Rotor core, rotor assembly, tangential permanent magnet motor, power assembly and vehicle

Abstract

The utility model provides a rotor core, a rotor assembly, a tangential permanent magnet motor, a power assembly and a vehicle. The rotor core comprises a rotor body. The rotor body comprises a plurality of magnetic pole parts arranged in an array mode in the circumferential direction of the rotor body. The magnetic pole part comprises at least two magnetic steel grooves suitable for accommodating the permanent magnets. Each magnetic steel groove of each magnetic pole part extends along a first direction parallel to the quadrature axis of the magnetic pole part. The magnetic steel grooves of each magnetic pole part are arranged at intervals in the second direction perpendicular to the quadrature axis of the magnetic pole part. And part of the rotor body between the adjacent magnetic steel grooves of each magnetic pole part forms a magnetic bridge. According to the utility model, under the condition that the same amount of permanent magnets is adopted, the air gap flux density can be improved, so that the permanent magnet torque can be improved, and the electromagnetic torque can be further improved.

Description

Technical Field

[0001] The utility model generally relates to the technical field of motors, and more specifically to a rotor core, a rotor assembly, a tangential permanent magnet motor, a power assembly and a vehicle. Background Art

[0002] The tangential permanent magnet motor in the related art has a unique magnetizing direction, which makes the electromagnetic torque output by the motor almost entirely permanent magnet torque. The size of the permanent magnet torque depends on the air gap flux density of the motor. In order to further improve the permanent magnet torque of the tangential permanent magnet motor, the air gap flux density is usually increased by increasing the height and / or thickness of the permanent magnet. However, when the amount of permanent magnet increases to a certain extent, the motor begins to saturate. At this time, continuing to increase the thickness of the permanent magnet has little effect on improving the air gap flux density. And the height of the permanent magnet is limited by the volume of the rotor. Utility Model Content

[0003] A series of simplified concepts are introduced in the utility model content section, which will be further described in detail in the detailed implementation section. The utility model content section does not mean to attempt to define the key features and essential technical features of the technical solution claimed for protection, nor does it mean to attempt to determine the scope of protection of the technical solution claimed for protection.

[0004] In order to at least partially solve the above-mentioned problems, the first aspect of the utility model provides a rotor core suitable for a tangential permanent magnet motor, wherein the rotor core comprises a rotor body, the rotor body comprises a plurality of magnetic pole portions arranged in an array along the circumference of the rotor body, the magnetic pole portions comprise at least two magnetic steel slots suitable for accommodating permanent magnets, each of the magnetic steel slots of each magnetic pole portion extends along a first direction parallel to the intersection axis of the magnetic pole portion, and each of the magnetic steel slots of each magnetic pole portion is arranged at intervals along a second direction perpendicular to the intersection axis of the magnetic pole portion, and the rotor body further comprises a plurality of magnetic bridges, and in each of the magnetic pole portions, the magnetic bridges are provided between adjacent magnetic steel slots.

[0005] According to the rotor core of the first aspect of the utility model, compared with the rotor core of the conventional tangential permanent magnet motor, the magnetic steel slot originally used to install a single permanent magnet is divided into at least two magnetic steel slots with smaller dimensions in the second direction, so as to form a magnetic bridge between adjacent magnetic steel slots. In this way, when the rotor core is applied to the tangential permanent magnet motor, under the condition of using the same amount of permanent magnets, the magnetic bridge structure can increase the air gap flux density, thereby increasing the permanent magnet torque, and further increasing the electromagnetic torque.

[0006] Optionally, at a single magnetic pole portion, the sum of the size of each magnetic steel slot in the second direction and the size of each magnetic bridge in the second direction is B mbThe sum of the dimensions of each magnetic bridge in the second direction is B mp ,but

[0007]

[0008] Optionally, a single magnetic pole portion is provided with at least two magnetic bridges, and the sizes of the magnetic bridges at the single magnetic pole portion in the second direction are the same.

[0009] Optionally, the sizes of the magnetic steel slots at a single magnetic pole portion in the second direction are the same.

