Rotor, electric motor, blower and air conditioner

Abstract

This rotor has N / 2 magnet poles (N an even number) and N / 2 virtual poles. The rotor has an annular rotor core centered on an axis, and multiple permanent magnets attached to the rotor core. The N / 2 magnet poles are all formed by at least one of multiple permanent magnets and the N / 2 virtual poles are all formed by the rotor core. The polar centerline of each magnet pole is defined by the straight line that passes through the axis and the center of the magnet pole in the circumferential direction of the rotor core. At least one permanent magnet forming a magnet pole has a first corner facing the outer circumference of the rotor core and furthest from the polar centerline on one side of the polar centerline, and a second corner facing the outer circumference and furthest from the polar centerline on the other side of the polar centerline. The angle θm formed by the straight line through the first corner and the axis and the straight line through the second corner and the axis satisfies θm ≥ 360[degrees].

Description

[Technical field]

[0001] The present disclosure relates to a rotor, an electric motor, a blower, and an air conditioner. [Background technology]

[0002] In recent years, electric motors with consequent-pole rotors have been developed. In consequent-pole rotors, magnetic poles are formed by permanent magnets attached to a rotor core, and virtual magnetic poles are formed by parts of the rotor core (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication WO2020 / 003341 (see Figure 2) Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, with the trend towards higher output of electric motors, there is a demand for an increase in the magnetic force of permanent magnets. In order to increase the magnetic force of a permanent magnet, it is necessary to increase the area of ​​the pole faces of the permanent magnet to increase the amount of magnetic flux. On the other hand, if the axial length of the permanent magnet is increased, the axial length of the electric motor must be increased accordingly, which leads to an increase in manufacturing costs.

[0005] The present disclosure has been made to solve the above-mentioned problems, and aims to increase the magnetic force of a permanent magnet while suppressing an increase in manufacturing costs. [Means for solving the problem]

[0006] The rotor of the present disclosure has N / 2 magnet poles (N is an even number) and N / 2 virtual poles. The rotor has an annular rotor core centered on the axis and a plurality of permanent magnets attached to the rotor core. Each of the N / 2 magnet poles is formed by at least one permanent magnet among the plurality of permanent magnets, and each of the N / 2 virtual poles is formed by a portion of the rotor core. The pole centerline of each magnet pole is defined by a straight line passing through the center of the magnet pole in the circumferential direction of the rotor core and the axis. At least one permanent magnet forming the magnet pole has a first corner portion facing the outer periphery of the rotor core and furthest from the pole centerline on one side of the pole centerline, and a second corner portion facing the outer periphery and furthest from the pole centerline on the other side of the pole centerline. The rotor core has, at each magnet pole, a magnet insertion hole in which the at least one permanent magnet is disposed, and a nonmagnetic portion formed between the magnet insertion hole and the outer periphery of the rotor core and extending in the circumferential direction. A first gap and a second gap are formed at each end of two magnet insertion holes adjacent to each virtual magnetic pole on either side of the virtual magnetic pole. The angle θm between a line passing through the first corner and the axis and a line passing through the second corner and the axis satisfies θm≧360 / N [degrees]. A point in the first gap that faces the second gap and is closest to the outer periphery is defined as a first point, and a point in the second gap that faces the first gap and is closest to the outer periphery is defined as a second point. A point in the first gap that faces the second gap and is closest to the inner periphery of the rotor core is defined as a third point, and a point in the second gap that faces the first gap and is closest to the inner periphery is defined as a fourth point. An angle θv1 between a line passing through the first point and the axis and a line passing through the second point and the axis, and an angle θv2 between a line passing through the third point and the axis and a line passing through the fourth point and the axis satisfy θv1>θv2. Effect of the Invention

[0007] According to the present disclosure, since the angle θm is equal to or greater than 360 / N [degrees], the area of ​​the magnetic pole face of the permanent magnet per unit length in the axial direction can be increased, thereby increasing the magnetic force of the permanent magnet while suppressing increases in manufacturing costs. [Brief description of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view showing an electric motor according to a first embodiment. [Diagram 2] 1 is a cross-sectional view showing a rotor according to a first embodiment. [Diagram 3] 2 is an enlarged view showing a part of the rotor according to the first embodiment. FIG. [Figure 4] 2 is a diagram for explaining the arrangement of magnetic poles of the rotor according to the first embodiment. FIG. [Diagram 5] 1A is a diagram showing magnet poles of a rotor according to a first embodiment, and FIG. 1B is an enlarged diagram showing a region including an end portion of a permanent magnet. [Figure 6] 2 is a schematic diagram showing magnetic flux flowing through each magnetic pole of the rotor according to the first embodiment. FIG. [Figure 7]4 is a cross-sectional view showing another example of the configuration of the rotor according to the first embodiment. FIG. [Figure 8] 8 is an enlarged cross-sectional view of a portion of the rotor in FIG. 7. [Figure 9] 1 is a vertical cross-sectional view showing an electric motor according to a first embodiment. [Figure 10] FIG. 4 is a cross-sectional view showing a rotor according to a first modified example. [Figure 11] FIG. 11 is a cross-sectional view showing a rotor according to a second modified example. [Figure 12] FIG. 11 is a cross-sectional view showing a rotor according to a second embodiment. [Figure 13] 13 is an enlarged cross-sectional view of a portion of the rotor of FIG. 12. [Figure 14] FIG. 1A is a diagram showing an air conditioner to which the electric motors of the respective embodiments can be applied, and FIG. 1B is a cross-sectional view showing an outdoor unit of the air conditioner. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Embodiment 1 <Configuration of electric motor 2> 1 is a cross-sectional view showing an electric motor 2 according to a first embodiment. The electric motor 2 is an inner rotor type electric motor including a rotatable rotor 1 and an annular stator 5 provided so as to surround the rotor 1. Between the stator 5 and the rotor 1, an air gap G of, for example, 0.4 to 0.7 mm is provided.

[0010] In the following, the axis around which the rotor 1 rotates is the axis Ax, and the direction of the axis Ax is referred to as the "axial direction." The circumferential direction around the axis Ax is referred to as the "circumferential direction," and the radial direction around the axis Ax is referred to as the "radial direction." Note that FIG. 1 is a cross-sectional view of the rotor 1 taken along a plane perpendicular to the axis Ax.

[0011] <Stator configuration> The stator 5 has a stator core 50 and a coil 55 wound around the stator core 50. The stator core 50 is made by stacking magnetic laminated elements in the axial direction and fixing them by caulking or the like. The laminated elements are made of a core material containing iron (Fe) as a main component, such as an electromagnetic steel sheet. The thickness of the laminated elements is, for example, 0.2 mm to 0.5 mm.

[0012] The stator core 50 has an annular yoke 52 centered on the axis Ax, and a plurality of teeth 51 extending radially inward from the yoke 52. The teeth 51 are arranged at equal intervals in the circumferential direction. The number of teeth 51 is 12 here, but is not limited to 12. A slot 53, which is a space for accommodating a coil 55, is formed between adjacent teeth 51.

[0013] The radially inner tips of the teeth 51 have a circumferential width greater than other portions of the teeth 51. The tips of the teeth 51 face the outer periphery of the rotor 1 via the air gap G described above.

