Orientation device and orientation forming method of injection molding magnet

Abstract

The invention relates to the technical field of magnet orientation devices, and particularly discloses an orientation device and orientation forming method of an injection molding magnet, the orientation device comprises a permanent magnet, a magnetic conductive outer sleeve abutting against the periphery of the permanent magnet and a non-magnetic conductive inner sleeve abutting against the inner wall of the permanent magnet, and a circular mold cavity is formed in the middle of the non-magnetic conductive inner sleeve; the permanent magnet comprises an annular structure formed by connecting a first magnetic block and a second magnetic block which serve as repeating units end to end in a Halbach array arrangement mode. The shortest distance relation between the inner molded surfaces of the two magnetic blocks and the circle center of the mold and the curvature relation between the two inner molded surfaces are limited by adjusting the sizes of the first magnetic block and the second magnetic block and the distance rule between the inner molded surfaces and the wall of the mold cavity, so that the waveform of the orientation device is similar to sine waves when the orientation device is used for injection molding of a magnet with a wider magnetic pole; the waveform is smoother, the motor runs stably, and noise vibration is small.

Description

Technical Field

[0001] The invention relates to the technical field of magnet orientation devices, and in particular to an orientation device and an orientation molding method for injection-molded magnets. Background Art Magnet injection molding is an industrial method for producing permanent magnets. This method involves mixing magnetic powder with plastic or other binders, then producing the desired magnet shape through injection molding. Magnet injection molding is advantageous in producing small, high-precision magnetic components such as electromagnets, sensors, and speaker rings due to its ability to achieve complex geometric designs and high cost-effectiveness. Consequently, it is widely used in a variety of fields, including electronic equipment, motors, machinery manufacturing, medical equipment, and the automotive industry.

[0002] Orientation in magnet injection molding technology involves aligning magnetic domains in a specific direction within the adhesive, thereby fully utilizing the material's magnetic properties. Orientation methods primarily include permanent magnet orientation and electromagnetic orientation. Permanent magnet orientation is typically achieved using a Halbach array. This arrangement arranges magnets in a pattern that enhances the magnetic field on one side of the array while significantly weakening or even canceling it on the other. This arrangement typically involves alternating the north and south poles of the magnets, concentrating the magnetic field on one side of the array.

[0003] At present, the traditional single-sided magnetic field enhanced multi-pole annular Halbach array structure divides the annular magnet into multiple sector-shaped magnetic blocks with the same geometric shape. These magnetic blocks are arranged and combined through different magnetization directions to form a specific magnetic field distribution, and are assembled in subsequent steps. However, for injection-molded magnets with wider magnetic poles, the traditional Halbach permanent magnet array orientation device has some limitations in application. The magnetic field waveform of the injection-molded magnets produced using this device often presents a square wave or saddle waveform. The unevenness of this waveform will cause torque fluctuations in the motor made of these magnets during operation, which will affect the smooth operation of the motor and generate a lot of noise. Summary of the Invention

[0004] The purpose of the present invention is to overcome the problem of low smoothness of the magnetic field waveform of injection-molded magnets produced by traditional orientation devices containing Halbach array structures in the prior art, and to provide an orientation device and orientation molding method for injection-molded magnets. The present invention makes targeted design adjustments to the structure of the permanent magnet, designing the minimum circulation unit of the permanent magnet into structures with different volume sizes and different distances from the inner surface to the mold cavity, so that the orientation device has a smoother air gap magnetic field. When injection molding magnets with wider magnetic poles, the waveform is a quasi-sine wave; the waveform is smoother, the motor runs smoothly, and the noise and vibration are reduced.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions: An orientation device for an injection-molded magnet, comprising: A permanent magnet, wherein the permanent magnet comprises a first magnetic block and a second magnetic block as repeating units connected end to end in a Halbach arrangement to form a ring structure; A magnetic conductive outer sleeve, which is wound around the outer side of the permanent magnet; a non-magnetic inner sleeve, the non-magnetic inner sleeve abutting against the annular inner wall of the permanent magnet; A circular mold cavity is provided in the middle of the non-magnetic inner sleeve, and the circular mold cavity is used to contain the injection molding magnet melt; Wherein, the volume of the first magnetic block is not equal to the volume of the second magnetic block; The shortest distance from the first inner surface of the first magnetic block to the mold cavity wall is smaller than the shortest distance from the second inner surface of the second magnetic block to the mold cavity wall; The shortest distance r from the first inner surface of the first magnetic block to the center of the mold and the shortest distance R from the second inner surface of the second magnetic block to the center of the mold have the following relationship: R / r≥1; The curvature K1 of the first inner surface of the first magnetic block and the curvature K2 of the second inner surface of the second magnetic block have the following relationship: K1 / K2<0.2.

