Coupling inductor

Abstract

The invention discloses a coupling inductor, and relates to the technical field of electronic components. The coupling inductor comprises a magnetic core, a mounting base, a first coil, a second coil, a terminal, an insulating part and a magnetic cover, the magnetic core and the terminal are both mounted on the mounting base, the first coil and the second coil are both wound on the magnetic core, are sequentially arranged in the axial direction of the magnetic core and are connected with the terminal, and the insulating part is arranged on the magnetic cover. The insulating part is arranged on the magnetic core in a sleeving manner and is positioned between the first coil and the second coil; the magnetic cover covers the mounting seat, the magnetic cover and the mounting seat define an internal space, the magnetic core is accommodated in the internal space, an air gap is reserved between the magnetic core and the bottom of the magnetic cover, and the air gap is filled with a magnetic layer. The technical problem that in an existing coupling inductor, due to the fact that an air gap exists, edge magnetic flux radiates a coil, and temperature rise of the inductor is caused is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic components, and in particular to a coupled inductor. Background Art

[0002] At present, high efficiency, energy saving and environmental protection have become the development direction of the electronics industry, and small size, low radiation and high power density design have become the mainstream design in the market. Since the technology of semiconductors such as gallium nitride and silicon carbide can greatly increase the switching frequency of the power supply and reduce losses, the product size can be further compressed. In the existing coupled inductors, there is an air gap between the magnetic core and the bottom of the magnetic cover, and there is a phenomenon of edge magnetic flux radiation to the coil, which leads to the temperature rise of the inductor. Summary of the invention

[0003] In view of this, the present invention provides a coupled inductor for solving the technical problem of the inductor temperature rise caused by the radiation of the edge magnetic flux to the coil due to the existence of an air gap in the existing coupled inductor.

[0004] In order to solve the above technical problems, the present invention adopts the following technical solution:

[0005] A coupled inductor, comprising a magnetic core, a mounting seat, a first coil, a second coil, a terminal, an insulating member and a magnetic cover, wherein the magnetic core and the terminal are both mounted on the mounting seat, the first coil and the second coil are both wound around the magnetic core and arranged in sequence along the axial direction of the magnetic core, and are respectively connected to the terminals, the insulating member is sleeved on the magnetic core and located between the first coil and the second coil; the magnetic cover is disposed on the mounting seat and enclosed with the mounting seat to form an internal space, the magnetic core is accommodated in the internal space, an air gap is left between the magnetic core and the bottom of the magnetic cover, and the air gap is filled with a magnetic layer.

[0006] In some embodiments of the coupled inductor, the steps of preparing the magnetic layer are as follows:

[0007] Provide epoxy resin raw materials;

[0008] Provide soft magnetic powder;

[0009] Performing insulation treatment on the soft magnetic powder;

[0010] The epoxy resin raw material and the soft magnetic powder are stirred and mixed in a weight ratio of 9:1 to obtain the magnetic layer in a fluid state.

[0011] In some embodiments of the coupled inductor, the viscosity (25° C.) of the epoxy resin raw material is 5000 cps-7000 cps.

[0012] In some embodiments of the coupled inductor, the step of providing soft magnetic powder includes:

[0013] Providing raw magnetic powder, wherein the raw magnetic powder is one of ferrite, iron silicon, iron silicon aluminum, and iron silicon chromium;

[0014] Providing 200 mesh, 300 mesh, and 400 mesh sieves, and sieving the raw magnetic powder;

[0015] The soft magnetic powder is obtained by mixing according to the proportion of +200 mesh at 5%-15%, -200 mesh and +300 mesh at 45%-55%, -300 mesh and +400 mesh at 20%-30%, and -400 mesh at 10%-20%.

[0016] In some embodiments of the coupled inductor, in the step of stirring and mixing the epoxy resin raw material and the soft magnetic powder in a weight ratio of 9:1, the stirring and mixing time is 15 min-20 min.

[0017] In some embodiments of the coupled inductor, the magnetic core includes a table and a column, the column is connected to the middle of the table, the diameter of the table is larger than the diameter of the column, so that the table has a boss protruding from the column, and the orthographic projection of the magnetic layer toward the boss toward the surface of the magnetic layer is at least partially located on the surface; the insulating member is a structural member made of a magnetic material.

[0018] In some embodiments of the coupled inductor, the first coil and the second coil are both flat, and the outer diameter of the first coil and the outer diameter of the second coil are equal to the diameter of the stage.

