Preparation method of inductor and inductor

Abstract

The invention provides a preparation method of an inductor and the inductor, and the preparation method comprises the following steps: (1) mixing a magnetic powder raw material with a glue solution, sequentially carrying out granulation and pressing to obtain a magnetic core, and carrying out primary curing on the magnetic core; (2) winding a conductor coil, soaking the conductor coil into an insulating liquid for insulating treatment to form an insulating layer, and then filling the conductor coil into the magnetic core; and (3) magnetic slurry is injected into the magnetic core in the step (2), secondary curing is carried out, and an inductor blank is obtained. The coil can be prevented from being deformed, and the parasitic capacitance of the inductor is greatly reduced through insulation protection treatment.

Description

Technical Field

[0001] The present invention belongs to the field of inductors, and relates to a method for manufacturing an inductor and an inductor. Background Art

[0002] Currently, according to different manufacturing methods, inductors are generally divided into molded inductors, wound inductors, and multilayer inductors. Among them, the manufacturing process of a molded inductor requires first mixing a certain amount of iron powder, binder, release powder, etc. and granulating, then filling the granulated powder and the coil into a mold, pressing under certain pressure, temperature and other conditions, and then folding the corners. However, since the coil of the product requires a very high pressure for pressing, it has high requirements for the molding machine and the mold. Especially, the coil is very easy to deform under a very high pressure, the enameled layer is easily damaged, the distance between the coils changes greatly, resulting in an increase in the parasitic capacitance between the layers of the coil, and the defect rate between the layers of the coil is very high. The manufacturing process of a wound inductor is similar to that of a molded inductor. It is necessary to granulate first, make the granulated powder into a magnetic core, bake and cure the magnetic core, then wind the wire, place the semi-finished product after winding and a certain amount of powder in a mold for pressing and molding, and then process through a series of processes. The pressing process is likely to cause serious deformation of the coil, resulting in an increase in the parasitic capacitance of the coil. The manufacturing of a multilayer inductor requires first preparing a slurry, then coating and forming a blank, screen-printing Ag paste, and then processing through processes such as pressing, sintering, terminal Ag, electroplating, etc. Among them, the sintering process is high-temperature sintering, and the Ag layer will diffuse along the gaps between the powders, resulting in poor insulation between the coils of each layer and an increase in parasitic capacitance.

[0003] CN202183292U discloses an improved molded inductor, which is processed by general processes such as spot welding the coil and then molding. However, when using spot welding the coil and then molding, since the coil has no positioning, the coil is very easy to shift and deform during molding, and under the action of high pressure, the distance between the coils becomes smaller, resulting in an increase in the parasitic capacitance between the layers of the coil, and the defect rate between the layers of the coil is very high.

[0004] CN108648901A discloses a manufacturing process of an electronic component using the T-core process. First, the T-core is pressed, then the wire is wound on the T-core, and then processed through processes such as molding. However, the coil is wound on the T-core. During the secondary pressing, there is protection of the T-core inside and at the bottom of the coil, but the coil will still have a certain outward expansion deformation after being pressed, especially the deformation of the coil in the vertical direction will be relatively serious, and the enameled layer is severely damaged. The distance between the coils in the vertical direction becomes smaller, and the parasitic capacitance of the coil and the defect rate between the layers of the coil become higher, thus affecting the electrical characteristics of the product.

[0005] Therefore, solving the problems of coil damage during the manufacturing process of the inductor and reducing the overall capacitance of the coil is very important for improving the product performance. Summary of the Invention

[0006] Aiming at the deficiencies of the existing technology, the purpose of the present invention is to provide a method for manufacturing an inductor and an inductor, so that the coil does not need to bear pressure during the whole manufacturing process, avoiding the deformation of the coil, and through insulation protection treatment, greatly reducing the parasitic capacitance of the inductor.

[0007] To achieve this purpose, the present invention adopts the following technical solutions:

[0008] In the first aspect, the present invention provides a method for manufacturing an inductor, and the manufacturing method includes:

[0009] (Ⅰ) Mix the magnetic powder raw material with the glue solution, and successively perform granulation and pressing to obtain a magnetic core, and perform primary curing on the magnetic core;

[0010] (Ⅱ) Wind a conductor coil, and immerse the conductor coil in an insulating liquid for insulation treatment to form an insulating layer, and then fill the conductor coil into the magnetic core;

[0011] (Ⅲ) Inject magnetic slurry into the magnetic core in step (Ⅱ), and perform secondary curing to obtain an inductor blank.

