Rotor punching sheet

Abstract

The invention provides a rotor punching sheet, which is characterized in that a plurality of V-shaped magnet grooves are formed in the circumferential direction of the rotor punching sheet, and the opening of a V shape formed by the V-shaped magnet grooves faces outwards; an inter-pole magnetic bridge is arranged between every two V-shaped rotor magnet grooves; the rotor punching sheet is provided with a through hole, the through hole is arranged close to the inter-pole magnetic bridge, the through hole is closer to the centroid of the rotor punching sheet relative to the inter-pole magnetic bridge, and the through hole is used for reducing the second-order space electromagnetic force density of the rotor punching sheet. On the premise of ensuring the motor efficiency as far as possible, the radial electromagnetic force density under low, medium and high frequencies can be balanced, the medium and high frequency noise can be weakened, and the motor noise can be reduced.

Description

Technical Field

[0001] The invention relates to the technical field of motors, and in particular to a rotor punching sheet. Background Art

[0002] The mainstream household air conditioner compressors on the market now have noise points in the medium and high frequency bands (1200-2000HZ). The electromagnetic noise of the motor is directly related to its electromagnetic force and the motor structure mode. Since the variable frequency motor has a wide operating range, the impact of electromagnetic noise is spread over the low, medium and high frequency bands, and it is difficult to design the electromagnetic force density of the motor in different frequency bands to be at a low value. The industry lacks a simple and effective technical solution to solve the above problems. Summary of the invention

[0003] The purpose of the present invention is to provide a rotor punching which balances the radial electromagnetic force density at low, medium and high frequencies, weakens the radial second-order electromagnetic force density in the full frequency band, and reduces the noise of the compressor near 1200-2000HZ while ensuring the motor efficiency as much as possible.

[0004] To achieve the above-mentioned purpose, the present invention provides a rotor punching, wherein a plurality of V-shaped magnet grooves are arranged in the circumferential direction of the rotor punching, the V-shaped opening formed by the V-shaped magnet grooves faces outward, and a pole spacing magnetic bridge is provided between any two of the V-shaped rotor magnet grooves; a through hole is opened on the rotor punching, the through hole is arranged close to the pole spacing magnetic bridge, the through hole is closer to the centroid of the rotor punching than the pole spacing magnetic bridge, and the through hole is used to reduce the second-order spatial electromagnetic force density of the rotor punching.

[0005] Optionally, the pole spacing magnetic bridge is arranged at an angle with the V-shaped magnet groove to form a first corner point, and the minimum distance between the edge of the through hole and the first corner point is greater than or equal to 0.45 cm and less than or equal to 0.8 cm.

[0006] Optionally, the minimum distance between the edge of the through hole and the edge of the pole spacing magnetic bridge is greater than or equal to 0.45 cm and less than or equal to 0.8 cm.

[0007] Optionally, the through hole is circular and is also used to insert a fastener.

[0008] Optionally, the rotor punching also includes a first auxiliary groove, which is farther away from the centroid of the rotor punching relative to the V-shaped magnet groove, and the first auxiliary groove is located within the V-shaped opening range of the V-shaped magnet groove. An outer edge cutout is provided on the outer edge of the rotor punching, and the outer edge cutout is provided between two adjacent first auxiliary grooves within the V-shaped opening range of the V-shaped magnet groove.

[0009] Optionally, the outer edge cutout is provided between the first auxiliary slot and the magnetic pole axis of the rotor punching sheet.

[0010] Optionally, the rotor punching also includes a second auxiliary groove, which is farther away from the centroid of the rotor punching relative to the V-shaped magnet groove. The second auxiliary groove is located within the V-shaped opening range of the V-shaped magnet groove, and the outer edge cut is arranged between the first auxiliary groove and the second auxiliary groove.

[0011] Optionally, a second corner point is defined in the outer edge cutout, and the second corner point is located on the axis of the first auxiliary groove.

