WO2022215149A1 - Rotor, electric motor, blower, and air conditioning device - Google Patents

Abstract

This rotor (1) has a first permanent magnet (20) that has a rotating shaft (10), a magnet main body (21) supported by the rotating shaft (10), and a plurality of grooves (22) provided so as to be arranged at equal intervals in a circumferential direction about the rotating shaft (10) on a first outer circumferential surface (21c) that is a radially outward surface of the magnet main body (21), and a plurality of second permanent magnets (31) that have a stronger magnetic pole than that of the first permanent magnet (20) and are respectively disposed in the plurality of grooves (22). A first distance (OD1) that is the maximum distance between the first outer circumferential surface (21c) and the rotating shaft (10) is greater than a second distance (OD2) that is the maximum distance between the rotating shaft (10) and a second outer circumferential surface (31c) that is a radially outward surface of each second permanent magnet (31) of the plurality of second permanent magnets (31).

Description

Rotors, electric motors, blowers and air conditioners

The present disclosure relates to rotors, electric motors, fans, and air conditioners.

In a rotor used for an electric motor, there is known a configuration in which the rotor main body supported by the rotating shaft has two types of permanent magnets with different magnetic properties. See, for example, Patent Documents 1-3.

The rotors described in Patent Documents 1 and 2 have ferrite bond magnets and rare earth bond magnets arranged outside the ferrite bond magnets. The shape of the bonded rare earth magnets of Patent Documents 1 and 2 when viewed in the axial direction is annular.

The rotor described in Patent Document 3 has a ferrite bond magnet and a plurality of rare earth bond magnets supported by the ferrite bond magnet and arranged in the circumferential direction. Therefore, the cost of the rotor of Patent Document 3 is lower than that of the rotors of Patent Documents 1 and 2.

JP 2005-151757 A JP 2011-87393 A JP 2007-208104 A

However, in the rotor described in Patent Document 3, changes in the surface magnetic flux density are uneven. Specifically, in the rotor of Patent Document 3, since the magnetic force of the ferrite bonded magnet is weaker than the magnetic force of the rare earth bonded magnet, the distribution of the surface magnetic flux density in the rotor does not have a uniform sinusoidal waveform. Therefore, there is a problem that the effective magnetic flux interlinking with the stator core is distorted.

The present disclosure aims to prevent the occurrence of distortion of the effective magnetic flux.

A rotor according to an aspect of the present disclosure includes a rotating shaft, a magnet main body portion supported by the rotating shaft, and a first outer peripheral surface that is a radially outward surface of the magnet main body portion. A first permanent magnet having a plurality of grooves provided so as to be arranged at equal intervals in a circumferential direction centered on a magnetic pole stronger than the magnetic pole of the first permanent magnet, and a plurality of second permanent magnets arranged, wherein a first distance, which is a maximum distance between the first outer peripheral surface and the rotation axis, is determined for each of the plurality of second permanent magnets. It is longer than a second distance, which is the maximum distance between the second outer peripheral surface, which is the radially outward surface of the two permanent magnets, and the rotating shaft.

According to the present disclosure, it is possible to reduce the occurrence of distortion of the effective magnetic flux.

1 is a plan view showing a configuration of an electric motor according to Embodiment 1; FIG. FIG. 2 is a partial cross-sectional view showing the configuration of the electric motor shown in FIG. 1; FIG. 2 is a plan view showing the configuration of the rotor shown in FIG. 1; FIG. 4 is a cross-sectional view showing the configuration of the rotor shown in FIG. 3; FIG. 4 is a plan view showing the configuration of ferrite bond magnets of the rotor shown in FIG. 3; 8A is a plan view showing the configuration of a rotor according to Comparative Example 1. FIG. (B) is a side view showing a configuration of a rotor according to Comparative Example 1; (A) is a plan view showing a configuration of a rotor according to Comparative Example 2. FIG. (B) is a side view showing the configuration of a rotor according to Comparative Example 2. FIG. 7 is a graph showing the distribution of the surface magnetic flux density of the rotor according to Comparative Example 1 and the distribution of the surface magnetic flux density of the rotor according to Comparative Example 2; FIG. 4 is an enlarged plan view showing part of the configuration of the rotor shown in FIG. 3; FIG. 10 is an enlarged plan view showing the configuration of the rare earth bonded magnet shown in FIG. 9; FIG. 10 is a plan view showing a part of the rare earth bonded magnet and ferrite bonded magnet shown in FIG. 9; 4 is a flow chart showing a manufacturing process of the rotor according to Embodiment 1. FIG. 4 is a flow chart showing a manufacturing process of the rotor main body of the rotor according to Embodiment 1. FIG. FIG. 4 is a plan view showing a part of the configuration of a rotor according to a modified example of Embodiment 1; FIG. 8 is a plan view showing a part of the configuration of a rotor according to Embodiment 2; FIG. 11 is a plan view showing a part of the configuration of a rotor according to Embodiment 3; FIG. 11 is a plan view showing a part of the configuration of a rotor according to Embodiment 4; FIG. 11 is a plan view showing the configuration of a rotor according to Embodiment 5; FIG. 11 is a side view showing the configuration of a rotor according to Embodiment 5; FIG. 19 is a cross-sectional view of the rotor shown in FIG. 18 taken along line B20-B20; FIG. 11 is a plan view showing a configuration of a rotor according to a modified example of Embodiment 5; FIG. 22 is a cross-sectional view of the rotor shown in FIG. 21 taken along line B22-B22; FIG. 12 is a diagram schematically showing the configuration of a blower according to Embodiment 6; FIG. 11 is a diagram schematically showing the configuration of an air conditioner according to Embodiment 7;

A rotor, an electric motor, a fan, and an air conditioner according to embodiments of the present disclosure will be described below with reference to the drawings. The following embodiments are merely examples, and various modifications are possible within the scope of the present disclosure.

In order to make it easier to understand the relationship between drawings, each drawing may show an xyz orthogonal coordinate system. The z-axis is the coordinate axis parallel to the axis A of the rotor. The x-axis is a coordinate axis orthogonal to the z-axis. The y-axis is a coordinate axis orthogonal to both the x-axis and the z-axis.

<<Embodiment 1>>
FIG. 1 is a plan view showing the configuration of electric motor 100 according to Embodiment 1. FIG. FIG. 2 is a partial cross-sectional view showing the configuration of electric motor 100 shown in FIG. Electric motor 100 is, for example, a permanent magnet synchronous motor. Electric motor 100 has rotor 1 and stator 6 . The rotor 1 is arranged inside the stator 6 . That is, the electric motor 100 is an inner rotor type electric motor. An air gap G is formed between the rotor 1 and the stator 6 . Air gap G is, for example, a gap of 0.5 mm.

The rotor 1 has a shaft 10 as a rotating shaft. The shaft 10 extends in the z-axis direction. In the following description, the z-axis direction is also referred to as the "axial direction". Also, the direction along the circumference of a circle centered on the axis A of the shaft 10 is called the "circumferential direction C", and the direction of a straight line passing through the axis A perpendicular to the z-axis direction is called the "radial direction".

