Monolithically integrated inductor and method of manufacturing the same

Abstract

This invention discloses a molded inductor and its manufacturing method. The molded inductor includes a core, a coil, a residual magnet, and a disk. The core and disk are made of a composite material composed of iron-based alloys. The coil is wound around the core and bent and fastened to the bottom of the disk to form a bottom electrode. The residual magnet is composed of a mixed powder of iron-based alloys, iron-based amorphous nanocrystals, and carbonyl iron powder, covering the core and coil. An insulating and anti-rust layer is attached to the residual magnet, which is a composite coating composed of phenyl oxy resin, phenolic epoxy resin, and silicon micropowder. This invention can reduce inductor losses and improve the conversion efficiency of power circuits using the inductor of this invention.

Description

Technical Field

[0001] This invention relates to the field of electronic equipment technology, specifically to a wire-wound type integrally molded inductor. Background Technology

[0002] Against the backdrop of ever-increasing demands for energy conservation and environmental protection across the entire electronics industry, improving power supply efficiency is a key development direction. High-efficiency power supplies reduce energy loss, lower equipment operating costs, and help reduce heat generation. One of the biggest sources of loss in power supplies is inductance. Currently, the mainstream inductors for high-current circuits are integrally molded inductors made of alloy composite materials. However, because their coils need to be pressed together with the magnet, excessive pressure cannot be used, leading to deformation of the copper wire, increasing its resistance. Simultaneously, the presence of significant stress results in high residual losses and a risk of short circuits.

[0003] Therefore, it is essential to conduct composition, process, and structural design on integrally molded inductor alloy powder to improve the material's performance, maintain low loss at high frequencies, and also have low loss at high power. Thus, it is necessary to develop new high-frequency, high-current, low-loss composite materials and their integrally molded inductor technology. Summary of the Invention

[0004] The present invention solves the above problems by controlling the material composition and structure.

[0005] The technical means adopted in this invention is to provide a molded inductor, which includes:

[0006] The core is made of a composite material composed of iron-based alloys, including silicon (Si), aluminum (Al) and chromium (Cr);

[0007] A coil, which is wound around the core post;

[0008] A disk, made of a composite material composed of an iron-based alloy, is disposed at the bottom of the core post, and the coil is bent and fastened to the bottom of the disk to form a bottom electrode;

[0009] A residual magnet, which covers the core and the coil and exposes the bottom electrode, is composed of a mixture of iron-based alloys, iron-based amorphous nanocrystals, and carbonyl iron powder.

[0010] An insulating and rust-proof layer is applied to the surface of the remaining magnet. The material of the insulating and rust-proof layer is a composite coating composed of phenyl oxy resin, phenolic epoxy resin, and silica powder.

[0011] Furthermore, the present invention also provides a method for manufacturing the aforementioned inductor, comprising the following steps: providing the core post; winding the coil around the core post; placing the disk at the bottom of the core post, and the coil forming the bottom electrode by bending and fastening it to the bottom of the disk, wherein the core post, the coil, and the bottom electrode constitute the winding; covering the remaining magnet with the winding; and providing the insulating and rust-proof layer on the remaining magnet.

[0012] The advantages of this invention lie in the control of material composition and structure. Specifically, the Si in the core material forms an insulating layer within the metal crystal, reducing internal eddy currents. Simultaneously, the insulating layer enriched with Al and Cr on the surface of the material particles formed at high temperatures further reduces eddy currents. Furthermore, the high Fe content maintains high permeability. This results in a material with low eddy current losses. The increased permeability of the core allows for the use of copper wire with lower resistance to achieve the same inductance value, thereby reducing inductor losses. Additionally, the residual magnet, through a combination of nanocrystals and ultrafine alloys, further reduces eddy current losses at high frequencies, thereby reducing inductor losses and improving the conversion efficiency of power circuits using the inductor of this invention.

[0013] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the present invention. Attached Figure Description

[0014] Figure 1 This is a three-dimensional view of the inductor of the present invention;

[0015] Figure 2 This is a perspective view of some components of the inductor of the present invention;

[0016] Figure 3 This is a perspective view of some components of the inductor of the present invention.

