Magnetic gear and compound motor

Abstract

This invention relates to the field of electric motors, specifically to a magnetic gear and a composite motor. The magnetic gear includes an inner rotor, a magnetic adjusting ring, and an outer rotor coaxially arranged from the inside out. The outer rotor is provided with multiple outer permanent magnets, and the inner rotor is provided with multiple inner permanent magnets. The multiple inner permanent magnets are uniformly distributed along the circumference of the inner rotor and magnetized along the tangential direction of the inner rotor. Each inner permanent magnet includes a first outer end facing the outer edge of the inner rotor and a first inner end facing the center of the inner rotor. The projection of the inner permanent magnet in the axial direction of the inner rotor is stepped, and the tangential width of the first outer end is greater than the tangential width of the first inner end. This reduces torque fluctuations during magnetic gear rotation and shortens the time required to reach a stable rotational speed.

Description

Technical Field

[0001] This invention relates to the field of electric motors, specifically to a magnetic gear and a composite motor. Background Technology

[0002] Magnetic field modulated gears enable contactless transmission, with all permanent magnets participating in torque transmission. They offer advantages such as high torque density, low vibration and noise, no need for lubrication or maintenance, and automatic overload protection, and have been widely studied in recent years. Magnetic gear composite motors combine magnetic field modulated gears with a composite motor in a compact design. They feature two rotors, one for high speed and one for low speed, with reused rotor structures. This allows for direct torque transmission and amplification, resulting in high torque density.

[0003] Existing magnetic gear composite motors generally suffer from large torque fluctuations or insufficient torque capacity, significant harmonic losses, low utilization of permanent magnets, and low motor torque and power density.

[0004] An existing vernier magnetic gear composite motor has a high-speed rotor with a double-layer permanent magnet structure. This results in a large amount of permanent magnets, a complex manufacturing process, low utilization of permanent magnets, and high cost.

[0005] There is currently no good solution to the above-mentioned technical problems. Summary of the Invention

[0006] To reduce torque fluctuations during magnetic gear rotation and the long time required for rotation to reach a stable speed, a magnetic gear and a composite motor are proposed.

[0007] On one hand, the present invention provides a magnetic gear, comprising: an inner rotor, a magnetic adjusting ring, and an outer rotor arranged coaxially from the inside to the outside; the outer rotor is provided with a plurality of outer permanent magnets;

[0008] The inner rotor is provided with a plurality of inner permanent magnets, which are evenly distributed along the circumference of the inner rotor and magnetized along the tangential direction of the inner rotor.

[0009] The inner permanent magnet includes a first outer end facing the outer edge of the inner rotor and a first inner end facing the center of the inner rotor; the projection of the inner permanent magnet in the axial direction of the inner rotor is stepped and the tangential width of the first outer end is greater than the tangential width of the first inner end.

[0010] Preferably, the internal permanent magnet includes a first-order internal magnet, a second-order internal magnet, and a third-order internal magnet extending from the first outer end to the first inner end;

[0011] The tangential width of the first-order inner magnet is L1, the tangential width of the second-order inner magnet is L2, and the tangential width of the third-order inner magnet is L3.

[0012] Preferably, the radial length of the inner permanent magnet along the inner rotor is L, and the radial length of the first layer along the inner rotor is L4.

[0013] Preferably, the first-order internal magnet, the second-order internal magnet, and the third-order internal magnet are a single integral magnet;

[0014] Alternatively, the first-order internal magnet, the second-order internal magnet, and the third-order internal magnet may each be a separate magnet.

[0015] Preferably, the external permanent magnet includes a second outer end facing the outer edge of the external rotor and a second inner end facing the axis of the external rotor. The projection of the external permanent magnet in the axial direction of the external rotor is stepped, and the tangential width of the second inner end is greater than the tangential width of the second outer end. The external permanent magnet is magnetized along the tangential direction of the external rotor.

