CN115776184A - Rotor punching sheet, rotor of motor and motor - Google Patents

Abstract

The application relates to the technical field of motors and discloses a rotor punching sheet, a rotor of a motor and the motor. Wherein rotor punching includes: the magnetic steel slots are of a symmetrical structure and are uniformly distributed along the circumferential direction of the rotor punching sheet; the slit group is arranged on one side of the magnetic steel groove, which is away from the center of the rotor punching sheet, the slit group and the magnetic steel groove are in one-to-one correspondence, and the slit group comprises a plurality of slits communicated with the magnetic steel groove. Compared with the prior art, the permanent magnet in the magnetic steel groove can be directly radiated through the plurality of slits, on the basis of reducing the electromagnetic force, the radiating channel is added, and the uniformity of heat radiation is further improved because the plurality of slits are symmetrically distributed relative to the axial symmetry line of the magnetic steel groove.

Description

Rotor punching sheet, rotor of motor and motor

Technical Field

The application relates to the technical field of motors, in particular to a rotor punching sheet, a rotor of a motor and the motor.

Background

The core part of motor is the rotor, and the rotor comprises a plurality of range upon range of rotor punching pieces, can set up a plurality of magnetic steel grooves on the rotor punching piece for hold the permanent magnet, for arrangement magnetic beam improves the vibration, can set up a plurality of slits in one side in the magnetic steel groove more, slit and magnetic steel groove independent set in the current rotor punching piece, under rotor high-speed operation, the vibration noise of motor is big, and the magnetic steel heat is concentrated, leads to the permanent magnet demagnetization easily, and the reliability of rotor is relatively poor.

Disclosure of Invention

In order to solve the technical problems of large noise and heat concentration of the rotor, the main aim of the application is to provide the rotor punching sheet for reducing the noise and avoiding the heat concentration, the motor and the rotor thereof.

In order to achieve the purpose of the invention, the following technical scheme is adopted in the application:

according to an aspect of the application, a rotor sheet is provided, which comprises:

the magnetic steel slots are of an axisymmetric structure and are uniformly distributed along the circumferential direction of the rotor punching sheet;

the magnetic steel slots are arranged on the side, away from the center of the rotor punching sheet, of the magnetic steel slots, the slit groups correspond to the magnetic steel slots one to one, and each slit group comprises a plurality of slits communicated with the magnetic steel slots.

According to an embodiment of the application, the center line of each slit and the axial symmetry line of the magnetic steel slot have a first intersection point, and the first intersection point is located on the outer side of the rotor punching sheet.

According to an embodiment of the application, each slit group comprises two pairs of slits which are symmetrical about the central line of the magnetic steel slot, and along with the position of each slit is gradually far away from the central line of the magnetic steel slot, the first intersection point formed by the intersection of the central line of the slit and the axial symmetry line of the magnetic steel slot is gradually close to the center of the rotor punching sheet.

According to an embodiment of the application, each slit group comprises at least three pairs of slits symmetrical about a central line of the magnetic steel slot, and along with the position of the slit is gradually far away from the central line of the magnetic steel slot, the first intersection point formed by intersection of the central line of the slit and an axial symmetry line of the magnetic steel slot is gradually far away from the center of the rotor sheet and then gradually approaches to the center of the rotor sheet.

According to an embodiment of the application, wherein including being located in a plurality of slits in the slit group the third slit of magnetic steel groove tip, the third slit includes first extension and the second extension of intercommunication, first extension is located the magnetic steel groove deviates from one side at rotor punching center, the second extension is located the magnetic steel groove is close to one side at rotor punching center, the central line of first extension with the axial symmetry line in magnetic steel groove has first nodical, the central line of second extension with the axial symmetry line in magnetic steel groove has the second nodical, the second nodical is located the outside of rotor punching.

According to an embodiment of the application, a distance between a first intersection point corresponding to the first extending portion and the center of the rotor sheet is D1, a distance between a second intersection point corresponding to the second extending portion and the center of the rotor sheet is D2, wherein D1 is less than D2.

