70 contacts the outer circumference 55A of the second outer rotor core 55 between its first outer end 71A and second outer end 72A. In other words, the first contact point P1 is located between the first outer end 71A and the second outer end 72A of the first magnet 70. More specifically, the first magnet 70 contacts the outer circumference 55A of the second outer rotor core 55 between its first outer end 71A and second outer end 72A within a region circumferentially defined by its first outer end 71A and third outer end 81A.

[0096] The portion of the rotor magnetic core 50 that is radially inward from the magnet 60 is defined as the inner portion 50X. The thickness of the inner portion 50X is 0.5 mm or more. Specifically, the thickness of the thinnest part of the inner portion 50X is 0.5 mm or more.

[0097] <Effects of the second embodiment> The effects of the second embodiment will be explained. (2-1) A flux barrier 52 is provided in the portion of the rotor magnetic core 50 that is radially inward from the magnet arrangement portion 51 where the magnets 60 are placed. The flux barrier 52 opens radially inward.

[0098] With the above configuration, by reducing the internal leakage flux, it is possible to achieve a higher power density than an externally rotating motor of the same size.

[0099] (2-2) The rotor core 50 is composed of divided core portions 100 that are spaced apart from each other in the circumferential direction. The divided core portions 100 include a second outer rotor core 55. The first magnet 70 is in contact with the outer circumference 55A of the second outer rotor core 55 between its first outer end 71A and second outer end 72A.

[0100] With the above configuration, in addition to reducing the internal leakage flux, further reducing the external leakage flux makes it possible to achieve a higher power density than an externally rotating motor of the same size.

[0101] (2-3) The thickness of the inner portion 50X of the rotor magnetic core 50 is 0.5 mm or more. With the above configuration, sufficient strength can be maintained in the radially inner portion of the rotor magnetic core 50.

[0102] <Third Embodiment> The rotor of this embodiment is configured based on the first embodiment. The following description shows the main differences between the rotor of this embodiment and the rotor of the first embodiment. Some or all of the descriptions of the components of the rotor of this embodiment that are common with the rotor of the first embodiment are omitted.

[0103] As shown in Figures 7 to 10, the rotor core 50 of this embodiment is composed of core portions 110 connected to each other on the radially outer side of the first magnet 70. The core portions 110 are composed of a plurality of core sheets stacked in the axial direction. The core sheets constituting the core portions 110 are formed, for example, from thin metal strips that have been pressed.

[0104] The core portion 110 has a partial core portion 110A. The partial core portion 110A is connected by an outer connecting portion 50B, which is the portion of the rotor magnetic core 50 that is in contact with the magnet 60 and is radially outward from the magnet 60. The core portion 110 is, for example, a straight core in which the partial core portions 110A are connected in a substantially straight line. The core portion 110 may also be a core in which the partial core portions 110A are connected in a ring shape.

[0105] As shown in Figure 7, the flux barrier 52 of this embodiment opens radially inward. That is, the partial core portions 110A of the rotor core 50 of this embodiment are not connected to each other at the inner connection portions 50A. The thickness of the inner portion 50X of the core portion 110 of the rotor core 50, which is the part radially inward from the magnet 60, is 0.5 mm or more. Specifically, the thickness of the thinnest part of the inner portion 50X is 0.5 mm or more.

[0106] The core portion 110 has a bendable portion 111 that can be bent so that the rotor magnetic core 50 becomes an annular shape. As shown in Figures 8 and 9, the bendable portion 111 is provided on the radially outer portion of the rotor magnetic core 50 relative to the magnet 60. The bendable portion 111 is a part processed to make the rotor magnetic core 50 easily bendable. The bendable portion 111 is, for example, a notch. The base of the notch of the bendable portion 111 may be punched out in a substantially circular shape to facilitate bending.

[0107] The flexible portion 111 includes a first flexible portion 111A and a second flexible portion 111B. The first flexible portion 111A is provided in the portion of the outer connection portion 50B that corresponds to the first outer end 71A of the first magnetic pole surface 71 of the first magnet 70. The second flexible portion 111B is provided between the outer connection portion 50B and the second outer rotor magnetic core 55.

[0108] When the first flexible portion 111A is bent, a first corner portion 112 is formed where the first outer end portion 71A of the first pole surface 71 of the first magnet 70 is located. When the second flexible portion 111B is bent, a second corner portion 113 is formed where the second outer end portion 72A of the first pole surface 71 of the first magnet 70 is located.

[0109] Both ends of the core portion 110 are connected by welding or the like after the core portion 110, which is a straight core, is bent so that it forms an annular shape. The rotor magnetic core 50 may be formed by the core portion 110 divided in half, or by the core portion 110 divided into three or more parts. If the core portion 110 is divided into multiple parts, after the core portion 110 is bent, the ends of each core portion 110 are connected by welding or the like so that the rotor magnetic core 50 forms an annular shape.