[0012] In the manufacturing method provided by the present invention, the coil does not need to bear pressure during the whole process. Only need to inject the magnetic slurry into the magnetic core containing the coil, and through curing and forming, avoid the deformation of the coil, improve the quality and electrical performance of the inductor product; in addition, through special insulation protection treatment of the coil, the coil can be further protected, improve the insulation of the coil, greatly reduce the parasitic capacitance of the inductor, improve the applicability of the inductor, and make it suitable for different application scenarios.

[0013] It should be noted that the manufacturing processes of the existing molded inductors and wound inductors both include hot pressing or cold pressing forming processes, and both hot pressing and cold pressing require high pressure for pressing and forming. And the greater pressure will inevitably cause the deformation of the conductor coil. The outer enamel coating mold and the coil spacing of the deformed coil will change, thus affecting the insulation characteristics of the inductor, especially resulting in a significant increase in the parasitic capacitance of the inductor. In the manufacturing method of the present invention, there is no need to press the conductor coil, and at the same time, an insulating layer is coated on the surface of the conductor coil, which can effectively reduce the parasitic inductance.

[0014] As a preferred technical solution of the present invention, in step (Ⅰ), the magnetic powder raw material includes any one or at least two combinations of alloy powder, amorphous powder or nanocrystalline powder, including but not limited to the mixed powder of alloy powder and amorphous powder, the combination of amorphous powder and nanocrystalline powder, the combination of alloy powder and nanocrystalline powder, or the combination of alloy powder, amorphous powder and nanocrystalline powder.

[0015] The alloy powder includes, but is not limited to, ferroalloy powder, copper alloy powder, nickel alloy powder, cobalt alloy powder, aluminum alloy powder or titanium alloy powder. The amorphous powder includes, but is not limited to, iron-silicon-boron amorphous powder, iron-nickel-boron amorphous powder or iron-chromium-boron-silicon amorphous powder. The nanocrystalline powder includes, but is not limited to, iron-silicon-niobium nanocrystalline powder, iron-silicon-niobium-boron nanocrystalline powder or copper-zinc-tin-sulfur nanocrystalline powder.

[0016] Preferably, the adhesive solution includes any one or a combination of at least two of epoxy resin, silicone resin or amino resin, including but not limited to the combination of epoxy resin and silicone resin, the combination of silicone resin and amino resin, the combination of epoxy resin and amino resin, or the combination of epoxy resin, silicone resin and amino resin.

[0017] As a preferred technical solution of the present invention, in step (Ⅰ), the pressure of the pressing is 200-1000 MPa, for example, it can be 200 MPa, 240 MPa, 300 MPa, 400 MPa, 500 MPa, 600 MPa, 700 MPa, 800 MPa, 850 MPa, 900 MPa, 950 MPa or 1000 MPa, but is not limited to the listed values, and other unlisted values within this value range are equally applicable.

[0018] Preferably, the temperature of the first curing is 100-200 °C, for example, it can be 100 °C, 110 °C, 120 °C, 130 °C, 140 °C, 150 °C, 160 °C, 170 °C, 180 °C, 190 °C or 200 °C, but is not limited to the listed values, and other unlisted values within this value range are equally applicable.

[0019] Preferably, the time of the first curing is 5-60 min, for example, it can be 5 min, 10 min, 15 min, 20 min, 25 min, 30 min, 35 min, 40 min, 55 min, 50 min, 55 min or 60 min, but is not limited to the listed values, and other unlisted values within this value range are equally applicable.

[0020] It should be noted that in the present invention, the powder obtained by granulation is screened in a certain mesh range and then pressed into a magnetic core with an open box structure in a mold, and the first curing is achieved by baking the magnetic core. The present invention does not specifically limit the internal structure of the magnetic core, and those skilled in the art can adjust it according to the actual situation. For example, the inside of the magnetic core is a cavity, or a magnetic column can be pressed inside the magnetic core to position the conductor coil. After the conductor coil is filled into the magnetic core, the two ends of the conductor coil can be led out from the top lead of the magnetic core or from the side of the magnetic core.

