WO2017163383A1

WO2017163383A1 - Permanent-magnet electric motor, compressor, and air-conditioner

Info

Publication number: WO2017163383A1
Application number: PCT/JP2016/059476
Authority: WO
Inventors: 馬場　和彦
Original assignee: 三菱電機株式会社
Priority date: 2016-03-24
Filing date: 2016-03-24
Publication date: 2017-09-28
Also published as: JPWO2017163383A1; JP6526315B2

Abstract

A rotor core 4 of the permanent-magnet electric motor has inner surfaces that form magnet holes for disposing permanent magnets 6 therein, and each of the inner surfaces has a first surface that is disposed on the outer side in a radial direction and second surface that is disposed on the inner side in the radial direction. The first surface has multiple grooves 9a1 through 9a5, and the second surface has multiple grooves 9b1 through 9b4. In addition, the permanent magnet 6 has a third surface that faces the first surface and a fourth surface that faces the second surface. The third surface has multiple portions 6a1 through 6a5 that are exposed to the multiple grooves 9a1 through 9a5. The fourth surface has multiple portions 6b1 through 6b4 that are exposed to the multiple grooves 9b1 through 9b4. In a cross-section of the rotor core 4 perpendicular to an axial direction, the total length of the multiple grooves 9a1 through 9a5 is longer than the total length of the multiple portions 6b1 through 6b4.

Description

Permanent magnet motor, compressor, and air conditioner

The present invention relates to a permanent magnet motor in which a permanent magnet is arranged inside a rotor core, a compressor including the permanent magnet motor, and an air conditioner including the compressor.

In general, in a permanent magnet motor, an eddy current is generated on the surface of the permanent magnet as the magnetic field due to the coil current of the stator fluctuates on the surface of the permanent magnet, and the heat generated by the eddy current increases the temperature of the permanent magnet. . Since permanent magnets are more likely to be demagnetized at higher temperatures, it has been a conventional problem to suppress the temperature rise of the permanent magnets.

In Patent Document 1, a rotor core of a permanent magnet motor is provided with a plurality of groove-shaped cooling channels extending in the axial direction on an inner peripheral side contact surface or an outer peripheral side contact surface with a permanent magnet in a magnet hole.

JP 2007-104888 A

In Patent Document 1, since the plurality of groove-shaped cooling channels are provided only on one of the inner peripheral side contact surface and the outer peripheral side contact surface, the cooling effect of the permanent magnet is limited. In order to improve the cooling effect, the width of the cooling channel may be enlarged, but the cooling channel suppresses the passage of the magnetic flux of the permanent magnet, so the magnetic flux of the permanent magnet cannot be used effectively, It may lead to a decrease in the efficiency of the motor.

The present invention has been made in view of the above, and suppresses a temperature increase of a permanent magnet due to an eddy current, can improve the demagnetization resistance of the permanent magnet, and can improve the efficiency of the electric motor. The purpose is to obtain an electric motor.

In order to solve the above-described problems and achieve the object, a permanent magnet motor according to the present invention includes an annular stator core, and a plurality of magnets arranged coaxially with the stator core inside the stator core. A first end surface, a second end surface, and a plurality of inner surfaces, wherein the first end surface and the second end surface are axially spaced from each other, and the plurality of inner surfaces are the plurality of the plurality of inner surfaces. A plurality of magnet holes arranged in a circumferential direction and extending in the axial direction from the first end surface to the second end surface; and disposed in the plurality of magnet holes. A plurality of permanent magnets, wherein each of the plurality of inner surfaces includes a first surface arranged on the outer side of the rotor core in a radial direction of the rotor core and the radial direction of the rotor core. And a second surface disposed inside Each of the plurality of permanent magnets has a third surface facing the first surface and a fourth surface facing the second surface, and the first surface is the first surface. A plurality of first grooves arranged along the third surface in a cross section of the rotor core extending in the axial direction from the end surface to the second end surface and perpendicular to the axial direction; 3 surface has a plurality of first portions exposed in the plurality of first grooves, and the third surface is in contact with the first surface except for the plurality of first portions. The second surface extends from the first end surface to the second end surface in the axial direction and is arranged along the fourth surface in a cross section of the rotor core perpendicular to the axial direction. A plurality of second grooves, and the fourth surface includes a plurality of second portions exposed in the plurality of second grooves, and the fourth surface includes the plurality of second grooves. In the cross section of the rotor core that is in contact with the second surface and perpendicular to the axial direction except for the second portion, the total length of the plurality of first portions is greater than the total length of the plurality of second portions. Is also big.

According to the present invention, there is an effect that the temperature increase of the permanent magnet due to the eddy current can be suppressed, the demagnetization resistance of the permanent magnet can be improved, and the efficiency of the electric motor can be improved.

1 is a cross-sectional view showing a configuration of a permanent magnet motor according to Embodiment 1. FIG. Cross-sectional view showing the configuration of the rotor core in the first embodiment Partial enlarged view of the rotor core shown in FIG. Cross-sectional view showing the configuration of the rotor in the first embodiment Partial enlarged view of the rotor shown in FIG. AA sectional view shown in FIG. The figure for demonstrating the relationship of the length in FIG. Partial enlarged cross-sectional view showing the configuration of the rotor according to the first modification of the first embodiment Partial enlarged cross-sectional view showing the configuration of the rotor according to the second modification of the first embodiment Vertical sectional view showing the configuration of the compressor according to the second embodiment The figure which shows the refrigerating cycle of the air conditioner which concerns on Embodiment 3. FIG. The figure which shows the structure of the air conditioner which concerns on Embodiment 3. FIG.

Hereinafter, embodiments of a permanent magnet electric motor, a compressor, and an air conditioner according to the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a cross-sectional view showing the configuration of the permanent magnet motor according to the present embodiment. 1 is a cross-sectional view perpendicular to the axial direction of the rotor core.

