Shielding device for a strong magnetic source

Abstract

The embodiment of the application provides a shielding device of a strong magnetic source, which comprises an outer layer, an intermediate layer, an inner layer and an insulation layer; the outer layer is made of silicon steel sheet or amorphous alloy, is used for absorbing a low-frequency magnetic field and preventing material saturation; the intermediate layer is an orthogonal laminated electromagnetic shielding net, is used for enhancing low-frequency magnetic flux absorption, high-frequency eddy current dissipation and demagnetization excitation; the inner layer is made of permalloy and permanent magnet material, is used for absorbing a high-frequency magnetic field and providing a high-frequency magnetic permeability path; and the insulation layer is a polyimide film or a ceramic coating, is arranged between the outer layer and the inner layer, and is used for insulating the outer layer and the inner layer. The application solves the deficiencies of related technologies in wide-band compatibility, structural flexibility and secondary interference suppression, and has high efficiency, safety and economy.

Description

Technical Field

[0001] This application relates to the field of electromagnetic shielding technology, and in particular to a shielding device for a strong magnetic source. Background Technology

[0002] In related technologies, active shielding systems are used in some applications to avoid electromagnetic interference. Specifically, active shielding systems use an electric current to generate a reverse magnetic field to counteract the interfering magnetic field. Therefore, it is evident that active shielding systems consume a lot of power, have high power consumption, generate significant heat over long periods, have poor battery life, and are costly.

[0003] To address the aforementioned issues, researchers have proposed using passive soft magnetic materials for shielding. Passive shielding relies on the material's magnetic attraction, conduction, and eddy current dissipation; therefore, it requires no power, achieving zero energy consumption and is more energy-efficient than active shielding systems. Permalloy and other similar materials can be used as passive soft magnetic materials.

[0004] However, permalloy alone is prone to magnetic saturation under strong magnetic fields. For example, in a 1.5T magnetic field, the shielding magnetic efficiency of a 2mm thick permalloy will decrease by 40%. Therefore, permalloy alone is not suitable for wide-band magnetic shielding applications. Summary of the Invention

[0005] This application provides a shielding device for a strong magnetic source, which can be used to make the shielding device applicable to wide-band magnetic shielding scenarios.

[0006] This application provides a shielding device for a strong magnetic source, the shielding device comprising an outer layer, a middle layer, an inner layer, and an insulating layer; The outer layer is made of silicon steel sheet or amorphous alloy and is used to absorb low-frequency magnetic fields and prevent material saturation. The intermediate layer is an orthogonal stacked electromagnetic shielding mesh, used to enhance low-frequency magnetic flux absorption, high-frequency eddy current dissipation, and demagnetization excitation; The inner layer is made of permalloy and permanent magnet material, and is used to absorb high-frequency magnetic fields and provide a high-frequency magnetic permeability path. The insulating layer is a polyimide film or a ceramic coating, sandwiched between the outer layer and the inner layer, for insulating the outer layer and the inner layer.

[0007] Optionally, one side of the inner layer is provided with a magnetic field convergence area, which is a pointed or conical structure; the other side of the inner layer is provided with a magnetic field weakening area, which is a U-shaped or ring-shaped structure, and the magnetic permeability of the material used in the magnetic field convergence area is higher than that of the material used in the magnetic field weakening area.

[0008] Optionally, the magnetic field convergence region is made of permalloy, and the magnetic field weakening region is made of the same material as the intermediate layer.

[0009] Optionally, the inner layer is provided with a fractal magnetic channel, which is made of permalloy.

[0010] Optionally, the permanent magnet material in the inner layer is a local strong magnet module, which is arranged in a fractal iteration manner and is arranged in an alternating N-S pattern.

[0011] Optionally, the fractal iteration arrangement of the local strong magnet module is matched with the fractal structure of the inner magnetic channel.

[0012] Optionally, the magnet of the local strong magnet module is a neodymium iron boron or samarium cobalt permanent magnet; the magnetic poles of the magnet of the local strong magnet module are arranged in a fractal iteration manner, and form a multi-level magnetic field gradient.