[0016] Preferably, the external permanent magnet includes a first-order external magnet and a second-order external magnet extending from the second inner end to the second outer end;

[0017] The tangential width of the first-order external magnet is H1, and the tangential width of the second-order external magnet is H2.

[0018] Preferably, the magnetic adjustment ring includes a plurality of circumferentially evenly distributed magnetic adjustment blocks, with an injection molding interval between two adjacent magnetic adjustment blocks. The magnetic adjustment blocks are trapezoidal and the extension lines of their two waist sides intersect the axis of the magnetic adjustment ring.

[0019] The included angle between the two waist sides of the magnetic adjustment block is α, and the included angle between the two sides of the injection molding interval is β, then 0.8β≤α≤1.5β.

[0020] Preferably, two adjacent magnetic adjustment blocks are connected by a connecting strip, the connecting strip being located at one end near the center of the magnetic adjustment ring, and the injection molding interval is filled with non-magnetic material.

[0021] On the other hand, the present invention also provides a composite motor, including a coil winding and the magnetic gear, wherein the coil winding is disposed on the inner rotor or the outer rotor.

[0022] Preferably, a plurality of magnetic slots are uniformly arranged circumferentially along the inner surface of the outer rotor, and a plurality of winding slots are arranged circumferentially along the outer side of the plurality of magnetic slots. The outer permanent magnet is disposed in the magnetic slots, and the coil winding is disposed in the winding slots.

[0023] By adjusting the size of the two ends of the inner permanent magnet, the magnetic field lines of the permanent magnet near the air gap travel a short magnetic path, which mainly contributes to the peak value of the air gap magnetic flux density; while the magnetic field lines of the permanent magnet far from the air gap travel a long magnetic path, which, in addition to contributing to the peak value of the air gap magnetic flux density, also determines the size of the two sides of the peak value. Designing the inner permanent magnet in a stepped shape is beneficial for processing and assembly, improving production efficiency; on the other hand, it can also further improve the sinusoidal nature of the air gap magnetic flux density and reduce harmonic losses. Attached Figure Description

[0024] Figure 1 This is a schematic diagram showing the relationship between the inner rotor, the adjusting ring, and the outer rotor in an embodiment of the present invention;

[0025] Figure 2 This is a schematic diagram of the axial direction of the outer rotor in an embodiment of the present invention;

[0026] Figure 3 This is a schematic diagram of the axial direction of the adjusting magnetic ring according to an embodiment of the present invention;

[0027] Figure 4 This is a schematic diagram of the rotor's axial direction in an embodiment of the present invention;

[0028] Figure 5 This is a schematic diagram of the permanent magnet structure in an embodiment of the present invention;

[0029] Figure 6 This is a schematic diagram of the external permanent magnet structure in an embodiment of the present invention;

[0030] Figure 7 Logarithmic diagram of air gap magnetic flux density harmonics in existing technology;

[0031] Figure 8 This is a logarithmic diagram of the air gap magnetic flux density harmonics in an embodiment of the present invention.

[0032] The reference numerals in the attached figures are as follows:

[0033] 1. Inner rotor; 2. Outer rotor; 3. Adjusting ring; 301. Adjusting block; 302. Connecting strip; 4. Inner permanent magnet; 401. First-order inner magnet; 402. Second-order inner magnet; 403. Third-order inner magnet; 5. Outer permanent magnet; 501. First-order outer magnet; 502. Second-order outer magnet; 6. Injection molding gap; 7. Coil winding. Detailed Implementation

[0034] 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.

[0035] The terminology used in the embodiments of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms “a,” “the,” and “the” used in the embodiments of this invention and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise. “Multiple” generally includes at least two, but does not exclude the inclusion of at least one.

[0036] It should be understood that the term "and / or" used in this document is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Furthermore, the character " / " in this document generally indicates that the related objects are in an "or" relationship; "first" and "second" are used only to distinguish different technical features, not to indicate a chronological order; and "upper," "lower," "before," and "after" are used only to more conveniently illustrate the positional relationship of technical features and only have meaning when combined with actual usage or the specific location descriptions in the preceding text, and are not absolute positional relationships.

