Integrally-formed inductor

Abstract

The utility model provides an integrally-formed inductor which comprises a magnetic center pillar and a coil, the coil is wound on the outer side of the magnetic center pillar, the magnetic center pillar comprises at least one first magnetic core and at least one second magnetic core, the first magnetic cores and the second magnetic cores are alternately stacked, the relative permeability of the first magnetic cores is smaller than that of the second magnetic cores, and the first magnetic cores and the second magnetic cores are arranged in a staggered mode. The product of the saturation magnetic flux density of the first magnetic core and the cross sectional area of the first magnetic core is S1, the product of the saturation magnetic flux density of the second magnetic core and the cross sectional area of the second magnetic core is S2, and S1 is larger than or equal to 1.5 S2, so that the inductance performance is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of inductors, and particularly relates to an integrally-formed inductor. BACKGROUND

[0002] The integrally-formed inductor is widely applied in DC-DC converters due to small volume, low cost, large saturated magnetic flux density, small leakage and high automation. The integrally-formed inductor is divided into room temperature pressing process and hot pressing process according to the difference in pressing temperature. The hot pressing process is applied in high-reliability application scenarios due to low forming pressure and small internal defects of the inductor in the pressing process. However, the traditional hot pressing process adopts a hollow coil, and the coil will be inclined in the subsequent hot pressing process, thereby causing the performance of the formed inductor to deteriorate. Therefore, a preforming technology for the magnetic center column of the inductor is developed, which can effectively avoid the inclination of the coil in the pressing process, thereby effectively improving the performance and reliability of the inductor. However, the existing magnetic center column is usually composed of a single magnetic core, which cannot meet the inductance value requirements under light load and heavy load, thereby affecting the performance of the inductor. CONTENT OF THE UTILITY MODEL

[0003] Therefore, the present application provides an integrally-formed inductor to improve the performance of the inductor.

[0004] The present application provides an integrally-formed inductor, which comprises a magnetic center column and a coil, the coil is arranged on the outer side of the magnetic center column, wherein the magnetic center column comprises at least one first magnetic core and at least one second magnetic core, the first magnetic core and the second magnetic core are alternately stacked, the relative permeability of the first magnetic core is smaller than that of the second magnetic core, the product of the saturation magnetic flux density of the first magnetic core and the cross-sectional area of the first magnetic core is S1, the product of the saturation magnetic flux density of the second magnetic core and the cross-sectional area of the second magnetic core is S2, and S1 is greater than or equal to 1.5S2.

[0005] In some embodiments, the relative permeability of the first magnetic core is 10-150, and the relative permeability of the second magnetic core is greater than 1000.

[0006] In some embodiments, the thickness of the second magnetic core is 0.5-5% of the thickness of the first magnetic core.

[0007] In some embodiments, the magnetic center column further comprises at least one third magnetic core, the relative permeability of the third magnetic core is different from that of the first magnetic core and the second magnetic core, the third magnetic core is arranged between the first magnetic core and the second magnetic core, or the third magnetic core is connected to one side of the first magnetic core away from the second magnetic core, or the third magnetic core is connected to one side of the second magnetic core away from the first magnetic core.

[0008] In some embodiments, the sum of the thickness of the third magnetic core and the thickness of the second magnetic core is 0.5-5% of the thickness of the first magnetic core.

[0009] In some embodiments, the relative magnetic permeability of the third magnetic core is greater than 1000, the product of the saturation magnetic flux density of the third magnetic core and the cross-sectional area of the third magnetic core is S3, and S3≤0.75S1 is satisfied.

[0010] In some embodiments, the relative magnetic permeability of the third magnetic core is 1, and the thickness of the third magnetic core is 0.5-1% of the thickness of the magnetic column.

[0011] In some embodiments, the inductor further comprises a magnetic plate, the magnetic column is connected with the magnetic plate, the coil is wound outside the magnetic column and abuts against the magnetic plate, and the cross-sectional area of the magnetic plate is greater than the cross-sectional area of the first magnetic core and the second magnetic core.