[0006] The orientation device for injection-molded magnets provided in the present application includes a permanent magnet, a magnetic outer sleeve abutting against the periphery of the permanent magnet, and a non-magnetic inner sleeve abutting against the inner wall of the permanent magnet, wherein a circular mold cavity is provided in the middle of the non-magnetic inner sleeve; at the same time, the structure of the permanent magnet is designed and adjusted in a targeted manner, wherein the permanent magnet includes a first magnetic block and a second magnetic block as a repeating unit connected end to end in a Halbach arrangement to form a ring structure, wherein the volume of the first magnetic block is not equal to the volume of the second magnetic block; the shortest distance from the inner surface of the first magnetic block to the mold cavity wall is less than the shortest distance from the inner surface of the second magnetic block to the mold cavity wall. By adjusting the size of the first magnetic block and the second magnetic block and the distance rule from the inner surface to the mold cavity wall, the shortest distance relationship between the inner surface of the two magnetic blocks and the center of the mold circle and the curvature relationship of the two inner surfaces are limited, so that when the orientation device is used for injection molding a magnet with a wider magnetic pole, its waveform is a quasi-sine wave; the waveform is smoother, the motor runs smoothly, and the noise and vibration are small.

[0007] Furthermore, the shortest distance r from the first inner surface of the first magnetic block to the center of the mold and the shortest distance R from the second inner surface of the second magnetic block to the center of the mold have the following relationship: 1.05≤R / r≤1.4.

[0008] Furthermore, the outer diameter od of the circular mold cavity and the pole pair number 2*p of the orientation device have the following relationship: od*π / (2*p)>5 mm.

[0009] Furthermore, the first inner surface of the first magnetic block is a straight surface or a curved surface, the second inner surface of the second magnetic block is a straight surface or a curved surface, and among the contact points of the first magnetic block and the second magnetic block, the point with the shortest distance from the center of the mold is located on the inner surface.

[0010] Furthermore, the first magnetic block and the second magnetic block are sector-shaped magnetic blocks, and the central angle of the first magnetic block is 20° to 60°.

[0011] Furthermore, the permanent magnets are arranged in a clockwise direction in a cycle of 0° magnetization, 90° magnetization, 180° magnetization and 270° magnetization; The first magnetic block is magnetized at 0° or 180°, and the second magnetic block is magnetized at 90° or 270°.

[0012] Furthermore, the number of pole pairs of the orientation device is 2 to 4 pole pairs.

[0013] Furthermore, the magnetic conductive jacket is made of a material with an initial relative magnetic permeability greater than 50 and a saturation magnetization intensity greater than 1T. The non-magnetic inner sleeve is made of a material with an initial relative magnetic permeability of less than 10.

[0014] Another object of the present invention is to protect a method for orientation molding using the above-mentioned orientation device.

[0015] A method for orientation molding using the orientation device for injection molding magnets as described above comprises the following steps: Step 1: Assemble the orientation device of the injection-molded magnet, and install the assembled orientation device in an injection mold frame to form an injection mold; Step 2: Installing the injection mold in an injection molding device; Step 3: The injection molding melt is injected into the injection mold by an injection molding machine for molding. During the molding process, the injection molding magnet melt is oriented under the action of the magnetic field in the orientation device to obtain the injection molding magnet.

[0016] Compared with the prior art, the present invention has the following beneficial effects: The orientation device for injection-molded magnets provided in the present application includes a permanent magnet, a magnetic outer sleeve abutting against the periphery of the permanent magnet, and a non-magnetic inner sleeve abutting against the inner wall of the permanent magnet, wherein a circular mold cavity is provided in the middle of the non-magnetic inner sleeve; at the same time, the structure of the permanent magnet is designed and adjusted in a targeted manner, wherein the permanent magnet includes a first magnetic block and a second magnetic block as a repeating unit connected end to end in a Halbach arrangement to form a ring structure, wherein the volume of the first magnetic block is not equal to the volume of the second magnetic block; the shortest distance from the inner surface of the first magnetic block to the mold cavity wall is less than the shortest distance from the inner surface of the second magnetic block to the mold cavity wall. By adjusting the size of the first magnetic block and the second magnetic block and the distance rule from the inner surface to the mold cavity wall, the shortest distance relationship between the inner surface of the two magnetic blocks and the center of the mold circle and the curvature relationship of the two inner surfaces are limited, so that when the orientation device is used for injection molding a magnet with a wider magnetic pole, its waveform is a quasi-sine wave; the waveform is smoother, the motor runs smoothly, and the noise and vibration are small. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 This is a schematic structural diagram of an orientation device with two pole pairs according to the present invention.

