Motor rotor, motor, power assembly and electric vehicle

Abstract

The utility model provides a motor rotor, a motor, a power assembly and an electric vehicle, the motor rotor comprises a rotor core and a magnetic assembly, the magnetic assembly comprises n magnetic unit pairs arranged at intervals along the circumferential direction of the rotor core, and each magnetic unit pair comprises two magnetic units, each magnetic unit comprises at least one permanent magnet and permanent magnet grooves arranged in one-to-one correspondence with the at least one permanent magnet, the permanent magnet grooves are arranged in the rotor iron core, and each permanent magnet is arranged in the corresponding permanent magnet groove. At least one permanent magnet is provided with a first surface and a second surface which are oppositely arranged in the magnetizing direction of the permanent magnet, in at least part of the magnetic units, the first surface and / or the second surface of at least one permanent magnet is configured as an arc repairing surface, the arc repairing surface is provided with at least one arc-shaped surface, and a protrusion is formed at the position of at least one arc-shaped surface. The motor rotor provided by the utility model can reduce the noise of the motor, and improves the riding comfort of electric vehicle passengers.

Description

Technical Field

[0001] The present application relates to the field of motor technology, and in particular to a motor rotor, a motor, a powertrain, and an electric vehicle. Background Art

[0002] With the rapid development of new energy vehicles, new energy powertrain systems have attracted much attention. Permanent magnet synchronous motors are an important component of electric vehicle electric drive systems.

[0003] A permanent magnet synchronous motor consists of a coaxially connected stator and rotor. The stator is mounted on the outside of the rotor. The rotating magnetic field of the stator drives the permanent magnets within the rotor, causing the rotor to rotate and providing input torque power to the electric vehicle via the motor shaft connected to the rotor. Due to the air gap between the rotor and stator, the air gap magnetic field is generated when the rotor rotates, which in turn generates electromagnetic force waves that vary in time and space, namely torque pulsation. This electromagnetic force wave causes the stator to vibrate, which in turn causes the surrounding air to vibrate, generating electromagnetic noise. This electromagnetic noise is transmitted to the passenger compartment through the vehicle's structural and air paths, affecting the passenger experience. Some existing technologies use methods such as fine-tuning the shape of the motor air gap and thickening the stator yoke to reduce electromagnetic noise, but the noise reduction effect is limited and the cost is relatively high.

[0004] It can be seen that the electromagnetic noise of the motor in the prior art is large, which affects the riding comfort of the electric vehicle passengers. Utility Model Content

[0005] The embodiments of the present application provide a motor rotor, a motor, a powertrain, and an electric vehicle, which solve the problem in the prior art that the electromagnetic noise of the motor is high and affects the riding comfort of the electric vehicle passengers.

[0006] A first aspect of an embodiment of the present application provides a motor rotor, comprising a rotor core and a magnetic assembly, wherein the magnetic assembly is embedded within the rotor core, located between the inner and outer walls thereof. The magnetic assembly comprises n pairs of magnetic units spaced apart circumferentially along the rotor core, where n is an integer greater than or equal to 2, each magnetic unit pair comprising two magnetic units, each magnetic unit comprising at least one permanent magnet and a permanent magnet slot corresponding to the at least one permanent magnet, the permanent magnet slots being disposed in the rotor core, and each permanent magnet being disposed within a corresponding permanent magnet slot.

[0007] In which, at least one permanent magnet has a first surface and a second surface arranged opposite to each other along its magnetization direction. In at least some magnetic units, the first surface and / or the second surface of at least one permanent magnet is configured as a curved surface, the curved surface has at least one curved surface, and a protrusion is formed at the position of at least one curved surface.

[0008] In the motor rotor provided by the present application, at least part of the permanent magnets has a first surface and a second surface arranged in opposite directions along its magnetization direction. The magnetization direction is the direction of the magnetic field of the permanent magnet, which determines the N pole (North Pole) and S pole (South Pole) of the permanent magnet. The first surface and the second surface are surfaces corresponding to the two magnetization directions of the permanent magnet. At least one of the first surface and the second surface is used as a trimming surface, and the trimming surface has a curved surface, and a protrusion is formed at the position of the curved surface. On the one hand, the provision of the curved surface can change the magnetic flux direction of the permanent magnet, thereby changing the air gap magnetic field between the rotor and the stator, reducing torque pulsation, that is, reducing the fluctuation of the electromagnetic force as the rotor rotates. Furthermore, the vibration of the motor stator and the vibration of the air around the motor are weakened, thereby reducing electromagnetic noise. On the other hand, trimming the surface of the permanent magnet increases the design parameters of the motor. In the motor design process, the shape, size, number, curvature and other parameters of the curved surface can be flexibly adjusted to continuously optimize the motor until the ideal noise reduction effect is achieved.

[0009] It can be seen that the motor rotor provided in the embodiment of the present application can reduce motor noise and improve the riding comfort of electric vehicle passengers.

[0010] In a possible implementation, the ratio of the thickness of each protrusion on the arc-trimming surface to the minimum thickness of the permanent magnet where it is located is less than or equal to 0.5, and the minimum thickness of the permanent magnet is the minimum distance between the first surface and the second surface along its magnetization direction.

[0011] By adopting the above solution, the amount of permanent magnets used can be reduced while ensuring the noise reduction effect, thereby reducing the production and processing costs of the motor.

[0012] In a possible implementation, the projection of each arc-shaped surface of the arc-trimming surface on the first plane is a circular arc line, an elliptical arc line, or a quadratic curve, wherein the first plane is perpendicular to the axis of the rotor core.

[0013] By adopting the above solution, each arc surface of the arc-trimming surface can be a circular arc surface, an elliptical arc surface or a quadratic curved surface. These shapes are relatively regular and have low design and processing difficulty.

[0014] In a possible implementation, the arc-trimming surface has an arc-shaped surface, both ends of the arc-shaped surface along its bending direction are respectively connected to the two side surfaces of the permanent magnet where it is located, and the protrusion formed at the position of the arc-shaped surface is an arc-shaped protrusion.

[0015] In one possible implementation, the at least one permanent magnet of the magnetic unit includes two first permanent magnets, which are symmetrically arranged in a V shape along the center line of the magnetic unit. The first surface and / or the second surface of the first permanent magnet are configured as arc-trimmed surfaces.

[0016] In one possible implementation, the relationship between the thickness of each protrusion on the arc-trimmed surface of the first permanent magnet and the corresponding minimum thickness of the first permanent magnet satisfies the following: 0.1H11 ≤ H12 ≤ 0.4H11, where H12 is the thickness of the protrusion and H11 is the corresponding minimum thickness of the first permanent magnet. This range is an empirical value derived from simulations and can achieve good noise reduction.

[0017] In one possible implementation, the magnetic unit having the first permanent magnet further includes two second permanent magnets. The two second permanent magnets are symmetrically arranged in a V-shape along the centerline of the corresponding magnetic unit. Along the centerline of the magnetic unit, the second permanent magnets are arranged on the side of the first permanent magnet facing the inner wall surface of the rotor core. The first surface and / or the second surface of the second permanent magnet are configured as arc-trimmed surfaces.