[0021] As a preferred technical solution of the present invention, in step (Ⅱ), the insulating liquid includes a mixed solution of a hydrophilic organic resin and water.

[0022] Preferably, the mass ratio of the hydrophilic organic resin to water in the mixed solution is 1:(3-6). For example, it can be 1:3, 1:3.5, 1:4, 1:4.5, 1:5, 1:5.5 or 1:6, but is not limited to the listed values. Other unlisted values within this range are equally applicable.

[0023] Preferably, the hydrophilic organic resin includes any one or a combination of at least two of PEG (Polyethylene glycol), PVA (Polyvinyl Alcohol), PVP (Polyvinyl Pyrrolidone), hydroxyethyl cellulose, and polyethylene oxide.

[0024] In the present invention, the hydrophilic organic resin forms a colloidal mixture with certain adhesiveness after being dissolved in water.

[0025] Preferably, the time for the insulation treatment is 10-60 min. For example, it can be 10 min, 15 min, 20 min, 25 min, 30 min, 35 min, 40 min, 45 min, 50 min, 55 min or 60 min, but is not limited to the listed values. Other unlisted values within this range are equally applicable.

[0026] As a preferred technical solution of the present invention, in step (II), the preparation method further includes: after the insulation treatment is completed, baking the inductor coil.

[0027] Preferably, the temperature for the baking treatment is 60-90 °C. For example, it can be 60 °C, 65 °C, 70 °C, 75 °C, 80 °C, 85 °C or 90 °C, but is not limited to the listed values. Other unlisted values within this range are equally applicable.

[0028] Preferably, the time for the baking treatment is 30-120 min. For example, it can be 30 min, 35 min, 40 min, 50 min, 60 min, 70 min, 80 min, 90 min, 100 min, 110 min, 115 min or 120 min, but is not limited to the listed values. Other unlisted values within this range are equally applicable.

[0029] In the present invention, baking the conductor coil after insulation treatment for a certain time and temperature can improve the bonding strength between the insulating liquid and the paint film layer of the conductor coil to form a complete insulating layer. The thickness of the insulating layer can be adjusted by adjusting the concentration of the insulating liquid. When the concentration increases, the thickness of the insulating layer also increases.

[0030] As a preferred technical solution of the present invention, in step (III), the method for preparing the magnetic paste includes: mixing metal powder, organic solvent, silica powder, insulating glue and binder, and performing vacuum degassing treatment.

[0031] Preferably, the upper surface of the magnetic paste injected into the magnetic core is flush with the top end of the magnetic core.

[0032] The metal powder includes but is not limited to iron powder, copper powder, nickel powder, cobalt powder, aluminum powder or titanium powder, and iron powder is preferably used; the binder can be epoxy resin; the organic solvent can be acetone, ethyl acetate, n-propanol or ethanol.

[0033] Preferably, the preparation method further includes: stirring and heating and curing the magnetic paste injected into the magnetic core in sequence.

[0034] In the present invention, the magnetic paste is injected along the open end of the magnetic core so that the upper surface of the magnetic paste is flush with the top end of the magnetic core. Through stirring and preliminary heating and curing, the formed magnetic paste completely covers the conductor coil and is flush with the upper surface of the magnetic core.

[0035] Preferably, the temperature of the secondary curing is 150 - 200 °C, for example, it can be 150 °C, 155 °C, 160 °C, 165 °C, 170 °C, 175 °C, 180 °C, 185 °C, 190 °C, 195 °C or 200 °C, but is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0036] Preferably, the time of the secondary curing is 30 - 150 min, for example, it can be 30 min, 35 min, 40 min, 50 min, 60 min, 70 min, 80 min, 90 min, 100 min, 110 min, 115 min, 120 min, 130 min, 140 min, 145 min or 150 min, but is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0037] It should be noted that after heating and curing the magnetic paste in the magnetic core in the present invention, a combined body of a conductor coil, a magnetic core and a casting body is made, and then the above combined body is placed in a high-temperature oven for baking to achieve secondary curing.

[0038] As a preferred technical solution of the present invention, the preparation method further includes: successively performing lead bending and forming, roll spraying, paint stripping treatment and electroplating treatment on the inductor blank to obtain the inductor.

