Soft magnetic material magnetic shielding performance test structure and test method

Abstract

According to the soft magnetic material magnetic shielding performance test structure and test method provided by the invention, the influence of mounting gaps and holes on the soft magnetic material can be quantitatively measured, the structure is easy to process, and the test process has small dependence on a site and a device. The soft magnetic material shell is made of a soft magnetic material to be tested; the left tongue-and-groove of the left half shell and the right tongue-and-groove of the right half shell are spliced, and a splicing gap is formed between the left tongue-and-groove and the right tongue-and-groove; the sensor supporting structure is fixed in the soft magnetic material shell, the sensor supporting structure is provided with an X-direction testing hole, a Y-direction testing hole and a Z-direction testing hole which are used for placing a testing sensor probe, the X-direction testing hole faces the axial direction of the soft magnetic material shell, the Y-direction testing hole faces the radial direction of the soft magnetic material shell, and the Z-direction testing hole faces the Z-direction testing hole. The Z-direction test hole faces the up-down direction of the soft magnetic material shell; the soft magnetic material shell is placed on the shell supporting structure; and the shielding shell section is made of a soft magnetic material which is the same as that of the soft magnetic material shell and is detachably mounted in the hole.

Description

Technical Field

[0001] The invention relates to a magnetic shielding performance testing structure and a testing method for soft magnetic materials. Background Art

[0002] Soft magnetic materials have the characteristics of high magnetic permeability, low magnetic resistance, easy magnetization and demagnetization, and are key materials for achieving electromagnetic shielding in magnetic shielding rooms. Common materials include silicon steel, Permalloy, manganese-zinc ferrite, etc. Due to the promotion and application of magnetic shielding rooms in many fields such as electrical equipment, biomedicine, and precision measurement, the requirements for magnetic shielding performance and size are constantly increasing, and the cost is also increasing. How to carry out precise design is also receiving more and more attention.

[0003] At present, the magnetic properties test methods of soft magnetic materials include the Epstein square circle method, the ring sample method and the single-piece measurement method. When designing a magnetic shielding room, the magnetic permeability of the soft magnetic material detected by this method is usually used to calculate the magnetic shielding coefficient. However, the magnetic permeability of soft magnetic materials is greatly affected by factors such as temperature and pressure, and the installation gaps and holes that must exist in the magnetic shielding room make the actual value of the shielding coefficient after the room is built differ greatly from the design value, which can easily cause design redundancy or failure to meet the standard. For example, the actual value of the shielding coefficient of the BMSR-2 of the German PTB is 75,000, which is 3 times higher than the design value of 24,000, while the actual value of the shielding coefficient of the Japanese COSMOS is 16,000, which is less than 1 / 12 of the design value of 200,000. For this reason, patents CN 114545306 A, CN114578274 A, CN 116224178 A, etc. all measure the magnetic properties of ring samples under different environments based on the ring sample method (GB / T 13012-2008). However, these methods directly measure the magnetic properties of the sample ring, which is very different from the magnetic properties of the large-scale plate as a whole. In principle, the methods disclosed in patents CN 205103388U and GB / T 39042-2020 can test the magnetic properties of bulk plates, but the test results are greatly affected by the thickness and grain orientation of the plates, and like the aforementioned methods, this type of method cannot quantitatively measure the impact of the splicing gaps and holes in the plates on the magnetic shielding performance of the material. In addition, existing methods for testing the magnetic properties of soft magnetic materials require the use of dedicated testing equipment and are completed on dedicated test benches in laboratories and workshops, so most companies can only outsource the work. Summary of the invention

[0004] The purpose of the present invention is to overcome the above-mentioned deficiencies in the prior art and to provide a magnetic shielding performance test structure and test method for soft magnetic materials with a rational structural design, which can quantitatively measure the influence of installation gaps and holes on soft magnetic materials, and the structure is easy to process, and the test process has little dependence on the site and equipment.