[0037] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a product or system comprising a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a product or system. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the product or system that includes said element.

[0038] This invention relates to the field of electric motors, specifically to a magnetic gear and a composite motor.

[0039] Magnetic field modulated gears enable contactless transmission, with all permanent magnets participating in torque transmission. They offer advantages such as high torque density, low vibration and noise, no need for lubrication or maintenance, and automatic overload protection, and have been widely studied in recent years. Magnetic gear composite motors combine magnetic field modulated gears with a composite motor in a compact design. They feature two rotors, one for high speed and one for low speed, with reused rotor structures. This allows for direct torque transmission and amplification, resulting in high torque density.

[0040] Existing magnetic gear composite motors generally suffer from large torque fluctuations or insufficient torque capacity, significant harmonic losses, low utilization of permanent magnets, and low motor torque and power density.

[0041] An existing vernier magnetic gear composite motor has a high-speed rotor with a double-layer permanent magnet structure. This results in a large amount of permanent magnets, a complex manufacturing process, low utilization of permanent magnets, and high cost.

[0042] In response to the above technical problems, such as Figure 1-8 As shown, the present invention provides a magnetic gear comprising: an inner rotor 1, a magnetic adjusting ring 3, and an outer rotor 2 arranged coaxially from the inside to the outside; the outer rotor 2 is provided with a plurality of outer permanent magnets 5; the inner rotor 1 is provided with a plurality of inner permanent magnets 4, the plurality of inner permanent magnets 4 being uniformly distributed along the circumference of the inner rotor 1, and the plurality of inner permanent magnets 4 being magnetized along the tangential direction of the inner rotor 1; the inner permanent magnet 4 includes a first outer end facing the outer edge of the inner rotor 1 and a first inner end facing the center of the inner rotor 1; the projection of the inner permanent magnet in the axial direction of the inner rotor is stepped, and the tangential width of the first outer end is greater than the tangential width of the first inner end.

[0043] The magnetization directions of two adjacent inner permanent magnets are opposite. By setting the size of the two ends of the inner permanent magnet 4, the magnetic field lines of the permanent magnet near the air gap travel a short magnetic path, which mainly contributes to the peak value of the air gap magnetic flux density; the magnetic field lines of the permanent magnet far from the air gap travel a long magnetic path, which, in addition to contributing to the peak value of the air gap magnetic flux density, also determines the size on both sides of the peak value. Designing the inner permanent magnet 4 as a stepped shape is beneficial for processing and assembly, improving production efficiency; on the other hand, it can also further improve the sinusoidal nature of the air gap magnetic flux density, increase torque, and reduce harmonic losses, such as... Figure 7 and Figure 8 As shown, increasing the torque also means improving the utilization rate of permanent magnets. Compared with existing technologies, fewer permanent magnets are needed to output the same amount of torque, thus reducing the amount of permanent magnets used and lowering costs.

[0044] Preferred, such as Figure 4 and Figure 5 As shown, the inner permanent magnet 4 includes a first-order inner magnet 401, a second-order inner magnet 402, and a third-order inner magnet 403 extending from the first outer end to the first inner end; the tangential width of the first-order inner magnet 401 is L1, the tangential width of the second-order inner magnet 402 is L2, and the tangential width of the third-order inner magnet 403 is L3.

[0045] pass This makes the air gap magnetic flux density between the inner rotor 1 and the adjusting ring 3 closer to a sine wave, reducing harmonic losses.

[0046] Preferably, the radial length of the inner permanent magnet 4 is L, and the radial length of the first layer is L4.

[0047] exist On this basis, further through This makes the air gap magnetic flux density between the inner rotor 1 and the adjusting ring 3 closer to a sine wave, reducing harmonic losses.

[0048] Preferably, the first-order internal magnet 401, the second-order internal magnet 402, and the third-order internal magnet 403 are the same integral magnet;

[0049] Alternatively, the first-order internal magnet 401, the second-order internal magnet 402, and the third-order internal magnet 403 may each be a separate magnet.