According to an embodiment of the present application, the length of the slit in the extending direction of the slit is L1, the width of the slit perpendicular to the extending direction of the slit is W1, and the magnetic steel slot width is W2, wherein L1 > W2 > W1.

According to an embodiment of the present application, the cross section of the magnetic steel slot is in a straight line shape or a V shape.

According to an embodiment of the application, still include a plurality of through-holes wherein, it is a plurality of the through-hole interval set up in the magnet steel slot is close to one side of the center of rotor punching.

According to another aspect of the application, a rotor of an electric machine is provided, and the rotor punching sheet is included.

According to another aspect of the present application, there is provided an electric machine comprising a rotor of the electric machine described above.

According to the technical scheme, the rotor of the rotor punching sheet and the motor has the advantages and positive effects that:

the circumference evenly distributed of rotor punching is followed to a plurality of magnetic steel grooves, a plurality of slit groups set up in the magnetic steel groove and deviate from one side at the center of rotor punching, slit group and magnetic steel groove one-to-one, and then improve the homogeneity that the heat effuses, because, slit group is including a plurality of slits with the magnetic steel groove intercommunication, the direct heat dissipation that dispels of permanent magnet of a plurality of slits of accessible to the magnetic steel inslot, on the basis that reduces the electromagnetic force, increase the heat dissipation passageway, and because the axial symmetry line symmetric distribution in the relative magnetic steel groove of a plurality of slits, further improve the homogeneity that the heat effuses.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and together with the description, serve to explain the principles of the invention.

In order to more clearly illustrate the embodiments or technical solutions in the prior art of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious for those skilled in the art to obtain other drawings without inventive labor.

Fig. 1 is a schematic overall structure diagram of a rotor sheet according to an embodiment of the present disclosure;

fig. 2 is an enlarged structural schematic diagram of a position a in a rotor sheet provided in an embodiment of the present application;

fig. 3 is another schematic overall structure diagram of a rotor sheet according to an embodiment of the present disclosure;

fig. 4 is an enlarged structural schematic diagram of a position B in a rotor sheet according to an embodiment of the present application;

fig. 5 is a schematic partial structure diagram of a position B in a rotor sheet according to an embodiment of the present application;

fig. 6 is a structural schematic diagram of a distribution state of first intersections and second intersections in a rotor sheet according to an embodiment of the present application.

Wherein:

100. punching a rotor sheet; 110. an edge line; 120. the center of the rotor sheet;

10. a magnetic steel groove; 11. an axial symmetry line of the magnetic steel slot;

20. a slit group; 21. a slit; 211. a centerline of the slit; 212. a first slit; 213. a second slit; 214. a third slit; 241. a first extension portion; 242. a second extension portion;

30. a first intersection point; 40. a second intersection point; 50. and a through hole.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

The core part of motor is the rotor, the rotor comprises a plurality of range upon range of rotor punching pieces, can set up a plurality of magnetic steel grooves on the rotor punching piece, be used for holding the permanent magnet, improve the vibration for arrangement magnetic beam, many can set up a plurality of slits in one side of magnetic steel groove, slit and magnetic steel groove independent settings in the current rotor punching piece, slit and magnetic steel groove do not communicate each other, so under rotor high-speed operation, the vibration noise of motor is big, the heat that the permanent magnet in the rotor produced concentrates on the magnetic steel inslot easily, this leads to the permanent magnet demagnetization easily, cause the relatively poor reliability of rotor. For solving the big, heat of rotor noise and concentrating the technical problem, according to an aspect of this application, provide a rotor punching, include:

the magnetic steel slots 10 are of a symmetrical structure, and the magnetic steel slots 10 are uniformly distributed along the circumferential direction of the rotor sheet 100;

the plurality of the slit groups 20 are arranged on the side, away from the center 120 of the rotor sheet 100, of the magnetic steel slot 10, the slit groups 20 correspond to the magnetic steel slots 10 one to one, and each slit group 20 comprises a plurality of slits 21 communicated with the magnetic steel slot 10.