[0012] Optionally, the two ends of the opening of the outer edge cut are respectively the first endpoint and the second endpoint, the line connecting the first endpoint and the centroid of the rotor punching is the first line, the line connecting the second corner point and the centroid of the rotor punching is the second line, the line connecting the second endpoint and the centroid of the rotor punching is the third line, the angle between the first line and the magnetic pole axis is the first angle, the angle between the second line and the magnetic pole axis is the second angle, and the angle between the third line and the magnetic pole axis is the third angle, then: the absolute value of the difference between the first angle and the second angle is greater than or equal to 0.5 degrees; the absolute value of the difference between the second angle and the third angle is greater than or equal to 0.5 degrees.

[0013] Optionally, the two ends of the opening of the outer edge cutout are respectively a first endpoint and a second endpoint, a line connecting the first endpoint and the centroid of the rotor punching is a first line, a line connecting the second corner point and the centroid of the rotor punching is a second line, a line connecting the second endpoint and the centroid of the rotor punching is a third line, an angle between the first line and the magnetic pole axis is a first angle, an angle between the second line and the magnetic pole axis is a second angle, and an angle between the third line and the magnetic pole axis is a third angle; the distance between the second corner point and the first endpoint is less than the distance between the second corner point and the The distance between the second endpoint and the first endpoint is farther away from the magnetic pole axis within the V-shaped opening range of the V-shaped magnet groove than the second endpoint; the angle between the axis of the first auxiliary groove and one side of the V-shaped magnet groove intersecting therewith is θ, the first angle is θ1, the second angle is θ2, and the third angle is θ3, then: θ1-θ2=2.7-(θ-90); θ2-θ3=2.7+(θ-90); wherein, if the calculation result of 2.7-(θ-90) or 2.7+(θ-90) is a negative value, the calculation result is directly taken as 0.5.

[0014] The rotor punching provided by the present invention has the following beneficial effects:

[0015] The present invention provides a rotor punching sheet, wherein a plurality of V-shaped magnet grooves are arranged in the circumferential direction of the rotor punching sheet, the V-shaped opening formed by the V-shaped magnet grooves faces outward, and the pole spacing magnetic bridges are arranged on the outer sides of the V-shaped opening of the V-shaped magnet grooves; a through hole is opened on the rotor punching sheet, the through hole is closer to the centroid of the rotor punching sheet relative to the pole spacing magnetic bridge, the distance between the edge of the through hole and the pole spacing magnetic bridge is within a first preset range, and the through hole is used to reduce the second-order spatial electromagnetic force density of the rotor punching sheet. The inventor has found that mainstream household air-conditioning compressors have noise points in the medium and high frequency bands (1200-2000HZ), which is mainly because the structure of the household air-conditioning compressor determines that it has a second-order mode in the medium and high frequency bands (1200-2000HZ), which is easily excited by the spatial second-order electromagnetic force caused by the eccentric installation of the rotor of the motor, resulting in abnormal noise convex points in the compressor in the medium and high frequency bands. With such arrangement, the through hole designed in the present invention greatly optimizes the second-order spatial electromagnetic force while ensuring that the motor is unloaded, the load performance remains unchanged, and the density of other-order spatial electromagnetic forces does not increase significantly, thereby weakening the noise bumps of the compressor at medium and high frequencies (1200-2000HZ), and can be used as a low-noise motor rotor punching sheet for an air-conditioning compressor. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 An overall schematic diagram of a rotor punching provided in one embodiment of the present invention.

[0017] Figure 2 A schematic diagram of the positional relationship between the through holes of a rotor punching sheet, the V-shaped magnet slots, and the pole spacing magnetic bridge provided in one embodiment of the present invention.

[0018] Figure 3 It is a schematic diagram comparing the second-order radial electromagnetic force density at different frequencies without using the present invention and the second-order radial electromagnetic force density at different frequencies with using the present invention.

[0019] Figure 4 A schematic diagram of the position of the outer edge cutout on the outer edge of the rotor punching provided in one embodiment of the present invention.