[0039] In a second aspect, the present invention provides an inductor, which is prepared by the preparation method described in the first aspect, and includes a magnetic core, the magnetic core is provided with a receiving groove, a conductor coil is arranged in the receiving groove, the outer surface of the conductor coil is covered with an insulating layer, the receiving groove is also filled with a casting body, and the casting body wraps the conductor coil.

[0040] The inductor provided by the present invention has lower parasitic capacitance, higher electrical performance and strong applicability.

[0041] As a preferred technical solution of the present invention, the wall thickness of the magnetic core is 0.05-0.5 mm, for example, it can be 0.05 mm, 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, 0.4 mm, 0.45 mm or 0.5 mm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0042] The upper surface of the casting body is flush with the top of the magnetic core to completely cover the conductor coil.

[0043] As a preferred technical solution of the present invention, the conductor coil includes a wire, and the outer surface of the wire is covered with a paint film layer.

[0044] Preferably, the ratio of the dielectric constants of the insulating layer and the paint film layer is 1:(8-12), for example, it can be 1:8, 1:8.2, 1:8.5, 1:9, 1:9.5, 1:10, 1:10.5, 1:11, 1:11.2, 1:11.5, 1:11.8 or 1:12, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable. Preferably, the dielectric constant of the insulating layer is 1 / 10 of the paint film layer, which can better reduce the parasitic capacitance of the conductor coil.

[0045] The present invention takes into account the dielectric properties of the conductor coil. At the same time, in order to reduce parasitic capacitance, according to the capacitance calculation formula C=εS / d, where C is capacitance, ε is relative dielectric constant, S is the facing area of ​​the capacitor plates, and d is the distance between the capacitor plates, the relationship between the dielectric constants of the insulating layer and the paint film layer defined in the present invention is obtained.

[0046] Preferably, the conductive wire comprises a copper wire.

[0047] Preferably, the cross section of the wire is circular or rectangular.

[0048] The numerical range described in the present invention not only includes the point values ​​listed above, but also includes any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0049] Compared with the prior art, the beneficial effects of the present invention are as follows: For a method for preparing an inductor and the inductor provided by the present invention, the coil does not need to bear pressure during the entire manufacturing process. Only by injecting magnetic paste into the magnetic core containing the coil and curing and molding, the deformation of the coil can be avoided, improving the quality and electrical performance of the inductor product. In addition, through special insulation protection treatment of the coil, the coil can be further protected, the insulation of the coil is improved, the parasitic capacitance of the inductor is greatly reduced, the applicability of the inductor is improved, and it is applicable to different application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 FIG. is a schematic structural diagram of an inductor provided by a specific embodiment of the present invention;

[0051] Figure 2 FIG. is a schematic structural diagram of a magnetic core provided by a specific embodiment of the present invention;

[0052] Figure 3 FIG. is a schematic structural diagram of a magnetic core provided by a specific embodiment of the present invention;

[0053] Figure 4 FIG. is a schematic structural diagram of a flat conductor coil provided by a specific embodiment of the present invention;

[0054] Figure 5 FIG. is a schematic cross-sectional view of a flat conductor coil provided by a specific embodiment of the present invention;

[0055] Figure 6 FIG. is a schematic structural diagram of a circular conductor coil provided by a specific embodiment of the present invention;

[0056] Figure 7 FIG. is a schematic cross-sectional view of a circular conductor coil provided by a specific embodiment of the present invention.

[0057] Wherein, 1 - inductor; 2 - magnetic core; 3 - conductor coil; 4 - magnetic column; 5 - insulating layer; 6 - wire; 7 - paint film layer. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0058] It should be understood that in the description of the present invention, the orientation or positional relationship indicated by the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention. In the description of the present invention, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0059] The technical solution of the present invention will be further described below in conjunction with the accompanying drawings and through specific embodiments.

