CN107437858B - Motor rotor punching sheet, motor rotor, motor and electric automobile - Google Patents

Abstract

The invention discloses a motor rotor punching sheet, a motor rotor, a motor and an electric automobile, wherein the motor rotor punching sheet comprises a punching sheet body (100), a magnetic steel groove (200) for inserting magnetic steel is formed in the punching sheet body, the magnetic steel groove is provided with a straight line section (201) and inclined angle sections (202) positioned on two sides of the straight line section along the surface direction of the punching sheet body, and a first side edge of each inclined angle section, which is far away from the rotation center of the punching sheet body, inclines outwards from the end part of the straight line section. Through set up the inclination section that leans out in straightway both sides, can provide the buffer that produces the micro-deformation for the magnet steel both ends in the magnet steel groove, thereby when the rotor rotates promptly, allow the magnet steel to produce the tensile stress in magnet steel inslot micro-deformation release magnet steel inside, promote the life-span of magnet steel then, be particularly useful for among the electric automobile use of the driving motor of hypervelocity work.

Description

Motor rotor punching sheet, motor rotor, motor and electric automobile

Technical Field

The invention relates to the field of motor parts, in particular to a motor rotor punching sheet, a motor rotor using the punching sheet, a motor using the motor rotor and an electric automobile using the motor.

Background

Motors are widely used in various fields as driving devices. With the recent rise of electric vehicles, the importance of the electric vehicle as a driving motor for driving the vehicle to travel is needless to say. As known, an electric motor mainly includes a housing, a stator, and a rotor. For example, in some prior arts, the housing is a cylinder with an opening at the front end, a stator is arranged in the housing, the stator includes a stator core and a core winding, and the rotor includes a rotating shaft, a permanent magnet and a rotor core; the rotor iron core is sleeved on the rotating shaft, and a plurality of permanent magnets are uniformly distributed on the periphery of the rotor iron core; the front end of the shell is provided with an end face, and the upper end of the shell is provided with a junction box for supplying power to the winding. Thereby realizing the rotation driving function of the motor. The driving motor of the electric vehicle usually needs large power and small volume, and how to solve the contradiction is also an important subject to be researched in the field.

Disclosure of Invention

The invention aims to provide a motor rotor punching sheet, a motor rotor using the motor rotor punching sheet, a motor using the motor rotor and an electric automobile using the motor.

In order to achieve the purpose, the invention provides a motor rotor punching sheet which comprises a punching sheet body, wherein a magnetic steel groove for inserting magnetic steel is formed in the punching sheet body, the magnetic steel groove is provided with a straight line section and inclination angle sections positioned on two sides of the straight line section along the surface direction of the punching sheet body, and a first side edge of the inclination angle section, which is far away from the rotation center of the punching sheet body, inclines outwards from the end part of the straight line section.

Optionally, two of the dip angle sections are symmetrically disposed about the center of the straight line section.

Optionally, the included angle between the first lateral edge of the inclined section and the straight section is 0.5-2 °.

Optionally, a second side edge of the inclined angle section close to the rotation center of the punching sheet body is arranged in a collinear way with the straight line section.

Optionally, the straight line segment occupies 1/2-3/4 of the length of the magnetic steel accommodated in the magnetic steel groove along the surface of the punching sheet body.

Optionally, the punching sheet body is made of an amorphous alloy material.

Optionally, the number of the magnetic steel slots is multiple, a magnetic steel slot group forming a rotor magnetic pole is formed in the multiple magnetic steel slots, the magnetic steel slot group includes a first magnetic steel slot and a second magnetic steel slot which are symmetrically arranged about the first diameter of the punching sheet body, and the first magnetic steel slot and the second magnetic steel slot are arranged in a first V shape with an outward opening.

Optionally, the magnetic steel slot group further includes a third magnetic steel slot and a fourth magnetic steel slot symmetrically arranged about the first diameter, and the third magnetic steel slot and the fourth magnetic steel slot are arranged in a second V-shape with an outward opening and are arranged at intervals on the radial inner sides of the first magnetic steel slot and the second magnetic steel slot.

Optionally, the included angle of the second V-shape is smaller than the included angle of the first V-shape.

Optionally, the magnetic steel slot groups are multiple to form multiple rotor magnetic poles respectively, and the multiple magnetic steel slot groups are even and are uniformly distributed on the punching sheet body along the circumferential direction.

Optionally, the number of the magnetic steel slot groups is four to form two pairs of poles of the motor rotor.