<stator>
The stator 6 has a stator core 61 and coils 62 wound around the stator core 61 . The stator core 61 has an annular yoke 61a centered on the axis A and a plurality of teeth 61b extending radially inward from the yoke 61a. The plurality of teeth 61b are arranged in the circumferential direction C at equal angular intervals. The teeth 61b face the outer peripheral surface 1c of the rotor 1 with an air gap G therebetween. In FIG. 1, the number of teeth 61b is twelve, for example. Note that the number of teeth 61b is not limited to twelve, and may be set to any number of two or more.

<Rotor>
Next, the details of the configuration of the rotor 1 will be described. FIG. 3 is a plan view showing the configuration of rotor 1 shown in FIG. FIG. 4 is a cross-sectional view showing the configuration of rotor 1 shown in FIG. As shown in FIGS. 2-4, the rotor 1 has a shaft 10, ferrite bonded magnets 20 as first permanent magnets, and a plurality of rare earth bonded magnets 31 as a plurality of second permanent magnets. . A rotor main body 50 supported by the shaft 10 is configured by the ferrite bond magnet 20 and the plurality of rare earth bond magnets 31 .

As shown in FIG. 2, in Embodiment ₁ , the length L1 of the rotor main body 50 in the z-axis direction is longer than the length L6 of the stator core 61 of the stator ₆ in the z-axis direction. As a result, the amount of effective magnetic flux interlinking with the stator core 61 of the stator 6 from the bond magnets (that is, the ferrite bond magnets 20 and the rare earth bond magnets 31) forming the rotor main body 50 can be increased. Note that the length L1 may be the _same as the length _L6 .

The ferrite bond magnet 20 includes a ferrite magnet and resin. The resin contained in the ferrite bond magnet 20 is, for example, nylon resin, PPS (Poly Phenylene Sulfide) resin, epoxy resin, or the like.

The rare earth bonded magnet 31 includes a rare earth magnet and resin. Rare earth magnets are, for example, neodymium magnets containing neodymium (Nd), iron (Fe) and boron (B), or samarium iron nitrogen magnets containing samarium (Sm), Fe and nitrogen (N). The resin contained in rare earth bonded magnet 31 is the same as the resin contained in ferrite bonded magnet 20, such as nylon resin, PPS resin, or epoxy resin.

The magnetic pole strength (that is, the amount of magnetism) of the rare earth bonded magnet 31 is different from the magnetic pole strength of the ferrite bonded magnet 20 . Specifically, rare earth bonded magnet 31 has a magnetic pole stronger than the magnetic pole of ferrite bonded magnet 20 . In other words, the magnetic force of rare earth bonded magnet 31 is greater than the magnetic force of ferrite bonded magnet 20 . Also, the coefficient of linear expansion of rare earth bonded magnet 31 is different from the coefficient of linear expansion of ferrite bonded magnet 20 .

As shown in FIG. 3, the ferrite bond magnet 20 is supported by the shaft 10 with the resin portion 7 interposed. The resin portion 7 has an inner tubular portion 71 , an outer tubular portion 72 , and a plurality of (for example, four) ribs 73 . The inner cylindrical portion 71 has a cylindrical shape and is fixed to the outer peripheral surface 10 a of the shaft 10 . The outer cylindrical portion 72 has a cylindrical shape and is fixed to the inner peripheral surface 20 b of the ferrite bond magnet 20 . A plurality of ribs 73 connect the inner tubular portion 71 and the outer tubular portion 72 . The plurality of ribs 73 radially extend radially outward from the outer periphery of the inner cylindrical portion 71 . The plurality of ribs 73 are arranged at equiangular positions in the circumferential direction C, for example. The resin portion 7 is made of, for example, unsaturated polyester resin. Note that the ferrite bond magnet 20 may be directly fixed to the shaft 10 without interposing the resin portion 7 .

FIG. 5 is a plan view showing the configuration of the ferrite bond magnet 20 shown in FIG. As shown in FIG. 5, the planar shape of the ferrite bonded magnet 20 parallel to the xy plane is an annular shape with the axis A as the center. The outer peripheral surface of the ferrite bond magnet 20 (that is, the outer peripheral surface 21c of the magnet main body 21 to be described later) forms a part of the outer peripheral surface 1c of the rotor 1 (see FIG. 1).

The ferrite bond magnet 20 has a cylindrical magnet main body 21 and a plurality of (for example, eight) grooves 22 . Magnet main body 21 is a portion of ferrite bond magnet 20 that is supported by shaft 10 (see FIG. 1). A plurality of grooves 22 are formed in an outer peripheral surface 21 c as a first outer peripheral surface of the magnet main body 21 . The outer peripheral surface 21 c is a radially outward surface of the magnet body portion 21 .

The groove portion 22 is a long groove elongated in the z-axis direction. The plurality of grooves 22 are arranged at regular intervals in the circumferential direction C. As shown in FIG. In the example shown in FIG. 5, the plurality of grooves 22 are arranged in the circumferential direction C at regular intervals. A plurality of rare earth bonded magnets 31 (see FIG. 3) are arranged in the plurality of grooves 22, respectively.

The ferrite bond magnet 20 is oriented so as to have polar anisotropy. As a result, the two grooves 22 adjacent in the circumferential direction C have magnetic poles with different polarities. In other words, in the circumferential direction C, the N-pole grooves 22 and the S-pole grooves 22 are alternately arranged. A magnetic flux (not shown) that has flowed in from the radially outer side of the S-pole groove portion 22 proceeds to the adjacent N-pole groove portion 22 in the circumferential direction C. As shown in FIG. Therefore, the rotor 1 (see FIG. 3) does not require a rotor core forming a magnetic path inside the ferrite bond magnets 20 in the radial direction. As a result, the number of parts in the rotor 1 can be reduced, and the weight of the rotor 1 can be reduced.

Returning to FIG. 3, the configuration of the rare earth bonded magnet 31 will be described. The plurality of rare earth bonded magnets 31 are arranged in the circumferential direction C at intervals. In the example shown in FIG. 3, a plurality of rare earth bonded magnets 31 are arranged in the circumferential direction C at equal intervals. An outer peripheral surface 31c as a second outer peripheral surface of the rare earth bonded magnet 31 forms a part of the outer peripheral surface 1c of the rotor 1 (see FIG. 1). The outer peripheral surface 31 c is a radially outward surface of the bonded rare earth magnet 31 .

Each of the plurality of rare earth bonded magnets 31 is oriented to have polar anisotropy. A plurality of rare earth bonded magnets 31 adjacent in the circumferential direction C have magnetic poles with different polarities. Circular arrow F shown in FIG. 3 indicates the direction of magnetic flux in rare earth bonded magnet 31 . The magnetic flux flowing from the radially outer side of the south pole rare earth bonded magnet 31 advances to the adjacent north pole rare earth bonded magnet 31 in the circumferential direction C. As shown in FIG. In Embodiment 1, since rare earth bonded magnets 31 have eight rare earth bonded magnets 31, rotor 1 has eight magnetic poles. The center of the rare earth bonded magnet 31 in the circumferential direction C is the pole center of the rotor 1 . Note that the number of poles of the rotor 1 is not limited to eight, and may be 2n or more. Here, n is a natural number of 1 or more.

