CN216699640U - Rotor punching sheet and high-speed permanent magnet synchronous motor - Google Patents

Abstract

The utility model discloses a rotor punching sheet and a high-speed permanent magnet synchronous motor, wherein a plurality of double-V-shaped magnet grooves are uniformly formed in the rotor punching sheet along the circumferential direction, each double-V-shaped magnet groove comprises a first V-shaped groove and a second V-shaped groove which are distributed from outside to inside along the radial direction, a V-shaped opening of each second V-shaped groove faces outwards along the radial direction, a second middle magnetic isolation bridge is arranged at a V-shaped tip part, a second outer magnetic isolation bridge is arranged at a V-shaped tail part, a plurality of unloading grooves which are uniformly distributed along the circumferential direction are further formed in the rotor punching sheet, each unloading groove is positioned between each double-V-shaped magnet groove and a shaft hole and is positioned on a symmetrical line of two adjacent double-V-shaped magnet grooves, and each unloading groove is formed by tangent multi-section arcs. On the premise of the existing punching sheet material performance, the problem of overlarge stress of the rotor punching sheet caused by high speed is solved, and the operation reliability of the rotor punching sheet can be effectively ensured. The high-speed permanent magnet synchronous motor provided by the utility model has the advantages because the rotor punching sheet is arranged.

Description

Rotor punching sheet and high-speed permanent magnet synchronous motor

Technical Field

The utility model belongs to the technical field of motors, and particularly relates to a rotor punching sheet and a high-speed permanent magnet synchronous motor.

Background

With the rapid development of new energy vehicles, permanent magnet synchronous motors for vehicles are gradually developing to high power density and high speed. The motor can be divided into a high-speed motor, a low-speed motor and the like according to the operation speed, wherein the high-speed motor generally refers to a motor with the rotating speed of more than 10000rpm, the rotating speed of the high-speed motor is required to be more than 20000rpm according to actual requirements, and the motor has higher requirements on rotor punching. On one hand, the traditional method for improving the strength of the rotor can increase the structural strength of the rotor sheet, but the performance of the motor is inevitably reduced by increasing the width of the magnetic isolation bridge, and the high power density is difficult to achieve, so that the high power density and the high rotating speed can be regarded as two contradictory requirements, and the existing design method is difficult to meet simultaneously; on the other hand, the yield strength of the rotor punching sheet material is improved on the basis of low iron loss and high magnetic induction, so that the cost is greatly increased. The existing technical scheme does not specially design the high rotating speed (the rotating speed is more than or equal to 20000r/min), how to optimize the mechanical stress distribution condition on the rotor punching sheet under the high rotating speed while ensuring the electromagnetic performance under the material performance of the existing punching sheet, and further realize the high-speed purpose of the rotor, and the problem to be solved at present is urgently solved.

SUMMERY OF THE UTILITY MODEL

The utility model aims to overcome the defects of the prior art and provide a rotor punching sheet and a high-speed permanent magnet synchronous motor which can meet high power density and realize high rotation speed.

In order to solve the technical problems, the utility model adopts the following technical scheme:

the utility model provides a rotor punching, the centre of a circle department of rotor punching has seted up the shaft hole, evenly seted up a plurality of two V-arrangement magnet grooves along circumference on the rotor punching, two V-arrangement magnet grooves include along radial outside-in first V-arrangement groove and the second V-arrangement groove that distributes, the V-arrangement opening in second V-arrangement groove is equipped with the second in radial outside, V-arrangement afterbody and is equipped with the second and separate the magnetic bridge outward, still set up a plurality of uninstallation grooves of evenly arranging along circumference on the rotor punching, the uninstallation groove be located between two V-arrangement magnet grooves and the shaft hole to be located on the line of symmetry in two adjacent two V-arrangement magnet grooves, the uninstallation groove is tangent to form by the multistage circular arc.

Preferably, the ratio of the radial width M1 of the unloading groove to the circumferential width M2 of the rotor sheet is 0.5-0.6, and the ratio of the radial width M1 of the unloading groove to the radius of the rotor sheet is 0.14-0.16.