Optionally, oil holes are formed in the punching sheet body and are evenly distributed along the circumferential direction, and the oil holes are located between the adjacent magnetic steel groove groups.

Optionally, a rotating shaft hole is formed in the rotating center of the punching sheet body, a pair of key grooves for matching with the rotating shaft is symmetrically formed on the side wall of the rotating shaft hole, the key grooves protrude towards the circle center, and the key grooves are located on the first diameter.

Optionally, in the magnetic steel slot group, reinforcing ribs are arranged between the magnetic steel slots which are symmetrically arranged, and a magnetic isolation bridge or a magnetic isolation hole is arranged between the magnetic steel slot and the edge of the punching sheet body.

Optionally, the motor rotor punching is an ultra-high speed motor rotor punching.

The invention also provides a motor rotor, which comprises a rotor core formed by overlapping a plurality of rotor punching sheets, wherein the rotor punching sheets are the motor rotor punching sheets provided by the invention.

The invention also provides a motor, which comprises a shell, and a motor rotor and a motor stator which are arranged in the shell, wherein the motor rotor is the motor rotor provided by the invention.

The invention also provides an electric automobile which comprises the driving motor.

Through above-mentioned technical scheme, through setting up the inclination section that leans out in straightway both sides, can provide the buffer that produces the micro-deformation for the magnet steel both ends in the magnet steel groove, thereby when the rotor rotates promptly, thereby allow the magnet steel to release the inside tensile stress that produces of magnet steel in the magnet steel inslot micro-deformation, promote the life-span of magnet steel then, be particularly useful for among the electric automobile use of the driving motor of hypervelocity work.

Additional features and advantages of the invention will be set forth in the detailed description which follows.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:

FIG. 1 is a first perspective view of a motor according to an embodiment of the present invention;

FIG. 2 is a second perspective view of a motor according to an embodiment of the present invention;

fig. 3 is a schematic diagram of an exploded structure of a motor according to an embodiment of the present invention;

fig. 4 is a schematic structural diagram of a rotor sheet of an electric motor according to an embodiment of the present invention;

FIG. 5 is a schematic structural diagram of a magnetic steel slot provided in an embodiment of the present invention, wherein the included angle is enlarged by several times to show the included angle for clarity, without changing other features;

fig. 6 is a schematic structural diagram of an electric vehicle according to an embodiment of the present invention.

Detailed Description

The following detailed description of embodiments of the invention refers to the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.

In the present invention, unless otherwise specified, the use of the directional terms such as "upper, lower, left, and right" is generally defined with reference to the drawing plane direction of the drawings, and "inner and outer" refer to the inner and outer of the outline of the corresponding component.

As shown in fig. 1 to 6, the present invention at least provides a motor rotor sheet, a motor rotor, a motor 1000 and an electric vehicle 2000. The motor 1000 may be a two-pair-pole motor, a permanent magnet synchronous motor, or a two-pair-pole permanent magnet synchronous motor, and the motor of the present invention may also be other types of motors known in the art, such as an asynchronous motor, and the like, and particularly, may be an ultra-high speed motor, i.e., a motor having a rotation speed of 20000rpm or more.

The terms "two pairs of poles" and "permanent magnet synchronous" are well known in the art, and for example, two pairs of poles refer to two pairs of magnetic poles arranged on a rotor of an electric motor. The more the magnetic pole pairs are, when the rotating speed of the motor is high, particularly when the motor is an ultra-high speed motor, the higher the alternating frequency of a magnetic field is, the more heat is generated by the motor, the higher the requirement on a cooling system is, and in addition, the iron loss of the motor is increased. Therefore, the two-pair-pole motor is more suitable for a driving motor running at ultra high speed. Of course, in other possible embodiments, three or four pairs of poles, etc. may be used.

In addition, the permanent magnet synchronous motor is also more suitable for being used as a driving motor of an electric automobile. In terms of performance, it may include the advantages of high efficiency, high power factor, small size, light weight, and low temperature rise. Specifically, for example, after the permanent magnet is embedded in the rotor of the permanent magnet synchronous motor, the permanent magnet establishes a rotor magnetic field, the rotor and the stator magnetic field run synchronously during normal operation, no induced current exists in the rotor, no rotor resistance loss exists, and the motor efficiency is greatly improved. In addition, when starting, the motor has enough starting torque, does not need too large starting current, and is suitable for a driving motor driven by a power battery pack. In addition, the efficiency of the permanent magnet synchronous motor is high, the resistance loss in the rotor winding is low, and the stator winding has little or almost no reactive current, so that the temperature rise of the motor is low, and the service life of the motor can be prolonged. The advantages brought by other permanent magnet synchronous motors are not described in more detail. In a word, the permanent magnet synchronous motor has simple structure, reduces the processing and power distribution cost, is more reliable in operation, increases the air gap flux density after adopting the rare earth permanent magnet, and improves the rotating speed of the motor to the best, thereby obviously reducing the volume of the motor and improving the power-to-mass ratio; in addition, the excitation copper consumption is saved, so that the motor efficiency is obviously improved.