[0018] In one possible implementation, the relationship between the thickness of each protrusion on the arc-trimmed surface of the second permanent magnet and the corresponding minimum thickness of the second permanent magnet satisfies the following condition: H22 ≤ 0.1H21, where H22 is the thickness of the protrusion and H21 is the corresponding minimum thickness of the second permanent magnet. This range is an empirical value derived from simulations and can achieve optimal noise reduction.

[0019] In one possible implementation, each permanent magnet slot has a first slot wall and a second slot wall arranged at intervals along the magnetization direction of the corresponding permanent magnet, the gap between the first slot wall and the first surface of the permanent magnet is less than 0.1 mm, and the gap between the second slot wall and the second surface of the permanent magnet is less than 0.1 mm.

[0020] With the above solution, it can be understood that the slot wall and the surface of the permanent magnet 6 are fitted with a clearance. When the first surface 63 and / or the second surface 64 are set as the arc-shaped surface 65, the corresponding first slot wall 71 and / or the second slot wall 72 are also set as corresponding arc-shaped surfaces, and the permanent magnet 6 can be smoothly installed into the corresponding permanent magnet slot 7.

[0021] In a possible implementation, at least a portion of the outer wall surface of the rotor core is configured as a curved wall surface, the curved wall surface has at least one curved surface, and a protrusion or a recess is formed at the position of the at least one curved surface.

[0022] By adopting the above solution, arcs are repaired on the outer wall surface of the rotor core, which increases the design parameters of the motor, can further optimize the motor and reduce noise.

[0023] In one possible implementation, the rotor core includes a plurality of rotor core segments sequentially arranged along the axis of the rotor core, each rotor core segment is embedded with a magnetic assembly, and the magnetic assemblies on at least two rotor core segments are staggered along the circumference of the rotor core.

[0024] A second aspect of an embodiment of the present application provides a motor, comprising a motor stator and a motor rotor provided by the above-mentioned first aspect and any possible implementation thereof, wherein the motor stator and the motor rotor are coaxially arranged.

[0025] The motor provided in the embodiment of the present application has low operating noise, which can reduce the noise in the passenger compartment of an electric vehicle and improve riding comfort.

[0026] A third aspect of an embodiment of the present application provides a powertrain, comprising a gearbox, a drive shaft, and the motor provided in the second aspect above, wherein the gearbox is transmission-connected to the motor rotor of the motor via the drive shaft.

[0027] The powertrain provided in the embodiment of the present application can reduce noise in the passenger compartment of an electric vehicle and improve riding comfort.

[0028] The fourth aspect of the embodiment of the present application further provides an electric vehicle, comprising a body, wheels and the powertrain provided by the third aspect above, wherein the powertrain is arranged on the body and is used to drive the wheels.

[0029] The electric vehicle provided in the embodiment of the present application has low driving noise and high comfort. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a schematic structural diagram of an electric vehicle according to an embodiment of the present application;

[0031] Figure 2 This is a structural block diagram of an electric vehicle according to an embodiment of the present application;

[0032] Figure 3 This is a schematic diagram of the structure of the powertrain of an embodiment of the present application;

[0033] Figure 4a This is a schematic diagram of the structure of the motor according to the embodiment of the present application;

[0034] Figure 4b This is a schematic diagram of the air gap structure of the motor according to an embodiment of the present application;

[0035] Figure 5 This is a schematic diagram of the three-dimensional structure of the motor rotor according to an embodiment of the present application;

[0036] Figure 6 This is a schematic diagram of the exploded structure of the motor rotor according to an embodiment of the present application;

[0037] Figure 7 Schematic diagram of the three-dimensional structure of the rotor core segment in the motor rotor according to an embodiment of the present application;

[0038] Figure 8 This is a schematic diagram of the exploded structure of the rotor core segment of the motor in the embodiment of the present application;

[0039] Figure 9 This is a schematic diagram of the end surface structure of the motor rotor according to an embodiment of the present application;

[0040] Figure 10 This is a schematic structural diagram of a permanent magnet slot in a motor rotor according to an embodiment of the present application;

[0041] Figures 11a to 11f This is a schematic diagram of the arc-trimmed surface structure of the permanent magnet in the motor rotor according to an embodiment of the present application;

[0042] Figure 12 This is a side structural diagram of the second permanent magnet in the motor rotor according to an embodiment of the present application;

[0043] Figures 13a to 13g This is a schematic diagram of the layout of permanent magnets in the motor rotor according to an embodiment of the present application;

[0044] Figure 14a Schematic diagram of magnetic field distribution of permanent magnets in a motor;

[0045] Figure 14b This is a schematic diagram of the magnetic field distribution of the permanent magnet in the motor according to the embodiment of the present application;

[0046] Figure 15a This is a torque ripple simulation diagram of a motor;

[0047] Figure 15b This is a torque ripple simulation diagram of the motor according to an embodiment of the present application;

[0048] Figure 16 This is the noise response curve of the motor.

[0049] Description of reference numerals:

[0050] 100 - electric vehicle; 11 - body; 12 - wheels; 13 - battery module; 14 - transmission;

[0051] 200-powertrain; 21-gearbox; 22-drive shaft;

[0052] 300-motor; 3-motor stator; 31-base; 32-stator core; 320-stator slot; 33-stator winding;

[0053] 400-motor rotor;

[0054] 4- rotor core; 40- inner wall surface; 41- outer wall surface; 41A- arc-trimmed wall surface; 411- arc-shaped surface; 42- rotor core segment;

[0055] 5-magnetic assembly; 51-magnetic unit pair; 511-magnetic unit;

[0056] 6-permanent magnet; 61-first permanent magnet; 62-second permanent magnet; 63-first surface; 64-second surface;

[0057] 65-curved surface; 651-arc-shaped surface; 652-convex; 66-first side surface; 67-second side surface; 68-third side surface; 69-fourth side surface;

[0058] 7-permanent magnet slot; 71-first slot wall; 72-second slot wall;

[0059] 82-motor shaft; 83-shaft cover;

[0060] M-first plane; O-axis; Q-center line; X-magnetization direction. DETAILED DESCRIPTION

[0061] The following specific embodiments illustrate the implementation of the present application. Those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. Although the description of the present application will be introduced in conjunction with some embodiments, this does not mean that the features of this application are limited to the implementation. On the contrary, the purpose of introducing the application in conjunction with the implementation is to cover other options or modifications that may be extended based on the claims of the present application. In order to provide an in-depth understanding of the present application, the following description will contain many specific details. The present application can also be implemented without using these details. In addition, in order to avoid confusion or blurring the focus of the present application, some specific details will be omitted in the description. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other unless there is a conflict.

[0062] It should be noted that in this specification, similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0063] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," "outer," "top," "bottom," and the like, indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended only to facilitate the description of this application and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limiting this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0064] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0065] In the description of this application, it should be noted that the term "perpendicular" in this application does not mean absolute perpendicularity. Approximate perpendicularity due to processing errors and assembly errors (for example, an angle of 89.9° between two structural features) is also within the scope of "perpendicular" in this application. The term "parallel" in this application does not mean absolute parallelism. Approximate parallelism due to processing errors and assembly errors (for example, an angle of 0.1° between two structural features) is also within the scope of "parallel" in this application. This application does not make any specific restrictions on this.

