Inductor and method of manufacturing the same

Abstract

The application provides an inductor and a preparation method thereof. The preparation method of the inductor comprises the following steps: providing a magnetic core, an enameled wire and a shielding material; winding the enameled wire on the magnetic core to form a coil; coating the shielding material on the surface of the coil, and performing orientation treatment on the shielding material coated on the surface of the coil, and then solidifying to obtain the inductor. The application provides the inductor and the preparation method thereof. The shielding material is coated on the surface of the coil, and the inductor is obtained through solidification, so that the whole process of the inductor is effectively shortened, the manufacturing efficiency is effectively improved, and automatic connection between processes is facilitated. The shielding material on the surface of the coil is not pressed, so that the magnetic core material does not need to be pressure-resistant, so that the damage of the magnetic core and the insulating layer of the coil can be avoided, the high-voltage resistance of the inductor is greatly improved, and the quality hidden danger of the prepared inductor is effectively solved.

Description

Technical Field

[0001] This application belongs to the field of inductor technology, and particularly relates to an inductor and its preparation method. Background Technology

[0002] Power inductors play a crucial role in energy conversion and voltage stabilization in switching power supply modules. An inductor consists of a metal coil and a magnetic core. Due to the high saturation magnetization of soft magnetic powder materials, they are currently the preferred material for power inductor cores. Inductors where the soft magnetic powder material is embedded within the metal coil during molding are called molded inductors. Molded inductors, with their high anti-saturation capability and low leakage flux, have become the mainstream power inductor product.

[0003] Currently, the manufacturing process of integrally molded inductors mainly includes many steps such as sieving and granulation, hot pressing, secondary hot pressing, and baking and curing. This process has the following drawbacks: First, the process is complex. After the coil is assembled, it needs to be hot pressed, then clamped and baked for a long time to cure and shape. Ball milling and polishing, surface insulation treatment, baking and shaping, laser peeling, and electroplating are not only numerous but also difficult to automate. Second, because a second hot pressing is required, the core can only use a core bonded to soft magnetic metal powder and resin, and cannot use a sintered core with better overall performance (sintered cores will break under high pressure). This limits the final electrical performance of the product, and the bonded core has low permeability, resulting in a higher copper consumption for the same inductance value. Third, after the coil is assembled, the outer shielding filling powder also needs to be heated and pressed. Due to the high pressure during molding, the powder and coil rub against each other during the extrusion process, damaging the insulation layer on their respective surfaces, significantly reducing the withstand voltage and creating a short-circuit hazard.

[0004] In summary, the current manufacturing process for integrally molded inductors is complex, and the resulting inductors have potential quality issues. Summary of the Invention

[0005] In view of this, this application provides an inductor and its preparation method to solve the technical problem that the existing inductor preparation process is complicated and the prepared inductor has potential quality problems.

[0006] In a first aspect, this application provides a method for fabricating an inductor, comprising the following steps:

[0007] We provide magnetic cores, enameled wires, and shielding materials.

[0008] The enameled wire is wound around the magnetic core to form a coil;

[0009] The shielding material is coated onto the surface of the coil, and the shielding material coated onto the surface of the coil is oriented, and then cured to obtain the inductor.

[0010] This effectively shortens the entire inductor manufacturing process, significantly improves manufacturing efficiency, and facilitates automated connection between different processes. The shielding material on the coil surface is not pressed, so the core material does not need to be pressure resistant. This eliminates the risk of damage to the core and coil insulation layer, greatly improving the inductor's ability to withstand high voltages and effectively solving the quality problems of the manufactured inductor.

[0011] In some embodiments, the method further includes the following steps prior to the step of coating the shielding material onto the coil surface:

[0012] The shielding material is magnetized to orient it, thereby facilitating uniform coating onto the surface of the coil.