[0020] Figure 5 A schematic diagram of the positional relationship between the outer edge cutout and the first auxiliary groove, the V-shaped magnet groove, and the magnetic pole axis provided in one embodiment of the present invention.

[0021] Figure 6 It is a schematic diagram comparing the changes in the waveform of the no-load generating potential of the motor after the through hole 13 and the outer edge cutout 21 are opened in one embodiment of the present invention.

[0022] Figure 7 It is a schematic diagram comparing the changes in output torque under the same current after the through hole 13 and the outer edge cutout 21 are opened in one embodiment of the present invention.

[0023] The accompanying drawings are denoted as follows:

[0024] 11-V-shaped magnet slot; 110-first corner point; 12-pole spacing magnetic bridge; 13-through hole; 14-first auxiliary slot; 140-axis of the first auxiliary slot; 15-shaft hole; 16-oil hole; 17-rivet hole;

[0025] 20-magnetic pole axis; 21-outer edge cut; 22-second auxiliary groove; 211-first end point; 210-second turning point; 212-second end point;

[0026] 101 - first connection line; 102 - second connection line; 103 - third connection line. DETAILED DESCRIPTION

[0027] In order to make the purpose, advantages and features of the present invention clearer, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the drawings are all in a very simplified form and are not drawn to scale, and are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention. In addition, the structure shown in the drawings is often a part of the actual structure. In particular, the emphasis of each drawing is different, and sometimes different scales are used.

[0028] It should be understood that when an element or layer is referred to as "on...", "connected to" other elements or layers, it can be directly on other elements or layers, connected to other elements or layers, or can include intermediate elements or layers. On the contrary, when an element is referred to as "directly on...", "directly connected to" other elements or layers, intermediate elements or layers are not included. Although the terms first, second, third, etc. can be used to describe various elements, components, regions, layers and / or parts, these elements, components, regions, layers and / or parts should not be limited by these terms. These terms are only used to distinguish an element, component, region, layer or part from another element, component, region, layer or part. Therefore, without departing from the teachings of the present invention, the first element, component, region, layer or part discussed below can be expressed as a second element, component, region, layer or part. Spatial relationship terms such as "under...", "below", "below", "above...", "above", "above", etc., can be used here for the convenience of description to describe the relationship between an element or feature shown in the figure and other elements or features. It should be understood that, in addition to the orientation shown in the figure, the spatial relationship terms are intended to include different orientations of the devices in use and operation. For example, if the device in the accompanying drawings is turned over, then, the elements or features described as "under...", "below", "below" will be oriented to be "on" other elements or features. The device can be oriented in addition (rotated 90 degrees or other orientations) and the spatial descriptors used herein are interpreted accordingly. The purpose of the terms used herein is only to describe specific embodiments and is not intended to be a limitation of the present invention. When used herein, the singular forms of "one", "one" and "said / the" are also intended to include plural forms, unless the context clearly indicates another way. It should also be understood that the term "include" is used to determine the inclusion of features, steps, operations, elements and / or parts, but does not exclude the inclusion or addition of one or more other features, steps, operations, elements, parts and / or groups. When used herein, the term "and / or" includes any and all combinations of the relevant listed items.

[0029] The object of the present invention is to provide a rotor punching which balances the radial electromagnetic force density at low, medium and high frequencies, weakens medium and high frequency noise, and reduces compressor noise while ensuring motor efficiency as much as possible.