[0060] In a specific embodiment, the present invention provides a method for preparing an inductor, which specifically includes the following steps:

[0061] (1) Mix the magnetic powder raw material with the glue solution, and successively perform granulation and pressing to obtain a magnetic core 2, and perform primary curing on the magnetic core 2, wherein the magnetic powder raw material includes any one or at least two combinations of alloy powder, amorphous powder or nanocrystalline powder; the glue solution includes any one or at least two combinations of epoxy resin, silicone resin or amino resin, the pressing pressure is 200-1000 MPa, the temperature of primary curing is 100-200 °C, and the time of primary curing is 5-60 min;

[0062] (2) Wind a conductor coil 3, and immerse the conductor coil 3 in an insulating liquid for 10-60 min of insulation treatment to form an insulating layer 5, and then perform a baking treatment at a temperature of 60-90 °C for 30-120 min, and then fill the conductor coil 3 into the magnetic core 2, wherein the insulating liquid uses a mixed solution of hydrophilic organic resin and water with a mass ratio of 1:(3-6);

[0063] (3) Mix metal powder, organic solvent, silicon dioxide powder, insulating glue and binder, and perform vacuum degassing treatment to obtain a magnetic slurry;

[0064] (4) Inject the magnetic slurry into the magnetic core 2 so that the upper surface of the magnetic slurry is flush with the top end of the magnetic core 2, successively perform stirring and heat curing, and then perform secondary curing at 150-200 °C for 30-150 min to obtain an inductor blank;

[0065] (5) Perform lead bending forming, roll spraying, paint stripping treatment and electroplating treatment on the inductor blank in sequence to obtain the inductor 1.

[0066] In another specific embodiment, the present invention provides an inductor 1, and the inductor 1 is prepared by using the preparation method provided in a specific embodiment, as Figure 1 shown, the inductor 1 includes the magnetic core 2, the magnetic core 2 is provided with a receiving groove, a conductor coil 3 is arranged in the receiving groove, an insulating layer 5 is coated on the outer surface of the conductor coil 3, and a casting body is further filled in the receiving groove, and the casting body wraps the conductor coil 3.

[0067] As Figure 2 And Figure 3As shown, the magnetic core 2 has an open box structure. The internal structure of the magnetic core 2 is not specifically limited, and those skilled in the art can adjust it according to actual situations. For example, the inside of the magnetic core 2 is a cavity, or magnetic columns 4 can be pressed inside the magnetic core 2 to position the conductor coil 3. After filling the conductor coil 3 into the magnetic core 2, the two ends of the conductor coil 3 can be led out from the top end of the magnetic core 2 or from the side of the magnetic core 2. The wall thickness of the magnetic core 2 is 0.05 - 0.5 mm. The conductor coil 3 includes a wire 6, and the wire 6 includes but is not limited to copper wire. As Figure 4 as Figure 5 shown, the cross-section of the wire 6 can be rectangular, wound into a flat coil; as Figure 6 as Figure 7 shown, it can also be a wire 6 with a circular cross-section, wound into a circular coil. The outer surface of the wire 6 is coated with a paint film layer 7, and the ratio of the dielectric constant of the insulating layer 5 to that of the paint film layer 7 is 1:(8 - 12).

[0068] Example 1

[0069] This example provides a method for preparing an inductor, which specifically includes the following steps:

[0070] (1) Mix amorphous powder and alloy powder according to a mass ratio of 4:6, and add epoxy resin glue solution for mixing and granulation (the mass ratio of the mixed epoxy resin glue solution is 2.4%), obtain granular powder materials, screen them and then load them into a mold, and press under a pressure of 0.5 MPa to obtain a magnetic core 2 with an open box structure and a wall thickness of 0.1 mm;

[0071] (2) Cure the magnetic core 2 at 180 °C for 45 min for the first time;

[0072] (3) Mix hydrophilic organic resin and water according to a mass ratio of 1:3 to obtain an insulating liquid;

[0073] (4) Wind the conductor coil 3, and soak the conductor coil 3 in the insulating liquid for 30 min for insulation treatment to form an insulating layer 5, then bake it at a temperature of 70 °C for 90 min, and then fill the conductor coil 3 into the magnetic core 2, wherein the dielectric constant of the formed insulating layer 5 is 1 / 10 of that of the paint film of the conductor coil 3;

[0074] (5) Mix iron powder, acetone, silicon dioxide powder, insulating glue and binder, and perform vacuum degassing treatment to obtain a magnetic slurry;

[0075] (6) Inject the magnetic paste into the magnetic core 2 so that the magnetic paste covers the conductor coil 3 and is flush with the top end of the magnetic core 2. Stir and heat-cure in sequence, and then perform secondary curing at 180 °C for 120 min to obtain an inductor blank;

[0076] (7) Perform lead bending and forming, roll spraying, laser paint stripping treatment, and electroplating treatment on the inductor blank in sequence to obtain the inductor 1.