The rare earth bonded magnet 31 is joined to the ferrite bonded magnet 20 . In Embodiment 1, rare earth bonded magnet 31 is joined to groove 22 of ferrite bonded magnet 20 by integrally molding (also referred to as “two-color molding”) ferrite bonded magnet 20 and rare earth bonded magnet 31 . Further, in Embodiment 1, rare earth bonded magnet 31 is filled in groove portion 22 .

In the following description, integral molding of the ferrite bonded magnet 20 and the rare earth bonded magnet 31 means that the rare earth bonded magnet 31 is molded while the previously manufactured ferrite bonded magnet 20 is placed in a mold. Thus, in comparison with the manufacturing process of molding ferrite bonded magnet 20 in a state in which a plurality of rare earth bonded magnets 31 manufactured in advance are arranged in a mold, in the first embodiment, a plurality of rare earth bonded magnets 31 are arranged one by one. The work of arranging it in the mold becomes unnecessary. Therefore, productivity of the rotor main body 50 can be improved.

Next, the cost of the rotor 1 according to Embodiment 1 will be explained in comparison with the rotor 101a according to Comparative Example 1. FIG. 6A is a plan view showing the configuration of a rotor 101a according to Comparative Example 1. FIG. FIG. 6B is a side view showing the configuration of the rotor 101a according to Comparative Example 1. FIG. 6A and 6B, illustration of the shaft 10 is omitted.

As shown in FIGS. 6A and 6B, in the rotor 101a, an annular rare earth bonded magnet 130a is arranged on the outer peripheral surface 120c of the annular ferrite bonded magnet 120a. That is, in rotor 101a, all of outer peripheral surface 101c of rotor 101a is formed of rare earth bonded magnet 130a.

On the other hand, as shown in FIG. 2 described above, in Embodiment 1, the outer peripheral surface 1c of the rotor 1 includes the outer peripheral surface 20c of the ferrite bonded magnet 20 and the outer peripheral surface 31c of each of the plurality of rare earth bonded magnets 31. formed by As a result, in the rotor 1, the amount of rare earth bonded magnets 31 used can be reduced compared to the rotor 101a. Specifically, in rotor 1, the amount of rare earth bonded magnets 31 used can be reduced by about 20% compared to rotor 101a.

Also, the rare earth bonded magnet 31 is more expensive than the ferrite bonded magnet 20 . For example, the material unit price of the rare earth bonded magnet 31 is ten times or more the material unit price of the ferrite bonded magnet 20 . Therefore, the outer peripheral surface 1c of the rotor 1 is formed by the outer peripheral surface 21c of the magnet main body 21 of the ferrite bonded magnet 20 and the outer peripheral surface 31c of the rare earth bonded magnet 31, thereby reducing the usage of the rare earth bonded magnet 31. can do. Therefore, the cost of the rotor 1 can be reduced.

Next, the surface magnetic flux density of the rotor 1 according to Embodiment 1 will be described in comparison with the rotor 101a according to Comparative Example 1 and the rotor 101b according to Comparative Example 2. FIG. 7A is a plan view showing the configuration of a rotor 101b according to Comparative Example 2. FIG. FIG. 7B is a side view showing the configuration of a rotor 101b according to Comparative Example 2. FIG. 7A and 7B, illustration of the shaft 10 is omitted.

As shown in FIGS. 7A and 7B, the rotor 101b has a ferrite bond magnet 120b and a plurality of rare earth bond magnets 131b. The plurality of rare earth bonded magnets 131b are arranged in the circumferential direction C at intervals. Therefore, the usage of rare earth bonded magnets 131b of rotor 101b is different from the usage of rare earth bonded magnets 130a of rotor 101a.

FIG. 8 is a graph showing the distribution of the surface magnetic flux density of the rotor 101a according to Comparative Example 1 and the distribution of the surface magnetic flux density of the rotor 101b according to Comparative Example 2. In FIG. 8, the horizontal axis indicates the position [degrees] in the circumferential direction C on the outer peripheral surface 101c of the rotor 101a or the outer peripheral surface 101d of the rotor 101b, and the vertical axis indicates the surface magnetic flux density [a. u. ] is shown. 8, the dashed line indicates the distribution of the surface magnetic flux density of the rotor 101a according to Comparative Example 1, and the solid line indicates the distribution of the surface magnetic flux density of the rotor 101b according to the second comparative example.

In FIG. 8, the distribution of the surface magnetic flux density of the rotor 101a is represented by the waveform S1, and the distribution of the surface magnetic flux density of the rotor 101b is represented by the waveform S2. The waveform S1 is represented by a sinusoidal waveform. In other words, in the rotor 101a, the change in surface magnetic flux density in the circumferential direction C is uniform. On the other hand, the waveform S2 is less smooth than the waveform S1. In other words, in the rotor 101b, changes in the surface magnetic flux density in the circumferential direction C are uneven.

Specifically, distortion occurs in a portion of the waveform S2 that corresponds to the interpolar portion of the rotor 1 . A pole-to-pole portion of the rotor 1 is a boundary between the north pole and the south pole. In Embodiment 1, the pole-to-pole portion of rotor 1 is portion 21e (see FIG. 5) between two rare earth bonded magnets 31 adjacent in circumferential direction C in magnet body portion 21 of ferrite bonded magnet 20. . When the distribution of the surface magnetic flux density is represented by the waveform S2, there is a problem that the effective magnetic flux interlinking with the stator core 61 (see FIG. 2) is distorted.

The rotor 1 according to Embodiment 1 has ferrite bond magnets 20 and a plurality of rare earth bond magnets 31 arranged at intervals in the circumferential direction C, like the rotor 101b according to Comparative Example 2. However, in Embodiment 1, the distortion of the effective magnetic flux can be reduced by the configuration described below.

FIG. 9 is a plan view showing a part of the configuration of rotor 1 according to the first embodiment. In FIG. 9, the first distance between point P1 on outer peripheral surface 21c of ferrite bond magnet 20 and axis A of shaft 10 is distance OD1. Distance OD1 is the maximum distance between outer peripheral surface 21c of ferrite bond magnet 20 and axis A. As shown in FIG. A second distance between point P2 on outer peripheral surface 31c of rare earth bonded magnet 31 and axis A is defined as distance OD2. Distance OD2 is the maximum distance between outer peripheral surface 31c of rare earth bonded magnet 31 and axis A. As shown in FIG. Distance OD1 is longer than distance OD2. That is, the distance OD1 and the distance OD2 satisfy the following formula (1).
OD1>OD2 (1)

The air gap G (see FIG. 1) between the outer peripheral surface 21c of the ferrite bond magnet 20 and the stator core 61 can be narrowed by the distance OD1 and the distance OD2 satisfying formula (1). As a result, the amount of effective magnetic flux interlinking with the stator core 61 increases. Therefore, the distortion of the effective magnetic flux in the interpolar portion of the rotor 1 can be reduced.

