Magnetic gear and motor

Abstract

The application relates to the field of electric machines, in particular to a magnetic gear and an electric machine. The magnetic gear comprises an outer rotor provided with an axial through hole, and an outer permanent magnet is arranged in the circumferential direction of the outer rotor; an inner rotor is coaxially arranged in the through hole and is spaced apart from the outer rotor, an inner permanent magnet and a damping part are arranged on the inner rotor, the damping part is conductive and non-magnetic, and is located between the inner permanent magnet and the outer edge of the inner rotor; and a magnetism adjusting ring is coaxially arranged in the space and is spaced apart from the outer rotor and the inner rotor to form an air gap, so that the torque fluctuation during rotation of the magnetic gear is reduced, and the time required for reaching a stable rotating speed during rotation is shortened.

Description

Technical Field

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

[0002] Traditional mechanical gear drives are direct-contact transmissions, which can lead to problems such as tooth breakage, wear, friction, and lubrication issues during operation. This results in high maintenance costs, and the noise and lubricant leaks can cause serious pollution. Modern magnetic gear drives, on the other hand, eliminate physical contact between the driving and driven gears, utilizing the force between permanent magnets for transmission. Therefore, permanent magnet gear transmissions are an ideal choice for the transmission field, offering advantages such as high performance and reliability.

[0003] However, existing magnetic gears generally suffer from large torque fluctuations or insufficient torque capacity, and the use of excessive permanent magnets, resulting in low operating performance.

[0004] There is currently no good solution to the above-mentioned technical problems. Summary of the Invention

[0005] To reduce torque fluctuations during the rotation of magnetic gears and shorten the time required for them to reach a stable speed, a magnetic gear and motor are proposed.

[0006] On the one hand, this invention proposes a magnetic gear, comprising:

[0007] The outer rotor has an axial through hole, and an outer permanent magnet is arranged circumferentially on the outer rotor;

[0008] An inner rotor is coaxially disposed within the through hole and spaced apart from the outer rotor. An inner permanent magnet and a damping part are disposed on the inner rotor. The damping part is electrically conductive but not magnetically conductive and is located between the inner permanent magnet and the outer edge of the inner rotor.

[0009] The adjusting magnetic ring is coaxially disposed within the interval with the outer rotor and forms an air gap between the outer rotor and the inner rotor.

[0010] Preferably, a plurality of axially penetrating mounting holes are uniformly arranged along the circumference of the inner rotor, and the plurality of mounting holes are located on the outside of the inner permanent magnet; metal strips are arranged in the mounting holes, and the same end of the plurality of metal strips is electrically connected sequentially along the circumference of the inner rotor.

[0011] Preferably, an expansion joint is provided between the mounting hole and the outer circular surface of the inner rotor, and the metal strip is inserted into the mounting hole.

[0012] Preferably, the plurality of metal strips located outside the single inner permanent magnet constitute a damping unit, and a groove is provided between two adjacent damping units, the groove extending through both ends of the inner rotor.

[0013] Preferably, the groove has a flared structure, the bottom of the groove has a width of L1 in the circumferential direction of the inner rotor, the inner permanent magnet is rectangular, the width of the inner permanent magnet extends along the radial direction of the rotor, and the width of the inner permanent magnet is L2.

[0014] Preferably, the bottom surface of the groove is a first plane, which is symmetrical about a diameter of the inner rotor, and the distance between the first plane and the center of the inner rotor is S1; the inner permanent magnet includes a second plane close to the center of the inner rotor, which is symmetrical about a diameter of the inner rotor, and the distance between the second plane and the center of the inner rotor is S2, and the radius of the inner rotor is R, then S2 < S1 < R; preferably, S2 < S1 < S2 + L2 < R.

[0015] Preferably, the adjusting ring includes a plurality of adjusting blocks connected in sequence by connecting ribs and a non-magnetic filler between two adjacent adjusting blocks.

