Rotor core, rotor, motor and compressor

Abstract

The invention provides a rotor core, a rotor, a motor and a compressor, the rotor core is provided with more than two magnetic steel groove groups which are uniformly arranged at intervals along the circumferential direction, each magnetic steel groove group is provided with two magnetic steel grooves which are distributed in a V shape, each magnetic steel groove is provided with a first groove wall and a second groove wall which are opposite to each other, the first groove wall is used for being opposite to an excitation surface of magnetic steel in the magnetic steel groove; in a cross section perpendicular to the axis of the rotor core, the second groove walls in the magnetic steel grooves are linear, the first groove walls are arc-shaped, and the concave surfaces of the arcs face the second groove walls. Wherein the first groove wall is matched with the second groove wall, so that the magnetic gathering capability of the magnetic steel in the magnetic steel groove can be improved, a better magnetic gathering effect is achieved, larger magnetic flux is provided, and magnetic leakage of the motor is reduced, and therefore, the counter electromotive force of the motor can be improved, the output torque of unit current is improved, the copper consumption of the motor is reduced, and the power density and the efficiency of the motor are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of motors, and particularly relates to a rotor core, a rotor, a motor, and a compressor. Background Art

[0002] Due to the advantages of simple structure, high efficiency, large output torque, adjustable speed, small volume and light weight, permanent magnet synchronous motors have been widely used in many fields and achieved good results, especially in the field of refrigeration compressors. With the release of the new national standard, there are higher requirements for improving the energy efficiency of compressors. In view of the improvement of the energy efficiency level, existing refrigeration compressors mostly use permanent magnet synchronous motors as power components to improve the energy efficiency of compressors.

[0003] Currently, the use of concentrated winding permanent magnet synchronous motors on piston compressors has been relatively common. As Figure 1 shown, the motor rotor structure of the piston compressor has a sunken hole 1 design. Specifically, in order to avoid the cylinder block of the piston compressor, in addition to the shaft hole 4 that is interference-fitted with the crankshaft (generally, the diameter of the shaft hole 4 is 14 mm to 19 mm), a sunken hole 5 with a diameter of about 25 mm needs to be provided on the side of the rotor close to the cylinder block to avoid the cylinder block. For the V-shaped rotor design, it means that the available area for designing the magnet slots on the rotor punching sheet will be greatly reduced, and a large amount of available area of the rotor punching sheet will be wasted on the shaft hole side, affecting the magnet distribution and thus the motor efficiency. Summary of the Invention

[0004] Therefore, the present invention provides a rotor core, a rotor, a motor, and a compressor. The main technical problem to be solved is: how to improve the motor efficiency.

[0005] To solve the above problems, the present invention provides a rotor core. The rotor core has two or more magnet slot groups arranged at equal intervals circumferentially. Each magnet slot group has two magnet slots distributed in a V shape. Each magnet slot has opposite first and second slot walls, and the first slot wall is used to face the excitation surface of the magnet in the magnet slot.

[0006] Wherein, in a cross-section perpendicular to the axis of the rotor core, the second slot wall in the magnet slot is linear, and the first slot wall is arc-shaped, and the concave surface of the arc faces the second slot wall.

[0007] In some embodiments, in a cross-section perpendicular to the axis of the rotor core, the center lines of the first and second slot walls coincide, and the distance L between the two end points of the first slot wall is equal to the length L2 of the second slot wall.

[0008] In some embodiments, in a cross-section perpendicular to the axis of the rotor core, the arc length of the first groove wall is L1, and the maximum distance between the first groove wall and the second groove wall is H; wherein, L1 / H = 2.293 to 2.313.

[0009] In some embodiments, in a cross-section perpendicular to the axis of the rotor core, the length of the second groove wall is L2, and the maximum distance between the first groove wall and the second groove wall is H; wherein, L2 / H = 2.09 to 2.15.

[0010] In some embodiments, the included angle between the second groove walls of two magnet grooves in the magnet groove group is D; wherein, 75.2° ≤ D ≤ 80.8°.

[0011] In some embodiments, the middle part of the rotor core has a shaft hole, and each magnet groove group is arranged around the shaft hole; one end of the rotor core at the shaft hole is provided with a counterbore for avoiding the cylinder seat of the compressor; the aperture of the shaft hole is smaller than the aperture of the counterbore;

[0012] Wherein, the aperture of the counterbore is R1, and the outer diameter of the rotor core is R2, wherein, R2 / 2 > R1 / 2 + (L2 * cos(D / 2)).