[0013] In some embodiments, the magnetization process includes the following steps:

[0014] A magnetization device is provided, the magnetization device including a roller and a wire, the wire being disposed at the central axis of the roller, and the roller rotating about the central axis;

[0015] The shielding material is evenly placed on the surface of the roller;

[0016] The conductor is energized to magnetize the shielding material located on the surface of the roller.

[0017] In some embodiments, the orientation process includes the following steps:

[0018] An alignment device is provided, the alignment device including a substrate and electrodes spaced apart on the substrate, and the two ends of the enameled wire are respectively connected to the electrodes;

[0019] The electrode is connected to a current source, allowing current to flow through the coil and magnetizing the shielding material on the surface of the coil, thereby causing orientation.

[0020] In some embodiments, the shielding material comprises the following raw materials in parts by weight:

[0021] 100 parts of flake alloy powder;

[0022] 8-12 parts adhesive;

[0023] 0.1 to 0.2 parts of silane coupling agent;

[0024] Plasticizer 0.1 to 0.2 parts.

[0025] In some embodiments, the method for preparing the shielding material includes the following steps:

[0026] The flake alloy powder is mixed with the adhesive to obtain a first mixture;

[0027] The silane coupling agent and the plasticizer are mixed with the first mixture to obtain a second mixture;

[0028] The third mixture is ball-milled to obtain the shielding material.

[0029] In some embodiments, when mixing the silane coupling agent and the plasticizer with the first mixture, 8 to 15 parts by weight of solvent are added and stirred until the solvent is completely evaporated.

[0030] In some embodiments, the viscosity of the shielding material is greater than or equal to 30,000 Pa·s.

[0031] In some embodiments, the D50 of the flake alloy powder is 5 μm to 20 μm.

[0032] In some embodiments, the ratio of the length and width dimensions to the thickness of the flake alloy powder is 4 to 10.

[0033] In some embodiments, the ends of the enameled wire are tin-plated.

[0034] In some embodiments, the magnetic core is a sintered metal powder core.

[0035] Secondly, this application provides an inductor prepared using the preparation method described in the first aspect.

[0036] The inductor provided in this application uses sintered powder core material with a permeability of up to about 80 Henry, which is more than twice that of bonded powder core material with a permeability of 20 to 40 Henry. For the same inductance specification, the number of turns can be reduced, the coil cost can be reduced by 20% to 40%, and the rated current can be increased by 30% to 50%. The probability of short circuit in the prepared inductor is reduced to less than 1% of that in traditionally designed products. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1 This is a schematic flowchart of the inductor fabrication method provided in the embodiments of this application;

[0039] Figure 2 This is a schematic diagram of the structure in the inductor fabrication method provided in the embodiments of this application.

[0040] The attached icon numbers are as follows:

[0041] 1. Hopper; 2. Roller; 3. Support; 4. Wire; 5. Magnetic core; 6. Coil; 7. End; 8. Electrode; 9. Substrate; 10. Shielding. Detailed Implementation

[0042] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0043] It should also be understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0044] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0045] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0046] Furthermore, in the description of this application and the appended claims, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0047] References to "one embodiment" or "some embodiments" in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in some embodiments," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized. "A plurality" means two or more.

[0048] Firstly, such as Figure 1 As shown, this application provides a method for fabricating an inductor, comprising the following steps:

[0049] S1. Provide magnetic cores, enameled wires, and shielding materials;

[0050] S2. Wind the enameled wire around the magnetic core to form a coil;

[0051] S3. Apply shielding material to the surface of the coil, and then perform orientation treatment on the shielding material applied to the surface of the coil, and then cure it to obtain an inductor.

