Halbach magnet ring and production method

Abstract

The invention relates to a Halbach magnetic ring and a production method. The Halbach magnetic ring is provided with n antipodes, n is larger than or equal to 2, the angle of each antipode rotating a circle is 360 degrees, the angle of n antipodes rotating a circle is n * 360 degrees, the Halbach magnetic ring comprises n * 2m magnetic sheets, m is larger than or equal to 2, the n * 2m magnetic sheets are annularly arranged with the axis of the magnetic ring as the center, every m magnetic sheets form a magnetic sheet unit, m magnetic sheet units are annularly and evenly arranged, and the number of the magnetic sheets is larger than or equal to 2. An included angle formed by orientation directions of two adjacent magnetic sheets of each magnetic sheet unit is (n * 360 degrees) / (n * 2m), magnetic poles on one surface of the magnetic ring are alternately, annularly and uniformly arranged at intervals, and uniform and stable sine waves are formed on the surface of the magnetic ring. The method has the advantages that the surface magnetic field intensity is higher, and the waveform is optimized to be closer to a sinusoidal waveform.

Description

Technical Field

[0001] The present invention relates to a Halbach magnet ring and a production method thereof. Background Art

[0002] The existing planar quadrupole magnet rings are mainly formed by bonding magnets and ordinary sintered magnets magnetized into planar multipoles. The former has a better sine wave form, but the combination process is relatively complex and the structural strength is relatively low. The latter has a saddle-shaped waveform and has a lower magnetic field strength when the thickness of the magnet ring is the same. Summary of the Invention

[0003] The purpose of the present invention is to provide a Halbach magnet ring with a higher surface magnetic field strength and a waveform closer to the sine wave form.

[0004] To achieve the above purpose, the present invention adopts a Halbach magnet ring with n pairs of poles, n≥2. The angle of each pair of poles rotating one circle is 360°, and the angle of n pairs of poles rotating one circle is n×360°. It includes n×2m magnetic pieces, m≥2. The n×2m magnetic pieces are arranged in a ring centered on the axis of the magnet ring. Every m magnetic pieces form a magnetic piece unit, and m magnetic piece units are evenly arranged in a ring. The included angle formed by the orientation directions of two adjacent magnetic pieces in each magnetic piece unit is (n×360°)÷(n×2m). The magnetic poles on one side of the magnet ring are arranged alternately and evenly at intervals in a ring, and a uniform and stable sine wave is formed on the surface of the magnet ring.

[0005] By increasing the number of magnetic poles, a higher surface magnetic field strength can be achieved under the same size of the magnet ring; the increase in the number of pairs of poles makes the magnetic field distribution more uniform, the waveform closer to the ideal sine wave form, and reduces harmonic distortion; by adjusting the value of n, the magnet ring suitable for different application scenarios can be flexibly designed, such as high torque density motors or high-precision sensors. The present invention adopts a Halbach magnet ring, and the number of magnetic poles is selected according to actual needs to obtain a planar quadrupole or multipole magnet ring; the increase in the number of magnetic poles can make the sine wave effect on the surface of the magnet ring better.

[0006] By evenly distributing the magnetic pieces and setting specific orientation directions, the direction and intensity of the magnetic field can be precisely controlled; compared with the traditional multipole magnet ring, this layout can achieve a more complex magnetic field distribution with fewer magnetic bodies, reducing the material cost. At the same time, due to the setting of the orientation direction, the magnetic field on both sides of the magnet ring is uneven, which can make the magnetic field on one end face stronger and the sine wave effect better; among them, the larger m is, the closer the waveform formed on the surface is to the sine wave.

[0007] Among them, when the orientation direction of a magnetic piece unit is limited, and the magnetic poles are arranged alternately as NSNS, and to achieve a waveform closer to the sine wave form, the orientation directions and magnetization directions of other magnetic piece units will also be limited.

[0008] Preferably, n = 2 and m = 3. The orientation directions of the three magnetic disks of each magnetic disk unit form angles of 60°, 0°, and -60° with the extending direction of the magnetic ring axis.

[0009] When n = 2, the number of magnetic poles is small, which can avoid a more complex structure of the magnetizing coil, facilitate design and subsequent magnetization. When m = 3, it can avoid too small magnetic disks, facilitate the positioning and assembly between magnetic disks, facilitate ensuring the assembly accuracy, and ensure the magnetic performance of the magnetic ring after assembly.

[0010] Preferably, n = 2 and m = 3. The orientation directions of the three magnetic disks of each magnetic disk unit form angles of 90°, 30°, and -30° with the extending direction of the magnetic ring axis.

