Shielding shell, preparation method thereof and fluxgate sensor

Abstract

The invention relates to a shielding shell, a preparation method thereof and a fluxgate sensor. The shielding shell for the fluxgate sensor comprises a bottom plate, a main body and a cover plate, the main body is of a structure with two open ends, the bottom plate is connected with one end of the main body to form a structure with one open end, and the cover plate is movably arranged at one end of the main body and forms a shell with an inner cavity with the main body and the bottom plate; a first electromagnetic shielding layer is arranged on the whole inner surface of the shell, and / or a second electromagnetic shielding layer is arranged on the whole outer surface of the shell. The whole inner surface or the whole outer surface of the shielding shell for the fluxgate sensor is provided with an electromagnetic shielding layer; the electromagnetic shielding layer can effectively shield interference of an external electric field and a high-frequency magnetic field through the reflection and absorption principle of the conductive material, so that the anti-magnetic interference performance of the fluxgate sensor is improved, and the measurement precision of the fluxgate sensor is further improved.

Description

Technical Field

[0001] The present invention relates to the technical field of sensors, and in particular to a shielding shell and a preparation method thereof, and a fluxgate sensor. Background Art

[0002] The fluxgate sensor mainly includes a magnetic core, an excitation coil, a measuring coil and a signal processor. It is a highly sensitive sensor that uses the nonlinear relationship between the magnetic induction intensity and the magnetic field intensity of the high permeability magnetic core in the measured magnetic field under the saturation excitation of the alternating magnetic field to measure weak magnetic fields. The fluxgate sensor can be used in many fields such as power systems, industrial automation, and electric vehicles. Its high precision, wide range, and high response speed make it play an important role in these fields. However, the measurement accuracy of the fluxgate sensor is easily interfered by the external magnetic field. In order to improve the measurement accuracy of the fluxgate sensor, it is necessary to further improve the sensor's anti-magnetic interference performance. Summary of the invention

[0003] Based on this, it is necessary to provide a shielding shell and a preparation method thereof and a fluxgate sensor, wherein the shielding shell has good anti-magnetic interference performance, thereby improving the anti-magnetic interference performance of the fluxgate sensor, and further improving the measurement accuracy of the fluxgate sensor.

[0004] The present application is implemented through the following technical solutions.

[0005] In one aspect of the present application, a shielding shell for a fluxgate sensor is provided, comprising a bottom plate, a main body and a cover plate; the main body is a structure with two ends open, the bottom plate is connected to one end of the main body to form a structure with one end open, the cover plate is movably arranged at one end of the main body, and forms a shell with an inner cavity together with the main body and the bottom plate;

[0006] The entire inner surface of the shell is provided with a first electromagnetic shielding layer, and / or the entire outer surface of the shell is provided with a second electromagnetic shielding layer.

[0007] The shielding shell for the above-mentioned fluxgate sensor includes a base plate, a main body and a cover plate, wherein a shell with an inner cavity can be formed between the base plate, the main body and the cover plate, so that the magnetic core, the coil and the signal processor can be placed in the inner cavity of the shielding shell; further, an electromagnetic shielding layer is provided on the entire inner surface or the entire outer surface of the shell; the electromagnetic shielding layer shell can effectively shield the external electric field and high-frequency magnetic field interference through the reflection and absorption principle of the conductive material, thereby improving the anti-magnetic interference performance of the fluxgate sensor, and then improving the measurement accuracy of the fluxgate sensor.

[0008] In some embodiments, the entire inner surface of the shell is provided with a first electromagnetic shielding layer, and the thickness of the first electromagnetic shielding layer is 0.3 mm to 0.5 mm.

[0009] In some embodiments, the entire outer surface of the shell is provided with a second electromagnetic shielding layer, and the thickness of the second electromagnetic shielding layer is 0.3 mm to 0.5 mm.

[0010] In some embodiments, the main body, the bottom plate and the cover plate are all made of nylon; and / or,

[0011] The raw materials for preparing the electromagnetic shielding layer include copper powder, styrene-butadiene copolymer, silicone powder, polyurethane emulsion, acrylic emulsion and organic solvent.