[0005] The technical solution adopted by the present invention to solve the above-mentioned problem is: a magnetic shielding performance test structure of a soft magnetic material, characterized in that: it comprises a soft magnetic material shell, a sensor support structure, a shell support structure and a shielding cylinder section; the soft magnetic material shell is made of the soft magnetic material to be tested, and the soft magnetic material shell comprises a left half shell and a right half shell; the left half shell is provided with a left tongue, and a hole is opened on the left hemispherical shell; the right half shell is provided with a right tongue; the left tongue and the right tongue are spliced, and there is a splicing gap between the left tongue and the right tongue; the sensor support structure is fixed on the soft magnetic material Inside the shell, an X-direction test hole, a Y-direction test hole and a Z-direction test hole for placing a test sensor probe are arranged on the sensor support structure, the X-direction test hole faces the axial direction of the soft magnetic material shell, the Y-direction test hole faces the radial direction of the soft magnetic material shell, the Z-direction test hole faces the up and down direction of the soft magnetic material shell, and the X-direction test hole, the Y-direction test hole and the Z-direction test hole are arranged vertically with respect to each other; the soft magnetic material shell is placed on the shell support structure; the shielding cylinder section is made of the same soft magnetic material as the soft magnetic material shell, and is detachably installed in the hole.

[0006] The left half shell body of the present invention comprises a left cylinder section and a left hemispherical shell. The left end of the left cylinder section is fixed on the left hemispherical shell, and the right end is provided with the left tongue and groove.

[0007] The left cylinder section of the present invention is cylindrical, and the left hemispherical shell is hemispherical.

[0008] The right half shell body of the present invention comprises a right cylinder section and a right hemispherical shell. The right end of the right cylinder section is fixed on the right hemispherical shell, and the left end is provided with the right tongue and groove.

[0009] The right cylinder section of the present invention is cylindrical, and the right hemispherical shell is hemispherical.

[0010] The left tongue and the right tongue described in the present invention are both step-shaped.

[0011] The sensor support structure described in the present invention includes a peripheral mounting plate and a central mounting block, wherein the peripheral mounting plate is fixed on the central mounting block; the peripheral mounting plate and the central mounting block are provided with the X-direction test holes, and the central mounting block is provided with the Y-direction test holes and the Z-direction test holes.

[0012] The invention is provided with an X-direction test hole, a Y-direction test hole and a Z-direction test hole located at the center of the soft magnetic material shell.

[0013] The sensor support structure of the present invention is made of non-magnetic material.

[0014] A method for testing a magnetic shielding performance test structure of a soft magnetic material, characterized in that it comprises the following steps:

[0015] (1) removing the soft magnetic material magnetic shielding performance test structure, and using a test sensor to measure the environmental magnetic field value at the test position where the soft magnetic material magnetic shielding performance test structure is located;

[0016] (2) Place the magnetic shielding performance test structure of the soft magnetic material at the test position, and make the X-axis test hole face the north-south direction, the Y-axis test hole face the east-west direction, and the Z-axis test hole face the sky-to-sky direction; fix the left half shell and quantitatively move the right half shell to the right, or fix the right half shell and quantitatively move the left half shell to the left, and control the splicing gap to the minimum value, that is, the manufacturing size error of the actual magnetic shielding room;

[0017] (3) Place the test sensor probe in the different Y-direction test holes, X-direction test holes and Z-direction test holes on the sensor support structure in turn, and lead the connecting lead of the test sensor through the shielding tube section and then lead it to the outside; read the internal magnetic field values ​​measured by the test sensor in each direction, and compare them with the environmental magnetic field values ​​to quantitatively analyze the magnetic shielding performance of the soft magnetic material shell;

[0018] (4) Remove the shielding tube section and repeat step (3), and at this time, the connecting lead of the test sensor is led to the outside through the hole; by comparing the magnetic field values ​​measured before and after removing the shielding tube section, the influence of the hole on the magnetic shielding performance of the chamber body can be quantitatively analyzed;

[0019] (5) Reinstall the shielding cylinder section, fix the left half shell, and quantitatively move the right half shell to the right, or fix the right half shell and quantitatively move the left half shell to the left, change the size of the splicing gap multiple times, and repeat step (3), so as to quantitatively test the influence of the splicing gap of the soft magnetic material on the magnetic shielding performance of the soft magnetic material.

