Rotor, electric machine, powertrain and power plant

Abstract

The application provides a rotor, a motor, a power assembly and a power device. The rotor comprises a rotor core and a plurality of magnets arranged uniformly along the circumference of the rotor core. Each of the magnets comprises a plurality of magnetic segments, and at least two of the magnetic segments in each of the magnets are arranged in a staggered manner along the circumference of the rotor core. The maximum skew pole angle θ between each of the magnetic segments of any of the magnets satisfies: the rotor can simultaneously weaken the cogging torque, torque ripple and low-order radial electromagnetic force of the motor.

Description

Technical Field

[0001] This application relates to the field of electric motors, specifically to a rotor, an electric motor, a powertrain, and a power unit. Background Technology

[0002] In the electric vehicle field, the motor is one of the key components. Currently, automotive motors are gradually developing towards higher speeds, higher efficiency, and lower noise. During motor rotation, due to the different electromagnetic forces experienced between the stator teeth and slots, the rotor torque fluctuates; this fluctuation is called cogging torque. Cogging torque causes vibration and noise during motor operation. Segmented magnetic rotors are one effective measure to reduce cogging torque and torque pulsation, thus lowering electromagnetic vibration. However, existing magnetic rotors only select the slant angle based on reducing cogging torque and torque pulsation in their slant angle calculations. The slant angle obtained by existing calculation methods cannot weaken the rotor's radial electromagnetic force, such as low-order radial electromagnetic forces, thus failing to further reduce motor noise. Summary of the Invention

[0003] This application provides a rotor, motor, powertrain, and power unit that can simultaneously reduce the cogging torque, torque pulsation, and low-order radial electromagnetic force of the motor.

[0004] In a first aspect, this application provides a rotor comprising a rotor core and a plurality of magnetic poles uniformly arranged circumferentially along the rotor core, each magnetic pole comprising at least one magnet arranged axially along the rotor core; wherein, along the axial direction of the rotor core, each magnet comprises a plurality of magnetic segments; at least two magnetic segments in each magnet are staggered circumferentially along the rotor core, the misalignment angle formed by the staggered arrangement of any two magnetic segments along the rotor core is the slant pole angle of the two magnetic segments, and the maximum slant pole angle θ between the magnetic segments of any magnet satisfies:

[0005]

[0006] Where Z is the number of stator slots of the motor, 2p is the total number of magnetic poles of the rotor, and n is the number of types of magnetic segments;

[0007] Z, p, and n are all taken from positive integers, and n is greater than or equal to 2 and less than or equal to the number of magnetic segments;

[0008] LCM(Z,2p) is the least common multiple of the number of stator slots and the total number of rotor poles of the motor.

[0009] For existing conventional magnet rotors, the optimal skew angle is determined by reducing cogging torque, and the maximum skew angle for each segment is selected as follows: However, it cannot effectively reduce torque pulsation and radial electromagnetic force under load. For fractional-slot concentrated winding motors, the excitation source causing motor vibration and noise is usually radial electromagnetic force at a specific harmonic frequency of low spatial order. The rotor of this application, by limiting the maximum skew pole angle between multiple magnetic segments of any magnet within the above-mentioned range, can effectively reduce the cogging torque and torque pulsation of the motor, while reducing the radial electromagnetic force at a low spatial order of 10 times the electrical frequency of the fractional-slot concentrated winding.

[0010] In one alternative implementation, in each magnet, the slant pole angle α between any two adjacent misaligned magnetic segments satisfies:

[0011]

[0012] By limiting the slant pole angle between any two adjacent staggered magnetic segments, the cogging torque and torque pulsation of the motor can be further reduced, while the radial electromagnetic force at a lower order of 10 times the electrical frequency in the fractional slot concentrated winding space can be reduced, thereby further reducing the noise of the motor.

[0013] In one alternative implementation, the arrangement of multiple magnetic segments of any magnet along the axial direction of the rotor core includes a straight-line structure, a V-shaped structure, a Z-shaped structure, or a W-shaped structure. When the magnets are configured as straight-line, V-shaped, Z-shaped, or W-shaped magnets along the axial direction of the rotor core, low cogging torque, low torque pulsation, and low-order radial electromagnetic force of the rotor can be obtained.