[0110] The magnet placement section 51 is formed by bending the bendable section 111. The magnets 60 are placed in the magnet placement section 51, for example, after the magnet placement section 51 has been formed. Alternatively, the magnets 60 may be placed in advance in the area where the magnet placement section 51 is to be formed, and the core section 110 may be bent into an annular shape.

[0111] <Effects of the Third Embodiment> The effects of the third embodiment will be explained. (3-1) A flux barrier 52 is provided in the portion of the rotor magnetic core 50 that is radially inward from the magnet arrangement portion 51 where the magnets 60 are placed. The flux barrier 52 opens radially inward.

[0112] With the above configuration, by reducing the internal leakage flux, it is possible to achieve a higher power density than an externally rotating motor of the same size.

[0113] (3-2) The rotor magnetic core 50 is composed of core portions 110 that are connected to each other on the radially outer side of the first magnet 70. The core portions 110 have a bendable portion 111 that can be bent so that the rotor magnetic core 50 becomes an annular shape.

[0114] According to the above configuration, the rotor magnetic core 50 can be constructed using a straight core, resulting in good manufacturing efficiency.

[0115] <Example of changes> In addition to the embodiments described above, the rotor, motor, blower, and refrigeration system of this disclosure may also be, for example, modified versions shown below and combinations of at least two non-inconsistent modifications.

[0116] The first outer rotor magnetic core 54 may have a shape that covers the first magnetic pole surface 71.

[0117] As shown in Figure 11, the outer circumference 54A of the first outer rotor magnetic core 54 may have a shape that linearly connects the second contact point P2 and the first outer end 71A. The second contact point P2 is the point where the first outer rotor magnetic core 54 and the third magnet 90 come into contact.

[0118] As shown in Figure 12, the outer circumference 54A of the first outer rotor magnetic core 54 may have a shape that connects the second contact point P2 and the first outer end 71A of the above modified example in a curve different from a circular arc.

[0119] As shown in Figure 13, the first outer rotor core 54 may have a protrusion 54X. The protrusion 54X includes a straight portion 54Y and a tapered portion 54Z. The straight portion 54Y extends linearly from the first outer end 71A toward the second rotation direction R2. The tapered portion 54Z extends linearly toward a predetermined point on the outer circumference 54A of the first outer rotor core 54. The predetermined point on the outer circumference 54A of the first outer rotor core 54 is a different point from the second contact point P2 in the above modified example.

[0120] As shown in Figure 14, the rotor 40 may further include a protective member 41. The protective member 41 is positioned around the rotor core 50 and the magnets 60 so as to cover the rotor core 50 and the magnets 60. Specifically, the protective member 41 is positioned around the rotor core 50, the first magnet 70 and the second magnet 80 so as to cover the rotor core 50, the first magnet 70 and the second magnet 80. The protective member 41 includes a thinned electrical steel sheet or a thinned SPCC. The protective member 41 may include a molding member for molding the rotor 40.

[0121] As shown in Figure 15, the rotor core 50 may have both an inner connecting portion 50A and an outer connecting portion 50B. Even in this case, the first outer end 71A of the first pole surface 71 is located radially outward from the average outer circumference position AP of the rotor core 50.

[0122] As shown in Figures 16 and 17, the first magnet 70 may have tapered ends on the side of the first magnetic pole surface 71. Even in this case, the first outer end 71A of the first magnetic pole surface 71 is located radially outward from the average outer circumference position AP of the rotor core 50.

[0123] The shape of the flux barrier 52 is not particularly limited. For example, as shown in Figures 16 and 17, the flux barrier 52 may be provided at the bottom of the first magnet 70. Furthermore, as shown in Figure 17, the flux barrier 52 may have a shape that is not pointed at the tip, such as a roughly trapezoidal shape.

[0124] If the first outer end 71A of the first pole surface 71 is located radially outward from the average outer circumference position AP of the rotor core 50, the first outer end 71A may be positioned at the same location as the contact point. In this modified example, the retaining portion 53 is omitted.

[0125] The first magnet 70 does not need to overlap the second magnet 80 in the radial direction.

[0126] The rotor magnetic core 50 may be divided into multiple parts in the radial direction.

[0127] The electric motor 20 may be used in an outdoor unit for a refrigeration system or in a compressor for a refrigeration system.

[0128] The first magnet 70 may be in contact with the outer circumference 55A of the second outer rotor magnetic core 55 at its first outer end 71A. The first magnet 70 may be in contact with the outer circumference 55A of the second outer rotor magnetic core 55 at its second outer end 72A.

