Centrifugal auxiliary curing bonded magnet radial gradient magnetic powder distribution device and method

Abstract

The invention discloses a centrifugal auxiliary curing bonded magnet radial gradient magnetic powder distribution device and method.The centrifugal auxiliary curing bonded magnet radial gradient magnetic powder distribution device comprises a centrifugal barrel unit serving as a slurry container, and the centrifugal barrel unit comprises a centrifugal barrel body, a first end cover and a second end cover; the transmission system is implemented by regulating the rotating speed of the centrifugal barrel unit; the heating curing device surrounds the outer ring of the centrifugal barrel unit; by optimizing a centrifugal distribution curing device and technological parameters, integrated forming of magnetic powder gradient distribution and epoxy resin curing is achieved, segmentation or secondary processing is not needed, efficiency is improved, the manufactured magnet has the high interface bonding force and high compactness, the special magnetic performance requirement is met, the centrifugal barrel is flexible in design and adapts to different taking-out requirements, and the manufacturing cost is reduced. The magnetic powder is gathered on the outer ring under the assistance of centrifugal rotation, the magnetic induction intensity of the outer ring is higher than that of the inner ring, and due to the magnetic powder distribution structure, the magnet shows higher magnetic induction intensity under the limited volume and magnetic powder content, and the requirements of various working conditions are met.

Description

Technical Field

[0001] The present invention relates to a device and method for radial gradient magnetic powder distribution of bonded magnets, and particularly to a device and method for radial gradient magnetic powder distribution of bonded magnets with centrifugal-assisted curing. Background Art

[0002] Bonded magnets are functional materials composed of magnetic powders and polymer binders. They combine adjustable magnetic properties and flexible molding characteristics, and are widely used in precision electromagnetic devices such as motors, sensors, and permanent magnet couplings. Traditional bonded magnet preparation processes mainly include molding and injection molding. These methods form magnets with uniform internal magnetic powder distribution by uniformly mixing magnetic powders and binders and directly curing them. Currently, with the improvement of motor efficiency and the reduction of sensor size, a single uniform magnetic property can no longer meet the requirements of specific application scenarios. For example, if the magnetic ring of a motor rotor can form a magnetic property gradient with a high outer and low inner in the radial direction, the distribution of the air gap magnetic field can be optimized and eddy current losses can be reduced; similarly, if the magnetic core of a sensor has a magnetic permeability gradient, the sensitivity and linearity of the signal will be significantly improved. In the prior art, there are mainly two methods to achieve magnet gradient: the first is the segmented molding process, which fills materials with different magnetic powder ratios layer by layer and cures them, but this method has problems such as weak interfacial bonding force between layers, complex process, and low material utilization rate; the second is the post-processing method, which locally modifies a uniform magnet through mechanical processing or laser treatment. This method will damage the structural integrity of the magnet and increase production costs.

[0003] After inquiry, Patent CN115888940B mentions a method for regulating the remanence intensity between different positions of a bonded magnet, that is, by screening different magnetic powder particle sizes, making the magnetic powder particle sizes different in different parts of the magnetic ring, so as to achieve the purpose of regulating its magnetic field strength. Patent CN113764148B mentions a method for regulating the magnetic field strength at different positions of a bonded magnet by stacking and molding with different ratios / densities of magnetic powder content. Patent CN118299144A mentions achieving local strengthening of a ring magnet by using different types of magnets to press-fit the inner and outer layers of a bonded magnetic ring. The above several molding methods cannot avoid the limitations of segmented molding or local modification, that is, weak interfacial bonding force, complex process, and high production cost.

[0004] In view of this, a device and method for radial gradient magnetic powder distribution of bonded magnets with centrifugal-assisted curing are proposed, focusing on solving the molding problem of bonded magnets with radial magnetic powder gradient distribution. Summary of the Invention

[0005] In order to solve the deficiencies of the above technologies, the present invention provides a device and method for radial gradient magnetic powder distribution of bonded magnets with centrifugal-assisted curing.

