Rotor punching sheet, permanent magnet synchronous motor and compressor

Abstract

The invention provides a rotor punching sheet, a permanent magnet synchronous motor and a compressor, a shaft hole, a permanent magnet groove and a permanent magnet are arranged on the rotor punching sheet, and an outer edge line comprises a plurality of arc sections and a plurality of trimming sections; the arc section comprises a first arc and two second arcs, the circle center of the first arc is in the center of the rotor punching sheet, the second arcs are not concentric with the first arc, and the trimming section is tangent to the second arcs; the center line of the permanent magnet in the radial direction is defined as a d axis, and the center line between adjacent permanent magnets is defined as a q axis; the first circular arc, the two second circular arcs and the trimming section under one pole are symmetrically distributed by taking the d axis as a symmetry axis, the mechanical angle occupied by the permanent magnet is 2theta, the radius R1 of the first circular arc is the radius of the rotor, and the radius of the second circular arc is R2; the central angle of the first arc under one pole is alpha; the maximum vertical distance h between the whole circle with R1 as the radius and the trimming section meets the condition that h is larger than 0 and equal to [1-cos (theta-alpha)]. (R1-R2) is smaller than or equal to 2.3 mm. The back electromotive force waveform sine degree is improved by changing h and alpha, the back electromotive force harmonic distortion rate is reduced, and torque pulsation is weakened so as to reduce vibration noise.

Description

Technical Field

[0001] The present invention relates to the technical field of compressor design and manufacturing, and in particular to a rotor punching sheet, a permanent magnet synchronous motor and a compressor. Background Art

[0002] In recent years, with the continuous improvement of air-conditioning energy efficiency requirements, variable frequency compressors have the advantages of high efficiency, reliable operation, and small size, and their market share has increased year by year. Permanent magnet synchronous motors have gradually replaced traditional asynchronous motors due to their high efficiency, wide speed regulation range, high power density, and strong overload capacity, and have become the first choice for variable frequency compressor drive motors. However, the back EMF of permanent magnet synchronous motors has poor sinusoidality and contains a large number of harmonics, which increases the torque pulsation of the motor, resulting in high vibration and noise in the entire compressor system, affecting customer comfort. Therefore, effective means are needed to weaken the back EMF harmonics. Usually, measures such as stator skew slots, rotor skew poles, and combined magnetic poles are used to improve the back EMF waveform and suppress torque pulsation, but these measures will bring about problems such as a significant reduction in output torque and difficulty in process implementation. Summary of the invention

[0003] In response to the technical problems raised above, a rotor punching sheet, a permanent magnet synchronous motor and a compressor are provided, aiming to improve the sinusoidality of the motor back-electromotive force waveform and thereby suppress torque pulsation.

[0004] The technical means adopted by the present invention are as follows:

[0005] A rotor punching sheet comprises a punching sheet body, wherein an axial hole concentric with the rotor rotation center is provided in the middle of the punching sheet body, a plurality of permanent magnet slots evenly distributed in the circumferential direction are provided on the punching sheet body, and p N-pole permanent magnets and p S-pole permanent magnets are alternately inserted in the permanent magnet slots;

[0006] The outer edge line of the punch body is a closed line formed by alternately arranging a plurality of arc segments and a plurality of trimming segments, the plurality of arc segments and the plurality of trimming segments are evenly distributed along the circumferential direction, and the trimming segments are straight line segments;

[0007] The arc segment includes a first arc and two second arcs, the center of the first arc is at the center of the rotor punching sheet, the second arc is not concentric with the first arc, the two second arcs are symmetrically distributed about the center line of the first arc in the radial direction, and the two ends of the trimming segment are tangent to the second arcs on both sides respectively;

[0008] The center line of each permanent magnet in the radial direction is defined as the d-axis, which is the center line of the first arc in the radial direction, and the center line between two adjacent permanent magnets is defined as the q-axis;

[0009] Each of the trimming sections is symmetrically arranged along the q axis;

[0010] The first circular arc, two second circular arcs and half of the trimming segments on both sides under one pole are symmetrically distributed with the d axis as the symmetry axis, and the first circular arc, second circular arc and trimming segment corresponding to each pole are evenly distributed along the circumferential direction;

[0011] The mechanical angle occupied by the permanent magnet is 2θ, that is, the angle between the adjacent d-axis and q-axis is θ, and the radius R of the first arc is defined as 1 is the rotor radius, and the radius of the second arc is R 2 ; The central angle of the first arc under a pole is α; R 1 The maximum vertical distance from the cutting edge segment to the full circle with a radius of h satisfies the following relationship: 0<h=[1-cos(θ-α)]·(R 1 -R 2 )≤2.3mm.

