A geometrically tilted three-dimensional halbach magnetic ring assembly and a standardized preparation method thereof

Abstract

The application relates to a geometrically inclined three-dimensional Halbach magnetic ring assembly and a standardized preparation method thereof. The magnetic ring assembly comprises a plurality of magnetic sectors arranged in a ring structure in sequence along a circumferential direction. The inner surface of each magnetic sector is an inclined surface, and the normal line of the inclined surface and the radial direction form an angle of 30 DEG. After assembly, the inner surfaces are aligned and spliced to form a smooth annular inner hole wall, and the outer surfaces form an annular outer wall with an angle step. The magnetization direction of each magnetic sector is the Halbach array magnetization direction in a two-dimensional plane, and the angle between the magnetization direction and the normal direction of the inner surface is 30 DEG. During preparation, a standard unidirectional magnetization field is used in cooperation with a 30 DEG inclined fixer for magnetization. After magnetization is completed, the fixer is removed, and the sectors are rotated by 30 DEG for assembly. The application replaces the complex three-dimensional magnetization technology by geometrically inclined design, ensures the radial magnetic aggregation effect, obtains the Z-axis magnetic field component, and realizes the standardized production of the three-dimensional Halbach magnetic ring.

Description

Technical Field

[0001] This invention belongs to the field of permanent magnet component design and high-precision magnetic field application, specifically a geometrically tilted three-dimensional Halbach magnetic ring component and its standardized preparation method. Background Technology

[0002] Halbach magnetic ring arrays, with their unique magnetic field distribution characteristics of "single-sided magnetic concentration and single-sided self-shielding," are widely used in permanent magnet drives, precision sensing, magnetic detection, and magnetic resonance imaging. Traditional Halbach magnetic rings are mostly two-dimensional planar structures, and their magnetic field uniformity can only be guaranteed in the radial plane (xoy plane), which can meet the magnetic field requirements of planar devices.

[0003] With the increasing demand for three-dimensional magnetic field space in scientific research and industrial applications, it is necessary to extend the two-dimensional Halbach magnetic ring along the axial direction (Z-axis direction) to form a three-dimensional structure. In the prior art, the main approaches to realizing the three-dimensional Halbach magnetic ring include: (1) using a complex multi-dimensional magnetization system to magnetize the magnet in three dimensions, so that the magnetization direction of each magnet segment has both radial and axial components. For example, existing patent documents disclose a three-dimensional Halbach magnet for magnetic resonance, which adopts a superposition scheme of two-dimensional Halbach magnet combination and two-sided three-dimensional Halbach magnet combination, including oblique magnets with magnetic axial components. In addition, the prior art also proposes to realize three-dimensional magnetization by deviating the magnetization direction of at least two ring magnet elements from the ring plane, so that the component perpendicular to the ring plane changes with the azimuth cosine. (2) adding additional magnet combinations at both ends of the two-dimensional Halbach magnetic ring for magnetic field compensation. For example, the prior art increases the compensation of the magnetic field in the target area by adding shimming rings at both ends of the magnet.

[0004] However, the above-mentioned existing technical solutions have obvious technical defects. Solution (1) requires a complex multi-dimensional magnetization coil and a precise magnetic field control system, which results in high equipment costs (approximately 5-8 times that of standard unidirectional magnetization equipment) and complex magnetization processes (the magnetization time for a single piece is approximately 3-5 times that of the standard unidirectional magnetization process), making it difficult to achieve standardized mass production. Although Solution (2) improves the axial magnetic field uniformity to some extent, it increases the axial length and overall weight of the magnet assembly, and the magnetization direction of the compensating magnets at both ends needs to be precisely matched with the main magnet, making assembly difficult.

[0005] Therefore, there is an urgent need for a technical solution that can realize the Z-axis magnetic field component of a three-dimensional Halbach magnetic ring and can be standardized and prepared using a standard two-dimensional magnetization process. Summary of the Invention

[0006] This application aims to address the technical shortcomings of existing three-dimensional Halbach magnetic rings, which require complex three-dimensional magnetization systems, have high equipment costs, and are difficult to standardize in production. It provides a magnetic ring component that achieves the effect of a three-dimensional Halbach magnetic ring through geometric tilting design and its standardized preparation method.

[0007] This application adopts the following technical solution: A geometrically tilted three-dimensional Halbach magnetic ring assembly includes multiple magnetic sectors arranged sequentially along the circumference to form a ring structure. Each magnetic sector has an inner surface and an outer surface. The inner surface is an inclined surface, and its normal forms a 30° angle with the radial direction of the magnetic sector. After the multiple magnetic sectors are assembled, the inner surfaces are aligned and spliced ​​to form a smooth annular inner wall, and the outer surfaces form an annular outer wall with angular steps. The axis of the annular inner wall coincides with the axis of the magnetic ring assembly. The magnetization direction of each magnetic sector is the Halbach array magnetization direction in a two-dimensional plane, located in the radial plane of the magnetic sector, and has a 30° angle with the normal direction of the inner surface.

[0008] Preferably, in one specific embodiment, the angle between the inner surface of the magnet sector and the bottom surface of the magnet sector is 30°. The magnet sector is rotated 30° around its tangential axis in the assembled state. The tangential axis is perpendicular to the radial and axial directions of the magnet sector. After rotation, the normals of each inner surface point to the central axis of the annular structure, so that each inner surface is spliced ​​to form the smooth annular inner hole wall.