[0020] Compared with the prior art, the present invention has the following advantages and effects:

[0021] 1) The structure is simple, easy to process, and the test process relies less on the site and equipment, which is suitable for engineering testing in non-laboratory environments;

[0022] 2) It can also quantitatively test and analyze the impact of the installation gap size of soft magnetic materials and the holes in the plate on the magnetic shielding performance of the material;

[0023] 3) Based on this patent, the magnetic permeability of the whole soft magnetic material plate and the closed chamber body can be obtained, which is closer to the actual value of the magnetic shielding room; BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the main structure of an embodiment of the present invention.

[0025] Figure 2 It is a left-view structural schematic diagram of an embodiment of the present invention.

[0026] Figure 3 It is a schematic structural diagram of a soft magnetic material shell according to an embodiment of the present invention.

[0027] Figure 4 It is a structural schematic diagram of left tongue and right tongue splicing in an embodiment of the present invention.

[0028] Figure 5 It is a structural schematic diagram of a sensor support structure according to an embodiment of the present invention.

[0029] Figure 6 It is a schematic diagram of the three-dimensional structure of an embodiment of the present invention.

[0030] Figure 7 This is a diagram of numerical simulation calculation results inside the shell of J85 Permalloy soft magnetic material in Example 1 of the present invention.

[0031] Figure 8 It is a curve diagram showing the relationship between the central magnetic flux density and the relative magnetic permeability in the soft magnetic material shell of the embodiment of the present invention. DETAILED DESCRIPTION

[0032] The present invention will be further described in detail below with reference to the accompanying drawings and by way of examples. The following examples are intended to explain the present invention but the present invention is not limited to the following examples.

[0033] The magnetic shielding performance testing structure of a soft magnetic material according to an embodiment of the present invention comprises a soft magnetic material shell, a sensor support structure 3 , a shell support structure 4 and a shielding cylinder section 6 .

[0034] The soft magnetic material shell is made of the soft magnetic material to be tested, and is specifically made of 3mm thick 1J85 Permalloy sheet. Considering the ductility and machining performance of 1J85 Permalloy, and the large drawing of the hemispherical shell, its processing technology includes: heating the 1J85 Permalloy sheet, hot stamping, laser cutting the hole 13, and annealing. The soft magnetic material shell includes a left half shell 1 and a right half shell 2.

[0035] The left half shell 1 comprises a left cylinder section 11 and a left hemispherical shell 12. The left end of the left cylinder section 11 is fixed on the left hemispherical shell 12, and the right end is provided with a left tongue and groove 111. The left tongue and groove 111 is a three-step step shape with a thickness of about 1 mm. The left cylinder section 11 is cylindrical, and the left hemispherical shell 12 is hemispherical. A hole 13 is opened on the left hemispherical shell 12.

[0036] The right half shell 2 comprises a right barrel section 21 and a right hemispherical shell 22. The right end of the right barrel section 21 is fixed on the right hemispherical shell 22, and the left end is provided with a right tongue and groove 211. The right tongue and groove 211 is a three-step step shape with a thickness of about 1 mm. The right barrel section 21 is cylindrical, and the right hemispherical shell 22 is hemispherical.

[0037] The left tongue 111 and the right tongue 211 are spliced ​​to form an overlapping connection through a step, so that the left half shell 1 and the right half shell 2 are connected into a whole. A splicing gap 23 is formed between the left tongue 111 and the right tongue 211.

[0038] The sensor support structure 3 is made of non-magnetic material, such as resin material, and is manufactured by 3D printing, and then is glued and fixed on the inner wall of the soft magnetic material shell. The sensor support structure 3 includes a peripheral mounting plate 31 and a central mounting block 32. The peripheral mounting plate 31 is fixed on the central mounting block 32, and there are multiple peripheral mounting plates 31, which are evenly surrounded by the central mounting block 32. In this embodiment, there are four peripheral mounting plates 31, and the peripheral mounting plates 31 are fan-shaped. A gap larger than the size of the test sensor 5 probe is left between two adjacent peripheral mounting plates 31, which is convenient for placing the test sensor 5 probe in the Y-axis test hole 33.