[0019] In some embodiments of the coupled inductor, an outer diameter of the insulating member is equal to an outer diameter of the first coil.

[0020] In some embodiments of the coupled inductor, the second coil is located on a side of the first coil facing away from the mounting base, and a distance between the side of the second coil facing away from the first coil and the bottom of the magnetic cover is greater than or equal to three times a distance between the side of the magnetic core facing away from the mounting base and the bottom of the magnetic cover.

[0021] In some embodiments of the coupled inductor, a groove is formed on the mounting base, and the platform is received in the groove.

[0022] Implementing the embodiments of the present invention will have at least the following beneficial effects:

[0023] The above-mentioned coupled inductor has the technical effect of reducing the radiation of the edge magnetic flux to the coil and further reducing the temperature rise of the inductor. Specifically, the present invention solves the technical problem of the inductor temperature rise caused by the radiation of the edge magnetic flux to the coil due to the existence of an air gap in the existing coupled inductor, and also has the following effects: First, the magnetic circuit can be closed to reduce the radiation of the edge magnetic flux to the coil, reduce the eddy current loss of the coil at the air gap, and improve the inductor efficiency; Second, after the magnetic circuit is closed, the inductance value is increased, and the impedance of the inductor is increased at the same time. For the same direction characteristics of the common-mode interference signal, the impedances of the two coils will be superimposed, suppressing the common-mode interference, and the EMC filtering effect is improved; for the characteristics of the opposite directions of the differential-mode current, the magnetic field between the two coils can form another loop along the middle insulating member to suppress the differential-mode signal interference. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 is a schematic structural diagram of a coupled inductor in one embodiment;

[0026] Figure 2 for Figure 1 An exploded schematic diagram of the structure of the coupled inductor shown;

[0027] Figure 3 for Figure 1 A partial structural schematic diagram of a coupled inductor is shown;

[0028] Figure 4 for Figure 3 A schematic diagram of a portion of the structure shown;

[0029] Figure 5 A schematic diagram of the structure of a mounting base in one embodiment;

[0030] Figure 6 is a schematic structural diagram of an insulating member in one embodiment;

[0031] Figure 7 A schematic diagram of a magnetic circuit in one embodiment of the present invention;

[0032] Figure 8 This is a comparison test diagram of the DC bias capabilities of the magnetic core and magnetic layer of various materials of the present invention;

[0033] Fig. 9 It is a side view comparing the losses of the magnetic core and magnetic layer of each material of the present invention.

[0034] in:

[0035] 1. Mounting seat; 11. Groove; 2. Magnetic core; 21. Platform; 22. Column; 3. First coil; 4. Second coil; 5. Insulator; 6. Magnetic cover; 7. Terminal; 8. Magnetic layer. DETAILED DESCRIPTION

[0036] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. Preferred embodiments of the present invention are provided in the drawings. However, the present invention can be implemented in many other different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0037] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0039] like Figure 1-7 As shown, in an embodiment of a coupled inductor, the coupled inductor comprises a magnetic core 2, a mounting base 1, a first coil 3, a second coil 4, a terminal 7, an insulating member 5 and a magnetic cover 6. The magnetic core 2 and the terminal 7 are both mounted on the mounting base 1. The first coil 3 and the second coil 4 are both wound around the magnetic core 2 and arranged in sequence along the axial direction of the magnetic core 2, and are respectively connected to the terminal 7. The insulating member 5 is sleeved on the magnetic core 2 and is located between the first coil 3 and the second coil 4. The magnetic cover 6 is covered on the mounting base 1 and enclosed with the mounting base 1 to form an internal space. The magnetic core 2 is accommodated in the internal space. An air gap is left between the magnetic core 2 and the bottom of the magnetic cover 6, and the air gap is filled with a magnetic layer 8.

[0040] In this embodiment, by filling the magnetic layer 8 in the air gap between the magnetic core 2 and the bottom of the magnetic cover 6, the technical problem of the inductor temperature rise caused by the radiation of the edge magnetic flux to the coil in the air gap in the existing coupled inductor is solved, and the following effects are also achieved: First, the magnetic circuit can be closed, the radiation of the edge magnetic flux to the coil can be reduced, the eddy current loss of the coil in the air gap can be reduced, and the inductor efficiency can be improved; Second, after the magnetic circuit is closed, the inductance value is increased, and the impedance of the inductor is increased at the same time. For the same direction characteristics of the common-mode interference signal, the impedances of the two coils will be superimposed, the common-mode interference is suppressed, and the EMC filtering effect is improved; for the characteristics of the opposite directions of the differential-mode current, the magnetic field between the two coils can form another loop along the middle insulating member 5 to suppress the differential-mode signal interference.

