Rotating electrical machine, compressor, and refrigeration device

Abstract

A rotor core (32) of a rotating electrical machine (20) has a first core portion (32a) and a second core portion (32b), the second core portion (32b) is adjacent to an end portion of the first core portion (32a) on a first direction side in an axial direction of a rotating shaft, at least a portion of the second core portion (32b) is disposed closer to the first direction side than an end portion of a stator core (22) on the first direction side, and at least a portion of the second core portion (32b) is disposed closer to the second direction side than an end portion of the stator core (22) on the first direction side. The second core section (32b) has a reluctance structure (R) having a lower magnetic permeability than the first core section (32a), and the reluctance structure (R) is formed on the magnetic pole section (S) of the rotor (31) and on the outside in the radial direction of the permanent magnet (33).

Description

Technical Field

[0001] The present disclosure relates to a rotating electrical machine, a compressor and a refrigeration device. Background Art

[0002] The motor described in Patent Document 1 is arranged so that the end surface of the rotor protrudes upward from the end surface of the stator. In this motor, since the height position of the axial center of the rotor is offset upward from the height position of the axial center of the stator, the rotor is urged downward by the magnetic pull. As a result, the up-and-down vibration of the drive shaft disposed below the motor is suppressed.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Publication No. 10-89252 Summary of the invention

[0006] -Technical problem to be solved by the invention-

[0007] However, magnetic flux lines are formed between the rotor and the stator. The higher the density of the magnetic flux lines (magnetic flux density), the stronger the magnetic force, and the performance of the motor (especially the torque performance) is improved. However, so far, no research has been conducted on how to improve the performance of a motor in which the end face of the rotor protrudes axially more than the end face of the stator.

[0008] An object of the present disclosure is to improve the performance of a rotating electric machine in which an end surface of a rotor protrudes axially more than an end surface of a stator.

[0009] -Technical solutions for solving technical problems-

[0010] A first aspect is a rotating electrical machine,

[0011] The rotary electric machine includes a rotor 31 and a stator 21. The rotor 31 includes a rotor core 32 that rotates around a rotation axis O and a plurality of permanent magnets 33 that are arranged in magnet holes formed in the rotor core 32.

[0012] The stator 21 has a stator core 22 arranged radially outside the rotor 31.

[0013] When one direction in the axial direction of the rotation axis O is defined as a first direction and the other direction in the axial direction is defined as a second direction,

[0014] The rotor core 32 includes a first core portion 32a and a second core portion 32b.

[0015] The first core portion 32a is formed such that at least a portion of the first core portion 32a is radially opposed to the stator core 22, and the shapes of the cross sections of the first core portion 32a perpendicular to the axial direction of the rotation axis O are substantially the same.

[0016] The second core portion 32b is formed such that: the second core portion 32b is adjacent to the end portion of the first core portion 32a on the first direction side, and the shapes of the cross sections of the second core portion 32b perpendicular to the axial direction of the rotation axis O are substantially the same,

[0017] The second core portion 32b

[0018] At least a portion is arranged at a position closer to the first direction side than the end of the stator core 22 on the first direction side, and the second core portion 32b has a magnetic resistance structure R with a lower magnetic permeability than the first core portion 32a,

[0019] The magnetic resistance structure R is formed at the magnetic pole portion S of the rotor 31 and radially outside the permanent magnet 33 .

[0020] In the first aspect, the magnetic flux lines extending from the permanent magnets 33 facing each other in the circumferential direction of the rotor 31 are guided to the stator core 22 via the first core portion 32a due to the magnetic resistance structure R. As a result, since the magnetic flux of the portion of the second core portion 32b that is not radially facing the stator 21 is concentrated on the first core portion 32a, the in-plane eddy current generated in the stator core 22 due to the axial magnetic flux from the second core portion 32b toward the stator core 22 is suppressed, and the reduction of the magnetic force can be suppressed. As a result, the reduction of the performance of the rotating electric machine can be suppressed.

[0021] The second aspect is based on the first aspect.

[0022] The center position of the rotor core 32 in the axial direction is offset to the first direction side relative to the center position of the stator core 22 in the axial direction.

[0023] In the second aspect, by shifting the axial center position of the rotor core 32 toward the second core portion 32 b relative to the axial center position of the stator core 22 , a force (tensile force) biasing the rotor 31 in the second direction can be generated.

[0024] The third aspect is based on the second aspect.

[0025] The end of the first core portion 32a on the first direction side is offset toward the first direction side relative to the end of the stator core 22 on the first direction side, and

[0026] An end portion of the first core portion 32 a on the second direction side is offset toward the first direction relative to an end portion of the stator core 22 on the second direction side.

[0027] In the third aspect, a pulling force that urges the rotor 31 toward the second direction can be generated at both ends of the rotor 31 in the direction of the rotation axis O.

[0028] According to a fourth aspect, based on any one of the first to third aspects,

[0029] The rotating electric machine also includes a third core portion 32c, which has the magnetic resistance structure R, and is adjacent to the end of the first core portion 32a on the second direction side, and the third core portion 32c is formed to have a shape that is substantially the same as a cross-section of the third core portion 32c that is perpendicular to the axial direction of the rotating axis O.

