Rotor structure, electric machine and compressor

Abstract

The main purpose of the present application is to provide a rotor structure, a motor and a compressor, wherein the rotor structure comprises a rotor core and a plurality of permanent magnets arranged on the rotor core to form a plurality of magnetic poles on the rotor core, the plurality of magnetic poles comprising a plurality of N poles and a plurality of S poles arranged alternately along the circumferential direction of the rotor core; at least one magnetic pole of the rotor core is provided with a magnetic isolation hole, the magnetic isolation hole comprises a first hole body part and a second hole body part which are in communication with each other; wherein a plane perpendicular to the axis of the rotor core is a predetermined plane, the projection of the first hole body part on the predetermined plane is a strip-shaped and its extension direction is arranged to cross the circumferential direction of the rotor core, and the projection of the second hole body part on the predetermined plane is a strip-shaped and arranged to cross the projection of the first hole body part on the predetermined plane. Through the technical scheme of the present application, the problem of large vibration noise of the motor in the prior art is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of electric machines, in particular to a rotor structure, an electric machine and a compressor. BACKGROUND

[0002] In recent years, with the development of permanent magnet material manufacturing technology and rapid cost reduction, the excellent performance and low price of permanent magnet material greatly promote the development of permanent magnet motor technology, and the rich resources of permanent magnet material promote the research and development of permanent magnet motor technology.

[0003] Permanent magnet motor relies on permanent magnet to generate main magnetic field. Compared with ordinary induction motor, permanent magnet synchronous motor does not need reactive excitation current, and the rotor resistance loss is zero in synchronous operation state. Therefore, it has the characteristics of high power factor and high efficiency, and can be used to replace induction motor with low power index, and the economic and social benefits are very significant, and it is widely used in various industries.

[0004] However, the permanent magnet material of the permanent magnet synchronous motor, the permanent magnet with fixed grade and material has constant magnetic energy product, and the air gap magnetic field of the motor is difficult to adjust. At the same time, the tooth structure of the motor makes the air gap magnetic density and the harmonic content of back electromotive force larger, and the peak value of electromagnetic force density of the motor is large, so that the motor torque ripple and vibration noise are large. SUMMARY

[0005] The main purpose of the present application is to provide a rotor structure, an electric machine and a compressor to solve the problem of large vibration noise of the motor in the prior art.

[0006] In order to achieve the above purpose, according to the first aspect of the present application, a rotor structure is provided, which comprises a rotor core and a plurality of permanent magnets arranged on the rotor core to form a plurality of magnetic poles on the rotor core, the plurality of magnetic poles comprising a plurality of N poles and a plurality of S poles arranged alternately along the circumferential direction of the rotor core; at least one magnetic pole of the rotor core is provided with a magnetic isolation hole, and the magnetic isolation hole comprises a first hole body part and a second hole body part which are in communication with each other; wherein a plane perpendicular to the axis of the rotor core is a predetermined plane, the projection of the first hole body part on the predetermined plane is a strip and its extension direction is arranged transversely to the circumferential direction of the rotor core, and the projection of the second hole body part on the predetermined plane is a strip and is arranged transversely to the projection of the first hole body part on the predetermined plane.

[0007] Further, the extension direction of the projection of the first hole body part on the predetermined plane is the radial direction of the rotor core; or the extension direction of the projection of the first hole body part on the predetermined plane is parallel to the magnetic pole center line of the corresponding magnetic pole.

[0008] Further, the extending direction of the projection of the second hole body on the predetermined plane is perpendicular to the extending direction of the first hole body on the predetermined plane; or the extending direction of the projection of the second hole body on the predetermined plane extends along the circumferential direction of the rotor core.

[0009] Further, the second hole body is a plurality of second hole bodies, and the plurality of second hole bodies are arranged at intervals along the radial direction of the rotor core; and / or at least one second hole body is arranged at each end of the first hole body along the radial direction of the rotor core.

[0010] Further, the first hole body has a first end portion and a second end portion arranged in sequence in a direction away from the central axis of the rotor core; the second hole body is a plurality of second hole bodies, and the plurality of second hole bodies include a first branch hole, a second branch hole, and a third branch hole, the first branch hole and the third branch hole are located at the first end portion of the first hole body, and the second branch hole is located at the second end portion of the first hole body.

[0011] Further, the first end of the first branch hole communicates with the first hole body, and the second end of the first branch hole extends toward the permanent magnet on the first side of the corresponding magnetic pole; and / or the first end of the second branch hole communicates with the first hole body, and the second end of the second branch hole extends toward the permanent magnet on the first side of the corresponding magnetic pole; and / or the first end of the third branch hole communicates with the first hole body, and the second end of the third branch hole extends toward the magnetic pole center line of the corresponding magnetic pole.

[0012] Further, the extending length of the projection of the first branch hole on the predetermined plane is A, and the extending length of the projection of the second branch hole on the predetermined plane is B; wherein A≥B.

[0013] Further, the extending length of the projection of the first branch hole on the predetermined plane is A, and the extending length of the projection of the second branch hole on the predetermined plane is B; wherein 3.4≥A / B≥1.3.

[0014] Further, the center line of the extending direction of the projection of the third branch hole on the predetermined plane is on the same straight line as the center line of the extending direction of the projection of the first branch hole on the predetermined plane; and / or the extending length of the projection of the first branch hole on the predetermined plane is A, the extending length of the projection of the second branch hole on the predetermined plane is B, the extending length of the projection of the third branch hole on the predetermined plane is C, and the extending width of the projection of the first hole body on the predetermined plane is D; wherein 5.1≥(A+D+C) / (B+D)≥1.7.

[0015] Further, the extension length of the projection of the first branch hole on the predetermined plane is A, the extension length of the projection of the second branch hole on the predetermined plane is B, the extension length of the projection of the third branch hole on the predetermined plane is C, and the extension width of the projection of the first hole body on the predetermined plane is D; each magnetic pole comprises a plurality of magnetic isolation holes, and the plurality of magnetic isolation holes are arranged in pairs; the two magnetic isolation holes arranged in pairs are spaced apart to form an intermediate magnetic bridge, and the intermediate magnetic bridge has a first magnetic bridge end and a second magnetic bridge end arranged in sequence along the direction away from the axis of the rotor core; the width of the first magnetic bridge end is E, and the width of the second magnetic bridge end is F; wherein 3.8≥(A+C+D+F) / (G+E / 2)≥1.5.