[0066] In order to make the objectives, technical solutions and advantages of this application clearer, the implementation methods of this application will be further described in detail below with reference to the accompanying drawings.

[0067] Most permanent magnet synchronous motors use an air gap structure, with an air gap between the motor rotor and the motor stator. When the motor rotor rotates, an air gap magnetic field is generated, which in turn generates electromagnetic force waves that vary with time and space, namely torque pulsation. This electromagnetic force wave causes the motor stator and housing to vibrate, and the vibration of the stator and housing causes the surrounding air to vibrate, causing electromagnetic noise. In electric vehicles, electromagnetic noise is transmitted to the passenger compartment through the vehicle structure path and air path, affecting the passenger experience. The present application provides a motor rotor, motor, powertrain and electric vehicle to reduce electromagnetic noise and improve the riding comfort of electric vehicle passengers.

[0068] The motor provided in this application can be used not only in electric vehicles, but also in mechanical equipment in other fields, such as washing machines, refrigerators, fans or water pumps, etc., and this application does not impose any restrictions.

[0069] See also Figures 1 to 3 , Figure 1 This is a schematic structural diagram of an electric vehicle according to an embodiment of the present application; Figure 2 This is a structural block diagram of an electric vehicle according to an embodiment of the present application; Figure 3 This is a schematic diagram of the structure of the powertrain of an embodiment of the present application.

[0070] like Figures 1 to 3As shown, an embodiment of the present application provides an electric vehicle 100, that is, a new energy vehicle with electric drive as a power source. The electric vehicle 100 can be a pure electric vehicle, or a hybrid vehicle that combines fuels such as hydrogen and fuel with electricity, etc., and this application does not impose any restrictions on this. The electric vehicle 100 includes a body 11, wheels 12 and a powertrain 200. The powertrain 200 is arranged on the body 11 and is used to drive the wheels 12. In one possible implementation, the electric vehicle 100 may also include a transmission device 14 and a battery module 13. The wheels 12 are connected to the powertrain 200 through the transmission device 14. In one possible implementation, the battery module 13 is fixed to the body 11 and is used to supply power to the powertrain 200.

[0071] The specific structure of the powertrain 200 is not limited. In one possible implementation, the powertrain 200 includes a gearbox 21, a drive shaft 22, and a motor 300. The gearbox 21 is connected to the stator and rotor 400 of the motor 300 via the drive shaft 22. For example, the driving force output by the motor 300 can be transmitted to the gearbox 21 via the drive shaft 22. The gearbox 21 is connected to the wheels 12 via the transmission device 14. The gearbox 21 can change the driving force according to the different driving conditions of the electric vehicle 100, driving the wheels 12 to rotate at different speeds, thereby achieving variable speed driving of the electric vehicle 100.

[0072] In one possible implementation, the powertrain 200 may further include a motor controller (not shown), which is configured to receive direct current (DC) power from the battery module 13 and convert the DC power into AC power for transmission to the motor 300. After receiving the AC power, the motor 300 converts the electrical energy into mechanical energy and transmits the mechanical energy to the gearbox 21. In actual scenarios, the powertrain 200 of the electric vehicle 100 may include more or fewer structures than those shown in the drawings, and this application does not limit this.

[0073] See also Figures 4a to 4b , Figure 4a This is a schematic diagram of the structure of the motor according to the embodiment of the present application; Figure 4b Schematic diagram of the air gap structure of the motor according to an embodiment of the present application.

[0074] like Figures 4a to 4b As shown, the motor 300 includes a motor stator 3 and a motor rotor 400, and the motor stator 3 and the motor rotor 400 are coaxially sleeved. Specifically, the motor 300 may further include a motor shaft 82, the motor rotor 400 is sleeved on the motor shaft 82 and fixed relative to the motor shaft 82, and the motor stator 3 is sleeved outside the motor rotor 400. Figure 4bAs shown, there is an air gap between the motor rotor 400 and the motor stator 3, or it can be understood that there is a gap between the two. When the motor 300 is operating, the motor stator 3 applies a rotating magnetic field to the motor rotor 400, causing the motor rotor 400 to rotate relative to the motor stator 3, thereby driving the motor shaft 82 to rotate. The motor 300 outputs power through the motor shaft 82. Exemplarily, the motor shaft 82 can be connected to the transmission shaft 22 to transmit power to the gearbox 21. The transmission shaft 22 can also be understood as the input shaft of the gearbox 21.

[0075] It should be noted that the specific structure of the motor stator 3 is not limited. Figures 4a to 4b As shown, in a possible implementation, the motor stator 3 includes a base 31, a stator core 32 and a stator winding 33. The stator core 32 is part of the motor magnetic circuit and is mainly composed of annular punchings such as silicon steel sheets. The stator winding 33 is installed in the stator core 32 and is an integral part of the motor 300 circuit. Specifically, the stator winding 33 is a coil structure wound on the stator core 32. Passing alternating current through the stator winding 33 can generate a rotating magnetic field. The base 31 is used to install and fix the stator core 32 and the stator winding 33, and can be regarded as the shell of the motor 300.

[0076] like Figure 4b As shown, in one possible implementation, the stator core 32 includes a plurality of stator slots 320 arranged along its circumference. The plurality of stator slots 320 are closely arranged, serrated protrusion structures, and are used to enhance the stability of the magnetic field of the motor 300. In addition, the stator slots 320 can also help the motor 300 control the speed and adjust the output power. It should be noted that the specific number of stator slots 320 is not limited, and can be specifically designed and optimized according to parameters such as the size of the motor 300. In one possible implementation, 54 stator slots 320 are provided in the motor stator 3.

[0077] The stator slots 320 are one of the important structures of the motor 300, but they are also one of the sources of noise in the motor 300. Those skilled in the art will understand that the torque pulsation of the motor 300 is mainly composed of ripple torque and cogging torque. Ripple torque is the torque generated by the harmonics of the air gap magnetic flux density. As the speed of the functional components of the motor rotor 400 increases, the high-frequency components of the air gap magnetic flux waveform also increase, thereby generating high-frequency noise. Cogging torque is the torque generated by the periodic interaction between the rotor magnetic field and the stator slots 320. Cogging torque can be measured by the average tooth force of the motor stator 3 (i.e., the average electromagnetic force exerted on the stator slots 320 when the motor 300 is operating). The greater the average tooth force, the greater the cogging torque and the greater the torque pulsation. Reasonable design of the parameters of the motor 300 can reduce the cogging torque, the ripple torque, and the harmonic magnetic field of the air gap magnetic field, thereby reducing torque pulsation and lowering the operating noise of the motor 300.

[0078] It should be noted that Figure 4a and Figure 4b This is only an illustration and does not limit the specific shape and structure of the motor 300. In other possible implementations, the motor 300 may further include more or fewer structures than those shown in the figure.