[0014] An insulating portion 54 is attached to the stator core 50. The insulating portion 54 is interposed between the stator core 50 and the coil 55 and insulates the stator core 50 from the coil 55. The insulating portion 54 is formed by molding a resin integrally with the stator core 50, or by assembling a resin molded body molded as a separate part to the stator core 50.

[0015] The insulating section 54 is made of an insulating resin, such as polybutylene terephthalate (PBT), polyphenylene sulfide (PPS), liquid crystal polymer (LCP), polyethylene terephthalate (PET), etc. The insulating section 54 can also be made of an insulating resin film having a thickness of 0.035 to 0.4 mm.

[0016] The coil 55 is wound around the teeth 51 via the insulating portion 54. The coil 55 has a conductor made of copper or aluminum and a coating that covers the conductor. The winding method of the coil 55 may be concentrated winding or distributed winding.

[0017] <Rotor configuration> 2 is a cross-sectional view showing the rotor 1. The rotor 1 has a rotating shaft 40, an annular rotor core 10 that surrounds the rotating shaft 40 from the radial outside, and a resin portion 30 provided between them.

[0018] The rotating shaft 40 is a shaft whose central axis is the axis line Ax. The rotating shaft 40 is made of a metal such as iron, nickel (Ni), or chromium (Cr).

[0019] The resin part 30 supports the rotor core 10 with respect to the rotating shaft 40, and is made of a non-magnetic material, more specifically, a thermoplastic resin such as PBT. The resin part 30 is formed by molding the rotor core 10 and the rotating shaft 40 with resin. The resin part 30 may be provided with a rib or a cavity.

[0020] Here, the resin portion 30 is provided between the rotor core 10 and the rotating shaft 40 , but instead of providing the resin portion 30 , the rotating shaft 40 may be fitted into a shaft hole formed in the rotor core 10 .

[0021] The rotor core 10 is formed by stacking magnetic laminated elements in the axial direction and fixing them by caulking or the like. The laminated elements are made of a core material whose main component is iron, such as an electromagnetic steel sheet. The laminated elements have a thickness of, for example, 0.2 to 0.5 mm. Both the outer periphery 10a and the inner periphery 10b of the rotor core 10 extend in the circumferential direction centered on the axis Ax.

[0022] A plurality of magnet insertion holes 11 are formed along the outer periphery 10a of the rotor core 10. The magnet insertion holes 11 are arranged at equal intervals in the circumferential direction. The magnet insertion holes 11 extend from one end to the other end in the axial direction of the rotor core 10. The magnet insertion holes 11 extend linearly in a direction perpendicular to a straight line passing through the circumferential center and the axis Ax (i.e., a pole center line C1 described later). The number of magnet insertion holes 11 here is five.

[0023] A permanent magnet 20 is disposed in each magnet insertion hole 11. The permanent magnet 20 is flat, has a width in the circumferential direction, and has a thickness in the radial direction. The permanent magnet 20 is magnetized in the thickness direction. The permanent magnet 20 is made of a rare earth magnet mainly composed of neodymium (Nd) or samarium (Sm), for example. It may also be made of a ferrite magnet mainly composed of iron.

[0024] A magnetic pole P1 is formed by the permanent magnets 20. The permanent magnets 20 have magnetic pole faces of the same polarity (e.g., N pole) facing the outer periphery 10a of the rotor core 10. Therefore, a virtual magnetic pole P2 of the opposite polarity (e.g., S pole) to the permanent magnets 20 is formed between adjacent permanent magnets 20 in the rotor core 10.

[0025] That is, the rotor 1 has five magnet poles P1 and five virtual magnetic poles P2 arranged alternately in the circumferential direction. Therefore, the rotor 1 has 10 poles. This type of rotor structure is called a consequent pole type. The number of poles of the rotor 1 is not limited to 10 poles, and may be any even number.

[0026] If the number of poles of the rotor 1 is N (N is an even number), the number of magnet poles P1 is expressed as N / 2, and the number of virtual magnetic poles P2 is also expressed as N / 2. The magnet poles P1 are also referred to as first magnetic poles, and the virtual magnetic poles P2 are also referred to as second magnetic poles.

[0027] Here, one permanent magnet 20 is placed in each magnet insertion hole 11, and the magnetic pole P1 is formed by one permanent magnet 20. However, two or more permanent magnets may be placed in each magnet insertion hole 11, and the magnetic pole P1 may be formed by the two or more permanent magnets (see FIGS. 10 and 11). In addition, the permanent magnet 20 does not necessarily have to be flat.

[0028] The circumferential center of magnet pole P1, i.e., the circumferential center of magnet insertion hole 11, is the pole center of magnet pole P1. A straight line passing through the pole center of magnet pole P1 and axis Ax is referred to as pole center line C1. Similarly, the circumferential center of virtual magnetic pole P2 is the pole center of virtual magnetic pole P2. A straight line passing through the pole center of virtual magnetic pole P2 and axis Ax is referred to as pole center line C2.

[0029] The outer periphery 10a of the rotor core 10 has a shape that is a so-called "flower circle shape" in which the outer diameter is maximum at the pole center of the magnetic poles P1, P2 and is minimum at the inter-pole portion between the magnetic poles P1, P2. However, the shape of the outer periphery 10a of the rotor core 10 is not limited to a flower circle shape and may be, for example, a circular shape.

[0030] In the consequent pole type rotor 1, since no actual magnet exists at the virtual magnetic pole P2, the magnetic flux that passes through the virtual magnetic pole P2 easily flows to the rotating shaft 40. The resin part 30 disposed between the rotor core 10 and the rotating shaft 40 acts to suppress magnetic flux leakage to the rotating shaft 40.

[0031] Flux barriers 12, which are gaps, are formed at both circumferential ends of magnet insertion hole 11. A thin-walled portion is formed between outer periphery 10a of rotor core 10 and flux barrier 12. The radial thickness of the thin-walled portion is desirably equal to the thickness of the laminated elements of rotor core 10 in order to suppress leakage flux between adjacent magnetic poles.

[0032] The above-mentioned virtual magnetic pole P2 is formed between the flux barriers 12 of adjacent magnet insertion holes 11. That is, the flux barriers 12 define both circumferential ends of the virtual magnetic pole P2. Therefore, the above-mentioned pole center line C2 of the virtual magnetic pole P2 is a straight line passing through the axis Ax and the circumferential midpoint of the two flux barriers 12 on both sides of the virtual magnetic pole P2.

[0033] Fig. 3 is an enlarged cross-sectional view of the rotor 1. Hatching of the rotor core 10 and the resin part 30 is omitted in Fig. 3 and Figs. 4 to 8, 10 to 13 described later. As shown in Fig. 3, the permanent magnet 20 has a magnetic pole face 20a on the outer periphery 10a side, a magnetic pole face 20b on the inner periphery 10b side, and end faces 20c on both sides in the circumferential direction. Both of the magnetic pole faces 20a and 20b extend in a direction perpendicular to the pole center line C1.

[0034] The magnet insertion hole 11 has an outer edge 11a on the outer periphery 10a side and an inner edge 11b on the inner periphery 10b side. Both the outer edge 11a and the inner edge 11b extend in a direction perpendicular to the pole center line C1. Steps 11c are formed on both ends of the inner edge 11b of the magnet insertion hole 11.