The electric motor 1 is a permanent magnet electric motor according to the present embodiment. The electric motor 1 includes an annular stator 2 and a rotor 3 disposed inside the stator 2. The rotor 3 is disposed inside the stator 2 so as to be rotatable through the gap 20.

The stator 2 includes an annular stator core 21 and a coil 22 wound around the stator core 21. The stator core 21 includes an annular yoke 23 and a plurality of teeth 24 protruding from the yoke 23. Each of the plurality of teeth 24 protrudes from the yoke 23 inward in the radial direction of the yoke 23. The stator core 21 is formed by punching electromagnetic steel sheets according to the planar shape of the stator core 21 and laminating a plurality of punched electromagnetic steel sheets in the axial direction of the stator core 21.

The plurality of teeth 24 are arranged at equal intervals in the circumferential direction of the yoke 23. Between adjacent teeth 24, a slot 25, which is a space, is formed. The coil 22 is wound around a plurality of teeth 24. In the illustrated example, the number of teeth 24 is nine, but is not limited thereto.

The rotor 3 includes an annular rotor core 4 and a plurality of permanent magnets 6 arranged inside the rotor core 4. The rotor core 4 is arranged coaxially with the stator core 21. That is, the axis of the rotor core 4 coincides with the axis of the stator core 21. In the following description, unless otherwise specified, the “axial direction” is the axial direction of the rotor core 4, the “radial direction” is the radial direction of the rotor core 4, and the “circumferential direction” is the rotor core. 4 circumferential directions.

The rotor core 4 is formed with a shaft hole 7 at the center. A shaft (not shown) is fitted into the shaft hole 7.

The rotor core 4 has a plurality of magnet holes 5 arranged in the circumferential direction. The plurality of magnet holes 5 are formed in the rotor core 4 at equal intervals in the circumferential direction. The plurality of magnet holes 5 are arranged at equidistant positions in the radial direction from the center of the rotor core 4. The plurality of magnet holes 5 have the same shape and the same size. The plurality of magnet holes 5 penetrates the rotor core 4 in the axial direction.

The magnet hole 5 extends in a direction orthogonal to the radial direction, and the length in the direction orthogonal to the radial direction is larger than the length in the radial direction. The rotor core 4 is formed by punching out electromagnetic steel sheets according to the planar shape of the rotor core 4 and laminating a plurality of punched electromagnetic steel sheets in the axial direction.

A plurality of permanent magnets 6 are disposed in the plurality of magnet holes 5. The permanent magnet 6 is fixed to the rotor core 4 by adhesion or press fitting.

The permanent magnet 6 has a flat plate shape and a rectangular cross section. The permanent magnet 6 extends in a direction orthogonal to the radial direction, and the length in the direction orthogonal to the radial direction is larger than the length in the radial direction. That is, the longitudinal direction of the permanent magnet 6 is a direction orthogonal to the radial direction, and the short direction of the permanent magnet 6 is the radial direction. The permanent magnet 6 is a rare earth magnet or a ferrite magnet. The permanent magnet 6 is a rare earth magnet containing iron, neodymium and boron, and the rare earth magnet does not contain dysprosium, or the dysprosium content contained in the rare earth magnet is 3% by weight or less. Can do.

The plurality of permanent magnets 6 have the same shape and the same size. The plurality of permanent magnets 6 are arranged so that the polarities of the magnetic poles on the outer peripheral side are alternated in the circumferential direction.

In the illustrated example, the number of poles of the electric motor 1 is 6, and the number of the magnet holes 5 and the number of the permanent magnets 6 are each 6. The number of magnet holes 5 and the number of permanent magnets 6 are determined according to the number of poles.

Next, the configuration of the rotor 3 will be described in detail with reference to FIGS. 2 is a cross-sectional view showing the structure of the rotor core, FIG. 3 is a partially enlarged view of the rotor core shown in FIG. 2, FIG. 4 is a cross-sectional view showing the structure of the rotor, and FIG. 5 is the rotation shown in FIG. FIG. 6 is an AA cross-sectional view shown in FIG. FIG. 6 is a part of a longitudinal sectional view of the rotor core 4 including the axis of the rotor core 4.

The rotor core 4 has a cylindrical outer peripheral surface 18a and a cylindrical inner peripheral surface 18b arranged coaxially with the outer peripheral surface 18a. The inner peripheral surface 18 b forms the shaft hole 7. The rotor core 4 has end faces 18c and 18d that are separated from each other in the axial direction. The end face 18c is a first end face, and the end face 18d is a second end face. In FIG. 6, the axis of the rotor core 4 is indicated by an axis 30. The end faces 18 c and 18 d are parallel to each other and perpendicular to the axis 30.

The rotor core 4 includes a core portion 4a disposed on the inner side in the radial direction from the plurality of magnet holes 5, and a plurality of core portions 4b disposed on the outer side in the radial direction from the plurality of magnet holes 5, respectively. .

The rotor core 4 has a plurality of inner surfaces 8 that form a plurality of magnet holes 5. The plurality of magnet holes 5 extend in the axial direction from the end surface 18c to the end surface 18d. The plurality of magnet holes 5 extend parallel to the shaft 30. The magnet hole 5 is a portion into which the permanent magnet 6 is substantially inserted, and has a rectangular shape according to the shape of the permanent magnet 6.

The inner surface 8 has a surface 8 a disposed on the outer side in the radial direction in the rotor core 4 and a surface 8 b disposed on the inner side in the radial direction in the rotor core 4. The surface 8a is a first surface, and the surface 8b is a second surface. That is, the surface 8a is disposed on the outer side in the radial direction with respect to the surface 8b, and the surface 8b is disposed on the inner side in the radial direction with respect to the surface 8a. The surface 8a is formed on the core portion 4b, and the surface 8b is formed on the core portion 4a.