[0013] In some embodiments, the rotor core is provided with grooves between each two adjacent magnet groove groups.

[0014] The present invention also provides a rotor, which includes the rotor core described in any one of the above.

[0015] The present invention also provides a motor, which includes the rotor core described in any one of the above; or includes the rotor described in the above.

[0016] The present invention also provides a compressor, which includes the rotor core described in any one of the above; or includes the rotor described in the above; or includes the motor described in the above.

[0017] A rotor core, a rotor, a motor and a compressor provided by the present invention have the following beneficial effects:

[0018] 1. Compared with the rectangular magnet slot design in the prior art, the present invention maintains the design of the second slot wall structure of the existing rectangular magnet slot and designs the first slot wall opposite to the excitation surface of the magnet as an arc. In this way, the structural cooperation between the first slot wall and the second slot wall can not only increase the magnet usage and thickness under the limited available area of the rotor, obtaining a larger magnetic energy product, but also the arc design can increase the excitation area of the magnet. Among them, the combination of a larger magnetic energy product and a larger excitation area can improve the magnetic concentration ability of the magnet in the magnet slot, achieve a better magnetic concentration effect, provide a larger magnetic flux, reduce the magnetic leakage of the motor, thereby increasing the back electromotive force of the motor, increasing the torque output per unit current, reducing the copper loss of the motor, and improving the power density and motor efficiency.

[0019] 2. The solution of the present invention can improve the peak-to-peak value of the cogging torque of the motor and enhance the motor performance while retaining the counterbore structure.

[0020] 3. The solution of the present invention can also effectively reduce the content of specific harmonics of the back electromotive force and the torque ripple, and optimize the motor performance.

[0021] 4. Compared with the conventional rotor structure, the solution of the present invention has an improved effect on the motor performance and operation stability, and the rotor structure strength has not changed significantly. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. The drawings in the following description are only exemplary. For those of ordinary skill in the art, without creative efforts, other implementation drawings can be obtained according to the provided drawings.

[0023] Figure 1 is a schematic structural diagram of a conventional rotor core;

[0024] Figure 2 is a schematic structural diagram of a rotor core provided by an embodiment of the present invention;

[0025] Figure 3 is a schematic diagram of the dimensions of the counterbore side of the rotor core;

[0026] Figure 4 is an assembly schematic diagram of the rotor core and the magnet;

[0027] Figure 5 is a schematic structural diagram of a rotor provided by an embodiment of the present invention;

[0028] Figure 6 shows a comparison diagram of the copper loss of the motor between the solution of the present invention and the conventional solution;

[0029] Figure 7 Shows a comparison chart of the motor efficiency between the solution of the present invention and the conventional solution;

[0030] Figure 8 Shows a comparison chart of the cogging torque of the motor between the solution of the present invention and the conventional solution;

[0031] Figure 9 Shows a comparison chart of the harmonic content of the air-gap magnetic flux density of the motor cogging torque between the solution of the present invention and the conventional solution.

[0032] The reference numerals are:

[0033] 1, rotor core; 2, permanent magnet slot group; 3, rivet through-hole; 4, shaft hole; 5, counterbore; 6, groove; 7, permanent magnet; 8, baffle; 9, rivet; 20, permanent magnet slot; 21, first slot wall; 22, second slot wall. Detailed implementation manners

[0034] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and in no way limits the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0035] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the orientation words such as "front, rear, upper, lower, left, right", "horizontal, vertical, perpendicular, horizontal" and "top, bottom" is usually based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description. Without contrary description, these orientation words do not indicate and imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the protection scope of the present invention; the orientation words "inside, outside" refer to the inside and outside relative to the contour of each component itself.

[0036] For ease of description, spatial relative terms such as "above", "over", "on the upper surface", "upper" etc. can be used here to describe the spatial positional relationship of a device or feature shown in the figure with other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation in addition to the orientation described in the figure for the device. For example, if the device in the attached drawing is inverted, the device described as "above or over other devices or structures" will then be positioned as "below or under other devices or structures". Thus, the exemplary term "above" can include both the orientations of "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and corresponding interpretations are made for the spatial relative descriptions used here.