[0016] Preferably, the adjusting block is stepped, comprising an outer adjusting section near the outer rotor and an inner adjusting section near the inner rotor, wherein the tangential width of the inner adjusting section is greater than the tangential width of the outer adjusting section; the radial thickness of the outer adjusting section along the adjusting ring is h1, and the total radial thickness of the adjusting block along the adjusting ring is h.

[0017] Preferably, the connecting rib has a radial thickness of h2 along the magnetic adjustment ring.

[0018] Preferably, the magnetization direction of both the inner permanent magnet and the outer permanent magnet is radial; and / or, the outer permanent magnet is disposed on the inner circular surface of the outer rotor.

[0019] On the other hand, the present invention also proposes an electric motor, including the magnetic wheel, wherein a coil is wound on the inner rotor or the outer rotor.

[0020] This invention provides a damping section on the inner rotor. When the rotational speed of the inner rotor relative to the outer rotor is not within a reasonable range, the magnetic fields generated by the inner and outer permanent magnets no longer change synchronously. The damping section generates an induced current, which in turn generates an induced magnetic field. The induced magnetic field generated by the damping section hinders the synchronization between the magnetic fields of the inner and outer permanent magnets. In other words, the induced magnetic field generated by the damping section helps to synchronize the magnetic fields generated by the inner and outer permanent magnets, thereby reducing the speed and torque fluctuations of the inner rotor, outer rotor, or adjusting ring. During acceleration or deceleration, it helps to shorten the time to reach a stable speed. Attached Figure Description

[0021] Figure 1 This is a schematic diagram showing the relationship between the outer rotor, inner rotor, and adjusting ring in an embodiment of the present invention;

[0022] Figure 2 This is a schematic diagram illustrating the relationship between the outer rotor and the inner rotor in an embodiment of the present invention;

[0023] Figure 3 This is a schematic diagram of the axial direction of the outer rotor in an embodiment of the present invention;

[0024] Figure 4 This is a schematic diagram of the axial direction of the adjusting magnetic ring according to an embodiment of the present invention;

[0025] Figure 5 This is an embodiment of the present invention. Figure 4 Enlarged view of point A in the middle;

[0026] Figure 6 This is a schematic diagram of the axial direction of the inner rotor when a metal strip is provided in an embodiment of the present invention;

[0027] Figure 7 This is a schematic diagram of the rotor's axial direction in an embodiment of the present invention;

[0028] Figure 8 This is an embodiment of the present invention. Figure 7 Enlarged view at point B in the middle;

[0029] Figure 9 This is a comparison table of the output torque of the present invention and existing technologies.

[0030] The reference numerals in the attached figures are as follows:

[0031] 1. Outer rotor; 101. Through hole; 2. Inner rotor; 201. Inner permanent magnet; 2011. Second plane; 202. Mounting hole; 203. Expansion joint; 204. Groove; 2041. First plane; 3. Adjusting ring; 301. Adjusting block; 302. Connecting rib; 303. Filler; 304. Fixing hole; 3011. Outer adjusting part; 3012. Inner adjusting part; 4. Outer permanent magnet; 5. Metal strip. Detailed Implementation

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] This invention relates to the field of electric motors, specifically to a magnetic gear and an electric motor.

[0037] Traditional mechanical gear drives are direct-contact transmissions, which can lead to problems such as tooth breakage, wear, friction, and lubrication issues during operation. This results in high maintenance costs, and the noise and lubricant leaks can cause serious pollution. Modern magnetic gear drives, on the other hand, eliminate physical contact between the driving and driven gears, utilizing the force between permanent magnets for transmission. Therefore, permanent magnet gear transmissions are an ideal choice for the transmission field, offering advantages such as high performance and reliability.

[0038] However, existing magnetic gears generally suffer from large torque fluctuations or insufficient torque capacity, and the use of excessive permanent magnets, resulting in low operating performance.

[0039] To address the aforementioned technical problems, a magnetic gear and motor are proposed, which are described below in conjunction with the appendix. Figure 1-9 This invention is described.