[0014] In one alternative implementation, the magnets are arranged in either a surface-mounted or embedded structure within the rotor core. In another alternative implementation, the magnetic poles are arranged in a straight line, a V-shape, or a double V-shape within the radial plane of the rotor core.

[0015] Secondly, this application provides an electric motor, which includes a stator, a shaft, and a rotor as described in the first aspect of this application, wherein the rotor is configured to cooperate with the stator and is fixedly connected to the shaft.

[0016] The stator is sleeved outside the rotor, or the rotor is sleeved outside the stator; the stator and the rotor are arranged coaxially.

[0017] This application provides an electric motor, including a stator, a rotor, and a shaft, wherein the stator is configured to cooperate with the rotor, and the rotor is fixedly connected to the shaft;

[0018] The rotor includes a rotor core and a plurality of magnetic poles uniformly arranged circumferentially along the rotor core, wherein each magnetic pole includes at least one magnet arranged axially along the rotor core.

[0019] Along the axial direction of the rotor core, each magnet includes multiple magnetic segments; at least two magnetic segments in each magnet are circumferentially offset from each other along the rotor core, and the misalignment angle formed by the circumferential offset between any two magnetic segments is the slant pole angle of the two magnetic segments; wherein,

[0020] The motor has 12 stator slots, 10 rotor poles, and 2 types of magnetic segments. The least common multiple of the number of stator slots and rotor poles is 60. The maximum skew angle θ between any magnetic segment of any magnet satisfies: 3° < θ ≤ 3.6°. In an optional implementation, the skew angle α between any two adjacent staggered magnetic segments in each magnet satisfies: 3° < α ≤ 3.6°.

[0021] This application provides an electric motor, including a stator, a rotor, and a shaft, wherein the stator is configured to cooperate with the rotor, and the rotor is fixedly connected to the shaft;

[0022] The rotor includes a rotor core and a plurality of magnetic poles uniformly arranged circumferentially along the rotor core, wherein each magnetic pole includes at least one magnet arranged axially along the rotor core.

[0023] Along the axial direction of the rotor core, each magnet includes multiple magnetic segments; at least two magnetic segments in each magnet are circumferentially offset from each other along the rotor core, and the misalignment angle formed by the circumferential offset between any two magnetic segments is the slant pole angle of the two magnetic segments; wherein,

[0024] The motor has 12 stator slots, 10 rotor poles, and 3 types of magnetic segments. The least common multiple of the number of stator slots and rotor poles is 60. The maximum skew angle θ between any two magnetic segments of any magnet satisfies: 4° < θ ≤ 4.8°. In an optional implementation, the skew angle α between any two adjacent staggered magnetic segments in each magnet satisfies: 2° < α ≤ 2.4°.

[0025] This application provides an electric motor, including a stator, a rotor, and a shaft, wherein the stator is configured to cooperate with the rotor, and the rotor is fixedly connected to the shaft;

[0026] The rotor includes a rotor core and a plurality of magnetic poles uniformly arranged circumferentially along the rotor core, wherein each magnetic pole includes at least one magnet arranged axially along the rotor core.

[0027] Along the axial direction of the rotor core, each magnet includes multiple magnetic segments; at least two magnetic segments in each magnet are circumferentially offset from each other along the rotor core, and the misalignment angle formed by the circumferential offset between any two magnetic segments is the slant pole angle of the two magnetic segments; wherein,

[0028] The motor has 12 stator slots, 10 rotor poles, and 4 types of magnetic segments. The least common multiple of the number of stator slots and rotor poles is 60. The maximum skew angle θ between any two magnetic segments of any magnet satisfies: 4.5° < θ ≤ 5.4°. In an optional implementation, the skew angle α between any two adjacent staggered magnetic segments in each magnet satisfies: 1.5° < α ≤ 1.8°.