[0041] In one embodiment of the coupled inductor, the steps for preparing the magnetic layer 8 are as follows:

[0042] Provide epoxy resin raw materials.

[0043] Provides soft magnetic powder.

[0044] Insulation treatment of soft magnetic powder.

[0045] The epoxy resin raw material and the soft magnetic powder are stirred and mixed in a weight ratio of 9:1 to obtain a magnetic layer 8 in a fluid state.

[0046] In this embodiment, the magnetic layer 8 of the present invention is made of epoxy resin and soft magnetic powder. By setting the weight ratio to 9:1, a magnetic layer 8 in a fluid state can be obtained. After filling the air gap, the filling can be solidified, so that it can be more fully filled into the air gap and contact the bottom of the magnetic core 2 and the magnetic cover 6 respectively, so as to better reduce the radiation of the edge magnetic flux to the coil.

[0047] In one embodiment of the coupled inductor, the viscosity (25° C.) of the epoxy resin raw material is 5000 cps-7000 cps.

[0048] In this embodiment, by selecting epoxy resin raw materials with lower viscosity and then combining them with soft magnetic powder by weight ratio, a better mixing effect can be achieved, which is conducive to the full and uniform integration of the soft magnetic powder into the epoxy resin, thereby achieving a better magnetic effect.

[0049] In one embodiment of the coupled inductor, the step of providing soft magnetic powder includes:

[0050] Provide raw magnetic powder, which is one of ferrite, iron silicon, iron silicon aluminum, and iron silicon chromium.

[0051] Provide 200 mesh, 300 mesh, 400 mesh sieves, and screen the raw magnetic powder.

[0052] The soft magnetic powder is obtained by mixing according to the proportion of +200 mesh at 5%-15%, -200 mesh and +300 mesh at 45%-55%, -300 mesh and +400 mesh at 20%-30%, and -400 mesh at 10%-20%.

[0053] In this embodiment, by screening the particle size of the original magnetic powder, a magnetic material with high density, high effective magnetic permeability, high quality factor and low eddy current loss can be produced in the finished magnetic layer 8 .

[0054] In an embodiment of the coupled inductor, in the step of stirring and mixing the epoxy resin raw material and the soft magnetic powder in a weight ratio of 9:1, the stirring and mixing time is 15 minutes to 20 minutes.

[0055] In this embodiment, during the mixing process, high-speed discrete mixing is adopted, and the mixing time is 15 min-20 min, which is conducive to sufficient mixing.

[0056] In combination with the previous embodiment, in an embodiment of a coupled inductor, the steps of preparing the magnetic layer 8 are as follows:

[0057] Provide epoxy resin raw materials with a viscosity (25°C) of 5000cps-7000cps.

[0058] Providing raw magnetic powder, providing 200 mesh, 300 mesh and 400 mesh sieves, and sieving the raw magnetic powder, and mixing them according to the proportion of +200 mesh accounting for 5%-15%, -200 mesh and +300 mesh accounting for 45%-55%, -300 mesh and +400 mesh accounting for 20%-30%, and -400 mesh accounting for 10%-20%, to obtain soft magnetic powder.

[0059] Insulation treatment of soft magnetic powder.

[0060] The epoxy resin raw material and the soft magnetic powder are stirred and mixed in a weight ratio of 9:1, and a high-speed discrete method is used. The stirring and mixing time is 15 minutes to 20 minutes to obtain a magnetic layer 8 in a fluid state.

[0061] Example 1 of the steps for preparing the magnetic layer 8:

[0062] An epoxy resin raw material having a viscosity (25° C.) of 5000 cps was provided.

[0063] Providing raw magnetic powder, providing 200 mesh, 300 mesh and 400 mesh sieves, and sieving the raw magnetic powder, and mixing them according to the proportion of +200 mesh accounting for 5%, -200 mesh and +300 mesh accounting for 55%, -300 mesh and +400 mesh accounting for 20%, and -400 mesh accounting for 20%, to obtain soft magnetic powder.

[0064] Insulation treatment of soft magnetic powder.

[0065] The epoxy resin raw material and the soft magnetic powder were stirred and mixed in a weight ratio of 9:1, and a high-speed discrete method was used. The stirring and mixing time was 15 minutes to obtain a magnetic layer 8 in a fluid state.