[0035] An outer edge 11a of the magnet insertion hole 11 faces the pole surface 20a of the permanent magnet 20, and an inner edge 11b of the magnet insertion hole 11 faces the pole surface 20b of the permanent magnet 20. Two stepped portions 11c of the magnet insertion hole 11 face both end surfaces 20c of the permanent magnet 20. This positions the permanent magnet 20 in the magnet insertion hole 11.

[0036] The flux barrier 12 has an outer edge 12a extending along the outer periphery 10a of the rotor core 10, a side edge 12b which is the edge on the virtual magnetic pole P2 side, and a base edge 12c extending between the side edge 12b and the step portion 11c.

[0037] In addition, slits 13 are formed as non-magnetic portions between the magnet insertion holes 11 and the outer periphery 10a of the rotor core 10 in the radial direction. Here, two slits 13 are formed on both sides of the pole center line C1. The slits 13 extend in the circumferential direction.

[0038] The slits 13 are desirably formed contiguous with the flux barrier 12 on the polar center line C1 side of the flux barrier 12. An example in which the slits 13 are formed apart from the flux barrier 12 will be described with reference to Figs.

[0039] On one side (left side in FIG. 3) of the pole center line C1 of each magnet pole P1, the corner between the pole face 20a and the end face 20c of the permanent magnet 20 is defined as corner R1. On the other side (right side in FIG. 3) of the pole center line C1, the corner between the pole face 20a and the end face 20c of the permanent magnet 20 is defined as corner R2.

[0040] Corner R1 corresponds to the corner that faces outer periphery 10a of rotor core 10 and is the farthest corner from pole center line C1 on one side of pole center line C1. Corner R2 corresponds to the corner of permanent magnet 20 that faces outer periphery 10a of rotor core 10 and is the farthest corner from pole center line C1 on the other side of pole center line C1.

[0041] Both corners R1 and R2 of the permanent magnet 20 are located within a space surrounded by the outer edge 12a, the side edge 12b, and the base edge 12c of the flux barrier 12. The corner R1 is also referred to as a first corner, and the corner R2 is also referred to as a second corner.

[0042] 4 is a diagram for explaining the arrangement of the magnetic poles P1 and virtual magnetic poles P2 of the rotor 1. A straight line passing through the corner R1 of the permanent magnet 20 and the axis Ax is defined as a straight line L1. Similarly, a straight line passing through the corner R2 of the permanent magnet 20 and the axis Ax is defined as a straight line L2.

[0043] The angle between the straight lines L1 and L2 is defined as an angle θm. This angle θm represents the range that the permanent magnet 20 occupies in the circumferential direction in terms of angle.

[0044] If the number of poles of the rotor 1 is represented by N (N is an even number), the angle θm satisfies θm ≧ 360 / N. When the number of poles N is 10, 360 / N is 36 degrees, so the angle θm needs to be 36 degrees or greater. As an example, the angle θm is 40 degrees.

[0045] That is, in this embodiment, the range occupied by the permanent magnets 20 is equal to or greater than the angle obtained by equally dividing 360 degrees by the number of poles N (ie, 360 / N degrees).

[0046] Of the two flux barriers 12 adjacent in the circumferential direction across the virtual magnetic pole P2, the point on the side edge 12b of one flux barrier 12 that is closest to the outer periphery 10a is designated as point R3, and the point on the side edge 12b of the other flux barrier 12 that is closest to the outer periphery 10a is designated as point R4.

[0047] A straight line passing through point R3 and axis Ax is called line L3, and a straight line passing through point R4 and axis Ax is called line L4. The angle between line L3 and line L4 is called angle θv. This angle θv represents the range that virtual magnetic pole P2 occupies in the circumferential direction in angle.

[0048] The angle θv satisfies θv<360 / N and also satisfies θv<θm. The angle θv is, for example, 30 degrees. That is, the angle θv occupied by the virtual magnetic pole P2 is smaller than the angle θm occupied by the permanent magnet 20.

[0049] The flux barrier 12 on one side is also referred to as a first gap, and the flux barrier 12 on the other side is also referred to as a second gap. 1 Point R4 is also called the first point. 2 It is also called the point.

[0050] Fig. 5(A) is an enlarged view of the magnet pole P1. Fig. 5(B) is an enlarged view of the area including the end of the permanent magnet 20. As described above, slits 13 are formed on both sides of the pole center line C1 of the magnet pole P1. The area between the two slits 13 is also referred to as the inter-slit area.

[0051] Slit 13 has an outer edge 13a extending along outer periphery 10a of rotor core 10, an inner edge 13b radially opposed to outer edge 13a, and a tip edge 13c formed on the pole center line C1 side.

[0052] Here, the outer edge 13a of the slit 13 extends on an extension line of the outer edge 12a of the flux barrier 12. Between the inner edge 13b of the slit 13 and the outer edge 11a of the magnet insertion hole 11, a curved portion 13d is formed.

[0053] 5(B), the slit 13 has a length A in the circumferential direction and a width B in the radial direction, where the length A and the width B have a relationship of A>B. The length A is the distance from the tip edge 13c of the slit 13 to the curved portion 13d. The width B is the distance between the outer edge 13a and the inner edge 13b.

[0054] A core region 14 is formed between the inner edge 13b of the slit 13 and the outer edge 11a of the magnet insertion hole 11. The core region 14 constitutes a part of the magnetic path from the permanent magnet 20 to the inter-slit region. The core region 14 has a width W in the radial direction. The width W is the radial distance between the inner edge 13b of the slit 13 and the outer edge 11a of the magnet insertion hole 11.

[0055] Since the inner edge 13b of the slit 13 extends along the outer periphery 10a of the rotor core 10, the distance from the outer edge 11a of the magnet insertion hole 11 increases as the slit approaches the pole center line C1. Therefore, the radial width W of the core region 14 increases as the slit approaches the pole center line C1.

[0056] 4, of the two slits 13 in the magnetic pole P1 of the magnet, the point closest to the outer periphery 10a on the leading edge 13c of one of the slits 13 is designated as point R5. The point closest to the outer periphery 10a on the leading edge 13c of the other slit 13 is designated as point R6. The straight line passing through point R5 and the axis Ax is designated as line L5, and the straight line passing through point R5 and the axis Ax is designated as line L6.

[0057] The angle between the straight lines L5 and L6 is defined as angle θs. This angle θs represents the range of the inter-slit region in the circumferential direction in terms of angle. The angle θs is smaller than the above angle θm, and therefore satisfies θs<θm and θs≦360 / N [degrees]. An example of the angle θs is 25 degrees.

[0058] The one slit 13 is also called a first non-magnetic portion, and the other slit 13 is also called a second non-magnetic portion. 5 Point R6 is also called the first point. 6 It is also called the point.

[0059] <effect> Next, the operation of the first embodiment will be described. The larger the area of ​​the pole face 20a of the permanent magnet 20, the greater the amount of magnetic flux emitted from the pole face 20a, and the greater the magnetic force. However, increasing the axial length of the permanent magnet 20 increases the axial length of the electric motor 2, which leads to an increase in the size of the electric motor 2 or an increase in manufacturing costs. For this reason, it is desirable to increase the area of ​​the pole face 20a of the permanent magnet 20 per unit axial length.