[0052] The inductor manufacturing method provided in this application involves coating a shielding material onto the surface of a coil, performing orientation treatment, and then curing to obtain the inductor. Compared with the integrated molding process of inductors in the prior art, this method reduces many process steps, such as eliminating the steps of hot pressing followed by clamping and baking, ball milling and polishing, surface insulation treatment, baking and shaping, laser peeling, and electroplating. Moreover, the remaining processes can be easily automated. The shielding material on the surface of the coil is not pressed, which requires the magnetic core material to have strong compressive strength. This can prevent damage to the magnetic core and the coil insulation layer, greatly improving the inductor's ability to withstand high voltages and effectively solving the quality problems of the manufactured inductor.

[0053] In some embodiments, in step S1, the magnetic core is a sintered metal powder core. In some embodiments, the raw materials for the magnetic core include: carbonyl iron powder, reduced iron powder, crushed alloy powder, amorphous iron powder, atomized alloy powder, and resin, wherein the resin accounts for 2% to 4% of the weight of the magnetic core powder. Moreover, the resin is a mixture of polyethylene glycol and silicone resin, with the ratio of the two resins between 1:4 and 1:1.

[0054] Furthermore, the preparation method of sintered metal powder cores includes: mixing the above raw materials and placing them in a dry mixer, stirring for more than 1 hour, then passing the mixture through a 40-mesh vibrating sieve, and pressing the sieved powder into a mold (usually T-shaped). The pressed magnetic core intermediate is then placed in an atmosphere furnace for sintering to obtain the sintered metal powder core. The heating rate should not exceed 10℃ / min, preferably 3℃ / min to 5℃ / min, with a maximum temperature of 700℃ to 750℃ and a holding time of 2 to 4 hours. Through the above sintering process, atomic diffusion can occur between the metal powders to form dense boundaries, thereby giving the magnetic core higher permeability and saturation magnetic induction.

[0055] In some embodiments, in step S1, the enameled wire is typically a copper wire with an outer layer of insulating varnish. In other embodiments, the enameled wire may also be an aluminum wire with an insulating varnish, etc.

[0056] Furthermore, in some embodiments, the two ends of the enameled wire are tin-plated. Tin plating has the following advantages: First, it prevents oxidation: Metals are easily affected by oxidation, especially in humid environments. Exposed metal wire ends are susceptible to oxidation by oxides in the environment, leading to poor contact. Tin plating forms a protective film on the metal surface, preventing oxidation. This prevents quality degradation during wiring due to oxidation of the wire end surface. Second, it improves conductivity: Tin plating forms a conductive layer on the surface of the copper wire end, thereby improving the conductivity of the metal surface. This increases the transmission efficiency of the connector. Third, it improves reliability: Tin plating increases the mechanical strength and reliability of the wire end, increasing the contact area between the wire end and the junction box, thus improving the stability and reliability of the contact. In machinery and its control systems, the quality of signal transmission is related to the stability and reliability of the system, so these systems require clean signal interfaces and stable contact. Fourth, it prevents the insulating rubber from becoming sticky and the wire core from turning black and brittle: Tin plating prevents the insulating rubber from becoming sticky, thus maintaining its performance and elasticity. At the same time, it can also prevent the wire core from turning black and brittle, extending the service life of the wire core. Fifth, it improves solderability: tin plating makes the ends of copper wire easier to solder, improving its solderability.

[0057] In some embodiments, in step S1, the shielding material comprises the following parts by weight of raw materials:

[0058] 100 parts of flake alloy powder;

[0059] 8-12 parts adhesive;

[0060] 0.1 to 0.2 parts of silane coupling agent;

[0061] Plasticizer 0.1 to 0.2 parts.

[0062] By using the above-mentioned components in parts by weight, a shielding material with good shielding effect can be obtained. The sheet alloy powder is preferably sheet iron-silicon-aluminum powder, which has high magnetic permeability. The binder is thermosetting epoxy resin or photosensitive resin, which can be rapidly cured and shaped under heating or light, facilitating further acceleration of inductor manufacturing. Plasticizers include, but are not limited to, phthalates, aliphatic diesters, fatty acid esters, polyphenol esters, polyol esters, epoxy hydrocarbons, and alkyl sulfonates. Common plasticizers include dibutyl phthalate, dioctyl phthalate, epoxidized soybean oil, tricresyl phosphate, triphenyl phosphate, dioctyl sebacate, and chlorowax. Silane coupling agents include, but are not limited to, JH-S69, JH-O187, JH-V171, JH-T28, JH-S75, JH-N308, JH-A110, JH-O174, and JH-A112.