[0079] See also Figures 5 to 10 , Figure 5 This is a schematic diagram of the three-dimensional structure of the motor rotor according to an embodiment of the present application; Figure 6 This is a schematic diagram of the exploded structure of the motor rotor according to an embodiment of the present application; Figure 7 Schematic diagram of the three-dimensional structure of the rotor core segment in the motor rotor according to an embodiment of the present application; Figure 8 This is a schematic diagram of the exploded structure of the rotor core segment of the motor in the embodiment of the present application; Figure 9 This is a schematic diagram of the end surface structure of the motor rotor according to an embodiment of the present application; Figure 10 This is a schematic structural diagram of the permanent magnet slots in the motor rotor according to an embodiment of the present application.

[0080] like Figures 5 and 6 As shown, the motor rotor 400 includes a rotor core 4 and a magnetic assembly 5, and the magnetic assembly 5 is embedded in the rotor core 4, at a position between its inner wall surface 40 and outer wall surface 41. It can be understood that the rotor core 4 is sleeved outside the motor shaft 82. Therefore, the rotor core 4 is an annular structure, and the inner wall surface 40 and the outer wall surface 41 of the rotor core 4 are the inner wall surface and the outer wall surface of the annular structure. In a possible implementation, the motor rotor 400 also includes two shaft covers 83, and the two shaft covers 83 are respectively arranged at both ends of the rotor core 4 along the axis O of the rotor core 4, and are sleeved on the motor shaft 82. The shaft cover 83 is used to fix and protect the rotor core 4 to prevent the rotor core 4 from being damaged when rotating. The shaft cover 83 may also be omitted in the motor rotor 400, and this application does not impose any restrictions on this.

[0081] In one possible implementation, the rotor core 4 includes a plurality of rotor core segments 42 sequentially arranged along the axis O of the rotor core 4 , each of which is embedded with a magnetic component 5 . Alternatively, it can be understood that the rotor core 4 is axially arranged as a segmented structure, with each segment being provided with a corresponding magnetic component 5 . The specific number of rotor core segments 42 is not limited. For example, Figure 5 and Figure 6 The illustrated rotor core 4 includes six rotor core segments 42. In other possible scenarios, the number of rotor core segments 42 can be two, three, eight, or the like. Alternatively, the rotor core 4 may not be segmented, i.e., the entire rotor core 4 may include only one rotor core segment 42. Some rotor core segments 42 may not be provided with magnetic assemblies 5, and the structures of magnetic assemblies 5 in different rotor core segments 42 may be the same or different, and this application does not impose any restrictions on this.

[0082] Furthermore, if Figures 7 to 9 As shown, the magnetic assembly 5 includes n magnetic unit pairs 51 spaced apart along the circumference of the rotor core 4, where n is an integer greater than or equal to 2. Each magnetic unit pair 51 includes two magnetic units 511, each magnetic unit 511 including at least one permanent magnet 6 and a permanent magnet slot 7 corresponding to the at least one permanent magnet 6. The permanent magnet slot 7 is provided in the rotor core 4, and each permanent magnet 6 is disposed in a corresponding permanent magnet slot 7.

[0083] Or it can be understood that the magnetic assembly 5 includes n magnetic unit pairs 51, 2n magnetic units 511, each magnetic unit 511 has at least one permanent magnet 6, and the permanent magnet 6 is installed in the permanent magnet slot 7 corresponding to it. The specific value of n is not limited, for example, it can be 2, 3, 4, etc. One or more permanent magnets 6 can be set in each magnetic unit 511, and this application does not limit this. For example, Figures 7 to 9 The rotor core segments 42 are provided with three magnetic unit pairs 51 (n=3), each magnetic unit pair 51 including two magnetic units 511, for a total of six magnetic units 511. Each magnetic unit 511 is provided with four permanent magnets 6, and the number of permanent magnet slots 7 corresponds to the number of permanent magnets 6. For example, each rotor core segment 42 of the rotor core 4 can be formed by laminating a plurality of rotor punchings (e.g., silicon steel sheets), each having slots. When the rotor punchings are laminated to form the rotor core segments 42, these slots form the permanent magnet slots 7.

[0084] It is understandable that each permanent magnet 6 has an N pole (North Pole) and an S pole (South Pole), and the present application does not limit the magnetic pole arrangement of each permanent magnet 6 in the magnetic assembly 5. In one possible implementation, the magnetic pole distributions of the two magnetic units 511 in the same magnetic unit pair 51 are different. Therefore, the magnetic assembly 5 cannot be regarded as a plurality of identical magnetic units 511 arranged along the circumference of the motor stator 3, but rather a plurality of magnetic unit pairs 51 arranged along the circumference of the motor stator 3. For example, Figure 7 Although the permanent magnets 6 in the two magnetic units 511 in the illustrated magnetic unit pair 51 appear to have the same structure and corresponding positions, the magnetic poles of the two corresponding permanent magnets 6 are arranged in opposite directions. For example, in the figure, permanent magnet A and permanent magnet A' are positioned in corresponding directions (permanent magnet A' can be regarded as magnet A rotating along the circumference of the rotor core 4), and the magnetic pole arrangement of permanent magnet A in the counterclockwise direction is NS, corresponding to the magnetic pole arrangement of permanent magnet A' in the other magnetic unit 511 in the counterclockwise direction is SN. It should be noted that the magnetic pole distribution of the permanent magnet 6 in the drawings of this application is for illustration only and does not limit the motor rotor 400.

[0085] Furthermore, if Figures 7 and 8As shown, each permanent magnet 6 has a first surface 63 and a second surface 64 arranged opposite to each other along its magnetization direction X. In at least some magnetic units 511, the first surface 63 and / or the second surface 64 of at least one permanent magnet 6 is configured as a curved surface 65, and the curved surface 65 has at least one curved surface 651, and a protrusion 652 is formed at the position of at least one curved surface 651.

[0086] The magnetization direction X is the direction of the magnetic field of the permanent magnet 6, which determines the N pole (North Pole) and S pole (South Pole) of the permanent magnet 6. The first surface 63 and the second surface 64 are surfaces corresponding to the two magnetization directions of the permanent magnet 6. When the permanent magnet 6 is a block structure, the thickness direction of the permanent magnet 6 is the magnetization direction X (the thickness direction of each permanent magnet 6 is perpendicular to the axis O of the rotor core 4, Figure 9 The direction where the thickness H1 of the first permanent magnet 61 lies is its thickness direction, and the direction where the thickness H2 of the second permanent magnet 62 lies is its thickness direction).