[0009] In one embodiment, the magnetization direction of the magnet sector is consistent with the magnetization direction of a standard two-dimensional Halbach array, and the magnetization direction is strictly maintained within the radial plane of the magnet sector.

[0010] Preferably, in one embodiment, the number of magnet sectors is an even number, preferably 8, 10, 12, or 16. The choice of the number of magnetic poles is related to the diameter of the magnetic ring and the target magnetic field strength: N=8 is suitable for small diameter scenarios with a diameter less than 100mm, N=12 is suitable for medium diameter scenarios with a diameter of 100mm to 200mm, and N=16 is suitable for large diameter scenarios with a diameter greater than 200mm.

[0011] Preferably, in one embodiment, the material of the magnet sector is neodymium iron boron permanent magnet material (such as N52, N42SH, etc.) or samarium cobalt permanent magnet material.

[0012] Preferably, in one embodiment, a shielding iron shell is further included, which is fitted over the outer side of the annular structure, with the inner wall of the shielding iron shell fitting against the outer wall of the annular structure. The shielding iron shell is made of low-carbon steel or electrical pure iron, with a thickness of 2mm-5mm, and is clearance-fitted with the outer wall of the annular structure, with a clearance of ≤0.1mm.

[0013] This application also provides a magnet sector, which is a single magnet sector in the above-described geometrically tilted three-dimensional Halbach magnetic ring assembly.

[0014] This application also provides a standardized fabrication method for a geometrically tilted three-dimensional Halbach magnetic ring assembly, comprising the following steps: Preferably, multiple magnet sectors are provided, each magnet sector having an inner surface and an outer surface. The inner surface is an inclined surface, and its normal forms a 30° angle with the radial direction of the magnet sector. The magnet sectors can be obtained using conventional permanent magnet manufacturing processes such as powder hot pressing or sintering. The machining accuracy of the inclined surface of the inner surface is ±0.1°.

[0015] Preferably, each magnet sector is placed in a tilting fixture, which has a bearing surface with a 30° tilt angle. The magnet sector rests on this bearing surface. The tilting fixture can be made of wood or plastic; the material itself is non-magnetic and will not interfere with the magnetization process. The tilting fixture has a V-groove or a flat bearing surface. The magnet sector is embedded in the V-groove or positioned on the flat bearing surface, and its position is maintained by a locating pin or a snap-fit. The tilt angle accuracy of the bearing surface of the tilting fixture is ±0.1°. The function of the tilting fixture is to maintain the stability of the magnet sector during magnetization and ensure the consistency of the magnetization angle.

[0016] Preferably, a standard unidirectional magnetizing field is used to magnetize the magnet sector. The direction of the unidirectional magnetizing field is consistent with the horizontal direction, so that the magnetization direction of the magnet sector is the Halbach array magnetization direction in a two-dimensional plane, and the magnetization direction is located in the radial plane of the magnet sector. The magnetization field strength of the standard unidirectional magnetizing field is 1T-3T, the number of magnetization pulses is 1-3, and the magnetization environment temperature is room temperature to 80°C. In this step, the magnetization direction is intentionally and strictly kept in a two-dimensional plane to ensure manufacturability.

[0017] Preferably, during magnetization, the tilting fixture places the magnet sector at a 60° angle relative to the magnetic field lines of the unidirectional magnetization field. This tilt angle results in a Z-axis magnetic field component being generated within the sector, even though the magnetization direction itself is in the horizontal plane, due to the tilt of the sector geometry.

[0018] Remove the tilting retainer to obtain the magnetized magnetic sector. The tilting retainer is only used as a temporary support during magnetization and is removed after magnetization is complete, without affecting the structure and performance of the final product.

[0019] Preferably, multiple magnetized magnetic sectors are arranged sequentially along the circumference, with each magnetic sector rotated 30° around its tangential axis. The tangential axis is perpendicular to the radial and axial directions of the magnetic sector. After rotation, the normals of each inner surface point to the central axis of the annular structure, so that each inner surface is aligned and spliced ​​to form a smooth annular inner hole wall, and each outer surface forms an annular outer wall with angular steps, thus producing a geometrically inclined three-dimensional Halbach magnetic ring assembly.

[0020] This application also provides a method for assembling a geometrically tilted three-dimensional Halbach magnetic ring assembly, comprising the following steps: providing multiple magnetic sectors as described above; arranging the multiple magnetic sectors sequentially along the circumferential direction, with each magnetic sector rotated 30° around its tangential axis, the tangential axis being perpendicular to the radial and axial directions of the magnetic sector, and after rotation, the normals of each inner surface pointing to the central axis of the annular structure, so that each inner surface is aligned and spliced ​​to form a smooth annular inner hole wall; fixing each magnetic sector by structural adhesive bonding, non-magnetic metal clamps, or positioning by limiting rings; and fitting a shielding iron shell around the annular structure to obtain the geometrically tilted three-dimensional Halbach magnetic ring assembly.

[0021] This application also provides a Halbach magnetic ring, which is assembled from the above-described geometrically tilted three-dimensional Halbach magnetic ring assembly, or assembled from a geometrically tilted three-dimensional Halbach magnetic ring assembly prepared by the standardized preparation method of the above-described geometrically tilted three-dimensional Halbach magnetic ring assembly.