The surface 8a has a plurality of grooves 9a. Specifically, the plurality of grooves 9a includes a groove 9a1, a groove 9a2, a groove 9a3, a groove 9a4, and a groove 9a5. The plurality of grooves 9a extend in the axial direction from the end surface 18c to the end surface 18d. That is, the plurality of grooves 9 a penetrate the rotor core 4. The plurality of grooves 9 a extend in parallel to the shaft 30. In addition, the plurality of grooves 9a are arranged apart from each other in the cross section of the rotor core 4 perpendicular to the axial direction.

The surface 8b has a plurality of grooves 9b. Specifically, the plurality of grooves 9b includes a groove 9b1, a groove 9b2, a groove 9b3, and a groove 9b4. The plurality of grooves 9b extend in the axial direction from the end surface 18c to the end surface 18d. That is, the plurality of grooves 9 b penetrate the rotor core 4. The plurality of grooves 9 b extend parallel to the shaft 30. In addition, the plurality of grooves 9b are spaced apart from each other in the cross section of the rotor core 4 perpendicular to the axial direction.

Thus, the plurality of grooves 9a communicate with the magnet hole 5 over the entire length of the rotor core 4 in the axial direction. Similarly, the plurality of grooves 9b communicate with the magnet hole 5 over the entire length of the rotor core 4 in the axial direction. The plurality of grooves 9a and the plurality of grooves 9b are cooling grooves.

The permanent magnet 6 has a surface 6 a facing the surface 8 a constituting the inner surface 8 and a surface 6 b facing the surface 8 b constituting the inner surface 8. The surface 6a is a third surface, and the surface 6b is a fourth surface. The

surfaces

6a and 6b are magnetic pole surfaces of the permanent magnet 6 having different polarities.

The plurality of grooves 9a are arranged along the surface 6a in the cross section of the rotor core 4 perpendicular to the axial direction. Further, the surface 6a has a plurality of portions 6a1 to 6a5 exposed in the plurality of grooves 9a. Specifically, the part 6a1 is exposed in the groove 9a1, the part 6a2 is exposed in the groove 9a2, the part 6a3 is exposed in the groove 9a3, the part 6a4 is exposed in the groove 9a4, and the part 6a5 is exposed in the groove 9a5. The plurality of portions 6a1 to 6a5 are a plurality of first portions. The surface 6a is in contact with the surface 8a except for the plurality of portions 6a1 to 6a5.

The plurality of grooves 9b are arranged along the surface 6b in the cross section of the rotor core 4 perpendicular to the axial direction. Further, the surface 6b has a plurality of portions 6b1 to 6b4 exposed in the plurality of grooves 9b. Specifically, the part 6b1 is exposed in the groove 9b1, the part 6b2 is exposed in the groove 9b2, the part 6b3 is exposed in the groove 9b3, and the part 6b4 is exposed in the groove 9a4. The plurality of portions 6b1 to 6b4 are a plurality of second portions. The surface 6b is in contact with the surface 8b except for the plurality of portions 6b1 to 6b4.

The permanent magnet 6 further has a surface 6c disposed at one end in the longitudinal direction and a surface 6d disposed at the other end in the longitudinal direction. The

surfaces

6 c and 6 d are parallel to each other and parallel to the axis 30.

The permanent magnet 6 further has a surface 6e disposed at one end in the axial direction and a surface 6f disposed at the other end in the axial direction. The

surfaces

6 e and 6 f are parallel to each other and are perpendicular to the axis 30. Further, the surface 6e is flush with the end surface 18c, and the surface 6f is flush with the end surface 18d. That is, the permanent magnet 6 extends in the axial direction from the end surface 18c to the end surface 18d.

Flux barrier portions

10a and 10b are provided on both sides of the permanent magnet 6 in the longitudinal direction. The

flux barrier portions

10a and 10b are

grooves

15a and 15b formed in portions of the inner surface 8 excluding the

surfaces

8a and 8b, respectively. The

grooves

15a and 15b extend in the axial direction from the end surface 18c to the end surface 18d. That is, the

grooves

15 a and 15 b penetrate the rotor core 4. The

grooves

15 a and 15 b extend parallel to the shaft 30. The

grooves

15a and 15b communicate with the magnet hole 5 over the entire length of the rotor core 4 in the axial direction.

The

flux barrier portions

10a and 10b bring the magnetic flux density distribution of the outer peripheral surface 18a of the rotor 3 closer to a sine wave, and the magnetic flux of the adjacent permanent magnet 6 is short-circuited via the rotor core 4, that is, suppresses leakage magnetic flux. .

A thin iron core 4c extending in the circumferential direction is formed between the flux barrier portion 10a and the outer peripheral surface 18a. Similarly, a thin iron core portion 4d extending in the circumferential direction is formed between the flux barrier portion 10b and the outer peripheral surface 18a. The thickness in the radial direction of the

thin core portions

4c and 4d is equal to or greater than the thickness of the electromagnetic steel plate of the rotor core 4. Thereby, when punching out the electromagnetic steel sheet, the

thin core portions

4c and 4d are suppressed from being twisted. Further, the thin

iron core portions

4c and 4d are suppressed from being cut when the rotor 3 rotates.

The rotor core 4 is formed with

protrusions

4e and 4f that regulate the circumferential displacement of the permanent magnet 6. Specifically, the

protrusions

4e and 4f are formed on the core 4a. A configuration in which the

protrusions

4e and 4f are not provided is also possible.

Next, details of the plurality of grooves 9a and the plurality of grooves 9b will be described with reference to FIG. 7 in addition to FIGS. FIG. 7 is a diagram for explaining the length relationship in FIG.