[0040] The magnetic gear proposed in this invention, such as Figure 1-8 As shown, it includes: an outer rotor 1 with an axial through hole 101, and an outer permanent magnet 4 arranged circumferentially on the outer rotor 1; an inner rotor 2, which is coaxially arranged with the outer rotor 1 in the through hole 101 and forms a gap with the outer rotor 1, and is provided with an inner permanent magnet 201 and a damping part, the damping part being electrically conductive but not magnetically conductive and located between the inner permanent magnet 201 and the outer edge of the inner rotor 2; and a magnetic adjusting ring 3, which is coaxially arranged with the outer rotor 1 in the gap and forms an air gap with the outer rotor 1 and the inner rotor 2.

[0041] The inner permanent magnet 201 and the outer permanent magnet 4 interact through the adjusting ring 3. When the rotational speed of the inner rotor 2 relative to the outer rotor 1 is not within a reasonable range, the magnetic field generated by the inner permanent magnet 201 and the magnetic field generated by the outer permanent magnet 4 are no longer synchronized. The damping part generates an induced current, which in turn generates an induced magnetic field. The induced magnetic field generated by the damping part hinders the synchronization between the magnetic field of the inner permanent magnet 201 and the magnetic field of the outer permanent magnet 4. That is, the induced magnetic field generated by the damping part helps to synchronize the magnetic field generated by the inner permanent magnet 201 and the outer permanent magnet 4, thereby reducing the speed and torque fluctuation of the inner rotor 2, the outer rotor 1 or the adjusting ring 3. During acceleration or deceleration, it helps to shorten the time to accelerate or decelerate to a stable speed.

[0042] The damping section increases the torque and improves the utilization rate of the permanent magnet. Compared with the prior art, fewer inner permanent magnets 201 and outer permanent magnets 4 are required to achieve the same output torque, thereby reducing the amount of permanent magnets used and improving the running performance of the magnetic gear.

[0043] Preferred, such as Figure 6-7 As shown, multiple axially penetrating mounting holes 202 are uniformly arranged along the circumference of the inner rotor 2, and the multiple mounting holes 202 are located on the outside of the inner permanent magnet 201; metal strips 5 are arranged in the mounting holes 202, and the same end of the multiple metal strips 5 are electrically connected sequentially along the circumference of the inner rotor 2.

[0044] In the claims and description, "multiple" refers to "at least two". Multiple metal strips 5 cut magnetic field lines to generate induced current, which in turn generates an induced magnetic field. Because the induced current flows simultaneously within the multiple metal strips 5 of the inner rotor 2, the electromagnetic force between the inner rotor 2 and the outer rotor 1 is evenly distributed circumferentially, which helps improve the stability of the output torque of the magnetic gear. The metal strips 5 can be copper or aluminum strips. The metal strips 5 can be formed by casting. Since the inner rotor 2 is formed by stacking silicon steel sheets, casting allows the molten metal to fully contact the silicon steel sheets, especially at the edges between adjacent silicon steel sheets; this improves the connection strength between the metal strips 5 and the inner rotor 2, which is beneficial for the smooth rotation of the inner rotor 2.

[0045] Preferred, such as Figure 7 As shown, an expansion joint 203 is provided between the mounting hole 202 and the outer circular surface of the inner rotor 2, and the metal strip 5 is inserted into the mounting hole 202.

[0046] The expansion joint 203 can deform on both sides. The metal strip 5 is inserted into the mounting hole 202 with an interference fit, making the expansion joint 203 larger. The mounting hole 202 compresses the metal strip 5, which not only reduces the wear on the surface of the metal strip 5 due to the interference fit, thus ensuring that the resistance of the metal strip 5 does not increase due to wear, but also increases the tightness of the fit between the metal strip 5 and the mounting hole 202, which is beneficial to the stable rotation of the inner rotor 2. The sides of the expansion joint 203 are connected to the outer circular surface of the inner rotor 2 by a rounded transition, which effectively reduces internal stress and improves the structural strength of the inner rotor 2.