[0017] Figure 2 This is a schematic structural diagram of an orientation device with three pole pairs according to the present invention.

[0018] Figure 3 This is a schematic structural diagram of an orientation device with four pole pairs according to the present invention.

[0019] Figure 4 Schematic diagram of the magnetization direction of the magnetic block in the permanent magnet.

[0020] Figure 5 : is the air gap magnetic field waveform diagram of the orientation device in the embodiment.

[0021] Markings in the figure: 1-permanent magnet, 11-first magnetic block, 12-second magnetic block, 2-magnetic outer sleeve, 3-non-magnetic inner sleeve, 4-circular mold cavity, 41-mold cavity wall, 5-first inner surface, 6-second inner surface. DETAILED DESCRIPTION

[0022] The present invention will be further described in detail below in conjunction with test examples and specific embodiments. However, this should not be understood as limiting the scope of the present invention to the following embodiments, and all technologies implemented based on the present invention fall within the scope of the present invention.

[0023] Unless otherwise specified, terms indicating orientation or positional relationships such as "upper," "lower," "left," "right," "center," "inside," and "outside" in the description of specific embodiments of the present invention are based on the orientation or positional relationships shown in the accompanying drawings, or are the orientation or positional relationships in which the inventive product / device / apparatus is typically placed during use. These terms indicating orientation or positional relationships are merely intended to facilitate description of the present invention or to simplify the description of specific embodiments, so as to facilitate quick understanding of the solutions by technicians. They do not indicate or imply that a particular device / component / element must have a specific orientation or be constructed and operated in a specific positional relationship, and therefore should not be construed as limiting the present invention.

[0024] In addition, if the terms "horizontal", "vertical", "overhanging", "parallel" and the like appear, it does not mean that the corresponding devices / components / elements are required to be absolutely horizontal or vertical or overhanging or parallel, but may be slightly tilted or have deviations. For example, "horizontal" only means that its direction is more horizontal relative to "vertical", and does not mean that the structure must be completely horizontal, but may be slightly tilted. Alternatively, it can be simply understood that the corresponding devices / components / elements are set in directions such as "horizontal", "vertical", "overhanging", and "parallel", and can have an error / deviation of ±10% relative to the corresponding direction setting, more preferably an error / deviation within ±8%, more preferably an error / deviation within ±6%, more preferably an error / deviation within ±5%, and more preferably an error / deviation within ±4%. As long as the corresponding device / component / element is within the error / deviation range, it can still achieve its role in the solution of the present invention.

[0025] In addition, the expressions "first", "second", "third", etc. that appear in the terms are merely descriptions used to distinguish the same or similar components and should not be understood as emphasizing or implying the relative importance of specific components.

[0026] In addition, in the description of the embodiments of the present invention, "several," "plurality," and "a number" represent at least two. It can also be any number such as two, three, four, five, six, seven, eight, nine, or even more than nine.

[0027] Furthermore, in the description of the technical solution of the present invention, unless otherwise expressly specified, defined, or limited, the terms "disposed," "installed," "connected," "connected," "provided with," "laid," and "arranged" should be understood broadly. For example, they may refer to fixed connections, detachable connections, or integral connections. They may be welded, riveted, bolted, threaded, or other commonly used connection methods in the art. Such connections may be mechanical, electrical, or communicative; they may be direct, indirect via an intermediate medium, or internally connected between two components.

[0028] The traditional single-sided magnetic field enhanced multi-pole annular Halbach array structure divides the annular magnet into multiple sector-shaped magnetic blocks with the same geometric shape. These magnetic blocks are arranged and combined in different magnetization directions to form a specific magnetic field distribution and are assembled in subsequent steps. However, for injection-molded magnets with wider magnetic poles, the traditional Halbach permanent magnet array orientation device has some limitations in application. The magnetic field waveform of the injection-molded magnets produced using this device often presents a square wave or saddle waveform. The unevenness of this waveform will cause torque fluctuations in the motor made of these magnets during operation, which will affect the smooth operation of the motor and generate a lot of noise.