[0030] Please refer to Figure 1 , Figure 1 The overall schematic diagram of the rotor punching provided by one embodiment of the present invention. Figure 1As shown, in order to achieve the above purpose, the present invention provides a rotor punching, wherein a plurality of V-shaped magnet grooves 11 are provided in the circumferential direction of the rotor punching, the V-shaped opening formed by the V-shaped magnet grooves 11 faces outward, and there is a pole spacing magnetic bridge 12 between any two of the V-shaped rotor magnet grooves 11, that is, there are pole spacing magnetic bridges 12 on both sides of the V-shaped opening of the V-shaped magnet grooves 11; a through hole 13 is provided on the rotor punching, and the through hole 13 is closer to the centroid of the rotor punching relative to the pole spacing magnetic bridge 12, and the through hole 13 is arranged close to the pole spacing magnetic bridge 12, that is, the distance between the edge of the through hole 13 and the pole spacing magnetic bridge 12 is within the first preset range, and the through hole 13 is used to reduce the second-order spatial electromagnetic force density of the rotor punching. According to the conventional setting, it should also include an axial hole 15, an oil hole 16, a rivet hole 17, etc., which will not be repeated here.

[0031] The inventor has found that mainstream household air-conditioning compressors have noise points in the medium and high frequency bands (1200-2000HZ), which is mainly because the structure of household air-conditioning compressors determines that they have second-order modes in the medium and high frequency bands (1200-2000HZ). This mode is easily excited by the second-order electromagnetic force in space caused by the eccentric installation of the motor rotor, resulting in abnormal noise bumps in the compressor in the medium and high frequency bands. In this way, the through hole designed in the present invention greatly optimizes the second-order spatial electromagnetic force while ensuring that the motor is unloaded, the load performance remains unchanged, and the density of other-order spatial electromagnetic forces does not increase significantly, thereby weakening the noise bumps of the compressor in the medium and high frequency (1200-2000HZ), and can be used as a low-noise motor rotor punching for air-conditioning compressors.

[0032] It should be noted that the through hole should be as close to the V-shaped magnet slot 11 and the pole spacing magnetic bridge 12 as possible under the premise of ensuring the strength of the rotor punching sheet, so as to reduce the second-order spatial electromagnetic force density of the rotor punching sheet, and at the same time, the through hole should not be too close to the V-shaped magnet slot 11 and the pole spacing magnetic bridge 12, which will cause the body strength to decrease and thus be damaged. The size of the first preset range should be determined based on this principle. For details, please refer to Figure 2 , Figure 2 Schematic diagram of the positional relationship between the through hole 13 of the rotor punching sheet, the V-shaped magnet slot 11 and the pole spacing magnetic bridge 12 provided in one embodiment of the present invention. Figure 2As shown, the pole spacing magnetic bridge 12 and the V-shaped magnet groove 11 can be set at an angle to form a first corner point 110, and the first corner point 110 is used as a reference for the setting position of the through hole 13. In an exemplary embodiment, the minimum distance from the edge of the through hole 13 to the first corner point 110 is greater than or equal to 0.45 cm and less than or equal to 0.8 cm, but it is not limited to this. Another position reference object of the through hole 13 can be the pole spacing magnetic bridge 12, and the minimum distance from the edge of the through hole 13 to the edge of the pole spacing magnetic bridge 12 is greater than or equal to 0.45 cm and less than or equal to 0.8 cm, but it is not limited to this. Figure 2 In the embodiment shown, the through hole 13 is a square, which can be further simplified as follows: considering the positional relationship between the square and the V-shaped magnet slot 11 and the pole spacing magnetic bridge 12, based on the centroid conversion of the through hole 13 Figure 2 The size of L1 and L2 determines the position of the through hole 13, and further determines the size of the through hole 13 itself. In an exemplary embodiment, the through hole 13 is a square, and its side length L3 can be set between 1.2 cm and 2 cm, but it is not limited to this.

[0033] Furthermore, the through hole 13 may be set to be circular, in which case the through hole 13 is also used to insert a fastener, thereby serving as a connection point for the fastener, further reinforcing the rotor punching sheet, and achieving multiple uses of one hole. It should be noted that the shape of the through hole 13 may also be other shapes, such as Figure 1 Figure 2 The square shown will not be described in detail here.

