Inductor and method of manufacturing and use thereof

Abstract

The application provides an inductor and a preparation method and application thereof, and the preparation method comprises the following steps: (1) mixing magnetic powder and glue, performing coating granulation treatment, and then pressing into a T-core; performing semi-curing treatment on the T-core; (2) parallelly winding two wires to form a conductor coil with four lead wires; welding the four lead wires of the conductor coil with a lead frame to obtain a wire combination; sleeving the wire combination on the T-core after the semi-curing treatment in step (1), filling magnetic powder, and then performing cold pressing treatment to obtain a semi-finished inductor; (3) performing hot pressing treatment on the semi-finished inductor in step (2), and then performing post-processing to obtain the inductor. According to the method, the coil deformation of the inductor prepared by the method is small, the saturation characteristic is good, the quality is high, and the method has low requirements on equipment, and can meet the requirements of small-size products.

Description

Technical Field

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

[0002] Currently, there are many types of inductor components on the market, but it is generally difficult to solve the problems of conductor coil deformation, high impedance, and low saturation, and the manufacturing process is complex. For example, existing inductors manufactured using the one-piece molded leadframe process require the wound coil to be soldered onto the conductor electrodes first. The contact impedance generated by soldering, coupled with the lack of positioning protection during molding, causes the coil to deform, further increasing the impedance. This results in the finished product having misaligned edges and low saturation, leading to poor market competitiveness. In addition, the large coil deformation makes it difficult for customers of automotive products with high quality requirements to accept. Another type of one-piece molded inductor uses the T-core process. Although the coil deformation is somewhat improved by the T-core as support, the T-core requires very high strength (because the wire needs to be wound on the central column of the T-core) and precision. Especially as product sizes become smaller, the requirements for equipment precision and powder characteristics (such as sphericity and flowability) will be very high.

[0003] CN202183292U discloses an integrated hot-cold pressing inductor, which is manufactured by general processes such as coil stripping, spot welding and hot-cold pressing. It adopts a coil welding and molding process: when the coil is welded to the terminal, contact resistance is introduced, which causes the DC resistance to increase first. During molding, the coil and the terminal will be deformed, which causes the DC resistance to increase again. Because it cannot be controlled, the impedance distribution will be very large.

[0004] CN108648901A discloses an electronic component and a method for manufacturing an inductor, which is a wire-wound inductor using a T-core process. The process involves first pressing a T-core, then winding wire onto the T-core, and finally processing it through molding and other general processes. Although it uses the T-core process, with the coil wound on the central pillar of the T-core, the coil deformation is small during hot pressing due to the protection of the T-core. However, the T-core requires very high strength (for subsequent winding on the T-core) and precision. Especially as the product size decreases, the requirements for equipment precision and powder characteristics (such as sphericity and flowability) become very high, making it unsuitable for the production of smaller inductors. Summary of the Invention

[0005] The purpose of this invention is to provide an inductor, its preparation method, and its application. The inductor prepared by the method of this invention has small coil deformation, good saturation characteristics, and high quality. Moreover, the method has low equipment requirements and can meet the requirements of small-sized products.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a method for fabricating an inductor, the method comprising the following steps:

[0008] (1) Mix magnetic powder and glue, coat and granulate them, and press them into T-core. Then, perform semi-curing treatment on the T-core.

[0009] (2) Two wires are wound together to form a conductor coil with four leads. The four leads of the conductor coil are welded to the conductor frame to obtain a wire assembly. The wire assembly is placed on the T-core after the semi-curing treatment in step (1), filled with magnetic powder, and then cold-pressed to obtain a semi-finished inductor.

[0010] (3) The semi-finished inductor described in step (2) is subjected to hot pressing treatment, and the inductor is obtained after post-processing.

[0011] In the preparation method of the present invention, steps (1) and (2) are not in any particular order; step (1) can be performed first or step (2) can be performed first.