[0037] In addition, it should be noted that the use of terms such as "first", "second" etc. to define components is only for the convenience of differentiating the corresponding components. Without additional statements, the above terms have no special meanings, and thus should not be construed as limiting the protection scope of the present invention.

[0038] Referring jointly to Figure 2-4 As shown, according to an embodiment of the present invention, a rotor core 1 is provided. The rotor core 1 has two or more magnet slots groups 2 arranged at equal intervals circumferentially. Each magnet slots group 2 has two magnet slots 20 distributed in a V shape. The two magnet slots 20 can be symmetrically distributed for convenient processing.

[0039] Each of the above-mentioned magnet slots 20 has opposite first slot wall 21 and second slot wall 22, and the first slot wall 21 is used to face the excitation surface of the magnet 7 in the magnet slot 20. Among them, in a cross-section perpendicular to the axis of the rotor core 1, the second slot wall 22 in the magnet slot 20 is linear, and the first slot wall 21 is arc-shaped, and the concave surface of the arc faces the second slot wall 22.

[0040] Compared with the rectangular magnet slot design in the prior art, the present invention maintains the structural design of the second slot wall 22 of the existing rectangular magnet slot, and designs the first slot wall 21 facing the excitation surface of the magnet 7 as arc-shaped. Thus, the structural cooperation between the first slot wall 21 and the second slot wall 22 can not only increase the magnet usage amount and thickness under the limited available area of the rotor, obtaining a larger magnetic energy product, but also the arc-shaped design can increase the excitation area of the magnet 7. Among them, the cooperation of the larger magnetic energy product and the larger excitation area can improve the magnetic concentration ability of the magnet 7 in the magnet slot 20, achieve a better magnetic concentration effect, provide a larger magnetic flux, reduce the magnetic leakage of the motor, thereby improving the back electromotive force of the motor, increasing the torque output per unit current, reducing the copper loss of the motor, and improving the power density and motor efficiency.

[0041] In addition, compared with the rectangular magnet groove design in the prior art, the structural cooperation between the first groove wall 21 and the second groove wall 22 of the present invention can also obtain greater magnetic steel structure strength and improve the demagnetization resistance of the magnetic steel. Moreover, by maintaining the structural design of the second groove wall 22 of the existing rectangular magnet groove, the present invention will not affect the magnetic leakage between magnetic poles and the structural strength of the rotor core 1.

[0042] In some embodiments, as Figure 2 shown, a groove 6 is provided between the outer walls of the aforementioned rotor core 1 between each adjacent two magnet groove groups 2, and the design of this groove 6 is beneficial to reducing the inter-pole magnetic leakage coefficient.

[0043] In some embodiments, as Figure 2-3 shown, in a cross-section perpendicular to the axis of the rotor core 1, the center lines of the first groove wall 21 and the second groove wall 22 coincide, and the distance L between the connection lines of the two end points of the first groove wall 21 is equal to the length L2 of the second groove wall 22.

[0044] In the above example, through the above structural limitation, the magnet 7 in the magnet groove 20 forms a generally rectangular shape, which is beneficial to processing.

[0045] In some embodiments, as Figure 2-3 shown, in a cross-section perpendicular to the axis of the rotor core 1, the arc length of the first groove wall 21 is L1, and the maximum distance between the first groove wall 21 and the second groove wall 22 is H. Among them, L1 / H = 2.293 - 2.313. Preferably, L1 / H = 2.303.

[0046] In the above example, the maximum distance between the first groove wall 21 and the second groove wall 22 is sometimes also referred to as the width of the magnet groove 20. Among them, by making L1 / H = 2.293 - 2.313, within this range, the excitation area of the magnet 7 can be further increased, achieving a better magnetic focusing effect, thereby further improving the back electromotive force of the motor, increasing the torque output per unit current, further reducing the copper loss of the motor, and further improving the efficiency of the motor.

[0047] In some embodiments, as Figure 2-3 shown, in a cross-section perpendicular to the axis of the rotor core 1, the length of the second groove wall 22 is L2, and the maximum distance between the first groove wall 21 and the second groove wall 22 is H. Among them, L2 / H = 2.09 - 2.15. Preferably, L2 / H = 2.12.

[0048] In the above example, by making L2 / H = 2.09 - 2.15, within this range, the thickness of the permanent magnet 7 in the permanent magnet slot 20 can be reasonably designed, the utilization rate of the permanent magnet 7 can be increased, the waste of cost can be avoided, and at the same time, the rotor can obtain a larger magnetic energy product, so that the back electromotive force of the motor is further increased, the copper loss is further reduced, and the motor efficiency is further improved.

