Motor and compressor

Abstract

The utility model discloses a motor and a compressor, the compressor comprises a motor, and the motor comprises a rotor, a permanent magnet and a stator. The rotor is provided with a plurality of first through holes arranged at intervals in the circumferential direction of the rotor and a plurality of magnet grooves arranged at intervals in the circumferential direction of the rotor, the first through holes and the magnet grooves are arranged in a penetrating mode in the axis direction of the rotor, and the first through holes extend by a preset length in the circumferential direction of the rotor. The magnet grooves are formed in the sides, close to the outer circumferential face of the rotor, of the first through holes and communicate with the first through holes, all the magnet grooves extend in the radial direction of the rotor, the two ends, in the circumferential direction of the rotor, of one first through hole communicate with one magnet groove correspondingly, and the two magnet grooves communicating with the same first through hole are symmetrically formed along the center line of the first through hole. The multiple permanent magnets are embedded in the multiple magnet grooves in a one-to-one correspondence mode. The stator is provided with a second through hole, and the stator sleeves the periphery of the rotor through the second through hole. The problem of poor back electromotive force sine of the motor in the prior art is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of refrigeration equipment, in particular to a motor and a compressor. BACKGROUND

[0002] In the motor of the existing compressor, the magnet slot formed on the motor is usually in a linear or V-shaped type. The V-shaped magnet slot can make the motor have strong anti-demagnetization ability, reduce the thickness of the magnet, and further reduce the production cost of the motor. However, due to the zero-one distribution of the magnetic density distribution in the air gap of the motor with the V-shaped magnet slot, the sine of the back electromotive force of the motor is poor, which affects the overall performance of the motor. CONTENT OF THE UTILITY MODEL

[0003] The main purpose of the present application is to provide a motor and a compressor to at least solve the problem of poor sine of the back electromotive force of the motor in the prior art.

[0004] According to one aspect of the present application, a motor is provided, comprising:

[0005] A rotor, a plurality of first through holes and a plurality of magnet slots are formed on the rotor and are arranged at intervals in the circumferential direction of the rotor. The first through holes and the magnet slots are both arranged in the axial direction of the rotor. The first through holes extend in the circumferal direction of the rotor by a predetermined length. The magnet slots are arranged on the side of the first through holes close to the outer circumferential surface of the rotor and communicate with the first through holes. Each of the magnet slots extends in the radial direction of the rotor. One first through hole is connected to one magnet slot at each end in the circumferential direction of the rotor. Two magnet slots connected to the same first through hole are symmetrically arranged about the center line of the first through hole.

[0006] A plurality of permanent magnets are embedded in the plurality of magnet slots one by one.

[0007] A stator is provided with a second through hole. The stator is sleeved on the outer circumferential surface of the rotor through the second through hole.

[0008] Further, a plurality of thinned portions and a plurality of rotor slots are formed at intervals on the outer circumferential surface of the rotor. The rotor slots are arranged one by one corresponding to the magnet slots.

[0009] The two sides of the rotor slot in the circumferential direction of the rotor are provided with the thinned portions, and the minimum distance from the rotor slot to the axis of the rotor is smaller than the minimum distance from the thinned portion to the axis of the rotor.

[0010] Further, a minimum distance g1 between the outer circumferential surface of the rotor and the inner wall surface of the second through hole and a maximum distance g2 between the rotor slot and the inner wall surface of the second through hole satisfy the relationship: 2.5≤g2 / g1≤3.5; wherein 0.45mm≤g1≤0.55mm.

[0011] Further, two thinning portions are arranged between two adjacent rotor slots, and an arc surface is arranged between the two thinning portions, and a central angle B corresponding to the arc surface satisfies the relationship: 19°≤B≤21°.

[0012] Further, the rotor slot extends to the outer circumferential surface of the rotor, and a central angle C corresponding to the arc length of the two opposite side walls of the rotor slot across the outer circumferential surface of the rotor satisfies the relationship: 14°≤C≤16°.

[0013] Further, a minimum distance H between the magnet slot and the rotor slot satisfies the relationship: 0.4mm≤H≤0.7mm.

[0014] Further, the stator comprises a plurality of stator teeth, and the plurality of stator teeth are arranged at the side of the stator close to the rotor, and a plurality of tooth slots are arranged at the side of the stator teeth close to the outer circumferential surface of the rotor.

[0015] Further, the stator teeth comprise two tooth slots arranged at the side of the stator teeth close to the outer circumferential surface of the rotor, and the two tooth slots on the same stator tooth are symmetrically arranged along the center line of the stator tooth.