[0087] In at least a portion of the permanent magnet 6, at least one of the first surface 63 and the second surface 64 is used as a curved surface 65. The curved surface 65 has a curved surface 651, and a protrusion 652 is formed at the position of the curved surface 651. On the one hand, the provision of the curved surface 651 can change the direction of the magnetic flux of the permanent magnet 6, thereby changing the air gap magnetic field between the rotor and the stator, reducing torque pulsation, that is, reducing the fluctuation of the electromagnetic force as the rotor rotates. Furthermore, the vibration of the motor stator 3 and the vibration of the air around the motor 300 are weakened, thereby reducing electromagnetic noise. On the other hand, the curved surface of the permanent magnet 6 increases the design parameters of the motor 300. In the motor design process, the shape, size, number, curvature and other parameters of the curved surface 651 can be flexibly adjusted to continuously optimize the motor 300 until the ideal noise reduction effect is achieved. It can be seen that the motor rotor 400 provided in the embodiment of the present application can reduce the electromagnetic noise of the motor and improve the comfort of the passengers in the vehicle.

[0088] It should be noted that any permanent magnet 6 on any rotor core segment 42 can be provided with an arc-trimming surface 65 or not, and the present application does not limit the number and position of the permanent magnets 6 provided with the arc-trimming surface 65. In one possible implementation, all permanent magnets 6 in the rotor core 4 are provided with an arc-trimming surface 65, so that the overall magnetic field distribution of the rotor core 4 can be uniformly changed, and the arc-trimming surface 65 of each permanent magnet 6 increases the designable parameters of the motor 300, which can achieve a better noise reduction effect. In each permanent magnet 6, the first surface 63 can be set as the arc-trimming surface 65, the second surface 64 can be set as the arc-trimming surface 65, or both surfaces can be provided with the arc-trimming surface 65, and the present application does not limit this. Figures 7 and 8As shown, in one possible implementation, the first surface 63 of each permanent magnet 6 is configured as a trimmed surface 65. The first surface 63 is the surface of each permanent magnet 6 facing the outer wall 41. It can also be understood that the surface of each permanent magnet 6 facing the motor stator 3 is configured as the trimmed surface 65.

[0089] like Figures 9 and 10 As shown, in one possible implementation, each permanent magnet slot 7 has: a first slot wall 71 and a second slot wall 72 spaced apart along the magnetization direction X of the corresponding permanent magnet 6, the gap between the first slot wall 71 and the first surface 63 of the permanent magnet 6 is less than 0.1 mm, and the gap between the second slot wall 72 and the second surface 64 of the permanent magnet 6 is less than 0.1 mm. It can be understood that the slot wall and the surface of the permanent magnet 6 are matched through a gap. When the first surface 63 and / or the second surface 64 is set as a trimmed arc surface 65, the corresponding first slot wall 71 and / or second slot wall 72 is also set as a corresponding arc surface, and the permanent magnet 6 can be smoothly installed into the corresponding permanent magnet slot 7. In some possible embodiments, the gap between the first slot wall 71 and the first surface 63 of the permanent magnet 6 can be greater than or equal to 0.1 mm, and the gap between the second slot wall 72 and the second surface 64 of the permanent magnet 6 can also be greater than or equal to 0.1 mm. This application is not limited to this.

[0090] It should be noted that the present application does not limit the specific shape and size of the arc-trimming surface 65. Several possible scenarios are described below by way of example.

[0091] See also Figures 11a to 12 , Figures 11a to 11f This is a schematic diagram of the arc-trimmed surface structure of the permanent magnet in the motor rotor according to an embodiment of the present application; Figure 12 This is a side structural schematic diagram of the second permanent magnet in the motor rotor according to an embodiment of the present application.

[0092] like Figures 11a to 11c 、 Figure 12 As shown, in a possible implementation, the arc-shaped surface 65 has an arc-shaped surface 651. Figure 11a 、 Figure 11b 、 Figure 12 As shown, in a possible implementation, the two ends of the arc surface 651 along its bending direction are respectively connected to the two side surfaces of the permanent magnet 6 where it is located, and the protrusion 652 formed at the position of the arc surface 651 is an arc-shaped protrusion. Specifically, the permanent magnet 6 has a first side surface 66 and a second side surface 67 arranged opposite to each other in its length direction, and a third side surface 68 and a fourth side surface 69 arranged opposite to each other in its width direction. The length direction of each permanent magnet 6 is perpendicular to the axis O of the rotor core 4, and the width direction is parallel to the axis O of the rotor core 4. For example, Figure 8 、 Figure 9 、 Figure 11a As shown, the length direction of the first permanent magnet 61 is the direction of its length L11, L11 is perpendicular to the axis O, and the width direction of the first permanent magnet 61 is the direction of its width L12, L12 is parallel to the axis O. The length direction of the second permanent magnet 62 is the direction of its length L21, L21 is perpendicular to the axis O, and the width direction is the direction of its width L22, L22 is parallel to the axis O. In one possible implementation, the two ends of the arc surface 651 along its bending direction are respectively connected to the two side surfaces in the length direction of the permanent magnet 6, namely the first side surface 66 and the second side surface 67. In some possible implementations, the two ends of the arc surface 651 along its bending direction may also be connected to the third side surface 68 and the fourth side surface 69, which is not limited in this application. As Figure 11c As shown, in a possible implementation, both ends of the arc surface 651 along its bending direction may not be connected to both side surfaces of the permanent magnet 6, or may only be connected to one side surface, which is not limited in the present application.

[0093] like Figure 11e 、 Figure 11f As shown, the arc-shaped surface 65 may also have multiple arc-shaped surfaces 651, for example, two. The multiple arc-shaped surfaces 651 may be arranged in a connected manner, for example Figure 11f , can also be set at intervals, for example Figure 11e .

[0094] like Figures 11a to 11c As shown, in a possible implementation, the projection of each arc surface 651 of the arc-trimming surface 65 on the first plane M is: a circular arc line or an elliptical arc line or a quadratic curve. The first plane M is perpendicular to the axis O of the rotor core 4. Or it can be understood that each arc surface 651 of the arc-trimming surface 65 can be a circular arc surface, an elliptical arc surface or a quadratic surface. These shapes are relatively regular and have low design and processing difficulty. In other alternative embodiments, the arc surface 651 of the arc-trimming surface 65 can also be an irregular arc surface 651 or a surface similar to an arc surface 651, etc., and this application does not limit this. For example, Figure 11d The arc surface 651 includes a straight surface and two curved surfaces connected at both ends of the straight surface. The straight surface and the two curved surfaces together form a shape similar to the arc surface 651. It is understood that the shape of the arc surface 651 of the arc-trimming surface 65 can be determined according to actual needs and is not limited in this application.

[0095] like Figure 11a 、 Figure 12As shown, in a possible implementation, the ratio of the thickness of the protrusion 652 of the arc-trimming surface 65 to the minimum thickness of the permanent magnet 6 on which it is located is less than or equal to 0.5, such as 0.1, 0.2, 0.35, 0.5, etc. The minimum thickness of the permanent magnet 6 is the minimum distance between the first surface 63 and the second surface 64 along the magnetization direction X thereof, such as the height of the side wall of the permanent magnet 6. Specifically, Figure 11a The minimum thickness of the middle permanent magnet 6 is H11, the thickness of the protrusion 652 is H12, H1=H11+H12, H12≤0.5H11. Figure 12 The minimum thickness of the middle permanent magnet 6 is H21, and the thickness of the protrusion 652 is H22, H2=H21+H22, H22≤0.5H21.