[0010] Optionally, a single magnetic pole portion is provided with at least two magnetic bridges, and at the single magnetic pole portion, at least some of the magnetic bridges have different sizes in the second direction.

[0011] Optionally, at a single magnetic pole portion, dimensions of at least some of the magnetic steel slots in the second direction are different.

[0012] Optionally, the minimum distance between the magnetic steel slot and the outer circumferential surface of the rotor body in the first direction is 0.7 mm to 1.0 mm.

[0013] Optionally, the minimum distance between the magnetic steel slot and the inner circumferential surface of the rotor body in the first direction is 1 / 4 to 3 / 8 of the size of the magnetic steel slot along the first direction.

[0014] Optionally, the outer diameter of the rotor body ranges from 55 mm to 65 mm.

[0015] Optionally, each of the magnetic pole portions includes two magnetic steel slots, and the two magnetic steel slots are symmetrically arranged about the intersection axis corresponding to the magnetic pole portion.

[0016] A second aspect of the utility model provides a rotor assembly suitable for a tangential permanent magnet motor. The rotor assembly comprises the above-mentioned rotor core and permanent magnets. The permanent magnets are arranged in magnetic steel slots of the rotor core.

[0017] According to the rotor assembly of the second aspect of the utility model, by applying the above-mentioned rotor core, when the rotor assembly is applied to a tangential permanent magnet motor, the air gap flux density can be increased while using the same amount of permanent magnets, thereby increasing the electromagnetic torque.

[0018] A third aspect of the utility model provides a tangential permanent magnet motor, wherein the tangential permanent magnet motor comprises the above-mentioned rotor core, or the tangential permanent magnet motor comprises the above-mentioned rotor assembly.

[0019] According to the tangential permanent magnet motor of the third aspect of the utility model, by applying the above-mentioned rotor assembly, the air gap flux density can be increased while using the same amount of permanent magnets, thereby increasing the electromagnetic torque.

[0020] Optionally, the tangential permanent magnet motor further comprises a stator assembly surrounding the outer circumference of the rotor assembly, an air gap is formed between the stator assembly and the rotor assembly, and the length of the air gap of the tangential permanent magnet motor in the radial direction is less than 0.6 mm.

[0021] A fourth aspect of the utility model provides a power assembly, which includes the above-mentioned tangential permanent magnet motor.

[0022] According to the power assembly of the fourth aspect of the utility model, the power performance of the power assembly can be improved by applying the above-mentioned tangential permanent magnet motor.

[0023] A fifth aspect of the utility model provides a vehicle, which includes the above-mentioned tangential permanent magnet motor or the above-mentioned power assembly.

[0024] According to the vehicle of the fifth aspect of the utility model, by applying the above-mentioned tangential permanent magnet motor or the above-mentioned power assembly, the power performance of the vehicle can be improved, thereby helping to meet the user's demand for power use and further improving the user experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The following drawings of the embodiments of the present invention are used as part of the present invention for understanding the present invention. The drawings show the embodiments of the present invention and their descriptions, and are used to explain the principles of the present invention. In the drawings,

[0026] Figure 1 It is a front view of a rotor assembly according to a preferred embodiment of the utility model;

[0027] Figure 2 for Figure 1 A front view of the rotor core in FIG. 1 ; and

[0028] Figure 3 for Figure 1 A partial view of the rotor assembly at a single magnetic pole section is shown.

[0029] Description of reference numerals:

[0030] 100: Rotor assembly 110: Rotor core

[0031] 111: Rotor body 112: Magnetic steel slot

[0032] 113: Magnetic bridge 115: Magnetic pole

[0033] 120: Permanent magnet P1: Cross axis

[0034] D1: First direction D2: Second direction

[0035] AX: Central axis DETAILED DESCRIPTION

[0036] In the following description, a large number of specific details are given to provide a more thorough understanding of the present invention. However, it is obvious to those skilled in the art that the present invention can be implemented without one or more of these details. In other examples, in order to avoid confusion with the present invention, some technical features known in the art are not described.