[0016] Further, the width of the first branch hole in the radial direction of the rotor core is J, and the width of the second branch hole in the radial direction of the rotor core is K; wherein J≥K.

[0017] Further, the width of the first branch hole in the radial direction of the rotor core is J, and the width of the second branch hole in the radial direction of the rotor core is K; wherein 4.6≥J / K≥1.4.

[0018] Further, each magnetic pole comprises a plurality of magnetic isolation holes, and the plurality of magnetic isolation holes are arranged in pairs; the projections of the two magnetic isolation holes arranged in pairs on the plane perpendicular to the axis of the rotor core are symmetrically arranged relative to the magnetic pole center line of the corresponding magnetic pole; and / or the two magnetic isolation holes arranged in pairs are spaced apart to form an intermediate magnetic bridge, and the intermediate magnetic bridge has a first magnetic bridge end and a second magnetic bridge end arranged in sequence along the direction away from the axis of the rotor core; the width of the first magnetic bridge end along the circumferential direction of the rotor core is E, and the width of the second magnetic bridge end along the circumferential direction of the rotor core is F; wherein 0.85≥E / F≥0.3.

[0019] Further, a magnetic isolation bridge is formed between the magnetic isolation hole and the outer circumferential surface of the rotor core; along the circumferential direction of the rotor core, the width of the magnetic isolation bridge in the radial direction of the rotor core is consistent; and / or the width of the magnetic isolation bridge in the radial direction of the rotor core is P, and the width of the motor air gap of the motor formed by the rotor structure is δ; wherein 1.6≥P / δ≥0.3.

[0020] Further, the angle between the extension direction of the projection of the first branch hole on the predetermined plane and the extension direction of the projection of the first hole body on the predetermined plane is L; wherein 150°≥L≥60°.

[0021] Further, the extension direction of the projection of the first hole body on the predetermined plane is inclined relative to the magnetic pole center line of the corresponding magnetic pole.

[0022] Further, an angle between an extension direction of the projection of the first hole body on the predetermined plane and the pole center line of the corresponding magnetic pole is M, and an angle between the permanent magnet located on one side of the corresponding magnetic pole and the pole center line of the corresponding magnetic pole is N; wherein 0.5 >= M / N >= 0.2.

[0023] According to a second aspect of the present application, there is provided an electric machine comprising a stator structure and a rotor structure, the rotor structure being the above-mentioned rotor structure.

[0024] According to a third aspect of the present application, there is provided a compressor comprising an electric machine, the electric machine being the above-mentioned electric machine.

[0025] The technical scheme of the present application provides a rotor structure with a rotor core, a plurality of permanent magnets and a magnetic isolation hole, wherein the plurality of permanent magnets are uniformly distributed on the rotor core around an axis of the rotor core to form a plurality of magnetic poles including N poles and S poles; at least one magnetic pole is provided with the magnetic isolation hole, the magnetic isolation hole comprises a first hole body (i.e. a main part of the magnetic isolation hole) and a second hole body (i.e. a branch part of the magnetic isolation hole) which are in communication with each other; a plane perpendicular to the axis of the rotor core is a predetermined plane, a projection of the first hole body on the predetermined plane is a strip shape (i.e. a cross section of the first hole body perpendicular to the axis direction of the rotor core is a strip shape) and the extension direction thereof is crosswise arranged with the circumferential direction of the rotor core, and a projection of the second hole body on the predetermined plane is a strip shape and is crosswise arranged with the projection of the first hole body on the predetermined plane, which makes the width of the magnetic isolation hole have a gradient change, i.e. on a cross section of the magnetic isolation hole perpendicular to the axis direction of the rotor core, the sizes of the cross section along the radial direction and the circumferential direction of the rotor core are both gradient changes, and along the axis direction of the rotor core, the size and shape of the cross section of the magnetic isolation hole perpendicular to the axis direction of the rotor core are constant. Through the technical scheme provided by the present application, the technical effects of effectively improving the magnetic resistance distribution of each part of the magnetic circuit of the electric machine, improving the magnetic flux direction, adjusting the air gap magnetic field distribution, improving the air gap flux density waveform, reducing the tooth slot effect of the electric machine, reducing the proportion of the counter electromotive force harmonic of the electric machine, reducing the torque ripple of the electric machine, reducing the electromagnetic force density peak value of the electric machine and reducing the electromagnetic vibration noise of the electric machine are achieved, and the problem of large vibration noise of the electric machine in the prior art is solved. BRIEF DESCRIPTION OF DRAWINGS

[0026] The accompanying drawings, which form a part of the present application, are used to provide further understanding of the present application, and the illustrative embodiments of the present application and their description serve the purpose of explaining the present application. The present application is not limited by the accompanying drawings.

[0027] Figure 1 A structural schematic diagram of a rotor structure according to the first embodiment of the present application is shown;

[0028] Figure 2 A structural schematic diagram of a rotor structure according to the second embodiment of the present application is shown; Figure 1A magnetic flux path schematic diagram of the rotor structure shown;

[0029] Figure 3 A structural schematic diagram of a rotor structure according to a second embodiment of the application is shown;

[0030] Figure 4 A structural schematic diagram of a rotor structure according to a third embodiment of the application is shown;

[0031] Figure 5 A structural schematic diagram of a rotor structure according to a fourth embodiment of the application is shown;

[0032] Figure 6 A structural schematic diagram of a rotor structure according to a fifth embodiment of the application is shown;

[0033] Figure 7 A structural schematic diagram of a rotor structure according to a sixth embodiment of the application is shown;

[0034] Figure 8 A comparison diagram of torque ripple of a prior motor and a motor of the application is shown;

[0035] Figure 9 A comparison diagram of back EMF harmonic proportion of a prior motor and a motor of the application is shown;

[0036] Figure 10 A comparison diagram of electromagnetic force density peak value of a prior motor and a motor of the application is shown; and

[0037] Figure 11 A comparison diagram of total noise value of a compressor with a prior motor and a compressor with a motor of the application is shown.

[0038] Among them, the above-mentioned drawings include the following reference signs:

[0039] 1, rotor core; 2, permanent magnet; 3, magnetic pole; 31, magnetic pole center line; 4, magnetic isolation hole; 41, first hole body part; 42, second hole body part; 421, first branch hole; 422, second branch hole; 423, third branch hole; 5, intermediate magnetic bridge; 51, first magnetic bridge end; 52, second magnetic bridge end; 6, magnetic isolation bridge; 7, magnetic flux path; 71, first path area; 72, second path area; 73, third path area. DETAILED DESCRIPTION

[0040] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the drawings and in combination with the embodiments.