As shown in FIG. 7, in the cross section of the rotor core 4 perpendicular to the axial direction, the length of the part 6a1 is Wa1, the length of the part 6a2 is Wa2, the length of the part 6a3 is Wa3, and the length of the part 6a4 is Wa4, the length of the portion 6a5 is Wa5, the length of the portion 6b1 is Wb1, the length of the portion 6b2 is Wb2, the length of the portion 6b3 is Wb3, and the length of the portion 6b4 is Wb4. The length of the permanent magnet 6 in the longitudinal direction is Wm.

In the present embodiment, in the cross section of the rotor core 4 perpendicular to the axial direction, the total length of the plurality of portions 6a1 to 6a5 is larger than the total length of the plurality of portions 6b1 to 6b4. That is, the relationship of Wa1 + Wa2 + Wa3 + Wa4 + Wa5> Wb1 + Wb2 + Wb3 + Wb4 is established.

In the present embodiment, the total area of the plurality of grooves 9a is larger than the total area of the plurality of grooves 9b in the cross section of the rotor core 4 perpendicular to the axial direction. That is, in the cross section of the rotor core 4 perpendicular to the axial direction, the sum of the area of the groove 9a1, the area of the groove 9a2, the area of the groove 9a3, the area of the groove 9a4, and the area of the groove 9a5 is It is larger than the sum of the area of 9b2, the area of the groove 9b3, and the area of the groove 9b4.

In the present embodiment, in the cross section of the rotor core 4 perpendicular to the axial direction, the total length of the plurality of portions 6a1 to 6a5 is larger than the total length of the portion where the surface 6a and the surface 8a are in contact. In particular,
Wm / 2 <Wa1 + Wa2 + Wa3 + Wa4 + Wa5
The relationship holds.

Similarly, in the cross section of the rotor core 4 perpendicular to the axial direction, the total length of the plurality of portions 6b1 to 6b4 is larger than the total length of the portion where the surface 6b and the surface 8b contact. In particular,
Wm / 2 <Wb1 + Wb2 + Wb3 + Wb4
The relationship holds.

In the illustrated example, the following relationship holds.
Wa1 = Wa5
Wa2 = Wa3 = Wa4
Wa1> Wa2
In particular, any of the lengths of the two portions 6a1 and 6a5 located at both ends of the plurality of portions 6a1 to 6a5 in the arrangement direction of the plurality of portions 6a1 to 6a5 is greater than any of the lengths of the other portions 6a2 to 6a4. Is also big.

Further, in the illustrated example, the following relationship holds.
Wb1 = Wb2 = Wa3 = Wa4

Further, in the present embodiment, in the cross section of the rotor core 4 perpendicular to the axial direction, each of the plurality of grooves 9a has a width in the direction along the surface 6a that is away from the surface 6a, that is, from the inner side in the radial direction. It forms so that it may become small as it goes to the outer side in radial direction. That is, the width of each of the plurality of grooves 9a is the largest on the surface 6a and is equal to the length of the corresponding one of the plurality of portions 6a1 to 6a5.

Similarly, in the cross section of the rotor core 4 perpendicular to the axial direction, each of the plurality of grooves 9b has a width in the direction along the surface 6b that increases from the surface 6b, that is, from the outer side in the radial direction to the inner side in the radial direction. It is formed to become smaller as it goes. That is, the width of each of the plurality of grooves 9b is the largest on the surface 6b and is equal to the length of the corresponding one of the plurality of portions 6b1 to 6b4.

In the present embodiment, the plurality of grooves 9a and the plurality of grooves 9b are arranged in a staggered manner in the cross section of the rotor core 4 perpendicular to the axial direction. Specifically, the plurality of grooves 9a and the plurality of grooves 9b are arranged in a staggered manner along the surface 6a or the surface 6b. Alternatively, the plurality of grooves 9 a and the plurality of grooves 9 b are arranged in a staggered manner along the longitudinal direction of the permanent magnet 6.

In the illustrated example, the groove 9a2, the groove 9a3, and the groove 9a4 have the same shape and the same size. Specifically, each of the groove 9a2, the groove 9a3, and the groove 9a4 has an arc shape whose center angle is less than 180 °. The groove 9a1 and the groove 9a5 have the same shape and the same size when one of the groove 9a1 and the groove 9a5 is inverted.

In the illustrated example, the groove 9b1, the groove 9b2, the groove 9b3, and the groove 9a4 have the same shape and the same size. Specifically, each of the groove 9b1, the groove 9b2, the groove 9b3, and the groove 9a4 has an arc shape whose center angle is less than 180 °.

The effect of this embodiment will be described. In this Embodiment, while providing the some groove | channel 9a in the surface 8a arrange | positioned on the outer side in radial direction among the inner surfaces 8 which form the magnet hole 5, inside the radial direction among the inner surfaces 8 which form the magnet hole 5, A plurality of grooves 9b are provided on the surface 8b to be arranged.

With such a configuration, by allowing a gas or liquid having a temperature lower than that of the permanent magnet 6 to pass through the plurality of grooves 9a and the plurality of grooves 9b, the

surfaces

6a and 6b of the permanent magnet 6 can be directly cooled, The temperature rise of the permanent magnet 6 due to the eddy current can be suppressed, the demagnetization resistance of the permanent magnet 6 can be improved, and the efficiency of the electric motor 1 can be improved. Examples of gas include air or refrigerant gas, and examples of liquid include liquid refrigerant or oil.

In the present embodiment, in the cross section of the rotor core 4 perpendicular to the axial direction, the total length of the plurality of portions 6a1 to 6a5 is larger than the total length of the plurality of portions 6b1 to 6b4.

The temperature rise of the permanent magnet 6 due to the eddy current is not uniform within the permanent magnet 6, and the outer side in the radial direction is higher than the inner side. As in the present embodiment, by making the total length of the plurality of portions 6a1 to 6a5 larger than the total length of the plurality of portions 6b1 to 6b4, the outside of the permanent magnet 6 having a higher temperature rise can be further cooled.