[0006] To solve the above technical problems, the technical solution adopted by the present invention is: a device and method for radial gradient magnetic powder distribution of a centrifugal-assisted solidified bonded magnet, including,

[0007] A centrifugal barrel unit, as a slurry container, is subjected to centrifugal force to cause the magnetic powder to radially migrate in the binder. The centrifugal barrel unit includes a centrifugal barrel body and a first end cover and a second end cover respectively located at the open ends on both sides thereof. Rotating shafts are provided at the centers of the first end cover and the second end cover;

[0008] A transmission system, which is in transmission connection with the centrifugal barrel unit and drives its rotation, and the transmission system is also implemented in a manner of regulating the rotation speed of the centrifugal barrel unit;

[0009] A heating and curing device, which surrounds the outer circle of the centrifugal barrel unit, and a matching gap is formed between the heating and curing device and the centrifugal barrel body.

[0010] Further, the centrifugal barrel body is integral or split.

[0011] Further, a stepped inner layer with a smaller diameter is formed on the inner side surfaces of the first end cover and the second end cover. The maximum diameter of the inner layer matches the maximum diameter of the centrifugal barrel body, and a number of corresponding groups of threaded holes are provided on the outer ring parts of the inner layers of the first end cover and the second end cover respectively.

[0012] Further, the corresponding groups of threaded holes on the first end cover and the second end cover are jointly fastened with connecting rods, and several connecting rods are circumferentially and evenly distributed around the centrifugal barrel body.

[0013] Further, an air port and a feeding port communicating with the inner cavity of the centrifugal barrel are provided on the first end cover. An air port cover is detachably connected to the air port, and a feeding port cover is detachably connected to the feeding port.

[0014] Further, bearings are provided on the rotating shafts on both sides and are respectively rotationally connected and fastened to the shaft sleeves through the bearings.

[0015] Further, the transmission system includes a servo motor, and the servo motor is in transmission connection with one of the rotating shafts through a coupling.

[0016] A method for a device for radial gradient magnetic powder distribution of a centrifugal-assisted solidified bonded magnet includes the following steps:

[0017] S1. Premixing stage, mixing and stirring magnetic powder, silane coupling agent and binder to form a uniform slurry, and the binder is an epoxy resin and curing agent system;

[0018] S2. Assembly stage. First, select a split centrifugal barrel or an integral centrifugal barrel according to the magnet type. Second, spray a mold release agent on the inner wall of the centrifugal barrel. Third, complete the rigid connection of the centrifugal barrel unit. Finally, close the air port and the feeding port after feeding.

[0019] S3. Centrifugal gradient forming stage, including

[0020] The first sub-stage, with a time of 0 - 5 minutes, starts the servo motor to drive the rotation speed of the centrifugal barrel unit to increase from 0 to 1500 - 1800 rpm, causing the magnetic powder to migrate and concentrate towards the outer edge.

[0021] The second sub-stage, with a time of 5 - 15 minutes, steps down the rotation speed of the centrifugal barrel unit to 800 - 1000 rpm through the servo motor to promote the penetration of the resin into the gaps between the magnetic powder.

[0022] The third sub-stage, with a time from 15 minutes to the completion of curing, stabilizes the rotation speed of the centrifugal barrel unit at 500 rpm through the servo motor to maintain the distribution gradient structure generated by the magnetic powder before.

[0023] S4. Curing stage, including

[0024] Pre-curing, at the pre-curing temperature of the epoxy resin, increases the viscosity of the slurry.

[0025] Main curing, at the curing temperature of the epoxy resin, the magnetic powder surface-modified by the silane coupling agent reacts with the epoxy resin to maintain a solid state.

[0026] Post-curing, at a temperature lower than the curing temperature of the epoxy resin, releases the stress of the formed bonded magnet.

[0027] S5. Demolding stage. After cooling, disassemble the centrifugal barrel unit to take out the bonded magnet.

[0028] Furthermore, the particle size of the magnetic powder is 1 - 10 μm, and the addition content is 70 - 85 wt%.

[0029] The silane coupling agent is KH-550, and the addition content is 0.5 - 2 wt%.

[0030] Furthermore, the mixing and stirring speed in the premixing stage is 200 - 400 rpm, and the mixing and stirring time is 30 - 60 minutes.