[0012] In some embodiments, the relative magnetic permeability of the magnetic plate is 10-150.

[0013] In some embodiments, the thickness of the coil is the same as the thickness of the magnetic column, and the inductor further comprises a cladding layer arranged on the magnetic plate and wrapping the magnetic column and the coil, and the cross-sectional area of the cladding layer is the same as the cross-sectional area of the magnetic plate.

[0014] The present application provides an integrally formed inductor, comprising a magnetic column and a coil, the coil being wound outside the magnetic column, wherein the magnetic column comprises at least one first magnetic core and at least one second magnetic core, the first magnetic core and the second magnetic core being arranged in an alternating stack, the relative magnetic permeability of the first magnetic core being less than the relative magnetic permeability of the second magnetic core, the product of the saturation magnetic flux density of the first magnetic core and the cross-sectional area of the first magnetic core being S1, the product of the saturation magnetic flux density of the second magnetic core and the cross-sectional area of the second magnetic core being S2, and S1≥2S2 being satisfied, so as to improve the inductor performance. BRIEF DESCRIPTION OF DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0016] Figure 1 is a schematic diagram of the three-dimensional structure of the integrally formed inductor of the present application;

[0017] Figure 2 is a schematic diagram of the three-dimensional structure of the magnetic column in Figure 1 ​

[0018] Figure 3 yes Figure 1 Schematic diagram of the first three-dimensional structure of the magnetic center column and the coil;

[0019] Figure 4 yes Figure 1 Schematic diagram of the second three-dimensional structure of the magnetic center column and the coil;

[0020] Figure 5 Schematic diagram of current and inductance curves of an inductor in the prior art and an inductor provided in this application;

[0021] Figure 6 Schematic diagram of current and magnetic field strength curves of an inductor in the prior art and an inductor provided in this application.

[0022] Reference numerals:

[0023] 10. Inductor; 100. Magnetic center column; 110. First magnetic core; 120. Second magnetic core; 130. Third magnetic core; 200. Coil; 300. Covering layer; 400. Magnetic plate. DETAILED DESCRIPTION

[0024] The following, in conjunction with the accompanying drawings, clearly and completely describes the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of this application. In the absence of conflict, the following embodiments and their technical features can be combined with each other.

[0025] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined. In the description of this application, the meaning of "several" is at least one, such as one, two, etc., unless otherwise clearly and specifically defined.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. As used herein, the terms "connected," "coupled," "electrically connected," and "electrically coupled" include any direct or indirect electrical or structural connection between the things connected, coupled or electrically connected or coupled. Thus, if a first device is electrically connected / coupled to a second device, that first device can be directly electrically / structurally connected to the second device, or electrically / structurally connected to the second device through other devices or connection means.

[0027] The application provides an integrally formed inductor, comprising a magnetic core and a coil, the coil being wound around the outside of the magnetic core, wherein the magnetic core comprises at least one first magnetic core and at least one second magnetic core, the first magnetic core and the second magnetic core being alternately stacked, the relative permeability of the first magnetic core being less than that of the second magnetic core, the product of the saturation magnetic flux density of the first magnetic core and the cross-sectional area of the first magnetic core being S1, the product of the saturation magnetic flux density of the second magnetic core and the cross-sectional area of the second magnetic core being S2, and S1≥1.5S2 being satisfied.

[0028] In the application, the magnetic core is composed of at least one first magnetic core and at least one second magnetic core, and the relative permeability of the first magnetic core is set to be less than that of the second magnetic core, and the product of the saturation magnetic flux density of the first magnetic core and the cross-sectional area of the first magnetic core is set to be greater than or equal to 1.5 times the product of the saturation magnetic flux density of the second magnetic core and the cross-sectional area of the second magnetic core, so that in the light load state, the second magnetic core does not saturate, and in the light load state, the relative permeability of the second magnetic core is very large, and the relative permeability of the first magnetic core is relatively small and can be ignored, thereby reducing the total magnetic resistance of the magnetic core in the light load state, thereby improving the inductance in the light load state, and in the load state, the second magnetic core saturates, at this time, the second magnetic core can be equivalent to an air gap, used to bear most of the magnetic pressure drop, thereby reducing the magnetic field strength of the first magnetic core, thereby improving the inductance in the heavy load state, that is, reducing the risk of deformation of the coil, while improving the inductance in the heavy load state and the light load state, thereby improving the performance of the inductor.