[0012] This invention uses a simple method to wind two wires together to obtain a coil with four leads. The four leads are then welded to the small feet of the lead frame. These four feet not only fix the position of the coil leads but also improve the coil's centering, enhancing its internal structural stability and significantly improving the inductor's conductivity. Traditional molding processes have fewer lead fixing points, resulting in greater coil deformation and difficulty in centering the coil, which can easily damage its structure. This invention pre-cures the T-core, allowing the surface to harden while the interior remains uncured. This ensures the T-core remains intact when combined with the wires. After cold pressing, hot pressing is performed, reducing coil deformation, ensuring the structural stability and saturation characteristics of the wire assembly, improving the inductor's quality, and preventing the risk of interface cracks.

[0013] Preferably, the magnetic powder in step (1) includes amorphous powder and / or alloy powder, and is more preferably amorphous powder and alloy powder.

[0014] Preferably, the amorphous powder includes any one or a combination of at least two of iron-based amorphous powder, nickel-based amorphous powder, or zirconium-based amorphous powder.

[0015] Preferably, the alloy powder includes any one or a combination of at least two of the following: iron alloy powder, copper alloy powder, nickel alloy powder, cobalt alloy powder, aluminum alloy powder, or titanium alloy powder.

[0016] Preferably, the adhesive includes epoxy resin adhesive.

[0017] Preferably, the mass ratio of the magnetic powder to the adhesive is 100:(1-4), for example: 100:1, 100:1.5, 100:2, 100:3 or 100:4, etc.

[0018] Preferably, the coating granulation process is followed by sieving.

[0019] Preferably, the mesh size of the sieve is 80 to 260 mesh, for example: 80 mesh, 100 mesh, 150 mesh, 200 mesh or 260 mesh, etc.

[0020] Preferably, the pressing in step (1) is performed by drying.

[0021] Preferably, the drying temperature is 50-60°C, for example: 50°C, 52°C, 55°C, 58°C or 60°C.

[0022] Preferably, the drying time is 1 to 2 hours, for example: 1 hour, 1.2 hours, 1.5 hours, 1.8 hours or 2 hours.

[0023] Preferably, the pressing pressure is 60 to 300 MPa, for example: 60 MPa, 80 MPa, 100 MPa, 200 MPa or 300 MPa, etc.

[0024] Preferably, the pressing time is 3 to 8 seconds, for example: 3 seconds, 4 seconds, 5 seconds, 6 seconds or 8 seconds.

[0025] Preferably, the temperature of the semi-curing treatment in step (1) is 200 to 220°C, for example: 200°C, 205°C, 210°C, 215°C or 220°C.

[0026] Preferably, the semi-curing treatment employs a reflow soldering process.

[0027] Preferably, the number of reflow soldering cycles for the semi-curing treatment is 2 to 3.

[0028] Preferably, the material of the two wires in step (2) includes copper.

[0029] Preferably, the diameter of the two conductors is 0.3 to 0.65 mm, for example: 0.3 mm, 0.35 mm, 0.38 mm, 0.4 mm, 0.45 mm, 0.5 mm, 0.55 mm, 0.60 mm or 0.65 mm, and more preferably 0.4 to 0.5 mm.

[0030] It should be noted that the two wires used in this application need to have the same wire diameter so that they can be more tightly connected.

[0031] Preferably, the temperature of the cold pressing process in step (2) is 20 to 30°C, for example: 20°C, 22°C, 25°C, 28°C or 3°C, etc.

[0032] Preferably, the pressure of the cold pressing process is 60 to 300 MPa, for example: 60 MPa, 80 MPa, 100 MPa, 200 MPa or 300 MPa, etc.

[0033] Preferably, the cold pressing time is 1 to 3 minutes, for example: 1 minute, 1.5 minutes, 2 minutes, 2.5 minutes or 3 minutes.

[0034] Preferably, the pressure of the hot pressing process in step (3) is 60 to 300 MPa, for example: 60 MPa, 80 MPa, 100 MPa, 200 MPa or 300 MPa.

[0035] Preferably, the temperature of the hot pressing treatment is 100 to 250°C, for example: 100°C, 120°C, 150°C, 200°C or 250°C.

