Double-layer permanent magnet radial field modulation magnetic gear and hub motor for new energy vehicles

Abstract

A dual-layer permanent magnet radial field modulation magnetic gear and its application in a hub motor for new energy vehicles are disclosed. The magnetic gear comprises a high-speed rotor, a magnetizing stator, and a low-speed rotor. The high-speed rotor consists of a high-speed rotor yoke and high-speed rotor permanent magnets. The low-speed rotor consists of an inner layer of low-speed rotor permanent magnets, an outer layer of low-speed rotor permanent magnets, and a low-speed rotor yoke. The high-speed rotor yoke, high-speed rotor permanent magnets, magnetizing stator, inner layer of low-speed rotor permanent magnets, outer layer of low-speed rotor permanent magnets, and low-speed rotor yoke are coaxially nested from the inside out. The high-speed rotor permanent magnets are composed of multiple umbrella-tooth structured permanent magnet modules. The inner layer of low-speed rotor permanent magnets is magnetized using a Halbach arrangement, the outer layer of low-speed rotor permanent magnets is radially magnetized, and the high-speed rotor permanent magnets are magnetized using an umbrella-tooth Halbach arrangement. This invention can improve the torque transmission capability of the magnetic gear, suppress magnetic saturation, enhance the magnetic field modulation effect, and increase the torque density of the magnetic gear.

Description

Technical Field

[0001] This invention relates to the field of new energy vehicle technology, and in particular to a double-layer permanent magnet radial field modulation magnetic gear and a hub motor for new energy vehicles. Background Technology

[0002] Currently, the automotive industry is accelerating its transformation towards intelligent and electric vehicles, with new energy vehicles becoming a core carrier for promoting carbon neutrality in the transportation sector. As a typical representative of distributed drive systems, direct-drive in-wheel motors, with their advantages of eliminating the transmission chain and high integration, can be directly embedded inside the wheel, eliminating intermediate components such as traditional gearboxes and drive shafts. This significantly improves the overall space utilization and transmission efficiency of the vehicle, making it a key development direction for future high-performance electric vehicle power systems. However, the space constraints and high performance requirements of in-wheel motors present a sharp contradiction. On the one hand, the limited space inside the wheel requires the motor to achieve low-speed, high-torque output within a limited volume to meet the demands of complex operating conditions such as vehicle start-up, hill climbing, and frequent acceleration and deceleration. On the other hand, when vehicles travel on bumpy or unpaved roads, stringent requirements are placed on the operational smoothness of the drive system (such as low torque pulsation and low vibration noise). Traditional in-wheel motors, limited by electromagnetic design and structural topology, often face problems such as insufficient torque density, high magnetic field harmonic content, and poor transmission smoothness. Magnetic gears, a novel transmission device based on the principle of magnetic field modulation, achieve bidirectional modulation of high-speed and low-speed magnetic fields by introducing a non-magnetic gap into the tuning magnet. Ultimately, electromechanical energy conversion is achieved through harmonic magnetic field coupling. Compared to traditional mechanical gears, their contactless transmission characteristics avoid friction and wear, require no lubrication or maintenance, and offer advantages such as low noise and compact structure, demonstrating significant application potential in the field of magnetically modulated hub motors for new energy vehicles.

[0003] In the existing technology, the integrated design of magnetic gears and hub motors still faces the following bottlenecks: First, traditional hub motors mostly adopt a single-layer permanent magnet structure, and the peak value of the air gap magnetic flux density is limited by the material properties and spatial arrangement of the permanent magnets, making it difficult to further improve the torque density. Second, the pole pair matching design of existing magnetic gears is not optimized enough, and the pole pair relationship between the magnetizing stator and the permanent magnets of the inner and outer rotors does not form an efficient coupling, resulting in insufficient magnetic field modulation efficiency, high non-working harmonic content, and consequently, reduced rotor operation stability. Third, the high-speed rotor and low-speed rotor of the hub motor need to simultaneously meet the output requirements of high speed and low speed. The magnetic field distribution characteristics of traditional single-layer permanent magnets are difficult to balance the dual goals of high-speed magnetic field modulation and low-speed high torque output, limiting the improvement of the overall performance of the hub motor.