[0017] Figure 4 This is a cross-sectional view of the inductor of the present invention;

[0018] Figure 5 This is a flowchart of the method for manufacturing the inductor according to the present invention.

[0019] In the attached figures, the following labels are used:

[0020] 1: Core

[0021] 2: Coil

[0022] 3: Residual magnets

[0023] 4: Bottom electrode

[0024] 5: Disk

[0025] 6: Insulating and rust-proof layer Detailed Implementation

[0026] The following, in conjunction with the accompanying drawings and embodiments of the invention, further illustrates the technical means employed by the invention to achieve its intended purpose. The drawings have been simplified for illustrative purposes only, and the structure or method of the invention is explained by describing the relationship between the elements and components. Therefore, the elements shown in the drawings are not presented in actual quantity, shape, size, or proportion. The size or proportion has been enlarged or simplified to provide a better illustration. The actual quantity, shape, or proportion has been selectively designed and configured, and the detailed element layout may be more complex.

[0027] Please see Figures 1 to 5As shown, the method for preparing the integrally molded inductor of the present invention includes the following steps: providing a core post 1 (S10); winding a coil 2 around the core post 1 (S20); placing a disk 5 at the bottom of the core post 1, and forming a bottom electrode 4 by bending and fastening the coil 2 to the bottom of the disk 5 (S30), wherein the core post 1, the coil 2, and the bottom electrode 4 constitute a winding; covering the winding with a residual magnet 3 and exposing the bottom electrode 4 (S40); and providing an insulating and rust-proof layer 6 on the residual magnet 3 (S50). The core post 1 occupies 20 vol% to 50 vol% of the volume of the residual magnet 3. The materials of the core post 1 and the disk 5 of the inductor are composite materials composed of iron (Fe)-based alloys. Its material composition is 92.1-96.43 wt% Fe, 3.5-7.5 wt% silicon (Si), 0.01-0.1 wt% boron (B), 0.01-0.1 wt% aluminum (Al), and 0.05-0.2 wt% chromium (Cr). The particle size of the constituent materials is 5-53 μm, and the surface of the particles has a composite oxide layer of silicon oxide, iron oxide, and chromium oxide of 10-100 nm. The height of the core post 1 is 60%-90% of the inductor height. The residual magnet 3 of the inductor is composed of a mixed powder of iron-based alloy, iron-based amorphous nanocrystals, and carbonyl iron powder. The composition can be a mixture of a main material of 89.7-94.97 wt% Fe, 3.0-5.5 wt% Si, 2.0-4.5 wt% B, 0.01-0.1 wt% phosphorus (P), 0.01-0.1 wt% copper (Cu), and 0.01-0.1 wt% nickel (Ni) with a 3-5 μm iron-based alloy. The iron-based alloy consists of 92.1-96.43 wt% Fe, 3.5-7.5 wt% Si, 0.01-0.1 wt% B, and 0.01-0.1 wt% P. The nanocrystal material accounts for 60-80 wt% of the powder weight, and the iron-based alloy accounts for 20-40 wt% of the powder weight. The nanocrystalline surface has two coating layers. The first layer is a mixed layer of oxides such as alumina and silicon oxide, with a thickness of 8–15 nm. The second layer is composed of organic resin, specifically a mixed coating layer of epoxy resin and silicone resin. The epoxy resin has a softening temperature of less than 100℃, while the silicone resin has a thermal decomposition temperature greater than 300℃. The coating layer thickness is 100–200 nm, and the mass ratio of epoxy resin to silicone resin is 1:1 to 3:1. The iron-based alloy surface has a single coating layer with a thickness of 50–150 nm. This coating layer is a mixture of phenolic resin and silicone resin, with the phenolic resin having a softening temperature of less than 100℃ and the silicone resin having a thermal decomposition temperature greater than 300℃. The mass ratio of phenolic resin to silicone resin is 1:1 to 3:1.An insulating and anti-rust layer 6 is attached to the surface of the inductor. The insulating and anti-rust layer 6 is a composite coating composed of phenyl oxy resin, phenolic epoxy resin, and silicon micro powder. The coating thickness is 10-30 μm. Phenoxy resin accounts for 50 wt%-80 wt% of the insulating layer material and has a molecular weight greater than 8000. Phenolic epoxy resin accounts for 10 wt%-30 wt% of the insulating layer material and has a glass transition temperature greater than 150℃. Silicon micro powder accounts for 10 wt%-20 wt% of the insulating layer material and has a particle size of 8-20 nm.