[0049] In some embodiments, as Figure 2-3 shown, the included angle of the second groove walls 22 of the two permanent magnet slots 20 in the aforementioned permanent magnet slot group 2 is D; wherein, 75.2° ≤ D ≤ 80.8°. Preferably, D = 78°.

[0050] In the above example, by making 75.2° ≤ D ≤ 80.8°, within this range, the magnetic circuit path is more optimal, and the peak-to-peak value of the cogging torque and the harmonic content of the air-gap magnetic density can be reduced. Among them, reducing the peak-to-peak value of the cogging torque is beneficial to improving the performance of the motor and making the motor operate more smoothly; reducing the harmonic content of the air-gap magnetic density helps to reduce the iron loss of the motor and improve the motor efficiency.

[0051] In some embodiments, as Figure 2 shown, the middle part of the aforementioned rotor core 1 has a shaft hole 4, and the aforementioned permanent magnet slot groups 2 are arranged around the shaft hole 4. One end of the aforementioned rotor core 1 at the shaft hole 4 is provided with a counterbore 5 for avoiding the cylinder seat of the compressor. The aperture of the shaft hole 4 is smaller than the aperture of the counterbore 5. Among them, the aperture of the counterbore 5 is R1, and the outer diameter of the rotor core 1 is R2, wherein, R2 / 2 > R1 / 2 + (L2 * cos(D / 2)).

[0052] In the above example, by making R2 / 2 > R1 / 2 + (L2 * cos(D / 2)), this range can ensure that the rotor structure strength is basically the same as that of a conventional V-shaped rotor of the same size in the presence of the counterbore 5; at the same time, it can also reduce the rotor magnetic leakage, optimize the magnetic circuit path, and further improve the back electromotive force of the motor.

[0053] In some embodiments, as Figure 2 shown, the center line of the aforementioned counterbore 5 coincides with the axis of the shaft hole 4, so that the force on the rotor core 1 is more uniform and the rotor core 1 has better structural strength.

[0054] The structural design of the counterbore 5 on the above-mentioned rotor core 1 affects the distribution of the magnet slots 20, and has an impact on the back electromotive force, cogging torque, and air-gap magnetic density of the motor. As a very important parameter of the permanent magnet synchronous motor, the back electromotive force of the motor affects both the dynamic and steady-state performance of the motor. There are harmonic contents in the back electromotive force of the motor, which affect the performance of the motor. How to reduce the harmonic content of the back electromotive force of the motor is a key to improving the performance of the motor. The cogging torque of the motor will cause torque pulsation, which will in turn lead to speed fluctuations and also have a certain impact on the vibration and noise of the motor. Reducing the peak-to-peak value of the cogging torque is beneficial to improving the performance and stable operation of the motor. The air gap is the gap between the stator and rotor of the motor. When the motor rotates, a magnetic density will be generated in the gap, which becomes the air-gap magnetic density. Due to the cooperation between the stator teeth and the rotor, certain air-gap magnetic density harmonics will be generated, which is not conducive to the performance of the motor.

[0055] Among them, in the solution of the present invention, by making L1 / H = 2.293 to 2.313, and making L2 / H = 2.09 to 2.15, and making 75.2° ≤ D ≤ 80.8°, and making R2 / 2 > R1 / 2 + (L2 * cos(D / 2)), the back electromotive force of the motor can be improved, the torque output per unit current can be increased, the copper loss of the motor can be reduced, and the power density and efficiency of the motor can be improved; it can also increase the peak-to-peak value of the cogging torque of the motor while retaining the structure of the counterbore 5, and improve the performance of the motor; it can also effectively reduce the content of specific harmonics of the back electromotive force and torque pulsation, and optimize the performance of the motor; in addition, compared with the conventional rotor structure, the solution of the present invention has an improved effect on the performance and operation stability of the motor, and the strength of the rotor structure has not changed significantly.