[0029] This application provides an electric motor, including a stator, a rotor, and a shaft, wherein the stator is configured to cooperate with the rotor, and the rotor is fixedly connected to the shaft;

[0030] The rotor includes a rotor core and a plurality of magnetic poles uniformly arranged circumferentially along the rotor core, wherein each magnetic pole includes at least one magnet arranged axially along the rotor core.

[0031] Along the axial direction of the rotor core, each magnet includes multiple magnetic segments; at least two magnetic segments in each magnet are circumferentially offset from each other along the rotor core, and the misalignment angle formed by the circumferential offset between any two magnetic segments is the slant pole angle of the two magnetic segments; wherein,

[0032] The motor has 24 stator slots, the rotor has 10 magnetic poles, and there are 2 types of magnetic segments. The least common multiple of the number of stator slots and the total number of magnetic poles is 120. The maximum skew angle θ between any magnetic segment of any magnet satisfies: 1.5° < θ ≤ 1.8°. In an optional implementation, in each magnet, the skew angle α between any two adjacent staggered magnetic segments satisfies: 1.5° < α ≤ 1.8°.

[0033] This application provides an electric motor, including a stator, a rotor, and a shaft, wherein the stator is configured to cooperate with the rotor, and the rotor is fixedly connected to the shaft;

[0034] The rotor includes a rotor core and a plurality of magnetic poles uniformly arranged circumferentially along the rotor core, wherein each magnetic pole includes at least one magnet arranged axially along the rotor core.

[0035] Along the axial direction of the rotor core, each magnet includes multiple magnetic segments; at least two magnetic segments in each magnet are circumferentially offset from each other along the rotor core, and the misalignment angle formed by the circumferential offset between any two magnetic segments is the slant pole angle of the two magnetic segments; wherein,

[0036] The motor has 24 stator slots, 10 rotor poles, and 3 types of magnetic segments. The least common multiple of the number of stator slots and rotor poles is 120. The maximum skew angle θ between any magnetic segment of any magnet satisfies: 2° < θ ≤ 2.4°. In an optional implementation, the skew angle α between any two adjacent staggered magnetic segments in each magnet satisfies: 1° < α ≤ 1.2°.

[0037] This application provides an electric motor, including a stator, a rotor, and a shaft, wherein the stator is configured to cooperate with the rotor, and the rotor is fixedly connected to the shaft;

[0038] The rotor includes a rotor core and a plurality of magnetic poles uniformly arranged circumferentially along the rotor core, wherein each magnetic pole includes at least one magnet arranged axially along the rotor core.

[0039] Along the axial direction of the rotor core, each magnet includes multiple magnetic segments; at least two magnetic segments in each magnet are circumferentially offset from each other along the rotor core, and the misalignment angle formed by the circumferential offset between any two magnetic segments is the slant pole angle of the two magnetic segments; wherein,

[0040] The motor has 24 stator slots, the rotor has 10 magnetic poles, and there are 4 types of magnetic segments. The least common multiple of the number of stator slots and the total number of magnetic poles is 120. The maximum skew angle θ between any magnetic segment of any magnet satisfies: 2.25° < θ ≤ 2.7°. In an optional implementation, the skew angle α between any two adjacent staggered magnetic segments in each magnet satisfies: 0.75° < α ≤ 0.9°.

[0041] Thirdly, this application provides a powertrain including a reducer and a motor as described in this application, the motor being drivenly connected to the reducer.

[0042] Fourthly, this application provides a power unit that includes the power assembly as described in this application.

[0043] The technical effects that can be achieved by the second to fourth aspects mentioned above can be referred to the corresponding effect descriptions in the first aspect mentioned above, and will not be repeated here. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the structure of a rotor according to this application;

[0045] Figure 2 This is a schematic diagram of the end face structure of a rotor according to one embodiment;

[0046] Figure 3 This is a schematic diagram of the rotor structure according to another embodiment of this application;

[0047] Figure 4 This is a schematic diagram of the rotor structure according to another embodiment of this application;

[0048] Figure 5 This is a schematic diagram of the end face structure of a rotor according to one embodiment;

[0049] Figure 6 This is a schematic diagram of the structure of a magnet in one embodiment of this application;

[0050] Figure 7 This is a schematic diagram of the rotor structure according to another embodiment of this application;

[0051] Figure 8 This is a schematic diagram of the structure of a magnet according to another embodiment of this application;

[0052] Figure 9 This is a schematic diagram of the rotor structure according to another embodiment of this application;

[0053] Figure 10 This is a schematic diagram of the structure of a magnet according to another embodiment of this application;

[0054] Figure 11 This is a schematic diagram of the rotor structure according to another embodiment of this application.