[0012] In some embodiments, the shielding shell further includes an insulating layer, and the insulating layer is disposed between the second electromagnetic shielding layer and the shell.

[0013] In some embodiments, the thickness of the insulating layer is 0.15 mm to 0.25 mm; and / or the material of the insulating layer is selected from at least one of polyvinyl chloride (PVC), low-density polyethylene (LDPE), high-density polyethylene (HDPE), linear low-density polyethylene (LLDPE), cross-linked polyethylene (XLPE), ethylene-propylene rubber (EPR), silicone rubber and fluorine-containing plastics.

[0014] In some embodiments, the shielding shell further includes an antistatic coating; the antistatic coating is disposed on the entire outer surface of the second electromagnetic shielding layer on a side away from the shell.

[0015] In some embodiments, the thickness of the antistatic coating is 1.5 mm to 3 mm; and / or,

[0016] The material of the antistatic coating includes one of acrylic acid and polyurethane and silicone powder.

[0017] A second aspect of the present application provides a method for preparing the above-mentioned shielding shell, comprising the following steps:

[0018] Forming electromagnetic shielding layers on the entire inner surface and / or the entire outer surface of the main body, the cover plate and the bottom plate respectively;

[0019] The main body, the cover plate and the bottom plate are then connected to form the shell with the inner cavity.

[0020] A third aspect of the present application provides a fluxgate sensor, which includes the above-mentioned shielding shell and a coil, a magnetic core and a signal processor fixed to the inner cavity of the shielding shell. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the conventional technology, the drawings required for use in the embodiments or the conventional technology descriptions are briefly introduced below. Obviously, the drawings described below are merely embodiments of the present application, and ordinary technicians in this field can obtain other drawings based on the disclosed drawings without paying any creative work.

[0022] Figure 1 It is a schematic diagram of the structure of a fluxgate sensor in one embodiment of the present application, wherein the cover plate in the shielding shell is not shown.

[0023] Figure 2 This is a schematic structural diagram of a shielding shell for a fluxgate sensor in one embodiment of the present application, wherein the cover plate is not shown.

[0024] Figure 3 It is a front view of a shielding shell for a fluxgate sensor in one embodiment of the present application.

[0025] Figure 4 It is a schematic cross-sectional view of the main body of the shielding shell for the fluxgate sensor in one embodiment of the present application.

[0026] Reference numerals:

[0027] 1. Shielding shell for fluxgate sensor; 11. Cover plate; 12. Main body; 13. Bottom plate; 14. Grounding assembly; 15. Fixing column; 121. First electromagnetic shielding layer; 122. Insulating layer; 123. Second electromagnetic shielding layer; 124. Antistatic coating; 141. Grounding wire; 142. Grounding terminal;

[0028] 2. Coil. DETAILED DESCRIPTION

[0029] In order to facilitate the understanding of the present invention, the present invention is described more comprehensively below. And preferred embodiments of the present invention are given. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. It should be understood that the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0031] In the description of the present invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0032] The weight of the relevant components mentioned in the description of the embodiments of the present invention may not only refer to the specific content of each component, but also indicate the weight ratio between the components. Therefore, as long as the content of the relevant components is proportionally enlarged or reduced according to the description of the embodiments of the present invention, it is within the scope disclosed in the description of the embodiments of the present invention. Specifically, the weight described in the description of the embodiments of the present invention may be a mass unit known in the chemical industry such as μg, mg, g, kg, etc.

[0033] See also Figure 1~Figure 3 In one embodiment of the present application, a shielding shell 1 for a fluxgate sensor is provided, comprising a bottom plate 13, a main body 12 and a cover plate 11 ( Figure 1 The fluxgate sensor and Figure 2 The structural schematic diagram of the shielding shell 1 does not show the cover structure. Figure 1 The fluxgate sensor also does not provide structures such as the electromagnetic shielding layer in the shielding shell); the main body 12 is a structure with openings at both ends, the bottom plate 13 is connected to one end of the main body 12 to form a structure with an opening at one end, the cover plate 11 is movably arranged at one end of the main body 12, and forms a shell with an inner cavity together with the main body 12 and the bottom plate 13; wherein the entire inner surface of the shell 1 is provided with a first electromagnetic shielding layer 121, and / or the entire outer surface of the shell 1 is provided with a second electromagnetic shielding layer 123.