[0030] In the fourth aspect, since the second core portion 32b and the third core portion 32c having the magnetic resistance structure R are arranged at both axial ends of the first core portion 32a, the performance degradation of the rotating motor can be suppressed compared to the case where only the second core portion 32b is arranged, and the pulling force applied to the rotor 31 toward the second direction side can be enhanced.

[0031] The fifth aspect is based on the fourth aspect.

[0032] The end of the first core portion 32a on the first direction side is offset toward the first direction side relative to the end of the stator core 22 on the first direction side.

[0033] The end of the first core portion 32a on the second direction side is offset toward the first direction side relative to the end of the stator core 22 on the second direction side, and

[0034] A portion of the third core portion 32 c is disposed closer to the second direction side than an end portion of the stator core 22 on the second direction side.

[0035] In the fifth aspect, by providing the magnetic resistance structure R at both ends of the rotor core 32, the axial length of the rotor core 32, i.e., the stacking thickness, can be increased, thereby obtaining a strong magnetic force. In addition, since the pulling force generated at both axial ends of the rotor 31 is generated toward the second direction side, sufficient pulling force can be obtained.

[0036] According to the sixth aspect, based on any one of the first to fifth aspects,

[0037] The magnetic resistance structure R is a gap R formed on the rotor core 32 .

[0038] In the sixth aspect, the magnetic resistance structure R can be easily provided simply by forming the gap R in the rotor core 32 .

[0039] The seventh aspect is based on the sixth aspect.

[0040] When the rotor 31 is viewed from the direction of the rotation axis O, the rotor core 32 is formed so that the shapes of the outer peripheral ends of the cross section perpendicular to the axial direction are all the same.

[0041] In the seventh aspect, the outer peripheral surface of the rotor core 32 can be formed into a smooth surface. This can reduce the flow resistance of the fluid flowing in the axial direction between the stator core 22 and the rotor core 32 .

[0042] The eighth aspect is based on any one of the first to seventh aspects,

[0043] The magnetic resistance structure R is formed by cutting off the outer peripheral end of the rotor core 32 in the axial direction.

[0044] In the eighth aspect, the magnetic resistance structure R can be easily provided simply by cutting off the outer peripheral end of the rotor core 32. By cutting off the rotor core 32 to a large extent, the magnetic permeability of the magnetic resistance structure R can be reduced.

[0045] A ninth aspect is based on any one of the first to eighth aspects,

[0046] The axial length of the first core portion 32 a is the same as the axial length of the stator core 22 .

[0047] In the ninth aspect as well, the same effects as those of the first aspect can be obtained.

[0048] The tenth aspect is based on any one of the first to ninth aspects,

[0049] The permanent magnet 33 is a ferrite magnet.

[0050] In the tenth aspect, since the magnetic force of the ferrite magnet is relatively weak, the magnetic force can be strengthened by increasing the stacking thickness of the rotor 31. However, when the stacking thickness of the rotor 31 is increased, the rotating electric machine will be larger. However, by using the magnetic resistance structure R, the reduction in the magnetic force of the rotating electric machine can be suppressed while suppressing the stacking thickness of the rotor 31.

[0051] The eleventh aspect is based on any one of the first to tenth aspects,

[0052] The plurality of permanent magnets 33 are arranged in the circumferential direction of the rotor core 32 and are disposed to penetrate the rotor core 32 in the axial direction.

[0053] The permanent magnets 33 have the same cross-sectional shape perpendicular to the axial direction.

[0054] In the eleventh aspect, there is no need to shorten or lengthen a portion of the permanent magnet 33 according to the shape of the rotor 31, and the permanent magnet 33 can be easily disposed in the rotor.

[0055] A twelfth aspect is a compressor including the rotary electric machine according to any one of the first to eleventh aspects, and a compression mechanism (50) driven by the rotary electric machine.

[0056] In the twelfth aspect, there can be provided a compressor including the rotating electrical machine according to any one of the first to eleventh aspects and a compression mechanism (50).

[0057] The thirteenth aspect is a refrigeration device comprising the compressor according to the twelfth aspect.

[0058] In a thirteenth aspect, there can be provided a refrigeration device including the compressor according to the twelfth aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 is a simplified structural diagram of a refrigeration device involved in an embodiment;

[0060] Figure 2 is a longitudinal cross-sectional view of the compressor according to the embodiment, corresponding to a cross section parallel to the axial direction;

[0061] Figure 3 is a diagram of the motor viewed from the axial direction;

[0062] Figure 4 is a perspective view showing a portion of a longitudinal section of a rotor;

[0063] Figure 5 is a schematic diagram showing a longitudinal section of an example of a conventional rotating electrical machine;

[0064] Figure 6 is equivalent to Figure 5 , which shows a rotating electrical machine with an increased lamination thickness of the rotor;

[0065] Figure 7 is a cutaway perspective view of a portion of an electric motor;

[0066] Figure 8 1 is a diagram showing the region of the magnetic pole portion and the region radially outside the permanent magnet as viewed from the axial direction;