[0077] Example 2

[0078] This example provides a method for preparing an inductor, which specifically includes the following steps:

[0079] (1) Mix the amorphous powder and the nanocrystalline powder according to a mass ratio of 4:6, and add silicone resin solution for mixing and granulation (the mass ratio of the mixed epoxy resin solution is 2.4%). Obtain granular powder materials, screen them and load them into a mold, and press under a pressure of 0.2 MPa to obtain a magnetic core 2 with an open-box structure and a wall thickness of 0.2 mm;

[0080] (2) Perform primary curing on the magnetic core 2 at 100 °C for 60 min;

[0081] (3) Mix the hydrophilic organic resin and water according to a mass ratio of 1:3 to obtain an insulating liquid;

[0082] (4) Wind the conductor coil 3, and soak the conductor coil 3 in the insulating liquid for 10 min for insulation treatment to form an insulating layer 5. Then perform baking treatment at a temperature of 60 °C for 80 min, and then fill the conductor coil 3 into the magnetic core 2. Among them, the dielectric constant of the formed insulating layer 5 is 1 / 8 of the paint film of the conductor coil 3;

[0083] (5) Mix iron powder, acetone, silicon dioxide powder, insulating glue, and binder, and perform vacuum degassing treatment to obtain magnetic paste;

[0084] (6) Inject the magnetic paste into the magnetic core 2 so that the magnetic paste covers the conductor coil 3 and is flush with the top end of the magnetic core 2. Stir and heat-cure in sequence, and then perform secondary curing at 150 °C for 150 min to obtain an inductor blank;

[0085] (7) Perform lead bending and forming, roll spraying, laser paint stripping treatment, and electroplating treatment on the inductor blank in sequence to obtain the inductor 1.

[0086] Example 3

[0087] This example provides a method for preparing an inductor, which specifically includes the following steps:

[0088] (1) Add epoxy resin glue solution to alloy powder and mix to granulate (the mass ratio of the mixed epoxy resin glue solution is 2.4%), obtain granular powder material, screen it and then load it into a mold, press it under a pressure of 1 MPa to obtain a magnetic core 2 with an open-box structure and a wall thickness of 0.5 mm;

[0089] (2) Cure the magnetic core 2 at 200 °C for 15 min for the first time;

[0090] (3) Mix hydrophilic organic resin and water in a mass ratio of 1:3 to obtain an insulating liquid;

[0091] (4) Wind a conductor coil 3, soak the conductor coil 3 in the insulating liquid for 60 min for insulation treatment to form an insulating layer 5, then bake it at 90 °C for 30 min, and then fill the conductor coil 3 into the magnetic core 2. Among them, the dielectric constant of the formed insulating layer 5 is 1 / 12 of the paint film of the conductor coil 3;

[0092] (5) Mix iron powder, acetone, silicon dioxide powder, insulating glue and binder, and perform vacuum degassing treatment to obtain magnetic slurry;

[0093] (6) Inject the magnetic slurry into the magnetic core 2 so that the magnetic slurry covers the conductor coil 3 and is flush with the top of the magnetic core 2, stir and heat-cure it in sequence, and then perform a second cure at 250 °C for 60 min to obtain an inductor blank;

[0094] (7) Perform lead bending and forming, roll spraying, laser paint stripping treatment and electroplating treatment on the inductor blank in sequence to obtain an inductor 1.

[0095] Example 4

[0096] This example provides a method for preparing an inductor. The difference from Example 1 is that the mass ratio of hydrophilic organic resin to water in the insulating liquid is 1:4, and the rest of the operating conditions and process parameters are the same as those in Example 1.

[0097] Example 5

[0098] This example provides a method for preparing an inductor. The difference from Example 1 is that the mass ratio of hydrophilic organic resin to water in the insulating liquid is 1:5, and the rest of the operating conditions and process parameters are the same as those in Example 1.

[0099] Example 6

[0100] This example provides a method for preparing an inductor. The difference from Example 1 is that the mass ratio of hydrophilic organic resin to water in the insulating liquid is 1:6, and the rest of the operating conditions and process parameters are the same as those in Example 1.