[0004] Therefore, developing a hub motor magnetic gear that balances high torque density, low harmonic distortion, and smooth operation is a technical problem that needs to be solved by those skilled in the art. Summary of the Invention

[0005] The purpose of this invention is to provide a double-layer permanent magnet radial field modulation magnetic gear and a hub motor for new energy vehicles, so as to improve the torque transmission capability of the magnetic gear, suppress magnetic saturation, enhance the magnetic field modulation effect, and increase the torque density of the magnetic gear.

[0006] One aspect of the present invention provides a double-layer permanent magnet radial field modulation magnetic gear, including a high-speed rotor, a magnetizing stator and a low-speed rotor. The high-speed rotor is composed of a high-speed rotor yoke and a high-speed rotor permanent magnet, and the low-speed rotor is composed of a low-speed rotor inner layer permanent magnet, a low-speed rotor outer layer permanent magnet and a low-speed rotor yoke.

[0007] The high-speed rotor yoke, high-speed rotor permanent magnet, magnetic adjustment stator, low-speed rotor inner permanent magnet, low-speed rotor outer permanent magnet, and low-speed rotor yoke are coaxially nested from the inside to the outside.

[0008] The high-speed rotor permanent magnet is composed of multiple umbrella-shaped tooth structure permanent magnet modules. The inner permanent magnet of the low-speed rotor is magnetized in a Halbach arrangement, the outer permanent magnet of the low-speed rotor is radially magnetized, and the permanent magnet of the high-speed rotor is magnetized in a Halbach arrangement with umbrella-shaped teeth.

[0009] A first radial air gap is provided between the high-speed rotor permanent magnet and the magnet-adjusting stator, and a second radial air gap is provided between the magnet-adjusting stator and the inner permanent magnet of the low-speed rotor. The magnetic fields of the high-speed rotor permanent magnet, the inner permanent magnet of the low-speed rotor, and the outer permanent magnet of the low-speed rotor are radially modulated by the magnet-adjusting stator.

[0010] The high-speed rotor permanent magnet, the low-speed rotor inner permanent magnet, the low-speed rotor outer permanent magnet and the magnetizing stator constitute a dual-sum modulation, and the magnetic flux is guided through a dual radial magnetic circuit;

[0011] The high-speed rotor permanent magnet, the low-speed rotor inner layer permanent magnet, and the magnetically modulating stator constitute the first coaxial magnetic gear structure for radial and modulated operation.

[0012] The high-speed rotor permanent magnet, the low-speed rotor outer permanent magnet, and the magnetizing stator constitute a radial and modulated second coaxial magnetic gear structure;

[0013] The high-speed rotor, acting as the input rotor, is modulated by the magnetizing stator, which drives the low-speed rotor to rotate.

[0014] Another aspect of the present invention provides a hub motor for a new energy vehicle, the hub motor including the aforementioned magnetic gear.

[0015] The double-layer permanent magnet radial field modulation magnetic gear and new energy vehicle hub motor provided by the present invention have the following beneficial effects:

[0016] (1) Through the optimization of the double-layer permanent magnet structure and magnetization method, the air gap magnetic flux density of the present invention is significantly improved compared with the traditional single-layer permanent magnet, and the torque density is also improved compared with similar magnetic gears;

[0017] (2) The magnetic gear of the present invention has two rotors, namely a high-speed rotor and a low-speed rotor. The high-speed rotor is used as input and the low-speed rotor is driven to rotate by the modulation effect of the magnetic stator. This can achieve the effect of low speed and high torque, and also take into account the high-speed magnetic field modulation, which helps to improve the overall performance of the hub motor.

