WO2023085216A1

WO2023085216A1 - Rotor, motor, compressor, and air-conditioning device

Info

Publication number: WO2023085216A1
Application number: PCT/JP2022/041291
Authority: WO
Inventors: 義博片岡; 達也小川; 清隆西嶋
Original assignee: ダイキン工業株式会社
Priority date: 2021-11-12
Filing date: 2022-11-07
Publication date: 2023-05-19
Also published as: JP2023072558A; JP7381914B2

Abstract

The present invention provides a rotor that is for a motor, that enables reduction in use amount of magnets, and that enables relaxation of stress occurring at shrink-fitting of a shaft. A rotor (10) is provided so as to be rotatable about the rotation axis (C), and comprises a first magnet (41), a second magnet (42), and a third magnet (43). When viewed along the rotation axis (C), the first magnet (41) and the second magnet (42) extend from the inner side to the outer side of the rotor (10), and have a tabular shape. The third magnet (43) is disposed between the inner side end of the first magnet (41) and the inner side end of the second magnet (42), and has a shape projecting toward the inner side when viewed along the rotation axis (C). When viewed along the rotation axis (C), the thickness of the third magnet (43) at the central portion in the circumferential direction of the rotor (10) is smaller than the thickness of the first magnet (41) and the second magnet (42).

Description

Rotors, motors, compressors and air conditioners

　Regarding rotors, motors, compressors, and air conditioners.

Patent Document 1 (Japanese Patent Application Laid-Open No. 2016-171646) describes a motor rotor in which a plurality of permanent magnets are embedded. When viewed along the axis of rotation of the rotor, each permanent magnet consists of two flat magnets extending outward from the inside of the rotor and one curved magnet connecting the inner ends of the two flat magnets. Consists of

In the rotor described in Patent Document 1 (Japanese Patent Application Laid-Open No. 2016-171646), the curved magnets are farther from the outer peripheral surface of the rotor than the flat plate magnets, so they are demagnetized by the magnetic field generated by the stator of the motor. hard to do. Therefore, the demagnetization resistance of the curved magnet may become excessive. In addition, since the distance from the shaft attached to the rotor to the holes in the rotor in which the curved magnets are accommodated is shortened, the stress on the inner diameter of the rotor core increases when the shaft is shrink-fitted to the rotor. Also, the thermal stress applied to the curved magnet during shrink fitting may increase.

The rotor of the first aspect is a rotor of a motor that is rotatable around a rotation axis. The rotor includes a first magnet, a second magnet and a third magnet. The first magnet and the second magnet extend from the inner side to the outer side of the rotor when viewed along the rotation axis, and have a flat plate shape. The third magnet is disposed between the inner end of the first magnet and the inner end of the second magnet, and has a shape convex inward when viewed along the rotation axis. have. When viewed along the rotation axis, the thickness of the central portion of the third magnet in the circumferential direction of the rotor is smaller than the thickness of the first and second magnets.

With this rotor, it is possible to reduce costs by reducing the amount of magnets used. In addition, in this rotor, the stress on the inner diameter of the rotor due to the shrink fitting of the shaft to the rotor can be reduced. By reducing the heat transferred to the third magnet, the thermal stress applied to the third magnet can be reduced.

The rotor of the second aspect is the rotor of the first aspect, and when viewed along the rotation axis, the thickness of both ends of the third magnet in the circumferential direction is equal to the thickness of the first magnet and the second magnet. is equal to

The rotor of the third aspect is the rotor of the first aspect or the second aspect, and when viewed along the rotation axis, the thickness of the third magnet is such that the thickness of the third magnet increases from both ends toward the center in the circumferential direction. gradually become smaller.

The rotor of the fourth aspect is the rotor of any one of the first to third aspects, and when viewed along the rotation axis, the inner edge and the outer edge of the third magnet are circular arcs. be. The center of the arc that is the inner edge of the third magnet is located outside the center of the arc that is the outer edge of the third magnet.

The rotor of the fifth aspect is the rotor of any one of the first to fourth aspects, and the first, second and third magnets are ferrite magnets.

With this rotor, it is possible to reduce costs by reducing the amount of magnets used.

A motor according to the sixth aspect includes a stator and a rotor according to any one of the first to fifth aspects.