Structurally, as shown in fig. 1 to 3, the motor provided in the embodiment of the present invention includes a housing 400, a motor rotor 300 and a motor stator 500 installed in the housing 400, where the motor rotor 300 includes a rotor core 310 formed by stacking a plurality of rotor sheets, and further includes a rotating shaft 320 in transmission connection with the rotor core 310, specifically in the embodiment, a rotating shaft hole 101 is formed in a rotation center of a sheet body 100 of the rotor core, and a pair of key slots 102 for matching with the rotating shaft is symmetrically formed on a side wall of the rotating shaft hole 101, that is, the rotor core 310 and the rotating shaft 320 are in a key connection manner. In other embodiments, the two may be connected by other drive connections known to those skilled in the art, such as a non-circular profile connection. In addition, an oil hole 103 may be formed in the rotor sheet to form a part of the rotor oil path.

In addition, the housing 400 has an end cap 800 far from the power output end, a bearing chamber may be formed on the end cap 800, the inner end of the rotating shaft 320 is installed in the bearing chamber through the ceramic ball deep groove bearing 600, and the outer end extending out of the housing 400 may be used as the power output end. In addition, the junction box 700 mounted on the housing can be connected to an external power source, for example, the junction box can be electrically connected to a power battery pack, and can also generate a magnetic field by supplying power to the winding 900, so that the motor can work. In addition, an air gap is arranged between the rotor and the stator of the motor so that the motor can work normally.

In the embodiment of the present invention, as shown in fig. 4, the provided rotor punching sheet of the motor includes a punching sheet body 100, a magnetic steel slot 200 for inserting magnetic steel is formed on the punching sheet body 100, that is, the magnetic steel is used as a permanent magnet to form a rotor magnetic pole, that is, the permanent magnet in the embodiment adopts an embedded installation mode, so that stability during ultra-high speed rotation of the rotor can be effectively ensured, and the installation mode is more suitable for a rotor operating at ultra-high speed than a surface-mounted permanent magnet installation mode. During high-speed, in particular ultra-high-speed, operation of the rotor, the magnetic steel contained in the magnetic steel slots tends to deform under the action of centrifugal force, i.e., tensile stress is generated inside the magnetic steel slots, and the magnetic steel is subjected to compressive stress due to the resistance of the magnetic steel slots, wherein the tensile strength of the magnetic steel is much lower than the compressive strength of the magnetic steel. In one embodiment of the magnetic steel, the tensile strength is only 85Mpa, and the compressive strength can reach more than 1000 Mpa. The resulting tensile stress can have an effect on the life of the magnetic steel. Based on this, in order to prolong the service life of the magnetic steel in the embodiment, the groove shape of the magnetic steel groove is improved, and the mode may include converting the tensile stress applied to the magnetic steel into the compressive stress.

As shown in fig. 5, the magnetic steel slot 200 has a straight line segment 201 and an inclined angle segment 202 located at two sides of the straight line segment 201 along the surface direction of the punch body 100, and a first side edge of the inclined angle segment 202 away from the rotation center of the punch body 100 is inclined outward from an end of the straight line segment 201. Like this, set up the inclination section that leans out through 201 both sides in straightway, can provide the buffers that produce the micro-deformation for the magnet steel both ends in magnet steel groove 200, when the rotor rotates promptly, thereby allow the magnet steel to release the inside tensile stress that produces of magnet steel in magnet steel groove 200 micro-deformation, promote the life-span of magnet steel then.

Specifically, in the present embodiment, in order to improve the magnetic steel slot 200, an existing linear magnetic steel slot may be chamfered. In order to avoid an excessive influence on the strength of the rotor sheet, in the present embodiment, an included angle α between the first side edge of the inclined section 202 and the straight-line section 201 is 0.5 ° to 2 °, for example, an inclination of 1 ° is adopted. It should be noted here that fig. 5 is a view obtained by magnifying the included angle α by several times without changing other features, so as to clearly show the inclination angle section 202 schematically. This kind of improvement to magnet steel groove 200 can effectively increase the life-span of magnet steel, but can cause certain influence to the intensity of punching the piece body 100. Therefore, the punching sheet body 100 in the present embodiment is made of an amorphous alloy material, that is, the rotor core in the present embodiment is made of an amorphous alloy material.