Moreover, since the total length of the plurality of portions 6b1 to 6b4 exposed in the plurality of grooves 9b is relatively small inside the permanent magnet 6 where the temperature rise is relatively low, the magnetic flux of the permanent magnet 6 is effectively used. As a result, the efficiency of the electric motor 1 is improved.

In the present embodiment, the plurality of grooves 9a and the plurality of grooves 9b are arranged in a staggered manner in the cross section of the rotor core 4 perpendicular to the axial direction. As a result, the magnetic flux of the permanent magnet 6 can be used more effectively than in the case where the plurality of grooves 9a are arranged to face each other in the radial direction with the plurality of grooves 9b via the permanent magnet 6. Increases efficiency.

In the present embodiment, in the cross section of the rotor core 4 perpendicular to the axial direction, the total length of the plurality of portions 6a1 to 6a5 is larger than the total length of the plurality of portions 6b1 to 6b4, and the plurality of grooves 9a and The plurality of grooves 9b are arranged in a staggered manner in the cross section of the rotor core 4 perpendicular to the axial direction. However, any one of the configurations may be realized.

In the present embodiment, the total area of the plurality of grooves 9a is larger than the total area of the plurality of grooves 9b in the cross section of the rotor core 4 perpendicular to the axial direction. Thereby, the outer side of the permanent magnet 6 with a higher temperature rise can be cooled more effectively.

In the cross section of the rotor core 4 perpendicular to the axial direction, the total length of the plurality of portions 6a1 to 6a5 is larger than the total length of the plurality of portions 6b1 to 6b4, and the total area of the plurality of grooves 9a is the plurality of grooves 9b. A configuration with a total area of less than or equal to is also possible.

In the present embodiment, in the cross section of the rotor core 4 perpendicular to the axial direction, the total length of the plurality of portions 6a1 to 6a5 is larger than the total length of the portion where the surface 6a and the surface 8a are in contact. Thereby, the cooling of the surface 6a of the permanent magnet 6 can be further enhanced. In addition, in the cross section of the rotor core 4 perpendicular to the axial direction, a configuration in which the total length of the plurality of portions 6a1 to 6a5 is equal to or less than the total length of the portion where the surface 6a and the surface 8a are in contact is possible.

Similarly, in the cross section of the rotor core 4 perpendicular to the axial direction, the total length of the plurality of portions 6b1 to 6b4 is larger than the total length of the portion where the surface 6b and the surface 8b are in contact with each other. The cooling of 6b can be further increased. In addition, in the cross section of the rotor core 4 perpendicular to the axial direction, a configuration in which the total length of the plurality of portions 6b1 to 6b4 is equal to or less than the total length of the portion where the surface 6b and the surface 8b contact is possible.

In the present embodiment, the lengths of the two portions 6a1 and 6a5 located at both ends in the arrangement direction of the plurality of portions 6a1 to 6a5 among the plurality of portions 6a1 to 6a5 are the other portions 6a2 to 6a4. Greater than any of the lengths. The temperature rise of the permanent magnet 6 due to the eddy current is not uniform within the permanent magnet 6 and is higher at both ends in the longitudinal direction of the permanent magnet 6 than at the center. Therefore, the cooling of the permanent magnet 6 can be further enhanced by making the lengths of the two portions 6a1 and 6a5 located at both ends in the arrangement direction larger than the lengths of the other portions 6a2 to 6a4. In general, such a configuration is possible if the number of first portions is three or more.

In addition, the structure by which the length of the two parts 6a1 and 6a5 located at both ends in the arrangement direction is equal to or shorter than the lengths of the other parts 6a2 to 6a4 is also possible.

In addition, although the lengths of the plurality of portions 6b1 to 6b4 are equal to each other, the lengths of the two portions 6b1 and 6b4 positioned at both ends in the arrangement direction of the plurality of portions 6b1 to 6b4 among the plurality of portions 6b1 to 6b4 It is possible to adopt a configuration in which both are longer than any of the other portions 6b2 and 6b3. In general, such a configuration is possible if the number of second portions is three or more.

Further, the lengths of the plurality of portions 6a1 to 6a5 can be configured to increase from the center in the longitudinal direction of the permanent magnet 6 toward each end. Specifically, it can be configured such that a relationship of Wa1> Wa2> Wa3 and Wa5> Wa4> Wa3 is established. Even in this case, it is possible to obtain the same effect as when the lengths of the two portions 6a1 and 6a5 located at both ends in the arrangement direction are longer than the lengths of the other portions 6a2 to 6a4. The same applies to the lengths of the plurality of portions 6b1 to 6b4.

Further, in the present embodiment, in the cross section of the rotor core 4 perpendicular to the axial direction, each of the plurality of grooves 9a is formed such that the width in the direction along the surface 6a decreases as the distance from the surface 6a increases. Yes. Thereby, the magnetic flux of the permanent magnet 6 can easily pass through the rotor core 4, leading to effective use of the magnetic flux of the permanent magnet 6, and the efficiency of the electric motor 1 can be improved.

In addition, since the width in the direction along each surface 6a of the plurality of grooves 9a becomes larger as it is closer to the surface 6a, the surface 6a of the permanent magnet 6 can be efficiently cooled. In addition, the structure where the width | variety in the direction in alignment with each surface 6a of the some groove | channel 9a is not so large that it is close to the surface 6a is also possible.

Similarly, in the cross section of the rotor core 4 perpendicular to the axial direction, each of the plurality of grooves 9b is formed such that the width in the direction along the surface 6b decreases as the distance from the surface 6b increases. The efficiency of the electric motor 1 can be improved by effectively using the magnetic flux, and the surface 6b of the permanent magnet 6 can be efficiently cooled. In addition, the structure where the width | variety in the direction in alignment with each surface 6b of the some groove | channel 9b is not so large that it is close to the surface 6b is also possible.