Preferably, the rotor punching sheet is further provided with a plurality of lightening holes which are uniformly distributed along the circumferential direction, the lightening holes are located on the symmetrical center line of the double-V-shaped magnet grooves, and the distance from the unloading groove to the circle center of the rotor punching sheet is greater than the distance from the lightening holes to the circle center of the rotor punching sheet.

Preferably, the ratio of the distances from the centers of the unloading grooves and the lightening holes to the circle center of the rotor sheet is 1.25-1.35.

Preferably, the lightening holes are elliptical holes, the long axes of the elliptical holes are perpendicular to the radial direction, and the ratio of the distance from the centers of the lightening holes to the circle center of the rotor sheet to the radius of the rotor sheet is 0.5-0.55.

The rotor punching sheet is preferable, the second V-shaped groove comprises two second magnet grooves which are V-shaped and radially symmetrical, a second middle magnetic isolation bridge is formed between the near-axis hole ends of the second magnet grooves, the far-axis hole ends of the second magnet grooves and the periphery of the rotor punching sheet respectively form a second outer magnetic isolation bridge, the near-axis hole ends of the second magnet grooves are formed by multiple sections of arc lines in a tangent mode, and the width of the second middle magnetic isolation bridge is widened from the middle to the two ends.

Preferably, the arc lines include a first arc line with a radius of R1, a second arc line with a radius of R2, a third arc line with a radius of R3, and a fourth arc line with a radius of R4, where R1 ═ R3 is greater than or equal to 3mm, R2 ═ 2R1, and the size of R4 is determined by the minimum distance S between the second middle magnetic bridge and the unloading groove, and S is greater than or equal to 3.5 mm.

The rotor punching sheet is preferable, the far shaft hole end of the second magnet groove is an arc edge, the arc edge is formed by multiple sections of arcs in a tangent mode, the arc edge is connected with the long edge, located on the inner side of the V-shaped, of the second magnet groove through the transition arc, and an included angle exists between the tangent line of the transition arc and the extension line of the long edge.

According to the rotor punching sheet, preferably, a self-buckling point is arranged between every two adjacent second V-shaped grooves, a self-buckling point is arranged between each first V-shaped groove and each second V-shaped groove, the self-buckling points are uniformly arranged along the circumferential direction of the rotor punching sheet, and the ratio of the distance from the center of each self-buckling point to the circle center of the rotor punching sheet to the radius of the rotor punching sheet is 0.80-0.84.

Preferably, the first V-shaped groove comprises two first magnet grooves which are arranged in a V shape and are radially symmetrical, the opening of the V shape faces outwards along the radial direction, a first middle magnetic isolation bridge is formed between the near-axis hole ends of the two first magnet grooves, the far-axis hole ends of the two first magnet grooves and the periphery of the rotor sheet respectively form a first outer magnetic isolation bridge, and the ratio of the minimum width of the second middle magnetic isolation bridge to the width of the first middle magnetic isolation bridge is 1.5-3.0.

Preferably, the ratio of the minimum width of the first outer magnetic isolation bridge to the width of the second outer magnetic isolation bridge is 0.90-1.00.

Preferably, in the rotor sheet, the ratio of the V-shaped angle of the first V-shaped groove to the V-shaped angle of the second V-shaped groove is 1.33 to 1.43.

Preferably, in the rotor sheet, the ratio of the areas of the magnet-containing regions of the first V-shaped groove and the second V-shaped groove is 0.27-0.32.

In the rotor sheet, preferably, the sum of the areas of the lightening holes and the unloading grooves accounts for 19.37% of the total area of the rotor sheet.

As a general technical concept, the utility model also provides a high-speed permanent magnet synchronous motor which comprises a rotating shaft and the rotor punching sheet.

Preferably, the rotating shaft and the rotor sheet are in interference fit.

Preferably, the rotating shaft is a hollow rotating shaft, and the ratio of the inner diameter of the rotating shaft to the outer diameter of the rotating shaft is 0.5-0.6.

The design principle of the utility model is as follows:

(1) and aiming at the original rotor punching sheet design model and loading conditions such as loading rotating speed and temperature, and carrying out simulation calculation to obtain a stress distribution result of the rotor punching sheet.

