Stator, permanent magnet motor and compressor

Abstract

The utility model provides a stator, a permanent magnet motor and a compressor, the stator comprises a stator yoke and convex teeth, and the stator yoke is of an annular structure and comprises a first arc-shaped part arranged on the inner side and a second arc-shaped part arranged on the outer side; the plurality of convex teeth are uniformly arranged at intervals along the inner side of the stator yoke, and a stator slot is formed between every two adjacent convex teeth; the convex teeth and the first arc-shaped part are connected at an intersection point A, and the intersection point A is located on a circle phi D1 with the circle center being O and the diameter being D1; in the circumferential direction of the circle phi D1, the convex teeth form an arc length Wa between the two intersection points A; in the radial direction of the circle phi D1, the convex teeth have a symmetry axis Y passing through the circle point O, and an included angle Ta is formed between the line segment OA and the symmetry axis Y; d1, Wa and Ta have the relational expression that Wa is larger than or equal to 2 * D1 * Sin (Ta / 2) and smaller than or equal to 7.8 mm. Through the limitation of the stator core, when the motor runs at a high speed, the low-order armature magnetic potential harmonic waves on the stator winding are effectively suppressed, and the harmonic wave loss is reduced.

Description

TECHNICAL FIELD

[0001] The utility model belongs to compressor technical field, concretely relates to a kind of stator, permanent magnet motor and compressor. BACKGROUND

[0002] Air compressor, as the core component of temperature control equipment, whether its performance is superior mainly depends on compression pump and motor of driving pump.And motor applied to compressor, because its working condition is obviously different from other motors, therefore, relevant design also has difference.

[0003] And in the permanent magnet motor used in compressor, its stator core is often made of symmetrical stator tooth structure to avoid introducing larger harmonic magnetic field, reduce the condition of electric energy loss caused by harmonic magnetic field.At the same time, the stator tooth of symmetrical structure is more convenient for design, processing and assembly.

[0004] However, at high speed, permanent magnet motor cannot avoid the problems of increased vibration noise and improved harmonic loss.Long-term vibration noise increase is easy to cause the abrasion of equipment mechanical structure and the discomfort of personnel, and harmonic loss reduces the performance of motor, so that the power of compressor is limited.How to reduce the performance loss of motor and reduce noise output under the premise of high speed becomes the most intractable problem at present. SUMMARY

[0005] In order to solve the prior art problems, the utility model provides a kind of stator, by setting intersection A and leading out circle φD1, arc length Wa and included angle Ta are limited, realize the purpose of reducing the performance loss and working noise generated by motor at high speed.

[0006] The technical effects achieved by the utility model are realized by the following technical aspects:

[0007] Firstly, the utility model provides a kind of stator, including stator core, the stator core includes:

[0008] Stator yoke, annular structure, including the first arc-shaped part of inside and the second arc-shaped part of outside;

[0009] Convex tooth, a plurality of convex teeth are uniformly arranged along the inside of the stator yoke, and stator slot is formed between adjacent two convex teeth;

[0010] The convex tooth and the first arc-shaped part meet at intersection A, and the intersection A is located on circle φD1 with center O and diameter D1;

[0011] On the circumference of circle φD1, the convex tooth forms arc length Wa between two intersections A;

[0012] In the radial direction of the circle φD1, the convex teeth have an axis of symmetry Y passing through the circle point O, and the angle Ta is formed between the line segment OA and the axis of symmetry Y; D1, Wa and Ta have the following relationship:

[0013] 2*D1*Sin(Ta / 2)≤Wa≤7.8mm.

[0014] In some implementations, the second arc-shaped part is partially coincident with a circle φD2 with a center O and a diameter D2, the diameter D2 is the maximum outer diameter of the stator yoke, and D1 and D2 have the following relationship:

[0015] D1<D2-5mm.

[0016] In some implementations, in adjacent convex teeth, the axis of symmetry Y of one convex tooth forms an angle Tb with the line segment OA of the adjacent other convex tooth, wherein,

[0017] The range of Ta is 2°<Ta<15°, and the range of Tb is 17°<Tb<30°.

[0018] In some implementations, the number of the convex teeth is N, and N is 12 or 15.

