Low-frequency magnetic field shielding method

Abstract

The invention provides a low-frequency magnetic field shielding method. The method comprises the following steps: carrying out three-direction adjustable design on a supporting framework of a magnetic shielding device; high-permeability materials are stacked according to a dumbbell-shaped mode, and the stacking size and interval of the high-permeability materials meet a specific mathematical relationship; a magnetic field shielding space of low-frequency noise is formed in a set area by adjusting the framework in three directions and arranging the high-magnetic-conductivity materials in a stacked mode. Through the design of the adjustable support framework, the framework can be adjusted in three directions according to the environment magnetic field and interference magnetic field state of the magnetic shielding device, so that the shielding device can realize a near-zero magnetic environment in a set area, and the shielding effectiveness on a low-frequency magnetic field is improved.

Description

Technical Field

[0001] The present invention relates to the field of magnetic field shielding, and particularly to a method for low-frequency magnetic field shielding. Background Art

[0002] When calibrating and calibrating high-precision magnetic sensors, simple static magnetic field shielding far from meets the calibration work of instrument equipment. There are increasingly high requirements for the noise indicators required by new sensors. Using traditional magnetic field shielding devices, that is, shielding devices made of high-permeability shielding materials to achieve a zero magnetic space with less residual magnetism in the internal working area only calibrates some indicators of the sensor, and there are deficiencies and insufficiencies in the calibration of the low-frequency noise indicators that play a decisive role in the sensor. Traditional shielding rooms mostly use the usage mode of combining shielding rooms with compensation coils to achieve the calibration and calibration work of higher sensitivity of the sensor, but there is a coupling relationship between the coil and the shielding layer, and there are non-linear errors in different frequency bands, which is not conducive to the calibration and calibration work of the technical indicators of the sensor.

[0003] With the in-depth research, by adjusting the skeleton mechanism of the magnetic shielding device and arranging the high-permeability materials in an orderly manner in layers, the shielding efficiency of the magnetic shielding device for low-frequency magnetic signals can be greatly reduced, avoiding the non-linear noise brought by the introduction of auxiliary equipment such as coils, and the magnetization defects brought to the shielding device by the use of coils.

[0004] In order to solve the shortcoming of the current magnetic shielding device for the shielding efficiency of low-frequency magnetic signals and the problem of magnetization of the magnetic shielding device caused by the use of traditional coils, the present invention proposes a method for realizing a low-frequency magnetic signal shielding device. Compared with traditional static magnetic shielding devices, it can achieve better shielding efficiency of low-frequency magnetic signals through the magnetic shielding device itself, and meet the calibration and verification work of the current magnetic sensor noise indicators. Summary of the Invention

[0005] In view of this, the present invention provides a method for low-frequency magnetic field shielding, including the following steps:

[0006] Step 1, perform a three-direction adjustable design on the support skeleton of the magnetic shielding device;

[0007] Step 2, stack and arrange high-permeability materials in a dumbbell shape, and the stacking size and interval of the high-permeability materials satisfy specific mathematical relationships;

[0008] Step 3, through the three-direction adjustment of the skeleton and the stacking arrangement of high-permeability materials, form a magnetic field shielding space for low-frequency noise in a given area.

[0009] Particularly, the adjustment directions of the support skeleton include three directions: left and right, up and down, and front and back.

[0010] In particular, in addition to meeting the structural strength requirements, the size adjustment needs to satisfy the following relationships:

[0011]

[0012] Where: ΔL represents the adjustment gap of the skeleton, D represents the low-frequency shielding coefficient required in the corresponding direction, a represents the size of the working area, and b represents the internal size of the shielding device.

[0013] In particular, the dumbbell-shaped laminated structure of the high-permeability material needs to satisfy the following relationships:

[0014]

[0015] Where:

[0016] S represents the overall shielding coefficient; k represents the shielding coefficient factor; μ r represents the relative permeability of the material; L represents the internal size of the shielding device; t represents the required thickness of the laminated shielding material.

[0017] In particular, the size specifications of the shielding material for each layer from the innermost layer to the middle layer of the lamination need to satisfy the following relationships:

[0018]

[0019] Where: L 1 represents the side length of the sub-layer, L 0 represents the side length of the innermost layer, K 0 represents the adjustment coefficient, which varies according to the internal space size.

[0020] In particular, the adjustment coefficient K 0 has a value range of 0.6 to 1.5.

[0021] Beneficial effects:

[0022] Through the adjustable support skeleton design of the present invention, the skeleton can be adjusted in three directions according to the ambient magnetic field and interference magnetic field states of the magnetic shielding device, enabling the shielding device to achieve a near-zero magnetic environment in a given area, thereby improving the shielding efficiency of low-frequency magnetic fields.

[0023] By arranging the high-permeability material in a dumbbell-shaped lamination according to the present invention and specifically designing the size of each layer of shielding material, the flow of magnetic flux inside the shielding device can be optimized, reducing the leakage of magnetic flux and further enhancing the shielding performance of low-frequency magnetic fields.

[0024] Through the size parameter calculation formula given by the present invention, the thickness and side length of each layer of shielding material can be accurately determined according to the required shielding coefficient, material permeability, and device size, theoretically guiding the optimized design of the shielding device.