[0034] The entire inner surface of the shielding shell 1 refers to the inner wall of the cavity formed by the cover plate 11, the main body 12 and the bottom plate 13 connected to each other, which includes the inner surface of the cover plate 11, the inner surface of the main body 12 and the inner surface of the bottom plate 13. Similarly, the entire inner surface of the shielding shell 1 includes the outer surface of the cover plate 11, the outer surface of the main body 12 and the outer specific surface of the bottom plate 13.

[0035] The shielding shell 1 for the fluxgate sensor comprises a bottom plate 13, a main body 12 and a cover plate 11, wherein a shell having an inner cavity can be formed between the bottom plate 13, the main body 12 and the cover plate 11, so that the magnetic core ( Figure 1 Not shown), coil 2 and signal processor ( Figure 1(not shown) is placed in the inner cavity of the shielding shell 1; further, an electromagnetic shielding layer is provided on the entire inner surface or the entire outer surface of the shell; the electromagnetic shielding layer can effectively shield the electric field and high-frequency magnetic field interference from the outside through the reflection and absorption principle of the conductive material, thereby improving the anti-magnetic interference performance of the fluxgate sensor, and further improving the measurement accuracy of the fluxgate sensor.

[0036] In some embodiments, the entire inner surface of the shielding shell 1 is provided with a first electromagnetic shielding layer 121 , and the thickness of the first electromagnetic shielding layer is 0.3 mm to 0.5 mm.

[0037] In some embodiments, the entire outer surface of the shielding shell 1 is provided with a second electromagnetic shielding layer 123 , and the thickness of the second electromagnetic shielding layer is 0.3 mm to 0.5 mm.

[0038] In some embodiments, the material of the first battery shielding layer and the material of the second battery shielding layer may be the same or different.

[0039] See also Figure 2 In some embodiments, the entire inner surface of the shielding shell 1 is provided with a first electromagnetic shielding layer 121, and the entire outer surface of the shielding shell 1 is provided with a second electromagnetic shielding layer 123. By providing electromagnetic shielding layers on both the inner and outer surfaces of the shielding shell 1, the interference of external electric fields and high-frequency magnetic fields can be further improved, thereby improving the anti-magnetic interference performance of the fluxgate sensor.

[0040] In some embodiments, the raw materials for preparing the electromagnetic shielding layer include copper powder, styrene-butadiene copolymer, silicone powder, polyurethane emulsion, acrylic emulsion and organic solvent. It can be understood that the copper powder, styrene-butadiene copolymer, silicone powder, polyurethane emulsion and acrylic emulsion are all commercially available products commonly used in the art.

[0041] In some embodiments, the raw materials for preparing the electromagnetic shielding layer include the following components by weight:

[0042] 20 to 40 parts of copper powder, 5 to 15 parts of styrene-butadiene copolymer, 5 to 15 parts of silicone powder, 10 to 30 parts of polyurethane emulsion, 5 to 15 parts of acrylic emulsion and 10 to 30 parts of organic solvent.

[0043] In some embodiments, organic solvents include, but are not limited to, ethanol.

[0044] In some embodiments, the material of the body 12 includes but is not limited to nylon.

[0045] In some embodiments, the main body 12 may be a columnar structure with openings at both ends. Further, the main body may be a cylindrical structure or a prismatic structure, or other columnar structures.

[0046] In some embodiments, the main body 12 is further provided with a through hole, and the wire connected to the coil in the fluxgate sensor can be connected to the coil through the through hole, so that the fluxgate sensor is connected to a power source.

[0047] In some embodiments, the material of the bottom plate 13 includes but is not limited to nylon.

[0048] In some embodiments, the material of the cover plate 11 includes but is not limited to nylon.