[0016] Further, along the axial direction of the stator, the central angle A between the first straight line and the second straight line in the cross section obtained by cutting the stator along a direction perpendicular to the axial direction of the stator satisfies the relationship: 9°≤A≤11°.

[0017] Further, the maximum depth of the tooth slot is g3, and the minimum distance between the outer circumferential surface of the rotor and the inner wall surface of the second through hole is g1, wherein the relationship between g3 and g1 satisfies the relationship: 0.9≤g1 / g3≤1.1.

[0018] Further, the stator teeth comprise 12 stator teeth, and one stator slot is arranged between two adjacent stator teeth, and the permanent magnet comprises 8 permanent magnets.

[0019] On the other hand, the application also provides a compressor, and the compressor comprises the motor described above.

[0020] Compared with the prior art, in the application, one first through hole is communicated with one magnet slot at each end along the circumference of the rotor, and the two magnet slots communicated on the same first through hole are symmetrically arranged along the center line of the first through hole, and the two magnet slots both extend along the radial direction. That is to say, the permanent magnets in the two magnet slots are arranged in a V shape along the radial direction, and after the magnetic force lines of the permanent magnets pass out of the rotor, most of the magnetic force lines are gathered at the air gap between the rotor and the stator corresponding to the radial direction of the first through hole, and a small part of the magnetic force lines are located at the air gap corresponding to the magnet slot, which means that the magnetic induction intensity of the magnetic field in the air gap corresponding to the radial direction of the first through hole is large, the magnetic induction intensity of the magnetic field in the air gap corresponding to the radial direction of the magnet slot is low, and the farther away from the position at the air gap corresponding to the radial direction of the first through hole, the magnetic field in the air gap gradually decreases, and gradually increases to the air gap corresponding to the radial direction of the next first through hole in the circumferential direction. This means that along the circumferential direction of the air gap, the magnetic induction intensity of the magnetic field in the air gap gradually decreases first and then gradually increases, so that the magnetic density in the air gap conforms to the sinusoidal distribution, and when the magnetic density in the air gap conforms to the sinusoidal distribution, the peak value of the anti-electromotive force harmonic generated by the magnetic field in the air gap acting on the stator is low, at this time, the influence of the harmonic on the fundamental wave is small, the waveform distortion rate of the anti-electromotive force is low, and finally the waveform graph of the anti-electromotive force tends to be sinusoidal, thereby improving the overall performance of the motor. BRIEF DESCRIPTION OF DRAWINGS

[0021] The drawings described herein are used to provide further understanding of the present application, constitute a part of the present application, the illustrative embodiments of the present application and the description thereof are used to explain the present application, and do not constitute improper limitation on the present application. In the drawings:

[0022] Figure 1 It is a structural schematic diagram of the motor disclosed in the present application;

[0023] Figure 2 It is Figure 1 It is an enlarged schematic diagram of the I area in the middle;

[0024] Figure 3 It is a schematic diagram of the relationship between the g2 / g1 ratio and the waveform distortion rate of the back electromotive force;

[0025] Figure 4 It is a back electromotive force waveform schematic diagram of the motor with no tooth slot on the stator tooth and the motor with tooth slot on the stator tooth.

[0026] Among the above drawings, the following reference signs are included:

[0027] 10 rotor; 11 first through hole; 12 magnet slot; 13 thinning portion; 14 rotor slot; 15 arc surface; 20 stator; 21 stator tooth; 22 stator slot; 30 permanent magnet; 40 second through hole; 41 air gap; 50 mounting hole; 211 tooth slot. DETAILED DESCRIPTION

[0028] It should be noted that the embodiments and features of the embodiments in the present application can be combined with each other without conflict. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0029] It should be noted that the terms used herein are only intended to describe specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, the singular form is intended to include the plural form, unless the context clearly indicates otherwise, and it should also be understood that the terms "comprise" and / or "include" as used in the specification indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0030] Unless specifically stated otherwise, the relative arrangements of components and steps illustrated in these embodiments and the numerical expressions and values set forth in the examples are not meant to limit the scope of the present application. It should also be understood that the size of the various parts shown in the figures can not be to scale and that the dimensions of the various parts can be arbitrarily changed. Techniques, methods, and devices known to those of ordinary skill in the relevant art can not be discussed in detail, but should be considered as part of the present disclosure. In all examples shown and discussed herein, any specific value should be interpreted as merely an example, and not as a limitation. Therefore, other examples of the exemplary embodiments can have different values. It should be noted that similar reference numbers and letters in the following drawings represent similar items, and therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0031] Reference is made to Figures 1 to 4 As shown, according to the embodiments of the present application, a compressor is provided, which includes a motor including a rotor 10, a permanent magnet 30 and a stator 20.