[0013] Optionally, the shielding device further includes a modular strong magnetic array; the modular strong magnetic array is a single-sided strong magnetic field structure, and the single-sided strong magnetic field structure is a honeycomb or hexagonal module; the modular strong magnetic array is attached to the outer side of the outer layer; the modular strong magnetic array includes a converging side and a weakening side, the converging side facing the external interference source, and the weakening side facing the protected equipment.

[0014] Optionally, the honeycomb array units are bonded together with polyimide tape, and multiple array units are connected by magnetic snap-fit ​​magnets.

[0015] Optionally, the outer layer is made of a material produced by rapid quenching and dehydrogenation annealing; and / or, The outer layer is made of a material produced by cold rolling and dehydrogenation annealing.

[0016] Optionally, the orthogonal stacked electromagnetic shielding mesh of the intermediate layer is an orthogonal stacked coil mesh made of copper.

[0017] Optionally, the permalloy internal magnetic domains of the inner layer are arranged in an orderly manner along a preset direction by pre-treatment with an external magnetic field.

[0018] Optionally, the insulating layer is a polyimide film or a ceramic coating, and the dielectric constant ε of the insulating layer is ≥10.

[0019] Optionally, the surface of the shielding device is further provided with a heat dissipation layer, which includes micro heat dissipation fins or liquid cooling pipes; the micro heat dissipation fins are made of aluminum alloy; the liquid cooling pipes are copper pipes, and the cooling medium inside the liquid cooling pipes is deionized water.

[0020] Optionally, a gradient permeability transition layer is provided between the outer layer and the intermediate layer, and / or a gradient permeability transition layer is provided between the intermediate layer and the inner layer; The gradient permeability transition layer is composed of magnetic powder-polymer composite material or multilayer nanocrystalline ribbon stack, and its permeability is gradient distributed along the thickness direction of the shielding device. It is used to reduce magnetic flux reflection loss caused by abrupt changes in permeability between the outer layer and the middle layer, and / or between the middle layer and the inner layer.

[0021] The shielding device using the strong magnetic source disclosed in this application achieves unilateral strong magnetic field generation and directional shielding through a refined magnetic circuit design based on fractal structure and a strong magnetic array layout without magnetic moment, significantly improving shielding effectiveness. Furthermore, the modular magnetic array attachment design adapts to complex geometric structures, reducing installation difficulty and cost. In addition, by adding a gradient permeability transition layer, the magnetic flux coupling efficiency between multi-layer structures is optimized, further reducing eddy current losses and interface reflection losses. Finally, by combining high-permeability materials (such as permalloy) with magnetic domain directional alignment technology, eddy current losses are effectively reduced and thermal stability is enhanced, overcoming the shortcomings of related technologies in terms of wideband compatibility, structural flexibility, and secondary interference suppression. This application is applicable to high-precision equipment (such as aerospace instruments and magnetic resonance imaging) and industrial scenarios (such as motors and communication equipment), combining high efficiency, safety, and economy. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 A schematic diagram of the structure of a shielding device for a strong magnetic source provided in an embodiment of this application; Figure 2 A schematic diagram illustrating a scenario where a local strong magnet module achieves mutual cancellation of overall magnetic moments, as provided in an embodiment of this application. Figure 3 A schematic diagram of the structure of another shielding device for a strong magnetic source provided in an embodiment of this application; Figure 4 This is a cross-sectional schematic diagram of a shielding device for a fractal geometry strong magnetic source provided in an embodiment of this application.

[0024] Explanation of reference numerals in the attached figures: 1-Outer layer; 2-Insulating layer; 3-Inner layer; 4-Heat dissipation layer; 5-Intermediate layer; 7-Local strong magnet module. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0026] This application provides a shielding device for a strong magnetic source, such as... Figure 1 As shown, the shielding device may include an outer layer 1, a middle layer 5, an inner layer 3, and an insulating layer 2. The outer layer 1 is made of silicon steel sheet or amorphous alloy and is used to absorb low-frequency magnetic fields and prevent material saturation. The middle layer 5 is an orthogonal multilayer electromagnetic shielding mesh used to enhance low-frequency magnetic flux absorption, high-frequency eddy current dissipation, and demagnetization excitation. The inner layer 3 is made of permalloy and permanent magnet material and is used to absorb high-frequency magnetic fields and provide a high-frequency permeability path. The insulating layer 2 is a polyimide film or ceramic coating sandwiched between the outer layer 1 and the inner layer 3 to insulate both layers.