[0031] Centrifugal-assisted curing bonded magnet radial gradient magnetic powder distribution device and method, by synergistically optimizing the centrifugal-based distribution and curing device and process parameters, realizes the integrated molding process of magnetic powder gradient distribution and epoxy resin curing. This process does not require gradient segmented molding or secondary processing molding, greatly improving the efficiency of the process flow. The prepared magnet has strong interfacial bonding force, high material density, and its magnetic properties can meet the special requirements of the device for the spatial magnetic field; in the dimension design of the centrifugal barrel, a split or integrated form can be flexibly adopted to adapt to the extraction of finished products in different scenarios; in the process method, by using centrifugal rotation assistance, the magnetic powder gathers on the outer circle of the magnet during the molding process, so as to achieve the effect that the magnetic induction intensity of the outer circle is higher than that of the inner circle. This optimized magnetic powder distribution structure enables the magnet to exhibit higher magnetic induction intensity under a limited magnet volume and magnetic powder content, meeting the usage requirements under various working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is the structural setup diagram of the present invention.

[0033] Figure 2 This is the structural setup diagram of the centrifugal barrel unit.

[0034] Figure 3 This is the comparison diagram between the integrated and split forms of the centrifugal barrel body.

[0035] In the figure: 1. Centrifugal barrel unit; 10. Centrifugal barrel body; 11. First end cover; 110. Inner layer; 12. Second end cover; 13. Connecting rod; 14. Threaded hole; 15. Air port; 16. Air port cover; 17. Feeding port; 18. Feeding port cover; 19. Rotating shaft

[0036] 2. Transmission system; 20. Servo motor; 21. Coupling; 22. Bearing; 23. Tightening bushing

[0037] 3. Heating and curing device. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0038] The present invention will be further described in detail below with reference to the drawings and specific embodiments.

[0039] Embodiment 1

[0040] This embodiment relates to a centrifugal-assisted curing bonded magnet radial gradient magnetic powder distribution device and method, which innovates in the structure of the centrifugal barrel. By adapting different forms of the centrifugal barrel to the scenarios of extracting finished products, on this basis, based on the inherent density difference between the magnetic powder and the binder, combined with the viscosity change during the curing process of the binder, the dynamic regulation of centrifugal force is combined with the resin curing process by using rotational conditions. Through the coordinated control of the rotational speed and temperature in stages, the directional migration and gradient curing of the magnetic powder are realized, achieving the effect of radial gradient distribution of the molded bonded magnet.

[0041] The device for radial gradient magnetic powder distribution of a centrifugal-assisted solidified bonded magnet includes a centrifugal barrel unit 1, which, as a slurry container, is subjected to centrifugal force to cause the magnetic powder to migrate radially in the binder. As Figure 2 shown, the centrifugal barrel unit 1 includes a centrifugal barrel body 10, a first end cover 11 and a second end cover 12 respectively located at the open ends on both sides thereof. Rotating shafts 19 are provided at the centers of the first end cover 11 and the second end cover 12.

[0042] Preferably, the centrifugal barrel body 10 adopts a cylindrical structure. In terms of material, metal materials such as stainless steel can be selected, and polymer composite materials such as carbon fiber composite materials can also be selected. Compared with traditional general-purpose containers, the structure of this embodiment is optimized for the requirements of magnet gradient forming. As Figure 3 shown, the centrifugal barrel body 10 includes an integral or split type. The integral centrifugal barrel body 10, such as that made of carbon fiber composite material, can directly serve as a rotor sheath to avoid damage to the gradient structure caused by secondary processing. The split centrifugal barrel body 10, as Figure 3 shown in the three-piece structure, is convenient for demolding and is suitable for scenarios where finished products such as magnetic rings need to be taken out.

[0043] As Figure 2 shown, both the first end cover 11 and the second end cover 12 are solid flange structures. An inner layer 11 with a smaller diameter in a stepped shape is formed on the inner side surfaces of the first end cover 11 and the second end cover 12. The maximum diameter of the inner layer 11 matches the maximum diameter of the centrifugal barrel body 10, thereby strengthening the sealing effect at the connection position. A number of corresponding groups of threaded holes 14 are provided on the outer ring parts of the inner layers 11 of the first end cover 11 and the second end cover 12 respectively, which is convenient for the positioning and rigid connection of the first end cover 11 and the second end cover 12.

[0044] Furthermore, the corresponding groups of threaded holes 14 on the first end cover 11 and the second end cover 12 are jointly fastened with a connecting rod 13. Then, several said connecting rods 13 are evenly distributed circumferentially around the centrifugal barrel body 10. Therefore, a ring-shaped frame type rigid connection is formed around the centrifugal barrel body 10, ensuring the structural strength. And the non-invasive design avoids occupying the internal space of the barrel body, ensuring no structural interference during slurry filling, and at the same time being convenient for disassembly, installation and maintenance. It goes without saying that external threads adapted to the threaded holes 14 are provided at both ends of the connecting rod 13.