As an example, referring to fig. 1 to 6, after the plurality of magnetic steel slots 10 are uniformly distributed at equal angles along the circumferential direction of the rotor sheet 100, and the slit groups 20 correspond to the magnetic steel slots 10 one by one, on one hand, the magnetic bundles of the permanent magnets in the magnetic steel slots 10 are arranged through the slit groups 20 to reduce the electromagnetic force, and on the other hand, each magnetic steel slot 10 can be communicated with the magnetic steel slots 10 through the plurality of slits 21 in the slit group 20, so that the heat dissipation channel area of the magnetic steel slot 10 is increased, the heat dissipation efficiency is improved, and the reliability of the performance of the rotor in the use process is improved.

As an example, the end portions of the plurality of slits 21 are located at a side close to the edge line 110 of the rotor sheet 100, that is, the slits 21 are formed in the rotor sheet 100, so that the vibration between the slits 21 and the air outside the rotor sheet 100 is reduced, and the noise generated during the operation of the rotor sheet 100 is further reduced on the basis of improving the stability of the mechanical structure of the rotor sheet 100.

According to an embodiment of the present application, the center line of each of the slits 21 and the axial symmetry line of the magnetic steel slot 10 have a first intersection point 30, and the first intersection point 30 is located outside the rotor sheet 100.

The center line of the slit 21 is: a line extending in the extending direction of the slit 21 between the two extending sides of the slit 21 and having the same distance between points opposed to the two extending sides of the slit 21. The axial symmetry line of the magnetic steel slots 10 is a symmetrical center line of the magnetic steel slots 10, and it should be further noted that, since the plurality of magnetic steel slots 10 are uniformly distributed at equal angles along the circumferential direction of the rotor sheet 100, the symmetrical center line of the magnetic steel slots 10 passes through the center of the rotor sheet 100, that is, the axial symmetry line of the magnetic steel slots 10 is on a straight line where the diameter of the rotor sheet 100 is located.

As an example, referring to fig. 2, when the center line of each slit 21 and the axial symmetry line of the magnetic steel slot 10 have a first intersection point 30, and the first intersection point 30 is located outside the edge line 110, the opening angle of the included angle between the extension direction of each slit 21 and the extension direction of the magnetic steel slot 10 can be controlled within a relatively large range, so that the opened slits 21 can adjust the flow of the magnetic field on the stator and the rotor, dredge the magnetic circuit reasonably, reduce the low-order harmonics of the air gap flux density and further reduce the noise, and since the slits 21 are communicated with the magnetic steel slot 10, the low-order harmonics of the air gap flux density can be further reduced, and the electromagnetic force causing the noise can be further reduced, thereby reducing the noise fundamentally. As an example, the magnetic steel slot 10 has a straight cross section.

In the prior art, a slit is formed between a magnetic steel slot and the outer side edge of a rotor to reduce electromagnetic force, and because the slit is not communicated with the magnetic steel slot, only higher harmonics are reduced essentially, and some lower harmonics flow through a channel between the slit and the magnetic steel slot and enter air gaps in a large quantity, so that larger lower harmonics are caused. Some conventional slot-pole matched machines, such as the most commonly used 9-slot 6-pole machine, the minimum non-zero order electromagnetic force (6 times the frequency) is due to the low order harmonics of the magnetic field, which are thus the largest contributors to noise and vibration. Therefore, by adopting the technical scheme, the first intersection point 30 is controlled to be positioned at the outer side of the edge line 110, and the slit 21 is communicated with the magnetic steel slot 10, so that the minimum non-zero electromagnetic force caused by rich low-order harmonics can be greatly reduced, and the electromagnetic noise is greatly weakened.

According to an embodiment of the present application, each slit group 20 includes two pairs of slits 21 symmetrical with respect to the axial symmetry line of the magnetic steel slot 10, and as the position of the slit gradually gets away from the axial symmetry line of the magnetic steel slot 10, the first intersection point formed by the intersection of the central line of the slit and the axial symmetry line of the magnetic steel slot gradually gets closer to the center of the rotor sheet 100.