[0019] In the second aspect, the utility model provides a kind of permanent magnet motor, including rotor and above-mentioned stator;

[0020] The convex teeth are provided with a boot portion, and a plurality of boot portions surround a cavity for accommodating a rotor, and the rotor is rotatably arranged in the cavity.

[0021] In some implementations, the stator has a shaft core X, and the centers O of the circle φD1 and the circle φD2 are located on the shaft core X.

[0022] In some implementations, the rotor outer ring has a gap with the boot portion, and the distance of the gap is G, and the range of G is 0.45mm≤G<2.2mm.

[0023] In some implementations, further comprising a magnet, a plurality of magnet holes are provided in the rotor, the magnet holes are in the shape of a "V" and have openings facing the stator, the magnet holes are uniformly arranged along the circumference of the rotor, the magnet is arranged in the magnet hole, and the opening side angle of the magnet hole is Bt, in adjacent convex teeth, the axis of symmetry Y of one convex tooth forms an angle Tb with the line segment OA of the adjacent other convex tooth, and the condition Bt≥Tb is met.

[0024] In some implementations, a plurality of magnetic flux grooves are symmetrically arranged at the end of the opening of the magnet hole.

[0025] In a third aspect, the utility model provides a kind of compressor, including shell, compression pump, drive shaft and above-mentioned permanent magnet machine, the compression pump is set in the bottom in shell, the permanent magnet machine is fixedly set in the middle in shell, the rotor is driven the compression pump rotation by the drive shaft.

[0026] Summarized above, the utility model at least has following beneficial effects:

[0027] 1, the utility model provides a stator, by setting the intersection A of convex tooth and first arc portion, and with the circle phi D1 related to convex tooth is led out with intersection A, again with this setting arc length Wa, angle Ta and diameter D1 Three parameters, using three parameters to limit relation 2*D1*Sin (Ta / 2)≤Wa≤7.8mm. So that motor in high-speed operation process, the low-order armature magnetic potential harmonic generated on stator winding is effectively inhibited, and harmonic loss is reduced.

[0028] 2, the utility model provides a stator, only quote and limit three parameters can obtain effective inhibition low-order armature magnetic potential harmonic effect under high-speed state, when designing stator core, it is convenient for designer to determine each working condition, calculate and analyze the shape and parameter of optimal stator core.

[0029] 3, the utility model provides a permanent magnet machine, after using above-mentioned stator, the energy efficiency ratio under high-speed working state is further promoted, and the noise of motor high-frequency operation is also improved, optimized. So that more optimal hearing effect is obtained, and the service life of motor is also longer. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 It is the cross section view of the stator of the utility model embodiment 1.

[0031] Figure 2 It is Figure 1 The enlarged view of the middle E.

[0032] Figure 3 It is the schematic diagram of each parameter of the stator core of the utility model embodiment 1.

[0033] Figure 4 It is the motor counter electromotive force waveform diagram of the stator of embodiment 1 and prior art stator scheme.

[0034] Figure 5 It is the internal cross section view of the permanent magnet machine of the utility model embodiment 2.

[0035] Figure 6 It is Figure 5 The enlarged view of the middle F.

[0036] Figure 7The tooth slot torque curve diagram of the permanent magnet motor of the embodiment 2 of the utility model and the prior art motor of the same kind.

[0037] Figure 8 The compressor cut view of the embodiment 3 of the utility model.

[0038] Figure 9 The noise spectrum diagram of the compressor of the embodiment 3 of the utility model and the prior art compressor in the same air conditioner body.

[0039] Markings in the figure:

[0040] 10, stator;

[0041] 1, stator core, 11, stator yoke, 111, first arc-shaped part, 112, second arc-shaped part, 12, convex tooth, 121, boot part, 13, stator slot, 14, cavity;

[0042] 2, stator winding;

[0043] 100, permanent magnet motor;

[0044] 20, rotor, 201, magnet, 202, magnet hole, 203, magnetic flux slot hole;

[0045] 30, gap;

[0046] 200, compressor, 2001, shell, 2002, compression pump, 20021, driving shaft;

[0047] A-intersection A; O-center O; Y-symmetry axis Y; X-axis core X. DETAILED DESCRIPTION

[0048] In order to make the purpose, technical scheme and advantages of the embodiments of the utility model clearer, the technical scheme in the embodiments of the utility model will be described clearly and completely in combination with the drawings in the embodiments of the utility model below. The described embodiments are part of the embodiments of the utility model, rather than all the embodiments.