[0018] (3) In the magnetic gear of the present invention, the high-speed rotor permanent magnet is magnetized by the Halbach arrangement of umbrella teeth. The Halbach magnetization of umbrella teeth significantly improves the air gap magnetic field strength, torque density, running stability and power density of the magnetic gear by optimizing the magnetic field distribution, while reducing tooth cogging torque fluctuation and radial force pulsation.

[0019] (4) In the magnetic gear of the present invention, the two rotor motion units and the rotation unit are independent of each other, the motion mode is simple, the end leakage magnetic effect is small, the dynamic response is fast, and electromagnetic design and optimization can be carried out separately.

[0020] (5) The high-speed rotor permanent magnet, the low-speed rotor inner permanent magnet, the low-speed rotor outer permanent magnet and the magnetizing stator constitute a double-sum modulation. The magnetic flux is guided by the double radial magnetic circuit, which can reduce the influence of magnetic saturation effect without reducing the total flux generated by the permanent magnet, and effectively suppress the magnetic saturation effect.

[0021] (6) The present invention can effectively improve the magnetic field modulation effect and enhance the torque density of the magnetic gear without changing the amount of permanent magnets in the high-speed rotor and the low-speed rotor. Attached Figure Description

[0022] Figure 1 This is a three-dimensional topological structure diagram of the double-layer permanent magnet radial field modulation magnetic gear in an embodiment of the present invention;

[0023] Figure 2 This is a three-dimensional oblique view of the double-layer permanent magnet radial field modulation magnetic gear in an embodiment of the present invention;

[0024] Figure 3 This is a front view of the double-layer permanent magnet radial field modulation magnetic gear in an embodiment of the present invention.

[0025] Figure 4 This is a quarter-section view of the double-layer permanent magnet radial field modulation magnetic gear in an embodiment of the present invention.

[0026] Figure 5 This is a schematic diagram of the structure of the inner permanent magnet and the outer permanent magnet of the low-speed rotor.

[0027] Figure 6 This is a schematic diagram of the high-speed rotor.

[0028] Figure 7 This is a schematic diagram of the low-speed rotor.

[0029] Figure 8 This is a side sectional view of the double-layer permanent magnet radial field modulation magnetic gear in an embodiment of the present invention.

[0030] Figure 9 This is a front sectional view of the double-layer permanent magnet radial field modulation magnetic gear in an embodiment of the present invention.

[0031] Figure 10 This is a comparison diagram of the radial inner air gap magnetic induction intensity of the magnetic gear of the present invention and the conventional radial magnetic gear;

[0032] Figure 11 This is a comparison diagram of the radial external air gap magnetic induction intensity of the magnetic gear of the present invention and the conventional radial magnetic gear. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] Please see Figures 1 to 9 The dual-layer permanent magnet radial field modulation magnetic gear provided in this embodiment of the invention includes a high-speed rotor, a magnetically modulating stator 3, and a low-speed rotor.

[0035] The high-speed rotor consists of a high-speed rotor yoke 1 and a high-speed rotor permanent magnet 2, while the low-speed rotor consists of a low-speed rotor inner permanent magnet 4, a low-speed rotor outer permanent magnet 5, and a low-speed rotor yoke 6.

[0036] The high-speed rotor yoke 1, high-speed rotor permanent magnet 2, magnetic adjustment stator 3, low-speed rotor inner permanent magnet 4, low-speed rotor outer permanent magnet 5, and low-speed rotor yoke 6 are coaxially nested from the inside to the outside.

[0037] In this embodiment, the high-speed rotor permanent magnet 2 is composed of 24 umbrella-shaped toothed permanent magnet modules 201, each 50mm in length. The permanent magnet modules 201 are made of neodymium iron boron magnets, which enhance magnetic field strength and stability.

[0038] Specifically, the permanent magnet module 201 includes a first permanent magnet 21 and two second permanent magnets 22. The first permanent magnet 21 and the two second permanent magnets 22 form an umbrella-shaped tooth structure, and the volume of the first permanent magnet 21 is larger than the volume of the second permanent magnet 22.

[0039] Please refer to this carefully. Figure 6 The arrows in the figure indicate the magnetization direction. The high-speed rotor permanent magnet 2 is magnetized using a Halbach arrangement of umbrella-shaped teeth.