[0060] In the first embodiment, the angle θm of the permanent magnet 20 is equal to or larger than 360 / N [degrees]. Therefore, the width of the magnetic pole face 20a of the permanent magnet 20 can be increased, and the area of ​​the magnetic pole face 20a of the permanent magnet 20 per unit length in the axial direction can be increased. This increases the amount of magnetic flux coming out of the magnetic pole face 20a, and increases the magnetic force of the permanent magnet 20.

[0061] In a non-consequential pole rotor in which permanent magnets are arranged on all magnetic poles, if the angle θm is 360 / N [degrees] or more, adjacent permanent magnets will interfere with each other, so the angle θm is set to less than 360 / N [degrees].

[0062] In contrast, the rotor 1 of the first embodiment is a consequent pole type, and no permanent magnet is disposed at the virtual magnetic pole P2. Therefore, it is possible to make the angle θm occupied by the permanent magnet 20 equal to or larger than 360 / N [degrees].

[0063] In this embodiment 1, the magnetic force can be increased without increasing the axial length of the permanent magnet 20, so that the output of the motor 2 can be increased while suppressing any increase in the manufacturing cost of the motor 2.

[0064] Furthermore, because the area of ​​the magnetic pole faces 20a of the permanent magnets 20 per unit length in the axial direction is increased, the axial length of the electric motor 2 required to obtain the same magnetic force can be shortened. As a result, the amount of core material for the rotor core 10 and the stator core 50 can be reduced, and the overall length of the coils 55 can be shortened. In other words, the manufacturing cost of the electric motor 2 can be reduced, and efficiency can be improved.

[0065] If the angle θm of the permanent magnets 20 exceeds 720 / N [degrees], it is not possible to ensure a space for forming the virtual magnetic pole P2 between adjacent permanent magnets 20. Therefore, the angle θm is set to satisfy 360 / N [degrees]≦θm<720 / N [degrees].

[0066] Here, when the angle θm is set to 360 / N [degrees] or more as described above, the angle θm of the permanent magnet 20 becomes larger than the angle θv of the virtual magnetic pole P2 (i.e., θm>θv). Therefore, if the magnetic pole P1 is an N pole and the virtual magnetic pole P2 is an S pole, the width of the N pole on the surface of the rotor 1 becomes wider than the width of the S pole.

[0067] If there is a large difference in width between the north and south poles on the surface of the rotor 1, this can cause vibration and noise. Therefore, the rotor 1 of the first embodiment has two slits 13 that limit the magnetic path on both sides of the pole center line C1 of the magnet pole P1. The slits 13 are long in the circumferential direction. This shape is suitable for controlling the flow of magnetic flux.

[0068] 6 is a schematic diagram for explaining the flow of magnetic flux in the magnetic pole P1 and the virtual magnetic pole P2 of the rotor 1. Here, the explanation will be given assuming that the magnetic pole face 20a of the permanent magnet 20 of the magnetic pole P1 is an N pole.

[0069] The magnetic flux emitted from the pole face 20a of the permanent magnet 20 flows toward the outer periphery 10a of the rotor core 10. The slits 13 formed on the outer periphery 10a side of the magnet insertion holes 11 are lined with air or other non-magnetic material, preventing the passage of the magnetic flux.

[0070] Therefore, the magnetic flux emitted from the pole face 20a of the permanent magnet 20 passes through the region between the two slits 13, i.e., the inter-slit region, toward the stator 5. The angle occupied by the inter-slit region is the above-mentioned angle θs. This angle θs is smaller than the angle θm occupied by the permanent magnet 20. In other words, the slits 13 have the role of narrowing the flow of the magnetic flux emitted from the pole face 20a of the permanent magnet 20.

[0071] By bringing the angle θs of the inter-slit area of ​​the magnetic pole P1 closer to the angle θv of the virtual magnetic pole P2, it is possible to make the widths of the N poles and S poles on the surface of the rotor 1 closer to equal, thereby reducing vibrations and noise caused by the difference in width between the N poles and S poles.

[0072] Here, when the angle θs of the inter-slit region of the magnetic pole P1 and the angle θv of the virtual magnetic pole P2 are equal to each other (ie, θs=θv), the difference in width between the N pole and the S pole is minimized.

[0073] However, since there is no magnet insertion hole in virtual magnetic pole P2, if the angle θs of the inter-slit area of ​​magnet pole P1 and the angle θv of virtual magnetic pole P2 are made equal, the core amount of virtual magnetic pole P2 becomes greater than the core amount of magnet pole P1, and therefore the magnetic attraction force between the rotor 1 and the stator 5 becomes greater in virtual magnetic pole P2. Note that the core amount refers to the amount of core material such as electromagnetic steel sheet.

[0074] In contrast, if θv<θs is satisfied, the core amount of magnet pole P1 and the core amount of virtual magnetic pole P2 can be made closer to each other, and vibrations caused by differences in magnetic attraction forces can be reduced.For these reasons, it is desirable that the angle θs of the inter-slit area of ​​magnet pole P1 and the angle θv of virtual magnetic pole P2 satisfy θv≦θs.

[0075] Here, two slits 13 are formed on both sides of the pole center line C1, but since even one slit 13 can limit the magnetic path, the number of slits 13 may be one.

[0076] 5(B) constitutes a part of the magnetic path from the magnetic pole face 20a of the permanent magnet 20 to the inter-slit region. When the magnetic flux coming out of the magnetic pole face 20a of the permanent magnet 20 flows into the inter-slit region, the amount of magnetic flux increases closer to the pole center line C1.

[0077] Here, the radial width W of the core region 14 becomes wider as it approaches the pole center line C1, so that local concentration of magnetic flux and the resulting magnetic saturation can be suppressed, and the magnetic flux of the permanent magnet 20 can be effectively utilized.

[0078] Fig. 7 is a cross-sectional view showing another configuration example of the rotor 1. Fig. 8 is an enlarged view of the magnet pole P1 of the rotor 1 in Fig. 7. As shown in Fig. 7, in this configuration example, slits 15 are formed on both sides of the pole center line C1 of each magnet pole P1, and each slit 15 is formed away from the flux barrier 12.

[0079] 8, the slit 15 has an outer edge 15a on the outer periphery 10a side of the rotor core 10, an inner edge 15b on the magnet insertion hole 11 side, a tip edge 15c on the pole center line C1 side, and a base edge 15d on the flux barrier 12 side. The circumferential length A and radial width B of the slit 15 have a relationship of A>B.

[0080] Each slit 15 functions to restrict the magnetic path of the magnet pole P1, and an inter-slit region is formed between two slits 15. The angle occupied by the inter-slit region is the angle θs described above. Meanwhile, since the slits 15 are formed away from the flux barrier 12, a bridge portion 16 is formed between the slits 15 and the flux barrier 12.

[0081] Therefore, the magnetic flux emitted from the pole surface 20a of the permanent magnet 20 passes not only through the region between the slits but also through the bridge portion 16. That is, the function of restricting the magnetic path of the magnet pole P1 is reduced by the amount of magnetic flux flowing through the bridge portion 16.