[0012] Furthermore, the radius R 1 The value range is: 43.5mm≤R 1 ≤55mm.

[0013] Furthermore, the included angle θ=360° / 2p / 2, and the center angle α of the first arc satisfies 0°<α≤13°.

[0014] Furthermore, the number of N poles and S poles of the permanent magnet is equal, p=3 or p=4.

[0015] Furthermore, a magnetic isolation bridge is formed between the permanent magnet slot and the trimming section, and the thickness w of the magnetic isolation bridge is b Meet 0.6mm≤w b ≤1.2mm;

[0016] There is a magnetic rib between two adjacent permanent magnet slots, and the width of the magnetic rib is the vertical distance w between the adjacent permanent magnet slots. r , and 0.8mm≤w r ≤4.5mm.

[0017] Furthermore, the width of the permanent magnet is h m , thickness is b m , and 8.15≤h m / b m ≤16;

[0018] The residual magnetic induction intensity of the permanent magnet is B r , and 12.2kGs≤B r ≤15.3kGs.

[0019] Furthermore, the permanent magnet is in the shape of an I, and the direction of the magnetic field is parallel to the d-axis.

[0020] Furthermore, a plurality of weight-reducing and heat-dissipating holes and a plurality of rivet holes are evenly arranged on the periphery of the shaft hole.

[0021] The present invention also provides a permanent magnet synchronous motor, comprising the rotor punching sheet as described above.

[0022] The present invention also provides a compressor, which adopts the permanent magnet synchronous motor as described above.

[0023] Compared with the prior art, the present invention has the following advantages:

[0024] 1. The first arc, the second arc and the trimming section between the d-axis and the q-axis of the present invention make the air gap of the motor non-uniformly distributed, which can improve the air gap magnetic flux waveform and thus improve the sinusoidality of the back electromotive force waveform to reduce the harmonic distortion rate of the back electromotive force.

[0025] 2. The present invention changes the 1 The center of the second arc and the radius of the second arc R can be changed by the maximum vertical distance h from the cutting edge segment of the full circle with a radius of 2 , the center angle occupied by the second arc, and the center angle occupied by the cutting edge segment, so that the back electromotive force waveform is improved to varying degrees.

[0026] 3. The output torque of the present invention has a small loss in average value and a high torque density.

[0027] 4. The present invention can significantly reduce the cogging torque by selecting appropriate h and α.

[0028] 5. The output torque of the present invention is of high quality, and the torque pulsation is significantly reduced compared with the conventional solution, which can reduce the electromagnetic vibration noise during the operation of the compressor.

[0029] 6. The present invention can conveniently match the moment of inertia by dynamically adjusting the size of the weight-reducing heat dissipation holes, and cooperate with the inverter to obtain better dynamic and steady-state characteristics. In addition, the refrigerant circulation area can be increased to reduce the temperature rise of the motor body and increase the efficiency of the system.

[0030] Based on the above reasons, the present invention can be widely promoted in the fields of motors, compressors, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0032] Figure 1 It is a schematic structural diagram of the rotor punching of the present invention.

[0033] Figure 2 The following is a comparison waveform of the no-load back electromotive force of a motor using the rotor punchings of the embodiment of the present invention and a motor with a prior art structure.

[0034] Figure 3 The figure is a bar graph comparing no-load back EMF wave harmonics of a motor using the rotor punchings of the embodiment of the present invention and a motor using a prior art structure.

[0035] Figure 4 The waveform diagram is a comparison of the cogging torque of a motor using the rotor punchings of the embodiment of the present invention and that of a motor using the prior art structure.

[0036] Figure 5 The electromagnetic torque waveform diagram of the motor using the rotor punchings of the embodiment of the present invention is compared with that of the existing structure.

[0037] In the figure: 1. rotor punching sheet; 2. permanent magnet slot; 3. permanent magnet; 4. permanent magnet slot; 5. first arc; 6. second arc; 7. trimming section; 8. magnetic isolation bridge; 9. magnetic rib; 10. shaft hole; 11. weight reduction and heat dissipation hole; 12. rivet hole; 13. full circle. DETAILED DESCRIPTION

[0038] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0039] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0041] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of the present invention. Meanwhile, it should be clear that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, method and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology, method and equipment should be considered as a part of the specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, and therefore, once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0042] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention: the directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0043] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below their position devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0044] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0045] The existing permanent magnet synchronous motor has poor back EMF sinusoidality and contains a large number of harmonics, which increases the torque pulsation of the motor, resulting in high vibration and noise in the entire compressor system, affecting customer comfort. Usually, measures such as stator skew slots, rotor skew poles, and combined magnetic poles are used to improve the back EMF waveform and suppress torque pulsation, but these measures will lead to problems such as a significant reduction in output torque and difficulty in process implementation.