[0049] See also Figure 4 In some embodiments, the shielding shell 1 further includes an insulating layer 122, and the insulating layer 122 is disposed between the shielding shell 1 and the second electromagnetic shielding layer 123. The insulating layer 122 disposed between the shielding shell 1 and the second electromagnetic shielding layer 123 can play a role in electrical isolation, preventing current from directly flowing from the second electromagnetic shielding layer 123 to the shielding shell or related fluxgate sensor components inside the shielding shell, reducing the risk of electrical failure and ensuring the safety of the sensor operation.

[0050] In some embodiments, the material of the insulating layer 122 is selected from at least one of polyvinyl chloride (PVC), low density polyethylene (LDPE), high density polyethylene (HDPE), linear low density polyethylene (LLDPE), cross-linked polyethylene (XLPE), ethylene propylene rubber (EPR), silicone rubber and fluorine-containing plastics.

[0051] In some embodiments, the thickness of the insulating layer 122 is 0.15 mm to 0.25 mm. It is understood that the thickness of the insulating layer 122 can be 0.15 mm, 0.18 mm, 0.20 mm, 0.22 mm, 0.24 mm or 0.25 mm. Further, the thickness of the insulating layer can be a range value consisting of any two of the above point values ​​as end values.

[0052] In some embodiments, the shielding shell 1 further includes an antistatic coating 124; the antistatic coating 124 is disposed on the entire outer surface of the second electromagnetic shielding layer 123 on the side away from the shielding shell 1. The antistatic coating 124 can effectively reduce the resistance of the material surface, thereby preventing the accumulation and generation of static electricity, preventing static electricity interference from affecting the measurement accuracy and stability of the fluxgate sensor, and can shield the external electrostatic field to a certain extent, reducing the impact on the internal circuit.

[0053] In some embodiments, the material of the antistatic coating 124 includes one of acrylic acid and polyurethane and silicone powder; it may also be other materials with antistatic effect commonly used in the art.

[0054] In some embodiments, the thickness of the antistatic coating 124 is 1.5 mm to 3 mm. It is understood that the thickness of the antistatic coating 124 can be 1.5 mm, 1.6 mm, 1.8 mm, 2.0 mm, 2.2 mm, 2.4 mm, 2.5 mm, 2.6 mm, 2.8 mm or 3 mm. Further, the thickness of the antistatic coating 124 can be a range value consisting of any two of the above point values ​​as end values.

[0055] Continue reading Figure 4 In some embodiments, the shielding shell 1 also includes a grounding component 14 connected to the second electromagnetic shielding layer 123. The grounding component 14 includes a grounding wire 141 and a grounding terminal 142; one end of the grounding wire 141 is connected to the second electromagnetic shielding layer, and the other end of the grounding wire 141 is connected to the grounding terminal 142. The grounding wire 141 serves as a connection point between the grounding terminal 142 and the shielding shell 1, which can ensure that the connection between the grounding terminal 142 and the shielding shell 1 is firm and reliable, and provide good grounding conditions for the shielding shell 1. At the same time, the grounding wire 141 tightly connects the shielding shell 1 and the grounding terminal 142 to form a complete electrical circuit, so that the shielding effect of the second electromagnetic shielding layer 123 on the external electromagnetic field can be fully exerted, reducing the influence of electromagnetic interference on the measurement accuracy of the fluxgate sensor.

[0056] In some embodiments, the grounding component 14 can be connected to a portion of the electromagnetic shielding layer 123 on the outer surface of the base plate 13, to a portion of the electromagnetic shielding layer 123 on the outer surface of the main body 12, or to a portion of the electromagnetic shielding layer 123 on the outer surface of the cover plate 11.

[0057] In some embodiments, the shielding shell 1 further includes a fixing post 15. The fixing post 15 is disposed in the inner cavity of the shielding shell 1 and is connected and fixed to the bottom plate 13. The component coil 2 in the fluxgate sensor can be sleeved on the fixing post 15, so that the coil can be stably disposed in the cavity of the shielding shell 1.

[0058] Continue reading Figure 1 In one embodiment of the present application, a fluxgate sensor is provided, comprising the above-mentioned shielding shell 1 and a coil 2 fixed in the inner cavity of the shielding shell 1, a magnetic core ( Figure 1 ) and a signal processor ( Figure 1 The signal processor amplifies the signal through an amplifier to improve the signal-to-noise ratio of the signal and the accuracy of subsequent processing. The coil 2 is a coil conventionally used in the art, specifically including an excitation coil and a measurement coil. The function of the coil is to generate and adjust the magnetic field; further, the connection method of the coil 2, the magnetic core and the signal processor adopts the connection method conventionally used in the art, which will not be described in detail in this embodiment.