[0029] Please refer to Figures 1-3 , Figure 1 is a schematic diagram of the three-dimensional structure of the integrally formed inductor of the application; Figure 2 is Figure 1 a schematic diagram of the three-dimensional structure of the magnetic core in Figure 3 is Figure 1Schematic diagram of the first three-dimensional structure of the magnetic center column and the coil in the embodiment. The present application provides an integrated molded inductor 10, including a magnetic center column 100 and a coil 200, wherein the coil 200 is wound on the outside of the magnetic center column 100, wherein the magnetic center column 100 includes at least one first magnetic core 110 and at least one second magnetic core 120, wherein the first magnetic core 110 and the second magnetic core 120 are alternately stacked, the relative magnetic permeability of the first magnetic core 110 is less than the relative magnetic permeability of the second magnetic core 120, the product of the saturation magnetic flux density of the first magnetic core 110 and the cross-sectional area of ​​the first magnetic core 110 is S1, the product of the saturation magnetic flux density of the second magnetic core 120 and the cross-sectional area of ​​the second magnetic core 120 is S2, and S1 ≥ 1.5S2 is satisfied. Specifically, the coil 200 can be formed by winding enameled copper wire, Litz wire, silk-wrapped wire or film-wrapped wire, and the coil 200 is sleeved on the outside of the magnetic column 100; the magnetic column 100 is composed of a first magnetic core 110 and a second magnetic core 120. The number of the first magnetic core 110 can be 1, 3, 5 or 6, and the number of the second magnetic core 120 can be 1, 3, 5 or 6. In this embodiment, the number of the second magnetic core 120 is 1 and the number of the first magnetic core 110 is 2 as an example for explanation. The second magnetic core 120 is sandwiched between the two first magnetic cores 110; the material forming the first magnetic core 110 includes at least one of FeSiAl, FeSi, FeNi, FeSiCr, carbonyl powder, amorphous powder or nanocrystalline powder, but is not limited thereto. The plane shape of the first magnetic core 110 can be circular, square, triangular or hexagonal, etc. In this embodiment, the planar shape of the first magnetic core 110 is circular as an example for description; the material forming the second magnetic core 120 includes at least one of ferrite material, amorphous block and nanocrystalline block, but is not limited thereto. The planar shape of the second magnetic core 120 can be circular, square, triangular or hexagonal, etc. In this embodiment, the planar shape of the second magnetic core 120 is circular as an example for description; the relative magnetic permeability of the first magnetic core 110 is less than the relative magnetic permeability of the second magnetic core 120, and the product of the saturation magnetic flux density of the first magnetic core 110 and the cross-sectional area of ​​the first magnetic core 110 is greater than or equal to 1.5 times the product of the saturation magnetic flux density of the second magnetic core 120 and the cross-sectional area of ​​the second magnetic core 120. Optionally, S1 can be 1.5S2, 2S2, 2.3S2, 2.75S2, 3.15S2, 3.68S2 or 4S2, etc. It should be noted that the cross-sectional area here refers to the effective cross-sectional area of ​​the magnetic center column 100 , that is, the effective cross-sectional area of ​​the area around the outer side of the magnetic center column 100 where the coil 200 is wound.