[0082] In contrast, when the slits 13 are formed continuously with the flux barrier 12 as shown in Figures 1 to 6, the exit of the magnetic flux from the rotor 1 toward the stator 5 is limited to the area between the slits, so that the slits 13 can effectively function to limit the magnetic path of the magnet pole P1.

[0083] Although the case where the magnet pole P1 is an N pole has been described here, the case where the magnet pole P1 is an S pole is also similar. Since the flux barrier 12 is part of the magnet insertion hole 11, it can also be said that the slit 13 is formed continuously with the magnet insertion hole 11 in the configuration shown in Figures 1 to 6.

[0084] <Configuration of molded electric motor> 9 is a vertical cross-sectional view showing a molded motor to which electric motor 2 of embodiment 1 is applied. Stator 5 is covered with molded resin part 60 to form molded stator 6.

[0085] The molded resin part 60 is made of a thermosetting resin such as BMC (bulk molding compound). The molded resin part 60 has an opening 61 on the left side in FIG. 9 and a bearing support part 62 on the opposite side. The rotor 1 is inserted into the hollow part inside the stator 5 from the opening 61.

[0086] A metal bracket 44 is attached to an opening 61 of the molded resin part 60. A bearing 41 is held by this bracket 44. A cap 43 is attached to the outside of the bracket 44 to prevent water and the like from entering the bearing 41. A bearing 42 is held by the bearing support part 62. The rotating shaft 40 is supported by the bearings 41 and 42.

[0087] The rotating shaft 40 protrudes from the stator 5 to the left in Fig. 9, and an impeller of a blower, for example, is attached to a tip end 40a of the rotating shaft 40. Therefore, the protruding side of the rotating shaft 40 (the left side in Fig. 9) is referred to as the "load side," and the opposite side (the right side in Fig. 9) is referred to as the "anti-load side."

[0088] A circuit board 70 is disposed on the anti-load side of the stator 5. A magnetic sensor 71 and a drive circuit 72 for driving the electric motor 2 are mounted on the circuit board 70, and lead wires 73 are wired thereto.

[0089] The lead wires 73 include a power supply lead wire for supplying power to the coil 55 of the stator 5, and a sensor lead wire for transmitting a signal from the magnetic sensor 71 to the outside. A lead wire outlet part 74 for drawing the lead wires 73 to the outside is attached to the outer periphery of the molded resin part 60.

[0090] The resin portion 30 of the rotor 1 is provided between the rotor core 10 and the rotating shaft 40, and also covers both axial end faces of the rotor core 10. A sensor magnet 17 is disposed on the anti-load side of the rotor core 10 and is held by the resin portion 30. 17 is an annular magnet, with similar magnetic poles to that of rotor 1.

[0091] The magnetic sensor 71 mounted on the circuit board 70 is, for example, a Hall IC, and has a sensor magnet 17 The magnetic sensor 71 detects the magnetic flux of the rotor 1. The drive circuit 72 detects the rotational position of the rotor 1 based on the detection signal of the magnetic sensor 71 and controls the current flowing through the coil 55. Note that instead of detecting the rotational position of the rotor 1, a sensorless control may be performed in which the rotational position of the rotor 1 is estimated from the current flowing through the coil 55 or the like.

[0092] Further, here, the stator 5 is covered with the molded resin portion 60, but the stator 5 may be fitted inside a metal shell.

[0093] <Effects of the embodiment> As described above, the rotor 1 of the first embodiment has the rotor core 10 and the permanent magnets 20, and N / 2 (N is an even number) magnetic poles P1 are formed by the permanent magnets 20, and N / 2 virtual magnetic poles P2 are formed by the rotor core 10. The permanent magnets 20 have a corner R1 that faces the outer periphery 10a of the rotor core 10 and is furthest on one side from the pole center line C1, and a corner R2 that faces the outer periphery 10a of the rotor core 10 and is furthest on the other side from the pole center line C1. The angle θm between the straight line L1 passing through the corner R1 and the axis Ax and the straight line L2 passing through the corner R2 and the axis Ax satisfies θm≧360 / N [degrees].

[0094] This configuration makes it possible to increase the area of ​​the magnetic pole face 20a of the permanent magnet 20 per unit length in the axial direction, thereby increasing the magnetic force of the permanent magnet 20. In other words, it is possible to increase the output and improve the efficiency while suppressing an increase in the manufacturing cost of the electric motor 2.

[0095] In addition, slits 13 are formed between the permanent magnets 20 and the outer periphery 10a of the rotor core 10 as non-magnetic portions extending in the circumferential direction, thereby restricting the magnetic path of the magnet pole P1. This makes it possible to suppress the difference in width between the N pole and the S pole on the surface of the rotor 1, thereby reducing vibration and noise.

[0096] In particular, if the slit 13 is formed contiguous to the magnet insertion hole 11, the effect of limiting the magnetic path of the magnet pole P1 can be enhanced compared to when the slit 13 is formed away from the magnet insertion hole 11.

[0097] In addition, a core region 14 is formed between the slit 13 and the magnet insertion hole 11, and the width W of the core region 14 increases as it approaches the pole center line C1, thereby suppressing the occurrence of magnetic saturation in the magnetic path from the pole face 20a of the permanent magnet 20 to the region between the slits.

[0098] Furthermore, if the point on the leading edge 13c of one of the two slits 13 in each magnet pole P1 that is closest to the outer periphery 10a is designated as point R5, and the point on the leading edge 13c of the other slit 13 that is closest to the outer periphery 10a is designated as point R6, the angle θs formed by the line L5 passing through point R5 and the axis Ax, and the line L6 passing through point R6 and the axis Ax, satisfies θs≦360 / N [degrees]. Therefore, the widths of the N poles and S poles on the surface of the rotor 1 can be made closer to equal, reducing vibration and noise.

[0099] In addition, when the point on the side edge 12b of one of the flux barriers 12 on both sides in the circumferential direction of the imaginary magnetic pole P2 is the point closest to the outer periphery 10a, which is defined as point R3, and the point on the side edge 12b of the other flux barrier 12 is the point closest to the outer periphery 10a, which is defined as point R4, a straight line passing through point R3 and the axis Ax is defined asL3 The angle θv between point R4 and a straight line L4 passing through the axis Ax satisfies θv≦θs. Therefore, the widths of the N poles and S poles on the surface of the rotor 1 are made closer to equal, and the variation in the magnetic attraction force between the rotor 1 and the stator 5 is reduced, thereby reducing vibration and noise.

[0100] Variation 1. 10 is a cross-sectional view showing a rotor 1A of Modification 1. In the rotor 1 of the above-described embodiment 1, one permanent magnet 20 is inserted into each magnet insertion hole 11. In contrast, in the rotor 1A of Modification 1, two permanent magnets 21, 22 are inserted into each magnet insertion hole 11.

[0101] The rotor core 10 of the rotor 1A is formed with N / 2 magnet insertion holes 11. Each magnet insertion hole 11 has a V-shape with its circumferential center protruding toward the inner circumference 10b of the rotor core 10. In each magnet insertion hole 11, a permanent magnet 21 is arranged on one side of the circumferential center, and a permanent magnet 22 is arranged on the other side. The permanent magnet 21 is also referred to as a first permanent magnet, and the permanent magnet 22 is also referred to as a second permanent magnet.