[0022] The mechanism of this application is as follows: During magnetization, the magnet sector is placed in a tilted fixture, and its magnetization direction is strictly horizontal (radial plane). However, due to the tilt of the sector's geometry, the magnetization vector forms an acute angle with the inner surface normal in the sector's local coordinate system. During assembly, each sector is rotated around its tangential axis (which is perpendicular to both the radial and axial directions) by this acute angle. This causes the inner surface normal, which was originally tilted relative to the sector, to transform into a radial direction pointing towards the central axis of the magnetic ring in the spatial coordinate system. This geometric rotation decomposes the magnetization vector, originally in the radial plane, into a radial component and a Z-axis component in the spatial coordinate system. From the perspective of vector composition, if the tilt angle is θ, the Z-axis component is approximately sinθ times the original magnetization intensity, and the radial component is approximately cosθ times. By optimizing θ, the optimal balance between radial magnetization and the axial component can be achieved.

[0023] This application has the following beneficial technical effects: (1) This application designs the inner surface of the magnet sector as an inclined surface (forming a 30° angle with the radial direction). During assembly, each magnet sector is rotated 30° around its tangential axis, which is perpendicular to the radial and axial directions of the magnet sector. After rotation, the normal of each inner surface points to the central axis of the annular structure, making the inner surface parallel and aligned with the horizontal plane. Since the sector has an inclined geometry during manufacturing, it naturally produces an effective 30° inclination after being rotated and placed, thereby generating the required magnetic field component in the Z-axis direction without relying on complex three-dimensional magnetization technology.

[0024] (2) The magnetization process of this application adopts a standard unidirectional magnetization field, and the magnetization direction is completely consistent with the standard two-dimensional Halbach array, strictly kept in the radial plane. This greatly simplifies the magnetization process, which can be completed using only a simple wooden or plastic tilting fixture, without the need for special multidimensional magnetization coils, thus greatly reducing equipment costs and process complexity.

[0025] (3) In this application, the tilting fixture is used as a temporary support and is only used to keep the magnet sector stable during the magnetization process. It is removed after the magnetization is completed. This design ensures precise control of crystal orientation and magnetization direction during the magnetization process without affecting the structure and performance of the final product.

[0026] (4) This application achieves consistency between the magnetization direction and the crystal orientation through geometric design, avoiding the loss of magnetic performance caused by the inconsistency between the magnetization direction and the crystal orientation. The magnetization direction of each magnet sector is completely consistent with the magnetization direction of the standard two-dimensional Halbach array, and the crystal orientation is also arranged in the same direction, ensuring the maximization of magnet performance.

[0027] (5) The preparation method of this application achieves standardized production. All magnet sectors are prepared using the same tilting fixture and the same magnetization process. During assembly, it is only necessary to rotate and arrange each sector at a predetermined angle. The process has good consistency and is suitable for mass production. Tests show that the standard deviation of the Z-axis magnetic field strength of 10 samples in the same batch is only ±0.18mT.

[0028] (6) The outer surface of the assembled magnetic ring assembly forms an annular outer wall with angular steps. This geometry itself helps to converge and guide magnetic field lines, and works together with the internal inclined inner surface to further optimize the magnetic field distribution. Tests show that the magnetic field fluctuation in the Z-axis direction is ≤±2.5%, and the radial plane magnetic field strength reaches 0.045T.

[0029] (7) By optimizing the selection of a 30° tilt angle, this application achieves the best balance between radial magnetic field strength and Z-axis magnetic field component - ensuring radial magnetic focusing effect (radial magnetic field strength 45.0 mT, only 2.6% lower than the standard two-dimensional Halbach 46.2 mT) and obtaining sufficient Z-axis magnetic field component (18.5 mT), achieving unexpected comprehensive magnetic field performance. Attached Figure Description

[0030] Figure 1 This is a structural simulation diagram of the geometrically tilted three-dimensional Halbach magnetic ring assembly of this application; Figure 2 This is a schematic diagram of the internal three-dimensional Halbach arrangement magnetic rings and the external iron shell of the three-dimensional Halbach structure in the simulation model of this application; Figure 3 This is a schematic diagram of the internal Halbach arrangement magnetic rings and the external iron shell of the planar Halbach structure in the simulation model of this application; Figure 4 This is a three-dimensional Halbach magnetic circuit layout diagram of this application; Figure 5 This is a three-dimensional Halbach magnetic circuit diagram of this application, with the color scale representing the magnetic field strength distribution; Figure 6 The simulated magnetic field curve of the three-dimensional structure product of this application is shown in the figure. Detailed Implementation

[0031] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0032] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on the other component or there may be an intermediate component. When a component is considered to be "connected to" another component, it can be directly connected to the other component or there may be an intermediate component present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application's specification are for illustrative purposes only and do not represent the only possible implementation.

[0033] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. In the description of this application, "a plurality of" means at least two, such as two, three, etc., unless otherwise expressly and specifically defined.

[0034] Please see Figure 1 and Figure 2 , Figure 3 This application provides a geometrically tilted three-dimensional Halbach magnetic ring assembly, comprising multiple magnetic sectors arranged sequentially along the circumference to form a ring structure. Each magnetic sector has an inner surface and an outer surface. The inner surface is an inclined surface, and its normal forms a 30° angle with the radial direction of the magnetic sector. After the multiple magnetic sectors are assembled, the inner surfaces are aligned and spliced ​​to form a smooth annular inner wall, and the outer surfaces form an annular outer wall with angular steps. The magnetization direction of each magnetic sector is the Halbach array magnetization direction in a two-dimensional plane, located in the radial plane of the magnetic sector, and has a 30° angle with the normal direction of the inner surface.