[0027] The shielding device consists of the following layers from the outside to the inside: outer layer 1, insulation layer 2, middle layer 5, and inner layer 3.

[0028] Based on the above structure, the embodiments of this application have carried out directional optimization design of the magnetic circuit, which may include: 1. Magnetic Conducting Channels in Fractal Structures: High-permeability alloys (such as permalloy) are used to guide magnetic lines of force to flow along a predetermined path, forming a closed magnetic circuit.

[0029] II. Asymmetric flux guiding design: A magnetic field convergence area (such as a pointed or conical structure) is set on one side of the magnet, and a magnetic field weakening area (such as a U-shaped or ring structure) is set on the other side. The magnetic flux is concentrated by a high permeability material and diffused by a low permeability material.

[0030] 3. Fractal Iterative Arrangement Design: Local strong magnet modules are arranged alternately in N-S order. The magnetic field strength is gradually changed by the mutual cancellation of the overall magnetic moments, but high magnetic flux density is retained in local areas.

[0031] IV. Modular Strong Magnetic Array Attachment Design: The single-sided strong magnetic field structure is made into a honeycomb or hexagonal module and attached to the outside of the strong magnetic component, with the converging side facing the external interference source and the weakening side facing the protected equipment.

[0032] The frequency of the low-frequency magnetic field can generally be from 0Hz (DC / static magnetic field) to 100kHz, while the frequency of the high-frequency magnetic field can generally be from 100kHz to 300GHz. This application does not limit the specific frequencies of the low-frequency and high-frequency fields.

[0033] Optionally, a magnetic field convergence area is provided on one side of the inner layer 3, which is a pointed or conical structure; a magnetic field weakening area is provided on the other side of the inner layer 3, which is a U-shaped or ring-shaped structure, and the magnetic permeability of the material used in the magnetic field convergence area is higher than that of the material used in the magnetic field weakening area.

[0034] Optionally, the material used in the magnetic field convergence zone is permalloy, and the material used in the magnetic field weakening zone is the same as that used in the intermediate layer 5.

[0035] Optionally, the inner layer 3 is provided with a fractal magnetic channel, which is made of permalloy.

[0036] Among them, permalloy is a soft magnetic material with extremely high magnetic permeability, which can greatly guide, converge and amplify magnetic fields, allowing the originally divergent magnetic field lines to be concentrated in the area where they need to work, thereby significantly enhancing the magnetic field gradient in that area.

[0037] Fractals are a type of "self-similar" geometric structure (i.e., the whole and its parts are similar). Designing the magnetic channel as a fractal means that the magnetic channel can achieve extremely complex magnetic field guidance and distribution within a limited space, enabling the creation of uniform magnetic fields or specific focusing effects at multiple scales.

[0038] Optionally, such as Figure 2 As shown, the permanent magnet material in the inner layer 3 is a local strong magnet module 7, which is arranged in a fractal iteration manner and is arranged in an alternating N-S pattern.

[0039] Among them, strong magnets can be interpreted as magnets made of rare-earth permanent magnet materials, such as neodymium iron boron (NdFeB) or samarium cobalt (SmCo). The remanence can reach 1.0 to 1.4 Tesla or higher.

[0040] The local strong magnet modules 7 are arranged alternately in a north-south-north-south-north-south-north pole sequence. This arrangement creates a strong magnetic field gradient in the central region, generating sufficient magnetic force to capture or deflect tiny particles (such as cells or magnetic beads). Furthermore, the placement of the local strong magnet modules 7 follows fractal principles; therefore, their layout is not a simple straight line or grid, but rather a nested arrangement according to certain mathematical rules. This design ensures efficient magnetic field transmission at both the macroscopic and microscopic levels.