(2) And (3) with the interference magnitude between the rotor punching sheet and the rotating shaft as a parameter variable and the bearing torque T of the rotor as a target, performing parameter optimization to obtain the minimum interference magnitude capable of meeting the bearing requirement, and selecting to obtain the maximum interference magnitude according to the processing capacity of the process.

(3) On the basis of the set interference magnitude, the area below the second middle magnetism isolating bridge is selected as an optimization area, the minimum size is taken as a target, topology optimization is carried out, and the position and the shape size of the lightening hole are obtained.

(4) On the basis, an unloading groove is formed, a first middle magnetic isolation bridge, a first outer magnetic isolation bridge, a second middle magnetic isolation bridge and a second outer magnetic isolation bridge are selected at the same time, the second middle magnetic isolation bridge is an optimized area, the stress is minimized, the shape is optimized, and the rotor punching sheet design scheme capable of meeting the interference range is obtained.

Compared with the prior art, the utility model has the advantages that:

the utility model provides a rotor punching sheet structure which can meet the electromagnetic performance and the high-speed operation, the rotor punching sheet adopts a double-V-shaped magnet groove structure, the number of magnetic isolation bridges is increased, the stress borne by each magnetic isolation bridge is more uniformly dispersed, the rotor punching sheet can bear the centrifugal force under the high rotating speed, and an unloading groove formed by tangent multiple sections of circular arcs is positioned on the symmetrical line of two adjacent double-V-shaped magnet grooves, so that the peak stress of a second middle magnetic isolation bridge can be reduced, and the non-uniformity of the deformation of two ends of the second outer magnetic isolation bridge under the high-speed operation can be improved. The rotor punching sheet provided by the utility model has the advantages that on the premise of the existing punching sheet material performance, the electromagnetic performance is ensured, the purpose of high speed of the rotor is realized, the problem of overlarge stress of the rotor punching sheet caused by high speed is solved, and the operation reliability of the rotor punching sheet can be effectively ensured.

The high-speed permanent magnet synchronous motor provided by the utility model has the advantages of the rotor punching sheet because the rotor punching sheet is installed.

Drawings

Fig. 1 is a schematic structural diagram of a rotor sheet according to the present invention.

Fig. 2 is an enlarged schematic view of a middle magnetic isolation bridge and an outer magnetic isolation bridge of the rotor punching sheet.

Fig. 3 is an enlarged schematic view of the unloading slots on the rotor punches of the present invention.

Fig. 4 is a stress comparison graph of the rotor sheet of the present invention with a rotor sheet without relief grooves.

Fig. 5 is an enlarged schematic view of a second intermediate magnetic bridge of the rotor sheet according to the present invention.

FIG. 6 is a stress comparison graph of the rotor sheet of the present invention and a second intermediate magnetic bridge having the same width.

Fig. 7 is an enlarged schematic view of a second outer magnetic isolation bridge of the rotor punching sheet of the utility model.

FIG. 8 is a stress comparison diagram of the rotor sheet of the present invention and the rotor sheet without an included angle between the outer end of the second outer magnetic isolation bridge and the long side.

Illustration of the drawings:

1. a shaft hole; 2. a first V-shaped groove; 21. a first magnet groove; 22. a first intermediate magnetically isolating bridge; 23. a first outer magnetic isolation bridge; 3. a second V-shaped groove; 31. a second magnet groove; 311. a long side; 32. a second intermediate magnetic isolation bridge; 33. a second outer magnetic isolation bridge; 4. lightening holes; 5. unloading the trough; 6. a circular arc line; 61. a first arc line; 62. a second arc line; 63. a third arc line; 64. a fourth arc line; 71. an arc-shaped edge; 72. a transition arc; 8. self-buckling points; 9. a rotating shaft.

Detailed Description

The present invention will be described in further detail with reference to the following specific embodiments and the accompanying drawings.