Referring to fig. 2, two slits 21 are sequentially arranged at intervals along the direction of the axial symmetry line far away from the magnetic steel slot 10 at one side of the axial symmetry line of the magnetic steel slot 10, one of the slits 21 is located at the end of the magnetic induction slot (equivalent to the first extension portion 241), so that the distance between the first intersection point 30 and the center 120 of the rotor sheet 100 is sequentially reduced along the direction of the axial symmetry line far away from the magnetic steel slot 10, the included angle between the center line of the slit 21 closer to the magnetic steel slot 10 and the center line of the magnetic steel slot 10 is gradually increased, and then the magnetic flux flow direction is guided by the slits 21, so that the magnetic field generated by the permanent magnet in the magnetic steel slot 10 can be intensively and slowly guided to the air gap, and the electromagnetic noise is effectively weakened on the basis of improving the area of the heat dissipation channel.

According to an embodiment of the present application, each of the slit groups 20 includes at least three pairs of slits 21 symmetrical with respect to an axial symmetry line of the magnetic steel slot 10, and as the position of the slit gradually gets away from the axial symmetry line of the magnetic steel slot 10, the first intersection point formed by the intersection of the central line of the slit and the axial symmetry line of the magnetic steel slot gradually gets away from the center of the rotor sheet 100, and then gradually gets close to the center 120 of the rotor sheet.

As an example, the plurality of slits 21 in each slit group 20 include a pair of first slits 212 and at least two pairs of second slits 213, and the plurality of second slits 213 are spaced at two sides of the first slits 212 on one side of the axial symmetry line of the magnetic steel slot 10, wherein:

from the axial symmetry line of the magnetic steel slot 10 to the direction of the first slit 212, the distance between the first intersection points 30 corresponding to the first slit 212 and the second slits 213 and the rotor sheet center 120 gradually increases;

in a direction from the first slit 212 to the edge line 110 of the rotor sheet 100, distances between the first intersections 30 corresponding to the first slit 212 and the second slits 213 and the rotor sheet center 120 gradually decrease.

As an example, referring to fig. 3, two slits 21 are sequentially disposed at intervals along the direction of the axial symmetry line far away from the magnetic steel slot 10 on one side of the axial symmetry line of the magnetic steel slot 10, so that the distance between the two first intersection points 30 formed by corresponding two slits 21 and the center of the rotor sheet 100 is sequentially increased along the direction of the axial symmetry line far away from the magnetic steel slot 10, the included angle between the center line of the slit 21 closer to the magnetic steel slot 10 and the center line of the magnetic steel slot 10 is gradually decreased, and further, the magnetic flux flow direction is guided by the slits 21, so that the magnetic field generated by the permanent magnet in the magnetic steel slot 10 can be slowly and intensively guided to the air gap, and the electromagnetic noise is effectively reduced on the basis of increasing the area of the heat dissipation channel.

As an example, referring to fig. 3, two slits 21 are sequentially provided at intervals along the direction of the axial symmetry line far from the magnetic steel slot 10 on one side of the axial symmetry line of the magnetic steel slot 10, in an embodiment, the two slits 21 may be provided between the center line of the magnetic steel slot 10 and the end of the magnetic steel slot 10, in which case, the slit 21 near the center line of the magnetic steel slot 10 corresponds to the second slit 213, and the slit 21 near the end of the magnetic steel slot 10 corresponds to the first slit 212.