[0041] Optionally, the fractal iteration arrangement of the local strong magnet module 7 is matched with the fractal structure of the magnetic channel of the inner layer 3.

[0042] In practical applications, the placement of the local strong magnet module 7 and the orientation of the magnetic conductive channel in the inner layer 3 correspond one-to-one. This one-to-one matching relationship enables the local strong magnet module 7 and the magnetic conductive channel in the inner layer 3 to form a highly coordinated customized coupling system in spatial geometry.

[0043] Specifically, the local strong magnet module 7, which serves as the power source, is not randomly arranged, but rather laid out according to a specific fractal iteration law and alternating N and S polarities. The magnetically conductive channels, made of high-permeability permalloy, have a complex fractal orientation designed in reverse based on the distribution characteristics of the magnetic source. When the two are precisely aligned, the magnetically conductive channels of the inner layer 3 can seamlessly receive the complex magnetic field generated by the local strong magnet module 7, guiding the magnetic field lines to flow and converge efficiently and with low loss along the preset fractal trajectory.

[0044] This structural matching not only fundamentally avoids unnecessary leakage and mutual cancellation of the magnetic field during transmission, but also maximizes the spatial utilization of fractal geometry and the magnetic permeability of permalloy, thereby maximizing the magnetic field gradient and focusing efficiency within an extremely limited microscopic space.

[0045] Optionally, the magnet of the local strong magnet module 7 is a neodymium iron boron or samarium cobalt permanent magnet; the magnetic poles of the magnet of the local strong magnet module 7 are arranged in a fractal iteration manner and form a multi-level magnetic field gradient.

[0046] Optionally, the shielding device further includes a modular strong magnetic array; the modular strong magnetic array is a single-sided strong magnetic field structure, which is a honeycomb or hexagonal module; the modular strong magnetic array is attached to the outside of the outer layer 1; the modular strong magnetic array includes a converging side and a weakening side, with the converging side facing the external interference source and the weakening side facing the protected equipment.

[0047] Optionally, the honeycomb array units are bonded together with polyimide tape, and multiple array units are connected by magnetic snap-fit ​​magnets.

[0048] Optionally, the material used for the outer layer 1 is made by quenching and dehydrogenation annealing; and / or, the material used for the outer layer 1 is made by cold rolling and dehydrogenation annealing.

[0049] Optionally, the orthogonal stacked electromagnetic shielding mesh of the intermediate layer 5 is an orthogonal stacked coil mesh made of copper.

[0050] Optionally, the permalloy internal magnetic domains of the inner layer 3 are arranged in an orderly manner along a preset direction by pre-treatment with an external magnetic field.

[0051] Understandably, before pretreatment, permalloy is not a single, unified magnet at the microscopic level, but rather composed of countless tiny magnetic domains. In its natural state, the magnetic fields of these countless tiny magnetic domains are randomly oriented, and their magnetism cancels each other out, resulting in a macroscopic absence of magnetism.

[0052] During the manufacturing or heat treatment (such as annealing) stages of permalloy production, a strong magnetic field in a specific direction can be applied externally. The purpose of this external strong magnetic field is to align the magnetic fields of the countless originally chaotic tiny magnetic domains within the material in an orderly manner along a predetermined direction.

[0053] Optionally, the insulating layer 2 is a polyimide film or a ceramic coating, and the dielectric constant ε of the insulating layer 2 is ≥10.

[0054] Optionally, such as Figure 3 As shown, the surface of the shielding device is also provided with a heat dissipation layer 4, which includes micro heat dissipation fins or liquid cooling pipes; the micro heat dissipation fins are made of aluminum alloy; the liquid cooling pipes are copper pipes, and the cooling medium inside the liquid cooling pipes is deionized water.

[0055] Optionally, a gradient permeability transition layer is provided between the outer layer 1 and the middle layer 5, and / or a gradient permeability transition layer is provided between the middle layer 5 and the inner layer 3; the gradient permeability transition layer is composed of magnetic powder-polymer composite material or multilayer nanocrystalline ribbon stack, and its permeability is distributed in a gradient along the thickness direction of the shielding device, which is used to reduce magnetic flux reflection loss caused by the sudden change in permeability between the outer layer 1 and the middle layer 5, and / or between the middle layer 5 and the inner layer 3.