[0030] In the present application, the magnetic core 100 is composed of at least one first magnetic core 110 and at least one second magnetic core 120, and the relative permeability of the first magnetic core 110 is set to be less than the relative permeability of the second magnetic core 120, and the product of the saturation magnetic flux density of the first magnetic core 110 and the cross-sectional area of the first magnetic core 110 is set to be greater than or equal to 1.5 times the product of the saturation magnetic flux density of the second magnetic core 120 and the cross-sectional area of the second magnetic core 120, so that in the light load state, the second magnetic core 120 does not saturate, and the relative permeability of the second magnetic core 120 is very large, and the relative permeability of the first magnetic core 110 is relatively small and can be ignored, thereby reducing the total magnetic resistance of the magnetic core 100 in the light load state, thereby improving the inductance in the light load state, and reducing the ripple in the light load state, and in the load state, the second magnetic core 120 is saturated, at this time the second magnetic core 120 can be equivalent to an air gap, used to bear most of the magnetic pressure drop, thereby reducing the magnetic field strength of the first magnetic core 110, thereby improving the inductance in the heavy load state, without replacing the magnetic core with higher saturation magnetic flux density to worsen the eddy current loss, or increasing the cross-sectional area of the magnetic core 100 or the number of turns of the coil 200 to sacrifice the size of the inductor 10 or the DCR of the coil 200, while reducing the risk of deformation of the coil 200, improving the inductance of the inductor 10 in the heavy load state and the light load state, and improving the saturation characteristics of the inductor 10, thereby improving the performance of the inductor 10.

[0031] In an embodiment, the relative permeability of the first magnetic core 110 is 10-150, and the relative permeability of the second magnetic core 120 is greater than 1000. Specifically, the relative permeability of the first magnetic core 110 can be 10, 14.6, 26.8, 37.1, 50, 67, 85, 120, 137, 148 or 150, and the relative permeability of the second magnetic core 120 can be 1001, 1089, 1100, 1500, 1800, 1900 or 1974, so that the risk of deformation of the coil 200 is reduced, and the inductance of the inductor 10 in the heavy load state and the light load state is further improved, thereby improving the performance of the inductor 10.

[0032] In an embodiment, the thickness of the second magnetic core 120 is 0.5-5% of the thickness d1 of the first magnetic core 110. Specifically, the thickness of the second magnetic core 120 can be 0.5%, 0.74%, 1.3%, 2.6%, 3.7%, 4.9% or 5% of the thickness d1 of the first magnetic core 110, so that the inductance of the second magnetic core 120 in the heavy load state is higher, thereby further improving the performance of the inductor 10.

[0033] In an embodiment, the inductor 10 further comprises a magnetic plate 400, the magnetic column 100 is connected with the magnetic plate 400, the coil 200 is arranged outside the magnetic column 100 and abuts against the magnetic plate 400, the cross-sectional area of the magnetic plate 400 is larger than the cross-sectional area of the first magnetic core 110 and the second magnetic core 120, that is, in the direction of the first magnetic core 110 towards the magnetic plate 400, the orthographic projection of the first magnetic core 110 and the second magnetic core 120 is within the orthographic projection of the magnetic plate 400, so that the coil 200 can be wrapped inside the magnetic powder.

[0034] In an embodiment, the relative magnetic permeability of the magnetic plate 400 is 10-150, that is, the magnetic plate 400 is composed of the first magnetic core 110, that is, the material forming the magnetic plate 400 is the same as the material forming the first magnetic core 110, and the material of the magnetic plate 400 comprises at least one of ferrite material, amorphous block and nanocrystalline block, but is not limited thereto.

[0035] In an embodiment, the thickness of the coil 200 is the same as the thickness D of the magnetic column 100, the inductor 10 further comprises a cladding layer 300 arranged on the magnetic plate 400 and wrapping the magnetic column 100 and the coil 200, the cross-sectional area of the cladding layer 300 is the same as the cross-sectional area of the magnetic plate 400, so as to wrap the coil 200 on the magnetic plate 400, avoiding damage of the inductor during operation.