[0102] The permanent magnet 21 has a magnetic pole face 21a on the outer periphery 10a side, a magnetic pole face 21b on the inner periphery 10b side, and end faces 21c on both circumferential ends. The permanent magnet 22 has a magnetic pole face 22a on the outer periphery 10a side, a magnetic pole face 22b on the inner periphery 10b side, and end faces 22c on both circumferential ends.

[0103] The magnet insertion hole 11 has an outer edge 11a on the outer periphery 10a side and an inner edge 11b on the inner periphery 10b side, and both the outer edge 11a and the inner edge 11b extend in a V-shape. In addition, a step portion 11c is formed on both circumferential sides of the inner edge 11b.

[0104] An outer edge 11a of the magnet insertion hole 11 faces the magnetic pole faces 21a, 22a of the permanent magnets 21, 22. An inner edge 11b of the magnet insertion hole 11 faces the magnetic pole faces 21b, 22b of the permanent magnets 21, 22. A step portion 11c of the magnet insertion hole 11 faces the end faces 21c, 22c of the permanent magnets 21, 22 that are away from the pole center line C1.

[0105] A magnet pole P1 serving as a first magnetic pole is formed by the permanent magnets 21 and 22 arranged in each magnet insertion hole 11. A virtual magnetic pole P2 serving as a second magnetic pole is formed between adjacent magnet poles P1.

[0106] The pole center line C1 is a straight line that passes through the axis Ax and the circumferential center of the magnet pole P1, i.e., the circumferential center of the magnet insertion hole 11. The pole center line C2 is a straight line that passes through the circumferential center of the virtual magnetic pole P2 and the axis Ax.

[0107] In the permanent magnet 21, a corner between the magnetic pole face 21a and the end face 21c away from the pole center line C1 is defined as a corner R1. In the permanent magnet 22, a corner between the magnetic pole face 22a and the end face 22c away from the pole center line C1 is defined as a corner R2. Both corners R1 and R2 of the permanent magnets 21 and 22 are located within the flux barrier 12.

[0108] Corner R1 faces outer periphery 10a of rotor core 10 and corresponds to the corner furthest from pole center line C1 on one side (left side in FIG. 10) of pole center line C1. Corner R2 faces outer periphery 10a of rotor core 10 and corresponds to the corner furthest from pole center line C1 on the other side (right side in FIG. 10) of pole center line C1.

[0109] The angle between a straight line L1 passing through the corner R1 of the permanent magnet 20 and the axis Ax and a straight line L2 passing through the corner R2 and the axis Ax is defined as an angle θm. This angle θm represents the range occupied by the permanent magnets 21 and 22 in the circumferential direction in angle.

[0110] As in the first embodiment, the angle θm satisfies θm ≧ 360 / N. Because the angle θm is 360 / N [degrees] or more, the area of ​​the magnetic pole faces 21a, 22a of the permanent magnets 21, 22 per unit length in the axial direction can be increased.

[0111] As in the first embodiment, slits 13 are formed on the outer periphery 10a side of magnet insertion hole 11. In addition, angle θs of the inter-slit area and angle θv of virtual magnetic pole P2 are also as described in the first embodiment.

[0112] Except for the above points, the rotor 1A of the first modification is configured similarly to the rotor 1 of the first embodiment.

[0113] Although an example in which magnet insertion hole 11 has a V-shape has been described here, two permanent magnets 21, 22 may be arranged in magnet insertion hole 11 that has a linear shape.

[0114] Thus, according to the first modification, even in the rotor 1A in which two permanent magnets 21, 22 are inserted into the magnet insertion hole 11, by setting the angle θm occupied by the permanent magnets 21, 22 to 360 / N [degrees] or more, it is possible to increase the area of ​​the magnetic pole faces 21a, 22a of the permanent magnets 21, 22 per unit length in the axial direction, thereby increasing the magnetic force. This makes it possible to increase the output and improve the efficiency while suppressing an increase in the manufacturing cost of the electric motor 2.

[0115] Variation 2. 11 is a cross-sectional view showing a rotor 1B of modified example 2. In the rotor 1 of embodiment 1 described above, one permanent magnet 20 is inserted into each magnet insertion hole 11. In contrast, in the rotor 1B of modified example 2, three permanent magnets 23, 24, 25 are inserted into each magnet insertion hole 11.

[0116] The rotor core 10 of the rotor 1B is formed with N / 2 magnet insertion holes 11. Each magnet insertion hole 11 has a central portion located in the circumferential center, and two inclined portions extending from both ends of the central portion toward the outer periphery 10a of the rotor core 10. The two inclined portions are inclined such that the distance between the two inclined portions increases the further away from the central portion. In other words, the magnet insertion hole 11 has a bathtub shape.

[0117] The permanent magnet 23 is disposed in the center of the magnet insertion hole 11, and the permanent magnets 24, 25 are disposed in the two inclined portions. Both the permanent magnets 24, 25 are inclined so that the distance between the permanent magnets 24, 25 increases as they move away from the permanent magnet 23. In other words, the permanent magnets 23, 24, 25 are disposed in a bathtub shape. The permanent magnet 23 is also referred to as the first permanent magnet, the permanent magnet 24 as the second permanent magnet, and the permanent magnet 25 as the third permanent magnet.

[0118] The permanent magnet 23 has a magnetic pole face 23a on the outer periphery 10a side, a magnetic pole face 23b on the inner periphery 10b side, and end faces 23c on both circumferential ends. The permanent magnet 24 has a magnetic pole face 24a on the pole center side, a magnetic pole face 24b on the opposite side, and end faces 24c on both circumferential ends. The permanent magnet 25 has a magnetic pole face 25a on the pole center side, a magnetic pole face 25b on the opposite side, and end faces 25c on both circumferential ends.

[0119] The magnet insertion hole 11 has an outer edge 11a on the outer periphery 10a side and an inner edge 11b on the inner periphery 10b side. The outer edge 11a of the magnet insertion hole 11 is in contact with the magnetic pole faces 23a, 24a, 25a An inner edge 11b of the magnet insertion hole 11 faces the magnetic pole faces 23b, 24b, and 25b of the permanent magnets 23, 24, and 25. The magnet insertion hole 11 may be provided with a step portion for positioning the permanent magnets 23, 24, and 25.

[0120] A magnet pole P1 serving as a first magnetic pole is formed by the permanent magnets 23, 24, and 25 arranged in each magnet insertion hole 11. A virtual magnetic pole P2 serving as a second magnetic pole is formed between adjacent magnet poles P1.

[0121] The pole center line C1 is a straight line that passes through the axis Ax and the circumferential center of the magnet pole P1, i.e., the circumferential center of the magnet insertion hole 11. The pole center line C2 is a straight line that passes through the circumferential center of the virtual magnetic pole P2 and the axis Ax.

[0122] In the permanent magnet 24, a corner between the magnetic pole face 24a and the end face 24c away from the pole center line C1 is defined as a corner R1. In the permanent magnet 25, a corner between the magnetic pole face 25a and the end face 25c away from the pole center line C1 is defined as a corner R2. Both corners R1 and R2 of the permanent magnets 24 and 25 are located within the flux barrier 12.