[0101] Example 7

[0102] This example provides a method for preparing an inductor. The difference from Example 1 is that the mass ratio of the hydrophilic organic resin to water in the insulating liquid is 1:2, and the remaining operating conditions and process parameters are the same as those in Example 1.

[0103] Example 8

[0104] This example provides a method for preparing an inductor. The difference from Example 1 is that the mass ratio of the hydrophilic organic resin to water in the insulating liquid is 1:7, and the remaining operating conditions and process parameters are the same as those in Example 1.

[0105] Comparative Example 1

[0106] This comparative example provides a method for preparing an inductor, which specifically includes the following steps:

[0107] (1) Mix amorphous powder and carbonyl iron powder according to a mass ratio of 4:6, and add epoxy resin adhesive solution for mixing and granulation (the mass ratio of the mixed epoxy resin adhesive solution is 2.4%), to obtain granular powder. After screening, it is loaded into a mold, and the coil and wire 6 terminals are placed by spot welding. Then a layer of powder is laid flat on it. Subsequently, under the condition of 170 °C, a pressure of 5.0 t / cm 2 is applied for hot pressing for 90 s to obtain an inductor 1 blank;

[0108] (2) Place the inductor 1 blank in an oven at 180 °C for baking and curing for 2 h;

[0109] (3) Spray an insulating liquid on the surface of the cured inductor 1 blank to form a 10-μm insulating layer 5, obtaining a semi-finished inductor 1;

[0110] (4) Perform terminal cutting and lead bending and forming on the semi-finished inductor 1 in sequence to obtain inductor 1.

[0111] Comparative Example 2

[0112] This comparative example provides a method for preparing an inductor, which specifically includes the following steps:

[0113] (1) Mix amorphous powder and carbonyl iron powder according to a mass ratio of 4:6, and add epoxy resin adhesive solution for mixing and granulation (the mass ratio of the mixed epoxy resin adhesive solution is 2.4%), to obtain granular powder. After screening, it is loaded into a mold, and the coil and wire 6 terminals are placed by spot welding. Then a layer of powder is laid flat on it. Subsequently, under the condition of 170 °C, a pressure of 5.0 t / cm 2 is applied for hot pressing for 90 s to obtain an inductor 1 blank;

[0114] (2) Place the inductor 1 blank in an oven at 180 °C for baking and curing for 2 h;

[0115] (3) Spray an insulating liquid on the surface of the solidified inductor 1 blank to form an insulating layer 5 with a thickness of 10 μm, obtaining a semi-finished inductor 1;

[0116] (4) Use a laser paint stripper to strip the paint of the semi-finished inductor 1 to form an electrode area;

[0117] (5) After the paint stripping is completed, electroplate a Cu layer, a Ni layer, and a Sn layer on the surface of the semi-finished inductor 1 in sequence to complete the production of the electrode layer, obtaining the inductor 1.

[0118] The present invention uses an ADEXAX-1152D DC impedance meter to measure the impedance values of the inductors 1 prepared in Examples 1 to 8 and Comparative Examples 1 to 2, and the results are shown in Table 1.

[0119] The present invention uses an Agilent 4284A tester to measure the parasitic capacitances of the inductors 1 prepared in Examples 1 to 8 and Comparative Examples 1 to 2, and the results are shown in Table 1.

[0120] Table 1

[0121] Serial number DC impedance (mΩ) Parasitic capacitance (nF) Example 1 28.71 10.2 Example 2 29.40 11.5 Example 3 28.73 10.3 Example 4 28.64 10.6 Example 5 28.68 10.7 Example 6 28.69 11.0 Example 7 28.92 10.6 Example 8 28.68 12.7 Comparative example 1 43.51 29.8 Comparative example 2 34.62 24.6

[0122] As can be seen from Table 1, the DC impedances and parasitic capacitances of the inductors 1 prepared in Examples 1 to 8 are much lower than those in Comparative Examples 1 to 2. This is mainly because in the preparation process of Comparative Examples 1 to 2, the coil is hot-pressed under high pressure, which damages the paint film layer 7 on the surface of the coil, and under the action of high pressure, the distance between the layers of the coil is shortened, resulting in an increase in parasitic capacitance.