[0041] As Figures 1 to 7As shown, the application provides a rotor structure, comprising a rotor core 1 and a plurality of permanent magnets 2 arranged on the rotor core 1 to form a plurality of magnetic poles 3 on the rotor core 1, the plurality of magnetic poles 3 comprising a plurality of N poles and a plurality of S poles arranged alternately along the circumferential direction of the rotor core 1; at least one magnetic pole 3 of the rotor core 1 is provided with a magnetic isolation hole 4, the magnetic isolation hole 4 comprises a first hole body part 41 and a second hole body part 42 which are in communication with each other; wherein a plane perpendicular to the axis of the rotor core 1 is a predetermined plane, the projection of the first hole body part 41 on the predetermined plane is a strip shape and its extension direction is arranged transversely to the circumferential direction of the rotor core 1, and the projection of the second hole body part 42 on the predetermined plane is a strip shape and is arranged transversely to the projection of the first hole body part 41 on the predetermined plane.

[0042] The technical scheme of the application provides a rotor structure with a rotor core 1, a plurality of permanent magnets 2 and a magnetic isolation hole 4, wherein the plurality of permanent magnets 2 are uniformly distributed around the axis of the rotor core 1 to form a plurality of magnetic poles 3 on the rotor core 1, including N poles and S poles; at least one magnetic pole 3 is provided with a magnetic isolation hole 4, the magnetic isolation hole 4 comprises a first hole body part 41 (i.e. the main part of the magnetic isolation hole 4) and a second hole body part 42 (i.e. the branch part of the magnetic isolation hole 4) which are in communication with each other; a plane perpendicular to the axis of the rotor core 1 is a predetermined plane, the projection of the first hole body part 41 on the predetermined plane is a strip shape (i.e. the shape of the first hole body part 41 on the cross section perpendicular to the axis direction of the rotor core 1 is a strip shape) and its extension direction is arranged transversely to the circumferential direction of the rotor core 1, and the projection of the second hole body part 42 on the predetermined plane is a strip shape and is arranged transversely to the projection of the first hole body part 41 on the predetermined plane, which makes the width of the magnetic isolation hole 4 have a gradient change, i.e. on the cross section of the magnetic isolation hole 4 perpendicular to the axis direction of the rotor core 1, the dimensions of the cross section along the radial and circumferential directions of the rotor core 1 are both gradient changes, and along the axis direction of the rotor core 1, the size and shape of the cross section of the magnetic isolation hole 4 perpendicular to the axis direction of the rotor core 1 are unchanged. Through the technical scheme provided by the application, the technical effects of effectively improving the magnetic resistance distribution of each part of the motor magnetic circuit, improving the magnetic flux direction, adjusting the air gap magnetic field distribution, improving the air gap flux density waveform, reducing the tooth slot effect of the motor, reducing the proportion of motor back electromotive force harmonics, reducing the torque ripple of the motor, reducing the electromagnetic force density peak value of the motor and reducing the electromagnetic vibration noise of the motor are achieved, and the problem of large vibration noise of the motor in the prior art is solved.

[0043] Specifically, the rotor core 1 is made of a material with strong magnetic conductivity, which makes the magnetic resistance of the rotor core 1 small. Alternatively, the rotor core 1 is made of a plurality of silicon steel sheets stacked together, which makes the magnetic lines easy to pass through. Since the air or other non-magnetic material in the magnetic isolation hole 4 has poor magnetic conductivity and large magnetic resistance, the magnetic lines are not easy to pass through. Therefore, by providing the magnetic isolation hole 4, the magnetic resistance distribution of the magnetic circuit of the motor rotor structure can be changed, the magnetic line direction in the rotor structure can be changed, the air gap magnetic flux waveform can be improved, and thus the proportion of back electromotive force harmonics, motor torque ripple, electromagnetic force amplitude, and motor electromagnetic vibration noise can be reduced.

[0044] As shown in Figure 2 , a schematic diagram of the magnetic flux direction of the rotor structure of the embodiment provided by the present application is shown, the line with an arrow is the identification of the magnetic line, the solid line with an arrow indicates that more magnetic lines pass through at this position, and the dashed line with an arrow indicates that few magnetic lines pass through at this position. As can be clearly seen from Figure 2 , at the position where the magnetic isolation hole 4 is located, fewer magnetic lines pass through, and the magnetic isolation hole 4 provided by the present application effectively improves the magnetic line distribution of the rotor structure.

[0045] In the embodiment shown in Figures 1 to 7 , the extension direction of the projection of the first hole body part 41 on the predetermined plane is the radial direction of the rotor core 1; or the extension direction of the projection of the first hole body part 41 on the predetermined plane is parallel to the magnetic pole center line 31 of the corresponding magnetic pole 3.

[0046] In the embodiment shown in Figures 1 to 7 , the extension direction of the projection of the second hole body part 42 on the predetermined plane is perpendicular to the extension direction of the first hole body part 41 on the predetermined plane; or the extension direction of the projection of the second hole body part 42 on the predetermined plane extends along the circumferential direction of the rotor core 1.

[0047] In the embodiment shown in Figures 1 to 7 , the second hole body part 42 is a plurality of second hole body parts 42, and the plurality of second hole body parts 42 are arranged at intervals along the radial direction of the rotor core 1; and / or at least one second hole body part 42 is arranged at each end of the first hole body part 41 along the radial direction of the rotor core 1.

[0048] The rotor structure provided by the application adopts the "J" shaped structure of the magnetic isolation hole 4. The magnetic isolation hole 4 has a first hole body part 41 extending in the radial direction of the rotor core 1, that is, the main part of the magnetic isolation hole 4, and a second hole body part 42 extending in the circumferential direction of the rotor, that is, the branch part extending from the main part of the magnetic isolation hole 4. The first hole body part 41 has a first end part and a second end part in the circumferential direction of the rotor core 1 and a first head part and a second head part in the radial direction of the rotor core 1. The second hole body part 42 includes a first branch hole 421, a second branch hole 422 and a third branch hole 423. In the magnetic isolation hole 4, the first branch hole 421, the second branch hole 422 and the third branch hole 423 are respectively arranged at the first end part and the second end part of the first hole body part 41, and the first branch hole 421, the second branch hole 422 and the third branch hole 423 are respectively arranged at the first head part and the second head part of the first hole body part 41, so that the shape of the magnetic isolation hole 4 is a "J" shaped structure with a width narrowing in the middle and widening at both ends in the radial direction of the rotor core 1, and the width of the magnetic isolation hole 4 in the radial direction of the rotor core 1 has a gradient change. In this way, the magnetic flux distribution at the magnetic conduction area between the first branch hole 421 and the permanent magnet 2 and at the intermediate magnetic bridge 5 can be improved, the magnetic conductance of the rotor structure at each part of the magnetic circuit during the operation of the motor is more uniform, the air gap magnetic flux waveform is improved, the torque ripple of the motor is reduced, the proportion of the motor's counter electromotive force harmonic is reduced, the peak value of the motor's electromagnetic force density and the electromagnetic vibration noise are reduced.