[0049] Therefore, the following detailed description of the embodiments of the utility model provided in the drawings is not intended to limit the scope of the claimed utility model, but only represents selected embodiments of the utility model. Based on the embodiments in the utility model, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the utility model.

[0050] In addition, it should be noted that, in order to facilitate understanding and simplify the description, the length units expressed below are all mm.

[0051] Embodiment 1:

[0052] Please refer to Figures 1-4 The embodiment provides a stator 10, comprising a stator core 1 and a stator winding 2. The stator core 1 comprises a stator yoke 11 and a salient tooth 12. The stator yoke 11 has a ring structure, comprising a first arc-shaped part 111 arranged on the inner side and a second arc-shaped part 112 arranged on the outer side. A plurality of salient teeth 12 are arranged on the inner side of the stator yoke 11 in a spaced and uniform manner, and a stator slot 13 is formed between adjacent two salient teeth 12. The stator slot 13 is used to accommodate the stator winding 2. In actual production, the salient tooth 12 and the first arc-shaped part 111 are integrally formed to form the stator core 1. As shown in the figure, the intersection between the salient tooth 12 and the first arc-shaped part 111 is the intersection point A. It can be seen that the intersection point A is related to the two features of the stator yoke 11 and the salient tooth 12, that is, the parameters related to the intersection point A have certain limiting effect on the stator yoke 11 and the salient tooth 12. Figure 2

[0053] It should be noted that in actual production and application, in order to reduce the stress concentration problem during forming, a fillet is arranged on both sides of the joint between the first arc-shaped part 111 and the salient tooth 12. In this embodiment, the intersection point A is the intersection of the fillet and the edge of the salient tooth 12.

[0054] As shown in the figure, all the intersection points A on the stator core 1 are associated, and all the intersection points A fall on a circle φD1 with a center O and a diameter D1. Generally, the center O is the center of symmetry of the stator yoke 11 and the salient tooth 12. In the circumferential direction of the circle φD1, the salient tooth 12 forms an arc length Wa between two intersection points A. In the radial direction of the circle φD1, the salient tooth 12 has a symmetry axis Y passing through the circle point O, and an included angle Ta is formed between the line segment OA and the symmetry axis Y. Figure 3

[0055] When the relationship between D1, Wa and Ta satisfies the relationship formula: 2*D1*Sin(Ta / 2)≤Wa≤7.8, the low-order armature magnetic potential harmonics on the stator winding 2 are obviously suppressed.

[0056] In order to facilitate description, we select the experimental results of two groups of parameters for description, and the two groups of parameters are: the first group (reference group), D1=80.1, Wa=5.8826 and Ta=4.21°; the second group (experimental group), D1=75.02, Wa=4.80286 and Ta=3.67°, and the second group of data satisfies the above relationship formula. After the test, the back electromotive force waveform diagram is obtained as shown in the figure. Figure 4

[0057] The distortion in the back electromotive force waveform is mainly caused by the low-order armature magnetic potential harmonics generated by the stator 10. In the Figure 4 ​​​In the figure, curve 1 is the curve result of the first group of tests, and curve 2 is the curve result of the second group of tests. Obviously, compared with the first group, the waveform distortion rate of the counter electromotive voltage curve of the second group is obviously reduced, which indicates that the influence of the low-order armature magnetic potential harmonics generated by the stator 10 on the output of the motor is inhibited. That is, by limiting the three parameters D1, Wa and Ta through the above-mentioned limiting formula, the low-order armature magnetic potential harmonics can be effectively inhibited, and the harmonic loss can be reduced. In the experiment, through the measured data, it is calculated that the counter electromotive voltage waveform distortion rate can be reduced by 23%. However, since it is impossible to exhaust all the experimental results of the parameter groups, they are not listed one by one here.