[0037] In order to fully understand the implementation of the present invention, a detailed structure will be presented in the following description. Obviously, the implementation of the implementation of the present invention is not limited to the specific details familiar to those skilled in the art.

[0038] It should be understood that the purpose of the terms used herein is only to describe specific embodiments and is not intended to limit the present invention, and the singular forms "a", "an" and "said" / "the" are also intended to include plural forms, unless the context clearly indicates otherwise. When the terms "comprise" and / or "include" are used in this specification, they indicate the presence of the features, integral bodies, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integral bodies, steps, operations, elements, components and / or combinations thereof.

[0039] Ordinal numbers such as "first" and "second" cited in the present invention are merely identifiers and do not have any other meaning, such as a specific order. Moreover, for example, the term "first component" itself does not imply the existence of a "second component", and the term "second component" itself does not imply the existence of a "first component". It should be noted that the terms "upper", "lower", "front", "back", "left", "right", "inner", "outer" and similar expressions used in the present invention are for illustrative purposes only and are not limiting.

[0040] The "parallel" / "vertical" and similar expressions used in the present invention include an absolute parallel / vertical relationship and a roughly parallel / vertical relationship (for example, a relationship that differs from absolute parallel / vertical by -5° to +5°), which can have the same effect.

[0041] Hereinafter, specific embodiments of the present invention will be described in more detail with reference to the accompanying drawings. These drawings show representative embodiments of the present invention and are not intended to limit the present invention.

[0042] The tangential permanent magnet motor of the related art has a unique magnetizing direction that makes the motor's cross axis on the center line of the permanent magnet. The magnetic permeability of the permanent magnet is very low and close to that of air, so the cross-axis magnetic circuit presents a high magnetic resistance, so the cross-axis inductance of the motor is small. The electromagnetic torque output by the motor is almost entirely permanent magnet torque, and the reluctance torque is small, which makes the motor's reluctance torque output capacity low.

[0043] The electromagnetic torque of the motor includes reluctance torque and permanent magnet torque. The size of the permanent magnet torque depends on the air gap flux density of the motor. The method to increase the air gap flux density is usually to increase the amount of permanent magnets, that is, to increase the height and / or thickness of the permanent magnets.

[0044] The inventors found that when the amount of permanent magnets increases to a certain level, the motor begins to saturate. At this point, if the thickness of the permanent magnets is further increased, the effect on improving the air gap flux density will be minimal. The height of the permanent magnets is limited by the volume of the rotor. In this regard, the inventors believe that reducing the amount of permanent magnets can be used as a way to increase the reluctance torque.

[0045] See also Figures 1 to 3 The utility model provides a rotor core 110 , a rotor assembly 100 having the rotor core 110 , and a tangential permanent magnet motor having the rotor assembly 100 .

[0046] The rotor core 110 according to the utility model may include a rotor body 111 and a plurality of magnetic pole portions 115 provided on the rotor body 111. The plurality of magnetic pole portions 115 are arranged in an array in the circumferential direction of the rotor body 111. Each magnetic pole portion 115 may include at least two magnetic steel slots 112 suitable for accommodating permanent magnets 120. Each group of magnetic steel slots 112 is arranged in an array along the circumference of the rotor body 111. The magnetic steel slots 112 of each magnetic pole portion 115 extend in a first direction D1 parallel to the cross axis P1 of the magnetic pole portion 115. The magnetic steel slots 112 of each magnetic pole portion 115 are arranged at intervals in a second direction D2 perpendicular to the cross axis P1 of the magnetic pole portion 115. The portion of the rotor body 111 between the adjacent magnetic steel slots 112 of each magnetic pole portion 115 constitutes a magnetic bridge 113. In other words, the rotor body 111 may also include a plurality of magnetic bridges 113. In each magnetic pole portion 115, a magnetic bridge 113 is provided between adjacent magnetic steel slots 112. The first direction D1 and the second direction D2 are for the same magnetic pole portion 115. For different magnetic pole portions 115, the first direction is different and the second direction is different.