[0046] In order to solve the above technical problems, the present invention proposes a rotor punching sheet, and also proposes a permanent magnet synchronous motor and a compressor, which relate to the field of compressor design and manufacturing, and to the field of design and manufacturing of a permanent magnet synchronous motor for a DC variable frequency compressor.

[0047] Reference below Figure 1-Figure 5 A rotor punching according to an embodiment of the present invention is described.

[0048] refer to Figure 1 The present invention provides a rotor punching sheet 1, which includes a punching sheet body, a shaft hole 10 is provided in the middle of the punching sheet body, a plurality of permanent magnet slots 2 uniformly distributed along the circumferential direction are provided at the circumferential position near the outer edge of the punching sheet body, p N-pole and p S-pole permanent magnets 3 are alternately inserted in the permanent magnet slots 2, and permanent magnet clamping slots 4 are provided at both ends of the permanent magnet slots 2 for fixing the permanent magnets 3. The outer edge of the punching sheet body is provided with a plurality of circular arc segments and a plurality of trimming segments uniformly distributed in the circumferential direction, and the outer edge line is a closed line formed by alternately setting and connecting a plurality of circular arc segments and a plurality of trimming segments 7, and the trimming segment 7 is a straight line segment. The arc segment includes a first arc 5 and two second arcs 6. The center of the first arc 5 is at the center of the rotor punching sheet. The second arc 6 is not concentric with the first arc 5. In this embodiment, the center of the second arc 6 is located outside the shaft hole 10. The two second arcs 6 are symmetrically distributed about the center line of the first arc 5 in the radial direction. The trimming segment 7 and the second arc 6 are tangent to each other, and the two ends of the trimming segment 7 are tangent to the second arc 6 on both sides respectively.

[0049] Define the center line of the permanent magnet 3 in the radial direction as the d-axis, which is the center line of the first arc 5 in the radial direction, and the center line between two adjacent permanent magnets 3 as the q-axis. Each trimming segment 7 is symmetrically arranged about the q-axis where it is located. The first arc 5, the two second arcs 6 and the half trimming segments 7 on both sides under one pole are symmetrically distributed with the d-axis as the axis of symmetry. The first arc 5, the second arc 6 and the trimming segments 7 corresponding to each pole are evenly distributed along the circumferential direction; the trimming segments 7 and the second arc 6 are tangent to each other and are symmetrically distributed with the d-axis as the axis of symmetry under one pole. The mechanical angle occupied by the permanent magnet 3 of each pole is 2θ, that is, the angle between the d-axis and the q-axis is θ, and the radius R of the first arc 5 is defined as 1 is the rotor radius, and the radius of the second arc 6 is R 2 , the center angle of the first arc 5 under a pole is α, the center angle of the second arc 6 is β, and the center angle of the arc 5 along the q axis is R1 The maximum vertical distance between the full circle 13 with a radius of h and the cutting edge segment 7 is h, satisfying the relationship 0<h=[1-cos(θ-α)]·(R 1 -R 2 )≤2.3mm.

[0050] The present invention can improve the sinusoidality of the back-electromotive force waveform by changing h and α, reduce the back-electromotive force harmonic distortion rate, and further weaken the torque pulsation to reduce vibration noise.

[0051] It should be noted that the rotor punching sheet 1 is formed by punching out an electromagnetic steel sheet having a specific shape.

[0052] Preferably, by adjusting R 1 The maximum vertical distance of the full circle 13 with a radius of h from the cutting edge segment 7 and the central angle α of the first arc 5 satisfy 0<h=[1-cos(θ-α)]·(R 1 -R 2 )≤2.3mm can make the air gap non-uniformly distributed, so as to improve the sinusoidality of the back-EMF waveform, reduce the back-EMF harmonic distortion rate, and suppress the torque pulsation.

[0053] Specifically, the number of N poles or S poles of the permanent magnet 3 of the rotor punching 1 has been determined at the beginning of the motor design, including but not limited to 3, 4, wherein the number of N poles and S poles of the permanent magnet 3 is equal, that is, the total number of permanent magnets 3 includes but is not limited to 6, 8. Figure 1 For example, the number of permanent magnets is 2p=6.