[0035] The core design concept of this application lies in achieving the Z-axis magnetic field component through geometric tilting rather than magnetization direction tilting. Specifically, the inner surface of each magnet sector is designed as a tilted surface. During magnetization, the magnet sector is placed in a tilting fixture, the bearing surface of which forms a 30° angle with the horizontal plane. Magnetization is performed using a standard unidirectional magnetization field, with the magnetization direction consistent with the horizontal direction (i.e., the standard magnetization direction of a two-dimensional Halbach array). Because the magnet sector is tilted during magnetization, although its internal crystal orientation and magnetization direction are strictly maintained within the two-dimensional plane, a 30° angle is formed between the magnetization direction and the inner surface normal relative to the sector's own geometric coordinate system.

[0036] During the assembly stage, each magnetized sector is rotated 30° to align its inner surfaces and form a smooth annular inner wall. Because the sectors were manufactured with a tilted geometry, rotating them to a position where the inner surface is parallel to the horizontal plane naturally creates an effective 30° tilt. This geometric tilt causes the magnetization direction, originally in a two-dimensional plane, to have a Z-axis component in the spatial coordinate system, thus achieving the magnetic field effect of a three-dimensional Halbach magnetic ring.

[0037] Furthermore, the angle between the inner surface and the bottom surface of the magnet sector is 30°. The magnet sector is rotated 30° relative to the horizontal plane in the assembled state, ensuring that the inner surface is parallel to the horizontal plane. This design ensures the smooth continuity of the inner hole wall after assembly.

[0038] Furthermore, the magnetization direction of the magnet sector is consistent with the magnetization direction of a standard two-dimensional Halbach array, and the magnetization direction is strictly maintained within the radial plane of the magnet sector. This is the key difference between this application and traditional three-dimensional magnetization schemes—this application does not change the magnetization direction, but achieves the three-dimensional magnetic field effect only through geometric design.

[0039] Furthermore, the number of magnet sectors is even, preferably 8, 10, 12, or 16. An even number of sectors facilitates the symmetrical arrangement of the Halbach array. The choice of the number of magnetic poles is related to the diameter of the magnetic ring and the target magnetic field strength: N=8 is suitable for small-diameter scenarios with a diameter less than 100mm, N=12 is suitable for medium-diameter scenarios with a diameter of 100mm to 200mm, and N=16 is suitable for large-diameter scenarios with a diameter greater than 200mm. The material of the magnet sectors is neodymium iron boron permanent magnet material (such as N52, N42SH, etc.) or samarium cobalt permanent magnet material.

[0040] In one embodiment, the geometrically tilted three-dimensional Halbach magnetic ring assembly further includes a shielding iron shell, fitted over the outside of the annular structure, with the inner wall of the shielding iron shell fitting snugly against the outer wall of the annular structure. The shielding iron shell enhances the magnetic focusing effect and reduces magnetic field leakage. The shielding iron shell is made of low-carbon steel or electrical pure iron, with a thickness of 2mm-5mm, and is clearance-fitted with the outer wall of the annular structure, with a gap of ≤0.1mm.

[0041] This application also provides a standardized fabrication method for a geometrically tilted three-dimensional Halbach magnetic ring assembly, comprising the following steps: S1. Provides multiple magnet sectors, each with an inner and outer surface. The inner surface is an inclined surface, and its normal forms a 30° angle with the radial direction of the magnet sector. The magnet sectors can be obtained using conventional permanent magnet manufacturing processes such as powder hot pressing or sintering. The machining accuracy of the inclined surface of the inner surface is ±0.1°. S2. Place each magnet sector in the tilting fixture, which has a bearing surface with a 30° tilt angle. The magnet sector rests on this bearing surface. The tilting fixture can be made of wood or plastic; the material itself is non-magnetic and will not interfere with the magnetization process. The tilting fixture has a V-groove or a flat bearing surface. The magnet sector is embedded in the V-groove or positioned on the flat bearing surface, and its position is maintained by a locating pin or a clip. The tilt angle accuracy of the bearing surface of the tilting fixture is ±0.1°. The function of the tilting fixture is to maintain the stability of the magnet sector during magnetization and ensure the consistency of the magnetization angle.

[0042] S3. Magnetize the magnet sector using a standard unidirectional magnetizing field. The direction of the unidirectional magnetizing field is consistent with the horizontal direction, making the magnetization direction of the magnet sector the Halbach array magnetization direction in a two-dimensional plane, located in the radial plane of the magnet sector. The magnetization field strength of the standard unidirectional magnetizing field is 1T-3T, the number of magnetization pulses is 1-3, and the magnetization environment temperature is room temperature to 80°C. In this step, the magnetization direction is intentionally and strictly kept within a two-dimensional plane to ensure manufacturability.

[0043] During magnetization, the tilting fixture places the magnet sector at a 60° angle relative to the magnetic field lines of the unidirectional magnetization field. This tilt angle results in a Z-axis magnetic field component being generated within the sector, even though the magnetization direction itself is in the horizontal plane, due to the tilt of the sector's geometry.

[0044] S4. Remove the tilting fixture to obtain the magnetized magnet sector. The tilting fixture is only used as a temporary support during the magnetization process and is removed after magnetization is complete, without affecting the structure and performance of the final product.

[0045] S5. Arrange multiple magnetized magnetic sectors in sequence along the circumference. Rotate each magnetic sector 30° around its tangential axis. The tangential axis is perpendicular to the radial and axial directions of the magnetic sector. After rotation, the normals of each inner surface point to the central axis of the annular structure, so that each inner surface is aligned and spliced ​​to form a smooth annular inner hole wall, and each outer surface forms an annular outer wall with angular steps, thus obtaining a geometrically inclined three-dimensional Halbach magnetic ring assembly.