[0049] Specifically, the first hole body part 41 has a first end part and a second end part arranged in sequence in a direction away from the central axis of the rotor core 1; the second hole body part 42 is a plurality of, and the plurality of second hole body parts 42 include a first branch hole 421, a second branch hole 422 and a third branch hole 423, the first branch hole 421 and the third branch hole 423 are located at the first end part of the first hole body part 41, and the second branch hole 422 is located at the second end part of the first hole body part 41.

[0050] The first end of the first branch hole 421 communicates with the first hole body part 41, and the second end of the first branch hole 421 extends towards the permanent magnet 2 on the first side of the corresponding magnetic pole 3; and / or the first end of the second branch hole 422 communicates with the first hole body part 41, and the second end of the second branch hole 422 extends towards the permanent magnet 2 on the first side of the corresponding magnetic pole 3; and / or the first end of the third branch hole 423 communicates with the first hole body part 41, and the second end of the third branch hole 423 extends towards the magnetic pole center line 31 of the corresponding magnetic pole 3.

[0051] Optionally, as Figures 1 to 5In the embodiment shown, the first branch hole 421 extends from the first end of the first hole body 41 near the central axis of the rotor core 1 toward the permanent magnet 2, the second branch hole 422 extends from the first end of the first hole body 41 away from the central axis of the rotor core 1 toward the permanent magnet 2, and the third branch hole 423 extends from the second end of the first hole body 41 near the central axis of the rotor core 1 toward the magnetic pole center line 31. The third branch hole 423 and the first branch hole 421 are on the same straight line.

[0052] like Figures 6 to 7 In the illustrated embodiment, the first branch hole 421 extends from the first end of the first hole body 41 near the central axis of the rotor core 1 toward the permanent magnet 2; the second branch hole 422 extends from the first end of the first hole body 41 away from the central axis of the rotor core 1 toward the permanent magnet 2; and the third branch hole 423 extends from the second end of the first hole body 41 away from the central axis of the rotor core 1 toward the magnetic pole centerline 31. The third branch hole 423 and the second branch hole 422 are on the same straight line. This makes the width E of the intermediate magnetic bridge 5 near the central axis of the rotor core 1 larger than the width F of the side away from the central axis of the rotor core 1, changing the magnetic reluctance distribution near the outer circumference of the rotor core 1, improving the air gap magnetic flux density waveform, and reducing the proportion of back EMF harmonics, the peak electromagnetic force density, and the vibration noise of the motor.

[0053] exist Figure 1 In the embodiment shown, the extension length of the projection of the first branch hole 421 onto the predetermined plane is A, and the extension length of the projection of the second branch hole 422 onto the predetermined plane is B; wherein, A≥B.

[0054] exist Figure 1 In the embodiment shown, the extension length of the projection of the first branch hole 421 onto the predetermined plane is A, and the extension length of the projection of the second branch hole 422 onto the predetermined plane is B; wherein, 3.4≥A / B≥1.3.

[0055] The projections of the first branch hole 421 and the second branch hole 422 onto the predetermined plane are strip-shaped. The extension length A of the projection of the first branch hole 421 onto the predetermined plane is its width in the circumferential direction of the rotor core 1. The extension length B of the projection of the second branch hole 422 onto the predetermined plane is its width in the circumferential direction of the rotor core 1.

[0056] By setting the widths A and B of the first branch hole 421 and the second branch hole 422 in the circumferential direction of the rotor core 1, this application can make the first branch hole 421 closer to the side of the permanent magnet near the axis of the rotor core 1, effectively improving the magnetic flux direction.

[0057] If the width B of the second branch hole 422 in the circumferential direction of the rotor core 1 is too large, the magnetic resistance at the air gap will increase, and the output torque of the motor will decrease. Therefore, the width of the second branch hole 422 in the circumferential direction of the rotor core 1 is greater than the width of the first branch hole 421 in the circumferential direction of the rotor core 1, that is, A≥B. When the value of A / B is set to be in the range of 1.3 to 3.4, the magnetic field distribution at the air gap can be effectively improved, and the peak value of the electromagnetic force density of the motor and the electromagnetic vibration noise of the motor can be reduced.

[0058] Preferably, in Figure 5 In the embodiment shown, the width of the first branch hole 421 and the second branch hole 422 in the circumferential direction of the rotor core 1 is equal, that is, A=B. The first branch hole 421 and the second branch hole 422 are filled with non-magnetic substances, and the magnetic resistance is relatively large. The first branch hole 421 is closer to the permanent magnet than the second branch hole 422, and the second branch hole 422 is on the same straight line as the third branch hole 423. Therefore, the magnetic resistance of the rotor core 1 near the outer circumferential surface is larger, and the width A of the first branch hole 421 in the circumferential direction of the rotor core 1 should not be too large. If it is too large, the torque of the motor will decrease significantly, and the efficiency of the motor will also decrease.

[0059] In Figure 1 In the embodiment shown, the center line of the extension direction of the projection of the third branch hole 423 on the predetermined plane is on the same straight line as the center line of the extension direction of the projection of the first branch hole 421 on the predetermined plane; and / or the extension length of the projection of the first branch hole 421 on the predetermined plane is A, the extension length of the projection of the second branch hole 422 on the predetermined plane is B, the extension length of the projection of the third branch hole 423 on the predetermined plane is C, and the extension width of the projection of the first hole body portion 41 on the predetermined plane is D; wherein 5.1≥(A+D+C) / (B+D)≥1.7.

[0060] The projection of the first hole body portion 41 and the third branch hole 423 on the predetermined plane is a strip shape. The extension width D of the projection of the first hole body portion 41 on the predetermined plane is the width of the first hole body portion 41 in the circumferential direction of the rotor core 1. The extension direction of the projection of the first hole body portion 41 on the predetermined plane is the radial direction of the rotor core 1. The extension length C of the projection of the third branch hole 423 on the predetermined plane is the width of the third branch hole 423 in the circumferential direction of the rotor core 1. The extension direction of the projection of the third branch hole 423 on the predetermined plane is the circumferential direction of the rotor core 1.