As is known, the tensile strength of the amorphous alloy material is several tens times that of the common silicon steel material, so the strength sacrificed by the improvement of the magnetic steel slot 200 can be compensated by the amorphous alloy material, and is greatly higher than the strength of the rotor sheet made of the silicon steel material in the prior art, thereby not only ensuring the service life of the magnetic steel, but also ensuring the strength and the service life of the rotor core.

In addition, in the embodiment of the invention, because the rotor core is made of the amorphous alloy material, the rotor core has the characteristics of high magnetic conductivity, high electric conductivity, small eddy current loss and the like, and the performance of the motor is greatly improved. The inventor of the invention finds that the material can not only improve the rotor capacity, but also solve the key problem of how to realize high-power output through a small volume, and the breakthrough in the technology can make the driving motor in the field of electric automobiles make great progress.

Specifically, the inventor of the present invention has designed the idea that, in the field of electric vehicles, it is difficult to maximize the volume of the motor, i.e., to increase the torque of the motor, due to space layout considerations. In order to increase the power, it is known from the formula p ═ T × n/9550 that a large power output can be achieved by increasing the rotational speed in the case of a small volume. Therefore, the inventors of the present invention have produced a motivation for using a motor having a small volume and a large rotational speed as a driving motor of an electric vehicle. The inventor also considers that the volume of the designed motor is too small due to the limitation of the yield strength of the common silicon steel sheet after the rotating speed of the motor reaches the ultra high speed of 20000 rpm. When the motor volume is too small, the torque output by the motor is directly affected despite the high rotation speed, and thus the requirement for driving the motor cannot be satisfied.

In consideration of the factors, the inventor of the application adopts the amorphous alloy material to make the rotor to solve the problem of limited outer diameter of the rotor, namely, the volume of the motor is increased as much as possible to increase the torque and further improve the power of the motor while ensuring that the motor can run at a super high speed. Further, the present invention provides a motor that does not simply use amorphous alloy materials for all components. Besides the cost factor, the invention also finds that under the current process condition, the width of the amorphous alloy strip is limited, and if the amorphous alloy strip is used as a motor stator, the produced motor is too small to influence the power output of the motor. In addition, the amorphous alloy material has a large magnetostriction coefficient, which results in large vibration noise of the motor. Therefore, in the various motors provided by the embodiment of the invention, the rotor core is made of the amorphous alloy material, and the stator can be made of the existing silicon steel material. Therefore, the rotor is made of amorphous alloy material, and the stator is made of silicon steel material, which is a structure comprehensively considering various factors, and requires a great deal of creative work of the inventor.

And further, this is contrary to the above-mentioned idea of using amorphous alloy material to manufacture the rotor core to improve the life of the magnetic steel at the time of ultra-high speed operation. Therefore, the amorphous alloy material is skillfully used for manufacturing the rotor, the beneficial effect of prolonging the service life of the magnetic steel during ultrahigh-speed operation can be achieved, the designed motor can be smaller but not too small in size, unexpected technical effects are also generated by manufacturing the rotor core by adopting the amorphous alloy material, and various effects of one characteristic are realized. The motor is particularly suitable for the requirements of a driving motor which needs high power and small volume, so that the performance of the driving motor is greatly improved.

Returning to the punching sheet of the motor rotor provided in this embodiment, as shown in fig. 5, in order to ensure that the deformations on both sides of the magnetic steel are consistent, the two inclined angle sections 202 may be designed to be symmetrically arranged with respect to the center of the straight line section 201. I.e., the two angular segments 202 are substantially identical in construction. In addition, in order to realize the structure of the magnetic steel, the second side edge of the inclination angle section 202 close to the rotation center of the punching sheet body 100 is arranged in line with the straight line section 201. That is, only the first side edge line on the outer side in the inclination angle section inclines relative to the straight line section 201, so that the outward micro deformation of the two ends of the magnetic steel under the action of centrifugal force can be ensured, and the magnetic steel can be better accommodated and kept in the magnetic steel groove 200. Further, in order to better adapt to the deformation of the magnetic steel, the straight line segment 201 can be designed to occupy 1/2-3/4 of the length of the magnetic steel contained in the magnetic steel groove along the surface of the punching sheet body 100. Therefore, the deformation of the magnetic steel is better buffered, and unnecessary destructive force is prevented from being applied to the magnetic steel by the magnetic steel groove.