[0047] Preferred, such as Figure 6-8 As shown, multiple metal strips 5 located outside a single inner permanent magnet 201 form a damping unit, and a groove 204 is provided between two adjacent damping units, the groove 204 penetrating both ends of the inner rotor 2 along the axial direction.

[0048] The grooves 204 can increase the magnetic flux density of the magnetic field generated by the inner permanent magnet 201 between two adjacent grooves 204, which is beneficial to increasing the magnetomotive force and reducing torque ripple. The number of damping units is the same as the number of inner permanent magnets 201, and the number of grooves 204 is the same as the number of inner permanent magnets 201.

[0049] Preferred, such as Figure 7-8 As shown, the groove 204 has a flared structure, and the bottom of the groove 204 has a width of L1 in the circumferential direction of the inner rotor 2. The inner permanent magnet 201 is rectangular, and its width extends along the radial direction of the rotor, with a width of L2.

[0050] At that time, the magnetic flux density between two adjacent grooves 204 is insufficient, resulting in a smaller output torque; At that time, although the magnetic flux density was high, the torque fluctuation was large due to the large distance between the two adjacent internal permanent magnets 201; by making It ensures magnetic flux density while reducing torque ripple.

[0051] Preferred, such as Figure 7 As shown, the bottom surface of the groove 204 is a first plane 2041, which is symmetrical about one diameter of the inner rotor 2. The distance between the first plane 2041 and the center of the inner rotor 2 is S1. The inner permanent magnet 201 includes a second plane 2011 near the center of the inner rotor 2. The second plane 2011 is symmetrical about one diameter of the inner rotor 2. The distance between the second plane 2011 and the center of the inner rotor 2 is S2. The radius of the inner rotor 2 is R. Then, S2 < S1 < R; preferably, S2 < S1 < S2 + L2 < R.

[0052] By limiting the depth of the groove by making S2 < S1 < R, and further by making S2 < S1 < S2 + L2 < R, the generation of harmonics can be effectively reduced when the inner rotor 2 rotates relative to the outer rotor 1, thereby reducing harmonic losses. Preferably, the cross-sectional shape of the groove 204 is an isosceles trapezoid, with the larger end of the isosceles trapezoid facing the outer edge of the inner rotor 2. The symmetry of the isosceles trapezoid coincides with the symmetry line of the two adjacent inner permanent magnets 201, that is, the magnetic flux density generated by the inner permanent magnets 201 on both sides of the circumference of the groove 204 is the same, which is beneficial to improving the stability of torque output.

[0053] Preferred, such as Figure 4-5 As shown, the magnetic adjustment ring 3 includes multiple magnetic adjustment blocks 301 connected in sequence by connecting ribs 302, and a non-magnetic filler 303 between two adjacent magnetic adjustment blocks 301.

[0054] The magnetic field induced by the adjusting block 301 plays a regulating role between the outer rotor 1 and the inner rotor 2, matching the magnetic field generated by the inner permanent magnet 201 with that generated by the outer permanent magnet 4. Filling the space between two adjacent adjusting blocks 301 with a non-magnetic filler 303 can improve the mechanical structural strength of the adjusting ring 3. Since the filler 303 is a non-magnetic material, it can further increase the magnetic field density within the adjusting block 301. When the adjusting ring 3 is used as a rotor, it has a large output torque. When the adjusting ring 3 is made of multilayer silicon steel sheets, an annular retaining ring is set at each of the axial ends of the adjusting ring 3. The inner diameter of the annular retaining ring is the same as the inner diameter of the adjusting ring, and the outer diameter of the annular retaining ring is the same as the outer diameter of the adjusting ring. The annular retaining ring is provided with a fixing hole 304, which is aligned with the spacing between the two adjacent adjusting blocks. Bolts are inserted into the fixing holes 304 to clamp the silicon steel sheets at both ends of the axial direction of the adjusting ring 3.