[0096] When the ratio of the thickness of the protrusion 652 at the location of the arc-repairing surface 65 to the minimum thickness of the permanent magnet 6 is less than 0.5, the amount of the permanent magnet 6 can be reduced while ensuring the noise reduction effect. It is understandable that in the prior art, the permanent magnet 6 is a rectangular parallelepiped structure, and both surfaces of the permanent magnet 6 in the magnetization direction X are flat (refer to FIG. Figure 14a ), compared with the traditional solution, the present application sets a trimming surface 65 on the permanent magnet 6, and controls the ratio of the thickness of the protrusion 652 at the position of the trimming surface 65 to the minimum thickness of the permanent magnet 6 where it is located to be below 0.5, which can reduce the amount of permanent magnet 6 while ensuring the same output power and torque (the proportion of permanent magnet 6 in the rotor core 4 is reduced, which can be specifically measured by the cross-sectional area of the permanent magnet 6), and can reduce the production and processing costs of the motor 300.

[0097] like Figure 7 、 Figure 9 As shown, in one possible implementation, the magnetic unit 511 includes two first permanent magnets 61, and the two first permanent magnets 61 are symmetrically arranged in a V shape along the center line Q of the magnetic unit 511. The center line Q of the magnetic unit 511 intersects with the axis O of the rotor core 4 and divides the rotor core 4 where the magnetic unit 511 is located into two symmetrical parts. Furthermore, the first surface 63 and / or the second surface 64 of the first permanent magnet 61 are configured as a trimmed surface 65. In one possible embodiment, the first surface 63 of the first permanent magnet 61 is configured as a trimmed surface 65, and the first surface 63 faces the outer wall surface 41 of the rotor core 4, that is, toward the motor stator 3. In some possible implementations, the second surface 64 of the first permanent magnet 61 can also be configured as a trimmed surface 65, or both surfaces can be configured as trimmed surfaces 65, and this application does not impose any restrictions on this.

[0098] like Figure 11aAs shown in FIG. 1 , in one possible implementation, the relationship between the thickness H12 of each protrusion 652 on the arc-trimmed surface 65 of the first permanent magnet 61 and the corresponding minimum thickness H11 of the first permanent magnet 61 satisfies the following: 0.1H11 ≤ H12 ≤ 0.4H11, i.e., the ratio of H12 to H11 is within the range of 0.1 to 0.4. This range is an empirical value derived from simulations and can achieve good noise reduction.

[0099] like Figure 7 、 Figure 9 As shown, in one possible implementation, the magnetic unit 511 having a first permanent magnet 61 further includes two second permanent magnets 62. The two second permanent magnets 62 are symmetrically arranged in a V-shape along the centerline Q of the corresponding magnetic unit 511. Along the centerline Q of the magnetic unit 511, the second permanent magnets 62 are arranged on the side of the first permanent magnet 61 facing the inner wall surface 40 of the rotor core 4. Furthermore, the first surface 63 and / or the second surface 64 of the second permanent magnet 62 are configured as a curved surface 65. In one possible implementation, the first surface 63 of the second permanent magnet 62 is configured as a curved surface 65, with the first surface 63 facing the outer wall surface 41 of the rotor core 4, that is, toward the motor stator 3. It can be understood that the first permanent magnet 61 and the second permanent magnet 62 in the magnetic unit 511 form a "double V structure." In this "double V structure," the surface of each permanent magnet 6 facing the outer wall surface 41 of the rotor core 4 is configured as a curved surface 65.

[0100] like Figure 12 As shown, in a possible implementation, the relationship between the thickness H22 of each protrusion 652 in the arc-trimmed surface 65 of the second permanent magnet 62 and the corresponding minimum thickness H21 of the second permanent magnet 62 satisfies: H22≤0.1H21. This range is an empirical value calculated by simulation and can achieve better noise reduction effect.

[0101] It is understandable that the design parameters of the motor 300 include multiple aspects, such as the material and size of each component in the motor 300. As far as the motor rotor 400 is concerned, the length, diameter, number of segments, material, parameters of the permanent magnet 6 and the permanent magnet slot 7 of the rotor core 4 are crucial. Among them, the parameters of the permanent magnet 6 include the distribution of the permanent magnet 6 in the rotor core 4, the size, material, position, angle, etc. of each permanent magnet 6, and the parameters of the permanent magnet slot 7 are set in conjunction with the permanent magnet 6. Specifically, the type of the permanent magnet 6 can be a sintered magnet or a bonded magnet, and can be made of materials such as aluminum nickel cobalt, ferrite, neodymium iron boron or samarium cobalt. As Figure 9 As shown, the size of the permanent magnet 6 may include the length, width, thickness, angle, etc. of the permanent magnet 6 .

[0102] like Figure 5 、 Figure 8As shown, in one possible implementation, the total length of the rotor core 4 is S, the number of segments is x, and the width of the first permanent magnet 61 is L12, where L12 = S / x. Alternatively, it can be understood that the width of the first permanent magnet 61 is the same as the thickness of the rotor core segment 42. In some possible implementations, the width of the first permanent magnet 61 may also be different from the thickness of the rotor core segment 42, for example, smaller than the thickness of the rotor core segment 42, which is not limited in this application.

[0103] like Figure 9 As shown, in one possible implementation, the diameter of the rotor core 4 is D, the length of the first permanent magnet 61 is L11, the thickness is H1, 0.1D≤L11≤0.2D, 0.02D≤H1≤0.04D. In some possible implementations, L11 may be less than 0.1D or greater than 0.2D, and H1 may be less than 0.02D or greater than 0.04D, which is not limited in this application.

[0104] like Figure 5 、 Figure 8 As shown, in one possible implementation, the width of the second permanent magnet 62 is L22, where L22 = S / x, i.e., the width of the second permanent magnet 62 is the same as the thickness of the rotor core segment 42. In some possible implementations, the width of the second permanent magnet 62 may also be different from the thickness of the rotor core segment 42, for example, smaller than the thickness of the rotor core segment 42, which is not limited in this application.

[0105] like Figure 9 As shown, the second permanent magnet 62 has a length L21 and a thickness H2, and 0.15D≤L21≤0.3D, and 0.02D≤H2≤0.04D. In some possible implementations, L21 may be less than 0.15D or greater than 0.3D, and H2 may be less than 0.02D or greater than 0.04D, which is not limited in this application.

[0106] In the "double V structure," the two first permanent magnets 61 are symmetrical with respect to the centerline Q of the magnetic unit 511, and the two second permanent magnets 62 are also symmetrical with respect to the centerline Q. The angle α between the length direction of the first permanent magnet 61 and the centerline Q is α, and the angle β between the length direction of the second permanent magnet 62 and the centerline Q is β. In one possible implementation, 30° ≤ α ≤ 75°, and 30° ≤ β ≤ 75°. In some possible implementations, α and β may be less than 30° or greater than 75°, and this application does not impose any restrictions on this.

[0107] See also Figures 13a to 13g , Figures 13a to 13g This is a schematic diagram of the layout of permanent magnets in the motor rotor according to an embodiment of the present application.