[0129] While embodiments of the rotor, motor, blower, and refrigeration system have been described above, it will be understood that various modifications to the form and details are possible without departing from the spirit and scope of the rotor, motor, blower, and refrigeration system described in the claims. [Explanation of Symbols]

[0130] 10...Blower, 11...Fan section, 20...Electric motor, 30...Stator, 40...Rotor, 40A...Inner circumference, 41...Protective member, 50...Rotor magnetic core, 51...Magnet arrangement section, 52...Flux barrier, 53...Retaining section, 55...Second outer rotor magnetic core, 55A...Outer circumference, 60...Magnet, 70...First magnet, 71...First magnetic pole surface, 71A...First outer end, 72...Second magnetic pole surface, 72A...Second outer end, 80...Second magnet, 81...Third magnetic pole surface, 81A...Third outer end, 100...Divided core section, 110...Core section, 111...Flexible section.

Claims

1. The rotor (40) of an external-rotating electric motor (20) Rotor magnetic core (50) and The rotor (40) is equipped with magnets (60) embedded in the rotor magnetic core (50) at predetermined intervals in the circumferential direction, The magnet (60) includes the first magnet (70), The first magnet (70) is arranged such that the angle between the mean magnetization direction (AM) of the first magnet (70) and the radial direction of the rotor (40) is greater than 0° and less than 90°. The first magnet (70) has a first pole surface (71) and a second pole surface (72) located radially inward from the first pole surface. Of the first pole surface (71), the radially outer end is located radially outward from the average outer circumference position (AP) of the rotor core (50). Rotor.

2. The second outer end (72A), located radially outward from the second pole surface (72), is located radially inward from the average outer circumference position (AP) of the rotor core (50). The rotor according to claim 1.

3. The rotor magnetic core (50) has a retaining portion (53), The retaining portion (53) covers the end of the second pole surface (72) that is radially outward. The rotor according to claim 1.

4. The magnet (60) includes a second magnet (80) that is adjacent to the first magnet (70) in the circumferential direction when the rotor (40) is viewed from the axial direction, The first magnet (70) overlaps radially with the second magnet (80), The rotor according to claim 1.

5. The length of the straight line connecting each end of the first pole surface (71) of the first magnet (70) is longer than the length obtained by dividing the length of the inner circumference (40A) of the rotor core (50) by the number of poles of the rotor (40). The rotor according to claim 1.

6. Further comprising a protective member (41), The protective member (41) is positioned around the rotor core (50) and the first magnet (70) so as to cover the rotor core (50) and the first magnet (70). The rotor according to claim 1.

7. A flux barrier (52) is provided in the portion of the rotor magnetic core (50) radially inward from the magnet arrangement portion (51) where the magnets (60) are arranged. The flux barrier (52) is surrounded by the rotor magnetic core (50) and the first magnet (70). The rotor according to claim 1.

8. A flux barrier (52) is provided in the portion of the rotor magnetic core (50) radially inward from the magnet arrangement portion (51) where the magnets (60) are arranged. The flux barrier (52) opens radially inward, The rotor according to claim 1.

9. The magnet (60) includes a second magnet (80) that is adjacent to the first magnet (70) in the circumferential direction when the rotor (40) is viewed from the axial direction, The second magnet (80) has a third pole surface (81) which is located radially outward when the rotor (40) is viewed from the axial direction, The radially outer end of the first magnetic pole surface (71) is defined as the first outer end (71A). The radially outer end of the second pole surface (72) is defined as the second outer end (72A). The radially outer end of the third magnetic pole surface (81) is defined as the third outer end (81A). When the portion of the rotor magnetic core (50) located between the first outer end (71A) and the third outer end (81A) is designated as the second outer rotor magnetic core (55), The rotor magnetic core (50) is composed of divided core portions (100) that are spaced apart from each other in the circumferential direction. The divided core portion (100) includes the second outer rotor magnetic core (55), The first magnet (70) is in contact with the outer circumference (55A) of the second outer rotor core (55) between the first outer end (71A) and the second outer end (72A). The rotor according to claim 8.

10. The thickness of the portion of the rotor magnetic core (50) radially inward from the magnet (60) is 0.5 mm or more. The rotor according to claim 8.

11. The rotor magnetic core (50) is composed of core portions (110) that are connected to each other on the radially outer side of the first magnet (70), The core portion (110) has a bendable portion (111) that can be bent so that the rotor magnetic core (50) becomes an annular shape. The rotor according to claim 8.

12. A rotor (40) according to any one of claims 1 to 11, The rotor (40) is equipped with a stator (30) positioned on the inner circumference (40A) side, Electric motor.

13. The electric motor (20) according to claim 12, The system comprises a fan section (11) driven by the aforementioned electric motor (20), Blower.

14. The electric motor (20) according to claim 12, Refrigeration equipment.

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