[0055] Preferred, such as Figure 5As shown, the adjusting block 301 is stepped, and includes an outer adjusting part 3011 near the outer rotor 1 and an inner adjusting part 3012 near the inner rotor 2. The tangential width of the inner adjusting part 3012 is greater than the tangential width of the outer adjusting part 3011. The radial thickness of the outer adjusting part 3011 along the adjusting ring 3 is h1, and the total radial thickness of the adjusting block 301 along the adjusting ring 3 is h.

[0056] The adjusting magnetic block 301 is wider near the inner rotor 2, which can concentrate the magnetic field lines of the inner permanent magnet 201, increase the magnetic flux density, and increase the air gap magnetic flux density between the adjusting magnetic ring 3 and the inner rotor 2 and outer rotor 1, thereby improving the output torque and increasing efficiency. The stepped shape of the adjusting magnetic block 301 not only makes the adjusting magnetic block 301 wider near the inner rotor 2, but also reduces the manufacturing difficulty; simulation tests have shown that... This allows the magnetic flux density of the inner permanent magnet 201 to reach the optimal range, which is beneficial for improving the output torque of the adjusting ring 3 and enhancing the performance of the magnetic gear. Preferably, the adjusting block 301 has two stepped layers, with the radial thickness of the inner step being (h-h1-h2).

[0057] Preferred, such as Figure 5 As shown, the connecting rib 302 has a radial thickness of h2 along the magnetic adjusting ring 3.

[0058] make While ensuring the structural strength of the connecting rib 302, it is also beneficial to ensure the air gap magnetic flux density between the adjusting magnetic ring 3 and the inner rotor 2 and the outer rotor 1, thereby ensuring the output torque of the adjusting magnetic ring 3.

[0059] Preferred, such as Figure 3 As shown, the magnetization direction of the inner permanent magnet 201 and the outer permanent magnet 4 is both radial; and / or, the outer permanent magnet 4 is disposed on the inner circular surface of the outer rotor 1.

[0060] The magnetization directions of two adjacent inner permanent magnets 201 are opposite, and the magnetization directions of two adjacent outer permanent magnets 4 are also opposite. The radial magnetization generates a longer magnetic field line, which can improve the interaction force between the inner permanent magnets 201 and the outer permanent magnets 4, thereby improving the stability of the output force of the inner rotor 2 or the outer rotor 1. The outer permanent magnets 4 are located on the inner circular surface of the outer rotor 1, which can reduce the distance between the outer permanent magnets 4 and the inner permanent magnets 201 and improve the output torque.

[0061] The present invention also proposes an electric motor, including the aforementioned magnetic wheel, with a coil wound on the inner rotor 2 or the outer rotor 1.

[0062] like Figure 9As shown, this motor can achieve low-speed, high-torque mechanical output. The motor with the aforementioned magnetic gear can be designed for two operating conditions: first, the outer rotor 1 is fixed, and the inner rotor 2 and the adjusting ring 3 rotate in the same direction, with the inner rotor 2 rotating at high speed and the adjusting ring 3 rotating at low speed; second, the adjusting ring 3 is fixed, and the inner rotor 2 and outer rotor 1 rotate in opposite directions, with the inner rotor 2 rotating at high speed and the outer rotor 1 rotating at low speed. The design is tailored to different requirements. The low-speed, high-torque motor is a combination of a synchronous motor and magnetic gears. The magnetic field generated by the outer permanent magnet 4 should change synchronously with the magnetic field generated by the inner permanent magnet 201 when transmitted to the inner rotor 2. When the aforementioned interacting magnetic fields change synchronously, the damping part does not generate induced current and does not function. When the load is too large, the inner rotor 2 or the adjusting ring 3 may slip, causing the aforementioned interacting magnetic fields to change asynchronously. At this time, the damping part generates induced current and induced magnetic field, functioning to ensure the synchronous change of the aforementioned interacting magnetic fields and to ensure the stability of the speed of the inner rotor 2 or the adjusting ring 3, reducing torque fluctuations.