[0040] The first permanent magnet 21 is magnetized in the reverse radial direction, and the second permanent magnet 22 is magnetized in the oblique reverse radial direction. The tilt angle of the second permanent magnet 22 is 45°. The magnetization directions of two adjacent first permanent magnets 21 are opposite.

[0041] The low-speed rotor adopts a double-layer permanent magnet structure design; please refer to this document for details. Figure 7 The arrows in the figure indicate the magnetization direction. The inner permanent magnets 4 of the low-speed rotor are magnetized using the Halbach arrangement, while the outer permanent magnets 5 of the low-speed rotor are magnetized radially.

[0042] Because the high-speed rotor permanent magnet 2 is magnetized using an umbrella-shaped Halbach arrangement, and the low-speed rotor inner permanent magnet 4 is magnetized using a Halbach arrangement, the segmented deflection of the permanent magnets (such as alternating N and S offsets) can enhance the magnetic field strength in local areas and suppress the reverse magnetic field, thus optimizing the air gap magnetic flux density distribution. Furthermore, because the low-speed rotor outer permanent magnet 5 is radially magnetized, the magnetic field direction is ensured to be radially distributed, simplifying the magnetic field modulation path.

[0043] A first radial air gap 7 is provided between the high-speed rotor permanent magnet 2 and the magnetic adjustment stator 3, and a second radial air gap 8 is provided between the magnetic adjustment stator 3 and the low-speed rotor inner permanent magnet 4. The magnetic field of the high-speed rotor permanent magnet 2, the low-speed rotor inner permanent magnet 4 and the low-speed rotor outer permanent magnet 5 are radially modulated by the magnetic adjustment stator 3.

[0044] The high-speed rotor permanent magnet 2, the low-speed rotor inner permanent magnet 4, the low-speed rotor outer permanent magnet 5, and the adjusting stator 3 constitute a dual-sum modulation. The magnetic flux is guided through a dual radial magnetic circuit. Specifically, the high-speed rotor permanent magnet 2, the low-speed rotor inner permanent magnet 4, and the adjusting stator 3 form a first coaxial magnetic gear structure for radial modulation; the high-speed rotor permanent magnet 2, the low-speed rotor outer permanent magnet 5, and the adjusting stator 3 form a second coaxial magnetic gear structure for radial modulation. The high-speed rotor, acting as the input rotor, drives the low-speed rotor to rotate through the modulation effect of the adjusting stator 3, achieving high torque at low speed.

[0045] Please refer to this carefully. Figure 4In this embodiment, the magnetic stator 3 is composed of 23 magnetic cores 9, formed by a magnetic material lamination process. The interval between two adjacent magnetic cores 9 is 7.83°, and the axial length of the magnetic core 9 is 50mm. The magnetic stator 3 has radial modulation performance, which can modulate the radial permanent magnet magnetic field.

[0046] The number of inner permanent magnets 4 in the low-speed rotor is 76, and the angle of the inner permanent magnets 4 is 4.74°. The number of outer permanent magnets 5 in the low-speed rotor is 38, and the angle of the outer permanent magnets 5 is 9.47°. The axial length of both the inner permanent magnets 4 and the outer permanent magnets 5 in the low-speed rotor is 50mm.

[0047] In this embodiment, both the high-speed rotor yoke 1 and the low-speed rotor yoke 6 are made of ferrite.

[0048] In this embodiment, the number of adjusting magnet cores in the adjusting stator 3 The number of pole pairs of the permanent magnet on the high-speed rotor permanent magnet 2 The number of pole pairs of the permanent magnets on the inner layer of the low-speed rotor 4 The number of pole pairs of the permanent magnets on the outer permanent magnet 5 of the low-speed rotor They respectively satisfy the following conditions:

[0049] = ;

[0050] = .