Fig. 1 to 8 show an embodiment of a rotor sheet according to the present invention, the center of the rotor sheet is provided with an axial hole 1, the rotor sheet is uniformly provided with a plurality of double V-shaped magnet slots, specifically eight double V-shaped magnet slots, each double V-shaped magnet slot comprises a first V-shaped slot 2 and a second V-shaped slot 3 distributed from outside to inside along the radial direction, the first V-shaped slot 2 comprises two first magnet slots 21 arranged in a V shape and radially symmetrical, the second V-shaped slot 3 comprises two second magnet slots 31 arranged in a V shape and radially symmetrical, the openings of the V shape are both outward along the radial direction, the V-shaped tips face the axial hole 1 along the radial direction, a first middle magnetic separation bridge 22 is formed between the near axial hole ends of the two first magnet slots 21, the far axial hole ends of the two first magnet slots 21 respectively form a first outer magnetic separation bridge 23 with the outer periphery of the rotor sheet, a second middle magnetic separation bridge 32 is formed between the near axial hole ends of the two second magnet slots 31, far shaft hole ends of the two second magnet grooves 31 and the periphery of the rotor sheet respectively form a second outer magnetic isolation bridge 33; the rotor punching sheet is further provided with a plurality of unloading grooves 5 which are uniformly distributed along the circumferential direction, the unloading grooves 5 are positioned between the double-V-shaped magnet grooves and the shaft hole 1 and positioned on the symmetrical lines of the two adjacent double-V-shaped magnet grooves, and the unloading grooves 5 are formed by tangency of multiple sections of circular arcs.

When a traditional single V-shaped rotor punching sheet rotates at a high speed, the stress action generated by centrifugal force can be concentrated on the magnetic isolation bridge, and the magnetic isolation bridge is easily damaged. The rotor punching sheet of the embodiment adopts a double-V-shaped magnet groove structure, the number of the magnetic isolation bridges is increased, the stress borne by each magnetic isolation bridge can be more uniformly dispersed, and the rotor punching sheet can bear the centrifugal force action at a high rotating speed. More importantly, in the embodiment, the unloading groove 5 formed by tangently connecting a plurality of circular arcs not only can reduce the peak stress of the second middle magnetic isolation bridge 32, but also can improve the non-uniformity of the deformation of the two ends of the second outer magnetic isolation bridge 33 under high-speed operation.

As shown in fig. 3, the shape appearance of the unloading groove 5 is similar to a "steamed stuffed bun", and is obtained by fitting a plurality of segments of tangent arcs based on a shape optimization algorithm, and the shape can reduce the stress concentration effect of the unloading groove 5 itself to the maximum extent, and is obtained by fitting eight segments of tangent arcs in the embodiment.

As shown in fig. 4a, the maximum stress of the second middle flux-isolated bridge 32 on the rotor sheet with the unloading groove 5 in this embodiment is 376.26MPa, and as shown in fig. 4b, the maximum stress of the second middle flux-isolated bridge on the rotor sheet without the unloading groove 5 is 481.88MPa, which is 22% lower than the stress result of this embodiment, and can effectively improve the operational reliability of the sheet.

In this embodiment, the ratio of the radial width M1 of the unloading groove 5 to the circumferential width M2 is 0.5, and the ratio of the radial width M1 of the unloading groove 5 to the radius of the rotor sheet is 0.15.

In the embodiment, the rotor punching sheet is further provided with a plurality of lightening holes 4 which are uniformly distributed along the circumferential direction, the lightening holes 4 are positioned on the symmetrical center line of the double-V-shaped magnet groove, and the distance from the unloading groove 5 to the circle center of the rotor punching sheet is larger than the distance from the lightening holes 4 to the circle center of the rotor punching sheet.

In practical use, when the rotor sheet with high rotation speed is in interference fit with the rotating shaft, the larger interference magnitude of the rotor sheet has larger negative influence on the stress at the second middle magnetic separation bridge 32. This embodiment, in particular with the relief slots 5 arranged above between adjacent lightening holes 4, makes it possible to reduce this negative effect and avoid damage. The existence of the unloading groove 5 can further condition the deformation nonuniformity of the two ends of the second outer magnetic isolation bridge 33 and reduce the peak stress of the second middle magnetic isolation bridge 32. The plurality of lightening holes 4 and unloading grooves 5 which are staggered along the circumferential direction of the rotor sheet enable the rotor sheet to be lightened, and simultaneously can unload stress concentrated on the second middle magnetic isolation bridge 32.