[0063] 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: The outer rotor (1) is provided with an axial through hole (101), and an outer permanent magnet (4) is provided in the circumference of the outer rotor (1). The inner rotor (2) is coaxially disposed in the through hole (101) with the outer rotor (1) and is spaced apart from the outer rotor (1). The inner rotor (2) is provided with an inner permanent magnet (201) and a damping part. The damping part is electrically conductive but not magnetic and is located between the inner permanent magnet (201) and the outer edge of the inner rotor (2). The adjusting magnetic ring (3) is coaxially arranged with the outer rotor (1) in the interval and forms an air gap with the outer rotor (1) and the inner rotor (2); A plurality of mounting holes (202) are uniformly arranged along the circumference of the inner rotor (2) and penetrate the inner rotor (2) axially. The plurality of mounting holes (202) are located on the outside of the inner permanent magnet (201). A metal strip (5) is arranged in the mounting hole (202), and the same end of the plurality of metal strips (5) is electrically connected sequentially along the circumference of the inner rotor (2). The multiple metal strips (5) located outside the single inner permanent magnet (201) form a damping unit, and a groove (204) is provided between two adjacent damping units. The groove (204) penetrates both ends of the inner rotor (2) axially. The groove (204) has a flared structure, and the bottom of the groove (204) has a width of L1 in the circumferential direction of the inner rotor (2). The inner permanent magnet (201) is rectangular, and the width direction of the inner permanent magnet (201) extends along the radial direction of the rotor. The width of the inner permanent magnet (201) is L2, 0.3≤ ≤0.

6.

2. The magnetic gear according to claim 1, characterized in that, An expansion joint (203) is provided between the mounting hole (202) and the outer circular surface of the inner rotor (2), and the metal strip (5) is inserted into the mounting hole (202).

3. The magnetic gear according to claim 1, characterized in that, The bottom surface of the groove (204) is a first plane, which is symmetrical about a diameter of the inner rotor. The distance between the first plane and the center of the inner rotor (2) is S1. The inner permanent magnet (201) includes a second plane close to the center of the inner rotor. The second plane is symmetrical about a diameter of the inner rotor. The distance between the second plane and the center of the inner rotor (2) is S2. The radius of the inner rotor (2) is R. Then, S2 < S1 < R.

4. The magnetic gear according to claim 3, characterized in that, S2 < S1 < S2 + L2 < R.

5. The magnetic gear according to claim 1, characterized in that, The magnetic ring (3) includes a plurality of magnetic blocks (301) connected in sequence by connecting ribs (302), and a non-magnetic filler (303) between two adjacent magnetic blocks (301).

6. The magnetic gear according to claim 5, characterized in that, The adjusting block (301) is stepped, and includes an outer adjusting part (3011) near the outer rotor (1) and an inner adjusting part (3012) near the inner rotor (2). The tangential width of the inner adjusting part (3012) is greater than the tangential width of the outer adjusting part (3011). The radial thickness of the outer adjusting part (3011) along the adjusting ring (3) is h1, and the total radial thickness of the adjusting block (301) along the adjusting ring (3) is h, 0.5≤ ≤0.

8.

7. The magnetic gear according to claim 6, characterized in that, The connecting rib (302) has a radial thickness of h2 along the magnetic adjusting ring (3), 0.1≤ ≤0.

2.

8. The magnetic gear according to any one of claims 1-7, characterized in that, The magnetization direction of the inner permanent magnet (201) and the outer permanent magnet (4) is radial; and / or, the outer permanent magnet (4) is disposed on the inner circular surface of the outer rotor (1).

9. An electric motor, characterized in that, The magnetic gear includes any one of claims 1-8, wherein a coil is wound on the inner rotor (2) or the outer rotor (1).

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