[0067] Fig. 9 is a diagram for explaining magnetic flux generated in a motor; Fig. 9 (A) is a diagram of a portion of a rotor viewed from the axial direction; Fig. 9 (B) is a diagram showing a portion of a longitudinal section of a rotating electrical machine;

[0068] Fig.10 is a perspective view showing a portion of a rotor according to another embodiment;

[0069] Fig.11 is a plan view showing the shape of a permanent magnet according to another embodiment;

[0070] Fig.12 It is a plan view showing the shape of a permanent magnet according to another embodiment. DETAILED DESCRIPTION

[0071] The following describes the embodiments of the present invention with reference to the accompanying drawings. It should be noted that the following embodiments are essentially preferred examples and are not intended to limit the scope of the present invention, its application objects or its use. The various structures of the various embodiments, modifications, other examples, etc. described below can be combined or partially replaced within the scope of the present invention. In addition, in the drawings described below, a portion of the shadow representing the cross section is sometimes omitted.

[0072] (1) Refrigeration equipment

[0073] like Figure 1 As shown, the refrigeration device 1 of the present embodiment is an air conditioner. The air conditioner 1 can be a dedicated refrigeration machine or a dedicated heating machine. The refrigeration device 1 has a refrigerant circuit 1a filled with a refrigerant. The refrigerant circuit 1a has a compressor 10, a heat radiator 2, an expansion valve 3 and an evaporator 4. The refrigerant circuit 1a performs a vapor compression refrigeration cycle. In addition, the air conditioner 1 can also be an air conditioner that switches between cooling and heating. In this case, the air conditioner has a switching mechanism (such as a four-way reversing valve) that switches the circulation direction of the refrigerant.

[0074] In the refrigeration cycle, the refrigerant compressed by the compressor 10 releases heat to the air in the radiator 2. The refrigerant after releasing heat is decompressed by the expansion valve 3 and evaporates in the evaporator 4. The evaporated refrigerant is sucked into the compressor 10 (see Figure 1 ).

[0075] (2) Compressor

[0076] like Figure 2 As shown in FIG. 1 , the compressor 10 of the present embodiment is a rotary compressor. The compressor 10 includes a housing 11, a motor 20, a drive shaft 40, and a compression mechanism 50. In the following description, “upper”, “lower”, “right”, and “left” refer to directions when the compressor 10 is viewed from the front (see FIG. 1 ). Figure 2). Specifically, "up" and "down" are also the axial direction of the drive shaft 40. "Right" and "left" are directions orthogonal to the axial direction and are also radial directions of the motor 20 (or housing 11). In addition, in the following description, the upper direction is sometimes referred to as the first direction, and the lower direction is sometimes referred to as the second direction.

[0077] (2-1) Shell

[0078] The shell (11) is a fully closed container. The high-pressure refrigerant discharged from the compression mechanism (50) fills the inside of the shell (11).

[0079] The housing 11 is made of a metal material. The housing 11 has a trunk 12, a bottom 13, and a top 14. The trunk 12 is a cylindrical member extending in the up-down direction. The cylindrical axis direction of the trunk 12 is vertical. The bottom 13 closes the lower end of the trunk 12, and the top 14 closes the upper end of the trunk 12.

[0080] The housing 11 accommodates the motor 20, the drive shaft 40, and the compression mechanism 50. The motor 20, the drive shaft 40, and the compression mechanism 50 are arranged in order from top to bottom in the housing 11.

[0081] (2-2) Electric motor

[0082] like Figure 2 and Figure 3 As shown, the motor 20 has a stator 21 and a rotor 31. The rotation speed of the motor 20 is controlled by an inverter. In other words, the compressor 10 is an inverter compressor with a variable rotation speed. The motor 20 is an example of a rotary electric machine 20.

[0083] The stator 21 is fixed to the inner circumferential surface of the trunk 12. The stator 21 has a stator core 22. The stator core 22 is arranged radially outside the rotor 31. The stator core 22 is formed by stacking a plurality of electromagnetic steel plates in the axial direction. The stator core 22 has an annular back yoke 24 and teeth 25. Six core cutouts 26 are formed on the outer circumferential surface of the back yoke 24. The core cutouts 26 are grooves extending in the axial direction of the stator core 22. The teeth 25 extend radially inward from the inner circumferential surface of the back yoke 24. In the present embodiment, the six teeth 25 are arranged at equal intervals in the circumferential direction (specifically, at intervals of 60°). The stator 21 has a coil 23. The coil 23 is wound around the teeth 25 (refer to Figure 2 ).

[0084] like Figure 3 and Figure 4As shown, the rotor 31 includes a rotor core 32, a plurality of permanent magnets 33, and a magnetic resistance structure R. The magnetic resistance structure R will be described later. The rotor core 32 rotates around the rotation axis O. The rotor core 32 is arranged on the inner side of the stator 21. In the following description, the direction in which the rotation axis O extends is sometimes referred to as the axial direction. In addition, the circumferential direction is the outer peripheral direction of the rotor core 32 when the rotor core 32 is viewed from the axial direction.