[0036] Preferably, the hot pressing time is 1 to 3 minutes, for example: 1 minute, 1.5 minutes, 2 minutes, 2.5 minutes or 3 minutes.

[0037] Preferably, the post-processing in step (3) includes grinding and insulation treatment.

[0038] Preferably, the insulation treatment includes spraying an insulating layer onto the inductor surface and curing it.

[0039] Preferably, the thickness of the insulating layer is 8 to 12 μm, for example: 8 μm, 9 μm, 10 μm, 11 μm, or 12 μm.

[0040] In a second aspect, the present invention provides an inductor, which is manufactured by the method described in the first aspect.

[0041] Thirdly, the present invention provides an application of the inductor as described in the second aspect, wherein the inductor is used in electronic products.

[0042] Compared with the prior art, the present invention has the following beneficial effects:

[0043] (1) The inductor produced by the method of the present invention has small coil deformation, good saturation characteristics and high quality. Moreover, the method has low equipment requirements and can meet the requirements of small-sized products.

[0044] (2) The inductance obtained by the method of the present invention can reach more than 1.05μH, more than 6.4A of saturation current, and more than 85% of saturation change rate. Attached Figure Description

[0045] Figure 1 This is a schematic diagram of the conductor coil and the conductor frame welded together to form a conductor assembly as described in Embodiments 1-3 of the present invention, where 1-conductor coil, 2-conductor assembly.

[0046] Figure 2 This is a schematic diagram of the T-core obtained in Embodiments 1-3 of the present invention. Detailed Implementation

[0047] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0048] Example 1

[0049] This embodiment provides an inductor, the formulation of which is as follows:

[0050] Iron-silicon powder: alloy powder = 4:6, epoxy resin (PH) glue content 2.2%;

[0051] Two copper wires with a diameter of 0.4 mm are wound together 5.5 times. The specific preparation method includes:

[0052] Weigh out iron-silicon powder, alloy powder, and pH glue according to the specified ratio, mix and granulate, then sieve the granules through a 100-mesh sieve and bake in an oven at 55℃ for 1.5 hours. The granulated powder is then pressed at 200MPa for 4 seconds using a one-time molding machine to form a magnetic T-core (e.g., ...). Figure 2 As shown), the pressed T-core is cured by reflow soldering at 210℃ twice;

[0053] (2) Two copper wires are wound together to form a conductor coil with four leads. The four leads of the conductor coil are then welded to a conductor frame to obtain a conductor assembly (e.g., Figure 1 As shown, where 1 is a conductor coil and 2 is a wire assembly, the wire assembly is placed on the T-core after the semi-cured treatment in step (1), magnetic powder is filled in, and then cold-pressed at 25°C and 200MPa for 2 minutes to obtain a semi-finished inductor.

[0054] (3) The semi-finished inductor described in step (2) is hot-pressed at 175°C and 200MPa for 1.5 minutes, and then an insulating layer with a thickness of 12μm is sprayed onto the surface of the baked inductor and cured; the bending process includes bending the lead frame extending from the inductor with a bending machine to obtain the inductor.

[0055] Example 2

[0056] This embodiment provides an inductor, the formulation of which is as follows:

[0057] Iron-silicon powder: alloy powder = 5:5, pH glue content 2.2%;

[0058] Two copper wires with a diameter of 0.4 mm are wound together 5.5 times. The specific preparation method includes:

[0059] Weigh out iron-silicon powder, alloy powder, and pH glue according to the specified ratio, mix and granulate, then sieve the granules through a 100-mesh sieve and bake in an oven at 55℃ for 1.5 hours. The granulated powder is then pressed at 200MPa for 4 seconds using a one-time molding machine to form a magnetic T-core (e.g., ...). Figure 2 As shown), the pressed T-core is cured by reflow soldering at 210℃ twice;

[0060] (2) Two copper wires are wound together to form a conductor coil with four leads. The four leads of the conductor coil are then welded to a conductor frame to obtain a conductor assembly (e.g., Figure 1 As shown, where 1 is a conductor coil and 2 is a wire assembly, the wire assembly is placed on the T-core after the semi-cured treatment in step (1), magnetic powder is filled in, and then cold-pressed at 25°C and 200MPa for 2 minutes to obtain a semi-finished inductor.