[0045] An air port 15 and a feeding port 17 communicating with the inner cavity of the centrifugal barrel body 10 are provided on the first end cover 11 to ensure uniform slurry filling and no bubble interference. The number of the air port 15 and the feeding port 17 is not limited in this embodiment. It should be noted that in actual processing, in order to maintain the centrifugal dynamic balance, auxiliary holes of the same specification can be added at the centrosymmetric positions of the air port 15 and the feeding port 17 respectively. An air port cover 16 is detachably connected to the air port 15, and a feeding port cover 18 is detachably connected to the feeding port 17.

[0046] Bearings 22 are provided on both sides of the rotating shafts 19, and each is rotatably connected to the fastening bushing 23 through the bearing 22.

[0047] As Figure 1 shown, the transmission system 2 is drivingly connected to the centrifuge barrel unit 1 and drives its rotation. The transmission system 2 is also implemented in a manner of regulating the rotation speed of the centrifuge barrel unit 1. The transmission system 2 includes a servo motor 20. The servo motor 20 is drivingly connected to one of the rotating shafts 19 through a coupling 21, thus forming a tight driving connection relationship. Under the drive of the servo motor 20, the centrifuge barrel body 10 reaches the specified rotation speed. The servo motor 20 selected in this embodiment supports stepless speed regulation and multi-segment speed gradient programming, and further realizes the stepwise increase or decrease of the rotation speed of the centrifuge barrel body 10, which can be customized according to requirements.

[0048] The heating and curing device 3 surrounds the outer ring of the centrifuge barrel unit 1. The heating and curing device 3 provides a curing temperature field for the magnetic powder slurry inside the centrifuge barrel body 10 through external heating. A matching gap is formed between the heating and curing device 3 and the centrifuge barrel body 10. It should be noted that the heating mechanism adopted by the heating and curing device 3 is a closed cavity, and air-blast heating is used. The temperature control supports multi-segment temperature control programming and heating rate control.

[0049] The method of the centrifugal-assisted curing bonded magnet radial gradient magnetic powder distribution device in this embodiment is characterized by including the following steps:

[0050] S1. Premixing stage: Mix and stir magnetic powder, silane coupling agent and binder to form a uniform slurry. The binder is an epoxy resin and curing agent system;

[0051] Preferably, the particle size of the magnetic powder is 1 - 10 μm, and the added content is 70 - 85 wt%. The finer the particle size of the magnetic powder, the easier it is to migrate due to centrifugal rotation in the mixed slurry, and at the same time, it avoids the aggregation phenomenon of the magnetic powder in the epoxy resin; the silane coupling agent is KH-550, and the added content is 0.5 - 2 wt%. The silane coupling agent is used to improve the interfacial bonding, specifically chemically modify the surface of the magnetic powder, improve the bonding force between the magnetic powder and the epoxy resin, and effectively inhibit the interfacial peeling phenomenon of the magnetic powder under the action of high centrifugal force;

[0052] The mixing and stirring speed in the premixing stage is 200 - 400 rpm, and the mixing and stirring time is 30 - 60 minutes to make the slurry viscosity stable.

[0053] S2. Assembly stage: First, select a split centrifuge barrel body 10 or an integral centrifuge barrel body 10 according to the magnet type. Secondly, spray a release agent on the inner wall of the centrifuge barrel body 10. Thirdly, complete the rigid connection of the centrifuge barrel unit 1. Finally, close the air port 15 and the injection port 17 after injecting the material;

[0054] It should be noted that if the split centrifugal barrel 10 is adopted, it needs to be pre-assembled and joined together.

[0055] S3. Centrifugal gradient forming stage, including,

[0056] The first sub-stage, with a time of 0 - 5 minutes, starts the servo motor 20 to drive the rotational speed of the centrifugal barrel unit 1 to increase from 0 to 1500 - 1800 rpm. The strong centrifugal force generated at this rotational speed causes the magnetic powder to migrate and concentrate towards the outer edge;

[0057] The second sub-stage, with a time of 5 - 15 minutes, gradually reduces the rotational speed of the centrifugal barrel unit 1 to 800 - 1000 rpm through the servo motor 20, promoting the penetration of the resin into the gaps between the magnetic powders. Specifically, at this rotational speed, the sedimentation speed can be slowed down and the epoxy resin can be promoted to penetrate into the gaps between the magnetic powders, avoiding the phenomenon of decreased bonding force or even detachment due to too little epoxy resin content between the magnetic powders;

[0058] The third sub-stage, with a time from 15 minutes to the completion of curing, stabilizes the rotational speed of the centrifugal barrel unit 1 at 500 rpm through the servo motor 20, maintaining the distribution gradient structure of the magnetic powder generated previously. Specifically, at this rotational speed, the distribution gradient structure of the magnetic powder generated in the previous two stages can be maintained and the sedimentation phenomenon caused by the secondary flow of the magnetic powder due to gravity can be inhibited.