[0039] A plurality of X-direction test holes 34 for placing the probe of the test sensor 5 are provided on the peripheral mounting plate 31 and the central mounting block 32, and a Y-direction test hole 33 and a Z-direction test hole 35 for placing the probe of the test sensor 5 are also provided on the central mounting block 32. These X-direction test holes 34, Y-direction test holes 33 and Z-direction test holes 35 are located at different positions in the soft magnetic material shell; in terms of a three-dimensional coordinate system consisting of the axial direction of the soft magnetic material shell, the radial direction of the soft magnetic material shell, and the up-down direction of the soft magnetic material shell, the X-direction test hole 34 faces the axial direction of the soft magnetic material shell, the Y-direction test hole 33 faces the radial direction of the soft magnetic material shell, and the Z-direction test hole 35 faces the up-down direction of the soft magnetic material shell, and the X-direction test hole 34, the Y-direction test hole 33 and the Z-direction test hole 35 are arranged perpendicular to each other; during testing, the probe of the test sensor 5 is placed in different X-direction test holes 34, Y-direction test holes 33 or Z-direction test holes 35 in turn, and the magnetic field at different positions inside the soft magnetic material shell can be measured. Among them, an X-direction test hole 34, a Y-direction test hole 33 and a Z-direction test hole 35 are provided at the center of the soft magnetic material shell for measuring the magnetic field at the center of the soft magnetic material shell.

[0040] A V-shaped mounting surface 41 is provided on the shell support structure 4 , and the soft magnetic material shell is placed on the V-shaped mounting surface 41 , which can effectively fix the entire soft magnetic material shell.

[0041] The shielding cylinder section 6 is made of the same soft magnetic material as the soft magnetic material shell and is detachably installed in the hole 13 , and its aspect ratio is 10.

[0042] A method for testing a magnetic shielding performance test structure of a soft magnetic material comprises the following steps:

[0043] (1) removing the soft magnetic material magnetic shielding performance test structure, and using the test sensor 5 to measure the environmental magnetic field value H0 at the test position where the soft magnetic material magnetic shielding performance test structure is located;

[0044] (2) Place the magnetic shielding performance test structure of the soft magnetic material at the test position, and make the X-direction test hole 34 face the north-south direction, the Y-direction test hole 33 face the east-west direction, and the Z-direction test hole 35 face the sky-to-sky direction; fix the left half shell 1, and quantitatively move the right half shell 2 to the right, or fix the right half shell 2, and quantitatively move the left half shell 1 to the left, and control the splicing gap 23 to the minimum value, that is, the manufacturing size error of the actual magnetic shielding room, about 0.1 mm;

[0045] (3) Place the probe of the test sensor 5 in the different Y-direction test holes 33, X-direction test holes 34 and Z-direction test holes 35 on the sensor support structure 3 in turn, and lead the connecting wire of the test sensor 5 through the shielding tube section 6 and then lead it to the external instrument. Read the internal magnetic field values ​​in various directions measured by the test sensor 5 and compare them with the environmental magnetic field value H0 to quantitatively analyze the magnetic shielding performance of the soft magnetic material shell;

[0046] (4) Remove the shielding tube section 6 and repeat step (3), and at this time, the connecting lead of the test sensor 5 passes through the hole 13 and leads to the external instrument; by comparing the magnetic field values ​​measured before and after removing the shielding tube section 6, the influence of the hole 13 on the magnetic shielding performance of the chamber body can be quantitatively analyzed;

[0047] (5) Reinstall the shielding cylinder section 6, fix the left half shell 1, and quantitatively move the right half shell 2 to the right, or fix the right half shell 2 and quantitatively move the left half shell 1 to the left, change the size of the splicing gap 23 multiple times, control the spacing of the splicing gap 23 to 0.2mm, 0.4mm, 0.6mm, ..., 40mm, and repeat step (3), and you can quantitatively test the influence of the splicing gap of the soft magnetic material on the magnetic shielding performance of the soft magnetic material.