[0058] However, in the high-speed state, only the limitation of the three parameters can reduce the harmonic loss and improve the energy efficiency ratio of the motor. The above formula is more conducive to the rapid limitation or verification of the parameters of the stator core 1 by the designers.

[0059] Continuing to refer to Figures 1-3 The second arc-shaped part 112 is partially overlapped with a circle φD2 with a center O and a diameter D2, and the diameter D2 is the maximum outer diameter of the stator yoke 11. In operation, the transformed magnetic induction lines pass through the area between the circle φD1 and the circle φD2, and the stator yoke 11 is also arranged in the area. The transformed magnetic field generated by the stator winding 2 must pass through the stator yoke 11. In order to further reduce the harmonic loss and at the same time ensure the structural strength of the stator core 1, there is a relationship between D1 and D2: D1 < D2-5.

[0060] In order to ensure that the requirement of reducing the harmonic loss is met in the case of different design powers, in the adjacent protruding teeth 12, the symmetry axis Y of one protruding tooth 12 and the line segment OA of the adjacent another protruding tooth 12 form an included angle Tb, wherein the range of Ta is 2° < Ta < 15°, and the range of Tb is 17° < Tb < 30°. By adjusting the values of Ta and Tb, the geometric parameters of the protruding teeth 12 and the stator slots 13 can be adjusted, so that the number of turns and the number of the stator winding 2 are modified, and the design power of the motor is adjusted.

[0061] In the embodiment, the stator 10 is used in a three-phase motor, and the number of the protruding teeth 12 is N, and N should be an integer multiple of 3. Considering the actual production, cost control and harmonic loss, the value of N is 12 or 15, which is more optimal.

[0062] In summary, the stator provided by the utility model, through setting the intersection A of the protruding teeth and the first arc-shaped part, and leading out the circle φD1 related to the protruding teeth from the intersection A, and then setting the arc length Wa, the included angle Ta and the diameter D1 three parameters, and adopting the three parameters to limit the relationship formula 2*D1*Sin(Ta / 2)≤Wa≤7.8, the low-order armature magnetic potential harmonics generated on the stator winding in the high-speed operation process of the motor is effectively inhibited, and the harmonic loss is reduced.

[0063] In addition, only three parameters are referenced and limited, and the effect of effectively suppressing low-order armature magnetic potential harmonics in high-speed state is obtained. When designing the stator core 1, the designer can calculate and analyze the optimal shape and parameters of the stator core 1 when determining the working conditions.

[0064] Embodiment 2:

[0065] This embodiment provides a permanent magnet motor 100, which includes a rotor 20 and a stator 10 described in Embodiment 2. Please refer to Figures 1-4 , and refer to Figures 5-6 , the convex teeth 12 are provided with a shoe portion 121, and a plurality of shoe portions 121 surround a cavity 14 for accommodating the rotor 20, and the rotor 20 is rotatably arranged in the cavity 14. After the stator 10 of Embodiment 1 is used, the output efficiency of the permanent magnet motor 100 is improved due to the effective suppression of low-order armature magnetic potential harmonics. In the process of high-speed operation of the rotor 20, the noise caused by the influence of low-order armature magnetic potential harmonics will be significantly reduced. For the permanent magnet motor 100 provided in this embodiment, which is arranged in an area where people are active, it has a better hearing effect than the existing similar permanent magnet motor scheme.

[0066] In some embodiments, the stator 10 has an axis core X, and the centers O of the circles φD1 and φD2 are located on the axis core X. The axis core X generally specifies the manufacturing axis core of the stator 10, ensures the central symmetry of the stator core 1 and the stator winding 2 during manufacturing, and ensures the stability of the rotor 20 during operation. When the centers O of the circles φD1 and φD2 are located on the axis core X, the harmonic loss generated during high-speed operation of the rotor 20 is more uniform, and the mutation is smaller, which is beneficial to prolong the service life of the motor circuit part and the bearing.

[0067] The outer ring of the rotor 20 has a gap 30 with the shoe portion 121, and the size of the gap 30 will affect the magnetic field acting between the rotor 20 and the stator 10. If the gap 30 is too large, it will affect the output torque and other mechanical properties of the rotor 20, but if the gap 30 is too small, it will increase the influence of the magnetic field of the rotor 20 on the stator 10. In this embodiment, the distance of the gap 30 is G, and G is in the range of 0.45≤G<2.2. When G is in the range, the output torque and harmonic loss of the permanent magnet motor 100 are controlled in an optimal range.