[0028] The technical solutions in the embodiments of the present invention will be clearly and completely described below. The described embodiments are only some embodiments of the present invention, and not all embodiments.

[0029] Example 1:

[0030] The integrally molded inductor of the present invention comprises a core post 1, a coil 2, a residual magnet 3, and a disk 5. The coil 2 is wound around the core post 1 of the magnetic core and is bent and fastened to the bottom of the disk 5 to form a bottom electrode 4. The core post 1 occupies 50 vol% of the volume of the residual magnet 3. The core post 1 and the disk 5 of the inductor are made of a composite material composed of an iron-based alloy. Its material composition is 92.1 wt% Fe, 7.5 wt% Si, 0.1 wt% B, 0.1 wt% Al, and 0.2 wt% Cr. The particle size of the constituent materials is 5-53 μm, and the surface of the particles has a 10 nm composite oxide layer of silicon oxide, iron oxide, and chromium oxide. The height of the core post 1 is 90% of the height of the inductor. The residual magnet 3 of the inductor is composed of a main material consisting of 94.97 wt% Fe, 3.0 wt% Si, 2.0 wt% B, 0.01 wt% P, 0.01 wt% Cu, and 0.01 wt% Ni, mixed with a 5 μm iron-based alloy. The iron-based alloy consists of 96.43 wt% Fe, 3.5 wt% Si, 0.01 wt% B, and 0.01 wt% P. The nanocrystalline material accounts for 60 wt% of the powder weight, and the iron-based alloy accounts for 40 wt% of the powder weight. The nanocrystalline surface has two coating layers: the first layer is a mixed layer of alumina and silicon oxide with a thickness of 15 nm; the second layer is composed of an organic resin, specifically a mixed coating layer of epoxy resin and silicone resin. The epoxy resin has a softening temperature of 70 °C, and the silicone resin has a thermal decomposition temperature of 330 °C. The coating layer thickness is 100 nm, and the mass ratio of epoxy resin to silicone resin is 1:1. The iron-based alloy surface has a coating layer with a thickness of 50 nm. This coating layer is a mixture of phenolic resin and silicone resin. The phenolic resin has a softening temperature of 80℃, and the silicone resin has a thermal decomposition temperature of 330℃. The mass ratio of phenolic resin to silicone resin is 1:1. An insulating and anti-rust layer 6 is attached to the inductor surface. This insulating and anti-rust layer 6 is a composite coating composed of phenyloxy resin, phenolic epoxy resin, and silica powder. The coating thickness is 30 μm. Phenoxy resin accounts for 50 wt% of the insulating layer material, with a molecular weight of 8700. Phenoxy epoxy resin accounts for 30 wt% of the insulating layer material, with a glass transition temperature of 160℃. Silica powder accounts for 20 wt% of the insulating layer material, with a particle size of 20 nm.

[0031] Example 2:

[0032] The integrally molded inductor of the present invention comprises a core post 1, a coil 2, a residual magnet 3, and a disk 5. The coil 2 is wound around the core post 1 of the magnetic core and is bent and fastened to the bottom of the disk 5 to form a bottom electrode 4. The core post 1 occupies 20 vol% of the volume of the residual magnet 3. The core post 1 and the disk 5 of the inductor are made of a composite material composed of an iron-based alloy. Its material composition is 96.43 wt% Fe, 3.5 wt% Si, 0.01 wt% B, 0.01 wt% Al, and 0.05 wt% Cr. The particle size of the constituent materials is 5-53 μm, and the surface of the particles has a 100 nm composite oxide layer of silicon oxide, iron oxide, and chromium oxide. The height of the core post 1 is 60% of the height of the inductor. The residual magnet 3 of the inductor is composed of a main material consisting of 89.7 wt% Fe, 5.5 wt% Si, 4.5 wt% B, 0.1 wt% P, 0.1 wt% Cu, and 0.1 wt% Ni, mixed with a 3 μm iron-based alloy. The iron-based alloy consists of 92.1 wt% Fe, 7.5 wt% Si, 0.1 wt% B, and 0.1 wt% P. Nanocrystalline material accounts for 80 wt% of the powder weight, and the iron-based alloy accounts for 20 wt% of the powder weight. The nanocrystalline surface has two coating layers: the first layer is a mixed layer of oxides such as alumina and chromium oxide, with a thickness of 8 nm; the second layer is composed of organic resin, specifically a mixed coating layer of epoxy resin and silicone resin. The epoxy resin has a softening temperature of 60°C, and the silicone resin has a thermal decomposition temperature of 360°C. The coating layer thickness is 200 nm, and the mass ratio of epoxy resin to silicone resin is 3:1. The iron-based alloy surface has a coating layer with a thickness of 150 nm. This coating layer is a mixture of phenolic resin and silicone resin. The phenolic resin has a softening temperature of less than 65℃, while the silicone resin has a thermal decomposition temperature of 360℃. The mass ratio of phenolic resin to silicone resin is 3:1. An insulating and anti-rust layer 6 is attached to the inductor surface. This insulating and anti-rust layer 6 is a composite coating composed of phenyloxy resin, phenolic epoxy resin, and silica powder. The coating thickness is ~30 μm. Phenoxy resin accounts for 80 wt% of the insulating layer material, with a molecular weight of 9000. Phenoxy epoxy resin accounts for 10 wt% of the insulating layer material, with a glass transition temperature of 170℃. Silica powder accounts for 10 wt% of the insulating layer material, with a particle size of 8 nm.

[0033] Example 3:

[0034] The integrally molded inductor of the present invention comprises a core post 1, a coil 2, a residual magnet 3, and a disk 5. The coil 2 is wound around the core post 1 of the magnetic core and is bent and fastened to the bottom of the disk 5 to form a bottom electrode 4. The core post 1 occupies 20 vol% to 50 vol% of the volume of the residual magnet 3. The core post 1 and the disk 5 of the inductor are made of a composite material composed of an iron-based alloy. Its material composition is 94.35 wt% Fe, 5.5 wt% Si, 0.05 wt% B, 0.05 wt% Al, and 0.15 wt% Cr. The particle size of the constituent materials is 5 to 53 μm, and the surface of the particles has a 50 nm composite oxide layer of silicon oxide, iron oxide, and chromium oxide. The height of the core post 1 is 75% of the height of the inductor. The residual magnet 3 of the inductor is composed of a main material consisting of 91.75 wt% Fe, 4.7 wt% Si, 3.4 wt% B, 0.05 wt% P, 0.05 wt% Cu, and 0.05 wt% Ni, mixed with a 4 μm iron-based alloy. The iron-based alloy consists of 93.8 wt% Fe, 6.1 wt% Si, 0.05 wt% B, and 0.05 wt% P. The nanocrystalline material accounts for 70 wt% of the powder weight, and the iron-based alloy accounts for 30 wt% of the powder weight. The nanocrystalline surface has two coating layers: the first layer is a mixed layer of oxides such as alumina and silicon oxide, with a thickness of 12 nm; the second layer is composed of an organic resin, specifically a mixed coating layer of epoxy resin and silicone resin. The epoxy resin has a softening temperature of 80℃, and the silicone resin has a thermal decomposition temperature of 370℃. The coating layer thickness is 150 nm, and the mass ratio of epoxy resin to silicone resin is 2:1. The iron-based alloy surface has a coating layer with a thickness of 90 nm. This coating layer is a mixture of phenolic resin and silicone resin. The phenolic resin has a softening temperature of 80℃, and the silicone resin has a thermal decomposition temperature of 370℃. The mass ratio of phenolic resin to silicone resin is 2:1. An insulating and anti-rust layer 6 is attached to the inductor surface. This insulating and anti-rust layer 6 is a composite coating composed of phenyloxy resin, phenolic epoxy resin, and silica powder. The coating thickness is 20 μm. Phenoxy resin accounts for 70 wt% of the insulating layer material, with a molecular weight of 9000. Phenoxy epoxy resin accounts for 15 wt% of the insulating layer material, with a glass transition temperature of 170℃. Silica powder accounts for 15 wt% of the insulating layer material, with a particle size of 12 nm.