[0048] According to the test method provided by the present invention, the equivalent magnetic permeability of the soft magnetic material can also be calculated. Considering that the shapes of the soft magnetic material shells formed by connecting the left half shell 1 and the right half shell 2 are different, the equivalent magnetic permeability calculation method can also adopt different methods. The following are three embodiments:

[0049] (1) When the size of the left cylinder section 11 and the right cylinder section 21 is small, the shape of the soft magnetic material shell formed by connecting the left half shell 1 and the right half shell 2 can be regarded as a perfect sphere. For the perfect spherical soft magnetic material shell, its internal magnetic field value H1 is equal to the equivalent magnetic permeability u of the soft magnetic material. r The following relationship exists:

[0050]

[0051]

[0052] In the formula, u r is the equivalent magnetic permeability of the soft magnetic material, r o is the inner diameter of the soft magnetic material shell, t is the thickness of the soft magnetic material shell, that is, the thickness of the left half shell 1 and the right half shell 2, Hx, Hy, Hz are the magnetic field values ​​in the axial, radial, and up and down directions at the center of the soft magnetic material shell respectively;

[0053] (2) When the left half shell 1 and the right half shell 2 are connected to form a soft magnetic material shell in the shape of a regular hexahedron, for the regular hexahedron soft magnetic material shell, its internal magnetic field value H1 is equal to the equivalent magnetic permeability u of the soft magnetic material. r The following relationship exists:

[0054]

[0055] In the formula, u r is the equivalent magnetic permeability of the soft magnetic material, a is the side length of the regular hexahedron, and t is the thickness of the soft magnetic material shell, that is, the thickness of the left half shell 1 and the right half shell 2.

[0056] (3) When the shape of the soft magnetic material shell is irregular, for example, when the left cylinder section 11 and the right cylinder section 21 are larger in size, and the shape of the soft magnetic material shell is approximately a spherical cap-cylindrical shape, finite element simulation can be used to simulate and calculate the internal magnetic field value inside the soft magnetic material shell, including three-dimensional modeling of the soft magnetic material shell, meshing, magnetic permeability parametric scanning, and calculation of the magnetic field inside the soft magnetic material shell.

[0057] Due to manufacturing errors, when the axial gap L and radial gap H of the joint gap 23 are at least 0.1 mm, when the magnetic permeability of the soft magnetic material shell of 1J85 Permalloy is 100000, the finite element numerical calculation results of the magnetic flux density in the soft magnetic material shell model are as follows: Figure 7 On this basis, the magnetic permeability of the soft magnetic material 1J85 Permalloy is set as a parameterized variable, with values ​​taken in the interval [10000, 100000] with an interval of 5000, and the central magnetic flux density in the shell of the soft magnetic material under different magnetic permeabilities is solved to obtain the relationship curve between the central magnetic flux density and the relative magnetic permeability. The results are shown in Figure 8 .

[0058] For the calculated value of the internal magnetic field, the calculation method of the equivalent magnetic permeability of the soft magnetic material is as follows: the axial magnetic field value and the radial magnetic field value inside the soft magnetic material shell are tested through the aforementioned step (3), and the magnetic field value when the axial gap L and the radial gap H of the splicing gap 23 are both 0.1 mm is about 523.6 nT. Figure 8 The corresponding shell relative magnetic permeability 86950 is extracted from the curve, which is the equivalent magnetic permeability value of the 1J85 Permalloy soft magnetic material shell in this embodiment.

[0059] In addition, it should be noted that the shapes and names of the parts and components of the specific embodiments described in this specification may be different, and the above content described in this specification is only an example of the structure of the present invention. All equivalent changes or simple changes made based on the structure, features and principles described in the patent concept of the present invention are included in the protection scope of the patent of the present invention. Technicians in the technical field of the present invention can make various modifications or supplements to the specific embodiments described or replace them in a similar manner, as long as they do not deviate from the structure of the present invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

Claims

1. A magnetic shielding performance test structure for soft magnetic materials, characterized in that: The invention comprises a soft magnetic material shell, a sensor support structure, a shell support structure and a shielding cylinder section; the soft magnetic material shell is made of the soft magnetic material to be tested, and comprises a left half shell and a right half shell; the left half shell is provided with a left tongue, and a hole is opened on the left hemispherical shell; the right half shell is provided with a right tongue; the left tongue and the right tongue are spliced, and a splicing gap is provided between the left tongue and the right tongue; the sensor support structure is fixed in the soft magnetic material shell, and an X-direction test hole, a Y-direction test hole and a Z-direction test hole for placing a test sensor probe are provided on the sensor support structure, the X-direction test hole faces the axial direction of the soft magnetic material shell, the Y-direction test hole faces the radial direction of the soft magnetic material shell, the Z-direction test hole faces the up-down direction of the soft magnetic material shell, and the X-direction test hole, the Y-direction test hole and the Z-direction test hole are vertically arranged with each other; the soft magnetic material shell is placed on the shell support structure; the shielding cylinder section is made of the same soft magnetic material as the soft magnetic material shell, and can be detachably installed in the hole.