[0056] Figure 6 A comparison chart of the copper loss of the motor between the solution of the present invention and the conventional solution is shown. Figure 7 A comparison chart of the efficiency of the motor between the solution of the present invention and the conventional solution is shown. Figure 8 A comparison chart of the cogging torque of the motor between the solution of the present invention and the conventional solution is shown. Figure 9 A comparison chart of the harmonic content of the cogging torque and air-gap magnetic density of the motor between the solution of the present invention and the conventional solution is shown. Among them, Figures 6-9 In the solution of the present invention: in the cross-section perpendicular to the axis of the rotor core 1, the second groove wall 22 is straight, the first groove wall 21 is arc-shaped, and the concave surface of the arc faces the second groove wall 22; and L1 / H = 2.293 to 2.313, and L2 / H = 2.09 to 2.15, and 75.2° ≤ D ≤ 80.8°, and R2 / 2 > R1 / 2 + (L2 * cos(D / 2)). Figures 6-9 In the conventional solution: both of the two magnet slots 20 distributed in a V shape in the magnet slot group 2 of the rotor core 1 are rectangular slots. As Figure 6 shown, the copper loss of the solution of the present invention is significantly reduced in the speed range of 1320 rpm to 3000 rpm. AsFigure 7 As shown, the motor efficiency of the solution of the present invention is optimized in the rotational speed range of 1320 rpm to 3000 rpm, and the improvement ratio in the medium and low frequency bands is more obvious than that in the high frequency band. As Figure 8 shown, comparing the peak-to-peak value of the cogging torque between the solution of the present invention and the conventional solution, the peak-to-peak value of the cogging torque of the solution of the present invention is significantly reduced, which optimizes the motor performance and makes the operation more stable. As Figure 9 shown, comparing the harmonic content of the air-gap magnetic density between the solution of the present invention and the conventional solution, the harmonic content of the air-gap magnetic density of the solution of the present invention is greatly reduced, effectively improving the motor performance and efficiency, and reducing the vibration, noise and loss caused by harmonics.

[0057] It should be noted here that: the above-mentioned rotor core 1 can be formed by laminating rotor punching sheets, or can be an integrally formed structure. When the rotor core 1 is formed by laminating rotor punching sheets, the rotor punching sheets can be cut from silicon steel sheets by wire cutting process. The rotor punching sheets can also be formed by stamping through a rotor punching die. In the rotor punching die, the punched rotor punching sheets are pressed and fixed at a certain height to form a complete rotor core 1. The single sheets of such rotor core 1 are fixed by card slots. After forming the complete rotor core 1 by stamping, the two side baffles 8 are fixed with rivets 9 after putting in the permanent magnets 7, and then the permanent magnets 7 inside the rotor are magnetized by a magnetizing coil.

[0058] As Figure 5 shown, the present invention also provides a rotor, which may include the rotor punching sheets described in any one of the above; or include the rotor core 1 described in the above. Among them, due to the adoption of the above-mentioned rotor punching sheets or rotor core 1, the magnetic concentration ability can be improved, achieving a better magnetic concentration effect, thereby increasing the back electromotive force of the motor, increasing the torque output per unit current, reducing the copper loss of the motor, and improving the motor efficiency.

[0059] In some embodiments, as Figure 5 shown, the rotor further includes a baffle 8, a rivet 9 and a permanent magnet 7. The number of the permanent magnets 7 is equal to the number of the magnet slots 20, and each permanent magnet 7 is correspondingly arranged in the corresponding magnet slot 20. The number of the baffles 8 is two. One baffle 8 is arranged at one axial end of the rotor core 1 to stop and limit one end of the permanent magnets 7 in each magnet slot 20. The other baffle 8 is arranged at the other axial end of the rotor core 1 to stop and limit the other end of the permanent magnets 7 in each magnet slot 20. The number of the rivets 9 is more than two, and the rotor core 1 is provided with rivet through holes 3; the rivets 9 pass through the rivet through holes 3 to fix the rotor core 1 and the two baffles 8 together.

[0060] In some embodiments, the number of the foregoing magnet slot groups 2 may be 6, and the permanent magnets 7 in each magnet slot group 2 form a magnetic pole, so that the rotor has 6 magnetic poles.

[0061] The actual height of the above-mentioned rotor core 1 is determined by the height of the stator core of the piston compressor, and the height of the counterbore section of the rotor core 1 is determined by the cylinder block. After determining the height, after magnetizing the permanent magnet 7 and correspondingly placing it into the magnet slot 20, baffles 8 are installed on both sides of the rotor core 1 and fixed with rivets 9. The baffles 8 on both sides can effectively prevent the axial displacement of the permanent magnet 7, and thus the assembly of the rotor is completed.