[0032] The rotor 10 is provided with a plurality of first through holes 11 and a plurality of magnet grooves 12, which are arranged at intervals in the circumferential direction of the rotor 10, the first through holes 11 and the magnet grooves 12 are arranged in the axial direction of the rotor 10, the first through holes 11 extend in the circumferential direction of the rotor 10 by a predetermined length, the magnet grooves 12 are arranged on the side of the first through holes 11 close to the outer circumferential surface of the rotor 10 and communicate with the first through holes 11, each of the magnet grooves 12 extends in the radial direction of the rotor 10, and one first through hole 11 is respectively communicated with one magnet groove 12 at both ends in the circumferential direction of the rotor 10, and the two magnet grooves 12 communicated with the same first through hole 11 are symmetrically arranged along the center line of the first through hole 11. The permanent magnets 30 include a plurality of permanent magnets 30, and the plurality of permanent magnets 30 are correspondingly embedded in the plurality of magnet grooves 12. The stator 20 is provided with a second through hole 40, and the stator 20 is sleeved on the outer circumferential surface of the rotor 10 through the second through hole 40. As shown in the accompanying drawings, the center line of the first through hole 11 is m4. Figure 1

[0033] Specifically, in the embodiment, one first through hole 11 is respectively communicated with one magnet groove 12 at both ends in the circumferential direction of the rotor 10, and the two magnet grooves 12 communicated with the same first through hole 11 are symmetrically arranged along the center line of the first through hole 11, and the two magnet grooves 12 both extend in the radial direction. That is to say, the permanent magnets 30 in the two magnet grooves 12 are arranged in a V shape in the radial direction, and after the magnetic lines of the permanent magnets 30 pass through the rotor 10, most of the magnetic lines are gathered at the air gap 41 between the rotor 10 and the stator 20 corresponding to the radial direction of the first through hole 11, and a small part of the magnetic lines are located at the air gap 41 corresponding to the magnet groove 12, which means that the magnetic induction intensity of the magnetic field in the air gap 41 corresponding to the radial direction of the first through hole 11 is large, the magnetic induction intensity of the magnetic field in the air gap 41 corresponding to the radial direction of the magnet groove 12 is low, and the farther away from the position of the air gap 41 corresponding to the radial direction of the first through hole 11, the lower the magnetic field in the air gap 41, and in the circumferential direction, the closer to the air gap 41 corresponding to the radial direction of the next first through hole 11, the magnetic field in the air gap 41 gradually increases. This means that in the circumferential direction, the magnetic induction intensity (magnetic density) of the magnetic field in the air gap 41 first gradually decreases and then gradually increases, so that the magnetic density in the air gap 41 conforms to the sinusoidal distribution, and when the magnetic density in the air gap 41 conforms to the sinusoidal distribution, the peak value of the inverse electromotive force harmonic generated by the magnetic field in the air gap 41 acting on the stator 20 is low, at this time, the influence of the harmonic on the fundamental wave is small, the waveform distortion rate of the inverse electromotive force is low, and finally the waveform of the inverse electromotive force tends to be sinusoidal, thereby improving the overall performance of the motor.

[0034] ​Compared with the prior art V-shaped magnet slot 12, the prior art V-shaped magnet slot 12 is connected by two magnet slots 12, so that the magnetic lines of the permanent magnet 30 are concentrated at the V-shaped opening, which causes the magnetic density in the corresponding air gap 41 in the radial direction of the V-shaped opening to be almost the same, that is, the magnetic density in the air gap 41 tends to be zero distribution, which causes the peak value of the harmonic of the back electromotive force to be large, and further causes the waveform of the back electromotive force to tend to be trapezoidal. On the other hand, since the first through hole 11 is formed on the side of the magnet slot 12 away from the outer circumferential surface of the rotor 10, the magnetic induction lines emitted by the magnet slot 12 cannot pass through the first through hole 11 along the axis direction close to the rotor 10, thereby reducing the leakage magnetic flux generated by the motor.

[0035] Further, a plurality of thinning portions 13 and a plurality of rotor slots 14 are arranged on the outer circumferential side of the rotor 10, and the rotor slots 14 are arranged one-to-one with the magnet slots 12; wherein the two sides of the rotor slot 14 in the circumferential direction of the rotor 10 are provided with the thinning portion 13, and the minimum distance from the rotor slot 14 to the axis of the rotor 10 is smaller than the minimum distance from the thinning portion 13 to the axis of the rotor 10.