With this motor, it is possible to reduce costs by reducing the amount of magnets embedded in the rotor.

The compressor of the seventh aspect includes the motor of the sixth aspect.

With this compressor, it is possible to reduce costs by reducing the amount of magnets embedded in the rotor of the motor.

The air conditioner of the eighth aspect includes the compressor of the seventh aspect.

With this air conditioner, it is possible to reduce costs by reducing the amount of magnets embedded in the rotor of the compressor motor.

It is a top view of rotor 10 of an embodiment. 3 is a plan view of rotor 10 with end plate 30 and fastener 50 removed. FIG. 3 is a plan view of an end plate 30 of the rotor 10; FIG. FIG. 2 is a cross-sectional view taken along line IV-IV of FIG. 1; 4 is a plan view of the permanent magnets 40 housed in the magnet housing holes 22 as viewed along the rotation axis C. FIG. 4 is an external view of a first magnet 41 and a second magnet 42; FIG. 4 is an external view of a third magnet 43; FIG. 2 is a cross-sectional view of motor 100. FIG. 2 is a longitudinal sectional view of compressor 200. FIG. FIG. 4 is a cross-sectional view of a permanent magnet 140 housed in a magnet housing hole 22 as a comparative example; FIG. 11 is a cross-sectional view of a permanent magnet 40 housed in a magnet housing hole 22 in a first modified example; FIG. 11 is a cross-sectional view of a permanent magnet 40 housed in a magnet housing hole 22 in a second modified example;

A rotor, a motor including the rotor, and a compressor including the motor according to an embodiment of the present disclosure will be described with reference to the drawings.

(1) Configuration of Rotor 10 As shown in FIGS. 1 to 4, the rotor 10 mainly has a rotor core 20, end plates 30, permanent magnets 40, and fasteners 50. FIG. In FIG. 1, the permanent magnet 40 is omitted. A shaft through-hole 11 for attaching a shaft 60 is formed in the rotor 10 .

(1-1) Rotor core 20
Rotor core 20 is formed by laminating a plurality of steel plates. Rotor core 20 has a cylindrical shape. The rotor core 20 has a rotation axis C passing through the centers of the two circular surfaces of its cylindrical shape. The rotor core 20 is mainly formed with one shaft housing hole 21 , a plurality of magnet housing holes 22 and a plurality of fastener housing holes 23 . A shaft receiving hole 21 , a magnet receiving hole 22 , and a fastener receiving hole 23 pass through the rotor core 20 along the rotation axis C. As shown in FIG.

The shaft housing hole 21 is a hole through which the shaft 60 passes and for holding the shaft 60 . When viewed along the rotation axis C, the shaft receiving hole 21 has a circular shape. The circular center of the shaft receiving hole 21 is on the rotation axis C. As shown in FIG.

The magnet housing hole 22 is a hole for housing the permanent magnet 40 and holding the permanent magnet 40 . When viewed along the rotation axis C, the magnet housing hole 22 has a substantially U shape. When viewed along the rotation axis C, the magnet housing holes 22 have a shape that protrudes toward the inside of the rotor 10 . In this embodiment, the rotor core 20 has six magnet receiving holes 22 . As shown in FIGS. 1 and 2, the six magnet housing holes 22 are arranged at six-fold symmetrical positions about the rotation axis C. As shown in FIG. In other words, when viewed along the rotation axis C, two adjacent magnet housing holes 22 are separated from each other by 60° along the circumferential direction of the rotor 10 . The magnet housing hole 22 has a shape symmetrical with respect to line IV-IV shown in FIG.

The fastener housing hole 23 is a hole for housing the fastener 50 and holding the fastener 50 . When viewed along the rotation axis C, the fastener receiving hole 23 has a circular shape. In this embodiment, the rotor core 20 has six fastener receiving holes 23 . As shown in FIGS. 1 and 2, the six fastener receiving holes 23 are arranged at six-fold symmetry around the rotation axis C. As shown in FIG. In other words, when viewed along the rotation axis C, two adjacent fastener receiving holes 23 are separated by 60° along the circumferential direction of the rotor 10 . The fastener receiving holes 23 are positioned outside the rotor 10 relative to the magnet receiving holes 22 on line IV-IV shown in FIG.