[0068] Of course, the permanent magnet motor 100 of this embodiment also includes a magnet 201, such as Figure 6As shown, the rotor 20 is provided with a plurality of magnet holes 202, the magnet holes 202 are in the shape of "V" and the opening is towards the stator 10. The magnet holes 202 are evenly arranged along the circumferential direction of the rotor 20, and the magnets 201 are arranged in the magnet holes 202. The angle of the opening side of the "V"-shaped magnet hole 202 has a direct impact on the magnetic field generated by the stator winding 2 and the output torque of the rotor 20. If the angle of the opening side of the magnet hole 202 is Bt, then the condition Bt >= Tb is met. If Bt is less than Tb, the composite magnetic field generated by the two magnets 201 will form an unignorable resistance to the magnetic field generated by the two stator windings 2, and significantly increase the low-order armature magnetic potential harmonics of the stator winding 2.

[0069] Of course, in the embodiment, in order to optimize the magnetic flux of the rotor 20, a plurality of magnetic flux grooves 203 are symmetrically arranged at the opening end of the magnet hole 202. The shape and size of the actual magnetic flux groove 203 need to be determined according to the actual design situation.

[0070] Figure 7 In order to detect the tooth slot torque of the stator 10 without power supply, the obtained curve diagram is obtained. The curve 3 is the data obtained by using the permanent magnet motor 100 provided by the embodiment, and the curve 4 is the data obtained by using the permanent magnet motor of the same type scheme. It can be seen that the tooth slot torque value of the permanent magnet motor 100 of the embodiment is smaller than that of the existing scheme, and the fluctuation is gentle. The vibration or noise resonance generated is greatly reduced. In addition to the optimization of the noise and resonance described above, the mechanical life of the motor is also improved due to the reduction of vibration. In the experiment, the tooth slot torque of the test group is reduced by 54% compared with the reference group.

[0071] In summary, the permanent magnet motor provided by the utility model further improves the energy efficiency ratio in the high-speed working state of the stator, and the noise of the motor during high-frequency operation is also improved and optimized. Therefore, a better hearing effect is obtained, and the service life of the motor is longer.

[0072] Embodiment 3:

[0073] On the basis of Figures 1-7 , referring to Figures 8-9 , the embodiment provides a compressor 200 used in a temperature control device. The compressor 200 comprises a shell 2001, a driving shaft 20021, a compression pump 2002 and the permanent magnet motor 100 described in embodiment 2. The compression pump 2002 is arranged at the bottom of the shell 2001, and the permanent magnet motor 100 is fixedly arranged in the middle of the shell 2001. The permanent magnet motor 100 drives the compression pump 2002 to rotate through the driving shaft 20021. By arranging the permanent magnet motor 100 of embodiment 2, the noise of the compressor 200 is effectively suppressed.

[0074] In order to better compare the use effect, the compressor 200 of the embodiment and the existing same type compressor are tested, and the two are respectively installed into the same air conditioner body, and the noise spectrum diagram of the two is measured. Figure 9 The spectrum curve diagram is for one of the experimental groups, and curve 5 is the data of the experimental group of the compressor 200 of the embodiment. Obviously, compared with the prior art, the overall noise of the compressor 200 of the embodiment converges, the noise is reduced by 2dB, and the low-order frequency peak is reduced by 21%, and the hearing effect is better.

[0075] The reduction of noise also reduces the mechanical vibration, thereby improving the service life of the compressor 200 as a whole. In addition, since the vibration of the permanent magnet motor 100 is suppressed, the failure rate of the compressor 200 is also greatly reduced under the same performance.

[0076] In the present application, unless otherwise clearly specified and limited, the terms "mounting", "connecting", "connecting", "fixing" and the like should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication between two elements or the interaction relationship between two elements. For ordinary skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0077] In the description of the present application, it should be pointed out that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, or the orientation or positional relationship commonly used when the product of the present application is used, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, therefore it cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third" and the like are only used for differentiation, and cannot be understood as indicating or implying relative importance.