[0061] In Figure 1In the illustrated embodiment, the third branch hole 423 is on the same line as the extension direction of the first branch hole 421, so that the width of the side of the magnetic isolation hole 4 close to the central axis of the rotor core 1 in the circumferential direction of the rotor core 1 is greater than the width of the side away from the central axis of the rotor core 1 in the circumferential direction of the rotor core 1.

[0062] The first branch hole 421 and the third branch hole 423 are filled with air or other non-magnetic substances, and the magnetic resistance is large. The first branch hole 421 and the third branch hole 423 extend in the circumferential direction of the rotor core 1, so that the magnetic flux of the permanent magnet 2 close to the central axis of the rotor core 1 is concentrated in the regions of the two ends of the magnetic pole 3 and the intermediate magnetic bridge 5. When the value of (A+D+C) / (B+D) is set to be in the range of 1.7 to 5.1, the permeance distribution inside and outside the rotor structure is more uniform, the magnetic field distribution at the air gap is improved, the harmonic and harmonic loss are reduced, the working efficiency of the motor is improved, and the peak value of the electromagnetic force density and the electromagnetic vibration noise of the motor are reduced.

[0063] In Figure 1 In the illustrated embodiment, the extension length of the projection of the first branch hole 421 on the predetermined plane is A, the extension length of the projection of the second branch hole 422 on the predetermined plane is B, the extension length of the projection of the third branch hole 423 on the predetermined plane is C, and the extension width of the projection of the first hole body portion 41 on the predetermined plane is D. Each magnetic pole 3 includes a plurality of magnetic isolation holes 4, and the plurality of magnetic isolation holes 4 are arranged in pairs. The two magnetic isolation holes 4 in each pair are spaced apart to form an intermediate magnetic bridge 5, and the intermediate magnetic bridge 5 has a first magnetic bridge end 51 and a second magnetic bridge end 52 arranged in sequence along the direction away from the axis of the rotor core 1. The width of the first magnetic bridge end 51 is E, and the width of the second magnetic bridge end 52 is F. Wherein, 3.8≥(A+C+D+F) / (G+E / 2)≥1.5.

[0064] Specifically, the intermediate magnetic bridge 5 is a rectangular strip, and the width direction of the first magnetic bridge end 51 and the width direction of the second magnetic bridge end 52 of the intermediate magnetic bridge 5 are directions perpendicular to the length direction of the intermediate magnetic bridge 5. Preferably, the width direction of the first magnetic bridge end 51 and the width direction of the second magnetic bridge end 52 of the intermediate magnetic bridge 5 are the circumferential direction of the rotor core 1.

[0065] In this embodiment, a distance is left between the first branch hole 421 and the permanent magnet 2. The minimum distance between the first branch hole 421 and the permanent magnet 2 is G, and the thickness of the permanent magnet 2 is H. The first branch hole 421 of the two magnetic isolation holes 4 at the same magnetic pole 3 forms a first path region 71 and a second path region 72 of the magnetic conductive path 7 with the permanent magnet 2 it is close to. The two magnetic isolation holes 4 form a third path region 73 of the magnetic conductive path 7. The magnetic resistance at the magnetic conductive path 7 is small. The first branch hole 421 and the third branch hole 423 extend along the circumference of the rotor core 1. The first branch hole 421 and the third branch hole 423 are filled with non-magnetic materials such as air, and their magnetic resistance is large. This makes the magnetic flux of the permanent magnet 2 on the side close to the central axis of the rotor core 1 concentrated in the area of ​​the two ends of the magnetic pole 3 and the middle magnetic bridge 5.

[0066] When the value of (A+C+D+F) / (G+E / 2) is set within the range of 1.5 to 3.8, the magnetic permeability distribution in the rotor structure becomes more uniform, and the air gap magnetic flux density waveform is improved, thereby reducing the motor's torque ripple and electromagnetic vibration noise. For example... Figure 10 As shown, this setting reduces the peak electromagnetic force density of the 6th and 18th harmonics of the 6-pole motor, thereby reducing the electromagnetic vibration noise of the motor.

[0067] like Figure 3 In the embodiment shown, the width of the first branch hole 421 along the radial direction of the rotor core 1 is J, and the width of the second branch hole 422 along the radial direction of the rotor core 1 is K; wherein, J≥K.

[0068] like Figure 3 In the embodiment shown, the width of the first branch hole 421 along the radial direction of the rotor core 1 is J, and the width of the second branch hole 422 along the radial direction of the rotor core 1 is K; wherein, 4.6≥J / K≥1.4.

[0069] The presence of the first branch hole 421 can change the magnetic flux direction on the side of the permanent magnet 2 near the central axis of the rotor core 1, thereby adjusting the magnitude of the magnetic flux in each region. The presence of the second branch hole 422 can change the magnetic flux direction near the outer circumference of the rotor core 1, thereby adjusting the air gap magnetic field distribution. The width of the first branch hole 421 in the radial direction of the rotor core 1 is not less than the width of the second branch hole 422 in the radial direction of the rotor core 1, i.e., J≥K. When the value of J / K is set in the range of 1.4 to 4.6, the magnitude of the magnetic flux and the air gap magnetic field distribution in each region can be better adjusted, thereby improving the air gap magnetic flux density waveform of the motor, reducing the proportion of back EMF harmonics, the peak value of electromagnetic force density, and the vibration noise of the motor.

[0070] exist Figure 1In the shown embodiment, each magnetic pole 3 comprises a plurality of magnetic isolation holes 4, the plurality of magnetic isolation holes 4 are arranged in pairs; the projections of the two magnetic isolation holes 4 in a plane perpendicular to the axis of the rotor core 1 are symmetrically arranged relative to the magnetic pole center line 31 of the corresponding magnetic pole 3; and / or the two magnetic isolation holes 4 are arranged at intervals to form an intermediate magnetic bridge 5, the intermediate magnetic bridge 5 has a first magnetic bridge end 51 and a second magnetic bridge end 52 arranged in sequence along the direction away from the axis of the rotor core 1; the width of the first magnetic bridge end 51 along the circumferential direction of the rotor core 1 is E, and the width of the second magnetic bridge end 52 along the circumferential direction of the rotor core 1 is F; wherein 0.85≥E / F≥0.3.