[0047] The quadrature axis P1 may also be referred to as the Q axis or the q axis. The full name of the quadrature axis in English is “quadrature axis”. Those skilled in the art may understand that the quadrature axis and the NS poles of the magnet are, for example, perpendicular to each other, so it is called the quadrature axis.

[0048] According to the rotor core 110 of the utility model, compared with the rotor core 110 of the traditional tangential permanent magnet motor, it is equivalent to dividing the magnetic steel slot originally used to install a single permanent magnet into at least two magnetic steel slots with smaller dimensions in the second direction D2, so as to form a magnetic bridge between adjacent magnetic steel slots. In this way, when the rotor core is applied to the tangential permanent magnet motor, under the condition of using the same amount of permanent magnets, the magnetic bridge structure can increase the air gap magnetic density, thereby increasing the electromagnetic torque. Moreover, the rotor core 110 of the utility model has a simple structure and is easy to use the same set of molds to achieve stacking manufacturing, which is conducive to reducing production costs and improving production efficiency.

[0049] It should be noted that the size of the magnetic steel slot 112 in the first direction D1 can be understood as the width of the magnetic steel slot 112. The size of the magnetic steel slot 112 in the second direction D2 can be understood as the width of the magnetic steel slot 112. The size of the magnetic steel slot 112 in the axial direction of the rotor body can be understood as the height of the magnetic steel slot 112.

[0050] See also Figure 2 For example, at a single magnetic pole portion 115, the sum of the size of each magnetic steel slot 112 in the second direction D2 and the size of each magnetic bridge 113 in the second direction D2 is B mb The sum of the dimensions of each magnetic bridge 113 in the second direction is B mp ,but

[0051]

[0052] It can be understood that the proportion of the sum of the dimensions of the magnetic bridge 113 in the second direction D2 at a single magnetic pole portion 115 is greater than zero. And the proportion of the sum of the dimensions of the magnetic bridge 113 in the second direction D2 at a single magnetic pole portion 115 is less than or equal to 1 / 6. And the proportion of the sum of the dimensions of the magnetic bridge 113 in the second direction D2 at a single magnetic pole portion 115 is equivalent to the proportion of the reduced usage of the permanent magnet 120. Within this range, a higher output torque of the motor can be obtained, the torque pulsation of the motor is relatively small, and the harmonic content of the air gap magnetic field is relatively small, which is conducive to improving the efficiency of the motor and improving NVH. When the proportion of the sum of the dimensions of the magnetic bridge 113 in the second direction D2 is equal to 1 / 6, the maximum output torque of the motor is basically equal to the maximum output torque that can be achieved by using a whole piece of magnetic steel. If the proportion of the sum of the dimensions of the magnetic bridge 113 in the second direction D2 is greater than 1 / 6, the maximum output torque of the motor will decrease.

[0053] See also Figures 1 to 3 For example, at least two magnetic bridges 113 are provided at a single magnetic pole portion 115. The sizes of the magnetic bridges 113 at the single magnetic pole portion 115 in the second direction D2 are the same. That is, the spacings of the magnetic steel slots 112 are the same. This is conducive to simplifying the production equipment and production process, facilitating manufacturing, and thus reducing production costs.

[0054] See also Figures 1 to 3 For example, the sizes of the magnetic steel slots 112 in the second direction D2 of the single magnetic pole portion 115 are the same. This is conducive to simplifying the production equipment and production process, facilitating manufacturing, and thus reducing production costs.

[0055] In one example, a single magnetic pole portion 115 includes m magnetic steel slots 112, each magnetic steel slot 112 has the same size in the second direction D2, and the spacing between adjacent magnetic steel slots 112 in the second direction D2 is the same. If the size of each magnetic steel slot 112 in the second direction D2 is B1, and the size of the magnetic bridge 113 in the second direction D2 is B2, then the size of the single magnetic pole portion 115 in the second direction D2 is B mb =m*B1+(m-1)*B2, the sum of the sizes of the magnetic bridges 113 at a single magnetic pole portion 115 in the second direction D2 is B mp =(m-1)*B2.