As an example, referring to fig. 3-5, three slits 21 are sequentially arranged at intervals along the direction of the axial symmetry line far away from the magnetic steel slot 10 on one side of the axial symmetry line of the magnetic steel slot 10, in an embodiment, at this time, the slit 21 close to the center line of the magnetic steel slot 10 corresponds to a second slit 213, the slit 21 in the middle corresponds to a first slit 212, and the distance between the first intersection points 30 corresponding to the first slit 212 and the second slits 213 and the rotor punching center 120 gradually increases from the axial symmetry line of the magnetic steel slot 10 to the direction of the first slit 212; furthermore, the included angle between the center line of the slit 21 near the middle of the permanent magnet, that is, the center line from the first slit 212 to the second slit 213 in the center line of the magnetic steel slot 10, and the center line of the magnetic steel slot 10 gradually decreases;

as an example, referring to fig. 3-5, three slits 21 are sequentially provided at intervals along the axial symmetry line direction away from the magnetic steel slot 10 on one side of the center line of the magnetic steel slot 10, in an embodiment, the slit 21 (not shown) from the center line of the first slit 212 to the end close to the magnetic steel slot 10 is the second slit 213, and the slit 21 at the end of the magnetic induction slot is the second slit 213, at this time, the middle slit 21 is equivalent to the first slit 212, the slit 21 at the end of the magnetic steel slot 10 is equivalent to the third slit 214, the distance between the first intersection points 30 corresponding to the first slits 212 and the second slits 213 and the rotor center 120 is gradually reduced from the first slit 212 to the edge line 110 of the rotor sheet 100, and further, the center line of the slits 21 at both ends of the permanent magnet embedded in the magnetic steel slot 10, that is the center line of the second slit 213 (equivalent to the first extension 241 in the figure) close to the end of the magnetic steel slot 10, and the magnetic field is gradually and more effectively guided to flow more reasonably.

According to an embodiment of the present application, wherein including being located in a plurality of slots 21 in the slot group 20 the third slot 214 of magnetic steel slot 10 tip, third slot 214 includes first extension 241 and the second extension 242 of intercommunication, first extension 241 is located magnetic steel slot 10 deviates from one side at rotor punching piece 100 center, second extension 242 is located magnetic steel slot 10 is close to one side at rotor punching piece 100 center, the central line of first extension 241 with the axial symmetry line of magnetic steel slot 10 has first intersect 30, the central line of second extension 242 with the axial symmetry line of magnetic steel slot 10 has second intersect 40, second intersect 40 is located the outside of rotor punching piece 100.

As an example, referring to fig. 3 to fig. 5, on the basis of ensuring the stability of the mechanical structure of the rotor sheet 100, the second extending portion 242 reduces the vibration, and can further improve the heat dissipation at the center 120 of the rotor sheet. As an example, the magnetic steel slot 10 has a V-shaped cross section.

As an example, referring to fig. 3-5, three slits 21 are sequentially disposed at intervals along the axial symmetry direction away from the magnetic steel slot 10 on one side of the center line of the magnetic steel slot 10, in an embodiment, the first extending portion 241 located at the end of the magnetic induction slot is a second slit 213, at this time, the middle slit 21 is equivalent to the first slit 212, and the distance between the first intersection 30 of the first slit 212 and the first extending portion 241 and the center 120 of the rotor sheet is gradually reduced from the first slit 212 to the edge line 110 of the rotor sheet 100, and further, the included angle between the center line of the slit 21 at both ends of the permanent magnet embedded in the magnetic steel slot 10, that is, the center line of the first extending portion 241 and the center line of the magnetic steel slot 10 is gradually increased, so that the magnetic field can be guided to flow more reasonably, and the magnetic field can be guided to the air gap more effectively and slowly and intensively.

According to an embodiment of the present application, a distance between the first intersection point 30 corresponding to the first extension portion 241 and the rotor punching center 120 is D1, and a distance between the second intersection point 40 corresponding to the second extension portion 242 and the rotor punching center 120 is D2, where D1 < D2.

For example, referring to fig. 6, by setting the distance between the second intersection point 40 corresponding to the second extending portion 242 and the rotor sheet center 120 to be D2, controlling D1 to be less than D2, and further controlling the included angle between the center line of the first extending portion 241 and the center line of the magnetic steel slot 10 to be larger than the included angle between the center line of the second extending portion 242 and the center line of the magnetic steel slot 10, the magnetic field near the center of the rotor sheet 100 can be effectively guided to the air gap in a slowly concentrated manner, and the operating noise can be further reduced.