[0071] Each magnetic pole 3 of the rotor structure has three magnetic flux paths 7, the part left between the two magnetic isolation holes 4 can pass the magnetic force lines to form the third path area 73 of the magnetic flux path 7, and the part left between each first branch hole 421 and the permanent magnet 2 close to it can pass the magnetic force lines to form the first path area 71 and the second path area 72 of the magnetic flux path 7.

[0072] Each magnetic pole 3 has at least two magnetic isolation holes 4 with "J" shape structure, the two magnetic isolation holes 4 are symmetrical about the magnetic pole center line 31, the magnetic isolation holes are filled with air or other non-magnetic substances, the magnetic resistance is large, and only a small part of the magnetic force lines can pass through. The distance between the two magnetic isolation holes 4 is also called the intermediate magnetic bridge 5, the first magnetic bridge end 51 of the intermediate magnetic bridge 5 is located on the side close to the central axis of the rotor core 1, and the second magnetic bridge end 52 is located on the side away from the central axis of the rotor core 1, the width of the first magnetic bridge end 51 along the circumferential direction of the rotor core 1 is smaller than the width of the second magnetic bridge end 52 along the circumferential direction of the rotor core 1, and the value of E / F is set in the range of 0.3 to 0.85, which can better improve the magnetic flux of each magnetic flux path 7, and then improve the air gap magnetic density waveform, reduce the torque ripple of the motor, reduce the electromagnetic force density peak value of the motor, and reduce the electromagnetic vibration noise of the motor.

[0073] As shown in the embodiment, Figure 3 In the shown embodiment, the magnetic isolation hole 4 and the outer circumferential surface of the rotor core 1 form a magnetic isolation bridge 6; along the circumferential direction of the rotor core 1, the width of the magnetic isolation bridge 6 along the radial direction of the rotor core 1 is consistent; and / or the width of the magnetic isolation bridge 6 along the radial direction of the rotor core 1 is P, and the width of the motor air gap of the motor formed by the rotor structure is δ; wherein 1.6≥P / δ≥0.3.

[0074] Wherein, the width δ of the motor air gap of the motor formed by the rotor structure is the gap between the rotor and the stator of the motor, and the air gap magnetic density refers to the magnetic induction intensity of the magnetic field existing in the air gap.

[0075] A magnetic isolation bridge 6 is located between the main body of the magnetic isolation hole 4 (i.e., the first hole body 41) and the outer peripheral surface of the rotor core 1. The magnetic isolation bridge 6 allows a portion of the magnetic lines of force to be transmitted to the air gap. Along the radial direction of the rotor core 1, the width of the magnetic isolation bridge 6 is uniform. When the value of P / δ is set in the range of 0.3 to 1.6, the magnetic flux transmitted at the magnetic isolation bridge 6 is optimal, the air gap magnetic flux density waveform is optimally improved, the peak value of the electromagnetic force density of the motor is minimized, and the vibration and noise of the motor are also minimized.

[0076] like Figure 4 In the embodiment shown, the angle between the extension direction of the projection of the first branch hole 421 onto the predetermined plane and the extension direction of the projection of the first hole body 41 onto the predetermined plane is L; wherein, 150°≥L≥60°.

[0077] There is a certain angle L between the first branch hole 421 and the main body (i.e., the first hole body 41) of the magnetic isolation hole 4. When the value of L is set in the range of 60° to 150°, the first branch hole 421 is closer to the side of the permanent magnet 2 near the central axis of the rotor core 1. This changes the magnetic flux in the area of ​​the permanent magnet 2 near the central axis of the rotor core 1, the magnetic flux in the area of ​​the intermediate magnetic bridge 5 near the central axis of the rotor core 1, and the magnetic flux at both ends of the magnetic pole 3 near the outer peripheral surface of the rotor core 1. This improves the magnetic flux density distribution in the area of ​​each magnetic conduction path 7, improves the magnetic field distribution and air gap magnetic flux density waveform, and reduces the proportion of back EMF harmonics, the peak value of electromagnetic force density, and the vibration noise of the motor.

[0078] exist Figure 7 In the embodiment shown, the projection of the first hole portion 41 onto a predetermined plane extends in an inclined direction relative to the magnetic pole centerline 31 of the corresponding magnetic pole 3.

[0079] Preferably, the angle between the extension direction of the projection of the first hole portion 41 on the predetermined plane and the magnetic pole center line 31 of the corresponding magnetic pole 3 is M, and the angle between the permanent magnet 2 located on one side of the corresponding magnetic pole 3 and the magnetic pole center line 31 of the magnetic pole 3 is N; wherein, 0.5≥M / N≥0.2.

[0080] Specifically, the "J"-shaped magnetic isolation hole 4 has an extended portion in both the radial and circumferential directions of the rotor core 1, and is inclined relative to the magnetic pole centerline 31. The extension direction of the projection of the first hole portion 41 onto the predetermined plane is the radial direction of the rotor core 1. Setting the value of M / N in the range of 0.2 to 0.5 can make the magnetic permeability distribution in the radial and circumferential directions of the rotor core 1 more uniform, thereby improving the magnetic field distribution and magnetic flux density waveform of the air gap of the motor, reducing the proportion of back EMF harmonics, the peak value of electromagnetic force density, and the vibration noise of the motor.

[0081] According to a second aspect of the present application, there is provided an electric machine comprising a stator structure and a rotor structure, the rotor structure being as described above. In this way, the vibration noise of the electric machine can be reduced.

[0082] According to a third aspect of the present application, there is provided a compressor comprising an electric machine, the electric machine being as described above. In this way, the vibration noise of the compressor can be reduced.

[0083] As shown in Fig. 6, it can be clearly seen that the torque ripple range of the electric machine of the present application is much smaller than that of the existing electric machine. Figure 8 Figure 8 As shown in Fig. 7, it can be clearly seen that the back EMF harmonic ratio of the electric machine of the present application is much smaller than that of the existing electric machine.

[0084] As shown in Fig. 8, it can be clearly seen that the electromagnetic force density peak values of the electric machine of the present application at 6 times frequency, 12 times frequency, 18 times frequency, 24 times frequency, 30 times frequency and 36 times frequency are much smaller than those of the existing electric machine. Figure 9 Figure 9 As shown in Fig. 9, it can be clearly seen that the total noise value of the compressor with the electric machine of the present application is much smaller than that of the compressor with the existing electric machine.