[0108] like Figures 13a to 13bAs shown, in a possible implementation, the permanent magnets 6 can also be arranged in a "single V structure" in the rotor core 4, for example, only the first permanent magnet 61 ( Figure 13a ) or only the second permanent magnet 62 ( Figure 13b ).like Figures 13c to 13e As shown, the permanent magnets 6 can also be arranged in a "straight line structure" in the rotor core 4. Figure 13c 5 magnetic unit pairs 51 are shown in FIG. Figure 13d 、 Figure 13e 2 magnetic unit pairs 51 are shown in FIG. Figure 13c 、 Figure 13d The magnetization direction X of the permanent magnets 6 is distributed along the radial direction of the rotor core 4, that is, radial arrangement. Figure 13e The magnetization direction X of the permanent magnets 6 is distributed along the tangential direction of the rotor core 4, that is, the permanent magnets 6 are arranged tangentially. Figure 13f As shown, the permanent magnets 6 can also be arranged in a mixed "straight structure" and "single V structure" in the rotor core 4, such as Figure 13g As shown, it can also be a mixed arrangement of radial and tangential types in the "straight-line structure", etc., which will not be listed one by one in this application.

[0109] like Figures 7 and 8 As shown in FIG. 1 , in a possible implementation, at least a portion of the outer wall surface 41 of the rotor core 4 is configured as a trimmed wall surface 41A. The trimmed wall surface 41A has at least one arcuate surface 411, and a protrusion (protruding from the outer wall surface 41 of the rotor core) or a recess (recessed into the outer wall surface 41 of the rotor core) is formed at the location of the arcuate surface 411. It can be understood that trimming the outer wall surface 41 of the rotor core 4 increases the design parameters of the motor 300, can further optimize the motor 300, and reduce noise. Figure 5 As shown, in one possible implementation, the outer wall surface 41 of each rotor core segment 42 of the rotor core 4 is configured as an arc-trimming wall surface 41A. In some possible implementations, only the outer wall surface 41 of a portion of the rotor core segments 42 may be configured as an arc-trimming wall surface 41A. In each rotor core segment 42, all outer wall surfaces 41 along its circumference may be configured as arc-trimming wall surfaces 41A, or only a portion of the outer wall surfaces 41 may be configured as arc-trimming wall surfaces 41A, and this application does not impose any restrictions on this. The protrusion in the arc-trimming wall surface 41A may be an arc-shaped surface 411, an elliptical surface, a quadratic curve surface or an irregular curved surface, etc., and this application does not impose any restrictions on this. One or more arc-shaped surfaces 411 may be provided on the arc-trimming wall surface 41A, and this application does not impose any restrictions on this. As Figures 7 and 8As shown, in one possible implementation, a plurality of arcuate surfaces 411 are provided on the arc-trimming wall surface 41A, and the plurality of arcuate surfaces 411 form a plurality of protrusions and a plurality of recesses arranged alternately on the outer wall surface 41 of the rotor core. In some possible implementations, the plurality of arcuate surfaces on the arc-trimming wall surface 41A may all be protrusions or all be recesses, and this application is not limited thereto.

[0110] like Figure 5 As shown, in one possible implementation, the magnetic components 5 on at least two rotor core segments 42 are staggered along the circumference of the rotor core 4. That is, the electrode rotor adopts a segmented oblique pole structure, and different rotor core segments 42 are twisted by a certain angle, which can eliminate unbalanced magnetic pull and low-order noise. In the rotor core 4, any two adjacent rotor core segments 42 can be staggered or aligned, and this application does not impose any restrictions on this. Any two adjacent rotor core segments 42 can be twisted clockwise or counterclockwise, and this application does not impose any restrictions on this. In one possible implementation, the rotor core 4 includes x rotor core segments 42, the motor stator 3 is provided with m stator tooth slots 320, and the maximum torsion angle in the rotor core 4 is γ, γ = 360 / m, or γ = 180 / m. Among them, γ can be the torsion angle between two adjacent or non-adjacent rotor core segments 42. For example, as Figure 5 As shown, the rotor core 4 includes six rotor core segments 42, namely: v1, v2, v3, v4, v5, and v6. The six rotor core segments 42 are twisted in a V shape (the twisting direction between the three rotor core segments v1, v2, and v3 on the left is different from the twisting direction between the three rotor core segments v4, v5, and v6 on the right). Among them, the twisting angle between v1 and v4 is the largest, denoted as γ. Assuming that the motor stator 3 has 54 stator tooth slots 320 (m=54), then γ=360 / 54=6.67°, or γ=180 / 54=3.34°. In some possible implementations, γ can also be other values, such as 6°, 3°, 7°, etc., which are not limited in this application.

[0111] See also Figures 14a to 16 , Figure 14a Schematic diagram of magnetic field distribution of permanent magnets in a motor; Figure 14b This is a schematic diagram of the magnetic field distribution of the permanent magnet in the motor according to the embodiment of the present application; Figure 15a This is a torque ripple simulation diagram of a motor; Figure 15b This is a torque ripple simulation diagram of the motor according to an embodiment of the present application; Figure 16 This is the noise response curve of the motor.

[0112] To verify the contribution of this application solution to motor noise reduction, simulation experiments and other methods are used to compare this application solution with traditional solutions. The experimental data and comparison structure are as follows:

[0113] In this application, the design Figures 4a to 5 The motor 300 structure shown in FIG. 5 is characterized in that the number of teeth of the motor stator 3 is 54, the total length of the rotor core 4 is S=120 mm, the diameter is D=135.2 mm, and the number of segments is 6; the width L12 of the first permanent magnet 61 is 20 mm, the length L11 is 17.5 mm, and the thickness H1 is 4.3 mm; the width L22 of the second permanent magnet 62 is 20 mm, the length L21 is 28 mm, and the thickness H2 is 4.1 mm.

[0114] like Figure 14b As shown, based on the above data, the first surface 63 of each permanent magnet 6 is set as a trimmed arc surface 65, adopting an arc surface structure, with both ends of the arc surface connected to the two side walls of the permanent magnet 6. Figure 14a As shown in the figure, under the condition that other parameters remain unchanged, a control group of the traditional scheme is set up, in which the permanent magnet adopts a rectangular parallelepiped structure and no arc-repairing surface is set. Figure 14a and Figure 14b It can be seen that the arc-trimmed surface changes the magnetic field distribution around the permanent magnet, and the air gap magnetic field between the motor rotor and the motor stator changes.

[0115] like Figures 15a to 15b As shown, Figure 15a The horizontal axis represents the electrical angle (the angle occupied by each magnetic unit pair of the motor on the inner circle of the motor stator), and the vertical axis represents the torque ripple of the traditional solution. Figure 15b Indicates the electrical angle, and the vertical axis indicates the torque ripple of the motor of this application. Figure 15a and Figure 15b It can be seen that compared with the traditional solution, the torque pulsation of the motor of the present application is reduced overall.