[0025] Through the technical solution of the present invention, the non-linear error and magnetization defect caused by using a compensation coil in the traditional method can be avoided, and the shielding efficiency of the magnetic shielding device for low-frequency magnetic fields can be increased from the original 80 dB to more than 150 dB, meeting the requirements for calibrating the noise indexes of various magnetic sensors. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1a It is a schematic diagram for adjusting the left-right, up-down directions of the skeleton adjustment direction;

[0027] Figure 1b It is a schematic diagram for adjusting the front-back direction of the skeleton adjustment direction;

[0028] Figure 2a It is a top view schematic diagram of the lamination method of the high-permeability material;

[0029] Figure 2b It is a side view schematic diagram of the lamination method of the high-permeability material; DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] The present invention will be described in detail below with reference to the accompanying drawings and by way of examples.

[0031] The present invention provides a method for shielding low-frequency magnetic fields, which is characterized in that it includes the following steps:

[0032] Step 1, perform a three-direction adjustable design on the support skeleton of the magnetic shielding device, as Figure 1a and Figure 1b shown.

[0033] Step 2, stack and arrange high-permeability materials in a dumbbell shape, and the lamination size and interval of the high-permeability materials satisfy specific mathematical relationships;

[0034] Step 3, through the three-direction adjustment of the skeleton and the lamination arrangement of the high-permeability materials, form a magnetic field shielding space for low-frequency noise in a given area.

[0035] The present invention is realized by the following technical solution: perform a three-direction adjustable bone design on the support skeleton of the magnetic shielding device, and cooperate with the dumbbell-shaped stacking of high-permeability materials in each direction, as Figure 2a and Figure 2b shown, to achieve an effective shielding effect of the magnetic shielding device on low-frequency magnetic signals. The adjustable skeleton design includes adjustments in three directions: left-right, up-down, and front-back.

[0036] In addition to meeting the structural strength, the adjustment dimensions need to satisfy the following relationship:

[0037]

[0038] Where:

[0039] ΔL——Skew adjustment gap;

[0040] D——Low-frequency shielding coefficient required in the corresponding direction;

[0041] a——Working area size;

[0042] b——Internal size of the shielding device;

[0043] The dumbbell-shaped laminated structure of the high-permeability material shall satisfy the following relationship:

[0044]

[0045] In the formula:

[0046] S——Overall shielding coefficient;

[0047] k——Shielding coefficient factor;

[0048] μ r ——Relative permeability of the material;

[0049] L——Internal size of the shielding device;

[0050] t——Thickness required for the laminated shielding material.

[0051] The size specifications of each layer of shielding material from the innermost layer to the middle layer of the lamination shall satisfy the following relationship:

[0052]

[0053] In the formula:

[0054] L 1 ——Side length of the sub-layer;

[0055] L 0 ——Side length of the innermost layer;

[0056] K 0 ——Adjustment coefficient, generally taking 0.6 - 1.5 according to different internal space sizes.

[0057] In summary, the above is only the preferred embodiment of the present invention and is not used to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

[0058] For those skilled in the art, it is obvious that the embodiments of the present invention are not limited to the details of the above-described exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic characteristics of the embodiments of the present invention. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the embodiments of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be encompassed within the embodiments of the present invention. Any reference signs in the claims should not be construed as limiting the claimed invention. In addition, it is obvious that the word "comprising" does not exclude other units or steps, and the singular does not exclude the plural. The multiple units, modules or devices described in the system, apparatus or terminal claims can also be implemented by the same unit, module or device through software or hardware. The terms "first", "second", etc. are used to denote names and do not denote any particular order.

[0059] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the embodiments of the present invention and not to limit them. Although the technical solutions of the embodiments of the present invention have been described in detail with reference to the above preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the embodiments of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A low-frequency magnetic field shielding method, characterized in that : Includes the following steps: Step 1, designing a support frame of the magnetic shielding device to be adjustable in three directions; Step 2, using high magnetic permeability materials to stack in a dumbbell shape, wherein the stacking size and spacing of the high magnetic permeability materials satisfy a specific mathematical relationship; Step 3, by adjusting the three directions of the skeleton and stacking the high magnetic permeability materials, a magnetic field shielding space for low-frequency noise is formed in a given area.

2. The low-frequency magnetic field shielding method according to claim 1, characterized in that : The adjustment directions of the support frame include: left and right, up and down, and front and back.

3. The low-frequency magnetic field shielding method according to claim 2 is characterized in that : In addition to satisfying structural strength, the following relationships must be met when adjusting the size: Where: ΔL represents the frame adjustment gap, D represents the low-frequency shielding coefficient required to be achieved in the corresponding direction, a represents the size of the working area, and b represents the internal size of the shielding device.

4. The low-frequency magnetic field shielding method according to claim 3 is characterized in that : The dumbbell-shaped stacked structure of high magnetic permeability materials must satisfy the following relationship: Where: S represents the overall shielding coefficient; k represents the shielding coefficient factor; μ r Indicates the relative magnetic permeability of the material; L represents the inner dimension of the shielding device; t represents the required thickness of the laminated shielding material.

5. The low-frequency magnetic field shielding method according to claim 4, characterized in that : The size specifications of each layer of shielding material from the innermost layer to the middle layer must meet the following relationship: In the formula: L1 represents the side length of the secondary layer, L0 represents the side length of the innermost layer, and K0 represents the adjustment coefficient, which varies according to the size of the internal space.

6. The low-frequency magnetic field shielding method according to claim 5, characterized in that: The adjustment coefficient K0 ranges from 0.6 to 1.5.

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