[0035] Comparative Example 1:

[0036] The fabrication method of the integrally molded inductor of Comparative Example 1 includes the following steps: The inductor is composed of an inductor core 1, a coil 2, a residual magnet 3, and a disk 5, wherein the coil 2 is wound around the core 1 of the magnetic core and is bent and fastened to the bottom of the disk 5 to form a bottom electrode 4. The core 1 accounts for 50 vol% of the volume of the residual magnet 3. The materials of the inductor core 1, the disk 5, and the residual magnet 3 are composed of a main material with a composition of 94.97 wt% Fe, 3.0 wt% Si, 2.0 wt% B, 0.01 wt% P, 0.01 wt% Cu, and 0.01 wt% Ni, mixed with a 5 μm iron-based alloy, wherein the iron-based alloy consists of 96.43 wt% Fe, 3.5 wt% Si, 0.01 wt% B, and 0.01 wt% P, wherein the nanocrystalline material accounts for 60 wt% of the powder weight, and the iron-based alloy accounts for 40 wt% of the powder weight. The nanocrystalline surface has two coating layers. The first layer is a mixed layer of alumina and silicon oxide, 15 nm thick. The second layer is composed of an organic resin, specifically a mixed coating layer of epoxy resin and silicone resin. The epoxy resin has a softening temperature of 70°C, and the silicone resin has a thermal decomposition temperature of 330°C. The coating layer is 100 nm thick, and the mass ratio of epoxy resin to silicone resin is 1:1. The iron-based alloy surface has a single coating layer, 50 nm thick, composed of a mixture of phenolic resin and silicone resin. The phenolic resin has a softening temperature of 80°C, and the silicone resin has a thermal decomposition temperature of 330°C. The mass ratio of phenolic resin to silicone resin is also 1:1. An insulating and anti-rust layer 6 is attached to the surface of the inductor. The insulating and anti-rust layer 6 is a composite coating composed of phenyl oxy resin, phenolic epoxy resin and silica powder. The coating thickness is 30 μm. Phenoxy resin accounts for 50 wt% of the insulating layer material and has a molecular weight of 8700. Phenoxy epoxy resin accounts for 30 wt% of the insulating layer material and has a glass transition temperature of 160℃. Silica powder accounts for 20 wt% of the insulating layer material and has a particle size of 20 nm.

[0037] The product's performance was evaluated. The product dimensions were 6.0mm (L) x 6.0mm (W) x 1.8mm (H). A 3260B LCR meter and a thermistor were used to test the inductance of the magnetic ring sample (1V / 1MHz) and the inductance at 100A. A SY8218 was used to test the product loss (1MHz / 1A). Table 1 shows the performance comparison between the example and comparative examples (0420 inductor).

[0038] Test Project Parameter Units Example 1 Example 2 Example 3 Comparative Example 1 L μH 2.21 2.18 2.2 1.76 <![CDATA[L1 (Current = 5A)]]> μH 1.83 1.87 1.85 1.31 Pc (loss) mW 23 25 19 39

[0039] The 0618 inductors prepared in the comparative examples and comparative examples, with the same inductance value, exhibit superior losses compared to the comparative examples. Therefore, they offer a lower power consumption advantage in practical applications, thereby improving the conversion efficiency of the product's application circuits. This demonstrates that component control and structural design are crucial for low-loss inductors.

[0040] The above description is merely an embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above by way of embodiment, it is not intended to limit the present invention. Anyone skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

[0041] Of course, the present invention may have other various embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications should all fall within the protection scope of the claims of the present invention.