[0036] Specifically, after the magnetic lines emitted by the permanent magnet 30 pass through the thinning portion 13 and the rotor slot 14, part of the magnetic lines will change direction, and the magnetic field generated by this part of the magnetic lines in the air gap 41 will not induce an electromotive force on the stator 20, that is, the effective magnetic field strength formed in the air gap 41 corresponding to the thinning portion 13 and the rotor slot 14 is reduced. In addition, in the present embodiment, the two sides of the rotor slot 14 in the circumferential direction of the rotor 10 are provided with the thinning portion 13, and the minimum distance from the rotor slot 14 to the axis of the rotor 10 is smaller than the minimum distance from the thinning portion 13 to the axis of the rotor 10. That is, the recess depth of the rotor slot 14 in the axis direction is greater than the thinning thickness of the thinning portion 13, which means that the magnetic density in the air gap 41 corresponding to the thinning portion 13 is higher than the magnetic density in the air gap 41 corresponding to the rotor slot 14, and finally the magnetic density of the air gap 41 gradually decreases from the air gap 41 corresponding to the first through hole 11 to the air gap 41 corresponding to the rotor slot 14, so that the magnetic density in the air gap 41 tends to be sinusoidal distribution. On the other hand, the rotor slot 14 of the present application is arranged one-to-one with the magnet slot 12, that is, the extension line of the magnet slot 12 in the radial direction passes through the rotor slot 14. One advantage of this arrangement is to reduce the spacing between the magnet slot 12 and the rotor slot 14. When the spacing between the magnet slot 12 and the rotor slot 14 is too large, the magnetic lines are more likely to enter the air gap 41 and close after passing through the stator 20, resulting in increased leakage magnetic flux of the motor. Therefore, reducing the spacing between the magnet slot 12 and the rotor slot 14 can prevent the magnetic lines from more easily entering the stator 20, resulting in increased leakage magnetic flux of the motor.

[0037] Further, the minimum distance g1 between the outer circumferential surface of the rotor 10 and the inner wall surface of the second through hole 40 and the maximum distance g2 between the rotor slot 14 and the inner wall surface of the second through hole 40 satisfy the relationship: 2.5≤g2 / g1≤3.5; wherein 0.45mm≤g1≤0.55mm.

[0038] In the present embodiment, if the maximum distance g2 between the rotor slot 14 and the inner wall surface of the second through hole 40 is too large, for example, g2 / g1>3.5, the magnetic density in the air gap 41 corresponding to the rotor slot 14 will decrease too much relative to the magnetic density in the air gap 41 corresponding to the thinning portion 13, which will eventually result in a lower peak value of the back electromotive force at a certain moment, thereby affecting the performance of the motor, for example, reducing the efficiency of the motor; meanwhile, if the maximum distance between the rotor slot 14 and the outer circumferential surface of the rotor 10 is too large, i.e., the rotor slot 14 is too deep, which will affect the rigidity of the rotor 10. If g2 / g1 is too small, for example, g2 / g1<2.5, the magnetic density in the air gap 41 corresponding to the rotor slot 14 will be less different from the magnetic density in the air gap 41 corresponding to the thinning portion 13, in which case the peak value of the harmonic in the back electromotive force will be larger, and the probability of waveform distortion of the back electromotive force will be higher. In order to make the peak value of the back electromotive force moderate, the value of g1 in the present embodiment should be set between 0.45mm and 0.55mm. The size of g1 determines the size of the peak value of the back electromotive force, when g1 is small, the back electromotive force generated on the stator 20 is large, and when g1 is large, the back electromotive force generated on the stator 20 is small. If the back electromotive force is too large, it will cause the temperature rise of the motor to be too high, resulting in overheating of the motor, and if the back electromotive force is too low, it will cause the efficiency of the motor to be low, and the service life of the motor to decrease. Therefore, when the value of g1 is set between 0.45mm and 0.55mm, the peak value of the back electromotive force in the motor is moderate. The value of g1 can be 0.45mm, 0.46mm, 0.47mm, 0.48mm, 0.49mm, 0.5mm, 0.51mm, 0.52mm, 0.53mm, 0.54mm and 0.55mm. The value of g2 / g1 can be 3, 3.2, 3.4, 3.6, 3.8 and 4.

[0039] In other conditions being the same, the present application also gives some specific embodiments to illustrate the influence of g2 / g1 on the sinusoidalization of the back electromotive force waveform:

[0040] Comparative Example 1:

[0041] g2 / g1 is 1, in which case the waveform distortion rate of the back electromotive force is 10.1%.