[0062] The present invention also provides a motor, which may include the rotor punching sheet described in any one of the above; or include the rotor core 1 described in the above; or include the rotor described in the above. Among them, due to the adoption of the above rotor punching sheet or rotor core 1 or rotor by the motor, the magnetic concentration ability can be improved, achieving a better magnetic concentration effect, thereby the back electromotive force of the motor can be increased, the torque output per unit current can be increased, the copper loss of the motor can be reduced, and the efficiency of the motor can be improved.

[0063] In some embodiments, the above-mentioned motor may be a permanent magnet synchronous motor.

[0064] The present invention also provides a compressor, which may include the rotor punching sheet described in any one of the above; or include the rotor core 1 described in the above; or include the rotor described in the above; or include the motor described in the above. Among them, due to the adoption of the above rotor punching sheet or rotor core 1 or rotor or motor by the compressor, the magnetic concentration ability can be improved, achieving a better magnetic concentration effect, thereby the back electromotive force of the motor can be increased, the torque output per unit current can be increased, the copper loss of the motor can be reduced, and the efficiency of the motor can be improved.

[0065] In some embodiments, the above-mentioned compressor may be a piston compressor.

[0066] It is easy for those skilled in the art to understand that, on the premise of no conflict, the advantageous technical features of the above-mentioned various embodiments can be freely combined and superimposed.

[0067] The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention. The above is only the preferred implementation manner of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and modifications can still be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A rotor core, characterized in that: The rotor core (1) has two or more magnet slot groups (2) evenly spaced in the circumferential direction. Each magnet slot group (2) has two magnet slots (20) distributed in a V shape. Each magnet slot (20) has opposite first slot walls (21) and second slot walls (22), and the first slot wall (21) is used to face the excitation surface of the magnet (7) in the magnet slot (20). Wherein, in a cross-section perpendicular to the axis of the rotor core (1), the second slot wall (22) in the magnet slot (20) is linear, and the first slot wall (21) is arc-shaped, and the concave surface of the arc faces the second slot wall (22).

2. The rotor core (1) according to claim 1, characterized in that: In a cross-section perpendicular to the axis of the rotor core (1), the center lines of the first slot wall (21) and the second slot wall (22) coincide, and the distance L between the two end points of the first slot wall (21) is equal to the length L2 of the second slot wall (22).

3. The rotor core (1) according to claim 1 or 2, characterized in that: In a cross-section perpendicular to the axis of the rotor core (1), the arc length of the first slot wall (21) is L1, and the maximum distance between the first slot wall (21) and the second slot wall (22) is H; wherein, L1 / H = 2.293 - 2.

313.

4. The rotor core (1) according to claim 1 or 2, characterized in that: In a cross-section perpendicular to the axis of the rotor core (1), the length of the second slot wall (22) is L2, and the maximum distance between the first slot wall (21) and the second slot wall (22) is H; wherein, L2 / H = 2.09 - 2.

15.

5. The rotor core (1) according to claim 1 or 2, characterized in that: The included angle between the second slot walls (22) of the two magnet slots (20) in the magnet slot group (2) is D; wherein, 75.2° ≤ D ≤ 80.8°.

6. The rotor core (1) according to claim 1 or 2, characterized in that: The middle part of the rotor core (1) has a shaft hole (4), and each magnet slot group (2) is arranged around the shaft hole (4); a counterbore (5) for avoiding the cylinder seat of the compressor is provided at one end of the shaft hole (4) of the rotor core (1); the aperture of the shaft hole (4) is smaller than the aperture of the counterbore (5); Wherein, the aperture of the counterbore (5) is R1, and the outer diameter of the rotor core (1) is R2, wherein, R2 / 2 > R1 / 2 + (L2 * cos(D / 2)).

7. The rotor core (1) according to claim 1 or 2, characterized in that: A groove (6) is provided between each two adjacent magnet slot groups (2) of the rotor core (1).

8. A rotor, characterized in that: Including the rotor core (1) according to any one of claims 1 - 7.

9. A motor, characterized in that: Including the rotor core (1) according to any one of claims 1 - 7; or including the rotor according to claim 8.

10. A compressor, characterized in that: Comprising the rotor core (1) according to any one of claims 1-7; or comprising the rotor according to claim 8; or comprising the electric machine according to claim 9.

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