According to an embodiment of the present application, the length of the slit 21 in the extending direction thereof is L1, the width of the slit 21 perpendicular to the extending direction thereof is W1, and the width of the magnetic steel slot 10 is W2, wherein L1 > W2 > W1.

Referring to fig. 5, when L1 > W2 > W1 is satisfied between the width of the slit 21 for guiding the flow of the magnetic flux and the width of the permanent magnet inserted into the magnetic steel slot 10 (corresponding to the width W2 of the magnetic steel slot 10), the guiding of the flow of the magnetic flux by the slit 21 can be further improved.

According to an embodiment of the present application, the rotor punching sheet further includes a plurality of through holes 50, and the through holes 50 are disposed at intervals on one side of the magnetic steel slot 10 close to the rotor punching sheet center 120.

Referring to fig. 1 to 5, in order to reduce high-temperature demagnetization of the permanent magnet caused by high-speed heat generation, a plurality of through holes 50 are formed at the lower end of the magnetic steel slot 10, and the through holes 50 are adjacent to the permanent magnet, so that heat on the permanent magnet can be effectively taken away. For uniform heat conduction, the through holes 50 are arranged in parallel with the magnetic steel grooves 10.

Preferably, the distance between the through hole 50 and the magnetic steel slot 10 is smaller than the width W2 of the magnetic steel slot 10, so as to be adjacent to the magnetic steel slot 10 and achieve a better heat conduction effect.

Preferably, in order not to affect the magnetic circuit, the distance between adjacent through holes 50 should be greater than the distance between the through holes 50 and the magnetic steel slot 10.

By way of example, with the rotor structure according to the present invention, the slits 21 communicating with the magnetic steel slots 10 and the holes around the magnetic steel slots 10 are provided, so that the electromagnetic force can be significantly reduced, and the heat dissipation channels of the permanent magnets can be increased to improve the reliability. The scheme provided by the application comprises the following steps:

1. at least one pair of slits 21 which are symmetrical about the center line of the magnetic steel slot 10 and are communicated with the magnetic steel slot 10 are arranged on the area formed by the magnetic steel slot 10 and the outer side edge of the rotor. The slit 21 is slender, and the intersection point of the equidistant line of two sides along the radial direction of the rotor and the central line of the magnetic steel slot 10 is positioned at the outer side of the circular arc of the rotor.

2. The width of the radial side of the slit 21 (corresponding to L1) is greater than the width of the circumferential side (corresponding to W1), and the width of the magnetic steel slot 10 (corresponding to W2) is between the radial width and the circumferential width of the slit 21.

3. The distance from the intersection point (equivalent to the first intersection point 30) of the slit 21 and the central line of the magnetic steel slot 10 to the center of the rotor shaft (equivalent to the center 120 of the rotor sheet) is increased and then decreased along the direction close to the two ends of the magnetic steel slot 10 (refer to fig. 3-5).

4. Be located the region of the inboard edge formation of magnet steel slot 10 and rotor, have a plurality of through-holes 50 of arranging with magnet steel slot 10 parallel, through-hole 50 form on the rotor with magnet steel slot 10 the maximum distance be less than magnet steel slot 10's width, adjacent through-hole 50 minimum distance that forms on the rotor be greater than through-hole 50 and the minimum distance that magnet steel slot 10 formed on the rotor improve the radiating effect through-hole 50.

5. The two ends of the magnetic steel slot 10 are provided with a protruding part (equivalent to a second extending part) communicated with the magnetic steel slot 10, the protruding part extends towards the inside of the rotor, and the central line of the second extending part and the central line of the magnetic steel form an intersection point (equivalent to a second intersection point 40) positioned outside the rotor.

The general operating range of the conventional compressor is 10-120HZ at present, larger vibration and noise can occur when the operating range exceeds 120HZ, the interior of the motor generates heat seriously at high rotating speed, the high-temperature irreversible demagnetization of a permanent magnet of the permanent magnet motor is easy to cause, and the reliability is poor. The compressor is applied to the compressor which runs over 120HZ, particularly a high-speed motor, and the main solution to noise and heat generation is the research focus.