[0059] In some embodiments, the fluxgate sensor further includes a filter disposed in the inner cavity of the shielding shell 1 and connected to the signal processor. The signal amplified in the signal processor may contain various noise and interference components, such as power supply noise, electromagnetic interference, etc. The signal is filtered by the filter to remove unnecessary frequency components and retain the effective signal related to the measured current; the filter integrated inside the shielding shell 1 can suppress the low-frequency magnetic field, which helps to reduce the interference of the low-frequency magnetic field on the sensor signal and improve the accuracy of the measurement.

[0060] In one embodiment of the present application, a method for preparing the above-mentioned shielding shell is provided, comprising the following steps:

[0061] Electromagnetic shielding layers are formed on the entire inner surface and / or the entire outer surface of the main body 12, the cover plate 11 and the bottom plate 13 respectively;

[0062] The main body 12, the cover plate 11 and the bottom plate 13 are then connected to form a shell having an inner cavity.

[0063] In some embodiments, the step of forming an electromagnetic shielding layer on the entire inner surface of the main body 12 , the cover plate 11 , and the bottom plate 13 includes the following steps S10 - S50 .

[0064] S10, surface treatment step: cleaning, degreasing and derusting the inner surfaces of the main body 12, the cover plate 11 and the bottom plate 13 respectively to ensure surface smoothness and flatness.

[0065] In some embodiments, the cleaning process includes at least one of physical cleaning and chemical cleaning.

[0066] In some embodiments, the cleaning process includes using a brush, sandpaper or other tool to remove dust, impurities and attachments on the inner surfaces of the main body 12 , the cover plate 11 and the bottom plate 13 by friction.

[0067] In some embodiments, chemical cleaning includes soaking or wiping the inner surfaces of the main body 12 , the cover plate 11 , and the bottom plate 13 with a cleaning agent.

[0068] In some embodiments, the degreasing treatment includes at least one of organic solvent degreasing and alkaline degreasing. Further, the step of organic solvent degreasing includes: wiping or soaking the surface of the housing with an organic solvent to remove grease and stains. Alkaline degreasing includes placing the housing in an alkaline degreasing liquid to remove grease through a chemical reaction. Further, the organic solvent can be gasoline or alcohol.

[0069] In some embodiments, after the oil removal treatment, the process further includes rinsing with clean water and performing a neutralization treatment to prevent residual alkaline substances from affecting subsequent processes.

[0070] In some embodiments, the rust removal process includes at least one of physical rust removal and chemical rust removal.

[0071] In some embodiments, the step of physical rust removal includes: using tools such as grinding wheels, sandpaper, and wire brushes to remove rust and oxide layers on the surface of the shell by mechanical friction.

[0072] In some embodiments, the chemical rust removal treatment includes soaking or spraying the shell surface with a pickling solution. Further, the pickling solution can be hydrochloric acid or sulfuric acid.

[0073] In some embodiments, after the rust removal treatment, it also includes rinsing with clean water and performing a neutralization treatment to prevent residual acid from corroding the shell material.

[0074] In some embodiments, the surface treatment step further includes polishing the inner surfaces of the main body 12, the cover plate 11 and the bottom plate 13 respectively to remove tiny flaws and uneven portions on the surface, thereby improving the adhesion of the electromagnetic shielding material coating.

[0075] S20 , spraying preparation step: configuring the electromagnetic shielding layer paint according to the component proportions of the first electromagnetic shielding layer 121 set on the entire inner surface of the shielding shell 1 .

[0076] S30, spraying construction step: spray the above-mentioned coating evenly on the inner surface of the main body 12, the cover plate 11 and the bottom plate 13 to form a desired coating. Further, the spraying construction step also includes inspecting the coating after spraying to ensure that the coating has no defects such as missing coating, sagging, bubbles, etc., and performing supplementary spraying or re-spraying when necessary.