[0046] The core advantage of the above preparation method lies in the fact that all magnet sectors are prepared using the same tilting fixture and the same magnetization process, resulting in standardized preparation, good process consistency, and suitability for mass production. Since the magnetization direction and geometry of each sector are standardized, assembly only requires rotating and arranging each sector at a predetermined angle, resulting in high assembly accuracy and efficiency.

[0047] This application also provides a method for assembling a geometrically tilted three-dimensional Halbach magnetic ring assembly, comprising the following steps: providing multiple magnetic sectors as described above; arranging the multiple magnetic sectors sequentially along the circumferential direction, with each magnetic sector rotated 30° around its tangential axis, the tangential axis being perpendicular to the radial and axial directions of the magnetic sector, and after rotation, the normals of each inner surface pointing to the central axis of the annular structure, so that each inner surface is aligned and spliced ​​to form a smooth annular inner hole wall; fixing each magnetic sector by structural adhesive bonding, non-magnetic metal clamps, or positioning by limiting rings; and fitting a shielding iron shell around the annular structure to obtain the geometrically tilted three-dimensional Halbach magnetic ring assembly.

[0048] The following is a specific embodiment of the preparation method of the geometrically tilted three-dimensional Halbach magnetic ring assembly.

[0049] Example 1

[0050] A method for fabricating a geometrically tilted three-dimensional Halbach magnetic ring assembly includes the following steps: S1. Provides 12 magnet sectors, each manufactured using neodymium iron boron permanent magnet material (grade N52) through powder hot pressing. The outer diameter D of the magnetic ring is 200mm, and the axial height H is 100mm. Each magnet sector has an inner surface and an outer surface. The inner surface is an inclined surface, with its normal forming a 30° angle with the radial direction of the magnet sector. The machining accuracy of the inclined surface of the inner surface is ±0.1°.

[0051] S2. Place each magnet sector in the tilting retainer, which is made of plastic (PTFE) and has a V-groove bearing surface with a tilt angle of 30°. The magnet sector is embedded in the V-groove and its position is kept stable by locating pins. The tilt angle accuracy of the bearing surface of the tilting retainer is ±0.1°.

[0052] S3. Place the tilting fixture containing the magnet sector into the standard unidirectional magnetization device. Magnetize the magnet sector using a standard unidirectional magnetization field, with the direction of the unidirectional magnetization field aligned with the horizontal direction. The magnetization field strength is 2T, the number of magnetization pulses is 2, and the magnetization environment temperature is room temperature. The magnet sector is placed at a 60° angle relative to the magnetic field lines, and the magnetization direction is strictly maintained within the radial plane of the magnet sector.

[0053] S4. After magnetization is complete, remove the magnet sector from the tilting fixture to obtain the magnetized magnet sector.

[0054] S5. Arrange 12 magnetized magnetic sectors sequentially along the circumference. Rotate each magnetic sector 30° around its tangential axis, which is perpendicular to both the radial and axial directions of the sector. After rotation, the normals of each inner surface point to the central axis of the annular structure, aligning the inner surfaces to form a smooth annular inner wall and the outer surfaces to form an annular outer wall with stepped angles. Fix the magnetic sectors with structural adhesive. Finally, fit a shielding iron shell (made of low-carbon steel, 3mm thick, with a gap ≤0.1mm between the shell and the outer wall of the annular structure) around the annular structure to obtain a geometrically tilted three-dimensional Halbach magnetic ring assembly.

[0055] Example 2

[0056] A method for fabricating a geometrically tilted three-dimensional Halbach magnetic ring assembly includes the following steps: S1. Eight magnet sectors are provided, each manufactured using samarium cobalt permanent magnet material through sintering. The outer diameter D of the magnetic ring is 80 mm, and the axial height H is 50 mm. Each magnet sector has an inner surface and an outer surface. The inner surface is an inclined surface, with its normal forming a 30° angle with the radial direction of the magnet sector. The machining accuracy of the inclined surface of the inner surface is ±0.1°.

[0057] S2. Place each magnet sector in the tilting fixture, which is made of wood and has a flat bearing surface with a tilt angle of 30°. The magnet sector is positioned on the flat bearing surface and kept stable by clips. The tilt angle accuracy of the bearing surface of the tilting fixture is ±0.1°.

[0058] S3. The magnet sector is magnetized using a standard unidirectional magnetizing field, with the direction of the unidirectional magnetizing field aligned with the horizontal direction. The magnetizing field strength is 1.5T, the number of magnetizing pulses is 1, and the magnetizing ambient temperature is room temperature. The magnet sector is placed at a 60° angle relative to the magnetic field lines, and the magnetization direction is strictly maintained within the radial plane of the magnet sector.

[0059] S4. After magnetization is complete, remove the tilting fixture to obtain the magnetized magnet sector.

[0060] S5. Eight magnetized magnetic sectors are arranged sequentially along the circumference. Each magnetic sector is rotated 30° around its tangential axis, which is perpendicular to both the radial and axial directions of the sector. After rotation, the normals of the inner surfaces point to the central axis of the annular structure, aligning the inner surfaces to form a smooth annular inner wall and the outer surfaces to form an annular outer wall with stepped angles. The magnetic sectors are then fixed using non-magnetic metal clamps to obtain a geometrically tilted three-dimensional Halbach magnetic ring assembly.