[0085] A plurality of permanent magnets 33 are arranged inside the rotor core 32. The permanent magnets 33 of the present embodiment are ferrite magnets. The permanent magnets 33 are arranged inside slots 34 formed in the rotor core 32. The slots 34 are formed to penetrate the rotor core 32 in the axial direction. The plurality of slots 34 are formed to extend radially from the center of the rotation axis O toward the radially outer side when viewed from the axial direction. Specifically, six slots 34 formed in a V shape when viewed from above are arranged at equal intervals in the circumferential direction of the rotor 31.

[0086] The permanent magnet 33 is disposed in each of the six slots 34. That is, the rotor 31 of the present embodiment has six permanent magnets 33. The six permanent magnets 33 are arranged in the circumferential direction of the rotor core 32 and are disposed so as to penetrate the rotor core 32 in the axial direction. The cross-sectional shapes of the permanent magnets 33 perpendicular to the axial direction are the same (see FIG. Figure 4 ).

[0087] When viewed from the axial direction, the permanent magnet 33 is configured to be V-shaped in a manner embedded in the groove 34. Specifically, the permanent magnet 33 includes a first magnet portion 33a that is V-shaped when viewed from the axial direction, and a second magnet portion 33b and a third magnet portion 33c that extend radially outward from the ends of the first magnet portion 33a. When viewed from the axial direction, the second magnet portion 33b and the third magnet portion 33c extend linearly to the vicinity of the outer peripheral end of the rotor 31. The second magnet portion 33b and the third magnet portion 33c are adjacent to each other in the circumferential direction of the rotor 31.

[0088] (2-3) Drive shaft

[0089] like Figure 2 As shown, the drive shaft 40 is fixed to the center of the rotation axis O of the rotor 31. The drive shaft 40 extends downward from the motor 20. The drive shaft 40 is driven to rotate by the motor 20. The drive shaft 40 is rotatably supported by a bearing 41 provided below.

[0090] (2-4) Compression mechanism

[0091] The compression mechanism 50 includes a cylinder 51 and a piston 52 disposed inside the cylinder 51. A cylinder chamber 53 is formed between the inner peripheral surface of the cylinder 51 and the outer peripheral surface of the piston 52. In the cylinder chamber 53, the piston 52 driven by the drive shaft 40 compresses the fluid.

[0092] (2-5) Suction pipe and discharge pipe

[0093] The compressor 10 has a suction pipe 15 and a discharge pipe 16. The suction pipe 15 penetrates the trunk 12 in the radial direction and communicates with the cylinder chamber 53. The low-pressure refrigerant in the refrigerant circuit 1a is sucked into the cylinder chamber 53 via the suction pipe 15. The discharge pipe 16 penetrates the top 14 in the axial direction and communicates with the internal space of the shell 11. The refrigerant compressed in the compression mechanism 50 flows through the core cutout 26 of the motor 20 and the like, and is then sent to the refrigerant circuit 1a from the discharge pipe 16.

[0094] (3) Technical issues of electric motors with permanent magnets having low magnetic force

[0095] From the perspective of the manufacturing cost of the motor, it is preferable to use relatively low-priced ferrite magnets in the motor. However, since the magnetic force of the ferrite magnet is relatively low, in order to make the motor exert the specified performance, it is necessary to increase the surface area of ​​the ferrite magnets provided in the rotor core. For example, the surface area of ​​the ferrite magnets can be increased by increasing the axial thickness of the rotor.

[0096] Here, in a rotary compressor such as the present embodiment, it is required to suppress abnormal noise from the compression mechanism caused by the up and down vibration of the drive shaft driven by the motor. In view of this problem, if the drive shaft is forced downward, the thrust acts strongly on the lower bearing, thereby suppressing the up and down vibration of the drive shaft. As such a method of applying force downward to the drive shaft, it is considered to utilize the pulling force acting between the rotor and the stator. That is, by arranging the rotor core to protrude axially upward than the stator core, a pulling force that pulls the rotor core downward is generated.

[0097] Specifically, if Figure 5 As shown in FIG. 1 , when the axial lengths of the rotor core and the stator core are the same, the height position of the axial center of the rotor core (hereinafter referred to as the magnet center (MC)) is shifted upward relative to the magnet center of the stator core, thereby generating a tensile force between the upper end of the stator core and the upper end of the rotor core, and between the lower end of the stator core and the lower end of the rotor core. Under the action of this tensile force, the rotor core is forced downward (see FIG. 1 ). Figure 5 ), so that the drive shaft connected to the motor is pressed against the bearing arranged below. As a result, the up and down vibration of the drive shaft is suppressed.

[0098] However, if Figure 6As shown in FIG. 1 , when the axial length of the rotor core is increased in order to increase the surface area of ​​the permanent magnet, if the lower end of the rotor core protrudes downward more than the lower end of the stator core, a pulling force that pushes the rotor core upward is generated between the lower end portion of the stator core and the lower end portion of the rotor core. Therefore, even if the position of the magnet center of the rotor core and the position of the magnet center of the stator core are offset from each other, the pulling force (force that pushes the rotor downward) acting between the upper end portion of the stator core and the upper end portion of the rotor core is reduced by the pulling force (force that pushes the rotor upward) acting between the lower end portion of the stator core and the lower end portion of the rotor core (refer to FIG. 1 ). Figure 6 ), so the effect of suppressing the vertical vibration of the drive shaft is reduced.