In addition, at least one of the plurality of grooves 9a may have an arc shape with a central angle of 180 ° or less. Thereby, the process at the time of punching an electromagnetic steel plate and forming the some groove | channel 9a becomes easy. Similarly, at least one of the plurality of grooves 9b may have an arc shape with a central angle of 180 ° or less. In addition, the shape of the groove 9a or the groove 9b can be a rectangle or a triangle in addition to the arc shape.

Further, by improving the demagnetization resistance of the permanent magnet 6, it is possible to use a rare earth magnet having a small coercive force, and the cost can be reduced. The rare earth magnet having a small coercive force means that the content of dysprosium added to increase the coercive force is 3% by weight or less.

That is, in the present embodiment, the permanent magnet 6 is a rare earth magnet containing iron, neodymium, and boron, and does not contain dysprosium, or a rare earth magnet containing 3% by weight or less of dysprosium. it can.

In the present embodiment,

flux barrier portions

10a and 10b are air gaps, and can be used as cooling grooves in the same manner as the plurality of grooves 9a and the plurality of grooves 9b. A configuration in which the

flux barrier portions

10a and 10b are not provided, that is, a configuration in which the

grooves

15a and 15b are not provided is also possible.

Further, the

flux barrier portions

10a and 10b may not be voids, and the

grooves

15a and 15b may be filled with a nonmagnetic material such as resin.

The shape of the permanent magnet 6 is not limited to the illustrated example. In the illustrated example, the plurality of permanent magnets 6 are respectively arranged at positions corresponding to sides of a virtual regular polygon having the same number of corners as the number of permanent magnets 6 and arranged at equal intervals in the circumferential direction. However, the arrangement of the plurality of permanent magnets 6 is not limited to this.

In this embodiment, the number of the grooves 9a is five and the number of the grooves 9b is four. However, the present invention is not limited to this.

FIG. 8 is a partial enlarged cross-sectional view showing the configuration of the rotor according to the first modification of the present embodiment. In FIG. 8, the same components as those shown in FIGS. 2 to 7 are denoted by the same reference numerals.

In FIG. 8, in addition to the configuration shown in FIG. 7, grooves 9b5 and 9b6 are formed in the surface 8b. The grooves 9b5 and 9b6 are opposed to the grooves 9a1 and 9a5 in the radial direction through the permanent magnet 6, respectively. The length of the portion 6b5 exposed in the groove 9b5 is Wb5, and the length of the portion 6b6 exposed in the groove 9b6 is Wb6. The parts 6b5 and 6b6 are included in the surface 6b shown in FIG.

In FIG. 8, a relationship of Wa1 + Wa2 + Wa3 + Wa4 + Wa5> Wb1 + Wb2 + Wb3 + Wb4 + Wb5 + Wb6 is established. In addition to the relationship of Wm / 2 <Wa1 + Wa2 + Wa3 + Wa4 + Wa5, the relationship of Wm / 2 <Wb1 + Wb2 + Wb3 + Wb4 + Wb5 + Wb6 is established.

Since the grooves 9b5 and 9b6 are arranged facing both ends in the longitudinal direction of the permanent magnet 6 in the cross section of the rotor core 4 perpendicular to the axial direction, the grooves 9b5 and 9b6 in the longitudinal direction of the permanent magnet 6 having a higher temperature rise. Both end portions can be efficiently cooled. The effects according to the other configurations of the present modification are as described above.

FIG. 9 is a partially enlarged cross-sectional view showing the configuration of the rotor according to the second modification of the present embodiment. In FIG. 9, the same components as those shown in FIGS. 2 to 7 are denoted by the same reference numerals.

The difference between the configuration shown in FIG. 9 and the configuration shown in FIG. 7 is that, in FIG. 9, a plurality of grooves 9b11 to 9b15 are formed on the surface 8b. The length of the portion 6b11 exposed in the groove 9b11 is Wb11, the length of the portion 6b12 exposed in the groove 9b12 is Wb12, the length of the portion 6b13 exposed in the groove 9b13 is Wb13, and the length of the portion 6b14 exposed in the groove 9b14. The length of the portion 6b15 exposed in the groove 9b15 is Wb15. The parts 6b11 to 6b15 are included in the face 6b shown in FIG.

In FIG. 9, the relationship of Wa1 + Wa2 + Wa3 + Wa4 + Wa5> Wb11 + Wb12 + Wb13 + Wb14 + Wb15 is established. In addition to the relationship of Wm / 2 <Wa1 + Wa2 + Wa3 + Wa4 + Wa5, the relationship of Wm / 2 <Wb11 + Wb12 + Wb13 + Wb14 + Wb15 is established. FIG. 9 shows an example in which the plurality of grooves 9a and the plurality of grooves 9b are not arranged in a staggered manner. That is, the grooves 9b11 to 9b15 are opposed to the grooves 9a1 to 9a5 via the permanent magnet 6 in the radial direction, respectively. The effects according to the configuration of the present modification are as described above.

Embodiment 2. FIG.
FIG. 10 is a longitudinal sectional view showing the configuration of the compressor according to the present embodiment. In FIG. 10, the same components as those shown in FIGS. 1 to 7 are denoted by the same reference numerals.

The compressor 50 includes a compression unit 52 disposed in the sealed container 51, the electric motor 1 disposed above the compression unit 52 in the sealed container 51, and an accumulator 53 disposed outside the sealed container 51. A mechanism such as scroll, rotary, or reciprocation is applied to the compression unit 52.

The sealed container 51 is formed by processing a steel plate into a cylindrical shape by drawing. The sealed container 51 is provided with a suction pipe 54 and a discharge pipe 55. Refrigerating machine oil for lubrication is stored at the bottom of the sealed container 51.