[0123] Corner R1 faces outer periphery 10a of rotor core 10 and corresponds to the corner furthest from pole center line C1 on one side of pole center line C1. Corner R2 faces outer periphery 10a of rotor core 10 and corresponds to the corner furthest from pole center line C1 on the other side of pole center line C1.

[0124] The angle between a straight line L1 passing through the corner R1 of the permanent magnet 20 and the axis Ax and a straight line L2 passing through the corner R2 and the axis Ax is defined as an angle θm. This angle θm represents the range occupied by the permanent magnets 23, 24, and 25 in the circumferential direction in angle.

[0125] As in the first embodiment, the angle θm satisfies θm ≧ 360 / N. Because the angle θm is 360 / N [degrees] or more, the areas of the pole faces 23a, 24a, 25a of the permanent magnets 23, 24, 25 per unit length in the axial direction can be increased.

[0126] As in the first embodiment, slits 13 are formed on the outer periphery 10a side of magnet insertion hole 11. Also, angle θs of the inter-slit area and angle θv of virtual magnetic pole P2 are as described in the first embodiment.

[0127] Except for the above points, the rotor 1B of the second modification is configured similarly to the rotor 1 of the first embodiment.

[0128] Although an example in which magnet insertion hole 11 has a bathtub shape has been described here, three permanent magnets 23, 24, and 25 may be arranged in magnet insertion hole 11 that is linear.

[0129] Thus, according to the second modification, even in the rotor 1B in which three permanent magnets 23, 24, 25 are arranged in the magnet insertion hole 11, the area of ​​the magnetic pole faces 23a, 24a, 25a of the permanent magnets 23, 24, 25 per unit length in the axial direction can be increased by making the angle θm of the permanent magnets 23, 24, 25 equal to or greater than 360 / N [degrees]. This makes it possible to increase the output and improve the efficiency while suppressing an increase in the manufacturing cost of the electric motor 2.

[0130] Embodiment 2 Next, a description will be given of embodiment 2. Fig. 12 is a cross-sectional view showing a rotor 1C according to embodiment 2. In rotor 1C according to embodiment 2, the circumferential width of virtual magnetic pole P2 differs between the radially outer side and the radially inner side.

[0131] The rotor core 10 of the rotor 1C is formed with N / 2 magnet insertion holes 11. The shape of the magnet insertion holes 11 is as described in the first embodiment. One permanent magnet 20 is disposed in each magnet insertion hole 11. Flux barriers 12 are formed as gaps at both circumferential ends of each magnet insertion hole 11.

[0132] Fig. 13 is an enlarged view of a portion of the rotor 1C. As shown in Fig. 13, flux barriers 12 are formed on both sides of the virtual magnetic pole P2. The flux barriers 12 also define both circumferential ends of the virtual magnetic pole P2.

[0133] The flux barrier 12 has an outer edge 12a extending along the outer periphery 10a of the rotor core 10, a side edge 12b which is the edge on the virtual magnetic pole P2 side, and a base edge 12c extending between the side edge 12b and the step portion 11c.

[0134] Of the two flux barriers 12 adjacent to each other across the virtual magnetic pole P2, the point on the side edge 12b of one of the flux barriers 12 closest to the outer periphery 10a is designated as point R3. (or the first point) The point on the side edge 12b of the other flux barrier 12 closest to the outer periphery 10a is defined as point R4. (or the second point) Let us assume that.

[0135] The point on the side edge 12b of the flux barrier 12 that is closest to the inner circumference 10b is designated as point R7. (or the third point) The point on the side edge 12b of the other flux barrier 12 that is closest to the inner circumference 10b is defined as point R8. (or the fourth point) Let us assume that.

[0136] The circumferential distance between points R3 and R4 is distance E1. The circumferential distance between points R7 and R8 is distance E2. Distances E1 and E2 have a relationship of E1>E2. Distance E1 corresponds to the width of virtual magnetic pole P2 on the radial outside, and distance E2 corresponds to the width of virtual magnetic pole P2 on the radial inside. Therefore, the relationship E1>E2 means that the circumferential width of virtual magnetic pole P2 is wider on the radial outside than on the radial inside.

[0137] This can also be expressed as follows using angles centered on the axis Ax. As shown in Fig. 12, a straight line passing through point R3 and the axis Ax is defined as a straight line L3, and a straight line passing through point R4 and the axis Ax is defined as a straight line L4. The angle between the straight lines L3 and L4 is defined as an angle θv1. This angle θv1 corresponds to the above-mentioned distance E1.

[0138] Also, the straight line passing through point R7 and axis Ax is called straight line L7, and the straight line passing through point R8 and axis Ax is called straight line L8. The angle between straight line L7 and straight line L8 is called angle θv2. This angle θv2 corresponds to the above-mentioned distance E2.

[0139] Both the angle θv1 and the angle θv2 are less than 360 / N [degrees]. The angle θv1 and the angle θv2 have a relationship of θv1>θv2. This corresponds to the relationship of E1>E2 described above.

[0140] As described in the first embodiment, in order to increase the area of ​​the magnetic pole face 20a of the permanent magnet 20 per unit length in the axial direction, it is desirable to increase the angle θm occupied by the permanent magnet 20. On the other hand, when the angle θm is increased, the difference in width between the N pole and the S pole on the surface of the rotor 1C increases.

[0141] In the second embodiment, distance E1, which is the radially outer width of virtual magnetic pole P2, is greater than distance E2, which is the radially inner width. By making distance E1 larger, the widths of the N pole and S pole on the surface of rotor 1C can be made closer to equal. Also, by making distance E2 smaller, the width of permanent magnet 20 can be made wider.

[0142] The slits 13 and the inter-slit areas between the magnet insertion holes 11 and the outer periphery 10a of the rotor core 10 are as described in the first embodiment. It is desirable that the angle θs of the inter-slit area is equal to or larger than the angle θv1, that is, θv1≦θs. This reduces the difference in width between the N poles and S poles on the surface of the rotor 1C, and also reduces vibrations caused by differences in magnetic attraction force.

[0143] The rotor 1C of the second embodiment is configured similarly to the rotor 1 of the first embodiment, except for the points mentioned above.

[0144] Note that, although an example in which one permanent magnet 20 is placed in each magnet insertion hole 11 has been described here, two or more permanent magnets may be placed in each magnet insertion hole 11 as described in variants 1 and 2.

[0145] As described above, according to the second embodiment, the circumferential distance between the flux barriers 12 on both sides of the virtual magnetic pole P2 is greater on the radially outer side than on the radially inner side. Therefore, the area of ​​the magnetic pole faces 20a of the permanent magnets 20 can be increased to increase the magnetic force while reducing the difference in width between the N pole and the S pole on the surface of the rotor 1C. This makes it possible to increase the output and improve the efficiency while suppressing an increase in the manufacturing cost of the electric motor 2.

[0146] <Air conditioning equipment> Next, an air conditioner to which the electric motor 2 of each of the above-mentioned embodiments and modified examples can be applied will be described. Fig. 14(A) is a diagram showing the configuration of an air conditioner 500 to which the electric motor 2 of the first embodiment is applied. The air conditioner 500 includes an outdoor unit 501 and an indoor unit 502. The outdoor unit 501 and the indoor unit 502 are connected by a refrigerant pipe 503.