[0099] To address this problem, the magnet center of the rotor core is greatly offset upward relative to the magnet center of the stator core, thereby enabling sufficient pulling force to be applied downward to the rotor. However, if the area where the stator core is not opposite to the rotor core also increases, the magnetic flux density between the stator core and the rotor core decreases, and the performance of the motor (especially the torque performance) may decrease. In addition, when the magnet center of the stator core is farther away from the magnet center of the rotor core, the overall axial length of the motor becomes longer, resulting in a larger motor.

[0100] In order to solve such a technical problem, a magnetic resistance structure R is provided on the rotor core 32 of the motor 20 in the present embodiment. The magnetic resistance structure R can suppress the performance degradation of the motor 20 and can generate sufficient downward pulling force on the rotor 31. The rotor core 32 and the magnetic resistance structure R of the present embodiment are described in detail below.

[0101] (4) First core portion, second core portion, and third core portion

[0102] like Figure 4 and Figure 7 As shown, the rotor core 32 of this embodiment is composed of a first core portion 32a, a second core portion 32b and a third core portion 32c, each of which is formed in a substantially cylindrical shape. The second core portion 32b, the first core portion 32a and the third core portion 32c are arranged in order from top to bottom.

[0103] The first core portion 32a is formed such that at least a portion of the first core portion 32a is opposite to the stator core 22 in the radial direction, and the first core portion 32a has the same cross-sectional shape perpendicular to the axial direction of the rotation axis O. The axial length (up and down direction) D1 of the first core portion 32a is the same as the axial length (up and down direction) D2 of the stator core 22. The upper side end of the first core portion 32a is offset upward from the upper side end of the stator core 22. The lower side end of the first core portion 32a is offset upward from the lower side end of the stator core 22.

[0104] The second core portion 32b is adjacent to the upper end of the first core portion 32a. The second core portion 32b is arranged above the upper end of the stator core 22. That is, the second core portion 32b protrudes upward from the upper end of the stator core 22.

[0105] The third core portion 32c is adjacent to the lower end of the first core portion 32a. A portion of the third core portion 32c is arranged below the lower end of the stator core 22. In other words, a portion of the third core portion 32c protrudes downward from the lower end of the stator core 22.

[0106] Thus, the axial length of the rotor core 32 is longer than the axial length of the stator core 22. The axial center position (magnet center) of the rotor core 32 is offset upward from the axial center position (magnet center) of the stator core 22.

[0107] The first core portion 32a, the second core portion 32b, and the third core portion 32c are each formed to have the same or substantially the same cross-sectional shape perpendicular to the axial direction of the rotation axis O. Substantially the same refers to a range of degrees caused by deviations during manufacture of the rotor core 32, the provision of skew (skewed slots) on the rotor 31, or relatively minor differences that have a relatively small effect on motor characteristics.

[0108] The first core portion 32a and the second core portion 32b have the same or substantially the same cross-section shape except for the magnetoresistive structure R. The first core portion 32a and the third core portion 32c have the same or substantially the same cross-section shape except for the magnetoresistive structure R.

[0109] On the outer circumferential surface of the rotor core 32, the first core portion 32a is smoothly connected to the second core portion 32b, and the first core portion 32a is smoothly connected to the third core portion 32c. In other words, the outer circumferential surface of the first core portion 32a is connected to the outer circumferential surface of the second core portion 32b approximately flush, and the outer circumferential surface of the first core portion 32a is connected to the outer circumferential surface of the third core portion 32c approximately flush. In this way, the rotor core 32 is formed so that when the rotor 31 is viewed from the direction of the rotation axis O, the shape of the axial section of the rotor core 32 is the same.

[0110] (5) Magnetoresistive structure

[0111] The magnetic resistance structure R is provided on the second core portion 32b and the third core portion 32c. The magnetic resistance structure R is a structure having a lower magnetic permeability than the first core portion 32a. The second core portion 32b and the third core portion 32c are formed in the same shape. Since the magnetic resistance structures R formed on the second core portion 32b and the third core portion 32c are also the same, the magnetic resistance structure R of the second core portion 32b will be described below, and the description of the magnetic resistance structure R of the third core portion 32c will be omitted.

[0112] like Figure 8 As shown, the magnetic resistance structure R of the present embodiment is formed on the magnetic pole portion S of the rotor 31 and radially outside the permanent magnet 33 .

[0113] Specifically, the magnetic pole portion S formed on the permanent magnet 33 of the rotor 31 of the present embodiment is a region of the permanent magnet 33 that faces each other in the circumferential direction and its surrounding region (including the permanent magnet 33) when viewed from the axial direction ( Figure 8 The magnetic resistance structure R of this embodiment is provided in the radially outer region ( Figure 8 at least a portion of the area (the shaded area).

[0114] like Figure 3 , Figure 4 as well as Figure 7 As shown, the magnetic resistance structure R of the present embodiment is a gap R formed on the rotor core 32. The gap R is formed in a region radially outward of a line connecting the radially outer ends of the second magnet portion 33b and the third magnet portion 33c of each permanent magnet 33. The gap R is formed along the outer peripheral surface of the second core portion 32b and the third core portion 32c. When viewed from the axial direction, six such gaps R are formed in the rotating electric machine 20 of the present embodiment.