[0011] The setting of specific angles, that is, the setting of specific orientation directions and magnetization directions, can further optimize the magnetic field distribution, make it closer to the ideal sine wave form, and enhance the end face magnetic field intensity.

[0012] Preferably, the radius of the magnetic ring is 3 - 5 mm, and the width of the gap between adjacent magnetic disks is 0.07 - 0.25 mm. When the number of magnetic disks is restricted, the above magnetic disk gap can correct the waveform to make it closer to a sine wave.

[0013] Preferably, an isolator made of non-magnetic material is provided between adjacent magnetic disks, and adjacent magnetic disks do not contact each other. The non-magnetic material can prevent the magnetic fields between magnetic disks from interfering with each other and improve the independence of the magnetic field; the isolator can prevent direct contact between magnetic disks, maintain the gap between magnetic disks, and avoid structural deformation caused by magnetic attraction; through the isolation of the isolator, the magnetic field distribution is more uniform, and the phenomenon of local magnetic field enhancement or weakening is reduced.

[0014] Preferably, the isolator is in granular form and is fixed between adjacent magnetic disks by glue. The granular isolator fixed by glue can provide a more stable structure and prevent the magnetic disks from shifting during use.

[0015] Preferably, the magnetic disk is provided with a laterally extending protrusion, and the protrusion of one magnetic disk of adjacent two magnetic disks does not contact the other magnetic disk. By setting the protrusion, the thickness consistency of the glue on the axial side of the protrusion is better, preventing inconsistent glue thickness during the bonding process, and ensuring the structural strength and stability of the magnetic ring.

[0016] The present invention also discloses a production method for the above-mentioned Halbach magnetic ring, including the following steps: S1. Assemble 2n first magnets between two corresponding positioning pieces up and down; the positioning pieces have 2n positioning grooves arranged in a ring shape at uniform intervals, so that the ends of the first magnets are fitted in the positioning grooves to make the 2n first magnets arranged in a ring shape at uniform intervals, and a placement space is formed between adjacent two first magnets; S2. Place m - 1 second magnets at each placement space, such that the second magnets are restricted between the two positioning pieces. The angle formed by the orientation direction of the first magnet and the orientation direction of the adjacent second magnet is (n×360°)÷(n×2m). When the number of second magnets is at least two, the angle formed by the orientation directions of two adjacent second magnets is (n×360°)÷(n×2m); S3. Fix the first magnet, the second magnets and the positioning pieces with glue to obtain a magnetic ring blank; S4. Cut the magnetic ring blank to obtain the required Halbach magnetic ring.

[0017] The positioning groove design can ensure the precise assembly of the magnets, improve production efficiency and quality. Through the glue fixing and cutting processes, the traditional complex assembly procedures are simplified, the production cost is reduced, the assembly of the magnets is made more efficient, and the errors in manual operations are reduced; by cutting the longer magnets, more required magnetic rings can be obtained, which can greatly improve production efficiency. Among them, marks can be made on the first magnet and different magnets or different lengths can be selected to facilitate the identification of the magnets corresponding to the required orientation directions.

[0018] Preferably, in step S1, the positioning piece has the positioning groove that axially penetrates and laterally opens. The above setting facilitates the manufacture of the positioning piece, and at the same time allows the first magnet to be too long. The first magnet can be truncated according to actual needs, and it is convenient for the identification of the first magnet.

[0019] Preferably, in step S1, when the end of the first magnet is located in the positioning groove, there is a gap between the side wall of the end of the first magnet and the groove wall of the positioning groove, and glue is applied at the gap; in steps S3 and S4, heat - curable glue is applied at the joints of the first magnet, the second magnets and the positioning pieces. After baking with a heating device, grinding is carried out, and then slicing and electroplating are carried out.

[0020] The present invention has the advantages of higher surface magnetic field intensity and optimized waveform to make it closer to a sine wave. The present invention provides a reliable production method for small - size planar quadrupole magnetic rings. By using this method to manufacture planar quadrupole magnetic rings, the method is simple, multiple pieces can be produced at one time, and the production efficiency is greatly improved. Description of the Drawings

[0021] Figure 1 It is a side - view expanded view of the magnetization directions of 12 magnetic pieces of the Halbach magnetic ring according to Embodiment 2 of the present invention.

[0022] Figure 2 It is a side - view expanded view of the magnetization directions of 12 magnetic pieces of the Halbach magnetic ring according to Embodiment 3 of the present invention.

[0023] Figure 3 A structural schematic diagram of the present invention.

[0024] Figure 4 A structural schematic diagram of the positioning piece of the present invention.

[0025] Figure 5 A side-expanded view of the magnetization direction of the magnetic sheet of the magnetic ring blank in Embodiment 5 of the present invention.