In the embodiment, because the distance between the unloading groove 5 and the lightening hole 4 is short, in order to avoid the occurrence of penetrating fracture of the unloading groove 5 and the lightening hole 4 in the use process, the ratio of the distances from the centers of the unloading groove 5 and the lightening hole 4 to the circle center of the rotor sheet is particularly set to be 1.3.

In the embodiment, the lightening holes 4 are elliptical holes, the long axes of the elliptical holes are perpendicular to the radial direction, and the ratio of the distance from the centers of the lightening holes 4 to the circle center of the rotor sheet to the radius of the rotor sheet is 0.5.

The elliptical holes can be used for favorably relieving the stress concentration effect at the positions of the holes. The position coordinate parameters of the elliptical holes are used as variables, the stress of the second middle magnetic isolation bridge 32 is used as a target, parameter optimization is carried out, and the result shows that the ratio of the distance from the center of the lightening hole 4 to the center of the punching sheet to the excircle radius of the punching sheet is 0.5, so that the strength problem of the positions of the lightening hole 4 and the second middle magnetic isolation bridge 32 can be well balanced.

In this embodiment, the near-axis hole end of the second magnet slot 31 is formed by tangency of multiple arc lines 6, so that the width of the second middle magnetism isolating bridge 32 is widened from the middle to the two ends. As shown in fig. 5, the second middle magnetic isolation bridge 32 is different from the conventional design in that the width of the magnetic bridge is variable, the middle is small, and the two ends are large, and approximate to an elliptical arc. According to the traditional design, the wider magnetic isolation bridge with the same width can enhance the strength of the magnetic isolation bridge, but the leakage magnetic flux can be increased, and the performance of the motor is reduced. And the design that adopts the width variation, the big part in both ends can strengthen magnetic bridge intensity, and the middle part can reduce the magnetic leakage flux, can accomplish to compromise intensity and performance index simultaneously.

As shown in fig. 5, the circular arc lines 6 include a first circular arc line 61 with a radius R1, a second circular arc line 62 with a radius R2, a third circular arc line 63 with a radius R3, and a fourth circular arc line 64 with a radius R4, where R1 ═ R3 ═ 3mm, R2 ═ 2R1, and the size of R4 is determined by the minimum distance S between the second middle magnetic bridge 32 and the unloading groove 5, and S ═ 3.5mm is satisfied.

Fig. 6 is a stress comparison graph of the rotor sheet of the present embodiment and the rotor sheet of the second middle flux-separating bridge with the same width, the maximum stress of the second middle flux-separating bridge 32 of the present embodiment is 376.26MPa (see fig. 6a), and the maximum stress of the flux-separating bridge design with the same width is 435.31MPa (see fig. 6b), compared with the stress of the present embodiment reduced by 13.5%.

In this embodiment, since the second middle flux-insulated bridge 32 has a larger size, in order to ensure the leakage flux of the entire rotor, it is desirable to set the ratio of the width of the second middle flux-insulated bridge 32 to the width of the first middle flux-insulated bridge 22 to be 2, so as to control the leakage flux of the entire rotor structure.

In order to reduce the leakage flux of the rotor system, the ratio of the minimum width of the first outer flux-insulated bridge 23 to the width of the second outer flux-insulated bridge 33 is controlled to be 0.95, while taking into consideration the strength.

As shown in fig. 7, in this embodiment, the far-axis hole end of the second magnet slot 31 is an arc-shaped edge 71, the arc-shaped edge 71 is formed by multiple arcs in a tangent manner, the arc-shaped edge 71 is connected with the long edge 311 of the second magnet slot 31 located inside the V-shape through a transition arc 72, an included angle θ exists between a tangent of the transition arc 72 and an extension line of the long edge 311, and the size of the included angle is determined by a performance simulation result. By forming a certain included angle θ, the bearing width of the second outer magnetic isolation bridge 33 can be effectively increased, the deformation nonuniformity in the whole width range is further reduced, and further, the peak stress of the second outer magnetic isolation bridge 33 is reduced, as shown in fig. 8a, the peak stress of the second outer magnetic isolation bridge 33 in this embodiment is 383.67MPa, as shown in fig. 8b, the peak stress of the second outer magnetic isolation bridge without an included angle is 432.85MPa, and the peak stress of the second outer magnetic isolation bridge in this embodiment is reduced by 11.4%.

