Inductor forming method and inductor

Abstract

An inductor forming method and an inductor. The inductor forming method comprises the following steps: S10, preparing: providing magnetic glue (100) and a coil; S20, forming: putting the coil into a forming mold, applying the magnetic glue (100) to coat the coil, and heating to form a magnet; S30, baking: heating and baking the formed magnet; and S40, bending: bending two terminals of the coil so that the two terminals are attached to the magnet to form an electrode.

Description

Inductor molding method and inductor

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on November 24, 2023, with application number 202311579722.2, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the technical field of electronic components, for example, to a forming method of an inductor and an inductor. Background Art

[0003] Inductors, also known as inductor coils, convert electrical energy into magnetic energy and store it, making them essential components of electronic circuits. One-piece molded inductors consist of a magnet, coil windings, and terminals. The magnet is die-cast from a winding body embedded within a metal magnetic powder. The terminal pins extend from the winding body and are formed directly on the surface of the base. Their fully enclosed structure provides effective magnetic shielding, effectively reducing electromagnetic interference and noise.

[0004] During the molding process, all one-piece molded inductors are wound with round or flat wire to a specific inner diameter and number of turns according to product requirements. After that, they are filled with powder and pressed into shape. The inductor is then baked and cured. After curing, the terminals on both sides of the inductor are bent to create a molded inductor that can be mounted on the bottom. Because the coil expands outward during the molding process, a reserve must be reserved for the coil's expansion, reducing the inductor's space utilization. Furthermore, because the molding pressure is typically between 400 MPa and 700 MPa, when the coil and powder are pressed into shape during the manufacturing process, the high pressure on the powder can puncture the coil's paint film, increasing the risk of short circuits between the coil's internal wiring. This is particularly serious with high-frequency inductors, where the risk of short circuits is even higher. Summary of the Invention

[0005] The present application provides an inductor molding method and an inductor, which can enable the magnet of the inductor to be molded in a nearly pressure-free state without damaging the paint film of the coil, avoiding the risk of short circuit of the inductor, improving the safety and reliability of the inductor, and having a wider range of applications.

[0006] An embodiment of the present application provides a method for forming an inductor, comprising:

[0007] Provide magnetic glue and coils;

[0008] Place the coil into a forming mold, fill the magnetic glue to cover the coil, and heat to form a magnet;

[0009] heating and baking the formed magnet;

[0010] The two terminals of the coil are bent and formed so as to be attached to the magnet to form electrodes.

[0011] In one embodiment, the step of placing the coil into a molding die, filling the magnetic glue to cover the coil, and heating to form a magnet includes:

[0012] Placing the coil in the cavity of the molding die, placing the upper mold cover of the molding die on the lower mold of the molding die, and fixing the two terminals;

[0013] Providing the magnetic glue to the loading position of the molding die, and heating the magnetic glue at the loading position to soften the magnetic glue into a magnetic glue fluid;

[0014] injecting the magnetic adhesive fluid into the mold cavity through the injection channel of the molding die, so that the magnetic adhesive fluid covers the coil and fills the mold cavity;

[0015] The magnetic colloid fluid in the mold cavity is heated to solidify the magnetic colloid fluid and form the magnet.

[0016] In one embodiment, the temperature for heating the magnetic adhesive at the loading position is T1, the time is t1, 80° C. ≤ T1 ≤ 120° C., 1 min ≤ t1 ≤ 3 min.

[0017] In one embodiment, the temperature of the magnetic adhesive in the mold cavity is T2, the time is t2, 160° C. ≤ T2 ≤ 180° C., 1 min ≤ t2 ≤ 3 min.

[0018] In one embodiment, the magnetic glue includes magnetic powder and colloid, and the colloid is coated on the magnetic powder.

[0019] In one embodiment, the particle size of the magnetic powder is A, the initial magnetic permeability of the magnetic powder is UI, 60 mesh ≤ A ≤ 300 mesh; 20 ≤ UI ≤ 40.

[0020] In one embodiment, the magnetic powder is at least one of alloy iron powder, carbonyl iron powder, amorphous powder, and nanocrystalline powder.

[0021] In one embodiment, the colloid includes thermosetting glue, thermoplastic glue and lubricant.

[0022] In one embodiment, the temperature for heating and baking the molded magnet is T3, the time is t3, 160° C.≤T3≤180° C., 60 min≤t2≤400 min.