[0066] Example 2 of the steps for preparing the magnetic layer 8:

[0067] An epoxy resin raw material having a viscosity (25°C) of 6000cps was provided.

[0068] Providing raw magnetic powder, providing 200 mesh, 300 mesh and 400 mesh sieves, and sieving the raw magnetic powder, and mixing them according to the proportion of +200 mesh accounting for 10%, -200 mesh and +300 mesh accounting for 50%, -300 mesh and +400 mesh accounting for 25%, and -400 mesh accounting for 15%, to obtain soft magnetic powder.

[0069] Insulation treatment of soft magnetic powder.

[0070] The epoxy resin raw material and the soft magnetic powder were stirred and mixed in a weight ratio of 9:1, and a high-speed discrete method was used. The stirring and mixing time was 15 minutes to obtain a magnetic layer 8 in a fluid state.

[0071] Example 3 of the steps for preparing the magnetic layer 8:

[0072] An epoxy resin raw material having a viscosity (25°C) of 6000cps was provided.

[0073] Providing raw magnetic powder, providing 200 mesh, 300 mesh and 400 mesh sieves, and sieving the raw magnetic powder, and mixing them according to the proportion of +200 mesh accounting for 10%, -200 mesh and +300 mesh accounting for 45%, -300 mesh and +400 mesh accounting for 30%, and -400 mesh accounting for 15%, to obtain soft magnetic powder.

[0074] Insulation treatment of soft magnetic powder.

[0075] The epoxy resin raw material and the soft magnetic powder were stirred and mixed in a weight ratio of 9:1, and a high-speed discrete method was used. The stirring and mixing time was 18 minutes to obtain a magnetic layer 8 in a fluid state.

[0076] Example 4 of the steps for preparing the magnetic layer 8:

[0077] An epoxy resin raw material having a viscosity (25°C) of 7000 cps was provided.

[0078] Providing raw magnetic powder, providing 200 mesh, 300 mesh and 400 mesh sieves, and sieving the raw magnetic powder, and mixing them according to the proportion of +200 mesh accounting for 15%, -200 mesh and +300 mesh accounting for 55%, -300 mesh and +400 mesh accounting for 20%, and -400 mesh accounting for 10%, to obtain soft magnetic powder.

[0079] Insulation treatment of soft magnetic powder.

[0080] The epoxy resin raw material and the soft magnetic powder were stirred and mixed in a weight ratio of 9:1, and a high-speed discrete method was used. The stirring and mixing time was 20 minutes to obtain a magnetic layer 8 in a fluid state.

[0081] Example 5 of the steps for preparing the magnetic layer 8:

[0082] An epoxy resin raw material having a viscosity (25°C) of 6000cps was provided.

[0083] Providing raw magnetic powder, providing 200 mesh, 300 mesh and 400 mesh sieves, and sieving the raw magnetic powder, and mixing them according to the proportion of +200 mesh accounting for 5%, -200 mesh and +300 mesh accounting for 55%, -300 mesh and +400 mesh accounting for 20%, and -400 mesh accounting for 20%, to obtain soft magnetic powder.

[0084] Insulation treatment of soft magnetic powder.

[0085] The epoxy resin raw material and the soft magnetic powder were stirred and mixed in a weight ratio of 9:1, and a high-speed discrete method was used. The stirring and mixing time was 20 minutes to obtain a magnetic layer 8 in a fluid state.

[0086] Example 5 of the steps for preparing the magnetic layer 8:

[0087] An epoxy resin raw material having a viscosity (25°C) of 6000cps was provided.

[0088] Providing raw magnetic powder, providing 200 mesh, 300 mesh and 400 mesh sieves, and sieving the raw magnetic powder, and mixing them according to the proportion of +200 mesh accounting for 10%, -200 mesh and +300 mesh accounting for 50%, -300 mesh and +400 mesh accounting for 30%, and -400 mesh accounting for 10%, to obtain soft magnetic powder.

[0089] Insulation treatment of soft magnetic powder.

[0090] The epoxy resin raw material and the soft magnetic powder were stirred and mixed in a weight ratio of 9:1, and a high-speed discrete method was used. The stirring and mixing time was 16 minutes to obtain a magnetic layer 8 in a fluid state.

[0091] In an embodiment of the coupled inductor, the magnetic core 2 includes a platform 21 and a column 22, the column 22 is connected to the middle of the platform 21, the diameter of the platform 21 is larger than the diameter of the column 22, so that the platform 21 has a boss protruding from the column 22, and the positive projection of the magnetic layer 8 toward the boss toward the surface of the magnetic layer 8 is at least partially located on the surface. The insulating member 5 is a structural member made of a magnetic material.