[0042] Comparative Example 2:

[0043] g2 / g1 is 1.5, in which case the waveform distortion rate of the back electromotive force is 8.4%.

[0044] Comparative Example 3:

[0045] g2 / g1 is 2, at this time the waveform distortion rate of back electromotive force is 6.6%.

[0046] Example 1:

[0047] g2 / g1 is 2.5, at this time the waveform distortion rate of back electromotive force is 4.9%.

[0048] Example 2:

[0049] g2 / g1 is 3, at this time the waveform distortion rate of back electromotive force is 4.2%.

[0050] Example 3:

[0051] g2 / g1 is 3.5, at this time the waveform distortion rate of back electromotive force is 4.1%.

[0052] According to the above Figure 3 , the above comparative examples and examples can be found that when the ratio of g2 / g1 increases, the waveform distortion rate of back electromotive force gradually decreases, when g2 / g1 is 2.5, the waveform distortion rate decreases to 3.9%, that is, at this time the harmonic peak value in the back electromotive force is low, and the interference to the fundamental wave is small, so the waveform distortion rate of back electromotive force is reduced. In order to avoid the waveform distortion rate of back electromotive force being too high, the waveform distortion rate of back electromotive force should be controlled within 5% in general, at the same time, the structural strength of the rotor 10 is avoided to be too low, which leads to the service life of the motor to be reduced, so the preferred value of g2 / g1 in the embodiment is between 2.5 and 3.5.

[0053] Further, two thinning portions 13 are arranged between the two adjacent rotor slots 14, and the two thinning portions 13 have an arc surface 15 therebetween, and the central angle B corresponding to the arc surface 15 satisfies the relationship: 19°≤B≤21°.

[0054] Specifically, the magnetic force lines emitted by the permanent magnet 30 in the magnet slot 12 are concentrated on the arc surface 15, and the magnetic force lines at the arc surface 15 are more than those at the thinning portion 13 and the rotor slot 14, while the magnetic force lines at the thinning portion 13 are more than those at the rotor slot 14. At this time, the magnetic density at the air gap 41 outside the periphery of the arc surface 15 is higher than that at the air gap 41 at the thinning portion 13, and the magnetic density at the air gap 41 at the thinning portion 13 is higher than that at the air gap 41 at the rotor slot 14, that is, along the direction of the arc surface 15, the thinning portion 13 and the rotor slot 14, the magnetic density of the air gap 41 decreases in turn, and then along the direction of the rotor slot 14, the thinning portion 13 and the arc surface 15, the magnetic density in the air gap 41 increases in turn, so that the magnetic density in the air gap 41 conforms to the sinusoidal distribution. At the same time, it can be understood that the magnetic density in the air gap 41 corresponding to the arc surface 15 is the maximum value, if the central angle B of the arc surface 15 is larger, such as B is greater than 21°, at this time the arc surface 15 is larger, the magnetic density in the air gap 41 corresponding to the arc surface 15 is almost the same, so that the waveform diagram of the back electromotive force tends to be trapezoidal wave. When B is less than 19°, at this time the arc surface 15 is smaller, finally the magnetic density distribution of the whole air gap 41 does not conform to the sinusoidal distribution, finally leading to the existence of higher waveform distortion rate of the back electromotive force. The value of B can be 19°, 19.5°, 20°, 20.5° and 21°. In this embodiment, in fact, the thinning portion 13 is a slope connected between the arc surface 15 and the rotor slot 14, and along the circumferential direction of the arc surface 15 to the rotor slot 14, the thickness of the rotor 10 at the slope gradually decreases. The setting of the slope makes the magnetic density in the air gap 41 corresponding to the slope gradually decrease along the direction of the arc surface 15 to the rotor slot 14, so that the change of the magnetic density in the air gap 41 is more uniform.

[0055] Further, the rotor slot 14 extends to the outer circumferential surface of the rotor 10, and the circumferential angle C of the arc length corresponding to the two opposite side walls of the rotor slot 14 across the outer circumferential surface of the rotor 10 satisfies the relationship: 14°≤C≤16°.

[0056] Specifically, the rotor slot 14 should not be too large, that is, when D is greater than 16°, at this time the rotor slot 14 is set larger, which will lead to the decrease of the structural strength of the rotor 10, and further decrease the service life of the motor. Since the magnetic field strength in the air gap 41 at the rotor slot 14 is smaller, the peak value of the back electromotive force on the stator 20 is at the lowest point in part of the time, finally making the falling section of the back electromotive force waveform be a trapezoidal wave. If D is less than 14°, the rotor slot 14 is set smaller, which will make the magnetic density in the air gap 41 corresponding to the rotor slot 14 decrease less, so as to make the magnetic density in the whole air gap 41 not present sinusoidal distribution. The value of D can be 14°, 14.5°, 15°, 15.5° and 16°.