[0063] In some embodiments, the optimal D50 range for the flake alloy powder is 5 μm to 20 μm, which balances flowability and final magnetic properties. This is because if the D50 of the flake alloy powder is too small (less than 5 μm), the material's permeability is too low, resulting in excessive leakage flux in the manufactured inductor and thus a low inductance. If the D50 is too large (greater than 20 μm), the powder thickness will inevitably be very thin, leading to very poor flowability of the shielding material during coating, resulting in uneven coating and numerous defects after curing, as well as poor bonding with the coil, thus resulting in low inductance. Therefore, it is optimal to control the D50 range of the flake alloy powder to be between 5μm and 20μm. In specific embodiments, the D50 of the flake alloy powder can be any value within the range of 5μm to 20μm, such as 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, 11μm, 12μm, 13μm, 14μm, 15μm, 16μm, 17μm, 18μm, 19μm, or 20μm.

[0064] In some embodiments, the ratio of the length and width dimensions to the thickness of the flake alloy powder is 4 to 10. In some specific embodiments, the ratio of the length and width dimensions to the thickness of the flake alloy powder can be any value within the range of 4 to 10, such as 4, 5, 6, 7, 8, 9, or 10.

[0065] In the application, relevant experiments were conducted on the D50 and aspect ratios of different flake alloy powders. The specific data are shown in the table below:

[0066]

[0067] Note: The inductance values ​​of sheet alloy powder with different D50 and corresponding length / width / thickness ratios are compared after molding, taking the 1μH specification as an example.

[0068] As can be seen from the table, when the length and width of the flake powder are 5μm to 20μm, the final inductance indicates that the coating has high permeability and a relatively smooth surface. When the size is less than 5μm, although the coating has a smooth surface and is tightly bonded to the coil, the permeability is not high enough. When the size is greater than 20μm, the coating shielding layer has a noticeable grainy texture, and the inductance is not high because the coating is not tightly bonded to the coil.

[0069] In some embodiments, the method for preparing the shielding material includes the following steps:

[0070] The flake alloy powder is mixed with the adhesive to obtain the first mixture;

[0071] The silane coupling agent and plasticizer are mixed with the first mixture to obtain the second mixture;

[0072] The third mixture was ball-milled to obtain the shielding material.

[0073] In some embodiments, the ball milling process specifically includes: placing the material in a ball milling jar and ball milling it at a low speed of 140 rpm to 200 rpm for 6 to 12 hours. The grinding balls are made of zirconia or agate, with a diameter of 5 mm to 10 mm, and the weight ratio of the grinding balls to the total weight of the slurry is 1:1. Through ball milling, the shielding material achieves a uniform particle size and fineness to meet the requirements of subsequent processes, facilitating its coating on the surface of the coil and improving the shielding effect.

[0074] In some embodiments, when mixing the silane coupling agent and plasticizer with the first mixture, 8 to 15 parts by weight of solvent are added and stirred until the solvent is completely evaporated. Further, the solvent includes acetone or anhydrous ethanol, preferably acetone. This is also to ensure that the components in the shielding material are fully mixed, thereby obtaining a shielding material with a suitable viscosity.

[0075] In some embodiments, the viscosity of the shielding material is greater than or equal to 30,000 Pa·s. This ensures that the shielding material adheres firmly to the coil surface, preventing it from falling off and facilitating subsequent curing and molding, thereby obtaining an inductor with better shielding performance. If the viscosity is too low, it will flow and fail to form a certain thickness on the coil surface; if the viscosity is too high, it will flow poorly and fail to uniformly cover the coil surface.