[0026] Figure 6 A side-expanded view of the magnetization direction of the magnetic sheet of the magnetic ring blank in Embodiment 6 of the present invention.

[0027] Figure 7 A splicing finite element simulation diagram of Embodiment 2 of the present invention.

[0028] Figure 8 A splicing finite element simulation diagram of Embodiment 3 of the present invention.

[0029] Figure 9 A planar quadrupole waveform diagram of Embodiment 2 of the present invention.

[0030] Figure 10 A planar quadrupole waveform diagram of Embodiment 3 of the present invention. Specific embodiments

[0031] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0032] Embodiment 1 As Figure 3 shown, this embodiment discloses a Halbach magnetic ring, which has n pairs of poles, n≥2, the angle of each pair of poles turning one circle is 360°, the angle of n pairs of poles turning one circle is n×360°, and it includes n×2m magnetic sheets 100, m≥2. The n×2m magnetic sheets 100 are arranged in a ring centered on the magnetic ring axis. Every m magnetic sheets 100 form a magnetic sheet unit, and m magnetic sheet units are arranged evenly in a ring. The included angle formed by the orientation directions of two adjacent magnetic sheets 100 in each magnetic sheet unit is (n×360°)÷(n×2m). The magnetic poles on one side of the magnetic ring are arranged alternately and evenly at intervals in a ring, and a uniform and stable sine wave is formed on the surface of the magnetic ring Among them, the radius of the magnetic ring in this embodiment is 3-5 mm, and the width of the gap between two adjacent magnetic sheets 100 is 0.07-0.25 mm.

[0033] An isolator made of non-magnetic material is provided between two adjacent magnetic sheets 100, and two adjacent magnetic sheets 100 do not adhere to each other. The isolator is in the shape of particles and is fixed between two adjacent magnetic sheets 100 by glue; the isolator in this embodiment is made of glass particles, which has a lower cost. The magnetic sheet 100 is provided with a laterally extending protrusion 111, and the protrusion 111 of one magnetic sheet among two adjacent magnetic sheets 100 does not contact the other magnetic sheet.

[0034] Example 2 As shown by Figure 1 , Figure 7 and Figure 9 in the Halbach magnetic ring of this embodiment, n = 2, m = 3, and the orientation directions of the three magnetic sheets 100 of each magnetic sheet unit form angles of 60°, 0, and -60° with the extending direction of the magnetic ring axis. Among them, the thickness of the magnetic sheet 100 in this embodiment is 0.6 mm.

[0035] Example 3 As shown by Figure 2 , Figure 8 and Figure 10 in the Halbach magnetic ring of this embodiment, n = 2, m = 3, and the orientation directions of the three magnetic sheets 100 of each magnetic sheet unit form angles of 90°, 30°, and -30° with the extending direction of the magnetic ring axis. Among them, the thickness of the magnetic sheet 100 in this embodiment is 0.6 mm.

[0036] Example 4 This embodiment discloses a production method for the Halbach magnetic rings of Example 2 and Example 3, including steps S1 - S4.

[0037] S1: Assemble four first magnets 101 between two corresponding positioning sheets 200 up and down; the positioning sheet 200 has four positioning grooves 201 arranged at equal intervals in a ring shape, and the positioning grooves 201 axially penetrate the positioning sheet 200 and open to the circumferential outside; when the end of the first magnet 101 is located in the positioning groove 201, there is a gap between the side wall of the end of the first magnet 101 and the groove wall of the positioning groove 201, and glue is applied at the gap to form an adhesive layer 300, and the four first magnets 101 are arranged at equal intervals in a ring shape, and a placement space is formed between adjacent two first magnets 101; among them, the glue contains granular spacers made of non - magnetic materials, and the material of the spacers in this embodiment is glass.

[0038] S2: Fix two second magnets 102 together with glue, and the angle formed by the orientation directions of the two second magnets 102 is 60°, and then place the two fixed - together second magnets 102 at the placement space.

[0039] S3. Apply thermosetting glue at the combination of the second magnet 102, the first magnet 101, and the positioning sheet 200 to obtain a magnetic ring blank, bake the magnetic ring blank through a heating device, and then perform grinding processing on the magnetic ring blank; among them, the heating device is an oven.

[0040] S4. Cut off the end of the magnetic ring blank with the positioning sheet 200, and then slice and electroplate the magnetic ring blank according to the required thickness to obtain the required Halbach magnetic ring. Among them, the positioning sheet 200 is asFigure 4 As shown, the axial view of the Halbach magnetic ring after slicing is as Figure 3 shown.