[0077] In some embodiments, electrostatic spraying equipment or air spraying equipment may be used for spraying. According to different coating properties and spraying requirements, a suitable spraying method is selected to ensure uniformity and quality of the coating.

[0078] In some embodiments, the thickness of the coating may be 65 mm to 130 mm.

[0079] S40, curing treatment step: heat and cure the sprayed coating; the heating and curing treatment can make the first electromagnetic shielding layer 121 more firmly bonded to the main body 12, the cover plate 11 and the base plate 13 (that is, the shielding shell); at the same time, it can also improve the durability of the first electromagnetic shielding layer 121.

[0080] In some embodiments, when the coating is subjected to high temperature heating and curing treatment, the heating temperature is 140°C to 180°C.

[0081] In some embodiments, when the coating is subjected to high temperature heating and curing treatment, the heating time is 8 minutes to 15 minutes.

[0082] S50, cooling treatment step: air-cool or water-cool the main body 12, cover plate 11 and bottom plate 13 after the curing treatment. Cooling the main body 12, cover plate 11 and bottom plate 13 after heating and curing by air-cooling or water-cooling helps to maintain the microstructure stability of the magnetic shielding layer material; at the same time, it can quickly reduce the temperature of the material, slow down or inhibit the chemical reaction of the magnetic shielding layer material with oxygen, moisture and the like in the environment under high temperature conditions, thereby maintaining the chemical properties of the magnetic shielding layer material stable. Furthermore, during the spraying process, the magnetic shielding layer material will be affected by the high temperature, thereby generating thermal stress; by cooling treatment, the temperature of the material can be reduced, thereby reducing the thermal stress, thereby inhibiting the deformation or damage of the material caused by the thermal stress.

[0083] In some embodiments, the step of forming an electromagnetic shielding layer on the entire outer surface of the main body 12, the cover plate 11 and the bottom plate 13 is consistent with the above-mentioned step of forming an electromagnetic shielding layer on the entire outer surface of the main body 12, the cover plate 11 and the bottom plate 13, and will not be repeated here.

[0084] In order to make the purpose, technical solutions and advantages of the present invention more concise and clear, the present invention is described with the following specific embodiments, but the present invention is by no means limited to these embodiments. The embodiments described below are only preferred embodiments of the present invention, which can be used to describe the present invention and cannot be understood as limiting the scope of the present invention. It should be pointed out that any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

[0085] In order to better illustrate the present invention, the present invention is further described below in conjunction with the embodiments. The following are specific embodiments.

[0086] The following are specific embodiments.

[0087] Example 1

[0088] See also Figure 2 This embodiment provides an electromagnetic shielding shell 1, including a bottom plate 13, a main body 12 and a cover plate 11; the main body 12 is a structure with two ends open, the bottom plate 13 is connected to one end of the main body 12 to form a structure with one end open, and the cover plate 11 ( Figure 1 The shielding shell 1 is provided with a first electromagnetic shielding layer 121 on the entire inner surface, and a second electromagnetic shielding layer 123 on the entire outer surface. The thickness of the first electromagnetic shielding layer 121 is 0.2 mm, and the thickness of the second electromagnetic shielding layer 123 is 0.2 mm.

[0089] Specifically, the preparation method of the electromagnetic shielding shell 1 is as follows:

[0090] 1. Surface treatment steps: Clean, degrease and rust the inner and outer surfaces of the main body 12, cover plate 11 and bottom plate 13 respectively. Then use sandpaper to polish the inner surfaces of the main body 12, cover plate 11 and bottom plate 13 to remove minor flaws and uneven parts on the surface; finally rinse with clean water and wipe dry.

[0091] 2. Spraying preparation step: configure an electromagnetic shielding layer coating according to the component ratio of the first electromagnetic shielding layer 121 set on the entire inner surface of the shielding shell 1; wherein the components of the electromagnetic shielding layer coating include: 30 parts of copper powder, 10 parts of polymer block copolymer, 10 parts of silicone powder, 10 parts of polyurethane emulsion, 20 parts of acrylic emulsion and 20 parts of ethanol.