[0050] When the first-order internal magnet 401, the second-order internal magnet 402, and the third-order internal magnet 403 are the same integral magnet, their structure is simple and easy to assemble; when the first-order internal magnet 401, the second-order internal magnet 402, and the third-order internal magnet 403 are individual magnets, the eddy current loss of the magnet itself can be effectively reduced, and energy consumption can be reduced.

[0051] Preferred, such as Figure 6 As shown, the external permanent magnet 5 includes a first-order external magnet 501 and a second-order external magnet 502 extending from the second inner end to the second outer end;

[0052] The tangential width of the first-order external magnet 501 is H1, and the tangential width of the second-order external magnet 502 is H2.

[0053] The magnetic field lines of permanent magnets near the air gap travel a short magnetic path, primarily contributing to the peak value of the air gap magnetic flux density; the magnetic field lines of permanent magnets farther from the air gap travel a long magnetic path, contributing not only to the peak value of the air gap magnetic flux density but also determining the magnitude of the peak value on both sides. This can further make the air gap magnetic flux density between the outer rotor 2 and the adjusting magnetic ring 3 present a shape that is larger in the middle and smaller on both sides, closer to a sine wave, and further enhance the air gap magnetic flux density between the outer rotor 2 and the adjusting magnetic ring 3, thereby improving the torque output capability of the adjusting magnetic ring 3.

[0054] Preferred, such as Figure 2 and Figure 6 As shown, the external permanent magnet 5 includes a second outer end facing the outer edge of the external rotor 2 and a second inner end facing the axis of the external rotor 2. In the axial direction of the external rotor 2, the external permanent magnet 5 is stepped in the axial projection of the external rotor 2 and is tangentially magnetized in the external rotor 2. The tangential width of the second inner end is greater than the tangential width of the second outer end.

[0055] Compared to radial magnetization along the inner rotor 1 and outer rotor 2, circumferential magnetization along the outer rotor 2 by the inner permanent magnet 4 and outer permanent magnet 5 has a better magnetic focusing effect. It can reduce the magnetic field path length between the inner permanent magnet 4 and the outer permanent magnet 5, and at the same time, it can improve the sinusoidal nature of the air gap magnetic flux density between the adjusting ring 3 and the inner rotor 1 and outer rotor 2, reduce harmonic losses, and thus improve the transmission efficiency of the magnetic gear.

[0056] The outer permanent magnet 5 is designed in a stepped shape, interacting with the inner permanent magnet 4. This further enhances the air gap density between the adjusting ring 3 and the outer rotor 2, increases the magnetomotive force, improves the torque output capability of the adjusting ring 3, and enhances the torque amplification capability. By making both the inner permanent magnet 4 and the outer permanent magnet 5 stepped, and by making the tangential width at one end closer to the adjusting ring 3 greater than the tangential width at the other end, the air gap magnetic flux density can be made to have a shape that is larger in the middle and smaller at both ends, which is closer to a sine wave, thereby reducing harmonic losses. The magnetization directions of two adjacent outer permanent magnets 5 are opposite.

[0057] Preferred, such as Figure 3 As shown, the magnetic ring 3 includes multiple circumferentially evenly distributed magnetic blocks 301, with an injection molding interval 6 formed between two adjacent magnetic blocks 301. The magnetic blocks 301 are trapezoidal and the extension lines of their two waist sides intersect the axis of the magnetic ring 3.

[0058] The included angle between the two waist sides of the adjusting magnetic block 301 is α, and the included angle between the two sides of the injection molding interval 6 is β. Then 0.8β≤α≤1.5β.

[0059] By using 0.8β≤α≤1.5β, the magnetic fields generated by the inner permanent magnet 4 and the outer permanent magnet 5 can interact more sinusoidally at the magnetic adjustment ring 3, thereby increasing the magnetic flux density in the magnetic adjustment block 301 and thus increasing the output torque of the magnetic adjustment ring 3.