[0051] Through the above expressions, the high-speed rotor permanent magnet 2, the low-speed rotor inner permanent magnet 4 and the magnetic adjustment stator 3 constitute the first coaxial magnetic gear structure for radial and modulated operation, and the high-speed rotor permanent magnet 2, the low-speed rotor outer permanent magnet 5 and the magnetic adjustment stator 3 constitute the second coaxial magnetic gear structure for radial and modulated operation.

[0052] also, That is, the number of permanent magnet pole pairs of the inner permanent magnet 4 and the outer permanent magnet 5 of the low-speed rotor must be equal to satisfy the modulation principle.

[0053] In this embodiment, the gear transmission ratio of the magnetic gear is... Satisfy the following formula:

[0054] ;

[0055] in, This is the high-speed rotor speed. This refers to the low-speed rotor speed.

[0056] The above expression shows that the rotational speed of the magnetic gear is equal to the ratio of the number of pole pairs of the permanent magnets on the rotor.

[0057] A comparative analysis of the magnetic gear of this invention with that of a conventional radial magnetic gear reveals that... Figure 10 It can be seen that the magnetic field strength in the air gap of the magnetic gear of the present invention is significantly higher than that of the traditional radial field modulated magnetic gear, and the magnetic field modulation effect of the magnetic gear of the present invention is significantly enhanced. From Figure 11 It can be seen that, compared with the traditional radial magnetic gear, the magnetic field strength in the outer air gap of the magnetic gear of the present invention is significantly improved, which is beneficial to improving the output torque density of the magnetic gear.

[0058] An embodiment of the present invention also provides a hub motor for a new energy vehicle, which includes the aforementioned magnetic gear.

[0059] In summary, the double-layer permanent magnet radial field modulation magnetic gear and new energy vehicle hub motor provided by the present invention have the following beneficial effects:

[0060] (1) Through the optimization of the double-layer permanent magnet structure and magnetization method, the air gap magnetic flux density of the present invention is significantly improved compared with the traditional single-layer permanent magnet, and the torque density is also improved compared with similar magnetic gears;

[0061] (2) The magnetic gear of the present invention has two rotors, namely a high-speed rotor and a low-speed rotor. The high-speed rotor is used as input and the low-speed rotor is driven to rotate by the modulation effect of the magnetic stator. This can achieve the effect of low speed and high torque, and also take into account the high-speed magnetic field modulation, which helps to improve the overall performance of the hub motor.

[0062] (3) In the magnetic gear of the present invention, the high-speed rotor permanent magnet is magnetized by the Halbach arrangement of umbrella teeth. The Halbach magnetization of umbrella teeth significantly improves the air gap magnetic field strength, torque density, running stability and power density of the magnetic gear by optimizing the magnetic field distribution, while reducing tooth cogging torque fluctuation and radial force pulsation.

[0063] (4) In the magnetic gear of the present invention, the two rotor motion units and the rotation unit are independent of each other, the motion mode is simple, the end leakage magnetic effect is small, the dynamic response is fast, and electromagnetic design and optimization can be carried out separately.

[0064] (5) The high-speed rotor permanent magnet, the low-speed rotor inner permanent magnet, the low-speed rotor outer permanent magnet and the magnetizing stator constitute a double-sum modulation. The magnetic flux is guided by the double radial magnetic circuit, which can reduce the influence of magnetic saturation effect without reducing the total flux generated by the permanent magnet, and effectively suppress the magnetic saturation effect.

[0065] (6) The present invention can effectively improve the magnetic field modulation effect and enhance the torque density of the magnetic gear without changing the amount of permanent magnets in the high-speed rotor and the low-speed rotor.