[0034] Please refer to Figure 3 , Figure 3 It is a schematic diagram comparing the second-order radial electromagnetic force density at different frequencies without using the present invention and the second-order radial electromagnetic force density at different frequencies using the present invention. Figure 3 We can find that after using the present invention, the spatial second-order radial electromagnetic force density at different frequencies is greatly reduced. The specific comparative data can also be referred to the following two tables. Table 1 shows the spatial radial electromagnetic force density of each order at different frequencies without using the present invention, and Table 2 shows the radial electromagnetic force density of each order at different frequencies using the present invention.

[0035]

[0036] Table 1

[0037]

[0038] Table 2

[0039] For further information, please refer to Figure 4 , Figure 4A schematic diagram of the position of the outer edge cutout on the outer edge of the rotor punching provided for one embodiment of the present invention. The rotor punching also includes a first auxiliary groove 14, which is farther away from the centroid of the rotor punching relative to the V-shaped magnet groove 11, and the first auxiliary groove 14 is located within the V-shaped opening range of the V-shaped magnet groove 11. An outer edge cutout 21 is provided on the outer edge of the rotor punching, and the outer edge cutout 21 is provided between two adjacent first auxiliary grooves 14 within the V-shaped opening range of the V-shaped magnet groove 11. Such a setting can further reduce the eccentric radial electromagnetic force density of the motor and further reduce the motor noise. It should be understood that the first auxiliary groove 14 is generally axially symmetrical about the magnetic pole axis 20 within the V-shaped opening range of the V-shaped magnet groove, so similarly, the outer edge cutout 21 should also be axially symmetrical about the magnetic pole axis 20 within the V-shaped opening range of the V-shaped magnet groove. The outer edge cutout 21 should be provided between the first auxiliary groove 14 and the magnetic pole axis 20 of the rotor punching.

[0040] Furthermore, the rotor punching also includes a second auxiliary groove 22, which is farther away from the centroid of the rotor punching relative to the V-shaped magnet groove 11. The second auxiliary groove 22 is located within the V-shaped opening range of the V-shaped magnet groove 11. At this time, the outer edge cutout 21 should be located between the first auxiliary groove 14 and the second auxiliary groove 22.

[0041] The shape of the outer edge cutout 21 is generally a check mark shape, but it can also be other shapes, but the position of the outer edge cutout 21 needs to be determined to reduce the eccentric radial electromagnetic force density of the motor. The following describes the idea of ​​determining the position of the outer edge cutout 21.

[0042] Generally speaking, the outer edge cutout 21 should be in the high saturation magnetic flux density area formed on the outer edge of the rotor. The outer edge cutout 21 should be located around the extension line from the center line of the rotor magnetic flux sorting groove (the first auxiliary groove 14 and the second auxiliary groove 22 are both magnetic flux sorting grooves, the purpose of which is to adjust the direction of the magnetic flux lines) to the outer edge of the rotor, in order to eliminate the high magnetic flux density area formed by the rotor magnetic flux sorting groove.

[0043] Please refer to Figure 5 , Figure 5 A schematic diagram of the positional relationship between the outer edge cutout and the first auxiliary groove, the V-shaped magnet groove, and the magnetic pole axis provided in one embodiment of the present invention. Figure 5 As shown, the outer edge cutout 21 has a second corner point 210, and the second corner point 210 is located on the axis 140 of the first auxiliary slot. It should be understood that in this case, the axis of the first auxiliary slot 14 as a straight line should be able to intersect with the outer edge of the V-shaped magnet slot 11 and the rotor punching.

[0044] Further, the opening ends of the outer edge cutout 21 are respectively a first endpoint 211 and a second endpoint 212, the line connecting the first endpoint 211 and the centroid of the rotor sheet is the first line 101, the line connecting the second corner point 210 and the centroid of the rotor sheet is the second line 102, the line connecting the second endpoint 212 and the centroid of the rotor sheet is the third line 103, the angle between the first line 101 and the magnetic pole axis 20 is the first angle, the angle between the second line 102 and the magnetic pole axis 20 is the second angle, and the angle between the third line 103 and the magnetic pole axis 20 is the third angle, which satisfies: the absolute value of the difference between the first angle and the second angle is greater than or equal to 0.5 degrees; the absolute value of the difference between the second angle and the third angle is greater than or equal to 0.5 degrees. Such a setting can limit the position of the outer edge cutout 21.