[0023] An embodiment of the present application further provides an inductor, which is manufactured using the inductor forming method described in any of the above schemes. The inductor includes a magnet, a coil and two terminals. The coil is arranged in the magnet, and the two terminals are connected to leads at both ends of the coil. The terminals are inserted into the magnet and are arranged in contact with the magnet. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] FIG1 is a schematic diagram of a first embodiment of an inductor forming method according to an embodiment of the present application;

[0025] FIG2 is a second schematic diagram of a forming method of an inductor provided in a specific embodiment of the present application;

[0026] FIG3 is a cross-sectional view of a molding die used in a molding method for an inductor according to a specific embodiment of the present application;

[0027] FIG4 is a comparison table of inductor performance provided in a specific embodiment of the present application.

[0028] In the picture:

[0029] 100, magnetic glue; 10, mold cavity; 20, upper mold; 30, lower mold. DETAILED DESCRIPTION

[0030] The present application is described below in conjunction with the accompanying drawings and embodiments. The embodiments described herein are intended only to explain the present application and are not intended to limit the present application. For ease of description, the accompanying drawings only show portions related to the present application, not all structures.

[0031] In the description of this application, unless otherwise specified or limited, the terms "connected," "connect," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and can refer to internal communication between two components or interaction between two components. A person of ordinary skill in the art will be able to understand the meaning of the above terms in this application according to the circumstances.

[0032] In this application, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Moreover, a first feature being "above," "above," and "above" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicates that the first feature's horizontal height is higher than the second feature's horizontal height. A first feature being "below," "below," and "below" a second feature includes the first feature being directly below and obliquely below the second feature, or simply indicates that the first feature's horizontal height is lower than the second feature's horizontal height.

[0033] In the description of this embodiment, the terms "upper," "lower," "right," and other orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely for ease of description and simplified operation. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first" and "second" are used solely for descriptive purposes and have no special meanings.

[0034] This embodiment provides a method for forming an inductor, which can realize the molding of the magnet of the inductor in a nearly pressure-free state without damaging the paint film of the coil, avoiding the risk of short circuit of the inductor, improving the safety and reliability of the inductor, and having a wider range of applications.

[0035] Referring to Figures 1 to 3, the inductor forming method includes the following steps:

[0036] S10, preparation: providing the magnetic glue 100 and the coil; that is, through this step, the magnetic glue 100 and the coil are formed, and the prerequisite preparation is made for the subsequent inductor forming.

[0037] The preparation of the magnetic colloid 100 includes step S11 , providing colloid and magnetic powder, and coating the colloid on the magnetic powder of a certain mesh size to form the magnetic colloid 100 .

[0038] Optionally, the magnetic glue 100 includes magnetic powder and colloid, and the colloid is coated on the magnetic powder, that is, the magnetic powder is made into magnetic powder according to a certain mesh size through the colloid, which also makes the magnetic glue 100 have certain adhesion and fluidity.

[0039] Optionally, the particle size of the magnetic powder is A, the initial magnetic permeability of the magnetic powder is UI, 60 mesh ≤ A ≤ 300 mesh; 20 ≤ UI ≤ 40. By selecting the magnetic powder with the above particle size and initial magnetic permeability, the magnetic glue 100 required for inductor molding can be formed by wrapping the colloid on the outside.

[0040] For example, A can be 60 mesh, 70 mesh, 80 mesh, 90 mesh, 100 mesh, 120 mesh, 150 mesh, 180 mesh, 200 mesh, 220 mesh, 250 mesh, or 280 mesh. For example, the UI value can be 20, 25, 30, 35, or 40.

[0041] Optionally, the magnetic powder is at least one of alloy iron powder, carbonyl iron powder, amorphous powder, and nanocrystalline powder. The magnetic powder can be selected from one or more combinations of the above powder materials, and can be adaptively selected according to actual needs, which is not limited here.

[0042] Optionally, the above-mentioned colloid includes thermosetting glue, thermoplastic glue and lubricant, which is made by mixing the above-mentioned multiple materials. Thermosetting glue is suitable for fixing the magnetic glue 100. The addition of thermoplastic glue and lubricant makes the colloid become fluid when heated to a certain temperature range, thereby facilitating the flow of the magnetic glue 100.

[0043] The preparation of the coil comprises the following steps:

[0044] S12. Provide copper wire and wind it into a hollow coil through a center column. Specifically, the copper wire is wound along the center column into a spring-like shape. Lead wires extend from both ends of the coil, and the diameter of the center column is the diameter of the hollow center of the coil.

[0045] Optionally, the copper wire may be a round copper wire or a flat copper wire, which is not limited here.

[0046] Optionally, the cross-sectional shape of the central column may be circular, elliptical or waist-shaped, which is not limited here.