[0057] Further, the minimum distance H between the magnet slot 12 and the rotor slot 14 satisfies the relationship: 0.4mm≤H≤0.7mm.

[0058] As mentioned above, if the minimum distance H between the magnet slot 12 and the rotor slot 14 is too large, i.e. H is greater than 0.7mm, the magnetic lines of force on the permanent magnet 30 are more likely to pass through the magnetic bridge formed between the magnet slot 12 and the rotor slot 14 to enter the adjacent other pole, resulting in more magnetic leakage. If H is less than 0.4mm, it is not convenient for processing, and too small H will result in a decrease in the structural strength of the rotor 10. In theory, H is 0 is the best, so as to minimize the rotor magnetic leakage, but limited to the embodiment that the rotor 10 is integrally formed, if H is 0, the area of the first through hole 11 and the magnet slot 12 connected thereto will be separately provided with the rotor 10, and can only be connected by injection molding the rotor 10, the permanent magnet 30 and the above-mentioned area.

[0059] Further, the stator 20 comprises a plurality of stator teeth 21, which are arranged at intervals on the side of the stator 20 close to the rotor 10, and a plurality of tooth slots 211 are arranged at intervals along the circumferential direction of the stator 20 on the side of the stator teeth 21 close to the outer periphery of the rotor 10.

[0060] Specifically, the size of the air gap 41 between the rotor 10 and the stator 20 can affect the peak value of the back electromotive force on the stator 20, i.e. the larger the air gap 41 between the rotor 10 and the stator 20, the smaller the peak value of the back electromotive force; and the smaller the air gap 41 between the rotor 10 and the stator 20, the larger the peak value of the back electromotive force. In order to make the waveform graph of the back electromotive force tend to be a sine wave, tooth slots 211 are arranged at intervals on the stator teeth 21, that is, when the motor starts, the distance between the arc-shaped section and the stator slot 22 is the smallest, and the magnetic density in the air gap 41 around the arc-shaped section is the largest, so the back electromotive force generated by the magnetic field at the arc-shaped section on the stator 20 is the largest, corresponding to the highest point in the sine wave. After the tooth slots 211 are arranged on the stator teeth 21, the air gap 41 at the tooth slots 211 is increased, thereby reducing the magnetic density in the air gap 41, and the peak value of the back electromotive force generated by the magnetic field at the tooth slots 211 on the stator 20 is lower than that at the arc-shaped section, so that the waveform graph is closer to a sine wave.

[0061] Furthermore, two slots 211 are provided on the side of the stator tooth 21 near the outer periphery of the rotor 10, spaced circumferentially along the stator 20. The two slots 211 on the same stator tooth 21 are symmetrically arranged along the midpoint of the stator tooth 21. In a cross-section obtained by cutting the stator 20 along a direction perpendicular to the axis of the stator 20, the line connecting the midpoint of one slot 211 on the same stator tooth 21 to the center of the stator 20 is a first straight line, and the line connecting the midpoint of the other slot 211 to the center of the stator 20 is a second straight line. The angle A between the first and second straight lines satisfies the relationship: 9° ≤ A ≤ 11°. The midpoint of the stator tooth 21 is shown in the attached figure. Figure 1 As shown by the straight line m3.

[0062] As attached Figure 4 As shown in the figure, this embodiment presents back electromotive force (EMF) waveforms for two types of motors. Curve m1 represents the back EMF waveform of a motor without slots 211 on the stator tooth 21, while curve m2 represents the back EMF waveform of a motor with two slots 211 spaced circumferentially along the stator 20 on one side of the stator tooth 21, and the two slots 211 on the same stator tooth 21 are symmetrically arranged along the midline of the stator tooth 21. Clearly, at the peak of the waveform, because there are two slots 211 on one stator tooth 21, the waveform at that point has an arc-shaped transition, while the waveform of the motor without slots 211 on the stator tooth 21 has a straight transition at the peak. On the other hand, the spacing between two adjacent slots 211 on the same stator tooth 21 should not be set too large. If it is set too large, i.e., A is greater than 11°, it will cause a dip in the rising region of some waveforms in the waveform diagram, resulting in unstable torque output of the motor. If the spacing between the two slots 211 is set too small, i.e., A is less than 9°, it will cause a dip at the peak of the waveform diagram, reducing the peak value of the back electromotive force and thus affecting the overall performance of the motor. The value of A can be 9°, 9.2°, 9.4°, 9.6°, 9.8°, 10°, 10.2°, 10.4°, 10.6°, 10.8°, and 11°.