[0078] In addition, the terms "horizontal", "vertical", "suspension" and the like do not mean that the parts must be absolutely horizontal or suspended, but can be slightly inclined. For example, "horizontal" only means that its direction is relatively more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly inclined.

[0079] In the utility model, unless another definite provision and limitation, first feature is above or below second feature can include that first and second features are in direct contact, also can include that first and second features are not in direct contact but contact through additional feature between them.

[0080] Although the description of the utility model is combined with above specific embodiment, it is obvious that many substitutions, modifications and changes can be made according to the above-mentioned content by the person skilled in the art. Therefore, all such substitutions, improvements and changes are included in the spirit and scope of the appended claims.

Claims

1. A stator comprising a stator core (1), characterized in that The stator core (1) comprises: a stator yoke (11) in a ring structure, comprising a first arc-shaped portion (111) arranged at an inner side and a second arc-shaped portion (112) arranged at an outer side; a plurality of teeth (12) arranged at intervals and uniformly along the inner side of the stator yoke (11), and a stator slot (13) formed between two adjacent teeth (12); the tooth (12) and the first arc-shaped portion (111) meet at an intersection point A, and the intersection point A is located on a circle φD1 with a center O and a diameter D1; in the circumferential direction of the circle φD1, the tooth (12) forms an arc length Wa between two intersection points A; in the radial direction of the circle φD1, the tooth (12) has a symmetry axis Y passing through the circle point O, and an included angle Ta is formed between the line segment OA and the symmetry axis Y; there is a relationship between D1, Wa and Ta: 2*D1*Sin(Ta / 2)≤Wa≤7.8mm.

2. The stator of claim 1, wherein the second arc-shaped portion (112) partially coincides with a circle φD2 with a center O and a diameter D2, the diameter D2 is the maximum outer diameter of the stator yoke (11), and there is a relationship between D1 and D2: D1<D2-5mm.

3. The stator of claim 1, wherein in the adjacent teeth (12), the symmetry axis Y of one tooth (12) and the line segment OA of the adjacent tooth (12) form an included angle Tb, wherein the range of Ta is: 2°<Ta<15°, and the range of Tb is: 17°<Tb<30°.

4. The stator of claim 1, wherein the number of teeth (12) is N, and N is 12 or 15.

5. A permanent magnet electric machine characterized by, comprising a rotor (20) and a stator (10) according to any one of claims 1-4; the end of the tooth (12) is provided with a shoe portion (121), and a plurality of shoe portions (121) surround a cavity (14) for accommodating the rotor (20), and the rotor (20) is rotatably arranged in the cavity (14).

6. The permanent magnet electric machine of claim 5, wherein, the stator (10) has an axis core X, and the centers O of the circles φD1 and φD2 are located on the axis core X.

7. The permanent magnet electric machine of claim 5, wherein, the outer circle of the rotor (20) and the shoe portion (121) have a gap (30), and the distance G of the gap (30) is: 0.45mm≤G<2.2mm.

8. The permanent magnet electric machine of claim 7, wherein, further comprising a magnet (201), a plurality of magnet holes (202) are arranged in the rotor (20), the magnet hole (202) is in the shape of "V", and the opening is directed to the stator (10); the magnet hole (202) is uniformly arranged along the circumferential direction of the rotor (20), the magnet (201) is arranged in the magnet hole (202); the opening side angle of the magnet hole (202) is Bt, and in the adjacent teeth (12), the symmetry axis Y of one tooth (12) and the line segment OA of the adjacent tooth (12) form an included angle Tb, which satisfies the condition: Bt≥Tb.

9. The permanent magnet electric machine of claim 8, wherein, a plurality of magnetic flux slot holes (203) are symmetrically arranged at the end of the opening of the magnet hole (202).

10. Compressor, characterized in that The compressor comprises a shell (2001), a compression pump (2002), a drive shaft (20021) and the permanent magnet motor (100) as claimed in claim 9, the compression pump (2002) is arranged at the bottom of the shell (2001), the permanent magnet motor (100) is fixedly arranged at the middle of the shell (2001), and the rotor (20) drives the compression pump (2002) to rotate through the drive shaft (20021).

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