[0041] Example 5 As Figure 5 shown, in the Halbach magnetic ring of this embodiment, n = 2, m = 2, and there are a total of 8 magnetic chips 100. The orientation directions of the two magnetic chips 100 in each magnetic chip unit form angles of 90° and 45° with the extension direction of the magnetic ring axis.

[0042] Example 6 As Figure 6 shown, in the Halbach magnetic ring of this embodiment, n = 2, m = 4, and there are a total of 16 magnetic chips 100. The orientation directions of the four magnetic chips 100 in each magnetic chip unit form angles of 90°, 45°, 0, and -45° with the extension direction of the magnetic ring axis.

[0043] The Halbach magnetic ring of this embodiment applies the Halbach principle to design a special magnetic chip arrangement and magnetization arrangement direction, which improves the peak value of the product waveform and also optimizes the waveform. It provides a reliable production method for small-size planar quadrupole magnetic rings. Using this method to manufacture planar quadrupole magnetic rings, the method is simple, multiple chips can be produced at one time, and the production efficiency is greatly improved.

Claims

1. A Halbach magnetic ring, having n pairs of poles, n ≥ 2, each pair of poles rotates through an angle of 360°, and n pairs of poles rotate through an angle of n×360°, characterized in that: It comprises n×2m magnetic sheets, m≥2, the n×2m magnetic sheets are arranged in a ring with the axis of the magnetic ring as the center, every m magnetic sheets constitute a magnetic sheet unit, the m magnetic sheet units are evenly arranged in a ring, the angle formed by the orientation directions of two adjacent magnetic sheets in each magnetic sheet unit is (n×360°)÷(n×2m), the magnetic poles on one side of the magnetic ring are evenly arranged in an alternating ring, and the surface of the magnetic ring forms a uniform and stable sine wave.

2. The Halbach magnetic ring according to claim 1, characterized in that: Said n=2, m=3, the orientation directions of the three magnetic sheets of each magnetic sheet unit and the extension direction of the axis of the magnetic ring form angles of 60°, 0°, and -60°.

3. The Halbach magnetic ring according to claim 1, characterized in that: Said n=2, m=3, the orientation directions of the three magnetic sheets of each magnetic sheet unit and the extension direction of the axis of the magnetic ring form angles of 90°, 30° and -30°.

4. The Halbach magnetic ring according to claim 1, characterized in that: The radius of the magnetic ring is 3-5 mm, and the width of the gap between two adjacent magnetic sheets is 0.07-0.25 mm.

5. The Halbach magnetic ring according to claim 1 or 4, characterized in that: An isolation piece made of non-magnetic conductive material is arranged between two adjacent magnetic sheets, so that the two adjacent magnetic sheets do not fit each other.

6. The Halbach magnetic ring according to claim 5, characterized in that: The isolation piece is in granular form and is fixed between two adjacent magnetic sheets by glue.

7. The Halbach magnetic ring according to claim 1 or 4, characterized in that: The magnetic sheet is provided with a protrusion extending laterally, and the protrusion of one magnetic sheet of two adjacent magnetic sheets does not contact the other magnetic sheet.

8. A method for producing the Halbach magnetic ring according to any one of claims 1 to 7, characterized in that The steps include: S1. Assemble 2n first magnets between two upper and lower corresponding positioning pieces; the positioning piece has 2n positioning grooves arranged evenly at intervals in an annular shape, so that the ends of the first magnets fit in the positioning grooves so that the 2n first magnets are arranged evenly at intervals in an annular shape, and a placement space is formed between two adjacent first magnets; S2. Place m-1 second magnets in each placement space so that the second magnets are confined between the two positioning plates. The angle formed by the orientation direction of the first magnet and the orientation direction of the adjacent second magnet is (n×360°)÷(n×2m). When the number of the second magnets is at least two, the angle formed by the orientation directions of the two adjacent second magnets is (n×360°)÷(n×2m). S3. Fixing the first magnet, the second magnet and the positioning sheet by glue to obtain a magnetic ring embryo; S4. Cut the magnetic ring embryo to obtain the required Halbach magnetic ring.

9. The method for producing a Halbach magnetic ring according to claim 8, characterized in that: In step S1 , the positioning piece has the positioning groove which penetrates axially and opens laterally.

10. The method for producing a Halbach magnetic ring according to claim 8, characterized in that: In step S1, when the end of the first magnet is located in the positioning groove, a gap is formed between the side wall of the end of the first magnet and the wall of the positioning groove, and the gap is coated with glue; In steps S3 and S4, heat-curing glue is applied to the joints of the first magnet, the second magnet and the positioning plate, and after being baked by a heating device, they are polished, sliced ​​and electroplated.

Images