[0029] For this reason, Figures 1-4 As shown, an orientation device for injection-molded magnets includes: a permanent magnet 1, wherein the permanent magnet 1 includes a first magnetic block 11 and a second magnetic block 12 as a repeating unit connected end to end in a Halbach arrangement to form a ring structure; A magnetic conductive jacket 2, which is wound around the outside of the permanent magnet 1; a non-magnetic inner sleeve 3 , the non-magnetic inner sleeve 3 abutting against the annular inner wall of the permanent magnet 1 ; A circular mold cavity 4 is provided in the middle of the non-magnetic inner sleeve 3, and the circular mold cavity 4 is used to contain the injection molding magnet melt; Wherein, the volume of the first magnetic block 11 is not equal to the volume of the second magnetic block 12; The shortest distance from the first inner surface 5 of the first magnetic block 11 to the mold cavity wall 41 is smaller than the shortest distance from the second inner surface 6 of the second magnetic block 12 to the mold cavity wall 41; The shortest distance r from the first inner surface 5 of the first magnetic block 11 to the center of the mold and the shortest distance R from the second inner surface 6 of the second magnetic block 12 to the center of the mold have the following relationship: R / r≥1; The curvature K1 of the first inner surface 5 of the first magnetic block 11 and the curvature K2 of the second inner surface 6 of the second magnetic block 12 have the following relationship: K1 / K2<0.2.

[0030] The orientation device for injection-molded magnets provided in the present application limits the shortest distance relationship between the inner surfaces of the two magnetic blocks and the center of the mold and the curvature relationship of the two inner surfaces by adjusting the size of the first magnetic block and the second magnetic block and the distance rule from the inner surface to the mold cavity wall. This allows the orientation device to have a waveform that is quasi-sine wave when injection-molding a magnet with a wider magnetic pole; the waveform is smoother, the motor runs smoothly, and the noise and vibration are small.

[0031] Furthermore, the shortest distance r from the first inner surface 5 of the first magnetic block 11 to the mold center and the shortest distance R from the second inner surface 6 of the second magnetic block 12 to the mold center have the following relationship: 1.05≤R / r≤1.4.

[0032] In some embodiments, the outer diameter od of the circular mold cavity 4 and the number of pole pairs 2*p of the orientation device have the following relationship: od*π / (2*p) > 5 mm. A larger arc length corresponding to each magnetic pole pair in the orientation device on the mold's outer diameter, i.e., a larger spacing between the magnetic poles, leads to uneven magnetic field distribution within the magnet, forming regions of lower magnetic field intensity between the poles. However, the orientation device provided in this application produces a quasi-sine wave waveform when injection molding magnets with wider poles. This smoother waveform results in stable motor operation with minimal noise and vibration.

[0033] In some embodiments, the first inner surface 5 of the first magnetic block 11 is a straight surface or a curved surface, and the second inner surface 6 of the second magnetic block 12 is a straight surface or a curved surface. Among the contact points of the first magnetic block and the second magnetic block, the point with the shortest distance from the center of the mold is located on the inner surface. Preferably, when the second inner surface 6 of the second magnetic block 12 is a curved surface, the orientation effect of the orientation device is better. When the inner surface is a straight surface, the curvature K1 is infinitely small. The second inner surface 6 of the second magnetic block is a curved surface with a radius of R and a curvature of K2. The difference between K1 and K2 is large, and the orientation effect of the orientation device is more prominent. The shortest distance r from the centerline of the inner surface of the first magnetic block to the center of the mold and the shortest distance R from the inner surface of the second magnetic block to the center of the mold have the following relationship: R / r≥1, preferably 1.05≤R / r≤1.4. The curvature K1 of the inner surface of the first magnetic block and the curvature K2 of the inner surface of the second magnetic block have the following relationship: K1 / K2<0.2.

[0034] In some embodiments, the first magnetic block 11 and the second magnetic block 12 are sector-shaped magnetic blocks, and the central angle of the first magnetic block 11 is 20° to 60°. Within this angle range, the surface magnetic peak of the orientation device can be maintained at a high level, and the waveform is relatively smooth.