[0055] Figure label:

[0056] 11-Rotor; 12-Rotor core; 121-Core segment; 13-Magnetic pole; 14-Magnet; 141-Magnetic segment. Detailed Implementation

[0057] To make the objectives, technical solutions, and advantages of this application clearer, the application will now be described in further detail with reference to the accompanying drawings.

[0058] The terminology used in the following embodiments is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. As used in the specification and appended claims of this application, the singular expressions “a,” “an,” “the,” “the,” “the,” and “this” are intended to also include expressions such as “one or more” unless the context clearly indicates otherwise.

[0059] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0060] To make it easier to understand, the following will first explain some technical terms related to motors.

[0061] Cogging torque: The torque generated by the periodic interaction between the rotor magnetic field and the teeth and slots of the motor stator.

[0062] Ripple torque: The torque generated by the harmonics of the air gap magnetic flux density. As the rotational speed increases, the high-frequency components of the air gap magnetic flux density waveform increase, generating high-frequency noise.

[0063] During motor operation, the noise sources mainly consist of three parts: 1) Electromagnetic noise: noise caused by the motor's own torque fluctuations and radial electromagnetic forces. The noise caused by radial electromagnetic forces is primarily the source of high-frequency noise in the motor. 2) Aerodynamic noise: noise generated by the friction between the motor rotor and the air during high-speed rotation. 3) Mechanical noise: vibration caused by the unbalanced forces of the motor rotor, mainly due to defects in the dynamic balance performance of the motor rotor. The most direct method to address electromagnetic noise is to minimize torque pulsation and radial electromagnetic forces during motor design. Motor torque fluctuations mainly consist of cogging torque and ripple torque. Magnetic rotors are one of the simplest and most effective measures to reduce cogging torque and torque pulsation, thereby reducing electromagnetic vibration. The contribution of cogging torque, torque pulsation, and radial electromagnetic forces to electromagnetic noise varies depending on the application scenario and operating conditions. Therefore, the selection of the skew angle must consider not only reducing cogging torque and torque pulsation but also weakening the radial electromagnetic force. The existing magnetic rotors do not take into account how to remove the influence of radial electromagnetic force when designing the slant pole angle. Especially for motors with fractional slot concentrated windings, the existing slant pole angle design cannot effectively reduce torque ripple and radial electromagnetic force, thus making it impossible to further reduce the electromagnetic noise of the motor.

[0064] To address the impact of radial electromagnetic force on motor noise, this application provides a rotor. Figure 1 This is a schematic diagram of the structure of a rotor according to this application. Figure 2 This is a schematic diagram of the end face structure of a rotor according to one embodiment. (As shown...) Figure 1 and Figure 2 As shown, the rotor 11 in this embodiment of the application includes a rotor core 12 and magnetic poles 13 disposed on the rotor core 12.

[0065] like Figure 1 and Figure 2 As shown, the rotor core 12 can be a hollow cylindrical structure. The rotor core 12 can be formed using permanent magnets. The rotor core 12 may include an inner circumferential surface, an outer circumferential surface, and an end face. The end face of the rotor core 12 can be an annular surface and can be perpendicular to the axial direction of the rotor core 12. The rotor core 12 can be composed of multiple core segments 121. For example, along the axial direction of the rotor core 12, the rotor core 12 can be divided into several core segments 121. When assembling the rotor 11, multiple core segments 121 can be stacked sequentially or fitted onto the shaft to form the rotor core 12.