[0054] Preferably, in order to achieve specific power, output torque, efficiency and other indicators, the outer diameter of the rotor punching 1 is limited to 43.5 mm ≤ R 1 ≤55mm. Such as R 1 44mm, 48.5mm, 52.3mm, etc. Limited R 1 The range helps to standardize and serialize motor design and manufacturing, and provide a reasonable and reliable magnetic circuit to meet the performance indicators of the motor.

[0055] It can be understood that the angle θ=360° / 2p / 2 between the d-axis and the q-axis can be determined by the number of permanent magnets 3 determined above.

[0056] Furthermore, when R 1 After the maximum vertical distance of the full circle 13 with a radius of h from the trimming segment 7 and the center angle α of the first arc 5 are determined, the center angle α and radius R of the second arc 6 are 2 , and the center position C of the circle can be determined.

[0057] Specifically, the radius R of the second arc 6 is 2 =R 1-h / [1-cos(θ-α)], if h and α are changed, the radius R of the second arc 6 is 2 changes accordingly, and when h>0, R 2 <R 1 .

[0058] Specifically, the central angle β of the second arc 6 is θ-α-arctan[(R 1 -R 2 )·sin(θ-α) / (R 1 -h)], the coordinates of the center C of the second arc 6 in the xoy plane are ((R 1 -R 2 )·sin(θ-α),(R 1 -R 2 )·cos(θ-α)).

[0059] It should be noted that in order to reduce the back EMF harmonics, weaken the torque pulsation, ensure a smaller output electromagnetic torque loss, and consider the convenience of process manufacturing, it is necessary to reasonably select the size of h and α and ensure that 0°<α≤13°.

[0060] Furthermore, the permanent magnet slots 2 are evenly distributed in 2p numbers along the circumference, and the 2p permanent magnets 3 are inserted into the permanent magnet slots 2 alternately with N and S poles.

[0061] Specifically, there is a magnetic isolation bridge 8 between the permanent magnet slot 2 and the trimming section 7, and the thickness of the magnetic isolation bridge 8 is defined as w. b In order to ensure that the leakage coefficient is within a certain range and consider the mechanical strength of the electromagnetic steel plate, w b It can be between 0.6mm and 1.2mm, such as 0.60mm, 0.65mm, 0.8mm, etc. 1 When the value is relatively large or the motor runs at a high speed, w b Can be relatively large.

[0062] Optionally, there is a magnetic rib 9 between two adjacent permanent magnet slots 2, and the width of the magnetic rib 9 is defined as the vertical distance w between the adjacent permanent magnet slots 2. r In order to ensure that the leakage coefficient is within a certain range, the sine degree of the back EMF waveform is good or bad, and considering the mechanical strength of the electromagnetic steel plate, the required width and thickness of the permanent magnet 3 and other factors, it is necessary to meet 0.8mm≤w r ≤4.5mm.

[0063] Furthermore, the width of the permanent magnet 3 is defined as h m , thickness is b mThe permanent magnet 3 is rectangular in shape, and the four right angles can be chamfered according to the actual process. Considering the available space of the rotor punching, the required air gap flux density, the stator yoke flux density, the maximum demagnetization working point of the permanent magnet, the waveform sinusoidality of the no-load back EMF, the cogging torque, the torque ripple and other factors, it is necessary to ensure that 8.15 ≤ h m / b m ≤16, such as h m =38.6mm, b m =2.5mm, then h m / b m =15.44.

[0064] It should be noted that h m / b m It is dimensionless, but it can reflect the amount and shape of the permanent magnet 3. When the motor temperature rise is too high and needs to be operated with overload and high current for a long time, and h m / b m When the value is large, the permanent magnet 3 can be considered to be radially segmented. The number of segments and the width of each segment are selected according to the feasibility of the process. In this case, the sum of the lengths of each segment is b. m The thickness, magnetizing method, brand, etc. of each segment of permanent magnet 3 must be consistent.

[0065] Specifically, the rotor punchings of the present invention are axially stacked to the required thickness of the motor and riveted through the rivet holes 12, and the permanent magnets 3 are inserted into the permanent magnet slots 2. In order to ensure the power or torque required by the motor output, the residual magnetism (residual magnetic induction intensity) of the permanent magnets 3 must meet B r , and 12.2kGs≤B r ≤15.3kGs.