[0092] In this embodiment, the cross-sections of the table 21 and the column 22 are both circular. By setting the diameter of the table 21 to be larger than that of the column 22 and setting the column 22 in the middle of the table 21, the cross-section of the magnetic core 2 along the axial direction can be T-shaped, which is conducive to increasing the inductance value. In addition, it can be understood that the second coil 4 is closer to the air gap than the first coil 3, and there will be a small amount of magnetic leakage, so the inductance value is relatively small. The table 21 and the insulating member 5 and the insulating member 5 and the magnetic layer 8 form a magnetic circuit. In this way, when used as a common-mode inductor, it can form a magnetic circuit with the first coil 3 and the second coil 4 respectively, forming a separate small inductor, and the influence of magnetic leakage makes the two inductors offset. After that, there is still a small inductance value remaining, and this small inductance value can play a role in suppressing differential-mode signal interference.

[0093] The following effects are achieved by providing the insulating member 5 with magnetic properties: 1. forming respective loops between the two coils, which can be used as two power inductors; 2. between the first coil 3 and the second coil 4; 3. concentrating the magnetic field, improving the inductance value, and increasing the coupling coefficient.

[0094] Specifically, the insulating member 5 can be Ni-Zn ferrite, or Mn-Zn ferrite, or metal alloy powder, magnetic powder core, such as Sendust, Iron Silicon, Iron Nickel or other materials.

[0095] In an embodiment of the coupled inductor, the first coil 3 and the second coil 4 are both flat, and the outer diameter of the first coil 3 and the outer diameter of the second coil 4 are equal to the diameter of the platform 21 .

[0096] In this embodiment, the existing I-shaped magnetic core 2 wound by round enameled wire is replaced by a flat first coil 3 and a second coil 4 to enclose the magnetic core 2, so that the flat first coil 3 and the second coil 4 increase the cross-sectional area of ​​the wire with the same number of turns compared with the round enameled wire, reduce the DCR value of the first coil 3 and the second coil 4, achieve a greater overcurrent capacity, and thus improve the output efficiency.

[0097] In an embodiment of the coupled inductor, the outer diameter of the insulating member 5 is equal to the outer diameter of the first coil 3 .

[0098] In this embodiment, the size of the insulating member 5 matches that of the first coil 3 and the second coil 4 , and can achieve a better effect of isolating the first coil 3 from the second coil 4 .

[0099] In one embodiment of the coupled inductor, the second coil 4 is located on the side of the first coil 3 away from the mounting base 1, and the distance between the side of the second coil 4 away from the first coil 3 and the bottom of the magnetic cover 6 is greater than or equal to three times the distance between the side of the magnetic core 2 away from the mounting base 1 and the bottom of the magnetic cover 6.

[0100] In this embodiment, by such an arrangement, it is possible to avoid additional eddy current loss caused by the air gap on the coil radiation, thereby reducing the inductive heating.

[0101] In an embodiment of the coupled inductor, a groove 11 is formed on the mounting base 1 , and the platform 21 is received in the groove 11 .

[0102] The groove 11 can provide a positioning effect, so that the platform 21 can be accommodated in the groove 11, which makes it convenient to install the magnetic core 2.

[0103] In addition, the terminal 7 is arranged on the mounting base 1, and the first coil 3 and the second coil 4 are connected to the terminal 7 on the mounting base 1 by means of lead pins. By adopting the matching method of the magnetic cover 6 and the mounting base 1, the structural layout is compact, and it can also play a shielding effect. There is no need for additional sealing treatment on the top of the inductor, the production line is relatively shortened, and the production efficiency is improved. The shielding structure design reduces magnetic field leakage and has strong anti-electromagnetic interference performance. In addition, the flat single-layer double-coil insulation combination can improve the pressure resistance.

[0104] In addition, the magnetic core 2 and the magnetic layer 8 of the present invention can also be made of different materials. The material of the magnetic core 2 and the magnetic layer 8 is the same, and different materials also have different effects.

[0105] The magnetic core 2 and the magnetic layer 8 are made of iron silicon material, which can store more energy and achieve higher DC bias capability, and are suitable for the design of high-power energy storage application solutions, solving the problem of low saturation current of current ferrite high-current coupled inductors.