In this embodiment, a self-buckling point 8 is arranged between every two adjacent second V-shaped grooves 3, a self-buckling point 8 is arranged between each first V-shaped groove 2 and each second V-shaped groove 3, the self-buckling points 8 are uniformly arranged along the circumferential direction of the rotor sheet, and the ratio of the distance from the center of each self-buckling point 8 to the center of the rotor sheet to the radius of the rotor sheet is 0.8.

The two rotor punching sheets can be connected through the self-buckling point 8, bear certain centrifugal force, enhance the overall strength of the rotor punching sheets and avoid the magnetic separation bridge part from being broken due to overlarge stress.

In this embodiment, the ratio of the V-shaped angles of the first V-shaped groove 2 and the second V-shaped groove 3 is 1.35; the ratio of the areas of the magnet placing areas of the first magnet groove 2 and the second magnet groove 3 is 0.3; the sum of the areas of the lightening holes 4 and the unloading grooves 5 accounts for 19.37 percent of the total area of the rotor punching sheet.

A high-speed permanent magnet synchronous motor comprises a rotating shaft 9 and the rotor punching sheet, wherein the rotor punching sheet is matched with the rotating shaft 9 through a shaft hole 1.

In this embodiment, the rotating shaft 9 is a hollow rotating shaft, the hollow ratio is 0.5, that is, the ratio of the inner diameter of the rotating shaft to the outer diameter of the rotating shaft is 0.5, and the rotating shaft 9 is in interference fit with the rotor sheet through the shaft hole 1.

The high-speed permanent magnet synchronous motor of the embodiment is provided with the rotor punching sheet of the embodiment, so that the high-speed permanent magnet synchronous motor also has the advantages of the rotor punching sheet.

The above are only preferred embodiments of the present invention, and the scope of protection of the present invention is not limited to the above examples, and the technical features related to the above described embodiments of the present invention may be combined with each other as long as they do not conflict with each other, and all technical solutions belonging to the idea of the present invention belong to the scope of protection of the present invention. It should be noted that modifications and embellishments within the scope of the utility model may be made by those skilled in the art without departing from the principle of the utility model.

Claims (11)

1. A rotor punching sheet is characterized in that a plurality of double-V-shaped magnet grooves are uniformly formed in the rotor punching sheet along the circumferential direction, each double-V-shaped magnet groove comprises a first V-shaped groove (2) and a second V-shaped groove (3) which are distributed from outside to inside along the radial direction, a V-shaped opening of each second V-shaped groove (3) faces outwards along the radial direction, a second middle magnetic isolation bridge (32) is arranged at a V-shaped tip part, a second outer magnetic isolation bridge (33) is arranged at a V-shaped tail part, a plurality of unloading grooves (5) which are uniformly arranged along the circumferential direction are further formed in the rotor punching sheet, the unloading grooves (5) are located between the double-V-shaped magnet grooves and the shaft hole (1) and are located on the symmetry line of two adjacent double-V-shaped magnet grooves, and the unloading grooves (5) are formed by multiple sections of arcs in a tangent mode; the ratio of the radial width M1 and the circumferential width M2 of the unloading groove (5) is 0.5-0.6, and the ratio of the radial width M1 of the unloading groove (5) to the radius of the rotor punching sheet is 0.14-0.16.

2. The rotor punching sheet according to claim 1, wherein a plurality of weight-reducing holes (4) are further formed in the rotor punching sheet and are evenly distributed along the circumferential direction, the weight-reducing holes (4) are located on a symmetrical center line of the double-V-shaped magnet slots, and the distance from the unloading slot (5) to the center of the rotor punching sheet is greater than the distance from the weight-reducing holes (4) to the center of the rotor punching sheet.