Further, the groove portion 22 of the ferrite bond magnet 20 has a bottom surface 22a, a first side surface 22b, and a second side surface 22c. The bottom surface 22a is a surface facing radially outward. The first side surface 22b and the second side surface 22c extend radially outward from both widthwise ends of the bottom surface 22a.

In the example shown in FIG. 9, the first side surface 22b and the second side surface 22c extend radially outward from both ends in the width direction of the bottom surface 22a so that the width of the groove 22 is narrowed. This prevents the rare-earth bonded magnets 31 placed in the grooves 22 from coming off due to interface peeling due to expansion or contraction due to temperature changes, or centrifugal force acting on the rotor 1 .

The outer peripheral surface 21c of the magnet main body 21 is composed of a plurality of connecting surfaces 21d. 21 d of connection surfaces are surfaces which connect the 1st side surface 22b of one groove part 22 and the 2nd side surface 22c of the other groove part 22 among the two groove parts 22 adjacent to the circumferential direction C. FIG. As described above, the distance OD1 and the distance OD2 satisfy the formula (1), so that the connecting surface 21d is located radially outside the outer peripheral surface 31c of the rare earth bonded magnet 31. As shown in FIG.

Next, the shape of rare earth bonded magnet 31 will be described. FIG. 10 is an enlarged plan view showing the configuration of rare earth bonded magnet 31 shown in FIG. In FIG. 10, the radial thickness at the central portion in the circumferential direction C of the rare earth bonded magnet 31 is t ₁ , and the radial thickness at the end portion in the circumferential direction C is t ₂ . An end portion of the rare earth bonded magnet 31 in the circumferential direction C is a boundary portion between the rare earth bonded magnet 31 and the magnet main body portion 21 . Thickness t1 is _{thicker than} thickness t2. That is, the thickness t1 and the thickness t2 satisfy the following _formula ( ₂ ).
t ₁ >t ₂ (2)

In this way, the radial thickness of the rare earth bonded magnet 31 becomes thinner from the center in the circumferential direction C toward the ends. As a result, the magnetic force of the rare-earth bonded magnet 31 can be weakened at the boundary between the rare-earth bonded magnet 31 and the magnet main body 21 while ensuring a sufficient amount of effective magnetic flux at the pole center portion of the rotor 1 . Therefore, the difference between the magnetic force at the end of the rare earth bonded magnet 31 in the circumferential direction C and the magnetic force at the interpolar portion of the rotor 1 can be reduced while suppressing the amount of the expensive rare earth bonded magnet 31 used.

In addition, the width W1 in the circumferential direction C of the outer peripheral surface 31c of the rare earth bonded magnet 31 is narrower _than the width W2 in the circumferential direction _C of the inner peripheral surface 31d of the rare earth bonded magnet 31, which is the radially inward surface. That is, the width W1 and the width W2 satisfy the following _formula ( ₃ ).
W2> _W1 ( ₃ )

_When the width W1 and the width W2 satisfy the expression ( ₃ ), the thickness t2 at the ends in the circumferential direction _C of the rare earth bonded magnet 31 can be made thinner _than the thickness t1 at the central portion in the circumferential direction C. . Therefore, the amount of expensive rare earth bonded magnet 31 used can be suppressed. In addition, when the width W1 and the width W2 satisfy the expression _{( 3} ), the rare earth bonded magnet 31 is prevented from interfacial peeling due to expansion or contraction due to temperature change, or centrifugal force acting on the rotor 1. 9) can be prevented from falling off.

FIG. 11 is an enlarged plan view showing a part of the configuration of rare earth bonded magnet 31 and ferrite bonded magnet 20 shown in FIG. In FIG. 11, the first point on the central portion of the inner peripheral surface 31d of the rare earth bonded magnet 31 in the circumferential direction C is the point Q ₁ , and the second point on the end portion of the inner peripheral surface 31d in the circumferential direction C is the point Q 1 . Let _Q2 . When the distance between the point _Q1 and the axis A is r3 _, and the distance between the point _Q2 and the axis A is _{r4 ,} the distance r3 is shorter than the distance _r4 . That is, the distance r ₃ and the distance r ₄ satisfy the following equation (4).
r ₃ <r ₄ (4)

When the distance r3 and the distance _r4 satisfy formula ( ₄ ), the thickness t2 at the end in the circumferential direction _C of the rare earth bonded magnet 31 can be made thinner _than the thickness t1 at the center in the circumferential direction C. . Therefore, the difference between the magnetic force at the end of the rare earth bonded magnet 31 in the circumferential direction C and the magnetic force at the interpolar portion of the rotor 1 can be reduced while suppressing the amount of the expensive rare earth bonded magnet 31 used.

Further, the outer peripheral surface 31c of the rare earth bonded magnet 31 also has a smaller diameter from the central portion toward the end portions in the circumferential direction C while ensuring the distance OD2. As a result, the air gap G (see FIG. 1) between the rare earth bonded magnet 31 and the stator 6 gradually widens from the pole center to the magnet boundary. Therefore, the difference between the magnetic force at the end of the rare earth bonded magnet 31 in the circumferential direction C and the magnetic force at the interpolar portion of the rotor 1 can be reduced.

Next, a method for manufacturing the rotor 1 will be described using FIG. FIG. 12 is a flow chart showing the manufacturing process of the rotor 1. As shown in FIG. A magnetizer is used in the manufacturing process of the rotor 1 .

In step ST1, the rotor main body 50 is formed. Details of step ST1 will be described later.

In step ST2, the rotor main body 50 is connected to the shaft 10. In Embodiment 1, the rotor main body 50 and the shaft 10 are integrated via the resin portion 7 , so that the rotor main body 50 is connected to the shaft 10 .

In step ST3, for example, the rotor main body 50 is magnetized using a magnetizer. Specifically, the ferrite bonded magnet 20 and the rare earth bonded magnet 31 are magnetized so that the ferrite bonded magnet 20 and the rare earth bonded magnet 31 have polar anisotropy.

Next, the details of the step of forming the rotor main body 50 (that is, step ST1 shown in FIG. 12) will be described with reference to FIG. FIG. 13 is a flow chart showing the steps of forming the rotor body 50. As shown in FIG. In the step of forming the rotor main body 50, a first mold for molding the ferrite bonded magnets 20, a second mold for molding the rare earth bonded magnets 31, and magnets for orientation are used. .

In step ST11, the inside of the first mold for molding the ferrite bond magnet 20 is filled with the raw material of the ferrite bond magnet 20. The ferrite bond magnet 20 is molded by injection molding, for example. Note that the ferrite bond magnet 20 may be molded by other molding methods such as press molding instead of injection molding.

In step ST12, while orienting the ferrite bond magnet 20, the ferrite bond magnet 20 having a predetermined shape is molded. In step ST12, for example, using a magnet for orientation, a magnetic field having polar anisotropy is generated inside the first mold, and while the raw material of the ferrite bond magnet 20 is oriented, the ferrite bond magnet Mold 20. As a result, a ferrite bonded magnet 20 having polar anisotropy is formed.