[0059] S4. Curing stage, including,

[0060] Pre-curing, at the pre-curing temperature of the epoxy resin, increases the viscosity of the slurry and delays the migration speed of the magnetic powder for subsequent curing;

[0061] Main curing, at the curing temperature of the epoxy resin, the magnetic powder surface-modified by the silane coupling agent reacts with the epoxy resin to maintain a solid state;

[0062] Post-curing, at a temperature lower than the curing temperature of the epoxy resin, releases the stress of the formed bonded magnet.

[0063] S5. Demolding stage, after cooling, disassembles the centrifugal barrel unit 1 to take out the bonded magnet.

[0064] The method of the centrifugal-assisted curing bonded magnet radial gradient magnetic powder distribution device disclosed in this embodiment is based on the collaborative optimization of device and process parameters, realizes the integrated molding of magnetic powder gradient distribution and epoxy resin curing, does not require gradient segmented molding or secondary processing molding, and has high process flow efficiency; the prepared magnet has strong interface bonding force, high material density, and magnetic properties that can meet the special requirements of the device for the spatial magnetic field.

[0065] Example 2

[0066] Based on Example 1, this example takes the preparation of a NdFeB magnetic ring with a radial distribution gradient of magnetic powder as an example.

[0067] First, assemble the split centrifugal barrel body 10 made of stainless steel, and then install the entire centrifugal barrel unit 1; after cleaning the inner wall of the centrifugal barrel body 10, evenly coat it with a release agent, and preheat it to 50 °C after completion.

[0068] Secondly, add 80% NdFeB magnetic powder, 9% epoxy resin, 9% curing agent and 2% silane coupling agent to an external mixer. The mixer first mixes at a low speed of 200 rpm for 5 minutes to wet the materials, and then raises the speed to 400 rpm for high-speed dispersion for 15 minutes and uses a vacuum pump to remove air bubbles; then transfer the mixed slurry to the barrel of a high-pressure injection machine and inject it into the centrifugal barrel body 10 from the injection port. After filling the centrifugal barrel body 10, close the injection port 17 and discharge the residual gas.

[0069] Thirdly, perform centrifugation:

[0070] Within the first 3 minutes, linearly increase the rotation speed of the centrifugal barrel body 10 from 0 to 1500 rpm, use the centrifugal acceleration to drive the magnetic powder to migrate outward to form a magnetic powder enrichment layer, and keep running at 1500 rpm for 5 minutes; then gradually reduce the speed and stabilize at 800 rpm at 10 minutes; after 15 minutes, reduce the speed to 500 rpm, and at the same time start the heating and curing device to heat the centrifugal barrel body 10.

[0071] It should be noted that the curing process is divided into pre-curing (keep warm at 60 °C for 30 minutes), main curing (keep warm at 100 - 120 °C for 1 hour) and post-curing (keep warm at 80 °C for 30 minutes).

[0072] Finally, wait for the centrifugal barrel body 10 to cool down and then remove it. Disassemble the centrifugal barrel body 10 to take out the bonded magnet, and then a magnetic ring with corresponding dimensions can be obtained through machining.

[0073] Thus, a bonded magnetic ring with the magnetic powder density increasing from the inside to the outside along the radial direction is obtained.

[0074] Example 3

[0075] Based on Example 1, this example takes the preparation of a high-speed motor composite rotor with a specific volume as an example. It should be noted that the specific volume is not an unclear concept, but rather the meaning of being produced according to actual needs in existing production and manufacturing.