[0115] The gap R of this embodiment is a through hole that passes through the upper and lower ends of the second core portion 32b and the third core portion 32c. In other words, the lower end of the gap R of the second core portion 32b is connected to the upper end of the first core portion 32a, and the upper end of the gap R of the third core portion 32c is connected to the lower end of the first core portion 32a.

[0116] (6) Features

[0117] (6-1) Feature 1

[0118] At least a portion of the second core portion 32b of the rotor core 32 is arranged above the upper end of the stator core 22, and the second core portion 32b of the rotor core 32 has a magnetic resistance structure R having a lower magnetic permeability than the first core portion 32a. The magnetic resistance structure R is formed at the magnetic pole portion S of the rotor 31 and radially outside the permanent magnet 33.

[0119] Here, if Fig. 9 As shown in (A), when the rotor 31 is viewed from above, the circumferentially opposing surfaces of the second magnet portion 33b and the third magnet portion 33c of the permanent magnet 33 have the same polarity, so the magnet flux extending in the directions opposing each other in the circumferential direction is directed radially outward.

[0120] like Fig. 9 As shown in (B), when the magnetic resistance structure R is not provided on the second core portion 32b, the magnet flux extends in the direction indicated by the dotted arrow. However, since the magnetic resistance structure R is provided in the area of ​​the second core portion 32b that blocks the magnet flux from flowing toward the radial outer side of the permanent magnet 33, the magnet flux from the permanent magnet 33 extends toward the first core portion 32a in a manner bypassing the magnetic resistance structure R.

[0121] In this way, the magnetic flux of the second core portion 32b is guided to the stator core 22 via the first core portion 32a. As a result, the magnetic flux of the portion of the second core portion 32b that is not opposite to the stator core 22 is concentrated toward the first core portion 32a, and as a result, the reduction in the magnetic force between the rotor 31 and the stator 21 can be suppressed, thereby suppressing the reduction in the performance of the rotating electric machine 20.

[0122] (6-2) Feature 2

[0123] The axial center position of the rotor core 32 is offset upward from the axial center position of the stator core 22. In other words, the magnet center of the rotor core 32 is offset upward from the magnet center of the stator core 22, that is, in the first direction.

[0124] In this way, by shifting the magnet center of the rotor core 32 toward the second core portion 32b relative to the magnet center of the stator core 22, downward pulling force can be generated on the rotor 31. As a result, thrust acts on the bearing below, suppressing the vertical vibration of the drive shaft 40, and as a result, abnormal noise can be reduced.

[0125] (6-3) Feature 3

[0126] The upper end of the first core portion 32 a is offset upward from the upper end of the stator core 22 , and the lower end of the first core portion 32 a is offset upward from the lower end of the stator core 22 .

[0127] In this way, since a pulling force is generated to bias both axial ends of the rotor 31 downward, a thrust force can be reliably applied to the bearings below.

[0128] (6-4) Feature 4

[0129] The motor 20 also includes a third core portion 32c, which has a magnetic resistance structure R and is formed as follows: the third core portion 32c is adjacent to the end portion on the lower side of the first core portion 32a, and the shape of the cross-section of the third core portion 32c perpendicular to the axial direction of the rotation axis O is substantially the same.

[0130] In this way, since the magnetic resistance structure R is provided at both axial ends of the rotor 31, the stacking thickness of the rotor 31 can be increased not only upward but also downward. As a result, the surface area of ​​the permanent magnet 33 can be increased to obtain a strong magnetic force, and the size of the motor can be suppressed from increasing.

[0131] (6-5) Feature 5

[0132] The end of the upper side of the first core portion 32a is offset upward compared to the end of the upper side of the stator core 22, the end of the lower side of the first core portion 32a is offset upward compared to the end of the lower side of the stator core 22, and a portion of the third core portion 32c is arranged at a position lower than the end of the lower side of the stator core 22.

[0133] In this way, since a downward pulling force acts on the upper and lower parts of the rotor 31, the force for suppressing the vertical vibration of the drive shaft can be increased. In this way, in addition to the effect of the above-mentioned feature 4, the generation of abnormal noise can be reliably suppressed.

[0134] (6-6) Feature 6

[0135] The magnetic resistance structure R is a gap R formed in the rotor core 32. The magnetic resistance structure R can be easily provided by simply forming the gap R in the rotor core 32. In the present embodiment, the gap R is formed in a region radially outward of a line connecting the radially outer ends of the second magnet portion 33b and the third magnet portion 33c. The gap R is formed along the outer peripheral surface of the second core portion 32b and the third core portion 32c.

[0136] (6-7) Feature 7

[0137] The rotor core 32 is formed such that when the rotor 31 is viewed from the direction of the rotation axis O, the outer peripheral ends of the rotor core 32 in a cross section perpendicular to the axial direction have the same shape. The outer peripheral surface of the rotor core 32 is formed as a smooth surface. Thus, the flow resistance of the refrigerant flowing in the space (air gap) between the stator core 22 and the rotor core 32 can be reduced.