In step ST13, the formed ferrite bond magnet 20 is cooled.

At step ST14, the ferrite bond magnet 20 is taken out from the first mold.

At step ST15, the ferrite bond magnet 20 taken out is demagnetized.

In step ST16, the ferrite bond magnet 20 is placed inside the second mold for injection molding the rare earth bond magnet 31.

In step ST17, the raw material of the rare earth bonded magnet 31 is filled into the groove 22 of the ferrite bonded magnet 20 placed in the second mold. Rare-earth bonded magnet 31 is formed by, for example, injection molding. Note that the rare earth bonded magnet 31 may be molded by other molding methods such as press molding instead of injection molding.

In step ST18, while orienting the raw material of rare earth bonded magnet 31, rare earth bonded magnet 31 having a predetermined shape is molded. In step ST18, for example, a magnetic field having polar anisotropy is generated inside the second mold using an orienting magnet, and while the raw material of the rare earth bonded magnet 31 is oriented, the rare earth bonded magnet 31 is molded. Thereby, the rotor main body 50 in which the ferrite bond magnet 20 and the plurality of rare earth bond magnets 31 are integrally formed is formed.

In step ST19, the rotor main body 50 formed in step ST18 is cooled.

At step ST20, the cooled rotor main body 50 is taken out from the second mold.

In step ST21, the rotor main body 50 taken out in step ST20 is demagnetized.

<Effect of Embodiment 1>
According to the first embodiment described above, the distance OD1 between the first point P1 on the outer peripheral surface 21c of the ferrite bonded magnet 20 and the axis A of the shaft 10 is equal to the distance OD1 on the outer peripheral surface 31c of the rare earth bonded magnet 31. is longer than the distance OD2 between the second point P2 of and the axis A. As a result, the air gap G between the ferrite bond magnet 20 and the stator 6 is narrowed, so that the amount of effective magnetic flux interlinking with the stator core 61 is increased. Therefore, the distortion of the effective magnetic flux in the interpolar portion of the rotor 1 can be reduced.

Further, according to Embodiment 1, the radial thickness of rare earth bonded magnet 31 becomes thinner from the central portion in circumferential direction C toward the end portions. As a result, the magnetic force of the rare-earth bonded magnet 31 can be weakened at the boundary between the rare-earth bonded magnet 31 and the magnet main body 21 while ensuring a sufficient amount of effective magnetic flux at the pole center portion of the rotor 1 . Therefore, the difference between the magnetic force at the end of the rare earth bonded magnet 31 in the circumferential direction C and the magnetic force at the interpolar portion of the rotor 1 can be reduced while suppressing the amount of the expensive rare earth bonded magnet 31 used.

Further, according to Embodiment ₁ , the distance r3 between the point _Q1 on the central portion of the inner peripheral surface 31d of the rare earth bonded magnet 31 in the circumferential direction C and the axis A is less than the distance _r4 between the point _Q2 on the end of C and the axis A; As a result, the thickness t ₂ at the ends in the circumferential direction C of the rare earth bonded magnet 31 can be made thinner than the thickness t ₁ at the central portion in the circumferential direction C.

Further, according to Embodiment 1, electric motor 100 has rotor 1 and stator 6 . As described above, in the rotor 1, it is possible to reduce the occurrence of distortion of the effective magnetic flux in the interpolar portion. Since the electric motor 100 has the rotor 1, it is possible to prevent the electric motor 100 from being vibrated and to prevent the output from being lowered.

<<Modification of Embodiment 1>>
FIG. 14 is a plan view showing a configuration of rotor 1A according to a modification of Embodiment 1. FIG. 14, the same or corresponding components as those shown in FIG. 9 are given the same reference numerals as those shown in FIG. A rotor 1A according to a modification of the first embodiment differs from the rotor 1 according to the first embodiment in the shape of ferrite bond magnets 20A. Other points are the same as the rotor 1 according to the first embodiment. Therefore, FIG. 3 will be referred to in the following description.

As shown in FIG. 14, the rotor 1A has a ferrite bond magnet 20A and a plurality of rare earth bond magnets 31A.

The ferrite bond magnet 20A has a magnet main body 21A supported by the shaft 10 (see FIG. 3) and a plurality of grooves 22. 21 A of magnet main-body parts have the connection surface 121d which connects the 1st side surface 22b of one groove part 22 and the 2nd side surface 22c of the other groove part 22 among the two groove parts 22 adjacent to the circumferential direction C. FIG.

In the example shown in FIG. 14, the width W1 of the outer peripheral surface 31c of the rare earth bonded magnet ₃₁ is wider _than the width W3 of the connecting surface 121d of the ferrite bonded magnet 20 in the circumferential direction C. As shown in FIG. That is _, the width W1 and the width W3 satisfy the following formula ( ₅ ).
W1>W3 _{( 5} )
As a result, the ratio of the rare earth bonded magnets 31 to the interpolar portion of the rotor 1A is increased, so that the decrease in the magnetic force in the interpolar portion can be suppressed.

In the example shown in FIG. 14, as in the _first embodiment, the width W1 of the outer peripheral surface 31c of the rare earth bonded magnet 31 in the circumferential direction C is equal to the width W1 of the inner peripheral surface 31d of the rare earth bonded magnet 31 in the circumferential direction C. Narrower _than W2. Therefore, in the example shown in FIG. 14, width W ₁ , width W ₂ and width W ₃ satisfy the following equation (6).
W2> _W1 >W3 _{( 6} )
As a result, it is possible to suppress the decrease in the magnetic force in the interpolar portion of the rotor 1A while suppressing the usage amount of the expensive rare earth bonded magnets 31 .

<Effects of Modification of Embodiment 1>
According to the modified example of Embodiment ₁ described above, the width W1 in the circumferential direction C of the outer peripheral surface 31c of the rare earth bonded magnet ₃₁ is greater than the width W3 in the circumferential direction C of the connecting surface 121d of the ferrite bonded magnet 20A. wide. As a result, the ratio of the rare earth bonded magnets 31 to the interpolar portion of the rotor 1A is increased, so that the decrease in the magnetic force in the interpolar portion can be suppressed.

<<Embodiment 2>>
FIG. 15 is a plan view showing part of the configuration of the rotor 2 according to the second embodiment. 15, the same or corresponding components as those shown in FIG. 9 are given the same reference numerals as those shown in FIG. Rotor 2 according to Embodiment 2 differs from rotor 1 according to Embodiment 1 in the shape of ferrite bond magnets 220 . Except for this point, the rotor 2 according to the second embodiment is the same as the rotor 1 according to the first embodiment. Therefore, FIG. 3 will be referred to in the following description.

As shown in FIG. 15, the rotor 2 has a ferrite bond magnet 220 and a plurality of rare earth bond magnets 31.