[0066] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0067] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A double-layer permanent magnet radial field modulation type magnetic gear, characterized in that, It includes a high-speed rotor, a magnetically adjustable stator, and a low-speed rotor. The high-speed rotor consists of a high-speed rotor yoke and a high-speed rotor permanent magnet. The low-speed rotor consists of a low-speed rotor inner permanent magnet, a low-speed rotor outer permanent magnet, and a low-speed rotor yoke. The high-speed rotor yoke, high-speed rotor permanent magnet, magnetic adjustment stator, low-speed rotor inner permanent magnet, low-speed rotor outer permanent magnet, and low-speed rotor yoke are coaxially nested from the inside to the outside. The high-speed rotor permanent magnet is composed of multiple umbrella-shaped tooth structure permanent magnet modules. The inner permanent magnet of the low-speed rotor is magnetized in a Halbach arrangement, the outer permanent magnet of the low-speed rotor is radially magnetized, and the permanent magnet of the high-speed rotor is magnetized in a Halbach arrangement of umbrella-shaped teeth. A first radial air gap is provided between the high-speed rotor permanent magnet and the magnet-adjusting stator, and a second radial air gap is provided between the magnet-adjusting stator and the inner permanent magnet of the low-speed rotor. The magnetic fields of the high-speed rotor permanent magnet, the inner permanent magnet of the low-speed rotor, and the outer permanent magnet of the low-speed rotor are radially modulated by the magnet-adjusting stator. The high-speed rotor permanent magnet, the low-speed rotor inner permanent magnet, the low-speed rotor outer permanent magnet and the magnetizing stator constitute a dual-sum modulation, and the magnetic flux is guided through a dual radial magnetic circuit; The high-speed rotor permanent magnet, the low-speed rotor inner layer permanent magnet, and the magnetically modulating stator constitute the first coaxial magnetic gear structure for radial and modulated operation. The high-speed rotor permanent magnet, the low-speed rotor outer permanent magnet, and the magnetizing stator constitute a radial and modulated second coaxial magnetic gear structure; The high-speed rotor, as the input rotor, drives the low-speed rotor to rotate through the modulation effect of the magnetizing stator. The permanent magnet module includes a first permanent magnet and two second permanent magnets. The first permanent magnet and the two second permanent magnets form an umbrella-shaped tooth structure. The volume of the first permanent magnet is larger than the volume of the second permanent magnets.

2. The double-layer permanent magnet radial field modulation magnetic gear according to claim 1, characterized in that, The first permanent magnet is magnetized in the reverse radial direction, and the second permanent magnet is magnetized in the oblique reverse radial direction. The tilt angle of the second permanent magnet is 45°.

3. The double-layer permanent magnet radial field modulation magnetic gear according to claim 1, characterized in that, The magnetic stator is composed of multiple magnetic cores, which are formed by stacking magnetic materials. The spacing between two adjacent magnetic cores is 7.83°, and the axial length of the magnetic core is 50mm.

4. The double-layer permanent magnet radial field modulation magnetic gear according to claim 1, characterized in that, Number of magnet cores in the magnetizing stator The number of pole pairs of permanent magnets on the high-speed rotor permanent magnet The number of pole pairs of permanent magnets on the inner layer of the low-speed rotor The number of pole pairs of permanent magnets on the outer permanent magnet of the low-speed rotor They respectively satisfy the following conditions: = 。 5. The double-layer permanent magnet radial field modulation magnetic gear according to claim 4, characterized in that, The gear ratio of the magnetic gear Satisfy the following formula: ； in, This is the high-speed rotor speed. This is the low-speed rotor speed.

6. The double-layer permanent magnet radial field modulation magnetic gear according to claim 1, characterized in that, The angle of the inner permanent magnet of the low-speed rotor is 4.74°, the angle of the outer permanent magnet of the low-speed rotor is 9.47°, and the axial length of both the inner and outer permanent magnets of the low-speed rotor is 50mm.

7. The double-layer permanent magnet radial field modulation magnetic gear according to claim 1, characterized in that, The high-speed rotor permanent magnet is made of neodymium iron boron magnet.

8. The double-layer permanent magnet radial field modulation magnetic gear according to claim 1, characterized in that, Both the high-speed rotor yoke and the low-speed rotor yoke are made of ferrite.

9. A hub motor for a new energy vehicle, characterized in that, Including the double-layer permanent magnet radial field modulated magnetic gear as described in any one of claims 1 to 8.

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