[0147] Outdoor unit 501 includes outdoor blower 510, which is, for example, a propeller fan, and indoor unit 502 includes indoor blower 520, which is, for example, a crossflow fan. Outdoor blower 510 has impeller 511 and electric motor 2A that drives it. Indoor blower 520 has impeller 521 and electric motor 2B that drives it. Both electric motors 2A and 2B are configured with electric motor 2 described in embodiment 1. Note that compressor 504 that compresses the refrigerant is also shown in FIG. 14(A).

[0148] 14(B) is a cross-sectional view of outdoor unit 501. Electric motor 2A is supported by frame 509 arranged in housing 508 of outdoor unit 501. Impeller 511 is attached to rotating shaft 40 of electric motor 2A via hub 512.

[0149] In outdoor blower 510, impeller 511 is rotated by motor 2A to blow air to the outside. During cooling operation of air conditioner 500, heat released when refrigerant compressed by compressor 504 is condensed in a condenser (not shown) is released to the outside by the air blown by outdoor blower 510.

[0150] In indoor blower 520 (FIG. 14(A)), impeller 521 is rotated by motor 2B to blow air into the room. During cooling operation of air conditioner 500, air from which heat has been removed when the refrigerant evaporates in an evaporator (not shown) is blown into the room by indoor blower 520.

[0151] Since the electric motors 2A and 2B are configured by the electric motor 2 of the first embodiment, higher output can be obtained. Therefore, the operation efficiency of the outdoor fan 510 and the indoor fan 520 can be improved.

[0152] The electric motors 2A and 2B are not limited to the electric motor 2 of the embodiment 1, but may include the electric motor of the embodiment 2 or each of the modified examples. In addition, the electric motors of each of the embodiments and each of the modified examples are used in both the outdoor blower 510 and the indoor blower 520 here, but may be used in only one of them.

[0153] The electric motor 2 described in each embodiment is not limited to being used in a blower, but may also be used in a compressor of an air conditioner, and may also be used in electrical equipment other than air conditioners, such as household electrical appliances, ventilation fans, machine tools, etc.

[0154] Although the preferred embodiments have been specifically described above, various improvements and modifications can be made to these embodiments. [Explanation of symbols]

[0155] 1,1A,1B,1C rotor, 2,2A,2B electric motor, 3 rotor, 5 stator, 6 molded stator, 10 rotor core, 10a outer circumference, 10b inner circumference, 11 magnet insertion hole, 12 flux barrier, 13 slit, 14 core area, 15 slit, 20 permanent magnet, 21,23 permanent magnet (first permanent magnet), 22,24 permanent magnet (second permanent magnet), 25 permanent magnet (third permanent magnet), 20a,21a,22a,23a,24a,25a magnetic pole surface, 20b,21b,22b,23b,24b,25b magnetic pole surface, 30 resin part, 40 rotating shaft, 50 stator core, 51 teeth, 52 yoke, 54 insulating part, 55 coil, 60 molded resin part, 500 air conditioner, 501 outdoor unit, 502 indoor unit, 510 outdoor blower, 511 impeller, 520 indoor blower, 521 impeller, Ax axis, C1, C2 pole center line, P1 magnet pole, P2 virtual magnetic pole, R1 corner (first corner), R2 corner (second corner), R3 end (third corner), Point: First point ), R4 corner (fourth Point: Second point ), R5 end (No. 5 of point ), R6 end (No. 6 of point ), R7 point (third point), R8 Point (4th point) .

Claims

1. A rotor having N / 2 magnet poles (N is an even number) and N / 2 virtual poles, A rotor core is annular and has an axis as its center, and a plurality of permanent magnets are attached to the rotor core. Each of the N / 2 magnet poles is formed by at least one permanent magnet among the plurality of permanent magnets, and each of the N / 2 virtual magnetic poles is formed by a portion of the rotor core; a pole center line of each magnet pole is defined by a straight line passing through a center of the magnet pole in the circumferential direction of the rotor core and the axis line, The at least one permanent magnet forming the magnet pole has a first corner portion facing the outer periphery of the rotor core and furthest from the pole center line on one side of the pole center line, and a second corner portion facing the outer periphery and furthest from the pole center line on the other side of the pole center line, The rotor core has each magnet pole having: a magnet insertion hole in which the at least one permanent magnet is disposed; a non-magnetic portion that is formed between the magnet insertion hole and the outer periphery of the rotor core and extends in the circumferential direction; having a first gap and a second gap are formed at each end of two magnet insertion holes adjacent to each virtual magnetic pole, the first gap and the second gap being formed at each end of the two magnet insertion holes adjacent to each virtual magnetic pole; an angle θm between a line passing through the first corner portion and the axis and a line passing through the second corner portion and the axis satisfies θm≧360 / N [degrees]; a point in the first gap that faces the second gap and is closest to the outer periphery is defined as a first point; a point in the second gap that faces the first gap and is closest to the outer periphery is defined as a second point; a third point is a point in the first gap that faces the second gap and is closest to an inner circumference of the rotor core; If a point in the second gap that faces the first gap and is closest to the inner circumference is defined as a fourth point, An angle θv1 between a line passing through the first point and the axis and a line passing through the second point and the axis, and an angle θv2 between a line passing through the third point and the axis and a line passing through the fourth point and the axis satisfy θv1>θv2. Rotor.

2. The non-magnetic portion is formed continuously with the magnet insertion hole. The rotor of claim 1 .

3. the rotor core has a core region between the nonmagnetic portion and the magnet insertion hole in a radial direction about the axis, The radial width of the core region increases as it approaches the pole centerline. A rotor according to claim 1 or 2.

4. the non-magnetic portion is a first non-magnetic portion, and the rotor core has a second non-magnetic portion on the opposite side to the first non-magnetic portion across the pole center line; a fifth point is a point in the first nonmagnetic portion that is closest to the pole center line and to the outer periphery; If a point in the second nonmagnetic portion that is closest to the pole center line and closest to the outer periphery is defined as a sixth point, An angle θs between a line passing through the fifth point and the axis and a line passing through the sixth point and the axis satisfies θs≦360 / N [degrees]. A rotor according to any one of claims 1 to 3.

5. The angle θv1 satisfies θv1≦θs. A rotor according to claim 4.

6. The at least one permanent magnet forming each magnetic pole has a first permanent magnet and a second permanent magnet arranged on either side of the pole center line. A rotor according to any one of claims 1 to 5.

7. The at least one permanent magnet forming each magnetic pole includes a first permanent magnet arranged on the pole centerline, and a second permanent magnet and a third permanent magnet arranged on both sides of the first permanent magnet in the circumferential direction. A rotor according to any one of claims 1 to 5.

8. The angle θm satisfies θm<720 / N [degrees]. A rotor according to any one of claims 1 to 7.

9. A rotating shaft having the axis as a central axis; a non-magnetic resin portion that connects the rotating shaft and the rotor core; A rotor according to any one of claims 1 to 8.

10. A rotor according to any one of claims 1 to 9; A stator surrounding the rotor; An electric motor having

11. An electric motor according to claim 10; an impeller rotated by the electric motor; A blower equipped with

12. The system includes an outdoor unit and an indoor unit, At least one of the outdoor unit and the indoor unit has the blower according to claim 11. Air conditioning units.

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