[0123] Compared with Example 1, the parasitic capacitances of Examples 7 and 8 have increased. This is mainly because the content of the hydrophilic organic resin in the insulating liquid prepared in Example 7 is too high, resulting in too large a thickness of the insulating layer 5, reducing the electrical performance of the conductor coil 3. The content of the hydrophilic organic resin in the insulating liquid prepared in Example 8 is too low, and during the soaking process, the insulating liquid cannot effectively coat the conductor coil 3, resulting in a decrease in the bonding strength with the paint film and an increase in parasitic capacitance.

[0124] The preparation method provided by the present invention avoids high-pressure pressing of the coil and forms an insulating layer 5 on the surface of the conductor coil 3 for protection, greatly improving the insulation of the conductor coil 3 and at the same time reducing the parasitic capacitance of the inductor 1.

[0125] The applicant declares that the above description is only the specific implementation manner 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 thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the protection scope and the disclosure scope of the present invention.

Claims

1. A method for preparing an inductor, characterized in that, the preparation method includes: (Ⅰ) Mixing magnetic powder raw materials with a glue solution, and successively performing granulation and pressing to obtain a magnetic core, and performing primary curing on the magnetic core; (Ⅱ) Winding a conductor coil, and immersing the conductor coil in an insulating liquid for insulation treatment to form an insulating layer, and then filling the conductor coil into the magnetic core; (Ⅲ) Injecting a magnetic slurry into the magnetic core in step (Ⅱ), and performing secondary curing to obtain an inductor embryo.

2. The preparation method according to claim 1, characterized in that, in step (Ⅰ), the magnetic powder raw material includes any one or a combination of at least two of alloy powder, amorphous powder or nanocrystalline powder; Preferably, the glue solution includes any one or a combination of at least two of epoxy resin, silicone resin or amino resin.

3. The preparation method according to claim 1 or 2, characterized in that, in step (Ⅰ), the pressure of the pressing is 200 - 1000 MPa; Preferably, the temperature of the primary curing is 100 - 200 °C; Preferably, the time of the primary curing is 5 - 60 min.

4. The preparation method according to any one of claims 1 - 3, characterized in that, in step (Ⅱ), the insulating liquid includes a mixed solution of a hydrophilic organic resin and water; Preferably, the mass ratio of the hydrophilic organic resin to water in the mixed solution is 1:(3 - 6); Preferably, the hydrophilic organic resin includes any one or a combination of at least two of PEG, PVA, PVP, carboxymethyl cellulose, polyethylene oxide; Preferably, the time of the insulation treatment is 10 - 60 min.

5. The preparation method according to any one of claims 1 - 4, characterized in that, in step (Ⅱ), the preparation method further includes: after the insulation treatment is completed, baking the inductor coil; Preferably, the temperature of the baking treatment is 60 - 90 °C; Preferably, the time of the baking treatment is 30 - 120 min.

6. The preparation method according to any one of claims 1 - 5, characterized in that, in step (Ⅲ), the preparation method of the magnetic slurry includes: Mixing metal powder, organic solvent, silicon dioxide powder, insulating glue and binder, and performing vacuum degassing treatment; Preferably, the upper surface of the magnetic slurry injected into the magnetic core is flush with the top end of the magnetic core; Preferably, the preparation method further includes: sequentially stirring and heat-curing the magnetic slurry injected into the magnetic core; Preferably, the temperature of the secondary curing is 150 - 200 °C; Preferably, the time of the secondary curing is 30 - 150 min.

7. The preparation method according to any one of claims 1 - 6, characterized in that, the preparation method further includes: successively performing lead bending and forming, rolling spraying, paint stripping treatment and electroplating treatment on the inductor embryo to obtain the inductor.

8. An inductor, characterized in that, The inductor described above is prepared by the preparation method described in any one of claims 1-7. The inductor includes a magnetic core, the magnetic core is provided with a receiving groove, a conductor coil is arranged in the receiving groove, an insulating layer is coated on the outer surface of the conductor coil, a casting body is further filled in the receiving groove, and the casting body wraps the conductor coil.

9. The inductor according to claim 8, wherein, the wall thickness of the magnetic core is 0.05-0.5 mm.

10. The inductor according to claim 8 or 9, wherein, the conductor coil includes a wire, and a paint film layer is coated on the outer surface of the wire; preferably, the ratio of the dielectric constant of the insulating layer to that of the paint film layer is 1:(8-12); preferably, the wire includes a copper wire; preferably, the cross section of the wire is circular or rectangular.

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