The invention can synchronously solve the problems of outstanding electromagnetic noise and vibration of the motor and large heat productivity of the motor when the motor of the compressor runs at high speed. In particular, the slit 21 provided by the invention can adjust the circulation of a magnetic field on the stator and the rotor, reasonably dredge a magnetic circuit, reduce low-order harmonic waves of air gap flux density, and greatly reduce electromagnetic force causing noise, thereby fundamentally reducing the noise.

Because the prior proposal is that a slit is arranged between a magnetic steel slot and the outer side edge of a rotor to reduce the electromagnetic force, because the slit is not communicated with the magnetic steel slot, the reduction is essentially only higher harmonics, and some lower harmonics flow through a channel between the slit and the magnetic steel slot and enter air gaps in large quantity, thereby causing larger lower harmonics. Some conventional slot pole mating machines, such as the most commonly used 9 slot 6 pole machine, the minimum non-zero order electromagnetic force (6 times the frequency) is due to the low order harmonics of the magnetic field and is the largest source of noise and vibration. The technology of the invention can greatly reduce the minimum non-zero electromagnetic force caused by the abundance of low-order harmonic waves, thereby greatly weakening the electromagnetic noise.

The scheme of the invention comprises at least one pair of slits 21 communicated with the magnetic steel slot 10, wherein the slits 21 and the central line of the magnetic steel slot 10 have intersection points, in order to reasonably guide the circulation of a magnetic field, the slits 21 are slender as a whole, in order to slowly guide the magnetic field to an air gap in a concentrated manner, the included angle between the slits 21 at the two end accessories of the permanent magnet embedded into the magnetic steel slot 10 and the central line of the magnetic steel slot 10 is larger, and the included angle between the slits 21 near the middle of the permanent magnet and the central line of the magnetic steel slot 10 is smaller. Therefore, the optimum solution exists for the included angle between the slits 21 and the center line of the magnetic steel slot 10, that is, the intersection point of the slits 21 and the center line of the magnetic steel slot 10 is located outside the rotor area, and the distance between the intersection point and the center of the rotor increases and then decreases in the direction from the center line of the magnetic steel slot 10 to the two ends of the magnetic steel slot 10.

Furthermore, the slit 21 for guiding the magnetic flux to flow and the permanent magnet embedded in the magnetic steel slot 10 satisfy a certain relationship, and the guiding work can be well completed, that is, the thickness of the permanent magnet (theoretically equal to the width W2 of the magnetic steel slot 10) should be between the circumferential width and the radial width of the slit 21.

Furthermore, in order to reduce the high-temperature demagnetization of the permanent magnet caused by the high-speed heating, a plurality of holes are formed in the lower end of the magnetic steel groove 10, and the holes are adjacent to the permanent magnet, so that the heat on the permanent magnet can be effectively taken away. For uniform heat conduction, the holes are arranged in parallel with the magnetic steel grooves 10.

Preferably, the gap is close to the magnetic steel slot 10, so that a better heat conduction effect is achieved, and the distance between the hollow hole and the magnetic steel slot 10 is smaller than the width of the magnetic steel slot 10.

Preferably, in order not to affect the magnetic circuit, the circumferential distance formed by the adjacent holes should be greater than the distance between the holes and the magnetic steel slot 10.

Further more preferably, in order to avoid high-temperature demagnetization of the permanent magnet at high speed, on one hand, the slits 21 and the holes communicated with the magnetic steel slot 10 need to be formed to serve as heat dissipation holes to cool the permanent magnet, and on the other hand, the slits 21 extending from the two ends of the magnetic steel slot 10 to the inside of the rotor need to be formed to improve the demagnetization resistance of the permanent magnet, because the demagnetization magnetic field circulates around the slits 21, the degree of the demagnetization magnetic field acting on the permanent magnet is reduced.

According to another aspect of the application, a rotor of an electric machine is provided, and the rotor punching sheet is included.