[0106] The core 2 and the magnetic layer 8 are made of iron-nickel materials with the strongest DC bias capability. At the same time, the inductor has lower losses, which is suitable for high-current, high-voltage, and high-power designs with high ripple voltages. This solves the temperature rise problem caused by inductor heating in current high-frequency and high-voltage applications.

[0107] The magnetic core 2 and the magnetic layer 8 are made of sendust material, which has lower core loss and lower magnetostriction coefficient, and reduces the probability of noise generation, thus solving the problem of high-frequency noise on the PCB board.

[0108] The magnetic core 2 and the magnetic layer 8 are made of iron-silicon-chromium material with moderate loss and DC bias, which is suitable for the design of small and medium power application solutions.

[0109] The magnetic core 2 and magnetic layer 8 are made of ferrite material, which has a more stable current linearity and is suitable for various low-pass filter circuit design requirements. In addition, the ui value of the ferrite core is higher than that of the magnetic powder core material, which can achieve a larger inductance value design. Example: loss conditions of various materials (ferrite for magnetic cover, characteristics of various material combinations).

[0110] Taking the magnetic cover 6 as ferrite, the DC bias capability comparison test reference of the magnetic core 2 and magnetic layer 8 of various material types Figure 8 , taking the magnetic cover 6 as ferrite, the loss comparison test of the magnetic core 2 of each material type is performed.

[0111] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0112] The above embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent application. It should be pointed out that, for those of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A coupled inductor, characterized in that: The coupled inductor includes a magnetic core, a mounting seat, a first coil, a second coil, a terminal, an insulating member and a magnetic cover. The magnetic core and the terminal are both mounted on the mounting seat. The first coil and the second coil are both wound around the magnetic core and arranged in sequence along the axial direction of the magnetic core and are respectively connected to the terminals. The insulating member is sleeved on the magnetic core and located between the first coil and the second coil. The magnetic cover is disposed on the mounting seat and enclosed with the mounting seat to form an internal space. The magnetic core is accommodated in the internal space. An air gap is left between the magnetic core and the bottom of the magnetic cover, and the air gap is filled with a magnetic layer.

2. The coupled inductor according to claim 1, wherein: The steps of preparing the magnetic layer are as follows: Provide epoxy resin raw materials; Provide soft magnetic powder; Performing insulation treatment on the soft magnetic powder; The epoxy resin raw material and the soft magnetic powder are stirred and mixed in a weight ratio of 9:1 to obtain the magnetic layer in a fluid state.

3. The coupled inductor according to claim 2, wherein: The viscosity (25° C.) of the epoxy resin raw material is 5000 cps-7000 cps.

4. The coupled inductor according to claim 2, wherein: The step of providing soft magnetic powder comprises: Providing raw magnetic powder, wherein the raw magnetic powder is one of ferrite, iron silicon, iron silicon aluminum, and iron silicon chromium; Providing 200 mesh, 300 mesh, and 400 mesh sieves, and sieving the raw magnetic powder; The soft magnetic powder is obtained by mixing according to the proportion of +200 mesh at 5%-15%, -200 mesh and +300 mesh at 45%-55%, -300 mesh and +400 mesh at 20%-30%, and -400 mesh at 10%-20%.

5. The coupled inductor according to claim 2, wherein: In the step of stirring and mixing the epoxy resin raw material and the soft magnetic powder in a weight ratio of 9:1, the stirring and mixing time is 15 minutes to 20 minutes.

6. The coupled inductor according to claim 1, wherein: The magnetic core includes a table and a column, the column is connected to the middle of the table, the diameter of the table is larger than the diameter of the column, so that the table has a boss protruding from the column, and the positive projection of the magnetic layer toward the boss toward the surface of the magnetic layer is at least partially located on the surface; the insulating part is a structural part made of magnetic material.

7. The coupled inductor according to claim 1, wherein: The first coil and the second coil are both flat, and the outer diameter of the first coil and the outer diameter of the second coil are equal to the diameter of the stage.

8. The coupled inductor according to claim 7, wherein: The outer diameter of the insulating member is equal to the outer diameter of the first coil.

9. The coupled inductor according to claim 1, wherein: The second coil is located on the side of the first coil away from the mounting seat, and the distance between the side of the second coil away from the first coil and the bottom of the magnetic cover is greater than or equal to three times the distance between the side of the magnetic core away from the mounting seat and the bottom of the magnetic cover.

10. The coupled inductor according to claim 6, wherein: The mounting seat is provided with a groove, and the platform body is accommodated in the groove.

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