[0056] This application provides two schemes for constructing gradient permeability transition layers: The first approach uses a magnetic powder-polymer composite material to construct a gradient permeability transition layer. This approach mixes soft magnetic metal powder with an insulating polymer matrix, and by precisely controlling the filling ratio and density of the magnetic powder at different spatial locations, a continuous and smooth transition of the material's macroscopic permeability is achieved. Due to the excellent insulating properties of the polymer matrix, this composite material can effectively cut off high-frequency eddy current paths, significantly reducing high-frequency losses. It also possesses excellent molding and processing capabilities, making it ideal for manufacturing transition layers with complex, irregular geometries.

[0057] For example, the following method can be used to prepare the magnetic powder-polymer composite gradient layer scheme: the matrix material is selected from thermosetting resin or thermoplastic polymer with high temperature resistance and high insulation performance, the magnetic filler is selected from soft magnetic alloy powder with a particle size controlled between 5 and 50 μm, the eddy current loss is reduced by surface insulation coating treatment, and the mass fraction of magnetic filler is gradually increased from 10% to 70% along the thickness direction by using multi-layer overlay or layer-by-layer spraying process.

[0058] The second approach utilizes a multilayer nanocrystalline ribbon stack structure to achieve a gradient permeability transition layer. This approach is constructed by stacking multiple extremely thin nanocrystalline alloy ribbons and, by changing the geometric cross-sectional area of ​​the stack, adjusting the combination order of ribbons with different magnetic properties, or altering the thickness of the magnetic fragmentation unit and the insulating coating layer, a gradient change in permeability is macroscopically equivalent. Thanks to the extremely high permeability and saturation magnetic flux density of the nanocrystalline material itself, combined with the effective suppression of eddy currents by interlayer insulation, this approach demonstrates superior overall performance in applications requiring strong magnetic field guidance and efficient electromagnetic shielding.

[0059] For example, the following method can be used to prepare a multilayer nanocrystalline ribbon stacking scheme: iron-based nanocrystalline ribbons are selected as the material, and the nanocrystalline ribbons are alternately stacked with insulating dielectric films. By controlling the number of stacks and the width and porosity of each layer, a structure in which the equivalent magnetic permeability is distributed in a stepped manner along the thickness direction is constructed.

[0060] Transition layer structure and location design: According to the overall magnetic circuit layout of the shielding device, gradient permeability transition layers are set at one or more locations. The layer between the outer layer 1 and the middle layer 5 is used to alleviate the permeability jump between the copper mesh (non-magnetic) of the outer layer 1 and the middle layer 5, and to reduce the reflection and scattering of magnetic flux when it enters the non-magnetic region from the high permeability material. The layer between the middle layer 5 and the inner layer 3 is used to smooth the permeability jump between the middle layer 5 (non-magnetic or low permeability) and the permalloy permanent magnet of the inner layer 3, and to improve the magnetic flux coupling efficiency.

[0061] In another embodiment of this application, a method for fabricating a shielding device for a strong magnetic source is provided. In this method, an outer layer 1, a middle layer 5, an inner layer 3, and an insulating layer 2 can be fabricated separately. For the outer layer 1, silicon steel sheets can be selected as the material. Silicon steel sheets have the following characteristics: high magnetic permeability, strong anti-saturation ability, and suitability for a 1T strong magnetic field environment. For the middle layer 5, the structure can adopt an orthogonal stacked electromagnetic shielding mesh design. Specifically, a copper mesh can be used, which has the following characteristics: provides high-frequency eddy current dissipation and can be connected to a demagnetizing excitation power supply. For the inner layer 3, permalloy and permanent magnets can be selected as the materials, processed through cold rolling and directional magnetic domain alignment processes (external magnetic field pretreatment). The external magnetic field pretreatment, i.e., the directional magnetic domain alignment process, allows the magnetic domains inside the permanent magnet material to be arranged in an orderly manner along a specific direction, forming a closed magnetic circuit, and designing a multi-level magnetic flux closed loop inside the shielding device. For the insulating layer 2, polyimide film or ceramic coating (dielectric constant ε≥10) can be selected as the material. Additionally, a heat dissipation layer 4 (optional design) can be added. Heat dissipation layer 4 can be constructed by setting micro-heat dissipation fins or liquid cooling pipes on the surface of the shielding layer. The fins of heat dissipation layer 4 can be made of aluminum alloy, the liquid cooling pipes can be made of copper, and the cooling medium can be deionized water.