[0085] As shown in Fig. 10, it can be clearly seen that the total noise value of the compressor with the electric machine of the present application is much smaller than that of the compressor with the existing electric machine. Figure 10 Figure 10 As shown in Fig. 11, it can be clearly seen that the total noise value of the compressor with the electric machine of the present application is much smaller than that of the compressor with the existing electric machine.

[0086] As shown in Fig. 12, it can be clearly seen that the total noise value of the compressor with the electric machine of the present application is much smaller than that of the compressor with the existing electric machine. Figure 11 Figure 11 As shown in Fig. 13, it can be clearly seen that the total noise value of the compressor with the electric machine of the present application is much smaller than that of the compressor with the existing electric machine.

[0087] The rotor structure comprises a rotor core 1 and permanent magnets 2. The permanent magnets 2 are arranged in permanent magnet grooves in the rotor core 1, and the permanent magnets 2 on the rotor form N poles and S poles which are alternately distributed. A magnetic pole 3 of the rotor core 1 is provided with a magnetic isolation hole 4. The magnetic isolation hole 4 has a first hole body part 41 extending along a radial direction of the rotor core 1, i.e. a main stem part of the magnetic isolation hole 4, and a second hole body part 42 extending along a circumferential direction of the rotor core 1, i.e. a first branch hole 421, a second branch hole 422 and a third branch hole 423 extending from the main stem part of the magnetic isolation hole 4. In this way, the width of the magnetic isolation hole 4 along the circumferential direction and the radial direction of the rotor core 1 has a gradient change, and the width of the magnetic isolation hole 4 is narrow in the middle and wide at both ends along the extension direction of the magnetic isolation hole 4, i.e. a "J" shaped structure. ​​​​

[0088] Permanent magnet motor relies on permanent magnet 2 to generate main magnetic field, the air gap flux density of permanent magnet motor is high, the working efficiency is high, the volume is small, the power density is high, the structure is simple, the reliability is high, and it is widely used in various industries. But in the permanent magnet synchronous motor, the magnetic energy product of the permanent magnet 2 made of fixed grade material is constant, the adjustment of the air gap magnetic field of the motor is difficult, at the same time, the tooth structure of the motor makes the air gap flux density, the harmonic content of back electromotive force is large, the electromagnetic force density peak of the motor is large, so as to cause the torque ripple and vibration noise of the motor is large.

[0089] The present application changes the magnetic resistance distribution of the motor by opening the "J" shaped structure of the magnetic isolation hole 4 on the rotor core 1, realizes the reduction of the cogging effect of the motor, reduces the torque ripple of the motor, improves the air gap flux density waveform, reduces the harmonic ratio of the motor, reduces the electromagnetic force density peak of the motor, and reduces the electromagnetic vibration noise of the motor. The technical effect of solving the problem of high air gap flux density, high back electromotive force waveform distortion rate, large motor torque ripple, large motor electromagnetic force and large motor vibration and noise of the permanent magnet synchronous motor.

[0090] The application of the technical scheme of the present application provides a rotor structure with rotor core 1, a plurality of permanent magnets 2 and magnetic isolation hole 4, wherein the plurality of permanent magnets 2 are uniformly distributed on the rotor core 1 to form a plurality of magnetic poles 3 around the axis of the rotor core 1, including N pole and S pole; at least one magnetic pole 3 is provided with a magnetic isolation hole 4, the magnetic isolation hole 4 includes a first hole body part 41 (i.e. the main part of the magnetic isolation hole 4) and a second hole body part 42 (i.e. the branch part of the magnetic isolation hole 4) which are in communication with each other; the plane perpendicular to the axis of the rotor core 1 is the predetermined plane, the projection of the first hole body part 41 on the predetermined plane is strip-shaped (i.e. the cross section of the first hole body part 41 perpendicular to the axis direction of the rotor core 1 is strip-shaped) and its extension direction is crosswise arranged with the circumferential direction of the rotor core 1, the projection of the second hole body part 42 on the predetermined plane is strip-shaped and crosswise arranged with the projection of the first hole body part 41 on the predetermined plane, which makes the width of the magnetic isolation hole 4 have a gradient change, i.e. on the cross section of the magnetic isolation hole 4 perpendicular to the axis direction of the rotor core 1, the size of the cross section along the radial and circumferential directions of the rotor core 1 is gradiently changed, and along the axis direction of the rotor core 1, the size and shape of the cross section of the magnetic isolation hole 4 perpendicular to the axis direction of the rotor core 1 are unchanged. Through the technical scheme provided by the present application, the magnetic resistance distribution of the motor magnetic circuit is effectively improved, the magnetic flux direction is improved, the air gap magnetic field distribution is adjusted, the air gap flux density waveform is improved, the cogging effect of the motor is reduced, the harmonic ratio of the motor is reduced, the torque ripple of the motor is reduced, the electromagnetic force density peak of the motor is reduced, and the electromagnetic vibration noise of the motor is reduced. The problem of large vibration noise of the motor in the prior art is solved.

[0091] The above merely provides the preferred embodiments of the present application, and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the principles and technical scope of the present application shall fall into the scope of the present application.

Claims

1. A rotor structure comprising a rotor core (1) and a plurality of permanent magnets (2) arranged on the rotor core (1) to form a plurality of magnetic poles (3) on the rotor core (1), the plurality of magnetic poles (3) comprising a plurality of N poles and a plurality of S poles arranged alternately along a circumferential direction of the rotor core (1); characterized in that, at least one of the magnetic poles (3) of the rotor core (1) is provided with a magnetic isolation hole (4), the magnetic isolation hole (4) comprising a first hole body portion (41) and a second hole body portion (42) in communication with each other; wherein a plane perpendicular to an axis of the rotor core (1) is a predetermined plane, a projection of the first hole body portion (41) on the predetermined plane is a strip-shaped and is arranged with an extending direction intersecting a circumferential direction of the rotor core (1), and a projection of the second hole body portion (42) on the predetermined plane is a strip-shaped and is arranged intersecting the projection of the first hole body portion (41) on the predetermined plane; each of the magnetic poles (3) comprises a plurality of the magnetic isolation holes (4), and the plurality of the magnetic isolation holes (4) are arranged in pairs; projections of the two magnetic isolation holes (4) in a pair on a plane perpendicular to the axis of the rotor core (1) are symmetrically arranged relative to a magnetic pole center line (31) of the corresponding magnetic pole (3); the two magnetic isolation holes (4) in a pair are arranged with an interval to form an intermediate magnetic bridge (5), the intermediate magnetic bridge (5) has a first magnetic bridge end (51) and a second magnetic bridge end (52) arranged in sequence along a direction away from the axis of the rotor core (1); a width of the first magnetic bridge end (51) along the circumferential direction of the rotor core (1) is E, and a width of the second magnetic bridge end (52) along the circumferential direction of the rotor core (1) is F; wherein 0.85≥E / F≥0.