[0076] In applications, the shielding material on the coil surface is oriented to achieve a better shielding effect. Specifically, this involves oriented the sheet-like alloy powder within the shielding material. This is because the sheet-like alloy powder only achieves high permeability after curing when oriented; otherwise, it fails to achieve the desired performance.

[0077] In some embodiments, the method further includes the following steps prior to the step of coating the shielding material onto the coil surface:

[0078] The shielding material is magnetized to orient it, making it easier to coat evenly onto the coil surface. This is because, firstly, the magnetic permeability of the flake-shaped alloy powder only reaches its maximum after curing when oriented; otherwise, it fails to achieve the desired performance. Secondly, unoriented flake powder results in poor flowability, making it difficult to coat onto the coil surface.

[0079] In some embodiments, such as Figure 1 and Figure 2 As shown, the magnetization process includes the following steps:

[0080] A magnetization device is provided, which includes a roller 2 and a wire 4. The wire 4 is located at the central axis of the roller 2, and the roller 2 rotates around the central axis.

[0081] The shielding material is evenly placed on the surface of roller 2;

[0082] The wire 4 is connected to the current so as to magnetize the shielding material on the surface of the roller 2.

[0083] The orientation principle is as follows: When current flows through conductor 4, the magnetic field generated by conductor 4 forms concentric circles with conductor 4 as the axis. When the shielding material is in the magnetic field, the easy magnetization direction of the shielding material aligns with the direction of the magnetic field. For sheet alloy powder, the easy magnetization direction is in the plane of the sheet. Therefore, when energized, the sheet metal powder will be arranged parallel to the surface of roller 2. This achieves the orientation of the sheet alloy powder, facilitating subsequent coating onto the surface of coil 6.

[0084] In some embodiments, such as Figure 1 and Figure 2 As shown, the orientation process includes the following steps:

[0085] An alignment device is provided, comprising a substrate 9 and electrodes 8 spaced apart on the substrate 9, wherein the two ends 7 of the coil 6 are respectively connected to the electrodes 8;

[0086] Current is applied to electrode 8 so that current flows through coil 6, magnetizing the shielding material on the surface of coil 6 and causing it to orient itself.

[0087] When the assembled inductor is energized after connecting electrode 8, its own coil 6 generates a magnetic field. The magnetic field spreads from the core surrounded by coil 6 to the outer shielding material and then converges back to the core from the base. When energized, the flake alloy powder in the coating paste will align parallel to the inductor surface, thus maintaining its original orientation. The reason for reorientation is that during the coating of the shielding material onto the surface of coil 6, the internal flake alloy powder may become disordered. In order to maintain the oriented arrangement of the flake powder, it must be reoriented.

[0088] In some embodiments, such as Figure 2 As shown, the magnetic core includes a base and a core post. The main body of the enameled wire is wound around the core post, and the two ends of the enameled wire are inserted through the base and located on the side of the base away from the core post, so as to facilitate connection with the electrodes on the substrate.

[0089] like Figure 1 and Figure 2 As shown, the inductor manufacturing method provided in this application is as follows: A sintered metal powder core is used as the magnetic core 5. A flat enameled wire with tin-plated ends 7 is used. After the coil 6 is assembled, it is placed on the substrate 9 and fixed. The ends 7 are in contact with the electrodes 8 on the substrate. The shielding material is poured out from the suspended hopper 1. A roller 2 is located below the hopper 1 and is mounted on the support 3. The wire 4 passes through the roller and can carry a short current. The shielding material falls from the hopper 1 onto the roller 2 directly below. The current in the wire 4 at the central axis of the roller 2 magnetizes the shielding material on the roller 2. The sheet alloy powder in the shielding material is oriented and aligned. Then the roller 2 is pressed down and rolled over the assembled coil 6. A layer of shielding material is coated on the surface of the coil 6 to form a shielding part 10. At the same time as coating, a short current is applied to the electrodes 8 on the substrate to reorient the sheet alloy powder in the shielding part 10 formed on the surface of the coil. Then the inductor is solidified and shaped.