According to another aspect of the present application, there is provided an electric machine comprising a rotor of the above-described electric machine. It is noted that, in this document, relational terms such as "first" and "second," and the like, may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrases "comprising a," "8230," "8230," or "comprising" does not exclude the presence of additional like elements in a process, method, article, or apparatus that comprises the element.

The foregoing are merely exemplary embodiments of the present invention, which enable those skilled in the art to understand or practice the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (11)

1. A rotor punching sheet is characterized by comprising:

the rotor punching sheet comprises a plurality of magnetic steel grooves (10), wherein the magnetic steel grooves (10) are of an axisymmetric structure, and the magnetic steel grooves (10) are uniformly distributed along the circumferential direction of the rotor punching sheet (100);

the magnetic steel rotor punching sheet is characterized by comprising a plurality of slit groups (20), wherein the slit groups (20) are arranged on one side, deviating from the center of the rotor punching sheet (100), of the magnetic steel slot (10), the slit groups (20) correspond to the magnetic steel slot (10) one to one, and the slit groups (20) comprise a plurality of slits (21) communicated with the magnetic steel slot (10).

2. The rotor sheet according to claim 1, wherein the center line of each slit (21) and the axial symmetry line of the magnetic steel slot (10) have a first intersection point (30), and the first intersection point (30) is located on the outer side of the rotor sheet (100).

3. The rotor sheet according to claim 2, wherein each slot group (20) comprises two pairs of slots (21) which are symmetrical about the axial symmetry line of the magnetic steel slot (10), and the center of the first intersection point formed by the intersection of the center line of the slot and the axial symmetry line of the magnetic steel slot (10) is gradually close to the center of the rotor sheet (100) as the position of the slot is gradually far away from the axial symmetry line of the magnetic steel slot (10).

4. The rotor sheet according to claim 2, wherein each of the slit groups (20) includes at least three pairs of slits (21) symmetrical about an axial symmetry line of the magnetic steel slot (10), and as the position of the slits gradually gets away from the axial symmetry line of the magnetic steel slot (10), the first intersection point formed by the intersection of the center line of the slits and the axial symmetry line of the magnetic steel slot gradually gets away from the center of the rotor sheet (100) first and then gradually gets closer to the center of the rotor sheet.

5. The rotor punching sheet according to claim 2, wherein the plurality of slits (21) in the slit group (20) include a third slit (214) at an end of the magnetic steel slot (10), the third slit (214) includes a first extension portion (241) and a second extension portion (242) which are communicated with each other, the first extension portion (241) is located on a side of the magnetic steel slot (10) facing away from a center of the rotor punching sheet (100), the second extension portion (242) is located on a side of the magnetic steel slot (10) close to the center of the rotor punching sheet (100), a center line of the first extension portion (241) and an axial symmetry line of the magnetic steel slot (10) have the first intersection point (30), a center line of the second extension portion (242) and the axial symmetry line of the magnetic steel slot (10) have the second intersection point (40), and the second intersection point (40) is located on an outer side of the rotor punching sheet (100).

6. The rotor sheet according to claim 5, wherein a distance between a first intersection point (30) corresponding to the first extension (241) and the center (120) of the rotor sheet is D1, and a distance between a second intersection point (40) corresponding to the second extension (242) and the center (120) of the rotor sheet is D2, wherein D1 < D2.

7. The rotor sheet according to claim 1, wherein the length of the slit (21) in the extending direction thereof is L1, the width of the slit (21) perpendicular to the extending direction thereof is W1, the slot width of the magnetic steel slot (10) is W2, and L1 > W2 > W1.

8. The rotor sheet according to claim 1, wherein the cross section of the magnetic steel groove (10) is in a straight shape or a V shape.

9. The rotor sheet according to any one of claims 1 to 8, further comprising a plurality of through holes (50), wherein the plurality of through holes (50) are arranged at intervals on one side of the magnetic steel slot (10) close to the center (120) of the rotor sheet.

10. A rotor of an electrical machine, comprising a rotor blade as claimed in any one of claims 1 to 9.

11. An electrical machine comprising a rotor of the electrical machine of claim 10.

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