[0066] Furthermore, considering the manufacturability of the compressor, the axial view of the permanent magnet 3 is in the shape of a "one", and the permanent magnet 3 is inserted into the permanent magnet slot 2 and then magnetized, and it is necessary to ensure that the magnetic field direction of the permanent magnet 3 is parallel to the d-axis.

[0067] refer to Figure 1 The rotor punching 1 is provided with an axial hole 10 which is concentric with the rotation center of the rotor.

[0068] Optionally, a plurality of weight-reducing and heat-dissipating holes 11 are evenly arranged on the periphery of the shaft hole 10. By dynamically adjusting the size of the weight-reducing and heat-dissipating holes 11, the moment of inertia can be conveniently matched, and the inverter can be cooperated to obtain better dynamic and steady-state characteristics. In addition, the refrigerant circulation area can be increased to reduce the temperature rise of the motor body and increase the efficiency of the system.

[0069] Optionally, a plurality of rivet holes 12 are evenly arranged on the periphery of the shaft hole 10 to fix the rotor punching sheet 1 of the present invention.

[0070] The present invention also provides a permanent magnet synchronous motor, which uses the above rotor punching sheet 1. Other structures and operations of the permanent magnet synchronous motor are known to those skilled in the art and will not be described in detail.

[0071] It should be noted that the “existing structure” mentioned below specifically refers to a permanent magnet synchronous motor in which the outer edge of the rotor punching is not limited, that is, the outer circle of the rotor is a full circle 13 .

[0072] The present invention specifically refers to the limitation of 0<h=[1-cos(θ-α)]·(R 1 -R 2 )≤2.3mm and related parameters of permanent magnet synchronous motor.

[0073] like Figure 2 It is a comparison diagram of the no-load back EMF waveforms of the present invention and the prior art structure.

[0074] Specifically, the no-load back EMF of a permanent magnet motor is an important indicator. Its effective value determines the motor's efficiency, power factor, weak magnetic field speed expansion capability, etc. The sinusoidality of its waveform will affect the motor's output torque quality, electromagnetic vibration noise, etc.

[0075] Furthermore, it can be seen from the figure that the sinusoidality of the no-load back EMF waveform of the present invention is significantly better than that of the existing structure, which shows that the improvement measures of the present invention bring about significant performance improvement.

[0076] like Figure 3 It is a comparison diagram of no-load back EMF harmonic distribution of the present invention and the existing structure.

[0077] Specifically, since the high-order harmonics are very small compared to the low-order harmonics, only the 17th harmonic is displayed. As can be seen from the figure, although the fundamental amplitude of the present invention is slightly reduced, most of the subharmonics are greatly reduced. According to the calculation formula of the harmonic distortion rate, the back-EMF harmonic distortion rate of the existing structure is calculated to be 5.48%, while the back-EMF harmonic distortion rate of the present invention is only 1.37%, indicating that the back-EMF harmonic distortion rate can be significantly reduced after adopting the present invention, so that the performance is significantly improved.

[0078] like Figure 4 It is a comparison diagram of the cogging torque waveforms of the present invention and the existing structure.

[0079] Specifically, cogging torque is a common shortcoming of permanent magnet synchronous motors. Excessive cogging torque will affect the output of the motor's electromagnetic torque, positioning accuracy, etc., so certain measures need to be taken to weaken the cogging torque.

[0080] Furthermore, it can be seen from the figure that the peak-to-peak value of the cogging torque of the present invention is only 1.78Nm, while the peak-to-peak value of the cogging torque of the prior art structure is as high as 4.41Nm, indicating that the cogging torque is significantly improved after adopting the present invention.

[0081] like Figure 5 It is the output torque waveform diagram of the present invention and the existing structure at the rated point.

[0082] Specifically, the electromagnetic torque pulsation output by the motor will affect the electromagnetic vibration noise of the motor, and certain measures need to be taken to suppress it.

[0083] Furthermore, it can be seen from the figure that the peak-to-peak value of the electromagnetic torque of the existing structure is extremely large and the torque pulsation is large, while the peak-to-peak value of the electromagnetic torque of the present invention is small, which further shows that the use of the rotor punching 1 of the present invention can effectively improve the output torque quality of the motor, thereby achieving the purpose of reducing the vibration noise of the motor.