[0116] like Figure 16 As shown, Figure 16 The horizontal axis represents the frequency of the motor, the vertical axis represents the noise intensity, and the three curves are respectively the noise response simulation curve of the motor of the present application, the noise response simulation curve of the motor of the traditional solution, and the noise response simulation curve of the bench test of the present application (the motor bench test is to fix the motor on the bench and connect various instruments and equipment to simulate actual working conditions, and conduct comprehensive testing and evaluation of the motor.). By comparison, it can be seen that the noise response curve of the motor 300 of the present application is lower than that of the traditional solution as a whole.

[0117] As shown in Table 1 below, while ensuring sufficient output torque (the output torque of the motor 300 of the present application is greater than that of the traditional solution), the amount of permanent magnets used in the motor rotor 400 of the present application is reduced by 1.4%, the average tooth force of the motor stator 3 is reduced by 40.7%, and the torque pulsation is reduced by 31.9%.

[0118] Table 1

[0119] Traditional solutions This application Change <![CDATA[Usage of permanent magnet (mm 2 )]]> 360 355 -1.4％ Torque (Nm) 423.2 432.3 +2.1％ Torque ripple 1.2% (5.08Nm) 0.8% (3.46Nm) -31.9％ Average tooth force (N) 81 48 -40.7％

[0120] It will be appreciated by those skilled in the art that the motor easily excites noise peaks in the breathing mode (the motor breathing mode is an inherent characteristic of the stator, also known as the 0th order mode). After testing, when the curved surface 651 of the permanent magnet 6 arc surface 65 is a circular arc surface, the noise radiation at the motor breathing mode can be reduced by 5dBA relative to the traditional solution. If the circular arc surface is changed to an elliptical arc surface or a quadratic curve surface, the noise radiation at the motor breathing mode can be reduced by 6dBA relative to the traditional solution. If the rotor core is segmented by further adopting a segmented skew pole solution, the noise radiation at the motor breathing mode can be further reduced by 2dBA on the basis of the above.

[0121] In summary, the motor rotor 400 of the above embodiment can effectively reduce the electromagnetic noise of the motor, thereby reducing the noise generated by the electric vehicle during operation and improving the riding comfort of the passengers.

[0122] Obviously, those skilled in the art may make various changes and modifications to this application without departing from the spirit and scope of this application. Thus, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalents, this application is intended to include these modifications and variations.

Claims

1. A motor rotor, characterized in that: It includes a rotor core and a magnetic assembly, wherein the magnetic assembly is embedded in the rotor core and located between the inner wall and the outer wall of the rotor core; The magnetic assembly includes n magnetic unit pairs spaced apart along the circumference of the rotor core, where n is an integer greater than or equal to 2, each magnetic unit pair includes two magnetic units, each magnetic unit includes at least one permanent magnet and a permanent magnet slot corresponding to the at least one permanent magnet, the permanent magnet slot is provided in the rotor core, and each permanent magnet is provided in a corresponding permanent magnet slot; Each of the permanent magnets has a first surface and a second surface arranged opposite to each other along its magnetization direction. In at least some of the magnetic units, the first surface and / or the second surface of at least one of the permanent magnets is configured as a trimmed surface, and the trimmed surface has at least one curved surface, and a protrusion is formed at the position of the at least one curved surface.

2. The motor rotor according to claim 1, characterized in that The ratio of the thickness of each protrusion on the arc-trimming surface to the minimum thickness of the permanent magnet where it is located is less than or equal to 0.5, and the minimum thickness of the permanent magnet is the minimum distance between the first surface and the second surface along its magnetization direction.

3. The motor rotor according to claim 2, characterized in that: The projection of each arc-shaped surface of the arc-trimming surface on the first plane is: a circular arc line, an elliptical arc line or a quadratic curve; The first plane is perpendicular to the axis of the rotor core.

4. The motor rotor according to claim 1, wherein: The arc-trimming surface has an arc-shaped surface, both ends of which along the bending direction are respectively connected to the two side surfaces of the permanent magnet where the arc-shaped surface is located, and the protrusion formed at the position of the arc-shaped surface is an arc-shaped protrusion.

5. The motor rotor according to any one of claims 1 to 4, characterized in that: The at least one permanent magnet of the magnetic unit includes two first permanent magnets, and the two first permanent magnets are symmetrically arranged in a V shape along the center line of the magnetic unit; The first surface and / or the second surface of the first permanent magnet is configured as the arc-trimming surface.

6. The motor rotor according to claim 5, characterized in that: The relationship between the thickness of each protrusion in the arc-trimmed surface of the first permanent magnet and the corresponding minimum thickness of the first permanent magnet satisfies: 0.1H11≤H12≤0.4H11, wherein H12 is the thickness of the protrusion, and H11 is the corresponding minimum thickness of the first permanent magnet.

7. The motor rotor according to claim 5, characterized in that: The magnetic unit having the first permanent magnet further includes two second permanent magnets, the two second permanent magnets being symmetrically arranged in a V shape along the center line of the corresponding magnetic unit, and along the center line of the magnetic unit, the second permanent magnet is arranged on the side of the first permanent magnet facing the inner wall surface of the rotor core; The first surface and / or the second surface of the second permanent magnet is configured as the arc-trimming surface.

8. The motor rotor according to claim 7, characterized in that: The relationship between the thickness of each protrusion in the arc-trimmed surface of the second permanent magnet and the corresponding minimum thickness of the second permanent magnet satisfies: H22≤0.1H21, wherein H22 is the thickness of the protrusion, and H21 is the corresponding minimum thickness of the second permanent magnet.

9. The motor rotor according to any one of claims 1 to 4, characterized in that: Each of the permanent magnet slots has a first slot wall surface and a second slot wall surface spaced apart along the magnetization direction of the corresponding permanent magnet, the gap between the first slot wall surface and the first surface of the permanent magnet being less than 0.1 mm, and the gap between the second slot wall surface and the second surface of the permanent magnet being less than 0.1 mm.

10. The motor rotor according to any one of claims 1 to 4, characterized in that: At least a portion of the outer wall surface of the rotor core is configured as an arc-trimmed wall surface, wherein the arc-trimmed wall surface has at least one arc-shaped surface, and a convexity or a concaveity is formed at the position of the at least one arc-shaped surface.

11. The motor rotor according to any one of claims 1 to 4, characterized in that: The rotor core comprises a plurality of rotor core segments sequentially arranged along the axis of the rotor core, and each of the rotor core segments is embedded with one of the magnetic components; The magnetic components on at least two of the rotor core segments are staggered along the circumferential direction of the rotor core.

12. A motor, characterized in that: The invention comprises a motor stator and a motor rotor according to any one of claims 1 to 11, wherein the motor stator and the motor rotor are coaxially sleeved.

13. A powertrain, characterized in that: It comprises a gearbox, a transmission shaft and the motor as claimed in claim 12, wherein the gearbox is in driving connection with the motor rotor of the motor through the transmission shaft.

14. An electric vehicle, characterized in that: The vehicle comprises a vehicle body, wheels, and the power assembly as claimed in claim 13, wherein the power assembly is arranged on the vehicle body and is used to drive the wheels.

Images