[0056] exist Figure 2 In the example shown, a single magnetic pole portion 115 includes two magnetic steel slots 112, each magnetic steel slot 112 has the same size in the second direction D2, and the spacing between adjacent magnetic steel slots 112 in the second direction D2 is the same. If the size of each magnetic steel slot 112 in the second direction D2 is B1, and the size of the magnetic bridge 113 in the second direction D2 is B2, then the size of the single magnetic pole portion 115 in the second direction D2 is B mb =2B1+B2. Accordingly, the sum of the dimensions of each magnetic bridge 113 at a single magnetic pole portion 115 in the second direction D2 is B mp =B2.

[0057] In an example not shown, at a single magnetic pole portion 115, the number of the magnetic bridges 113 is at least two. The sizes of at least some of the magnetic bridges 113 in the second direction D2 are different. That is, the spacings between adjacent magnetic steel slots 112 of a single magnetic pole portion 115 can be completely different or partially different.

[0058] In an example not shown, at a single magnetic pole portion 115, at least some of the magnetic steel slots 112 have different sizes in the second direction D2. That is, the sizes of the magnetic steel slots 112 in a single magnetic pole portion 115 in the second direction may be completely different or partially different.

[0059] See also Figure 2For example, the minimum distance L1 between the magnetic steel slot 112 and the outer circumference of the rotor body 111 in the first direction D1 is 0.7 mm to 1.0 mm. When the minimum distance L1 between the magnetic steel slot 112 and the outer circumference of the rotor body 111 in the first direction D1 is less than 0.7 mm, the rotor core is difficult to produce or has a low yield. When the minimum distance L1 between the magnetic steel slot 112 and the outer circumference of the rotor body 111 in the first direction D1 is greater than 1.0 mm, the permanent magnet 120 installed in the magnetic steel slot 112 will produce more leakage magnetic flux, and the utilization rate of the permanent magnet 120 is low.

[0060] See also Figure 2 For example, the minimum distance L2 between the magnetic steel slot 112 and the inner circumference of the rotor body 111 in the first direction D1 is 1 / 4 to 3 / 8 of the dimension W of the magnetic steel slot 112 along the first direction D1. When the minimum distance L2 between the magnetic steel slot 112 and the inner circumference of the rotor body 111 in the first direction is less than 1 / 4 of the dimension W of the magnetic steel slot 112 along the first direction D1, the rotor core and the rotating shaft have insufficient interference, and deformation is likely to occur during installation. When the minimum distance L2 between the magnetic steel slot 112 and the inner circumference of the rotor body 111 in the first direction D1 is greater than 3 / 8 of the dimension W of the magnetic steel slot 112 along the first direction D1, the width of the magnetic steel slot 112 is limited, and the amount of magnetic steel that can be embedded is very small. The width of the magnetic steel slot 112 here is the dimension of the magnetic steel slot 112 in the first direction D1.

[0061] See also Figure 2 Optionally, the outer diameter R of the rotor body 111 is out The range of the outer diameter R of the rotor body 111 is 55 mm to 65 mm. out The range of the permanent magnet synchronous motor is 55mm to 65mm with different pole numbers. The technical means of the utility model can effectively improve the torque density of the motor, that is, the motor can reduce the amount of permanent magnet 120 by about 16% when obtaining the same output torque.

[0062] See also Figure 2 Optionally, the inner diameter R of the rotor body 111 in The minimum value is 10mm.

[0063] Optionally, each magnetic pole portion 115 may include two magnetic steel slots 112 . The two magnetic steel slots 112 are symmetrically arranged about the cross axis P1 corresponding to the magnetic pole portion 115 .

[0064] See also Figures 1 to 3The rotor assembly 100 provided by the utility model may include the above-mentioned rotor core 110 and permanent magnets 120. The permanent magnets 120 are accommodated in the magnetic steel slots 112 of the rotor core 110. The rotor assembly 100 has a central axis AX. The cross-sectional shape of the permanent magnet 120 perpendicular to the central axis AX is adapted to the cross-sectional shape of the magnetic steel slots 112 perpendicular to the central axis AX.