[0084] In summary, combined with the previously proposed back electromotive force sinusoidal difference of the permanent magnet synchronous motor, it contains a large number of harmonics, which increases the torque pulsation of the motor, thereby causing the entire compressor system to have large vibration and noise, affecting the customer's comfort. The present invention modifies the outer edge of the rotor punching 1 so that the parameter limit satisfies 0<h=[1-cos(θ-α)]·(R 1 -R 2 )≤2.3mm comprehensively improves the performance of the motor, which is specifically manifested in the excellent sinusoidality of the back-EMF waveform, low harmonic distortion rate, low cogging torque, small output electromagnetic torque pulsation, low electromagnetic vibration noise, etc., resulting in better performance in various applications.

[0085] The present invention also provides a compressor, which adopts the above permanent magnet synchronous motor. The other structures and operations of the compressor are known to those skilled in the art and will not be described in detail.

[0086] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A rotor punching, characterized in that: It comprises a punched sheet body, wherein the middle part of the punched sheet body is provided with an axial hole (10) concentric with the rotation center of the rotor, the punched sheet body is provided with a plurality of permanent magnet slots (2) evenly distributed in the circumferential direction, and p N-pole and p S-pole permanent magnets (3) are alternately inserted in the permanent magnet slots (2); The outer edge line of the punch body is a closed line formed by alternately arranging a plurality of arc segments and a plurality of trimming segments (7), the plurality of arc segments and the plurality of trimming segments (7) are evenly distributed along the circumferential direction, and the trimming segments (7) are straight line segments; The arc segment comprises a first arc (5) and two second arcs (6), the center of the first arc (5) is at the center of the rotor punching sheet, the second arc (6) is not concentric with the first arc (5), the two second arcs (6) are symmetrically distributed about the center line of the first arc (5) in the radial direction, and the two ends of the trimming segment (7) are tangent to the second arcs (6) on both sides respectively; The center line of each permanent magnet (3) in the radial direction is defined as the d-axis, the d-axis being the center line of the first arc (5) in the radial direction, and the center line between two adjacent permanent magnets (3) being the q-axis; Each of the trimming sections (7) is symmetrically arranged about the q axis on which it is located; The first circular arc (5), two second circular arcs (6) and half of the trimming segments (7) on both sides under a pole are symmetrically distributed with the d axis as the symmetry axis, and the first circular arc (5), the second circular arc (6) and the trimming segment (7) corresponding to each pole are evenly distributed along the circumferential direction; The mechanical angle occupied by the permanent magnet (3) is 2θ, that is, the angle between the adjacent d-axis and q-axis is θ, the radius R1 of the first circular arc (5) is defined as the rotor radius, and the radius of the second circular arc (6) is defined as R2; the center angle of the first circular arc (5) under a pole is α; the maximum vertical distance between the full circle (13) with the radius R1 and the trimming section (7) is h, satisfying the following relationship: 0<h=[1-cos(θ-α)]·(R1-R2)≤2.3mm.

2. The rotor punching according to claim 1, characterized in that: The value range of the radius R1 is: 43.5mm≤R1≤55mm.

3. The rotor punching according to claim 1, characterized in that: The included angle θ=360° / 2p / 2, and the center angle α of the first arc (5) satisfies 0°<α≤13°.

4. The rotor punching according to claim 1 or 3, characterized in that: The number of N poles and S poles of the permanent magnet (3) is equal, p=3 or p=4.

5. The rotor punching according to claim 1, characterized in that: A magnetic isolation bridge (8) is provided between the permanent magnet slot (2) and the trimming section (7), and the thickness w of the magnetic isolation bridge (8) is b Meet 0.6mm≤w b ≤1.2mm; A magnetic rib (9) is provided between two adjacent permanent magnet slots (2), and the width of the magnetic rib (9) is equal to the vertical distance w between the adjacent permanent magnet slots (2). r , and 0.8mm≤w r ≤4.5mm.

6. The rotor punching according to claim 1, characterized in that: The width of the permanent magnet (3) is h m , thickness is b m , and 8.15≤h m / b m ≤16; The residual magnetic induction intensity of the permanent magnet (3) is B r , and 12.2kGs≤B r ≤15.3kGs.

7. The rotor punching according to claim 1, characterized in that: The permanent magnet (3) is in the shape of an I, and the direction of the magnetic field is parallel to the d-axis.

8. The rotor punching according to claim 1, characterized in that: A plurality of weight-reducing and heat-dissipating holes (11) and a plurality of rivet holes (12) are evenly arranged on the periphery of the shaft hole (10).

9. A permanent magnet synchronous motor, characterized in that: The invention comprises a rotor punching sheet as claimed in any one of claims 1 to 8.

10. A compressor, characterized in that: A permanent magnet synchronous motor as claimed in claim 9 is used.

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