3. The rotor punching sheet according to claim 2, wherein the ratio of the distances from the centers of the unloading slots (5) and the lightening holes (4) to the circle center of the rotor punching sheet is 1.25-1.35;

and/or the lightening holes (4) are elliptical holes, the long axes of the elliptical holes are perpendicular to the radial direction, and the ratio of the distance from the centers of the lightening holes (4) to the circle center of the rotor sheet to the radius of the rotor sheet is 0.5-0.55.

4. The rotor punching sheet according to claim 2, wherein the second V-shaped groove (3) comprises two second magnet grooves (31) which are arranged in a V shape and are radially symmetrical, a second middle magnetic isolation bridge (32) is formed between the near-axis hole ends of the two second magnet grooves (31), the far-axis hole ends of the two second magnet grooves (31) and the periphery of the rotor punching sheet respectively form a second outer magnetic isolation bridge (33), and the near-axis hole ends of the second magnet grooves (31) are formed by tangency of multiple sections of circular arc lines (6), so that the width of the second middle magnetic isolation bridge (32) is widened from the middle to the two ends.

5. The rotor punching sheet according to claim 4, wherein the circular arc lines (6) comprise a first circular arc line (61) with a radius of R1, a second circular arc line (62) with a radius of R2, a third circular arc line (63) with a radius of R3 and a fourth circular arc line (64) with a radius of R4, wherein R1R 3 is larger than or equal to 3mm, R2R 1 is larger than or equal to 2R1, and the size of R4 is determined by the minimum distance S between the second middle magnetic isolation bridge (32) and the unloading groove (5), and S is larger than or equal to 3.5 mm.

6. The rotor punching sheet according to claim 4, wherein the far axial hole end of the second magnet groove (31) is an arc-shaped edge (71), the arc-shaped edge (71) is formed by multiple sections of arcs in a tangent mode, the arc-shaped edge (71) is connected with a long edge (311) of the second magnet groove (31) located on the inner side of the V shape through a transition arc (72), and an included angle exists between the tangent line of the transition arc (72) and the extension line of the long edge (311).

7. The rotor punching sheet according to any one of claims 1 to 6, wherein a self-buckling point (8) is arranged between every two adjacent second V-shaped grooves (3), a self-buckling point (8) is arranged between each first V-shaped groove (2) and each second V-shaped groove (3), the self-buckling points (8) are uniformly arranged along the circumferential direction of the rotor punching sheet, and the ratio of the distance from the center of each self-buckling point (8) to the center of the rotor punching sheet to the radius of the rotor punching sheet is 0.80-0.84.

8. The rotor punching sheet according to any one of claims 1 to 6, wherein the first V-shaped groove (2) comprises two first magnet grooves (21) which are arranged in a V shape and are radially symmetrical, the opening of the V shape faces outwards in the radial direction, a first middle magnetic isolation bridge (22) is formed between the near axial hole ends of the two first magnet grooves (21), the far axial hole ends of the two first magnet grooves (21) and the periphery of the rotor punching sheet respectively form a first outer magnetic isolation bridge (23), and the ratio of the minimum width of the second middle magnetic isolation bridge (32) to the width of the first middle magnetic isolation bridge (22) is 1.5-3.0.

9. The rotor sheet according to any one of claims 2 to 6, wherein the ratio of the V-shaped angles of the first V-shaped groove (2) and the second V-shaped groove (3) is 1.33-1.43; the ratio of the areas of the first V-shaped groove (2) and the second V-shaped groove (3) for placing the magnets is 0.27-0.32; the sum of the areas of the lightening holes (4) and the unloading grooves (5) accounts for 19.37 percent of the total area of the rotor punching sheet.

10. A high-speed permanent magnet synchronous motor, which is characterized by comprising a rotating shaft (9) and the rotor sheet as claimed in any one of claims 1 to 9.

11. The high-speed permanent magnet synchronous motor according to claim 10, wherein the rotating shaft (9) is in interference fit with the rotor sheet; and/or, the rotating shaft (9) is a hollow rotating shaft, and the ratio of the inner diameter of the rotating shaft (9) to the outer diameter of the rotating shaft (9) is 0.5-0.6.

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