[0065] According to the rotor assembly 100 of the utility model, by applying the above-mentioned rotor core 110, when the rotor assembly 100 is applied to a tangential permanent magnet motor, it is helpful to improve the quadrature axis inductance of the rotor assembly 100 while maintaining the air gap flux density unchanged, thereby increasing the air gap flux density, and then increasing the permanent magnet torque, and finally improving the output capacity of the electromagnetic torque. At the same time, the thickness of the permanent magnet 120 at each magnetic pole portion 115 can be reduced, that is, the amount of permanent magnets can be reduced.

[0066] Continue reading Figures 1 to 3 For example, the permanent magnet 120 does not extend beyond the outer circumferential surface of the rotor core 110 in the radial direction of the rotor assembly 100. This can reduce the external space occupied by the permanent magnet 120 on the rotor core 110.

[0067] The utility model further provides a tangential permanent magnet motor. The tangential permanent magnet motor may include the rotor core 110 or the rotor assembly 100 described above.

[0068] According to the tangential permanent magnet motor (not shown) of the present invention, by applying the above-mentioned rotor assembly 100, the reluctance torque density can be improved, thereby improving the electromagnetic torque output capacity, while also being conducive to simplifying the structure of the motor, improving production efficiency and reducing production costs.

[0069] According to the rotor assembly 100 of the utility model and the tangential permanent magnet motor having the rotor assembly 100, a plurality of permanent magnets 120 with smaller thickness are used at each magnetic pole portion 115 to replace a whole permanent magnet 120 with larger thickness, and a magnetic bridge 113 is arranged between each adjacent permanent magnet 120. The magnetic bridge 113 is conducive to the circulation of the magnetic flux of the quadrature axis P1, that is, it can increase the inductance of the quadrature axis P1, thereby increasing the motor salient pole ratio, and further improving the reluctance torque output capacity. Taking the arrangement of two permanent magnets at each magnetic pole portion 115 as an example, according to research, compared with the use of a whole permanent magnet, the total thickness of the two permanent magnets can be reduced by one-sixth, while the air gap magnetic flux density can be maintained at the original level, and the size of the magnetic bridge 113 in the second direction shall not exceed two-thirds of any one of the two permanent magnets 120.

[0070] For example, the tangential permanent magnet motor may further include a stator assembly (not shown) surrounding the outer circumference of the rotor assembly 100. An air gap is formed between the stator assembly and the rotor assembly 100. The length of the air gap of the tangential permanent magnet motor in the radial direction is less than 0.6 mm. This can improve the compactness of the radial structure of the tangential permanent magnet motor, thereby facilitating the miniaturization of the radial size of the tangential permanent magnet motor.

[0071] The tangential permanent magnet motor proposed in the utility model has a relatively uniform outer peripheral surface of the rotor core 110 in the axial direction, has no protrusions, has a simple structure, can be directly manufactured by stacking a set of molds, has a low manufacturing cost, and is easy to achieve mass production. Moreover, the tangential permanent magnet motor proposed in the utility model not only improves the torque density of the motor, but also reduces the amount of magnetic steel used and reduces costs.

[0072] The utility model also provides a power assembly (not shown). The power assembly may include the above-mentioned tangential permanent magnet motor.

[0073] According to the power assembly of the utility model, by applying the above-mentioned tangential permanent magnet motor, the power performance of the power assembly can be improved.

[0074] The utility model also provides a vehicle (not shown). The vehicle may include the above-mentioned tangential permanent magnet motor or the above-mentioned power assembly.

[0075] According to the vehicle of the present invention, by applying the above-mentioned tangential permanent magnet motor or the above-mentioned power assembly, the power performance of the vehicle can be improved, thereby helping to meet the user's demand for power use and further improving the user experience.

[0076] Unless otherwise defined, the technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art in the technical field of the present invention. The terms used herein are only for describing specific implementation purposes and are not intended to limit the present invention. Terms such as "setting" appearing in this article may indicate that one component is directly attached to another component, or that one component is attached to another component through an intermediate. Features described in this article in one embodiment may be applied to another embodiment alone or in combination with other features, unless the feature is not applicable in the other embodiment or otherwise specified.