The ferrite bond magnet 220 has a magnet main body 221 supported by the shaft 10 (see FIG. 3) and a plurality of grooves 22 . Magnet main body 221 partially covers outer peripheral surface 31 c of rare earth bonded magnet 31 . Specifically, the magnet main body 221 covers the end in the circumferential direction C of the outer peripheral surface 31c. This prevents the rare earth bonded magnet 31 from falling off from the ferrite bonded magnet 220 due to interface separation due to expansion or contraction due to temperature change or centrifugal force acting on the rotor 2 .

In the example shown in FIG. 15 , the magnet main body 221 extends circumferentially from a plane V including the side surface of the groove 22 (specifically, one of the first side surface 22b and the second side surface 22c). It has an overhanging portion 221f that protrudes toward C. The projecting portion 221f is in contact with the end portion in the circumferential direction C of the outer peripheral surface 31c. Note that the magnet main body 221 may cover the entire outer peripheral surface 31 c of the rare earth bonded magnet 31 . That is, the magnet body 221 may cover at least a portion of the outer peripheral surface 31c.

<Effect of Embodiment 2>
According to the second embodiment described above, magnet main body 221 partially covers outer peripheral surface 31 c of rare earth bonded magnet 31 . This prevents the rare earth bonded magnet 31 from falling off from the ferrite bonded magnet 220 due to interface separation due to expansion or contraction due to temperature change or centrifugal force acting on the rotor 2 .

<<Embodiment 3>>
FIG. 16 is a plan view showing part of the configuration of the rotor 3 according to the third embodiment. 16, the same or corresponding components as those shown in FIG. 9 are given the same reference numerals as those shown in FIG. Rotor 3 according to Embodiment 3 differs from rotor 1 according to Embodiment 1 in the shape of ferrite bond magnets 320 . Except for this point, the rotor 3 according to the third embodiment is the same as the rotor 1 according to the first embodiment. 1 and 3 are therefore referred to in the following description.

As shown in FIG. 16, the rotor 3 has a ferrite bond magnet 320 and a plurality of rare earth bond magnets 31.

The ferrite bond magnet 320 has a magnet main body 321 supported by the shaft 10 (see FIG. 3) and a plurality of grooves 22 . The outer peripheral surface of the magnet body portion 321 is composed of a plurality of connecting surfaces 321d. 321 d of connection surfaces connect the 1st side surface 22b of one groove part 22 and the 2nd side surface 22c of the other groove part 22 among the two groove parts 22 which adjoin the circumferential direction C. As shown in FIG.

In FIG. 16, a point as a third point on the end portion of the connecting surface 321d in the circumferential direction C is designated as P5. A point P5 is a point located at the magnet boundary of the rotor 3 . The fourth point is a point on the central portion of the connecting surface 321d in the circumferential direction C, and the point is P6. A point P6 is a point positioned between poles of the rotor 3 . Also, the distance between the point P5 and the axis A is defined as a distance OD5, and the distance between the point P6 and the axis A is defined as a distance OD6. In the example shown in FIG. 16, distance OD5 is longer than distance OD6. That is, the distance OD5 and the distance OD6 satisfy the following formula (7).
OD5>OD6 (7)

Since the distance OD5 and the distance OD6 satisfy the expression (7), the air gap between the ferrite bond magnet 320 and the stator 6 (see FIG. 1) increases as the rotor 3 approaches the magnet boundary from the pole-to-pole portion. G gradually narrows. Therefore, it is possible to suppress the amount of ferrite bond magnet 320 used in the interpolar portion while increasing the amount of effective magnetic flux in the vicinity of the magnet boundary portion.

<Effect of Embodiment 3>
According to the third embodiment described above, the distance OD5 between the point P5 on the end portion of the connecting surface 321d in the circumferential direction C and the axis A is the point on the central portion of the connecting surface 321d in the circumferential direction C. longer than the distance OD6 between P6 and axis A; As a result, in the rotor 3 , the air gap G between the ferrite bond magnet 320 and the stator 6 gradually narrows from the interpolar portion to the magnet boundary portion. Therefore, it is possible to suppress the amount of ferrite bond magnet 320 used in the interpolar portion while increasing the amount of effective magnetic flux in the vicinity of the magnet boundary portion.

<<Embodiment 4>>
FIG. 17 is a plan view showing part of the configuration of the rotor 4 according to the fourth embodiment. 17, the same or corresponding components as those shown in FIG. 16 are given the same reference numerals as those shown in FIG. Rotor 4 according to the fourth embodiment differs from rotor 3 according to the third embodiment in the shape of ferrite bond magnets 420 . Except for this point, the rotor 4 according to the fourth embodiment is the same as the rotor 3 according to the third embodiment.

As shown in FIG. 17, the rotor 4 has a ferrite bond magnet 420 and a plurality of rare earth bond magnets 31.

The ferrite bond magnet 420 has a magnet main body 421 supported by the shaft 10 (see FIG. 3) and a plurality of grooves 22 . The outer peripheral surface of the magnet body portion 421 is composed of a plurality of connecting surfaces 421d.

The connecting surface 421d connects the first side surface 22b of one of the two grooves 22 adjacent in the circumferential direction C and the second side surface 22c of the other groove 22. When the magnet main body 421 is viewed in the z-axis direction, a portion 421g of the connecting surface 421d between the points P5 and P6 is a curved surface projecting outward in the radial direction. Thereby, the shape of the ferrite bond magnet 20 when viewed in the z-axis direction becomes a substantially petal shape. Also in this case, the air gap G between the ferrite bond magnet 420 and the stator 6 (see FIG. 1) gradually narrows from the pole-to-pole portion of the rotor 4 toward the magnet boundary portion. Therefore, it is possible to reduce the amount of ferrite bond magnets 420 used in the interpolar portion while increasing the amount of effective magnetic flux in the vicinity of the magnetic boundary portion of the rotor 4 . In the example shown in FIG. 17, the radius of curvature of the portion 421g between the points P5 and P6 of the connecting surface 421d near the point P6 is smaller than the radius of curvature of the outer peripheral surface 31c of the rare earth bonded magnet 31. In the example shown in FIG. That is, in the fourth embodiment, the radius of curvature of a portion of connecting surface 421 d is smaller than the radius of curvature of outer peripheral surface 31 c of rare earth bonded magnet 31 .

<Effect of Embodiment 4>
According to the fourth embodiment described above, the portion between the point P5 and the point P6 in the connecting surface 421d is a curved surface that projects outward in the radial direction. As a result, the air gap G (see FIG. 1) between the ferrite bond magnet 420 and the stator 6 can be gradually narrowed from the pole-to-pole portion of the rotor 4 toward the magnet boundary portion. Therefore, it is possible to reduce the amount of ferrite bond magnets 420 used in the interpolar portion while increasing the amount of effective magnetic flux in the vicinity of the magnetic boundary portion of the rotor 4 .