[0138] (6-8) Feature 8

[0139] The permanent magnet 33 is a ferrite magnet. Since the magnetic force of the ferrite magnet is relatively weak, although the magnetic force can be enhanced by increasing the stacking thickness of the rotor 31, the motor 20 will be enlarged due to the increase in the stacking thickness of the rotor 31. However, by providing the magnetic resistance structure R, the magnetic force can be enhanced even without increasing the stacking thickness of the rotor 31, so the enlargement of the motor 20 can be suppressed.

[0140] (6-9) Feature 9

[0141] The plurality of permanent magnets 33 are arranged in the circumferential direction of the rotor core 32 and are arranged to penetrate the rotor core 32 in the axial direction, and the cross-sectional shapes perpendicular to the axial direction of each permanent magnet 33 are all the same. Thus, the permanent magnets 33 can be easily arranged in the rotor without shortening or lengthening a part of the permanent magnets 33 according to the shape of the rotor core 32.

[0142] (7) Other Implementation Methods

[0143] The above-mentioned embodiment may also adopt the following structure.

[0144] like Fig.10 As shown, the magnetic resistance structure R may also be formed by cutting off the outer peripheral end of the rotor core 32 in the axial direction. The magnetic resistance structure R can be easily provided by simply cutting off the outer peripheral end of the rotor core 32. In addition, since the volume of the space can be made larger than the gap R in the above-mentioned embodiment, the magnetic permeability can be reduced accordingly. As a result, the magnetic flux is further concentrated from the second core portion 32b and the third core portion 32c to the first core portion 32a, and the performance degradation of the motor 20 can be suppressed.

[0145] The second core portion 32b and the third core portion 32c may not have the same shape. Specifically, the second core portion 32b may be formed to be longer or shorter than the third core portion 32c in the axial direction. In addition, the structure or shape of the magnetic resistance structure R provided on the second core portion 32b and the third core portion 32c may also be different.

[0146] like Fig.11 As shown in FIG. 1 , the permanent magnet 33 provided in the rotor 31 may also be a magnet without the first magnet portion 33a when viewed from the axial direction. In this case, the magnetic resistance structure R only needs to be provided in the magnetic pole portion S of the rotor 31 and include the first region ( Fig.11 The vertical line area), or the second area other than the first area formed by the magnetic pole portion S of the rotor 31 and the second magnet portion 33b and the third magnet portion 33c facing each other in the circumferential direction ( Fig.11 )

[0147] like Fig.12 As shown, the permanent magnet 33 provided on the rotor 31 may not have the first magnet when viewed from the axial direction, and the second magnet portion 33b and the third magnet portion 33c may be integrated. In this case, the magnetic pole portion S is Fig.12 The magnetic resistance structure R is provided in the magnetic pole portion S of the rotor 31 and includes the first area ( Fig.12 The vertical line area), or the second area other than the first area formed by the magnetic pole portion S of the rotor 31 and the second magnet portion 33b and the third magnet portion 33c facing each other in the circumferential direction ( Fig.12 )

[0148] The magnetic resistance structure R only needs to be provided in a region of the rotor core 32 that blocks the flow of magnet flux toward the radially outer side of the permanent magnet 33. For example, the magnetic resistance structure R may be provided in a region between circumferentially adjacent permanent magnets having the same polarity or in a region radially outward of such a region.

[0149] In addition, the magnetic resistance structure R can also be set in the area between the radial outer ends of the permanent magnets (equivalent to the second magnet portion 33b and the third magnet portion 33c of the above-mentioned embodiment) arranged adjacent to each other in the circumferential direction of the rotor core 32 across the magnetic pole center line when observing the rotor 31 from the axial direction, or in the area radially outside of this area.

[0150] In addition, the permanent magnet 33 may also be divided into a plurality of parts. For example, the permanent magnet 33 of the above embodiment may also be divided into a first magnet part 33a, a second magnet part 33b, and a third magnet part 33c. In such a collection of permanent magnets 33, the magnetic resistance structure R may also be provided in a region sandwiched by the permanent magnets 33 arranged at both ends of the circumferential direction in the collection of permanent magnets 33 arranged at the magnetic pole part S of the rotor 31 when the rotor 31 is viewed from the axial direction, or in a region radially outside of the region.

[0151] In addition, the magnetic resistance structure R may be formed to be orthogonal to the flow direction of the magnet magnetic flux toward the radially outer side of the first core portion 32a.

[0152] The shapes of the magnetoresistance structure R of the second core portion 32b and the magnetoresistance structure R of the third core portion 32c may also be different. For example, when the structure of the magnetoresistance structure R is a gap R, the shape of the gap R when viewed from the axial direction may also be different between the second core portion 32b and the third core portion 32c.

[0153] The electric motor 20 only needs to include the second core portion 32 b and may not include the third core portion 32 c .

[0154] The farther the magnet center of the rotor core 32 is from the magnet center of the stator core 22 , the stronger the pulling force can be obtained by utilizing the rotor core 32 . Therefore, the rotor core 32 and the stator core 22 may be arranged so that the magnet centers are farther from each other.