(1-2) End plate 30
The end plate 30 is a member that prevents the permanent magnet 40 from coming off the magnet housing hole 22 . As shown in FIG. 4, one end plate 30 is attached to each of the upper surface 25 and the lower surface 26 of the rotor core 20 . The end plate 30 is made of a non-magnetic material such as stainless steel or aluminum.

As shown in FIG. 3, the end plate 30 has a disk shape. End plate 30 is formed with a shaft opening 31 and a plurality of fastener openings 33 .

The shaft opening 31 is a hole through which the shaft 60 passes. When viewed along the axis of rotation C, the shaft opening 31 has a circular shape. The circular center of the shaft opening 31 is on the rotation axis C. As shown in FIG. When the end plate 30 is attached to the rotor core 20 and viewed along the rotation axis C, the shaft opening 31 overlaps the shaft receiving hole 21 . The outer diameter of the shaft opening 31 is larger than the outer diameter of the shaft receiving hole 21 . The shaft through hole 11 is composed of a shaft receiving hole 21 and a shaft opening 31 .

The fastener opening 33 is a hole through which the fastener 50 passes. When viewed along axis of rotation C, fastener opening 33 has a circular shape. With the end plate 30 attached to the rotor core 20 , the fastener opening 33 overlaps the fastener receiving hole 23 when viewed along the rotation axis C. As shown in FIG. The outer diameter of the fastener opening 33 is smaller than the outer diameter of the fastener receiving hole 23 .

As shown in FIG. 4, both ends of the magnet housing hole 22 in the direction of the rotation axis C are closed by end plates 30, respectively. This prevents the permanent magnets 40 housed in the magnet housing holes 22 from coming off the magnet housing holes 22 .

(1-3) Permanent magnet 40
The permanent magnets 40 magnetize the rotor core 20 . The permanent magnet 40 is composed of a first magnet 41 , a second magnet 42 and a third magnet 43 . The first magnet 41, the second magnet 42 and the third magnet 43 are ferrite magnets. The first magnet 41, the second magnet 42 and the third magnet 43 may be bond magnets.

As shown in FIG. 5, each magnet accommodation hole 22 accommodates one first magnet 41, one second magnet 42, and one third magnet 43. As shown in FIG. An arrow M shown in FIG. 5 represents the magnetization direction of the permanent magnet 40 .

The first magnet 41 and the second magnet 42 have a substantially flat plate shape as shown in FIG. Corners of the first magnet 41 and the second magnet 42 are chamfered. When viewed along the rotation axis C, the first magnets 41 and the second magnets 42 are arranged to extend from the inside to the outside of the rotor 10 . FIG. 6 shows the dimension L1 in the direction along the rotation axis C, the dimension L2 in the direction from the inside to the outside of the rotor 10, and the dimension in the circumferential direction of the rotor 10 for the first magnet 41 and the second magnet 42. L3 is shown. As shown in FIG. 4, the dimension L1 is equal to or slightly shorter than the dimension of the magnet housing hole 22 in the direction of the rotation axis C. As shown in FIG. Dimension L2 is between 20% and 80% of the distance R between the outer and inner surfaces of rotor core 20 (FIG. 2). Dimension L3 is between 10% and 100% of dimension L2. Dimension L3 is constant in the direction from the inside to the outside of rotor 10 except for the chamfered corners of first magnet 41 and second magnet 42 .

The third magnet 43 has a curved shape when viewed along the rotation axis C, as shown in FIG. The corners of the third magnet 43 are chamfered. The third magnet 43 is arranged between the first end 41 a of the first magnet 41 inside the rotor 10 and the second end 42 a of the second magnet 42 inside the rotor 10 . The third magnet 43 has a third end 43 a that contacts the first end 41 a of the first magnet 41 and a fourth end 43 b that contacts the second end 42 a of the second magnet 42 . FIG. 7 shows the dimension L4 in the direction along the rotation axis C with respect to the third magnet 43. As shown in FIG. Dimension L4 is the same as dimension L1.