[0061] Example 3

[0062] A method for fabricating a geometrically tilted three-dimensional Halbach magnetic ring assembly includes the following steps: S1. Provides 16 magnet sectors, each manufactured using neodymium iron boron permanent magnet material (grade N42SH) through sintering. The outer diameter D of the magnetic ring is 300mm, and the axial height H is 200mm. Each magnet sector has an inner surface and an outer surface. The inner surface is an inclined surface, with its normal forming a 30° angle with the radial direction of the magnet sector. The machining accuracy of the inclined surface of the inner surface is ±0.1°.

[0063] S2. Place each magnet sector in the tilting retainer, which is made of plastic (polyoxymethylene) and has a V-groove bearing surface with a tilt angle of 30°. The magnet sector is embedded in the V-groove and its position is kept stable by the positioning pin.

[0064] S3. The magnet sector is magnetized using a standard unidirectional magnetizing field, with the direction of the unidirectional magnetizing field aligned with the horizontal direction. The magnetizing field strength is 2.5T, the number of magnetizing pulses is 3, and the magnetizing ambient temperature is 60°C. The magnet sector is placed at a 60° angle relative to the magnetic field lines, and the magnetization direction is strictly maintained within the radial plane of the magnet sector.

[0065] S4. After magnetization is complete, remove the tilting fixture to obtain the magnetized magnet sector.

[0066] S5. Arrange 16 magnetized magnetic sectors sequentially along the circumference. Rotate each sector 30° around its tangential axis, which is perpendicular to both the radial and axial directions of the sector. After rotation, the normals of each inner surface point to the central axis of the annular structure, aligning the inner surfaces to form a smooth annular inner wall and creating an annular outer wall with stepped angles on the outer surfaces. Fix each magnetic sector using a positioning ring. Finally, fit a shielding iron shell (made of electrical pure iron, 5mm thick) around the annular structure to obtain a geometrically tilted three-dimensional Halbach magnetic ring assembly.

[0067] Comparative Example 1 A three-dimensional Halbach magnetic ring assembly was fabricated using a traditional three-dimensional magnetization method. Multidimensional magnetization coils were used to magnetize the magnetic sectors, with each sector's magnetization direction containing both radial and axial components. The magnetization equipment required a precise magnetic field control system. The magnetization process was complex, and the magnetization angle of each sector needed to be individually calibrated.

[0068] Comparative Example 2 A three-dimensional Halbach magnetic ring assembly was fabricated using an end-thickness compensation method. Compensating magnetic tiles of equal thickness (2 mm) were added to both ends of the standard two-dimensional Halbach magnetic ring along the Z-axis, with the magnetization direction of the compensating magnetic tiles aligned with the main magnet. This increased the axial length of the magnetic ring assembly by 4 mm and the overall weight by approximately 15%.

[0069] Comparative Example 3 Magnet sectors were prepared using different tilt angles (15° and 45°), and the remaining steps were the same as in Example 1.

[0070] Test case Test Example 1: Magnetic Field Distribution Test in the Z-Axis Direction The Z-axis magnetic field distribution of the geometrically tilted three-dimensional Halbach magnetic ring assembly prepared in Example 1 was tested. A three-dimensional gaussmeter (model: LakeShore475) was used for testing. The test probe measured point by point along the Z-axis (axial direction) of the magnetic ring assembly from one end to the other, with a measurement point interval of 5 mm. All measurement points were located on the central axis of the magnetic ring assembly. The test environment temperature was 25°C ± 1°C, and the relative humidity was ≤60%.

[0071] Test results show that the magnetic field strength is uniformly distributed along the Z-axis, without the gradient attenuation phenomenon of "high in the middle and low at both ends" observed in traditional 3D Halbach magnetic rings. The magnetic field fluctuation amplitude along the Z-axis is ≤±2.5%. Meanwhile, the magnetic field strength reaches 0.045T on the radial center plane (xoy plane) of the magnetic ring assembly, comparable to the magnetizing effect of a standard two-dimensional Halbach magnetic ring.

[0072] The above results show that, through geometric tilting design, this application successfully generated a uniform magnetic field component in the Z-axis direction of the magnetic ring assembly without changing the magnetization direction.

[0073] Test Example 2: Comparison Test at Different Tilt Angles To verify the basis for the selection of the 30° tilt angle in this application, three groups of magnet sector samples (12 sectors in each group) with tilt angles of 15°, 30° and 45° were prepared. They were prepared and magnetized using the same materials and processes as in Example 1, and their magnetic field performance was tested under the same test conditions after assembly.

[0074] The test results are shown in Table 1 below: Table 1

[0075] Test results show that at an inclination angle of 30°, the radial planar magnetic field strength reaches its maximum value of 45.0 mT, while the Z-axis magnetic field strength is 18.5 mT, achieving the optimal balance between the radial and axial magnetic fields. At an inclination angle of 15°, the Z-axis magnetic field component is insufficient, failing to meet the axial magnetic field requirements of the three-dimensional Halbach magnetic ring. At an inclination angle of 45°, although the Z-axis magnetic field component increases to 22.3 mT, the radial planar magnetic field strength decreases to 38.6 mT, and the magnetic field uniformity deteriorates. Therefore, 30° is the optimal inclination angle for this application.

[0076] Test Example 3: Consistency and Repeatability Test of Standardized Preparation Process Using the standardized preparation method of Example 1, 10 independent magnet sectors (all using a 30° tilting fixture and a 2T standard unidirectional magnetization field) were prepared in the same batch. The magnetization intensity, magnetization direction deviation, and Z-axis magnetic field strength of the assembled magnetic ring assembly of each sector were tested to verify the process consistency and feasibility of mass production of the standardized preparation method of this application.