[0035] In some embodiments, the permanent magnet 1 is arranged in a clockwise direction in a cycle of 0° magnetization, 90° magnetization, 180° magnetization and 270° magnetization; the first magnetic block 11 is 0° magnetization or 180° magnetization, and the second magnetic block 12 is 90° magnetization or 270° magnetization.

[0036] In some embodiments, the orientation device has a pole pair count of 2 to 4 pairs of poles. The pole pair count of an orientation device refers to the number of magnetic pole pairs in the magnetic field device used to orient the magnets during the injection molding process. The pole pair count determines the spatial distribution of the magnetic field generated by the orientation device. The present invention improves the magnetic circuit arrangement and geometry of the annular Halbach magnets in orientation devices with fewer pole pairs, resulting in a smoother air gap magnetic field. This addresses issues that are difficult to address with conventional orientation devices in the prior art with fewer pole pairs.

[0037] Furthermore, the magnetic conductive outer sleeve 2 is made of a material with an initial relative magnetic permeability greater than 50 and a saturation magnetization intensity greater than 1T, and the non-magnetic conductive inner sleeve 3 is made of a material with an initial relative magnetic permeability less than 10.

[0038] The method for orientation molding using the orientation device for injection molding magnets as described above comprises the following steps: Step 1: Assemble the orientation device of the injection-molded magnet and install the assembled orientation device in the injection mold frame to form a set of injection molds; Step 2: Installing the injection mold in an injection molding device; Step 3: The injection molding melt is injected into the injection mold by an injection molding machine for molding. During the molding process, the injection molding magnet melt is oriented under the action of the magnetic field in the orientation device to obtain the injection molding magnet.

[0039] To this end, the alignment devices of Example 1 and Comparative Example 1 were provided, and the air gap magnetic field waveform of the alignment devices was tested, as shown in FIG. Figure 5 shown.

[0040] The specific structure is as follows: Example 1 like Figure 1 As shown, Example 1 provides an orientation device with a pole pair number of 2 pairs of poles, specifically comprising: a permanent magnet 1, wherein the permanent magnet 1 comprises a first magnetic block 11 and a second magnetic block 12 as repeating units, which are connected end to end in a Halbach arrangement to form a ring structure; wherein the volume of the first magnetic block 11 is greater than the volume of the second magnetic block 12. There are 4 repeating units in total, four first magnetic blocks 11, and four second magnetic blocks 12. The eight magnetic blocks are arranged in a clockwise direction in a cycle of 0° magnetization, 90° magnetization, 180° magnetization, and 270° magnetization, wherein the first magnetic block 11 is 0° magnetization or 180° magnetization, and the second magnetic block 12 is 90° magnetization or 270° magnetization. Two pairs of poles are formed.

[0041] The outer diameter od of the circular mold cavity 4 is 30 mm, the number of pole pairs of the orientation device is 2, od*π / (2*p) is 23.55 mm, and the orientation device has a wider magnetic pole.

[0042] The first magnetic block 11 and the second magnetic block 12 are sector-shaped magnetic blocks. The shortest distance from the first inner surface 5 of the first magnetic block 11 to the mold center is r, and the shortest distance from the second inner surface 6 of the second magnetic block 12 to the mold center is R, with R / r being 1.11. A magnetic outer sleeve 2 is wound around the outside of the permanent magnet 1 and is made of magnetic steel. A non-magnetic inner sleeve 3 is abutted against the annular inner wall of the permanent magnet 1 and is made of a non-magnetic alloy. A circular mold cavity 4 is provided in the center of the non-magnetic inner sleeve 3 for containing the injection molding magnet melt.

[0043] Comparative Example 1 Comparative Example 1 uses a conventional Halbach array arrangement orientation device, specifically Figure 1 On the basis of the first magnetic block 11 and the second magnetic block 12, the volume and geometric shape are consistent, the annular structure is divided into 8 structures, the inner surfaces of the first magnetic block and the second magnetic block are both arc surfaces, the inner wall of the entire annular structure is circular, and the curvature radius of the first magnetic block and the second magnetic block is set to Figure 1 R in.

[0044] test: The alignment devices of Example 1 and Comparative Example 1 were tested for magnetic field strength (T).

[0045] The specific test process is as follows: Place the finished orientation device on a special magnetization characteristic measuring instrument to test its surface magnetic waveform curve. The surface magnetic curve obtained is as follows: Figure 5 shown.