[0090] Secondly, this application provides an inductor prepared using the preparation method provided in the first aspect.

[0091] The inductor prepared in this application has the following advantages:

[0092] 1. The shielding part itself has a high adhesive content and good insulation, which greatly reduces the entire production process compared to the original. It eliminates steps such as clamping and baking after hot pressing, ball milling and polishing, surface insulation treatment, baking and shaping, laser peeling, and electroplating. Moreover, the remaining processes can be easily automated.

[0093] 2. The sintered metal powder core used has a permeability of up to about 80 Henry, which is more than twice that of the bonded powder core. For the same inductance specification, the number of coil turns can be reduced, thereby reducing the coil cost by 20% to 40%, and the rated current can be increased by 30% to 50%.

[0094] 3. The amount of sheet alloy powder used is reduced, and there is only a thin layer of shielding on the surface of the coil.

[0095] 4. The probability of short circuits in inductors has been reduced to less than 1% of that in traditionally designed products.

[0096] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0097] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A method for preparing an inductor, characterized in that, Includes the following steps: We provide magnetic cores, enameled wires, and shielding materials. The enameled wire is wound around the magnetic core to form a coil; The shielding material is coated onto the surface of the coil, and the shielding material coated onto the surface of the coil is oriented, and then cured to obtain the inductor; The procedure prior to the step of coating the shielding material onto the surface of the coil includes: The shielding material is magnetized to orient it, thereby facilitating uniform coating onto the surface of the coil. The shielding material includes sheet-like alloy powder, wherein the D50 of the sheet-like alloy powder is 5μm~20μm, and the ratio of its length and width to its thickness is 4~10. The magnetic core is a sintered metal powder core, and its preparation method includes: mixing magnetic core powder and pressing it, and sintering it in an atmosphere furnace with a heating rate ≤10℃ / min and a maximum temperature of 700~750℃ for 2~4h. The magnetization process includes the following steps: A magnetization device is provided, the magnetization device including a roller and a wire, the wire being disposed at the central axis of the roller, and the roller rotating about the central axis; The shielding material is evenly placed on the surface of the roller; The conductor is energized to magnetize the shielding material located on the surface of the roller; The orientation process includes the following steps: An alignment device is provided, the alignment device including a substrate and electrodes spaced apart on the substrate, and the two ends of the enameled wire are respectively connected to the electrodes; The electrode is connected to a current source, allowing current to flow through the coil and magnetizing the shielding material on the surface of the coil, thereby causing orientation.

2. The preparation method according to claim 1, characterized in that, The shielding material comprises the following raw materials in parts by weight: 100 parts of flake alloy powder; 8-12 parts adhesive; 0.1~0.2 parts of silane coupling agent; Plasticizer 0.1~0.2 parts.

3. The preparation method according to claim 2, characterized in that, The method for preparing the shielding material includes the following steps: The flake alloy powder is mixed with the adhesive to obtain a first mixture; The silane coupling agent and the plasticizer are mixed with the first mixture to obtain a second mixture; The second mixture is ball-milled to obtain the shielding material.

4. The preparation method according to claim 3, characterized in that, When mixing the silane coupling agent and the plasticizer with the first mixture, the process further includes adding 8-15 parts by weight of solvent and stirring until the solvent is completely evaporated; and / or The viscosity of the shielding material is greater than or equal to 30,000 Pa·s.

5. The preparation method according to any one of claims 1 to 4, characterized in that, The ends of the enameled wire are tin-plated; and / or The magnetic core is a sintered metal powder core.

6. An inductor, characterized in that, It is prepared by the preparation method according to any one of claims 1 to 5.

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