[0077] The test results are shown in Table 2 below: Table 2

[0078] Test results show that the standard deviation of magnetization intensity in the 10 magnet sectors is only ±0.009T, the standard deviation of magnetization direction deviation is ±0.10°, and the standard deviation of Z-axis magnetic field intensity after assembly is ±0.18mT. The Z-axis magnetic field intensity of all samples is stable between 18.1mT and 18.7mT, with a fluctuation range of ≤±1.6%. This indicates that the standardized preparation method of this invention has excellent process consistency and fully meets the requirements of mass production.

[0079] Test Example 4: Comparison Test with Existing Technical Solutions To verify the superiority of this application over the prior art, magnetic field performance comparison tests were conducted on the magnetic ring assemblies prepared in Example 1 (geometric tilt of this application), Comparative Example 1 (three-dimensional magnetization), and Comparative Example 2 (end thickness compensation) under the same test conditions.

[0080] The test results are shown in Table 3 below.

[0081] Table 3

[0082] (1) Compared with Comparative Example 1 (three-dimensional magnetization): The magnetic field strength in the Z-axis direction of this application is slightly lower than that of the three-dimensional magnetization scheme (20.1 mT), with a difference of about 8%. However, the cost of the magnetization equipment in this application is only 1 / 5 to 1 / 8 of that of the three-dimensional magnetization scheme, and the magnetization time per unit is only 1 / 3 to 1 / 5 of that of the three-dimensional magnetization scheme. Under the premise of similar magnetic field performance, this application has significant advantages in terms of equipment cost and production efficiency.

[0083] (2) Compared with Comparative Example 2 (end thickness compensation): The magnetic field strength in the Z-axis direction of this application is about 47% higher than that in Comparative Example 2, the magnetic field fluctuation in the Z-axis direction is much better than that in Comparative Example 2, and the axial length of this application is not increased, while the axial length of Comparative Example 2 needs to be increased by about 4 mm.

[0084] Test Example 5: Temperature Stability Test To verify the magnetic field stability of the magnetic ring assembly of this application under different ambient temperatures, the geometrically tilted three-dimensional Halbach magnetic ring assembly prepared in Example 1 was placed in constant temperature environments of -20°C, 25°C (room temperature), 60°C, 80°C, and 120°C for 30 minutes, respectively, and its magnetic field strength in the Z-axis direction and radial plane magnetic field strength were tested. The test results are shown in Table 4.

[0085] Table 4

[0086] Test results show that within the operating temperature range of -20°C to 80°C, the magnetic field strength in the Z-axis direction remains above 17.4 mT, with a retention rate of ≥94%; the radial plane magnetic field strength remains above 42.3 mT, with a retention rate of ≥94%. At a high temperature of 120°C, the magnetic field strength retention rate is approximately 87.6%, still exhibiting usable magnetic field performance. These results demonstrate that the magnetic ring assembly of this application possesses good temperature stability within the normal operating temperature range, making it suitable for practical applications such as motors and sensors where temperature requirements are stringent.

[0087] Test Example 6: Long-term magnetic field decay test To verify the magnetic field retention capability of the magnetic ring assembly of this application, magnetic field strength tracking tests were conducted on the geometrically tilted three-dimensional Halbach magnetic ring assembly prepared in Example 1 at different time points after magnetization. The magnetic ring assembly was stored at room temperature (25°C±2°C), and its Z-axis magnetic field strength and radial plane magnetic field strength were measured at 1 day, 7 days, 30 days, 90 days, and 180 days after magnetization. The test results are shown in Table 5.

[0088] Table 5

[0089] Test results show that after 180 days (approximately 6 months) of storage at room temperature, the magnetic field strength along the Z-axis decreased from 18.5 mT to 17.9 mT, with a magnetic field retention rate of 96.8%; the radial plane magnetic field strength decreased from 45.0 mT to 43.8 mT, with a retention rate of 97.3%. Magnetic field decay mainly occurred in the initial period after magnetization (approximately 1.1% decay in the first 30 days), after which the decay rate slowed significantly (approximately 2.1% decay from 30 to 180 days). These results demonstrate that the magnetic ring assembly of this application possesses excellent long-term magnetic field retention capability, meeting the reliability requirements for long-term use.

[0090] Test Example 7: Test on the Influence of Different Numbers of Magnetic Poles on Magnetic Field Performance To verify the applicability of this application under different magnetic pole numbers, three sets of magnetic ring assemblies with magnetic pole numbers N=8 (Example 2), N=12 (Example 1), and N=16 (Example 3) were prepared respectively, and their magnetic field performance was compared under the same test conditions. The test results are shown in Table 6.

[0091] Table 6

[0092] Test results show that as the number of magnetic poles N increases, both the magnetic field strength along the Z-axis and the radial plane magnetic field strength increase, while the fluctuation of the Z-axis magnetic field decreases slightly. This indicates that the geometric tilt design scheme of this application can work effectively under different numbers of magnetic poles and has good universality. When N=8, the Z-axis magnetic field strength is 12.3 mT and the radial plane magnetic field strength is 38.5 mT; when N=16, the Z-axis magnetic field strength increases to 22.1 mT and the radial plane magnetic field strength increases to 48.6 mT. An appropriate number of magnetic poles can be selected according to the specific application scenario's requirements for magnetic field strength and magnetic ring size.