[0066] Continue to refer to Figure 1 and Figure 2 The number of magnetic poles 13 can be multiple, and these multiple magnetic poles 13 can be evenly arranged along the circumference of the rotor core 12. The total number of magnetic poles of the rotor 11 can be represented by 2p, where p is the number of pole pairs and can be a positive integer greater than or equal to 1. The total number of magnetic poles can be, for example, 4, 6, 10, 16, 20, 30, 40, or more. In this embodiment, the number of magnetic poles 13 is not specifically limited. The total number of magnetic poles of the rotor 11 can be set according to the performance of the specific motor.

[0067] like Figure 2 As shown, any magnetic pole 13 can be disposed on the outer peripheral surface of the rotor core 12. Figure 3 This is a schematic diagram of another type of rotor. (Example) Figure 3 As shown, any magnetic pole 13 can also be located on the inner circumferential surface of the rotor core 12. For example... Figure 2 and Figure 3 As shown, when the magnetic pole 13 is disposed on the outer or inner circumferential surface of the rotor core 12, a surface-mounted magnetic pole structure can be formed. Figure 4 This is a schematic diagram of another type of rotor. (Example) Figure 4 As shown, any magnetic pole 13 can also be inserted inside the rotor core 12 to form a built-in magnetic pole structure.

[0068] Each magnetic pole 13 may include at least one magnet 14 arranged axially along the rotor core 12. (See reference...) Figures 2 to 4 Each magnetic pole 13 may include a magnet 14. The magnetic poles 13 may be arranged in a line in the radial plane of the rotor core 12.

[0069] Figure 5 This is a schematic diagram of the end face structure of a rotor according to one embodiment. (As shown...) Figure 5As shown, when each magnetic pole 13 includes multiple magnets 14, the multiple magnets 14 forming magnetic poles 13 can be arranged in a double V-shape within the radial plane of the rotor core 12. It can be understood that... Figures 2 to 5 For illustrative purposes only, each magnetic pole 13 may also be configured with other structures, such as a V-shaped or W-shaped arrangement.

[0070] Continue to refer to Figure 1 In one embodiment of this application, any magnet 14 in the magnetic poles 13 can extend from one end of the rotor core 12 to the other. Each magnet 14 can be divided into multiple magnetic segments 141 along the axial direction of the rotor core 12. The multiple magnetic segments 141 are connected end to end in sequence to form a magnet 14. Wherein, as... Figure 1 As shown, each magnetic segment 141 of any magnet 14 can be respectively arranged in the circumference of different iron core segments 121. During assembly, multiple iron core segments 121 are connected in sequence, and the magnetic segments 141 in the circumference of multiple iron core segments 121 are connected in sequence to form magnet 14.

[0071] Continue to refer to Figure 1 In each magnet 14, among the multiple magnetic segments 141, at least two magnetic segments 141 are offset by a certain angle along the circumference of the rotor core 12. The misalignment angle formed by the circumferential misalignment between any two magnetic segments 141 is the slant pole angle of those two magnetic segments 141. It can be understood that the slant pole angles between any two adjacent magnetic segments 141 can be the same or different. In each magnet 14, there may also be two adjacent magnetic segments 141 that are connected in a straight line, that is, there is no misalignment angle in the circumferential direction of the stator core. In the embodiments of this application, the maximum slant pole angle θ between the magnetic segments 141 of any magnet 14 satisfies:

[0072]

[0073] Where Z is the number of stator slots of the motor. 2p is the total number of magnetic poles of the rotor. Both Z and p are positive integers. LCM(Z,2p) is the least common multiple of the number of stator slots and the total number of magnetic poles of the motor. n is the number of types of magnetic segments, and n is a positive integer greater than or equal to 2, and n is less than or equal to the number of magnetic segments.

[0074] Reference Figure 1When the number of magnetic segments 141 is N, the N segments can be of the same type, different types, or partially the same. For example, when N is 4, the magnetic segments 141 can be of one type, two types, three types, or four types. When the four magnetic segments 141 are exactly the same size, each magnet 14 can include one type of magnetic segment 141. When any pair of the four magnetic segments 141 are the same size, each magnet 14 can include two types of magnetic segments 141. When the four magnetic segments 141 are all different from each other, each magnet 14 can include four types of magnetic segments 141. The above is only an illustrative example; the number and types of magnetic segments 141 in each magnet 14 can be set according to actual needs.