[0045] Preferably, when the angle between the axis 140 of the first auxiliary groove and the side of the V-shaped magnet groove 11 intersecting therewith is introduced, the new limiting principle of the position of the outer edge cutout 21 should be introduced. Under this premise. The distance between the second corner point 210 and the first end point 211 should be smaller than the distance between the second corner point 210 and the second end point 212, and the first end point 211 is farther away from the magnetic pole axis 20 within the V-shaped opening range of the V-shaped magnet groove 11 relative to the second end point 212; the angle between the axis 140 of the first auxiliary groove and the side of the V-shaped magnet groove 11 intersecting therewith is θ, the first angle is θ1, the second angle is θ2, and the third angle is θ3, which satisfies: θ1-θ2=2.7-(θ-90); θ2-θ3=2.7+(θ-90); wherein, if the calculation result of 2.7-(θ-90) or 2.7+(θ-90) is a negative value, the calculation result is directly taken as 0.5.

[0046] Figure 6 The waveform of the motor's no-load potential is shown after the through hole 13 and the outer edge cutout 21 are opened in an embodiment of the present invention. The effective value is reduced from the original 44.15V to 44.11V (the back EMF drops by 0.081% and remains almost unchanged), and the THD increases from 1.69% to 1.70%, proving that the through hole 13 of the present invention has almost no effect on the effective value and waveform of the motor's back EMF. After adding the outer edge cutout 21, the back EMF is reduced from the original 44.15V to 43.89V (the back EMF drops by 0.6%), and the THD increases from 1.69% to 1.90%.

[0047] Figure 7The output torque under the same current after the through hole 13 and the outer edge cutout 21 are opened in one embodiment of the present invention is shown, which decreases from 3.975Nm to 3.965Nm (decreases by 0.25%), and the torque fluctuation increases from 0.514Nm to 0.523Nm (increases by 1.75%). It can be seen that the through hole 13 of the present invention has almost no effect on the motor load operation. After adding the outer edge cutout 21, the motor output efficiency will be slightly reduced.

[0048] It should also be noted that, although the present invention has been disclosed as a preferred embodiment, the above embodiment is not intended to limit the present invention. For any technician familiar with the art, without departing from the scope of the technical solution of the present invention, the technical content disclosed above can be used to make many possible changes and modifications to the technical solution of the present invention, or modified into equivalent embodiments of equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the scope of protection of the technical solution of the present invention.

[0049] It should also be understood that, unless otherwise specified or indicated, the terms "first", "second", "third", etc. in the specification are merely used to distinguish between the various components, elements, steps, etc. in the specification, and are not used to indicate the logical relationship or sequential relationship between the various components, elements, steps, etc.

[0050] It should also be recognized that the terms described herein are used only to describe specific embodiments and are not intended to limit the scope of the invention. It should be noted that the singular forms "a" and "an" used herein and in the appended claims include plural references unless the context clearly indicates otherwise. For example, a reference to "a step" or "a device" means a reference to one or more steps or devices, and may include secondary steps and secondary devices. All conjunctions used should be understood in the broadest sense. And, the word "or" should be understood to have the definition of a logical "or", rather than a logical "exclusive or", unless the context clearly indicates otherwise. In addition, the implementation of embodiments of the present invention may include performing selected tasks manually, automatically, or in combination.