2. The magnetic shielding performance testing structure of soft magnetic materials according to claim 1, characterized in that: The left half shell body comprises a left cylinder section and a left hemispherical shell. The left end of the left cylinder section is fixed on the left hemispherical shell, and the right end is provided with the left tongue and groove.

3. The magnetic shielding performance testing structure of soft magnetic materials according to claim 2, characterized in that: The left cylinder section is cylindrical, and the left hemispherical shell is hemispherical.

4. The magnetic shielding performance testing structure of soft magnetic materials according to claim 1, characterized in that: The right half shell body comprises a right cylinder section and a right hemispherical shell. The right end of the right cylinder section is fixed on the right hemispherical shell, and the left end is provided with the right tongue and groove.

5. The magnetic shielding performance testing structure of soft magnetic materials according to claim 4, characterized in that: The right cylinder section is cylindrical, and the right hemispherical shell is hemispherical.

6. The magnetic shielding performance testing structure of soft magnetic materials according to claim 1, characterized in that: The left tongue and the right tongue are both step-shaped.

7. The magnetic shielding performance testing structure of soft magnetic materials according to claim 1, characterized in that: The sensor support structure includes a peripheral mounting plate and a central mounting block, wherein the peripheral mounting plate is fixed on the central mounting block; the peripheral mounting plate and the central mounting block are provided with the X-direction test holes, and the central mounting block is provided with the Y-direction test holes and the Z-direction test holes.

8. The magnetic shielding performance testing structure of soft magnetic materials according to claim 1, characterized in that: An X-direction test hole, a Y-direction test hole and a Z-direction test hole are arranged at the center of the soft magnetic material shell.

9. The magnetic shielding performance testing structure of soft magnetic materials according to claim 1, characterized in that: The sensor supporting structure is made of non-magnetic material.

10. A method for testing the magnetic shielding performance test structure of a soft magnetic material according to any one of claims 1 to 9, characterized in that: The steps include: (1) removing the soft magnetic material magnetic shielding performance test structure and using a test sensor to measure the environmental magnetic field value at the test position where the soft magnetic material magnetic shielding performance test structure is located; (2) Place the magnetic shielding performance test structure of the soft magnetic material at the test position, and make the X-axis test hole face the north-south direction, the Y-axis test hole face the east-west direction, and the Z-axis test hole face the sky-to-sky direction; fix the left half shell and move the right half shell to the right quantitatively, or fix the right half shell and move the left half shell to the left quantitatively, and control the splicing gap to the minimum value, that is, the manufacturing size error of the actual magnetic shielding room; (3) Place the test sensor probe in the different Y-direction test holes, X-direction test holes and Z-direction test holes on the sensor support structure in sequence, and lead the connecting wires of the test sensor through the shielding tube section and then lead them to the outside; By reading the internal magnetic field values ​​measured by the test sensor in various directions and comparing them with the ambient magnetic field values, the magnetic shielding performance of the soft magnetic material shell can be quantitatively analyzed; (4) Remove the shielding tube and repeat step (3), and this time the connecting lead of the test sensor passes through the hole and leads to the outside; By comparing the magnetic field values ​​measured before and after removing the shielding tube section, the effect of the hole on the magnetic shielding performance of the chamber can be quantitatively analyzed. (5) Reinstall the shielding cylinder section, fix the left half shell, and quantitatively move the right half shell to the right, or fix the right half shell and quantitatively move the left half shell to the left, change the size of the splicing gap multiple times, and repeat step (3), so as to quantitatively test the influence of the splicing gap of the soft magnetic material on the magnetic shielding performance of the soft magnetic material.

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