[0075] In an alternative embodiment, the slant pole angle α between any two adjacent staggered magnetic segments 141 in each magnet 14 satisfies:

[0076]

[0077] Figure 6 This is a schematic diagram of the structure of a magnet in one embodiment of this application. Figure 6 As shown, in one embodiment, each magnet 14 is a linear magnet 14. In the linear magnet 14, along the arrangement direction of the plurality of magnetic segments 141, the plurality of magnetic segments 141 are connected in the same square staggered manner to form a linear structure or a similar linear structure. (See also...) Figure 1 and Figure 6 In this embodiment, the maximum skew pole angle θ between each magnetic segment 141 is the misalignment angle between the first magnetic segment 141 and the last magnetic segment 141 in the circumferential direction of the rotor core 12, as shown by angle θ in 1. This angle θ satisfies equation (1). Figure 1 The angle θ in the equation is Figure 6 The distance H between the two magnetic segments 141 along the outer circumference of the rotor core 12 corresponds to the circumferential angle within the radial plane of the rotor core 12. For ease of understanding, [the following is a simplified explanation:] Figure 6 H in the figure corresponds to angle θ. The angle θ in other magnets 14 can be understood in the same way.

[0078] Furthermore, in each magnet 14 of this embodiment, the slant pole angle α between any two adjacent staggered magnetic segments 141 is the angle between any two adjacent staggered magnetic segments 141 in the circumferential direction of the rotor core 12, such as... Figure 1 and Figure 6 As shown by angle α, this angle α satisfies equation (2). Figure 1 and Figure 6 As shown, when each magnet 14 includes four magnetic segments 141, a slant angle α can exist between any two magnetic segments 141. Wherein, Figure 1 Angle α in is Figure 6The distance h between the two magnetic segments 141 along the outer circumference of the rotor core 12 corresponds to the circumferential angle within the radial plane of the rotor core 12. For ease of understanding, [the following is a simplified explanation:] Figure 6 In this context, h corresponds to angle α. The angle α in other magnets 14 can be understood in the same way. When all magnetic segments 141 are offset in the same direction, for example, when they are all offset in a clockwise direction on the outer circumference of the rotor core 12, the maximum skew pole angle θ of the magnet 14 is the sum of all angles α.

[0079] Figure 7 This is a schematic diagram of the rotor structure according to another embodiment of this application. Figure 8 This is a schematic diagram of the structure of a magnet according to another embodiment of this application. Figure 7 and Figure 8 As shown, in another embodiment of this application, the magnet 14 may be a V-shaped magnet 14. In the V-shaped magnet 14, the connections of multiple magnetic segments 141 form a V-shape or a V-like shape. Figure 8 As shown in the embodiment of this application, each magnet 14 may include four magnetic segments 141. The first and second magnetic segments 141 are offset circumferentially from each other along the rotor core 12. The second and third magnetic segments 141 are not offset angularly from each other along the circumferential direction of the rotor core 12 and are connected linearly along the axial direction of the rotor core 12. The third and fourth magnetic segments 141 are also offset circumferentially from each other along the rotor core 12. In this connection method, the maximum slant angle θ between each magnetic segment 141 can be either the slant angle α1 between the first and second magnetic segments 141 or the slant angle α2 between the third and fourth magnetic segments 141. The maximum slant angle θ is the larger of α1 and α2.

[0080] It is understood that the above is only an illustrative example. When there are more magnetic segments 141 and they are not arranged in a straight line, the maximum slant pole angle between each magnetic segment 141 in each magnet 14 can be the largest of the slant pole angles of any two adjacent staggered magnetic segments 141.