[0047] S13, Spot Welding: Provide terminals, place multiple coils side by side along the same winding direction, and spot weld the leads at both ends of the coils to the two terminals. This means that by fixing the leads at both ends of the coils to the two terminals, the positive and negative terminals of the coil assembly are determined, forming the positive and negative electrodes.

[0048] S20, Molding: The coil is placed in a molding die, filled with magnetic glue 100 to cover the coil, and heated to form a magnet. Utilizing the fluid and adhesive properties of magnetic glue 100, the coil is filled with magnetic glue 100 and solidified to form a magnet, completing the basic molding of the inductor.

[0049] The above step S20 includes the following steps:

[0050] S21. Place the coil in the mold cavity 10 of the molding mold, cover the upper mold 20 of the molding mold on the lower mold 30 of the molding mold, and fix the two terminals; the coil can be positioned and placed, and it is ensured that the terminals are not completely covered in the mold cavity 10, thereby ensuring the electrical connection between the terminals and the outside.

[0051] S22, providing the magnetic glue 100 to the loading position of the molding die, heating the magnetic glue 100 at the loading position to soften the magnetic glue 100 into a magnetic glue fluid; that is, heating the magnetic glue 100 to a certain temperature so that the magnetic glue 100 becomes fluid, thereby facilitating the magnetic glue 100 to flow into the mold cavity 10 for molding.

[0052] Optionally, the temperature for heating the magnetic glue 100 at the loading position in step S22 is T1, the time is t1, 80°C≤T1≤120°C, 1min≤t1≤3min, and the magnetic glue 100 can be softened by heating at T1 for t1 time.

[0053] For example, the TI can be 80° C., 90° C., 100° C., 110° C., or 120° C. For example, the t1 can be 1 min, 2 min, or 3 min.

[0054] S23, injecting magnetic glue fluid into the mold cavity 10 through the injection channel of the forming mold, so that the magnetic glue fluid covers the coil and fills the mold cavity 10; so that the magnetic glue 100 is provided around the coil, and the forming of a flowing magnet can be achieved.

[0055] S24, heating the magnetic glue fluid in the mold cavity 10 to solidify the magnetic glue fluid into a magnet. The heating can achieve preliminary solidification of the magnet, thereby achieving preliminary shaping of the inductor.

[0056] Optionally, in step S24, the temperature of the magnetic adhesive fluid in the mold cavity 10 is T2, the time is t2, 160°C≤T2≤180°C, 1min≤t2≤3min. By heating at T2 for t2, the magnetic adhesive 100 fluid can be initially solidified.

[0057] Exemplarily, the T2 can be 160° C., 170° C., or 180° C. Exemplarily, the t2 can be 1 min, 2 min, or 3 min.

[0058] S30, baking: heating and baking the formed magnet to achieve the solidification of the magnet and ensure the formation of the magnet. That is, at this temperature, the thermosetting glue in the colloid undergoes a chemical reaction, thereby solidifying the magnet and preventing it from becoming fluid when heated, thereby ensuring the stability of the inductor after formation.

[0059] Optionally, in step S30 , the temperature for heating and baking the formed magnet is T3, the time is t3, 160° C. ≤ T3 ≤ 180° C., 60 min ≤ t2 ≤ 400 min. By heating at T3 for t3, the magnetic glue 100 fluid can be solidified.

[0060] For example, the T3 can be 160° C., 170° C., or 180° C. For example, the t3 can be 60 min, 120 min, 180 min, 240 min, 300 min, 360 min, or 400 min.

[0061] Since the magnetic powder can be made of rust-proof magnetic material or non-rust-proof magnetic material; when the magnetic powder is made of rust-proof magnetic material, it does not need to be insulated; when the magnetic powder is made of non-rust-proof magnetic material, step S35 needs to be performed after the baking in step S30: insulation treatment is performed on the formed magnet.

[0062] Optionally, the insulation treatment is to coat the surface of the molded part with a layer of insulating varnish; the implementation method is not limited here. In this embodiment, the coating of the insulating varnish is achieved by spraying.

[0063] S40: Bending: The two terminals of the coil are bent and formed so that they fit on the magnet to form electrodes. This fixes the positive and negative terminals of the inductor.

[0064] In the inductor forming method of this embodiment, the magnetic adhesive 100 is directly solidified by heating to form a magnet, eliminating the need for pressurized magnetic powder. This allows the inductor to be formed in a near-pressureless state, preventing the paint film of the coil from being punctured and thus avoiding the problem of coil short-circuiting. This improves the safety and reliability of the inductor manufactured using this inductor forming method, allowing it to be used as a high-frequency inductor, expanding its range of applications. Furthermore, the inductor design eliminates the need to reserve space for the coil to expand after compression, increasing the size of the coil and, in turn, the coil size per unit volume of the inductor.