[0155] The above embodiments and variations are described, but it should be understood that various changes can be made to the form and specific circumstances without departing from the subject matter and scope of the claims. As long as the functions of the objects of the present disclosure are not affected, the above embodiments and variations can also be appropriately combined and replaced. The words "first", "second"... mentioned above are only used to distinguish the sentences containing the above words, and are not intended to limit the number and order of the sentences.

[0156] - Industrial Applicability -

[0157] In summary, the present disclosure is useful for rotating electrical machines, compressors, and refrigeration devices.

[0158] - Explanation of symbols -

[0159] 1 Refrigeration unit

[0160] 10Compressor

[0161] 20 Electric motor (rotating motor)

[0162] 21 stator

[0163] 22 stator core

[0164] 31 rotor

[0165] 32 rotor core

[0166] 32a First core portion

[0167] 32b Second core part

[0168] 32c Third core part

[0169] 33 Permanent magnet

[0170] 50 compression mechanism

[0171] ORotation axis

[0172] R magnetoresistance structure (gap)

Claims

1. A rotating electric machine, comprising a rotor (31) and a stator (21), wherein the rotor (31) has a rotor core (32) rotating about a rotating axis (O) and a plurality of permanent magnets (33) arranged in magnet holes formed in the rotor core (32), and the stator (21) has a stator core (22) arranged radially outside the rotor (31), characterized in that: When one direction in the axial direction of the rotation axis (O) is defined as a first direction and the other direction in the axial direction is defined as a second direction, The rotor core (32) comprises a first core portion (32a) and a second core portion (32b). The first core portion (32a) is formed such that at least a portion of the first core portion (32a) is radially opposed to the stator core (22), and the shapes of the cross sections of the first core portion (32a) perpendicular to the axial direction of the rotating shaft (O) are substantially the same. The second core portion (32b) is formed such that: the second core portion (32b) is adjacent to the end portion of the first core portion (32a) on the first direction side, and the shapes of the cross sections of the second core portion (32b) perpendicular to the axial direction of the rotation axis (O) are substantially the same, At least a portion of the second core portion (32b) is arranged closer to the first direction side than an end portion of the stator core (22) on the first direction side, and The second core portion (32b) has a magnetic resistance structure (R) having a lower magnetic permeability than the first core portion (32a), The magnetic resistance structure (R) is formed at the magnetic pole portion (S) of the rotor (31) and radially outside the permanent magnet (33).

2. The rotating electrical machine according to claim 1, characterized in that: The center position of the rotor core (32) in the axial direction is offset toward the first direction relative to the center position of the stator core (22) in the axial direction.

3. The rotating electrical machine according to claim 2, characterized in that: The end of the first core portion (32a) on the first direction side is offset toward the first direction side relative to the end of the stator core (22) on the first direction side, and An end portion of the first core portion (32a) on the second direction side is offset toward the first direction relative to an end portion of the stator core (22) on the second direction side.

4. The rotating electrical machine according to any one of claims 1 to 3, characterized in that: The rotating electric machine also includes a third core portion (32c), the third core portion (32c) having the magnetic resistance structure (R), and the third core portion (32c) is adjacent to the end of the first core portion (32a) on the second direction side, and the third core portion (32c) is formed to have a shape that is substantially the same as a cross-section of the third core portion (32c) perpendicular to the axial direction of the rotating shaft (O).

5. The rotating electrical machine according to claim 4, characterized in that: The end of the first core portion (32a) on the first direction side is offset toward the first direction side relative to the end of the stator core (22) on the first direction side. The end of the first core portion (32a) on the second direction side is offset toward the first direction side relative to the end of the stator core (22) on the second direction side, and A portion of the third core portion (32c) is arranged closer to the second direction side than an end portion of the stator core (22) on the second direction side.

6. The rotating electrical machine according to any one of claims 1 to 5, characterized in that: The magnetic resistance structure (R) is a gap (R) formed on the rotor core (32).

7. The rotating electrical machine according to claim 6, characterized in that: When the rotor (31) is viewed from the direction of the rotation axis (O), the rotor core (32) is formed so that the shapes of the outer peripheral ends of the cross section perpendicular to the axial direction are all the same.

8. The rotating electrical machine according to any one of claims 1 to 7, characterized in that: The magnetic resistance structure (R) is formed by cutting off the outer peripheral end of the rotor core (32) in the axial direction.

9. The rotating electrical machine according to any one of claims 1 to 8, characterized in that: The axial length of the first core portion (32a) is the same as the axial length of the stator core (22).

10. The rotating electrical machine according to any one of claims 1 to 9, characterized in that: The permanent magnet (33) is a ferrite magnet.

11. The rotating electrical machine according to any one of claims 1 to 10, characterized in that: The plurality of permanent magnets (33) are arranged in the circumferential direction of the rotor core (32) and are arranged to penetrate the rotor core (32) in the axial direction. The cross-sectional shapes of the permanent magnets (33) perpendicular to the axial direction are the same.

12. A compressor, characterized in that: The compressor includes the rotary electric machine according to any one of claims 1 to 11, and a compression mechanism (50) driven by the rotary electric machine.

13. A refrigeration device, characterized in that: The refrigeration device comprises the compressor according to claim 12.

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