<<Embodiment 5>>
18 is a plan view showing the configuration of the rotor 5 according to Embodiment 5. FIG. 19 is a side view showing the configuration of the rotor 5 according to Embodiment 5. FIG. FIG. 20 is a cross-sectional view of the rotor 5 shown in FIG. 18 taken along line B20-B20. 18-20, components identical or corresponding to those shown in FIGS. 1-3 are labeled with the same reference numerals as those shown in FIGS. 1-3. A rotor 5 according to the fifth embodiment is different from the rotors 1 to 4 according to any one of the first to fourth embodiments in that it further has ring members 8 and 9 . 18 to 20, illustration of the shaft 10 and the resin portion 7 (see FIG. 3) is omitted.

As shown in FIGS. 18-20, the rotor 5 has a ferrite bond magnet 20, a plurality of rare earth bond magnets 31, and a plurality of ring members 8 and 9 as a plurality of first resin portions.

The ring members 8 and 9 are annular members centered on the axis A, respectively. The ring members 8 and 9 are made of resin such as unsaturated polyester resin, for example.

The ring member 8 is arranged to cover the +z-axis side end face 20j of the ferrite bond magnet 20 and the +z-axis side end face 31j of the rare earth bond magnet 31 . As a result, end surface 31 j of rare earth bonded magnet 31 is connected to end surface 20 j of ferrite bonded magnet 20 via ring member 8 . Therefore, peeling of the bonded rare earth magnet 31 due to temperature change can be further prevented.

In Embodiment 5, ring member 8 is fixed to ferrite bond magnet 20 and rare earth bond magnet 31 . Specifically, the ring member 8 is fixed to the +z-axis side end face 20j of the ferrite bond magnet 20 and the +z-axis side end face 31j of the rare earth bond magnet 31 .

The ring member 9 is arranged so as to cover the end face 20k of the ferrite bond magnet 20 on the -z axis side and the end face 31k of the rare earth bond magnet 31 on the -z axis side. As a result, end surface 31 k of rare earth bonded magnet 31 is connected to end surface 20 k of ferrite bonded magnet 20 via ring member 9 . As a result, peeling of the rare earth bonded magnet 31 due to temperature change can be further prevented.

In Embodiment 5, ring member 9 is fixed to ferrite bond magnet 20 and rare earth bond magnet 31 . Specifically, the ring member 9 is fixed to an end face 20k of the ferrite bond magnet 20 facing the -z-axis direction and an end face 31k of the rare earth bond magnet 31 facing the -z-axis direction. Note that the rotor 5 can be realized without having either one of the plurality of ring members 8 and 9 .

<Effect of Embodiment 5>
According to the fifth embodiment described above, rotor 5 has ring members 8 and 9 arranged to cover the end surfaces of ferrite bond magnet 20 and rare earth bond magnet 31 in the z-axis direction, respectively. As a result, rare earth bonded magnet 31 is connected to ferrite bonded magnet 20 via ring members 8 and 9 . Therefore, it is possible to further prevent the rare earth bonded magnet 31 from coming off due to the centrifugal force acting during rotation. Moreover, it is possible to further prevent peeling of the bonded rare earth magnet 31 due to temperature changes.

<<Modification of Embodiment 5>>
FIG. 21 is a plan view showing the configuration of a rotor 5A according to a modification of the fifth embodiment. FIG. 22 is a cross-sectional view of the rotor 5A shown in FIG. 21 taken along line B22-B22. A rotor 5A according to a modification of the fifth embodiment differs from the rotor 5 according to the fifth embodiment in that ring members 8A and 9A are integrally formed with a resin portion 7A.

As shown in FIGS. 20 and 21, the rotor 5A includes a shaft 10, ferrite bond magnets 20, a plurality of rare earth bond magnets 31, ring members 8A and 9A as first resin portions, and second and a resin portion 7A as a resin portion.

The resin portion 7A includes an inner cylinder portion 71 supported by the shaft 10, an outer cylinder portion 72A fixed to the inner peripheral surface 20b of the ferrite bond magnet 20, and a plurality of components connecting the inner cylinder portion 71 and the outer cylinder portion 72A. and ribs 73A.

The resin portion 7A is integrally formed with the ring members 8A and 9A. In other words, the resin portion 7A is connected to the ring members 8A and 9A. In the modification of Embodiment 5, the outer cylindrical portion 72A and ribs 73A of the resin portion 7A are connected to the ring members 8A and 9A. Therefore, in the modification of Embodiment 5, shaft 10, ferrite bond magnet 20 and rare earth bond magnet 31 are connected via resin portion 7A and ring members 8A and 9A. Thereby, when integrally molding the shaft 10 and the ferrite bond magnet 20 with the resin portion 7A interposed therebetween, the ring members 8A and 9A can also be molded at the same time. Therefore, the manufacturing process of the rotor 5A can be simplified.

<Effects of Modification of Embodiment 5>
According to the modified example of the fifth embodiment described above, in rotor 5A, resin portion 7A is integrally formed with ring members 8A and 9A. Thereby, when integrally molding the shaft 10 and the ferrite bond magnet 20 with the resin portion 7A interposed therebetween, the ring members 8A and 9A can also be molded at the same time. Therefore, the manufacturing process of the rotor 5A can be simplified.

Here, the natural frequency of the rotor 5A changes depending on the rigidity of the rotor 5A. The rigidity of the rotor 5A can be adjusted, for example, by changing the width in the circumferential direction C, the length in the radial direction, and the number of ribs 73A in the resin portion 7A. In the modification of Embodiment 5, the rib 73A of the resin portion 7A is connected to the ring members 8A and 9A by integrally forming the resin portion 7A with the ring members 8A and 9A. Thereby, the radial length of the rib 73A is increased. Thereby, the rigidity of the rotor 5A can be changed, and the natural frequency of the rotor 5A can be changed. Therefore, the occurrence of resonance can be suppressed, and the vibration characteristics of the rotor 5A can be adjusted to appropriate characteristics.

Also, the moment of inertia of the rotor 5A changes depending on the mass of the rotor 5A. The mass of the rotor 5A can be adjusted by changing the width in the circumferential direction C, the length in the radial direction, and the number of ribs 73A. As the moment of inertia increases, a greater starting torque is required, but the rotation of the rotor 5A can be stabilized. As described above, in the modified example of the fifth embodiment, the resin portion 7A is connected to the ring members 8 and 9, so the radial length of the rib 73A is increased. Thereby, the moment of inertia of the rotor 5A can be increased. Since the resin portion 7A is integrally formed with the ring members 8A and 9A in this manner, the natural frequency and moment of inertia of the rotor 5A can be adjusted to appropriate values.

<<Embodiment 6>>
Next, blower 600 having electric motor 100 according to Embodiment 1 will be described. FIG. 23 is a diagram schematically showing the configuration of blower 600 according to the sixth embodiment.

As shown in FIG. 23 , blower 600 has electric motor 100 and fan 601 as an impeller driven by electric motor 100 . Fan 601 is attached to the shaft of electric motor 100 . When the shaft of electric motor 100 rotates, fan 601 rotates and an airflow is generated. The blower 600 is used, for example, as an outdoor blower for an outdoor unit 720 of an air conditioner 700 shown in FIG. 24 which will be described later. In this case, fan 601 is, for example, a propeller fan.