[0063] Furthermore, the maximum depth of the tooth groove 211 is g3, and the minimum distance between the outer peripheral surface of the rotor 10 and the inner wall surface of the second through hole 40 is g1. Among them, g3 and g1 satisfy the relationship: 0.9≤g1 / g3≤1.1.

[0064] It can be understood that if the maximum depth of the tooth slot 211 is too large, for example, g1 / g3 is less than 0.9, the magnetic density in the air gap 41 corresponding to the tooth slot 211 is too low, thereby causing the concave condition of part of the waveform in the waveform diagram, so that the torque output of the motor is unstable, the motor vibrates greatly, and the noise is large. If the maximum depth of the tooth slot 211 is too low, the back electromotive force is excessively linear at the wave peak, that is, the waveform diagram is in a trapezoidal arrangement, thereby making the motor prone to pulse when rotating, so that the motor runs unstably, and the output efficiency of the motor is reduced. The value of g1 / g3 can be 0.9, 0.95, 1, 1.05, and 1.

[0065] In addition, the stator 20 of the present application includes 12 stator slots 22 arranged between adjacent two stators, and a plurality of stator slots 22 are arranged in the axial direction. In the present embodiment, the number of stator slots 22 is 12, and the number of permanent magnets is 8, that is, the motor of the present embodiment is a 12-slot 8-pole motor. The included angle of the extension length between adjacent two magnet slots 12 is 45°, so as to adapt to the value range of the parameters g2 / g1, H, A, B, C and D of the motor. The motor of the present application is a concentrated winding type motor. In addition, the rotor 10 is also provided with a plurality of balance block mounting holes 50 arranged in the circumferential direction of the rotor 10. The dynamic balance of the rotor 10 and the compressor pump body is adjusted by the balance block, so as to reduce the vibration and noise of the compressor.

[0066] In summary, in the motor of the application, two magnet grooves 12 are respectively communicated with a first through hole 11 along the circumferential direction of the rotor 10, and the two magnet grooves 12 communicated with the same first through hole 11 are symmetrically arranged along the center line of the first through hole 11, and the two magnet grooves 12 extend along the radial direction, thereby changing the distribution of magnetic density in the air gap 41, making the magnetic density distribution of the air gap 41 along the axial direction tend to be sinusoidal, thereby reducing the size of the harmonic of the back electromotive force, and finally improving the stability of the motor. In addition, the outer periphery of the rotor 10 is provided with a thinning portion 13 and a rotor groove 14, and the thinning portion 13 and the rotor groove 14 can reduce the magnetic density in the air gap 41 at this position, thereby making the size of the air gap 41 along the circumferential direction decrease first and then increase and cycle in turn, that is, making the magnetic density distribution in the air gap 41 more tend to be sinusoidal. On the other hand, the first through hole 11 and the rotor groove 14 of the application are arranged on both sides of the magnet groove 12, the magnet groove 12 extends along the radial direction, the first through hole 11 can isolate the magnetic force line from passing through the rotor 10 along the direction close to the axis, and the relative position of the rotor groove 14 and the magnet groove 12 is arranged to reduce the thickness H of the magnetic bridge between the rotor groove 14 and the magnet groove 12, thereby reducing the magnetic leakage of the motor. On the other hand, the application also opens a tooth groove 211 on the stator tooth 21, and two symmetrical tooth grooves 211 are opened on one stator tooth 21, so that the magnetic density in the air gap 41 at the tooth groove 211 decreases, thereby making the magnetic density in the air gap 41 conform to the sinusoidal distribution, and finally reducing the waveform distortion rate of the back electromotive force.

[0067] For the convenience of description, spatial relative terms such as "above", "upper", "on", "top", etc. can be used herein to describe the spatial positional relationship of one device or feature with other devices or features as shown in the drawings. It should be understood that the spatial relative terms are intended to include different orientations in use or operation in addition to the orientation of the device described in the drawings. For example, if the device in the drawing is inverted, the device described as "above" or "on" other devices or structures will be positioned "below" or "under" other devices or structures. Therefore, the exemplary term "above" can include both "above" and "below" orientations. The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein are interpreted accordingly.

[0068] In addition, it should be noted that the use of "first", "second", and the like to define parts is only for the convenience of distinguishing the corresponding parts, and the above terms have no special meaning unless otherwise stated, and therefore cannot be understood as limiting the scope of protection of the application.