The groove type improvement of the magnetic steel groove 200 is introduced above, and the improvement in the arrangement of the magnetic poles in the rotor sheet of the motor in the embodiment of the present invention is described below.

In order to form a rotor magnetic pole, as shown in fig. 4, a plurality of magnetic steel slots 200 are formed, and a magnetic steel slot group constituting the rotor magnetic pole is formed in the plurality of magnetic steel slots 200, that is, one magnetic steel slot group can form one rotor magnetic pole, wherein the magnetic steel slot group includes a first magnetic steel slot 210 and a second magnetic steel slot 220 which are symmetrically arranged about a first diameter of a punching sheet body, and the first magnetic steel slot and the second magnetic steel slot are arranged in a first V shape which is open outwards. In other words, the magnetic steel arrangement mode of the invention is a V-shaped structure. Also in order to generate a larger magnetic field in a smaller size, in the present embodiment, the magnetic steel slot group further includes a third magnetic steel slot 230 and a fourth magnetic steel slot 240 symmetrically arranged about the first diameter, the third magnetic steel slot and the fourth magnetic steel slot are arranged in a second V-shape that is open to the outside and are spaced apart from each other and disposed radially inside the first magnetic steel slot and the second magnetic steel slot. Namely, one magnetic pole in the invention can comprise four magnetic steels, so that the space of the punching sheet body is fully utilized, and the magnetic pole is particularly suitable for a driving motor with smaller volume. In order to optimize the layout of the four magnetic steels in the same group and reasonably utilize the space, optionally, the included angle of the second V-shaped is smaller than that of the first V-shaped. Like this, can make the magnet steel in the outside better utilize towards the space of piece body string line direction, and make inboard magnet steel better utilize towards the space of piece body radial direction, it is more reasonable to arrange, produces the magnetic field more effectively.

In order to generate a uniform magnetic field, in the present embodiment, the number of the magnetic steel slot groups is even, and the magnetic steel slot groups are uniformly distributed on the punching sheet body along the circumferential direction. In the two-pair-pole motor provided by the invention, the number of the magnetic steel slot groups is four correspondingly so as to form two pairs of poles of the motor rotor. In other embodiments, different numbers of magnetic steel groove groups can be arranged according to different pole pairs.

In the present embodiment, in order to ensure the strength of the punching sheet body, the punching sheet body 100 is formed with oil holes 103 uniformly distributed along the circumferential direction, the oil holes 103 are located between adjacent magnetic steel groove groups to fully utilize the space of the punching sheet body, and additionally, the oil holes 103 are formed to reduce the weight of the rotor and reduce the rotational inertia of the rotor. In the present embodiment, a rotation shaft hole 101 is formed at the rotation center of the punching sheet body 100, a pair of key grooves 102 for engaging with the rotation shaft are symmetrically formed on the side wall of the rotation shaft hole 101, the key grooves 102 protrude toward the center of the circle, and the key grooves 102 are located on the first diameter. That is, the key groove is a convex structure rather than a concave structure, so that the key groove can be matched with the key groove on the rotating shaft to transmit torque conveniently.

In addition, in order to ensure the strength of the punching sheet body, in the embodiment, reinforcing ribs are arranged between the magnetic steel grooves which are symmetrically arranged in the magnetic steel groove group so as to enhance the strength of the punching sheet body. In addition, a magnetic isolation bridge or a magnetic isolation hole is arranged between the magnetic steel groove and the edge of the punching sheet body. The smaller the magnetic isolation bridge, the better, thereby reducing the magnetic leakage and increasing the air gap flux density. In addition, the magnetic isolation holes can improve the air gap flux density waveform, so that the performance of the motor is improved.

The motor provided by the invention is more suitable for a driving motor of an electric automobile, has lower iron loss, improves the output power and avoids the problem of high noise caused by an amorphous motor. The stator and rotor structures are redesigned. The strength of the rotor structure is improved, the motor can be made into an ultrahigh rotating speed motor, and the electromagnetic performance is excellent. Only the rotor core is made of amorphous alloy, so that the processing difficulty is reduced, and the process cost is reduced. The volume is not limited by amorphous alloy materials, and the motor can exert larger torque and power. Under high rotational speed, the alternating frequency of magnetic field has been minimized, the iron loss has been reduced, the heat dissipation has been reduced to easily the control of motor, make the performance of motor show the improvement, indirectly make electric automobile's performance also promote by a wide margin, the practicality is better.

The preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, however, the present invention is not limited to the specific details of the above embodiments, and various simple modifications can be made to the technical solution of the present invention within the technical idea of the present invention, and these simple modifications are within the protective scope of the present invention.

It should be noted that the various technical features described in the above embodiments can be combined in any suitable manner without contradiction, and the invention is not described in any way for the possible combinations in order to avoid unnecessary repetition.

In addition, any combination of the various embodiments of the present invention is also possible, and the same should be considered as the disclosure of the present invention as long as it does not depart from the spirit of the present invention.

Claims (10)

1. A motor rotor punching sheet comprises a punching sheet body (100), wherein a magnetic steel groove (200) for inserting magnetic steel is formed in the punching sheet body (100), and the motor rotor punching sheet is an ultra-high speed motor rotor punching sheet, wherein the ultra-high speed motor is a motor with the rotating speed of more than 20000 rpm; the punching sheet body (100) is made of amorphous alloy materials, the tensile strength of the magnetic steel is 85Mpa, the magnetic steel groove (200) is provided with a straight line section (201) and inclined angle sections (202) positioned on two sides of the straight line section (201) along the surface direction of the punching sheet body (100), the first side edge of the inclined angle section (202) far away from the rotation center of the punching sheet body (100) inclines outwards in a straight line from the end part of the straight line section (201), the second side edge of the inclination angle section close to the rotation center of the punching sheet body (100) is arranged in a collinear way with the straight line section (201), the straight line segment (201) occupies 1/2-3/4 of the length of the magnetic steel contained in the magnetic steel groove along the surface of the punching sheet body (100), the two inclined angle segments (202) are symmetrically arranged around the center of the straight line segment (201), the included angle between the first side edge of the inclined angle section (202) and the straight line section (201) is 0.5-2 degrees;

the magnetic steel slots (200) are multiple, a magnetic steel slot group forming a rotor magnetic pole is formed in the magnetic steel slots (200), the magnetic steel slot group comprises a first magnetic steel slot (210) and a second magnetic steel slot (220) which are symmetrically arranged about a first diameter of the punching sheet body, the first magnetic steel slot and the second magnetic steel slot are arranged in a first V shape with an outward opening, reinforcing ribs are arranged between the magnetic steel slots which are symmetrically arranged in the magnetic steel slot group, and a magnetic separation bridge or a magnetic separation hole is arranged between the magnetic steel slots and the edge of the punching sheet body.

2. The electric machine rotor lamination of claim 1, wherein the magnetic steel slot set further comprises a third magnetic steel slot (230) and a fourth magnetic steel slot (240) symmetrically arranged about the first diameter, the third magnetic steel slot and the fourth magnetic steel slot are arranged in a second V-shape that is open outwards and are arranged at intervals radially inside the first magnetic steel slot and the second magnetic steel slot.

3. The motor rotor punching sheet according to claim 2, wherein the included angle of the second V-shaped is smaller than the included angle of the first V-shaped.

4. The electric machine rotor punching sheet according to any one of claims 1 to 3, wherein the number of the magnetic steel groove groups is even and evenly distributed on the punching sheet body along the circumferential direction so as to respectively form a plurality of rotor magnetic poles.

5. The electric machine rotor lamination of claim 4, wherein the number of magnetic steel slot groups is four to form two pairs of poles of the electric machine rotor.

6. The motor rotor punching sheet according to claim 4, wherein oil holes (103) are formed in the punching sheet body (100) and are uniformly distributed along the circumferential direction, and the oil holes are located between the adjacent magnetic steel groove groups.

7. The motor rotor punching sheet according to claim 6, wherein a rotating shaft hole (101) is formed at the rotating center of the punching sheet body (100), a pair of key grooves (102) for matching with a rotating shaft are symmetrically formed on the side wall of the rotating shaft hole (101), the key grooves (102) protrude towards the circle center, and the key grooves (102) are located on the first diameter.

8. An electric motor rotor, the electric motor rotor (300) comprising a rotor core (310) formed by stacking a plurality of rotor sheets, wherein the rotor sheets are the electric motor rotor sheets according to claim 1.

9. An electric machine comprising a housing (400), an electric machine rotor (300) mounted in the housing (400) and an electric machine stator (500), characterized in that the electric machine rotor (300) is an electric machine rotor according to claim 8.

10. An electric vehicle comprising a drive motor, characterized in that the drive motor is an electric motor according to claim 9.

Images