[0093] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A geometrically tilted three-dimensional Halbach magnetic ring assembly, characterized in that, include: Multiple magnetic sectors are arranged sequentially along the circumference to form a ring structure. Each magnetic sector has an inner surface and an outer surface. The inner surface is an inclined surface, and its normal forms a 30° angle with the radial direction of the magnetic sector. After the multiple magnet sectors are assembled, the inner surfaces of each sector are aligned and spliced ​​to form a smooth annular inner wall, and the outer surfaces of each sector form an annular outer wall with an angled step. The axis of the annular inner wall coincides with the axis of the magnetic ring assembly. The magnetization direction of each of the magnet sectors is the Halbach array magnetization direction in a two-dimensional plane. The magnetization direction is located in the radial plane of the magnet sector, and the magnetization direction has an angle of 30° with the normal direction of the inner surface. The angle between the inner surface of the magnet sector and the bottom surface of the magnet sector is 30°. The magnet sector is rotated 30° around its tangential axis in the assembled state. The tangential axis is perpendicular to the radial and axial directions of the magnet sector. After rotation, the normals of each inner surface point to the central axis of the annular structure so that each inner surface is spliced ​​to form the smooth annular inner hole wall. It also includes a shielding iron shell, which is fitted over the outside of the annular structure, with the inner wall of the shielding iron shell fitting against the outer wall of the annular structure.

2. The geometrically tilted three-dimensional Halbach magnetic ring assembly according to claim 1, characterized in that: The number of magnet sectors is an even number; the number is any one of 8, 10, 12, or 16.

3. The geometrically tilted three-dimensional Halbach magnetic ring assembly according to claim 1, characterized in that: The magnet sector is made of neodymium iron boron permanent magnet material or samarium cobalt permanent magnet material.

4. A magnetic sector, characterized in that, A single magnetic sector in the geometrically tilted three-dimensional Halbach magnetic ring assembly as described in any one of claims 1-3.

5. A standardized preparation method for a geometrically tilted three-dimensional Halbach magnetic ring assembly, characterized in that, Includes the following steps: Step 1: Provide multiple magnetic sectors, each magnetic sector having an inner surface and an outer surface, the inner surface being an inclined surface with its normal forming a 30° angle with the radial direction of the magnetic sector; place each magnetic sector in an inclined fixing device, the inclined fixing device having a bearing surface with an inclination angle of 30°, the magnetic sector being placed on the bearing surface; Step 2: Magnetize the magnet sector using a standard unidirectional magnetizing field. The direction of the standard unidirectional magnetizing field is consistent with the horizontal direction, so that the magnetization direction of the magnet sector is the Halbach array magnetization direction in a two-dimensional plane, and the magnetization direction is located in the radial plane of the magnet sector. Remove the tilting fixture to obtain the magnetized magnet sector; Step 3: Arrange multiple magnetized magnetic sectors sequentially along the circumference, with each magnetic sector rotated 30° around its tangential axis, which is perpendicular to the radial and axial directions of the magnetic sector. This allows the inner surfaces of each sector to be aligned and spliced ​​to form a smooth annular inner wall, and the outer surfaces to form an annular outer wall with angular steps, thus obtaining the geometrically inclined three-dimensional Halbach magnetic ring assembly.

6. The standardized preparation method of the geometrically tilted three-dimensional Halbach magnetic ring assembly according to claim 5, characterized in that: The tilting fastener is a wooden or plastic fastener, and it is removed after magnetization is completed. The tilting fixture has a V-groove or a flat bearing surface. The magnet sector is embedded in the V-groove or positioned on the flat bearing surface and is kept in a stable position by a positioning pin or a buckle.

7. The standardized preparation method of the geometrically tilted three-dimensional Halbach magnetic ring assembly according to claim 5, characterized in that: The magnet sector is a powder hot-pressed molded body or a sintered molded body; During the magnetization process, the tilting fixture causes the magnet sector to be tilted at 60° relative to the magnetic field lines of the unidirectional magnetization field. The machining accuracy of the inclined surface of the inner surface of the magnet sector is ±0.1°, and the inclination angle accuracy of the bearing surface of the inclined fixer is ±0.1°.

8. The standardized preparation method of the geometrically tilted three-dimensional Halbach magnetic ring assembly according to claim 5, characterized in that: The magnetization field strength of the standard unidirectional magnetization field is 1T-3T, the number of magnetization pulses is 1-3, and the magnetization environment temperature is room temperature to 80°C.

9. A method for assembling a geometrically tilted three-dimensional Halbach magnetic ring assembly, characterized in that, Includes the following steps: Multiple magnetic sectors are arranged sequentially along the circumferential direction. Each magnetic sector is rotated 30° around its tangential axis, which is perpendicular to the radial and axial directions of the magnetic sector, so that the inner surfaces are aligned and spliced ​​to form a smooth annular inner hole wall. Each of the magnet sectors is fixed by structural adhesive bonding, non-magnetic metal clamps, or positioning rings. A shielding iron shell is fitted over the outside of the annular structure to obtain the geometrically inclined three-dimensional Halbach magnetic ring assembly.

10. A Halbach magnetic ring, characterized in that, It is assembled from the geometrically tilted three-dimensional Halbach magnetic ring assembly as described in any one of claims 1-4, or from the geometrically tilted three-dimensional Halbach magnetic ring assembly prepared by the standardized preparation method of the geometrically tilted three-dimensional Halbach magnetic ring assembly as described in any one of claims 5-8.

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