[0061] (3) The semi-finished inductor described in step (2) is hot-pressed at 175°C and 200MPa for 1.5 minutes, and then an insulating layer with a thickness of 12μm is sprayed onto the surface of the baked inductor and cured; the bending process includes bending the lead frame extending from the inductor with a bending machine to obtain the inductor.

[0062] Example 3

[0063] This embodiment provides an inductor, the formulation of which is as follows:

[0064] Iron-silicon powder: alloy powder = 6:4, pH glue content 2.4%;

[0065] Two copper wires with a diameter of 0.4 mm are wound together 5.5 times. The specific preparation method includes:

[0066] Weigh out iron-silicon powder, alloy powder, and pH glue according to the specified ratio, mix and granulate, then sieve the granules through a 100-mesh sieve and bake in an oven at 55℃ for 1.5 hours. The granulated powder is then pressed at 200MPa for 4 seconds using a one-time molding machine to form a magnetic T-core (e.g., ...). Figure 2 As shown), the pressed T-core is cured by reflow soldering at 210℃ twice;

[0067] (2) Two copper wires are wound together to form a conductor coil with four leads. The four leads of the conductor coil are then welded to a conductor frame to obtain a conductor assembly (e.g., Figure 1 As shown, where 1 is a conductor coil and 2 is a wire assembly, the wire assembly is placed on the T-core after the semi-cured treatment in step (1), magnetic powder is filled in, and then cold-pressed at 25°C and 200MPa for 2 minutes to obtain a semi-finished inductor.

[0068] (3) The semi-finished inductor described in step (2) is hot-pressed at 175°C and 200MPa for 1.5 minutes, and then an insulating layer with a thickness of 12μm is sprayed onto the surface of the baked inductor and cured; the bending process includes bending the lead frame extending from the inductor with a bending machine to obtain the inductor.

[0069] Comparative Example 1

[0070] The only difference between this comparative example and Example 1 is that the cold pressing process is replaced with molding at 80°C, while the other conditions and parameters are exactly the same as in Example 1.

[0071] Comparative Example 2

[0072] The only difference between this comparative example and Example 1 is that only one copper wire is used to make the coil, and two leads are soldered on. All other conditions and parameters are exactly the same as in Example 1.

[0073] Comparative Example 3

[0074] The only difference between this comparative example and Example 1 is that T-core is not used; all other conditions and parameters are exactly the same as in Example 1.

[0075] Performance testing:

[0076] The characteristics of the inductors prepared in Examples 1-3 and Comparative Examples 1-3 were tested, and the test results are shown in Table 1:

[0077] Table 1

[0078] Example 1 1.05 6.5 85 Example 2 1.06 6.4 88 Example 3 1.05 6.5 88.5 Comparative Example 1 1.04 6.4 84 Comparative Example 2 1.04 5.8 78 Comparative Example 3 1.04 5.5 72

[0079] As can be seen from Table 1, and from Examples 1-3, the inductance of the inductor produced by the method of the present invention can reach more than 1.05 μH, the saturation current can reach more than 6.4 A, and the saturation change rate can reach more than 85%.

[0080] As can be seen from the comparison between Example 1 and Comparative Example 1, the present invention adopts the cold-pressed core filling process. On the one hand, the coil is placed on the cold-pressed core, which plays a role in further stabilizing the coil. On the other hand, the coil is supported by the central column, which enhances the centrality of the coil and greatly improves the inductance saturation.

[0081] As can be seen from the comparison between Example 1 and Comparative Example 2, the present invention uses two wires to make a conductor coil including four leads. The four leads are fixed on the four small feet of the conductor frame. The leads are fixed, and the coil is also relatively fixed, which reduces the coil deformation, reduces the risk of short circuit, and greatly improves the inductance performance.

[0082] As can be seen from the comparison between Example 1 and Comparative Example 3, on the one hand, the coil is placed on the cold-pressed core, which plays a role in further stabilizing the coil; on the other hand, the coil is supported by the central column, which enhances the neutrality of the coil and greatly improves the inductance saturation.