When viewed along the rotation axis C, the third magnet 43 has a shape that protrudes toward the inside of the rotor 10 . As shown in FIG. 5, when viewed along the rotation axis C, an inner edge 43c, which is the edge of the third magnet 43 inside the rotor 10, and an edge of the third magnet 43 outside the rotor 10 The outer edge 43d has an arc shape.

Hereinafter, the thickness T3 of the first magnet 41 and the second magnet 42 when viewed along the rotation axis C is the dimension L3, and the thickness of the third magnet 43 is the distance between the inner edge 43c and the outer edge 43d. Suppose that When viewed along the rotation axis C, the thickness T1 of the central portion 43e of the third magnet 43 in the circumferential direction of the rotor 10 is smaller than the thickness T3 of the first magnet 41 and the second magnet 42 . Further, when viewed along the rotation axis C, the thickness T2 of the third end portion 43a and the fourth end portion 43b, which are both ends of the third magnet 43 in the circumferential direction of the rotor 10, is equal to that of the first magnet 41 and It is equal to the thickness T3 of the second magnet 42 . When viewed along the rotation axis C, the thickness of the third magnet 43 gradually decreases from the third end portion 43a and the fourth end portion 43b toward the central portion 43e. The thickness T1 of the central portion 43e of the third magnet 43 is smaller than the thickness T2 of the third end portion 43a and the fourth end portion 43b of the third magnet 43 by 3% to 50%.

The shape of the third magnet 43 is not particularly limited as long as it satisfies the above conditions. For example, as shown in FIG. 5, when the third magnet 43 is viewed along the rotation axis C, the center P1 of the arc of the inner edge 43c is closer to the rotor 10 than the center P2 of the arc of the outer edge 43d. It may have a shape that is closer to the outside.

The rotor 10 of this embodiment is a six-pole rotor in which permanent magnets 40 are held in each of the six magnet housing holes 22 . The number of poles of rotor 10 is not limited to six. For example, the number of poles of the rotor 10 may be 4 poles, 8 poles or 10 poles. In this case, the rotor core 20 has the same number of magnet accommodation holes 22 as the number of poles of the rotor 10 .

(1-4) Fastener 50
The fasteners 50 fix the rotor core 20 and the two end plates 30 to each other. Fasteners 50 are, for example, rivets, bolts, and nuts. The fasteners 50 fasten the fastener openings 33 of the end plate 30 on the upper surface 25 side of the rotor core 20 , the fastener receiving holes 23 of the rotor core 20 , and the end plate 30 on the lower surface 26 side of the rotor core 20 . is positioned to pass through the tool opening 33 . After that, the rotor core 20 and the two end plates 30 are fixed to each other by a method such as crimping the lower ends of the fasteners 50 .

(2) Configuration of Motor 100 As shown in FIG. 8 , motor 100 mainly has rotor 10 and stator 70 . The rotor 10 is rotatably provided around the rotation axis C. As shown in FIG. A cylindrical shaft 60 is fixed to the shaft through-hole 11 of the rotor 10 by shrink fitting. The stator 70 is arranged outside the rotor 10 so as to surround the rotor 10 . A gap is formed between the rotor 10 and the stator 70 . The stator 70 mainly has a stator core 71 and coils 72 .

The stator core 71 is made of a ferromagnetic material such as an electromagnetic steel plate, for example. The stator core 71 has a back yoke 71a and a plurality of teeth 71b. The back yoke 71a has a substantially cylindrical shape. The teeth 71b protrude in the radial direction of the back yoke 71a from the inner peripheral surface of the back yoke 71a. In the stator core 71, nine teeth 71b are arranged at regular intervals in the circumferential direction of the back yoke 71a.

The coil 72 is formed, for example, by winding a wire around each tooth 71b. A space in which the winding of the coil 72 is accommodated is formed between two teeth 71b adjacent in the circumferential direction. An insulating member such as an insulating film is arranged between the teeth 71 b and the coil 72 . The stator core 71 has nine coils 72 . However, the number of coils 72 is not particularly limited.

When the motor 100 is driven, the coils 72 of the stator 70 are selectively energized sequentially according to a predetermined sequence, causing the rotor 10 to rotate about the rotation axis C together with the shaft 60 .