The electric motor 1 is the electric motor according to the first embodiment. The stator core 21 is fixed to the inner peripheral surface of the sealed container 51 by welding, shrink fitting, cold fitting, or press fitting. Electric power is supplied to the coil 22 from a terminal 65 fixed to the sealed container 51. A shaft 56 is fixed to the rotor core 4. The shaft 56 has an eccentric portion 57 at the tip.

The compression part 52 includes a cylindrical cylinder 59 including a compression chamber 58, an annular piston 60 slidably fitted to an eccentric part 57 disposed in the cylinder 59, and a shaft above the eccentric part 57. 56, an upper frame 61 bearing the shaft 56, a lower frame 62 bearing the shaft 56 below the eccentric portion 57, an upper discharge muffler 63 attached to the upper frame 61, and a lower discharge muffler attached to the lower frame 62. 64.

The cylinder 59 is fixed to the inner peripheral surface of the sealed container 51 by welding, shrink fitting, cold fitting, or press fitting. A vane for separating the suction side and the compression side is provided in the cylinder 59, but the illustration is omitted.

The operation of the compressor 50 will be described. The accumulator 53 supplies refrigerant gas to the compression unit 52 via a suction pipe 54 provided in the sealed container 51. The refrigerant gas supplied from the accumulator 53 is introduced into the cylinder 59.

On the other hand, when the electric motor 1 is energized, the rotor 3 rotates, and the piston 60 rotates eccentrically along the inner peripheral surface of the cylinder 59 in conjunction with the shaft 56. Thereby, the refrigerant gas introduced into the cylinder 59 is compressed in the compression chamber 58.

The compressed refrigerant gas sequentially passes through a hole (not shown) and the upper discharge muffler 63 in the upper frame 61 or sequentially passes through a hole (not shown) and the lower discharge muffler 64 in the lower frame 62 to enter the space in the sealed container 51. After being discharged, it passes through the plurality of grooves 9 a, the plurality of grooves 9 b, or the gap 20, rises in the sealed container 51, and is supplied to the high-pressure side of the refrigeration cycle via the discharge pipe 55 provided in the sealed container 51. Is done. In addition, in FIG. 10, the main flow paths of the refrigerant gas are indicated by arrows.

In such a compressor 50, the refrigerant gas passing through the plurality of grooves 9a and the plurality of grooves 9b passes while contacting the surface of the permanent magnet 6. At this time, the refrigerant gas takes the heat of the permanent magnet 6 generated by the eddy current, and the temperature of the permanent magnet 6 is lowered. Since the permanent magnet 6 has a characteristic that it is more likely to be demagnetized as the temperature becomes higher, by reducing the temperature of the permanent magnet 6, the demagnetization resistance of the permanent magnet 6 is improved, and the compressor 50 is highly reliable and highly efficient. Can be provided.

Embodiment 3 FIG.
FIG. 11 is a diagram showing a refrigeration cycle of the air conditioner according to the present embodiment. The refrigeration cycle 70 includes a compressor 50, a four-way valve 71 that switches the flow of refrigerant discharged from the compressor 50, an outdoor heat exchanger 72 that performs heat exchange outdoors, an expansion valve 73 that reduces the pressure of the refrigerant, An indoor heat exchanger 74 that performs heat exchange indoors, a compressor 50, a four-way valve 71, an outdoor heat exchanger 72, an expansion valve 73, a refrigerant pipe 75 that connects the indoor heat exchanger 74 to each other, a compressor 50, And an expansion valve 73 and a control unit 36 for controlling the four-way valve 71. The compressor 50 is the compressor of the second embodiment.

FIG. 12 is a diagram showing a configuration of the air conditioner according to the present embodiment. The air conditioner 200 includes an indoor unit 210 and an outdoor unit 220 connected to the indoor unit 210. The outdoor unit 220 includes a compressor 50.

According to the present embodiment, since the air conditioner 200 includes the compressor 50, the air conditioner 200 having excellent demagnetization resistance, high reliability, and high efficiency can be obtained.

In addition, the electric motor 1 of Embodiment 1 can also be used for the fan 221 of the outdoor unit 220. Moreover, the electric motor 1 of Embodiment 1 can also be used for electrical equipment other than the air conditioner 200. Even in this case, the same effect as in the present embodiment can be obtained.

The configuration described in the above embodiment shows an example of the contents of the present invention, and can be combined with another known technique, and can be combined with other configurations without departing from the gist of the present invention. It is also possible to omit or change the part.

1 Electric motor, 2 stator, 3 rotor, 4 rotor core, 4a, 4b core, 4c, 4d thin core, 4e, 4f protrusion, 5 magnet hole, 6 permanent magnet, 6a, 6b, 6c, 6d , 6e, 6f, 8a, 8b, 6a1, 6a2, 6a3, 6a4, 6a5, 6b1, 6b2, 6b3, 6b4, 6b5, 6b6, 6b11, 6b12, 6b13, 6b14, 6b15, 7 shaft hole, 8 inner surface, 9a, 9a1, 9a2, 9a3, 9a4, 9a5, 9b, 9b1, 9b2, 9b3, 9b4, 9b5, 9b6, 9b11, 9b12, 9b13, 9b14, 9b15, 15a, 15b groove, 10a, 10b flux barrier part, 18a outer periphery Surface, 18b inner peripheral surface, 18c, 18d end face, 20 air gap, 21 stator core, 22 coils, 2 York, 24 teeth, 25 slots, 30 shafts, 36 control unit, 50 compressor, 51 airtight container, 52 compression unit, 53 accumulator, 54 suction pipe, 55 discharge pipe, 56 shaft, 57 eccentric part, 58 compression chamber, 59 Cylinder, 60 piston, 61 upper frame, 62 lower frame, 63 upper discharge muffler, 64 lower discharge muffler, 65 terminals, 70 refrigeration cycle, 71 four-way valve, 72 outdoor heat exchanger, 73 expansion valve, 74 indoor heat exchanger, 75 refrigerant piping, 200 air conditioner, 210 indoor unit, 220 outdoor unit, 221 fan.