[0083] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for preparing an inductor, characterized in that, The preparation method includes the following steps: (1) The magnetic powder and glue are mixed and coated and granulated, and then pressed into T-core. The T-core is subjected to semi-curing treatment. After the semi-curing treatment, the surface of the T-core is cured, but the inside is not cured. The temperature of the semi-curing treatment is 200~220℃. The semi-curing treatment adopts the reflow soldering process. The number of reflow soldering times for the semi-curing treatment is 2~3. (2) Two wires are wound together to form a conductor coil with four leads. The four leads of the conductor coil are welded to the wire frame to obtain a wire assembly. The wire assembly is placed on the T-core after the semi-curing treatment in step (1). After filling with magnetic powder, it is cold-pressed to obtain a semi-finished inductor. The temperature of the cold pressing treatment is 20~30℃. (3) The semi-finished inductor described in step (2) is subjected to hot pressing treatment, and the inductor is obtained after post-processing.

2. The preparation method according to claim 1, characterized in that, The magnetic powder in step (1) includes amorphous powder and / or alloy powder.

3. The preparation method according to claim 2, characterized in that, The magnetic powder in step (1) is amorphous powder and alloy powder.

4. The preparation method according to claim 2, characterized in that, The amorphous powder includes any one or a combination of at least two of iron-based amorphous powder, nickel-based amorphous powder, or zirconium-based amorphous powder.

5. The preparation method according to claim 2, characterized in that, The alloy powder includes any one or a combination of at least two of the following: iron alloy powder, copper alloy powder, nickel alloy powder, cobalt alloy powder, aluminum alloy powder, or titanium alloy powder.

6. The preparation method according to claim 1, characterized in that, The adhesive includes epoxy resin adhesive.

7. The preparation method according to claim 1, characterized in that, The mass ratio of the magnetic powder to the adhesive is 100:(1~4).

8. The preparation method according to claim 1, characterized in that, The coating and granulation process is followed by sieving.

9. The preparation method according to claim 8, characterized in that, The sieve mesh size is 80~260 mesh.

10. The preparation method according to claim 1, characterized in that, The step (1) involves drying the material before pressing.

11. The preparation method according to claim 10, characterized in that, The drying temperature is 50~60℃.

12. The preparation method according to claim 10, characterized in that, The drying time is 1 to 2 hours.

13. The preparation method according to claim 1, characterized in that, The pressing pressure is 60~300MPa.

14. The preparation method according to claim 1, characterized in that, The pressing time is 3-8 seconds.

15. The preparation method according to claim 1, characterized in that, The material of the two wires in step (2) includes copper.

16. The preparation method according to claim 1, characterized in that, The diameter of the two wires in step (2) is 0.3~0.65mm.

17. The preparation method according to claim 16, characterized in that, The diameter of the two wires in step (2) is 0.4~0.5mm.

18. The preparation method according to claim 1, characterized in that, The pressure of the cold pressing process in step (2) is 60~300MPa.

19. The preparation method according to claim 1, characterized in that, The cold pressing process in step (2) takes 1 to 3 minutes.

20. The preparation method according to claim 1, characterized in that, The pressure of the hot pressing process in step (3) is 60~300MPa.

21. The preparation method according to claim 1, characterized in that, The temperature of the hot pressing process in step (3) is 100~250℃.

22. The preparation method according to claim 1, characterized in that, The hot pressing process in step (3) takes 1 to 3 minutes.

23. The preparation method according to claim 1, characterized in that, The post-processing in step (3) includes grinding and insulation.

24. The preparation method according to claim 23, characterized in that, The insulation treatment in step (3) includes spraying an insulating layer onto the surface of the inductor and curing it.

25. The preparation method according to claim 24, characterized in that, The thickness of the insulating layer in step (3) is 8~12μm.

26. An inductor, characterized in that, The inductor is produced by the method described in any one of claims 1-25.

27. An application of the inductor as described in claim 26, characterized in that, The inductor is used in electronic products.

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