(3) Configuration of Compressor 200 Compressor 200 is used in a refrigeration system. A refrigeration system is, for example, an air conditioner capable of cooling and heating a room such as a building by performing a vapor compression refrigeration cycle. The air conditioner includes, for example, a refrigerant circuit in which the compressor 200 of the present embodiment, a four-way switching valve, an outdoor heat exchanger, an expansion mechanism, and an indoor heat exchanger are connected. In this case, the compressor 200, the four-way switching valve, the outdoor heat exchanger, and the expansion mechanism are mounted on the outdoor unit of the air conditioner, and the indoor heat exchanger is mounted on the indoor unit of the air conditioner. The four-way switching valve switches between a refrigerant circuit during cooling operation and a refrigerant circuit during heating operation. During cooling operation, the outdoor heat exchanger functions as a radiator (condenser), and the indoor heat exchanger functions as a heat absorber (evaporator). During heating operation, the outdoor heat exchanger functions as a heat absorber, and the indoor heat exchanger functions as a radiator. Compressor 200 compresses refrigerant circulating in a refrigerant circuit of a refrigeration system such as an air conditioner. Compressor 200 is, for example, a rotary compressor or a scroll compressor.

As shown in FIG. 9, the compressor 200 mainly includes a casing 210, a compression mechanism 215, a motor 100, a shaft 60, a suction pipe 219 and a discharge pipe 220. Casing 210 is a closed container that accommodates compression mechanism 215 , motor 100 and shaft 60 . Suction pipe 219 and discharge pipe 220 pass through casing 210 and are airtightly connected to casing 210 .

The compression mechanism 215 compresses low-pressure refrigerant supplied from an external refrigerant circuit through a suction pipe 219 . The refrigerant compressed by the compression mechanism 215 is discharged into the high-pressure space S1 inside the casing 210 and supplied to the external refrigerant circuit through the discharge pipe 220 . A compression chamber 215 a is formed inside the compression mechanism 215 . Compression mechanism 215 is coupled to shaft 60 . Compression mechanism 215 compresses the refrigerant by increasing or decreasing the volume of compression chamber 215 a using power supplied by rotating shaft 60 .

The motor 100 is arranged above or below the compression mechanism 215 . A stator 70 of motor 100 is fixed to the inner wall surface of casing 210 . Rotor 10 of motor 100 is rotatably arranged inside stator 70 .

The shaft 60 is arranged so that its axial direction is along the vertical direction. Shaft 60 is connected to rotor 10 of motor 100 and a member forming compression chamber 215 a of compression mechanism 215 . When the rotor 10 rotates around the rotation axis C by driving the motor 100 , the shaft 60 rotates and the refrigerant is compressed by the compression mechanism 215 .

(4) Characteristics In motors (IPM motors) in which permanent magnets are embedded inside a rotor, ferrite magnets or rare earth magnets, for example, are used as permanent magnets. However, ferrite magnets have a smaller magnetic force than rare earth magnets. Therefore, when ferrite magnets are used, an electromagnetic structure is adopted in which the surface area of the magnets is increased, as shown in FIG. 10, in order to improve the performance of the motor. FIG. 10 is a cross-sectional view similar to FIG. 5, showing the permanent magnets 140 that are housed in the magnet housing holes 22 of the rotor 10 and have a substantially U-shape. Permanent magnet 140 is composed of two flat magnets 141 and one curved magnet 142 . The flat magnets 141 extend from the outside of the rotor 10 toward the inside. Curved magnet 142 has a shape that protrudes toward the inside of rotor 10 . Both ends of the curved magnet 142 are in contact with the inner ends of the plate-like magnets 141 .

The vicinity of the outer surface of the rotor 10 is easily demagnetized by the magnetic field generated by the coil 72 because the distance from the stator 70 is short. To reduce the effects of demagnetization, the outer ends of the planar magnets 141 are located near the outer surface of the rotor 10, as shown in FIG. Conventionally, the thickness T12 of the curved magnet 142 is constant between both ends of the curved magnet 142 and equal to the thickness T11 of the planar magnet 141 . In other words, when viewed along the rotation axis C, the thickness of the permanent magnet 140 is constant in the longitudinal direction. Thicknesses T11 and T12 of the permanent magnet 140 are set large in order to reduce the influence of demagnetization due to the magnetic field generated from the coil 72 and improve the demagnetization resistance.