Claims

1. An integrally formed inductor, characterized by, It includes: The core is made of a composite material composed of an iron-based alloy, which includes silicon, aluminum and chromium; A coil, which is wound around the core post; A disk, made of a composite material composed of an iron-based alloy, is disposed at the bottom of the core post, and the coil is bent and fastened to the bottom of the disk to form a bottom electrode; A residual magnet, which covers the core and the coil and exposes the bottom electrode, is composed of a mixture of iron-based alloys, iron-based amorphous nanocrystals, and carbonyl iron powder. as well as An insulating and rust-proof layer is applied to the surface of the remaining magnet. The material of the insulating and rust-proof layer is a composite coating composed of phenyl oxy resin, phenolic epoxy resin, and silica powder.

2. The integrally formed inductor of claim 1, wherein, The core column accounts for 20 vol% to 50 vol% of the volume of the remaining magnet.

3. The integrally formed inductor of claim 1, wherein, The core and the disk are made of 92.1–96.43 wt% iron, 3.5–7.5 wt% silicon, 0.01–0.1 wt% boron, 0.01–0.1 wt% aluminum, and 0.05–0.2 wt% chromium. The particle size of the constituent materials is 5–53 μm, and the surface of the particles has a composite oxide layer of silicon oxide, iron oxide, and chromium oxide of 10–100 nm. The height of the core is 60%–90% of the height of the inductor.

4. The integrally formed inductor of claim 1, wherein, The remaining magnet is made of a mixture of 89.7–94.97 wt% iron, 3.0–5.5 wt% silicon, 2.0–4.5 wt% boron, 0.01–0.1 wt% phosphorus, 0.01–0.1 wt% copper, 0.01–0.1 wt% nickel and 3 μm–5 μm iron-based alloy, wherein the iron-based alloy is composed of 92.1–96.43 wt% iron, 3.5–7.5 wt% silicon, 0.01–0.1 wt% boron and 0.01–0.1 wt% phosphorus, wherein the nanocrystalline material accounts for 60 wt%–80 wt% of the powder weight and the iron-based alloy accounts for 20 wt%–40 wt% of the powder weight. The nanocrystal surface has two coating layers. The first layer is a mixed layer containing at least one of alumina or silicon oxide, with a thickness of 8-15 nm. The second layer is a coating layer composed of organic resin, which is a mixed coating layer of epoxy resin and silicone resin. The epoxy resin has a softening temperature of less than 100°C, and the silicone resin has a thermal decomposition temperature of greater than 300°C. The thickness of the organic resin coating layer on the nanocrystal surface is 100-200 nm, wherein the mass ratio of epoxy resin to silicone resin is 1:1 to 3:

1. The iron-based alloy has a coating layer on its surface with a thickness of 50-150 nm. The coating layer on the surface of the iron-based alloy is a mixture of phenolic resin and silicone resin. The phenolic resin has a softening temperature of less than 100°C and the silicone resin has a thermal decomposition temperature of greater than 300°C. The mass ratio of phenolic resin to silicone resin is 1:1 to 3:

1.

5. The integrally formed inductor of claim 1, wherein, The thickness of the insulating and anti-rust layer is 10-30 μm, wherein phenoxy resin accounts for 50 wt%-80 wt% of the insulating layer material, the molecular weight of phenoxy resin is greater than 8000, phenolic epoxy resin accounts for 10 wt%-30 wt% of the insulating layer material, the glass transition temperature of phenolic epoxy resin is greater than 150℃, and silica powder accounts for 10 wt%-20 wt% of the insulating layer material, wherein the particle size of silica powder is 8-20 nm.

6. A method of manufacturing the one-piece inductor of any one of claims 1 to 5, characterized in that, It includes the following steps: Provide this core post; The coil is wound around the core post; The disk is placed at the bottom of the core post, and the coil is bent and fastened to the bottom of the disk to form the bottom electrode, wherein the core post, the coil, and the bottom electrode constitute the winding; The remaining magnet is then wrapped around the winding. The insulating and rust-proof layer is applied to the remaining magnet.

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