[0060] The number of pole pairs of the outer permanent magnet 5 is Ps, the number of adjusting magnetic blocks 301 is Pm, and the number of pole pairs of the inner permanent magnet 4 is Pi. Then Pi + Ps = Pm, forming a magnetic gear effect. When the outer rotor 2 is fixed, the rotational speed of the inner rotor 1 is Ni, and the rotational speed of the adjusting magnetic ring 3 is Nm. Ni / Nm = Pm / Pi.

[0061] Preferred, such as Figure 3 As shown, two adjacent magnetic adjustment blocks 301 are connected by a connecting strip 302. The connecting strip 302 is located at one end near the center of the magnetic adjustment ring 3, and the injection molding interval 6 is filled with non-magnetic material.

[0062] Epoxy resin can be selected as the non-magnetic material. By setting the connecting strip 302 on the side close to the center of the magnetic ring 3 and filling the injection gap 6 with epoxy resin, the mechanical strength of the magnetic ring 3 is effectively improved, the assembly difficulty is reduced, and the torque output of the magnetic ring 3 is ensured to be stable.

[0063] The present invention also provides a composite motor, including a coil winding 7 and a magnetic gear, wherein the coil winding 7 is disposed on an inner rotor 1 or an outer rotor 2.

[0064] This composite motor is a permanent magnet motor with a magnetic gear load. The coil winding 7 is mounted on the inner rotor 1, which serves as the motor's stator. The outer rotor 2 is also mounted on the outer rotor 1, which serves as the motor's stator. One of the inner rotor 1 and the adjusting ring 3 serves as a mechanical output component; the adjusting ring 3 acts as the output unit. When the coil winding 7 is mounted on the outer rotor 2, the number of electromagnetic pole pairs generated by the coil winding 7 is the same as the number of pole pairs of the inner permanent magnet 4. The electromagnetic torque generated by the energized coil winding 7 drives the inner rotor 1 to rotate. Under the action of the adjusting ring 3, the adjusting ring 3 rotates at a low speed in the same direction as the inner rotor 1. The torque is transmitted to the adjusting ring 3, resulting in a torque amplification effect. The rotation of the adjusting ring 3 can act as an output unit, performing work externally, thus significantly improving the overall torque density of the composite motor and reducing energy consumption.

[0065] This composite motor is a low-speed, high-torque motor, mainly used in low-speed, high-torque applications. The sinusoidal nature of the air gap magnetic flux density is improved, harmonic losses are reduced, and energy consumption is decreased; the output efficiency of the composite motor is also improved. Specifically, the magnetic field lines of the permanent magnets near the air gap (including the air gap between the inner rotor 1 and the adjusting ring 3, and the air gap between the outer rotor 2 and the adjusting ring 3) have shorter magnetic paths, primarily contributing to the peak value of the air gap magnetic flux density; the magnetic field lines of the permanent magnets farther from the air gap have longer magnetic paths, contributing not only to the peak value of the air gap magnetic flux density but also determining the size of the two sides of the peak value, making the air gap magnetic flux density exhibit a shape that is larger in the middle and smaller at the two sides, closer to a sine wave.

[0066] When the outer rotor 2 is fixed as the stator, the coil winding 7 is set on the outer rotor 2. At this time, the output part has two working conditions: one is that the magnetic ring 3 is the output part, which outputs a large torque; the other is that both the inner rotor 1 and the magnetic ring 3 are output parts, which simultaneously output torque to do work. At this time, the composite motor is a dual mechanical port motor.

[0067] Preferred, such as Figure 2 As shown, multiple magnetic slots are uniformly arranged circumferentially along the inner surface of the outer rotor 2, and multiple winding slots are arranged circumferentially along the outer side of the multiple magnetic slots. The outer permanent magnet 5 is arranged in the magnetic slots, and the coil winding 7 is arranged in the winding slots.