Claims

1. A rotor punching, characterized in that: A plurality of V-shaped magnet grooves are arranged in the circumferential direction of the rotor punching sheet, the V-shaped openings formed by the V-shaped magnet grooves face outwards, and a pole spacing magnetic bridge is provided between any two of the V-shaped rotor magnet grooves; A through hole is provided on the rotor punching sheet, and the through hole is arranged close to the pole spacing magnetic bridge. The through hole is closer to the centroid of the rotor punching sheet than the pole spacing magnetic bridge, and the through hole is used to reduce the second-order spatial electromagnetic force density of the rotor punching sheet.

2. The rotor punching according to claim 1, characterized in that: The pole spacing magnetic bridge is arranged at an angle with the V-shaped magnet groove to form a first corner point, and the minimum distance between the edge of the through hole and the first corner point is greater than or equal to 0.45 cm and less than or equal to 0.8 cm.

3. The rotor punching according to claim 2, characterized in that: The minimum distance between the edge of the through hole and the edge of the pole spacing magnetic bridge is greater than or equal to 0.45 cm and less than or equal to 0.8 cm.

4. The rotor punching according to claim 1, characterized in that: The through hole is circular and is also used for inserting a fastener.

5. The rotor punching according to claim 1, characterized in that: The rotor punching sheet also includes a first auxiliary groove, which is farther away from the centroid of the rotor punching sheet relative to the V-shaped magnet groove, and the first auxiliary groove is located within the V-shaped opening range of the V-shaped magnet groove. An outer edge cutout is provided on the outer edge of the rotor punching sheet, and the outer edge cutout is provided between two adjacent first auxiliary grooves within the V-shaped opening range of the V-shaped magnet groove.

6. The rotor punching according to claim 5, characterized in that: The outer edge cutout is arranged between the first auxiliary groove and the magnetic pole axis of the rotor punching sheet.

7. The rotor punching according to claim 5, characterized in that: The rotor punching sheet also includes a second auxiliary groove, which is farther away from the centroid of the rotor punching sheet relative to the V-shaped magnet groove. The second auxiliary groove is located within the V-shaped opening range of the V-shaped magnet groove, and the outer edge cutout is arranged between the first auxiliary groove and the second auxiliary groove.

8. The rotor punching according to claim 5, characterized in that: The outer edge cutout has a second corner point therein, and the second corner point is located on the axis of the first auxiliary groove.

9. The rotor punching according to claim 8, characterized in that: The two ends of the opening of the outer edge cut are respectively the first endpoint and the second endpoint, the line connecting the first endpoint and the centroid of the rotor punching is the first line, the line connecting the second corner point and the centroid of the rotor punching is the second line, the line connecting the second endpoint and the centroid of the rotor punching is the third line, the angle between the first line and the magnetic pole axis is the first angle, the angle between the second line and the magnetic pole axis is the second angle, and the angle between the third line and the magnetic pole axis is the third angle, then: the absolute value of the difference between the first angle and the second angle is greater than or equal to 0.5 degrees; the absolute value of the difference between the second angle and the third angle is greater than or equal to 0.5 degrees.

10. The rotor punching according to claim 8, characterized in that: The two ends of the opening of the outer edge cutout are respectively a first end point and a second end point, a line connecting the first end point and the centroid of the rotor punching is a first line, a line connecting the second corner point and the centroid of the rotor punching is a second line, a line connecting the second end point and the centroid of the rotor punching is a third line, an angle between the first line and the magnetic pole axis is a first angle, an angle between the second line and the magnetic pole axis is a second angle, and an angle between the third line and the magnetic pole axis is a third angle; The distance between the second turning point and the first end point is smaller than the distance between the second turning point and the second end point, and the first end point is farther away from the magnetic pole axis within the V-shaped opening range of the V-shaped magnet groove than the second end point; The angle between the axis of the first auxiliary slot and one side of the V-shaped magnet slot intersecting therewith is θ, the first angle is θ1, the second angle is θ2, and the third angle is θ3, then: θ1-θ2=2.7-(θ-90); θ2-θ3=2.7+(θ-90); If the calculation result of 2.7-(θ-90) or 2.7+(θ-90) is a negative value, the calculation result is directly taken as 0.5.

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