[0081] Figure 9 This is a schematic diagram of the rotor structure according to another embodiment of this application. Figure 10 This is a schematic diagram of the structure of a magnet according to another embodiment of this application. Figure 9 and Figure 10 As shown, in another embodiment of this application, the magnet 14 may be a Z-shaped magnet 14. In the Z-shaped magnet 14, the connections of multiple magnetic segments 141 form a Z-shape or a Z-like shape. Figure 10As shown in the embodiment of this application, each magnet 14 may include four magnetic segments 141. The first and second magnetic segments 141 are offset from each other circumferentially along a first direction from the rotor core 12. The second and third magnetic segments 141 are offset from each other circumferentially along a second direction from the rotor core 12. The third and fourth magnetic segments 141 are offset from each other circumferentially along the first direction from the rotor core 12. The first and second directions are opposite directions. If the first direction is clockwise, the second direction is counterclockwise. If the first direction is counterclockwise, the second direction is clockwise.

[0082] In this connection method, the maximum slant angle θ between each magnetic segment 141 can be the slant angle α1 between the first magnetic segment 141 and the second magnetic segment 141, or the slant angle α2 between the second magnetic segment 141 and the third magnetic segment 141, or the slant angle α3 between the third magnetic segment 141 and the fourth magnetic segment 141. The maximum slant angle θ is the largest of α1, α2 and α3.

[0083] Figure 11 This is a schematic diagram of the rotor structure according to another embodiment of this application. Figure 11 The rotor of the embodiment, and Figure 9 The difference in the rotor of this embodiment is that each magnet 14 is disposed on the inner circumferential surface of the rotor core 12. When the magnet 14 is disposed on the inner circumferential surface of the rotor core 12, its structure can be the same as that disposed on the outer circumferential surface. For example, the structure of the magnet 14 can be a straight line structure, a V-shaped structure, a Z-shaped structure, or a W-shaped structure, etc.

[0084] It is understood that in each rotor of this application embodiment, the magnet 14 can be connected to the rotor core 12 by means of a label, or it can be connected to the rotor core 12 by means of an internal connection. When the internal connection to the rotor core 12 is adopted, the surface of the rotor core 12 can be provided with slots for the magnet 14, and each magnet 14 can be inserted into the slot of the magnet 14 to achieve connection with the rotor core 12. When the magnet 14 adopts the internal connection method, the topology of the magnet 14 slot includes, but is not limited to, a straight internal topology, a V-shaped internal topology, or a double V-shaped internal topology.

[0085] In this embodiment of the application, the rotor's slant angle is designed by influencing the cogging torque, torque ripple, and radial electromagnetic force of the rotor through the addition of different types of magnetic segments. Therefore, the slant angle obtained using the calculation method of this embodiment can more accurately calculate the optimal slant angle, thereby reducing the impact of cogging torque, torque ripple, and radial electromagnetic force on noise. For fractional-slot motors, the impact of radial electromagnetic force on motor noise can be significantly reduced, achieving a noise reduction of over 70% compared to existing slant angle design methods.

[0086] The function of the rotor in this embodiment will be further explained in detail below, taking the 12s10p motor as an example.

[0087] Taking a 12s10p motor as an example, the number of stator slots Z is 12, the total number of rotor magnets 2p is 10, and the number of slots per pole per phase q is 2 / 5. (Refer to...) Figure 1 Each magnet 14 of the rotor 11 is divided into two magnetic segments 141. The two magnetic segments 141 are arranged in a straight line. The number of types n of magnetic segments 141 is 2. The maximum slant angle θ of each magnetic segment 141 obtained using the embodiments of this application is 3.6°. The slant angle of the magnet 14 obtained using conventional calculation methods is 3°. The noise of the motor with different slant angles is predicted by simulation, and the simulation results are listed in Table 1.

[0088] Table 1

[0089]

[0090] Among them, the loaded (2,10p) electromagnetic force is the spatial second-order 10 times the electrical frequency acting on the stator under loaded conditions, and the unloaded (2,10p) electromagnetic force is the spatial second-order 10 times the electrical frequency acting on the stator under unload conditions.

[0091] As shown in Table 1, the rotor with the skewed pole angle set according to the embodiment of this application has a significantly reduced torque pulsation compared to the conventional direct pole or 3° skewed pole rotor, with a reduction of up to 90%. The electromagnetic forces of the motor under load and under no-load (2, 10p) are greatly reduced, and the corresponding noise can be significantly reduced.