[0076] First, install the integral centrifugal barrel 10 made of carbon fiber. The thin-walled centrifugal barrel 10 made of carbon fiber can be directly used as a rotor sheath in the subsequent process without taking out the formed rotor inside. After the installation of the centrifugal barrel unit 1 is completed, it is connected to the drive system 2. Then, the inner wall of the centrifugal barrel 10 is evenly coated with silane coupling agent after cleaning to enhance the bonding force between the formed composite rotor and the centrifugal barrel 10 used as a sheath. After completion, it is preheated to 50°C. It should be noted that since the centrifugal barrel 10 in this embodiment is directly used as a rotor sheath, there is no need to coat a release agent on the inner wall of the centrifugal barrel 10, but the silane coupling agent mentioned above.

[0077] Secondly, mix 50% NbFeB magnetic powder, 24% epoxy resin, 24% curing agent and 2% silane coupling agent in an external mixer at a speed of 500 rmp for 10 minutes to make them fully mixed, and use an external vacuum pump to remove the air bubbles therein.

[0078] Thirdly, helically wrap the carbon fiber tow around the surface of the metal shaft through a winding system to make a carbon fiber multi-layer pre-impregnated structure of corresponding size according to the required size. Subsequently, place the made carbon fiber multi-layer pre-impregnated structure in the thin-walled integral centrifugal barrel 10 made of carbon fiber, and inject the slurry made of magnetic powder and epoxy resin at the injection port 17.

[0079] After the slurry injection is completed, perform centrifugation:

[0080] Within the first 3 minutes, the rotation speed of the centrifugal barrel 10 linearly increases from 0 to 1800 rpm, and the centrifugal acceleration is used to drive the magnetic powder to migrate outwards to form a magnetic powder enrichment layer. Keep running at 1800 rpm for 5 minutes, and then gradually reduce the speed to stabilize at 1000 rpm at 10 minutes. After 15 minutes, the rotation speed is reduced to 500 rpm, and at the same time, start the curing program. Heat the centrifugal barrel device through the heating curing device 3. The curing process is divided into pre-curing (keep warm at 60°C for 30 minutes), main-curing (keep warm at 100 - 120°C for 1 hour) and post-curing (keep warm at 80°C for 30 minutes).

[0081] Finally, after the centrifugal barrel 10 cools down, disassemble the centrifugal barrel 10 to form a high-speed motor composite rotor with a high magnetic powder content in the outer layer, high fiber strength in the inner layer and an integrated carbon fiber rotor sheath.

[0082] The present application discloses a device and method for radial gradient magnetic powder distribution of a centrifugal-assisted solidified bonded magnet. By synergistically optimizing the centrifugal-based distribution and solidification device and process parameters, an integrated forming process of magnetic powder gradient distribution and epoxy resin solidification is achieved. This process does not require gradient segmented forming or secondary processing forming, greatly improving the efficiency of the process flow. The prepared magnet has strong interfacial bonding force, high material density, and its magnetic properties can meet the special requirements of the device for the space magnetic field. In the dimension design of the centrifugal barrel, a split or integrated form can be flexibly adopted to adapt to the extraction of finished products in different scenarios. In terms of the process method, by using centrifugal rotation assistance, the magnetic powder aggregates on the outer circle of the magnet during the forming process, thus achieving the effect that the magnetic induction intensity of the outer circle is higher than that of the inner circle. This optimized magnetic powder distribution structure enables the magnet to exhibit a higher magnetic induction intensity under a limited magnet volume and magnetic powder content, meeting the usage requirements under various working conditions.

[0083] The above embodiments are not limitations on the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions, or substitutions made by those skilled in the art within the scope of the technical solution of the present invention also fall within the protection scope of the present invention.

Claims

1. A radial gradient magnetic powder distribution device for bonded magnets with centrifugal assisted curing, characterized in that: include, A centrifugal barrel unit (1) is used as a slurry container to cause magnetic powder to migrate radially in a binder under the action of centrifugal force. The centrifugal barrel unit (1) comprises a centrifugal barrel body (10) and a first end cover (11) and a second end cover (12) respectively located at two open sides thereof. The first end cover (11) and the second end cover (12) are both provided with a rotating shaft (19) at their axes. A transmission system (2) is connected to the centrifugal bucket unit (1) and drives the centrifugal bucket unit (1) to rotate. The transmission system (2) is also implemented in a manner of regulating the rotation speed of the centrifugal bucket unit (1); The heating and curing device (3) surrounds the outer ring of the centrifugal barrel unit (1), and a matching gap is formed between the heating and curing device (3) and the centrifugal barrel body (10).