[0092] 3. Spraying construction steps: Use electrostatic spraying equipment to evenly spray the coating prepared in step (2) onto the main body 12, cover plate 11 and bottom plate 13 to form a coating with a thickness of 80 mm on the inner and outer surfaces after surface treatment; check that the coating after spraying has no defects such as missing coating, sagging, bubbles, etc.

[0093] 4. Curing step: The main body 12, cover plate 11 and bottom plate 13 with coatings on both the inner and outer surfaces obtained in step (3) are cured at 150° C. for 10 minutes.

[0094] 5. Cooling treatment step: After the heating and curing is completed, the sample is taken out and the high-temperature main body 12, cover plate 11 and bottom plate 13 are cooled by water cooling.

[0095] 6. Connect the cooled main body 12, cover plate 11 and bottom plate 13 to obtain a magnetic shielding shell.

[0096] When the magnetic shielding shell is applied to a fluxgate sensor, compared with a fluxgate sensor without the magnetic shielding shell, the sensor with the shielding shell has stronger anti-interference capability and higher measurement accuracy.

[0097] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0098] The above-mentioned embodiments only express several implementation methods of the present invention, and the description is relatively specific and detailed, but it cannot be understood as limiting the scope of the invention patent. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be based on the attached claims, and the description can be used to interpret the content of the claims.

Claims

1. A shielding shell for a fluxgate sensor, characterized in that: It comprises a bottom plate, a main body and a cover plate; the main body is a structure with two ends open, the bottom plate is connected to one end of the main body to form a structure with one end open, the cover plate is movably arranged at one end of the main body, and forms a shell with an inner cavity together with the main body and the bottom plate; The entire inner surface of the shell is provided with a first electromagnetic shielding layer, and / or the entire outer surface of the shell is provided with a second electromagnetic shielding layer.

2. The shielding shell according to claim 1, characterized in that: The entire inner surface of the shell is provided with a first electromagnetic shielding layer, and the thickness of the first electromagnetic shielding layer is 0.3 mm to 0.5 mm.

3. The shielding shell according to claim 1, characterized in that: The entire outer surface of the shell is provided with a second electromagnetic shielding layer, and the thickness of the second electromagnetic shielding layer is 0.3 mm to 0.5 mm.

4. The shielding shell according to any one of claims 1 to 3, characterized in that: The main body, the bottom plate and the cover plate are all made of nylon; and / or, The raw materials for preparing the electromagnetic shielding layer include copper powder, styrene-butadiene copolymer, silicone powder, polyurethane emulsion, acrylic emulsion and organic solvent.

5. The shielding shell according to claim 3, characterized in that: The shielding shell further includes an insulating layer, and the insulating layer is arranged between the second electromagnetic shielding layer and the shell.

6. The shielding shell according to claim 5, characterized in that: The thickness of the insulating layer is 0.15 mm to 0.25 mm; and / or, the material of the insulating layer is selected from at least one of polyvinyl chloride (PVC), low-density polyethylene (LDPE), high-density polyethylene (HDPE), linear low-density polyethylene (LLDPE), cross-linked polyethylene (XLPE), ethylene-propylene rubber (EPR), silicone rubber and fluorine-containing plastics.

7. The shielding shell according to any one of claims 3, 5 to 6, characterized in that: The shielding shell further includes an antistatic coating; the antistatic coating is disposed on the entire outer surface of the second electromagnetic shielding layer on a side away from the shell.

8. The shielding shell according to claim 7, characterized in that: The thickness of the antistatic coating is 1.5 mm to 3 mm; and / or, The material of the antistatic coating includes one of acrylic acid and polyurethane and silicone powder.

9. The method for preparing a shielding shell according to any one of claims 1 to 8, characterized in that: The steps include: forming an electromagnetic shielding layer on the entire inner surface and / or the entire outer surface of each of the main body, the cover plate and the bottom plate; The main body, the cover plate and the bottom plate are then connected to form the shell with the inner cavity.

10. A fluxgate sensor, characterized in that: The fluxgate sensor comprises a shielding shell as described in any one of claims 1 to 8 and a coil, a magnetic core and a signal processor fixed in an inner cavity of the shielding shell.

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