[0065] This embodiment also provides an inductor, which is manufactured using the inductor forming method described in any of the above solutions. This can increase the occupied area of ​​the coil inside the inductor, improve space utilization, and at the same time improve the safety and reliability of the inductor, thereby expanding its scope of application.

[0066] The inductor comprises a magnet, a coil, and two terminals. The coil is positioned within the magnet, and the two terminals are connected to leads at either end of the coil. The terminals penetrate the magnet and are positioned in close contact with it. This inductor molding method increases the area occupied by the coil within the inductor, improving space utilization, while also enhancing the safety and reliability of the inductor and expanding its applicability.

[0067] Referring to Figure 4 below, a comparison is made between the inductors made by the related technical solution and the two inductor forming methods in this embodiment. As can be seen from Figure 4, Example 1 is an inductor made by the related technical solution, the wire diameter of the coil of the inductor is 0.3mm, the diameter of the middle column is 3mm, and the number of coil windings is 35.5 turns. Example 2 is Inductor 1 made by the inductor forming method in this embodiment, the wire diameter of the coil of the inductor is 0.3mm, the diameter of the middle column is 4.4mm, and the number of coil windings is 35.5 turns. Example 3 is Inductor 2 made by the inductor forming method in this embodiment, the wire diameter of the coil of the inductor is 0.36mm, the diameter of the middle column is 4mm, and the number of coil windings is 30.5 turns.

[0068] As can be seen from Figure 4, the inductance, saturation current, and DC resistance of the inductor manufactured in Example 2 using the inductor molding method of this embodiment are all higher than those of Example 1, and the short-circuit probability of the inductors in Examples 2 and 3 is both zero. That is, the performance of the inductor manufactured using the inductor molding method of this embodiment is also improved, while the safety and reliability of the inductor are also improved.

Claims

1. The forming method of the inductor includes: Providing a magnetic glue (100) and a coil; The coil is placed in a forming mold, the magnetic glue (100) is filled in to cover the coil, and the coil is heated to form a magnet; heating and baking the formed magnet; The two terminals of the coil are bent and formed so as to fit the two terminals of the coil onto the magnet to form electrodes.

2. The method for forming an inductor according to claim 1, wherein: The coil is placed in a forming mold, the magnetic glue (100) is filled in to cover the coil, and heated to form a magnet, comprising: The coil is placed in the mold cavity (10) of the molding mold, the upper mold (20) of the molding mold is covered on the lower mold (30) of the molding mold, and the two terminals are fixed; Providing the magnetic glue (100) to the upper material position of the molding die, and heating the magnetic glue (100) at the upper material position to soften the magnetic glue (100) into a magnetic glue fluid; Injecting the magnetic colloid fluid into the mold cavity (10) through the injection channel of the molding die, so that the magnetic colloid fluid covers the coil and fills the mold cavity (10); The magnetic colloid fluid in the mold cavity (10) is heated to solidify the magnetic colloid fluid and form the magnet.

3. The method for forming an inductor according to claim 2, wherein: The temperature when heating the magnetic glue (100) at the loading position is T1, the time is t1, 80°C≤T1≤120°C, 1min≤t1≤3min.

4. The method for forming an inductor according to claim 2, wherein: The temperature when heating the magnetic rubber fluid in the mold cavity (10) is T2, the time is t2, 160°C≤T2≤180°C, 1min≤t2≤3min.

5. The method for forming an inductor according to any one of claims 1 to 4, wherein: The magnetic colloid (100) comprises magnetic powder and colloid, and the colloid is coated on the magnetic powder.

6. The method for forming an inductor according to claim 5, wherein: The particle size of the magnetic powder is A, and the initial magnetic permeability of the magnetic powder is UI, 60 mesh≤A≤300 mesh; 20≤UI≤40.

7. The method for forming an inductor according to claim 5, wherein: The magnetic powder is at least one of alloy iron powder, carbonyl iron powder, amorphous powder and nanocrystalline powder.

8. The method for forming an inductor according to claim 5, wherein: The colloid includes thermosetting glue, thermoplastic glue and lubricant.

9. The method for forming an inductor according to any one of claims 1 to 4, wherein: The temperature for heating and baking the formed magnet is T3, the time is t3, 160°C≤T3≤180°C, 60min≤t2≤400min.

10. An inductor manufactured by the inductor molding method according to any one of claims 1 to 9, the inductor comprising a magnet, a coil and two terminals, the coil is arranged in the magnet, the two terminals are connected to the leads at both ends of the coil, and the terminals are passed through the magnet and are arranged in close contact with the magnet.

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