[0062] In another embodiment of this application, a scheme for magnetic circuit orientation optimization design and assembly is provided. For example... Figure 4 As shown, in this scheme, the fractal magnetic channel design can employ a fractal geometric structure to design the magnetic channel, using permalloy as the magnetic material. The multi-level flux guiding design can adopt a converging side structure: designing a sharp-angled or conical flux converging region, concentrating the flux through a high-permeability alloy (such as permalloy); and a weakening side structure: designing a U-shaped or ring-shaped flux weakening region, diffusing the flux through copper or air gaps. Magnetic circuit calibration can be achieved through magnetic pole direction marking: laser micro / nano structure markings are engraved on the edges of the cellular module to ensure magnetic circuit alignment error ≤ ±5°. The local strong magnetic layout can be designed using a fractal iterative arrangement, arranging the local strong magnet modules 7 alternately in a N-S pattern, achieving a gradual change in magnetic field strength through mutual cancellation of the overall magnetic moments, while retaining high flux density in local areas. The array units can use neodymium iron boron or samarium cobalt permanent magnets, which can be combined using a modular attachment mounting method. Fabrication of magnetic array module: honeycomb unit: side length 15mm, thickness 3mm; magnetic buckle: integrated magnet (surface magnetic field strength not less than 0.3T), attached to the surface of strong magnetic component.

[0063] Finally, a set of experimental data is provided to demonstrate the performance of the shielding device provided in this application. Test methods: Static magnetic field: The magnetic field strength before and after shielding is measured using a magnetometer; Dynamic magnetic field: Signal attenuation before and after shielding is measured using a spectrum analyzer. Directional shielding verification: Converging side attenuation: External magnetic field attenuation rate ≥90% (by magnetic flux density comparison); Weakening side reduction: Internal magnetic field strength reduction ≥80% (by magnetic field distribution scanning). Thermal stability verification: Temperature control test: Within the range of -40℃ to 85℃, the surface temperature change of the shield is monitored using an infrared thermal imager, with performance fluctuation <5%.

[0064] In summary, this application can improve shielding effectiveness: it can effectively shield static magnetic fields of not less than 1T; it can improve magnetic flux transmission efficiency: the gradient permeability transition layer effectively reduces interlayer magnetic flux reflection, increasing magnetic flux transmission efficiency to over 90%, further enhancing the overall effectiveness of the shielding system under high field strength; it can reduce device weight: by optimizing the structure to replace the traditional dense magnet arrangement, the amount of magnets used is reduced; it can provide multi-layer shielding functionality: the magnet modules are arranged in a fractal iteration manner to form a multi-layer magnetic field gradient; the magnetic moment-free design avoids secondary interference, making it suitable for high-precision equipment (such as aerospace equipment, magnetic resonance imaging, etc.); it can improve structural flexibility: by utilizing the self-similarity of fractals to achieve gradual changes in magnetic field strength, the fractal array layout adapts to strong magnetic components with complex geometries; and it can improve temperature stability: performance fluctuation is <5% in the range of -40℃ to 85℃.

[0065] This application discloses a shielding device for a strong magnetic source. This device achieves unilateral strong magnetic field generation and directional shielding through a refined magnetic circuit design based on fractal structures and a strong magnetic array layout without magnetic moment, significantly improving shielding effectiveness. Furthermore, the modular magnetic array attachment design adapts to complex geometric structures, reducing installation difficulty and cost. In addition, by adding a gradient permeability transition layer, the magnetic flux coupling efficiency between multi-layer structures is optimized, further reducing eddy current losses and interface reflection losses. Finally, by combining high-permeability materials (such as permalloy) with magnetic domain directional alignment technology, eddy current losses are effectively reduced and thermal stability is enhanced. This addresses the shortcomings of related technologies in terms of wideband compatibility, structural flexibility, and secondary interference suppression. This application is applicable to high-precision equipment (such as aerospace instruments and magnetic resonance imaging) and industrial scenarios (such as motors and communication equipment), combining high efficiency, safety, and economy.