[0077] The utility model has been described through the above embodiments, but it should be understood that the above embodiments are only for the purpose of example and description, and are not intended to limit the utility model to the described embodiments. It can be understood by those skilled in the art that more variations and modifications can be made according to the teachings of the utility model, and these variations and modifications all fall within the scope of the protection claimed by the utility model.

Claims

1. A rotor core suitable for a tangential permanent magnet motor, characterized in that: The rotor core includes a rotor body, which includes a plurality of magnetic pole portions arranged in an array along the circumference of the rotor body, the magnetic pole portions include at least two magnetic steel slots suitable for accommodating permanent magnets, each of the magnetic steel slots of each magnetic pole portion extends along a first direction parallel to the intersection axis of the magnetic pole portion, and each of the magnetic steel slots of each magnetic pole portion is arranged at intervals along a second direction perpendicular to the intersection axis of the magnetic pole portion, and the rotor body also includes a plurality of magnetic bridges, and in each of the magnetic pole portions, the magnetic bridges are provided between adjacent magnetic steel slots.

2. The rotor core according to claim 1, characterized in that: At a single magnetic pole portion, the sum of the size of each magnetic steel slot in the second direction and the size of each magnetic bridge in the second direction is B mb The sum of the dimensions of each magnetic bridge in the second direction is B mp ,but 3. The rotor core according to claim 1, characterized in that: A single magnetic pole portion is provided with at least two magnetic bridges, and the magnetic bridges at the single magnetic pole portion have the same size in the second direction.

4. The rotor core according to claim 1, characterized in that: The sizes of the magnetic steel slots at a single magnetic pole portion in the second direction are the same.

5. The rotor core according to claim 1, characterized in that: A single magnetic pole portion is provided with at least two magnetic bridges, and at the single magnetic pole portion, at least some of the magnetic bridges have different sizes in the second direction.

6. The rotor core according to claim 1, characterized in that: At a single magnetic pole portion, dimensions of at least some of the magnetic steel slots in the second direction are different.

7. The rotor core according to any one of claims 1 to 6, characterized in that: The minimum distance between the magnetic steel slot and the outer peripheral surface of the rotor body in the first direction is 0.7 mm to 1.0 mm.

8. The rotor core according to any one of claims 1 to 6, characterized in that: The minimum distance between the magnetic steel slot and the inner circumferential surface of the rotor body in the first direction is 1 / 4 to 3 / 8 of the size of the magnetic steel slot along the first direction.

9. The rotor core according to any one of claims 1 to 6, characterized in that: The outer diameter of the rotor body ranges from 55 mm to 65 mm.

10. The rotor core according to any one of claims 1 to 6, characterized in that: Each of the magnetic pole portions includes two magnetic steel slots, and the two magnetic steel slots are symmetrically arranged about the intersection axis corresponding to the magnetic pole portion.

11. A rotor assembly suitable for a tangential permanent magnet motor, characterized in that: The rotor assembly comprises a rotor core according to any one of claims 1 to 10 and a permanent magnet, wherein the permanent magnet is disposed in a magnetic steel slot of the rotor core.

12. A tangential permanent magnet motor, characterized in that: The tangential permanent magnet electric machine comprises a rotor assembly according to claim 11 .

13. The tangential permanent magnet motor according to claim 12, characterized in that: The tangential permanent magnet motor further comprises a stator assembly surrounding the outer circumference of the rotor assembly, an air gap being formed between the stator assembly and the rotor assembly. The length of the air gap of the tangential permanent magnet motor in the radial direction is less than 0.6 mm.

14. A powertrain, characterized in that: The powertrain comprises a tangential permanent magnet electric machine according to any one of claims 12 and 13.

15. A vehicle, characterized in that: The vehicle comprises a tangential permanent magnet electric machine according to any one of claims 12 and 13 or a powertrain according to claim 14 .

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