[0068] By placing the permanent magnet in the magnetic groove on the inner surface of the outer rotor 2, closer to the inner rotor 1, the magnetic circuit is shortened, which helps to improve the magnetic field interaction between the inner rotor 1 and the outer rotor 2, and improves the output torque of the inner rotor 1.

[0069] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention. The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the protection scope of the present invention.

Claims

1. A magnetic gear, characterized in that, include: An inner rotor (1), a magnetic adjusting ring (3), and an outer rotor (2) are arranged coaxially from the inside to the outside; the outer rotor (2) is provided with multiple outer permanent magnets (5); The inner rotor (1) is provided with a plurality of inner permanent magnets (4), which are evenly distributed along the circumference of the inner rotor (1) and magnetized along the tangential direction of the inner rotor (1). The inner permanent magnet (4) includes a first outer end facing the outer edge of the inner rotor (1) and a first inner end facing the center of the inner rotor (1); the projection of the inner permanent magnet (4) in the axial direction of the inner rotor (1) is stepped and the tangential width of the first outer end is greater than the tangential width of the first inner end. The external permanent magnet (5) includes a second outer end facing the outer edge of the external rotor (2) and a second inner end facing the axis of the external rotor (2). The projection of the external permanent magnet (5) in the axial direction of the external rotor (2) is stepped and the tangential width of the second inner end is greater than the tangential width of the second outer end. The external permanent magnet (5) is magnetized along the tangential direction of the external rotor (22). The inner permanent magnet (4) includes a first-order inner magnet (401), a second-order inner magnet (402) and a third-order inner magnet (403) extending from the first outer end to the first inner end. The tangential width of the first-order inner magnet (401) is L1, the tangential width of the second-order inner magnet (402) is L2, and the tangential width of the third-order inner magnet (403) is L3, then 0.6 ≤ ≤0.8, 0.4≤ ≤0.6; The external permanent magnet (5) includes a first-order external magnet (501) and a second-order external magnet (502) extending from the second inner end to the second outer end. The tangential width of the first-order external magnet (501) is H1, and the tangential width of the second-order external magnet (502) is H2, then 0.4 ≤ ≤0.

9.

2. The magnetic gear according to claim 1, characterized in that, The radial length of the inner permanent magnet (4) along the inner rotor (1) is L, and the radial length of the first-order magnet along the inner rotor (1) is L4. ≤L4≤ .

3. The magnetic gear according to claim 2, characterized in that, The first-order internal magnet (401), the second-order internal magnet (402), and the third-order internal magnet (403) are the same integral magnet; Alternatively, the first-order internal magnet (401), the second-order internal magnet (402), and the third-order internal magnet (403) may each be a separate magnet.

4. The magnetic gear according to any one of claims 1-3, characterized in that, The magnetic ring (3) includes multiple circumferentially evenly distributed magnetic blocks (301), and an injection molding interval (6) is formed between two adjacent magnetic blocks (301). The magnetic blocks (301) are trapezoidal and the extension lines of their two waist sides intersect the axis of the magnetic ring (3). The included angle between the two sides of the magnetic adjustment block (301) is α, and the included angle between the two sides of the injection molding interval (6) is β, then 0.8β≤α≤1.5β.

5. The magnetic gear according to claim 4, characterized in that, The two adjacent magnetic adjustment blocks (301) are connected by a connecting strip (302), the connecting strip (302) is located at one end near the center of the magnetic adjustment ring (3), and the injection molding interval (6) is filled with non-magnetic material.

6. A composite motor, characterized in that, It includes a coil winding (7) and a magnetic gear as described in any one of claims 1-5, wherein the coil winding (7) is disposed on the inner rotor (1) or the outer rotor (2).

7. The composite motor according to claim 6, characterized in that, Multiple magnetic slots are uniformly arranged along the circumference of the inner surface of the outer rotor (2), and multiple winding slots are arranged along the circumference of the outer rotor (2) on the outer side of the multiple magnetic slots. The outer permanent magnet (5) is arranged in the magnetic slots, and the coil winding (7) is arranged in the winding slots.

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