On the other hand, in the embodiment, when viewed along the rotation axis C, the thickness of the permanent magnet 40 is not constant in the longitudinal direction. Specifically, as shown in FIG. 5, the thickness T1 of the central portion 43e of the third magnet 43 is smaller than the thickness T2 of the third end portion 43a and the fourth end portion 43b of the third magnet 43, and It is smaller than the thickness T3 of the first magnet 41 and the second magnet 42 . Since the central portion 43 e of the third magnet 43 is the portion of the permanent magnet 40 that is farthest from the outer surface of the rotor 10 , the central portion 43 e of the third magnet 43 is attenuated by the magnetic field generated by the coil 72 . This is a location that is not easily affected by magnetism. Therefore, if the thickness T12 of the curved magnet 142 is the same as the thickness T11 of the planar magnet 141 as in the case of the permanent magnet 140, the demagnetization resistance tends to be excessive especially in the central portion 142a of the curved magnet 142.

In the embodiment, the thickness T1 of the central portion 43e of the third magnet 43 is smaller than the thickness T3 of the first magnet 41 and the second magnet 42. By reducing the thickness T1 of the central portion 43e of the third magnet 43, which is less likely to be affected by demagnetization due to the magnetic field generated by the coil 72, the volume of the permanent magnet 40 is reduced. As a result, the amount of permanent magnets 40 used can be reduced, so that the cost of the rotor 10 can be reduced.

Further, in order to reduce the thickness T1 of the central portion 43e of the third magnet 43, the center of the arc of the inner edge 43c is brought closer to the outside of the rotor 10, so that the inner surface of the rotor 10 and the third magnet 43 The distance to the central portion 43e can be increased. As a result, the stress on the inner diameter portion of the rotor 10 (rotor core 20) due to the shrink fitting of the shaft 60 to the rotor 10 can be reduced. Moreover, the heat transferred to the third magnets 43 when the inner diameter portion of the rotor 10 is heated and the shaft 60 is shrink-fitted can be reduced, and the thermal stress applied to the third magnets 43 can be reduced. The inner diameter portion of the rotor 10 is a portion inside the third magnet 43 when viewed along the rotation axis C. As shown in FIG.

(5) Modifications (5-1) First Modification A modification of the permanent magnet 40 will be described with reference to the drawings. In this modification, as shown in FIG. 11, when viewed along the rotation axis C, the thickness T1 of the center portion 43e of the third magnet 43 is equal to the thickness T1 of the third end portion 43a of the third magnet 43 and the fourth It is equal to the thickness T2 of the end portion 43b and smaller than the thickness T3 of the first magnet 41 and the second magnet . Therefore, when viewed along the rotation axis C, the thickness of the third magnet 43 is constant from the third end portion 43a and the fourth end portion 43b of the third magnet 43 toward the central portion 43e. In this case, for example, when viewed along the rotation axis C, the arc center of the outer edge 43 d of the third magnet 43 coincides with the arc center of the inner edge 43 c of the third magnet 43 . Further, as shown in FIG. 11, the thickness of the permanent magnet 40 is discontinuous at the contact portion between the first magnet 41 and the third magnet 43 and at the contact portion between the second magnet 42 and the third magnet 43. change to The thickness T1 of the third magnet 43 is 5% to 25% smaller than the thickness T3 of the first magnet 41 and the second magnet .

Further, in this modification, the thickness T1 of the central portion 43e of the third magnet 43 may be smaller than the thickness T2 of the third end portion 43a and the fourth end portion 43b of the third magnet 43. For example, when viewed along the rotation axis C, the thickness of the third magnet 43 may gradually decrease from the third end 43a and the fourth end 43b toward the central portion 43e.

Also in this modified example, the volume of the permanent magnets 40 can be reduced and the amount of permanent magnets 40 used can be reduced, so the cost of the rotor 10 can be reduced.