Claims

An annular stator core;
The stator core is disposed coaxially with the stator core, has a plurality of magnet holes, and has a first end surface, a second end surface, and a plurality of inner surfaces, the first end surface and the The second end surfaces are spaced apart from each other in the axial direction, the plurality of inner surfaces form the plurality of magnet holes, the plurality of magnet holes arranged in a circumferential direction, and from the first end surface to the second end surface An annular rotor core extending in the axial direction;
A plurality of permanent magnets disposed in the plurality of magnet holes;
With
Each of the plurality of inner surfaces includes a first surface disposed on the outer side in the radial direction of the rotor core in the rotor core, and a second surface disposed on the inner side in the radial direction in the rotor core. Have
Each of the plurality of permanent magnets has a third surface facing the first surface and a fourth surface facing the second surface;
The plurality of first surfaces are arranged along the third surface in a cross section of the rotor core extending in the axial direction from the first end surface to the second end surface and perpendicular to the axial direction. A first groove of
The third surface has a plurality of first portions exposed in the plurality of first grooves,
The third surface is in contact with the first surface except for the plurality of first portions,
The second surface extends in the axial direction from the first end surface to the second end surface and is arranged along the fourth surface in a cross section of the rotor core perpendicular to the axial direction. A second groove of
The fourth surface has a plurality of second portions exposed in the plurality of second grooves,
The fourth surface is in contact with the second surface except for the plurality of second portions,
In the cross section of the rotor core perpendicular to the axial direction, a total length of the plurality of first portions is larger than a total length of the plurality of second portions.
The permanent magnet motor according to claim 1, wherein a total area of the plurality of first portions is larger than a total area of the plurality of second portions in a cross section of the rotor core perpendicular to the axial direction.
In the cross section of the rotor core perpendicular to the axial direction, the overall length of the plurality of first portions is larger than the overall length of the portion where the third surface and the first surface are in contact with each other. The permanent magnet motor described.
In the cross section of the rotor core perpendicular to the axial direction, the overall length of the plurality of second portions is larger than the overall length of the portion where the fourth surface and the second surface are in contact with each other. The permanent magnet motor described.
The number of the plurality of first portions is 3 or more,
In the cross section of the rotor core perpendicular to the axial direction, both of the lengths of two first portions located at both ends in the arrangement direction of the plurality of first portions among the plurality of first portions. The permanent magnet motor according to claim 1, wherein is longer than any of the lengths of the other first portions.
The number of the plurality of second portions is 3 or more,
In the cross section of the rotor core perpendicular to the axial direction, any of the lengths of two second portions located at both ends in the arrangement direction of the plurality of second portions among the plurality of second portions The permanent magnet motor according to claim 1, wherein is longer than any of the lengths of the other second portions.
In the cross section of the rotor core perpendicular to the axial direction, each of the plurality of first grooves has a width in a direction along the third surface that extends from an inner side in the radial direction to an outer side in the radial direction. The permanent magnet motor according to claim 1, wherein the permanent magnet motor is formed to be small.
In the cross section of the rotor core perpendicular to the axial direction, each of the plurality of second grooves has a width in a direction along the fourth surface that increases from an outer side in the radial direction toward an inner side in the radial direction. The permanent magnet motor according to claim 1, wherein the permanent magnet motor is formed to be small.
The permanent magnet electric motor according to claim 1, wherein at least one of the plurality of first grooves has an arc shape having a central angle of 180 ° or less.
2. The permanent magnet motor according to claim 1, wherein at least one of the plurality of second grooves has an arc shape having a central angle of 180 ° or less.
The permanent magnet motor according to claim 1, wherein the plurality of first grooves and the plurality of second grooves are arranged in a staggered manner in a cross section of the rotor core perpendicular to the axial direction.
Each of the plurality of permanent magnets is a rare earth magnet containing iron, neodymium and boron, and the rare earth magnet does not contain dysprosium, or the content of dysprosium contained in the rare earth magnet is 3% by weight. The permanent magnet motor according to claim 1, wherein:
An annular stator core;
The stator core is disposed coaxially with the stator core, has a plurality of magnet holes, and has a first end surface, a second end surface, and a plurality of inner surfaces, the first end surface and the The second end surfaces are spaced apart from each other in the axial direction, the plurality of inner surfaces form the plurality of magnet holes, the plurality of magnet holes arranged in a circumferential direction, and from the first end surface to the second end surface An annular rotor core extending in the axial direction;
A plurality of permanent magnets disposed in the plurality of magnet holes;
With
Each of the plurality of inner surfaces includes a first surface disposed on the outer side in the radial direction of the rotor core in the rotor core, and a second surface disposed on the inner side in the radial direction in the rotor core. Have
Each of the plurality of permanent magnets has a third surface facing the first surface and a fourth surface facing the second surface;
The plurality of first surfaces are arranged along the third surface in a cross section of the rotor core extending in the axial direction from the first end surface to the second end surface and perpendicular to the axial direction. A first groove of
The third surface has a plurality of first portions exposed in the plurality of first grooves,
The third surface is in contact with the first surface except for the plurality of first portions,
The second surface extends in the axial direction from the first end surface to the second end surface and is arranged along the fourth surface in a cross section of the rotor core perpendicular to the axial direction. A second groove of
The fourth surface has a plurality of second portions exposed in the plurality of second grooves,
The fourth surface is in contact with the second surface except for the plurality of second portions,
In the cross section of the rotor core perpendicular to the axial direction, the plurality of first grooves and the plurality of second grooves are arranged in a staggered manner.
A compressor provided with the permanent magnet motor according to any one of claims 1 to 13.
An air conditioner comprising the compressor according to claim 14.