3.

2. The rotor structure of claim 1, wherein the extending direction of the projection of the first hole body portion (41) on the predetermined plane is a radial direction of the rotor core (1); or the extending direction of the projection of the first hole body portion (41) on the predetermined plane is parallel to the magnetic pole center line (31) of the corresponding magnetic pole (3).

3. The rotor structure according to claim 1, characterized in that, the extending direction of the projection of the second hole body portion (42) on the predetermined plane is perpendicular to the extending direction of the first hole body portion (41) on the predetermined plane; or the extending direction of the projection of the second hole body portion (42) on the predetermined plane extends along the circumferential direction of the rotor core (1). the second hole body portion (42) is a plurality of, 4. The rotor structure of claim 1, wherein the plurality of second hole body portions (42) are arranged with an interval along a radial direction of the rotor core (1); and / or at least one of the second hole body portions (42) is arranged at each of two ends of the first hole body portion (41) along the radial direction of the rotor core (1). ​ 5. The rotor structure of claim 1, wherein The first hole body part (41) has a first end part and a second end part arranged in sequence in a direction away from a central axis of the rotor core (1); the second hole body part (42) is multiple, and the multiple second hole body parts (42) include a first branch hole (421), a second branch hole (422), and a third branch hole (423), the first branch hole (421) and the third branch hole (423) are located at the first end part of the first hole body part (41), and the second branch hole (422) is located at the second end part of the first hole body part (41).

6. The rotor structure of claim 5, wherein, a first end of the first branch hole (421) communicates with the first hole body part (41), and a second end of the first branch hole (421) extends towards the permanent magnet (2) on the first side of the corresponding magnetic pole (3); and / or a first end of the second branch hole (422) communicates with the first hole body part (41), and a second end of the second branch hole (422) extends towards the permanent magnet (2) on the first side of the corresponding magnetic pole (3); and / or a first end of the third branch hole (423) communicates with the first hole body part (41), and a second end of the third branch hole (423) extends towards the pole center line (31) of the corresponding magnetic pole (3).

7. The rotor structure of claim 5, wherein The extension length of the projection of the first branch hole (421) on the predetermined plane is A, and the extension length of the projection of the second branch hole (422) on the predetermined plane is B; wherein A≥B.

8. The rotor structure of claim 5, wherein The extension length of the projection of the first branch hole (421) on the predetermined plane is A, and the extension length of the projection of the second branch hole (422) on the predetermined plane is B; wherein 3.4≥A / B≥1.

3.

9. The rotor structure of claim 5, wherein, the center line of the extension direction of the projection of the third branch hole (423) on the predetermined plane is on the same straight line as the center line of the extension direction of the projection of the first branch hole (421) on the predetermined plane; and / or the extension length of the projection of the first branch hole (421) on the predetermined plane is A, the extension length of the projection of the second branch hole (422) on the predetermined plane is B, the extension length of the projection of the third branch hole (423) on the predetermined plane is C, and the extension width of the projection of the first hole body part (41) on the predetermined plane is D; wherein 5.1≥(A+D+C) / (B+D)≥1.

7.

10. The rotor structure of claim 5, wherein An extension length of a projection of the first branch hole (421) on the predetermined plane is A, an extension length of a projection of the second branch hole (422) on the predetermined plane is B, an extension length of a projection of the third branch hole (423) on the predetermined plane is C, and an extension width of a projection of the first hole body (41) on the predetermined plane is D; each of the magnetic poles (3) comprises a plurality of the magnetic isolation holes (4), and the plurality of the magnetic isolation holes (4) are arranged in pairs; two magnetic isolation holes (4) in each pair are arranged with a spacing to form an intermediate magnetic bridge (5), and the intermediate magnetic bridge (5) has a first magnetic bridge end (51) and a second magnetic bridge end (52) arranged in sequence along an axis direction away from the rotor core (1); a width of the first magnetic bridge end (51) is E, and a width of the second magnetic bridge end (52) is F; a minimum distance between the first branch hole (421) and the permanent magnet (2) is G; and 3.8≥(A+C+D+F) / (G+E / 2)≥1.

5.

11. The rotor structure of claim 5, wherein A width of the first branch hole (421) along a radial direction of the rotor core (1) is J, and a width of the second branch hole (422) along the radial direction of the rotor core (1) is K; and J≥K.

12. The rotor structure of claim 5, wherein A width of the first branch hole (421) along a radial direction of the rotor core (1) is J, and a width of the second branch hole (422) along the radial direction of the rotor core (1) is K; and 4.6≥J / K≥1.

4.

13. The rotor structure of claim 1, wherein The magnetic isolation hole (4) and an outer circumferential surface of the rotor core (1) form a magnetic isolation bridge (6); Along a circumferential direction of the rotor core (1), the magnetic isolation bridge (6) has a consistent width in a radial direction of the rotor core (1); and / or A width of the magnetic isolation bridge (6) in the radial direction of the rotor core (1) is P, and a width of a motor air gap of a motor formed by the rotor structure is δ; and 1.6≥P / δ≥0.

3.

14. The rotor structure of claim 1, wherein An included angle between an extension direction of a projection of the first branch hole (421) of the second hole body (42) on the predetermined plane and an extension direction of a projection of the first hole body (41) on the predetermined plane is L; and 150°≥L≥60°.

15. The rotor structure of claim 1, wherein An extension direction of a projection of the first hole body (41) on the predetermined plane is arranged obliquely relative to a magnetic pole center line (31) of the corresponding magnetic pole (3).

16. The rotor structure of claim 1, wherein An included angle between an extension direction of a projection of the first hole body (41) on the predetermined plane and a magnetic pole center line (31) of the corresponding magnetic pole (3) is M, and an included angle between the permanent magnet (2) on one side of the corresponding magnetic pole (3) and the magnetic pole center line (31) of the magnetic pole (3) is N; and 0.5≥M / N≥0.

2.

17. An electric machine comprising a stator structure and a rotor structure, characterized in that The rotor structure is the rotor structure according to any one of claims 1 to 16.

18. A compressor comprising a motor, characterized by The motor is the motor according to claim 17.

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