(5-2) Second Modification A modification of the permanent magnet 40 will be described with reference to the drawings. In this modification, as shown in FIG. 12, when viewed along the rotation axis C, the thickness T1 of the center portion 43e of the third magnet 43 is equal to the thickness T1 of the third end portion 43a of the third magnet 43 and the fourth It is smaller than the thickness T2 of the end portion 43b. The thickness T2 of the third end portion 43a and the fourth end portion 43b of the third magnet 43 is equal to the thickness T3 of the first magnet 41 and the second magnet . Therefore, when viewed along the rotation axis C, the thickness of the third magnet 43 decreases from the third end portion 43a and the fourth end portion 43b of the third magnet 43 toward the central portion 43e. In this modification, the thickness T1 of the central portion 43e of the third magnet 43 is 3% to 50% smaller than the thickness T2 of the third end portion 43a and the fourth end portion 43b of the third magnet 43. FIG.

In this modification, for example, as shown in FIG. 12, when viewed along the rotation axis C, the inner edge 43c of the third magnet 43 has an arc shape at the third end 43a and the fourth end 43b. and a second inner edge portion 43c2 having a linear shape at the central portion 43e. In this case, when viewed along the rotation axis C, the second inner edge portion 43 c 2 extends along a direction orthogonal to the radial direction of the rotor core 20 . The arc center of the first inner edge portion 43 c 1 may coincide with the arc center of the outer edge 43 d of the third magnet 43 . The third magnet 43 shown in FIG. 12 has a shape obtained by cutting the inside of the curved magnet 142 shown in FIG. ing.

In this modified example, if the thickness T1 of the central portion 43e of the third magnet 43 is smaller than the thickness T2 of the third end portion 43a and the fourth end portion 43b of the third magnet 43, the second inner edge portion 43c2 is rotated. When viewed along axis C, it may have a shape other than a rectilinear shape. For example, the second inner edge portion 43c2 may have an arc shape when viewed along the rotation axis C.

Also in this modified example, the volume of the permanent magnets 40 can be reduced and the amount of permanent magnets 40 used can be reduced, so the cost of the rotor 10 can be reduced. Moreover, the stress on the inner diameter portion of the rotor 10 due to the shrink fitting of the shaft 60 to the rotor 10 can be reduced. Moreover, the heat transferred to the third magnets 43 when the inner diameter portion of the rotor 10 is heated and the shaft 60 is shrink-fitted can be reduced, and the thermal stress applied to the third magnets 43 can be reduced.

(5-3) Third Modification In the embodiment, the permanent magnet 40 is composed of a first magnet 41, a second magnet 42 and a third magnet 43. FIG. However, the permanent magnet 40 may be composed of one magnet in which the first magnet 41, the second magnet 42 and the third magnet 43 are integrated.

- Conclusion -
Although embodiments of the present disclosure have been described above, it will be appreciated that various changes in form and detail may be made without departing from the spirit and scope of the present disclosure as set forth in the appended claims. .

10: rotor 41: first magnet 42: second magnet 43: third magnet 70: stator 100: motor 200: compressor C: rotating shaft

JP 2016-171646 A

Claims

A rotor of a motor provided rotatably around a rotation axis (C),
a first magnet (41) and a second magnet (42) extending from the inside to the outside of the rotor when viewed along the rotation axis and having a flat plate shape;
A shape that is disposed between the inner end of the first magnet and the inner end of the second magnet and that is convex toward the inside when viewed along the rotation axis. a third magnet (43) having
with
When viewed along the rotation axis, the thickness of the central portion of the third magnet in the circumferential direction of the rotor is smaller than the thicknesses of the first magnet and the second magnet,
rotor (10).
When viewed along the rotation axis, the thickness of both ends of the third magnet in the circumferential direction is equal to the thickness of the first magnet and the second magnet.
A rotor according to claim 1 .
When viewed along the rotation axis, the thickness of the third magnet gradually decreases from both ends toward the center in the circumferential direction.
A rotor according to claim 1 or 2.
when viewed along the axis of rotation, the inner edge and the outer edge of the third magnet are arcs;
The center of the arc that is the inner edge of the third magnet is located outside the center of the arc that is the outer edge of the third magnet,
A rotor according to any one of claims 1 to 3.
The first magnet, the second magnet and the third magnet are ferrite magnets,
A rotor according to any one of claims 1 to 4.
a stator (70);
A rotor according to any one of claims 1 to 5;
comprising a
Motor (100).
A motor comprising the motor according to claim 6,
Compressor (200).
A compressor according to claim 7,
Air conditioner.