[0092] Based on the same technical concept, embodiments of this application provide a rotor assembly. The rotor assembly includes a shaft and a rotor connected to the shaft. The rotor may be the rotor provided in embodiments of this application.

[0093] Based on the same technical concept, this application provides an electric motor. The motor includes a stator and a rotor assembly according to this application. The rotor in the rotor assembly is configured to cooperate with the stator. When the magnets of the rotor are disposed on the outer peripheral surface of the rotor core, as... Figure 1 , Figure 7 and Figure 9 In the embodiment shown, the stator can be fitted onto the outside of the rotor 11 during motor assembly. When the magnets 14 of the rotor 11 are disposed on the inner circumferential surface of the rotor core 12, as... Figure 11 In the illustrated embodiment, the rotor 11 can be fitted onto the outside of the stator when forming a motor. The rotor 11 and the stator can rotate relative to each other. The rotor 11 is connected to a shaft to achieve power output.

[0094] As examples, the specific selection ranges of the θ angle and α angle for the motors of several embodiments provided in this application are listed in Table 2. The specific motor parameters and the values ​​of the θ angle and α angle are shown in Table 2.

[0095] Table 2

[0096]

[0097] The motors shown in Table 2, compared to conventional direct-pole or skew-pole rotors, exhibit significantly reduced torque pulsation, substantial reduction in (2, 10 p) electromagnetic forces under load and no-load conditions, and correspondingly, significantly reduced noise.

[0098] Based on the same technical concept, this application also provides a powertrain. The powertrain includes a reducer and a motor according to this application embodiment. The motor is connected to the reducer in a transmission configuration.

[0099] Based on the same technical concept, embodiments of this application also provide a power device. This power device includes the powertrain of embodiments of this application. The power device of this application includes, but is not limited to, electric vehicles, electric bicycles, etc.

[0100] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A rotor, characterized in that, It includes a rotor core and a plurality of magnetic poles uniformly arranged circumferentially along the rotor core, wherein each magnetic pole includes at least one magnet arranged axially along the rotor core; wherein, Along the axial direction of the rotor core, each magnet includes multiple magnetic segments; at least two magnetic segments in each magnet are circumferentially misaligned with the rotor core, and the misalignment angle formed by the circumferential misalignment between any two magnetic segments is the slant pole angle of the two magnetic segments, and the maximum slant pole angle between the magnetic segments of any magnet is... satisfy: ； Where Z is the number of stator slots of the motor, 2p is the total number of magnetic poles of the rotor, and n is the number of types of magnetic segments; Z, p and n are all taken from positive integers, and n is greater than or equal to 2 and less than the number of magnetic segments; LCM(Z,2p) is the least common multiple of the number of stator slots and the total number of rotor poles of the motor.

2. The rotor according to claim 1, characterized in that, In each of the magnets, the slant pole angle between any two adjacent staggered magnetic segments is... satisfy: 。 3. The rotor according to claim 1 or 2, characterized in that, Along the axial direction of the rotor core, the arrangement structure of the multiple magnetic segments of any magnet includes a straight line structure, a V-shaped structure, a Z-shaped structure, or a W-shaped structure.

4. The rotor according to any one of claims 1-3, characterized in that, The magnets are arranged in the rotor core in either a surface-mounted or built-in manner.

5. The rotor according to any one of claims 1-4, characterized in that, Within the radial plane of the rotor core, the magnetic poles have a straight-line structure, a V-shaped structure, or a double V-shaped structure.

6. An electric motor, characterized in that, It includes a stator, a rotating shaft, and a rotor as described in any one of claims 1-5, wherein the rotor is configured to cooperate with the stator and the rotor is fixedly connected to the rotating shaft.

7. A powertrain, characterized in that, It includes a speed reducer and a motor as described in claim 6, wherein the motor is drive-connected to the speed reducer.

8. A power unit, characterized in that, Includes the powertrain as described in claim 7.

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