2. The centrifugal assisted solidification bonded magnet radial gradient magnetic powder distribution device according to claim 1, characterized in that: The centrifugal barrel body (10) is of an integrated type or a split type.

3. The centrifugal assisted solidification bonded magnet radial gradient magnetic powder distribution device according to claim 1, characterized in that: The inner side surfaces of the first end cover (11) and the second end cover (12) are both formed with a circle of stepped inner layer (11) with a smaller diameter, the maximum diameter of the inner layer (11) matches the maximum diameter of the centrifugal barrel (10), and the outer circle portion of the inner layer (11) of each of the first end cover (11) and the second end cover (12) is provided with a plurality of threaded holes (14) in corresponding groups.

4. The radial gradient magnetic powder distribution device for centrifugal assisted solidification bonded magnet according to claim 3, characterized in that: The threaded holes (14) in the first end cover (11) and the second end cover (12) are correspondingly grouped together to fasten a connecting rod (13), and a plurality of the connecting rods (13) are evenly distributed in the circumferential direction of the outer periphery of the centrifugal barrel body (10).

5. The centrifugal assisted solidification bonded magnet radial gradient magnetic powder distribution device according to claim 1, characterized in that: The first end cover (11) is provided with an air port (15) and a material injection port (17) which are connected to the inner cavity of the centrifugal barrel body (10); the air port (15) is detachably connected to an air port cover (16), and the material injection port (17) is detachably connected to an injection port cover (18).

6. The centrifugal assisted solidification bonded magnet radial gradient magnetic powder distribution device according to claim 1, characterized in that: The rotating shafts (19) on both sides are provided with bearings (22) and are rotatably connected to the fastening sleeves (23) through the bearings (22).

7. The centrifugal assisted solidification bonded magnet radial gradient magnetic powder distribution device according to claim 1, characterized in that: The transmission system (2) comprises a servo motor (20), and the servo motor (20) is transmission-connected to one side of the rotating shaft (19) via a coupling (21).

8. The method of the centrifugal assisted solidification bonded magnet radial gradient magnetic powder distribution device according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1. In the premixing stage, the magnetic powder, the silane coupling agent and the binder are mixed and stirred to form a uniform slurry, wherein the binder is an epoxy resin and a curing agent system; S2. Assembly stage, firstly, according to the type of magnet, a split centrifugal barrel (10) or an integrated centrifugal barrel (10) is selected, and then a release agent is sprayed on the inner wall of the centrifugal barrel (10), and then the rigid connection of the centrifugal barrel unit (1) is completed, and finally, the air port (15) and the injection port (17) are closed after injection; S3. Centrifugal gradient forming stage, including: In the first sub-stage, the duration is 0-5 minutes, the servo motor (20) is started to drive the rotation speed of the centrifugal bucket unit (1) from 0 to 1500-1800 rpm, so that the magnetic powder migrates to the outer edge for enrichment; In the second sub-stage, which lasts for 5-15 minutes, the rotation speed of the centrifugal barrel unit (1) is reduced stepwise to 800-1000 rpm by the servo motor (20) to promote the penetration of the resin into the gaps between the magnetic powders; The third sub-stage lasts for 15 minutes until the curing is completed, and the rotation speed of the centrifugal barrel unit (1) is stabilized at 500 rpm by the servo motor (20) to maintain the distribution gradient structure of the magnetic powder previously generated; S4. Curing stage, including, Pre-curing, at the pre-curing temperature of the epoxy resin, to increase the viscosity of the slurry; Main curing: at the curing temperature of epoxy resin, the magnetic powder surface modified by silane coupling agent undergoes a cross-linking reaction with epoxy resin to maintain a solid state; Post-curing, at a temperature lower than the curing temperature of the epoxy resin, to release the stress of the molded bonded magnet; S5. Demolding stage: after cooling, the centrifugal barrel unit (1) is disassembled to take out the bonded magnet.

9. The method of the centrifugal assisted solidification bonded magnet radial gradient magnetic powder distribution device according to claim 8, characterized in that: The particle size of the magnetic powder is 1-10 μm, and the added content is 70-85 wt%; The silane coupling agent is KH-550, and the added content is 0.5-2wt%.

10. The method of the centrifugal assisted solidification bonded magnet radial gradient magnetic powder distribution device according to claim 8, characterized in that: The mixing and stirring speed in the premixing stage is 200-400 rpm, and the mixing and stirring time is 30-60 minutes.

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