[0046] The test results are as follows Figure 5 As shown in Figure 1, Curve 1 shows the magnetic flux density waveform of an orientation device manufactured using the method proposed in this patent, while Curve 2 shows the magnetic flux density waveform of an orientation device manufactured using a conventional Halbach array. A comparison of the two curves demonstrates that the method proposed in this patent effectively improves the smoothness of the surface magnetic waveform, resulting in a smoother waveform than that of an orientation device manufactured using a conventional Halbach array. Consequently, motors manufactured using this orientation device run more smoothly with less noise and vibration.

[0047] The above description is only 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 in the scope of protection of the present invention.

Claims

1. An orientation device for injection-molded magnets, characterized in that: include: A permanent magnet (1), comprising a first magnetic block (11) and a second magnetic block (12) as repeating units connected end to end in a Halbach arrangement to form a ring structure; A magnetic conductive outer sleeve (2), the magnetic conductive outer sleeve (2) being wound around the outside of the permanent magnet (1); A non-magnetic inner sleeve (3), the non-magnetic inner sleeve (3) abutting against the annular inner wall of the permanent magnet (1); A circular mold cavity (4) is provided in the middle of the non-magnetic inner sleeve (3), and the circular mold cavity (4) is used to contain the injection molding magnet melt; Wherein, the volume of the first magnetic block (11) is not equal to the volume of the second magnetic block (12); The shortest distance between the first inner profile (5) of the first magnetic block (11) and the mold cavity wall (41) is smaller than the shortest distance between the second inner profile (6) of the second magnetic block (12) and the mold cavity wall (41); The shortest distance r from the first inner surface (5) of the first magnetic block (11) to the center of the mold and the shortest distance R from the second inner surface (6) of the second magnetic block (12) to the center of the mold have the following relationship: R / r≥1; The curvature K1 of the first inner surface (5) of the first magnetic block (11) and the curvature K2 of the second inner surface (6) of the second magnetic block (12) have the following relationship: K1 / K2<0.

2.

2. The orientation device for injection molded magnets according to claim 1, wherein The shortest distance r from the first inner surface (5) of the first magnetic block (11) to the center of the mold and the shortest distance R from the second inner surface (6) of the second magnetic block (12) to the center of the mold have the following relationship: 1.05≤R / r≤1.

4.

3. The orientation device for injection molded magnets according to claim 1, wherein The outer diameter od of the circular mold cavity (4) and the number of pole pairs 2*p of the orientation device have the following relationship: od*π / (2*p)>5 mm.

4. The orientation device for injection-molded magnets according to claim 1, wherein: The first inner surface (5) of the first magnetic block (11) is a straight surface or a curved surface, the second inner surface (6) of the second magnetic block (12) is a straight surface or a curved surface, and among the contact points of the first magnetic block (11) and the second magnetic block (12), the point with the shortest distance from the center of the mold is located on the inner surface.

5. The orientation device for injection-molded magnets according to claim 4, characterized in that: The first magnetic block (11) and the second magnetic block (12) are sector-shaped magnetic blocks, and the central angle of the first magnetic block (11) is 20° to 60°.

6. The orientation device for injection-molded magnets according to claim 1, characterized in that: The permanent magnets (1) are arranged in a clockwise direction in a cycle of 0° magnetization, 90° magnetization, 180° magnetization, and 270° magnetization; the first magnetic block (11) is 0° magnetization or 180° magnetization, and the second magnetic block (12) is 90° magnetization or 270° magnetization.

7. The orientation device for injection-molded magnets according to claim 2, characterized in that: The number of pole pairs of the orientation device is 2 to 4 pole pairs.

8. The orientation device for injection-molded magnets according to any one of claims 1 to 7, characterized in that: The magnetic conductive jacket (2) is made of a material with an initial relative magnetic permeability of >50 and a saturation magnetization intensity of >1T. The non-magnetic inner sleeve (3) is made of a material with an initial relative magnetic permeability of less than 10.

9. A method for orientation molding using the orientation device for injection-molded magnets according to any one of claims 1 to 8, characterized in that: The following steps are involved: Step 1: Assemble the orientation device for the injection-molded magnet according to any one of claims 1 to 8, and install the assembled orientation device in an injection mold frame to form a set of injection molds; Step 2: Installing the injection mold in an injection molding device; Step 3: The injection molding melt is injected into the injection mold by an injection molding machine for molding. During the molding process, the injection molding magnet melt is oriented under the action of the magnetic field in the orientation device to obtain the injection molding magnet.

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