[0069] The above merely provides 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. An electric machine characterized in that, The rotor (10) is provided with a plurality of first through holes (11) and a plurality of magnet grooves (12) which are arranged at intervals in the circumferential direction of the rotor (10), the first through holes (11) and the magnet grooves (12) are both provided in the axial direction of the rotor (10), the first through holes (11) extend in the circumferential direction of the rotor (10) by a predetermined length, the magnet grooves (12) are arranged on the side of the first through holes (11) close to the outer circumferential surface of the rotor (10) and communicate with the first through holes (11), each of the magnet grooves (12) extends in the radial direction of the rotor (10), and one first through hole (11) is respectively communicated with one magnet groove (12) at both ends in the circumferential direction of the rotor (10), and the two magnet grooves (12) communicated with the same first through hole (11) are symmetrically arranged about the center line of the first through hole (11). The permanent magnets (30) include a plurality of permanent magnets (30), and each of the plurality of permanent magnets (30) is embedded in one of the plurality of magnet grooves (12) in a one-to-one correspondence. The stator (20) is provided with a second through hole (40), and the stator (20) is sleeved on the outer circumference of the rotor (10) through the second through hole (40). The outer circumferential side of the rotor (10) is provided with a plurality of thinning portions (13) and a plurality of rotor grooves (14) arranged at intervals, and the rotor grooves (14) are arranged in a one-to-one correspondence with the magnet grooves (12).

2. The electric machine of claim 1, wherein, The rotor groove (14) is provided with the thinning portion (13) on both sides in the circumferential direction of the rotor (10), and the minimum distance from the rotor groove (14) to the axis of the rotor (10) is smaller than the minimum distance from the thinning portion (13) to the axis of the rotor (10). The minimum distance g1 between the outer circumferential surface of the rotor (10) and the inner wall surface of the second through hole (40) and the maximum distance g2 between the rotor groove (14) and the inner wall surface of the second through hole (40) satisfy the relationship 2.5≤g2 / g1≤3.5; wherein 0.45mm≤g1≤0.55mm.

3. The electric machine of claim 2, wherein, Two thinning portions (13) are arranged at intervals between adjacent two rotor grooves (14), and an arc surface (15) is arranged between the two thinning portions (13), and the corresponding central angle B of the arc surface (15) satisfies the relationship 19°≤B≤21°.

4. The electric machine of claim 2, wherein, The rotor groove (14) extends to the outer circumferential surface of the rotor (10), and the central angle C of the corresponding arc length of the two opposite side walls of the rotor groove (14) across the outer circumferential surface of the rotor (10) satisfies the relationship 14°≤C≤16°.

5. The electric machine of claim 2, wherein, The minimum distance H between the magnet groove (12) and the rotor groove (14) satisfies the relationship 0.4mm≤H≤0.7mm.

6. The electric machine of any one of claims 2 to 5, characterized by ​ 7. The electric machine of any one of claims 1 to 5, wherein, The stator (20) comprises a plurality of stator teeth (21) which are arranged at intervals on the side of the stator (20) close to the rotor (10), and the stator teeth (21) are provided with a plurality of tooth grooves (211) which are arranged at intervals along the circumferential direction of the stator (20) on the side close to the outer periphery of the rotor (10).

8. The electric machine of claim 7, wherein, The stator teeth (21) comprise 12 stator teeth (21), and one stator slot (22) is arranged between adjacent two stator teeth (21), and the permanent magnet comprises 8 permanent magnets.

9. The electric machine of claim 7, wherein, The stator teeth (21) are provided with two tooth grooves (211) which are arranged at intervals along the circumferential direction of the stator (20) on the side close to the outer periphery of the rotor (10), and the two tooth grooves (211) on the same stator tooth (21) are symmetrically arranged along the center line of the stator tooth (21). In the cross section of the stator (20) obtained by cutting along the axial direction of the stator (20) and the direction perpendicular to the axial direction of the stator (20), the connecting line from the midpoint of one tooth groove (211) on the same stator tooth (21) to the center of the stator (20) is a first straight line, and the connecting line from the midpoint of the other tooth groove (211) to the center of the stator (20) is a second straight line, and the included angle A between the first straight line and the second straight line satisfies the relationship: 9°≤A≤11°.

10. The electric machine of claim 7, wherein, The maximum depth of the tooth groove (211) is g3, and the minimum distance between the outer periphery of the rotor (10) and the inner wall surface of the second through hole (40) is g1, wherein the relationship between g3 and g1 satisfies the relationship: 0.9≤g1 / g3≤1.

1.

11. A compressor characterized by, The compressor comprises the motor according to any one of claims 1 to 10.

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