[0066] Although this application has been disclosed above with reference to preferred embodiments, it is not intended to limit this application. Any person skilled in the art can make possible changes and modifications to the technical solutions of this application by utilizing the methods and techniques disclosed above without departing from the spirit and scope of this application. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of this application without departing from the content of the technical solutions of this application shall fall within the protection scope of the technical solutions of this application.

[0067] The contents not described in detail in this application specification are common knowledge to those skilled in the art.

Claims

1. A shielding device for a strong magnetic source, characterized in that, The shielding device includes an outer layer, a middle layer, an inner layer, and an insulating layer; The outer layer is made of silicon steel sheet or amorphous alloy and is used to absorb low-frequency magnetic fields and prevent material saturation. The intermediate layer is an orthogonal stacked electromagnetic shielding mesh, used to enhance low-frequency magnetic flux absorption, high-frequency eddy current dissipation, and demagnetization excitation; The inner layer is made of permalloy and permanent magnet material, and is used to absorb high-frequency magnetic fields and provide a high-frequency magnetic permeability path. The insulating layer is a polyimide film or a ceramic coating, sandwiched between the outer layer and the inner layer, for insulating the outer layer and the inner layer.

2. The shielding device according to claim 1, characterized in that, One side of the inner layer is provided with a magnetic field convergence area, which is a pointed or conical structure; the other side of the inner layer is provided with a magnetic field weakening area, which is a U-shaped or ring-shaped structure. The magnetic permeability of the material used in the magnetic field convergence area is higher than that of the material used in the magnetic field weakening area.

3. The shielding device according to claim 2, characterized in that, The magnetic field convergence zone is made of permalloy, and the magnetic field weakening zone is made of the same material as the intermediate layer.

4. The shielding device according to claim 1, characterized in that, The inner layer has a fractal magnetic channel, which is made of permalloy.

5. The shielding device according to claim 4, characterized in that, The permanent magnet material in the inner layer is a local strong magnet module, which is arranged in a fractal iteration manner and is arranged in an alternating N-S pattern.

6. The shielding device according to claim 5, characterized in that, The fractal iterative arrangement of the local strong magnet module matches the fractal structure of the inner magnetic channel.

7. The shielding device according to claim 5, characterized in that, The magnets of the local strong magnet module are neodymium iron boron or samarium cobalt permanent magnets; the magnetic poles of the magnets of the local strong magnet module are arranged in a fractal iterative manner, forming a multi-level magnetic field gradient.

8. The shielding device according to claim 1, characterized in that, The shielding device further includes a modular strong magnetic array; the modular strong magnetic array is a single-sided strong magnetic field structure, and the single-sided strong magnetic field structure is a honeycomb or hexagonal module; the modular strong magnetic array is attached to the outer side of the outer layer; the modular strong magnetic array includes a converging side and a weakening side, the converging side faces the external interference source, and the weakening side faces the protected equipment.

9. The shielding device according to claim 8, characterized in that, The honeycomb array units are bonded together with polyimide tape, and multiple array units are connected by magnetic snap-fit ​​magnets.

10. The shielding device according to claim 1, characterized in that, A gradient permeability transition layer is provided between the outer layer and the middle layer, and / or a gradient permeability transition layer is provided between the middle layer and the inner layer; The gradient permeability transition layer is composed of magnetic powder-polymer composite material or multilayer nanocrystalline ribbon stack, and its permeability is gradient distributed along the thickness direction of the shielding device. It is used to reduce magnetic flux reflection loss caused by the sudden change in permeability between the outer layer and the middle layer, and / or to reduce magnetic flux reflection loss caused by the sudden change in permeability between the middle layer and the inner layer.

Images