<Effect of Embodiment 6>
According to the sixth embodiment described above, blower 600 has electric motor 100 described in the first embodiment. As described above, the reliability of the electric motor 100 according to Embodiment 1 is improved, so the reliability of the blower 600 including the electric motor 100 can also be improved.

<<Embodiment 7>>
Next, air conditioner 700 having fan 600 shown in FIG. 23 will be described. FIG. 24 is a diagram showing the configuration of an air conditioner 700 according to Embodiment 7. As shown in FIG.

As shown in FIG. 24, the air conditioner 700 has an indoor unit 710, an outdoor unit 720, and refrigerant pipes 730. The indoor unit 710 and the outdoor unit 720 are connected by a refrigerant pipe 730 to form a refrigerant circuit in which refrigerant circulates. The air conditioner 700 can operate, for example, a cooling operation in which cool air is blown from the indoor unit 710, or a heating operation in which warm air is blown.

The indoor unit 710 has an indoor fan 711 and a housing 712 that accommodates the indoor fan 711 . The indoor fan 711 has an electric motor 711a and a fan 711b driven by the electric motor 711a. The fan 711b is attached to the shaft of the electric motor 711a. Rotation of the shaft of the electric motor 711a rotates the fan 711b to generate airflow. Fan 711b is, for example, a cross-flow fan.

The outdoor unit 720 has a fan 600 as an outdoor fan, a compressor 721, and a housing 722 that accommodates the fan 600 and the compressor 721. The compressor 721 has a compression mechanism portion 721a that compresses refrigerant and an electric motor 721b that drives the compression mechanism portion 721a. The compression mechanism portion 721a and the electric motor 721b are connected to each other by a rotating shaft 721c. Note that the electric motor 100 according to the first embodiment may be used as the electric motor 721b of the compressor 721. FIG.

For example, when the air conditioner 700 is in cooling operation, the heat released when the refrigerant compressed by the compressor 721 is condensed by the condenser (not shown) is released to the outside by the blower 600. It should be noted that the fan 600 according to Embodiment 6 may be used not only as the outdoor fan of the outdoor unit 720 but also as the indoor fan 711 described above. In addition, the blower 600 may be provided not only in the air conditioner 700 but also in other devices.

The outdoor unit 720 further has a four-way valve (not shown) that switches the flow direction of the refrigerant. The four-way valve of the outdoor unit 720 allows the high-temperature, high-pressure refrigerant gas delivered from the compressor 721 to flow through the heat exchanger of the outdoor unit 720 during cooling operation, and through the heat exchanger of the indoor unit 710 during heating operation.

<Effect of Embodiment 7>
According to Embodiment 7 described above, air conditioner 700 has fan 600 . As described above, air blower 600 has improved reliability by including electric motor 100 described in Embodiment 1. Therefore, the reliability of air conditioner 700 can also be improved.

1, 1A, 2, 3, 4, 5, 5A rotor 6 stator 7 resin portion 8, 8A, 9, 9A ring member 10 shaft 20, 20A, 220, 320, 420 ferrite bond magnet, 20j, 20k, 31j, 31k end face 21 magnet main body 21c, 31c outer peripheral face 21d, 321d, 421d connecting face 22 groove 22a bottom face 22b first side face 22c second side face 31 rare earth bond magnet _, 100 Electric motor 600 _Blower 601 Fan 700 Air conditioner 710 Indoor unit 720 Outdoor unit , P6 points, t ₁ , t ₂ thicknesses, W ₁ , W ₂ , W ₃ widths.

Claims (16)

1. a rotating shaft;
   A magnet main body portion supported by the rotating shaft, and a first outer peripheral surface, which is a radially outward surface of the magnet main body portion, are provided so as to be arranged at equal intervals in a circumferential direction around the rotating shaft. a first permanent magnet having a plurality of grooves;
   a plurality of second permanent magnets having magnetic poles stronger than the magnetic poles of the first permanent magnets and arranged in the plurality of grooves;
   A first distance, which is the maximum distance between the first outer peripheral surface and the rotation axis, is the radially outward surface of each second permanent magnet of the plurality of second permanent magnets. A rotor longer than a second distance, which is the maximum distance between a second outer peripheral surface and the rotating shaft.
2. The rotor according to claim 1, wherein the thickness of the second permanent magnet in the radial direction becomes thinner from a central portion in the circumferential direction about the rotation axis toward an end portion in the circumferential direction.
3. The distance between a first point on the center portion in the circumferential direction of the inner peripheral surface of the second permanent magnet, which is the surface facing inward in the radial direction, and the rotation axis 3. The rotor according to claim 1 or 2, which is shorter than the distance between a second point on the circumferential edge of the surface of and the rotation axis.
4. The rotor according to claim 3, wherein the circumferential width of the second outer peripheral surface is narrower than the circumferential width of the inner peripheral surface.
5. The rotor according to any one of claims 1 to 4, wherein the magnet body portion covers at least part of the second outer peripheral surface.
6. Each groove of the plurality of grooves,
   a bottom surface, which is a surface facing outward in the radial direction of the first permanent magnet;
   first and second side surfaces extending outward in the radial direction from both ends of the bottom surface in the width direction;
   2. The magnet main body has a connecting surface that connects a first side surface of one of two grooves adjacent in a circumferential direction around the rotation axis and a second side surface of the other groove. Rotor as described.
7. The rotor according to claim 6, wherein the width of the connecting surface in the circumferential direction is longer than the width of the second outer circumferential surface in the circumferential direction.
8. A distance between a third point on the circumferential end portion of the connecting surface and the rotation axis is a distance between a fourth point on the circumferential center portion of the connection surface and the rotation axis. 8. The rotor according to claim 6 or 7, which is longer than the distance of .
9. a portion of the connection surface between the third point and the fourth point is a curved surface that is convex outward in the radial direction;
   The rotor according to claim 8, wherein the radius of curvature of the portion of the curved surface is smaller than the radius of curvature of the second outer peripheral surface.
10. 10. The rotation according to any one of claims 1 to 9, further comprising a first resin portion connected to an axial end face of each of said rotating shafts of said first permanent magnet and said second permanent magnet. Child.
11. further comprising a second resin portion connecting the rotating shaft and the first permanent magnet;
    The rotor according to claim 10, wherein the second resin portion is formed integrally with the first resin portion.
12. The first permanent magnet is a ferrite bond magnet,
    The rotor according to any one of claims 1 to 11, wherein the second permanent magnet is a rare earth bonded magnet.
13. The rotor is a rotor having 2n (n is a natural number equal to or greater than 1) magnetic poles,
    The rotor according to any one of claims 1 to 12, wherein each of said first permanent magnet and said second permanent magnet has polar anisotropy.
14. A rotor according to any one of claims 1 to 13;
    An electric motor having a stator and
15. an electric motor according to claim 14;
    and an impeller driven by the electric motor.
16. indoor unit and
    and an outdoor unit connected to the indoor unit,
    At least one of the indoor unit and the outdoor unit has the electric motor according to claim 14. An air conditioner.

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