[0036] Please refer to Figure 4 , Figure 4 is Figure 1 the second three-dimensional structure diagram of the magnetic column and the coil in Figure 4 and Figure 3The structural difference in the inductor 10 is that the magnetic central column 100 further comprises at least one third magnetic core 130, the relative permeability of the third magnetic core 130 is different from the relative permeability of the first magnetic core 110 and the second magnetic core 120, the third magnetic core 130 is arranged between the first magnetic core 110 and the second magnetic core 120, or the third magnetic core 130 is connected to the side of the first magnetic core 110 away from the second magnetic core 120, or the third magnetic core 130 is connected to the side of the second magnetic core 120 away from the first magnetic core 110. In this embodiment, the third magnetic core 130 is arranged on the side of the first magnetic core 110 away from the magnetic plate 400. A layer of the first magnetic core 110 is formed on the side of the third magnetic core 130 away from the magnetic plate 400, so that in the light load state, because the relative permeability of the second magnetic core 120 and the relative permeability of the third magnetic core 130 are greater than the relative permeability of the first magnetic core 110, the magnetic circuit in the inductor 10 can be controlled by the second magnetic core 120 and the third magnetic core 130, so that the inductor 10 has a higher inductance in the light load state. At the same time, in the heavy load state, when the second magnetic core 120 and the third magnetic core 130 are saturated, they can act as air gaps, so that in the heavy load state, the second magnetic core 120 and the third magnetic core 130 are mainly used to bear the secondary voltage drop, reducing the magnetic field strength at the first magnetic core 110, thereby improving the inductance in the heavy load state. That is, the inductor 10 can reduce the risk of deformation of the coil 200 while improving the inductance of the inductor 10 in the heavy load state and the light load state, improving the saturation characteristics of the inductor 10, and thereby improving the performance of the inductor 10.

[0037] In an embodiment, the sum of the thickness of the third magnetic core 130 and the thickness of the second magnetic core 120 is 0.5-5% of the thickness d1 of the first magnetic core 110. Specifically, the sum of the thickness of the third magnetic core 130 and the thickness of the second magnetic core 120 can be 0.5%, 0.74%, 1.3%, 2.6%, 3.7%, 4.9% or 5% of the thickness d1 of the first magnetic core 110, etc., to further improve the inductance in the heavy load state, thereby further improving the performance of the inductor 10.

[0038] In an embodiment, the relative permeability of the third magnetic core 130 is greater than 10-150, the product of the saturation magnetic flux density of the third magnetic core 130 and the cross-sectional area of the third magnetic core 130 is S3, and S3≤0.75S1 is satisfied. Specifically, the product S3 of the saturation magnetic flux density of the third magnetic core 130 and the cross-sectional area of the third magnetic core 130 is less than or equal to 0.75 times the product S1 of the saturation magnetic flux density of the first magnetic core 110 and the cross-sectional area of the first magnetic core 110, the third magnetic core 130 is composed of a magnetic material, and the relative permeability of the third magnetic core 130 can be 1001, 1089, 1100, 1500, 1800, 1900, or 1974, so as to reduce the risk of deformation of the coil 200 while further improving the inductance value of the inductor 10 under heavy load and light load, thereby improving the performance of the inductor 10.

[0039] In an embodiment, the relative permeability of the third magnetic core 130 is 1, and the thickness of the third magnetic core 130 is 0.5-1% of the thickness of the magnetic core 100. Specifically, the third magnetic core 130 is formed of a non-magnetic material, and the thickness of the third magnetic core 130 is 0.5%, 0.64%, 0.75%, 0.89%, 0.98%, or 1% of the thickness D of the magnetic core 100, so as to reduce the risk of deformation of the coil 200 while further improving the inductance value of the inductor 10 under heavy load and light load, thereby improving the performance of the inductor 10.

[0040] Please refer to Figure 5 , Figure 5 is the current and inductance value curve of the inductor 10 in the prior art and the inductor 10 provided by the present application. It should be noted that the magnetic core 100 of the inductor 10 in the prior art is composed of a single magnetic core, Figure 5 W1 in the prior art is the current and inductance value curve of the inductor, Figure 5 W2 is the current and inductance value curve of the inductor provided by the present application. From Figure 5 it can be seen that the inductor 10 of the present application is provided by sandwiching the second magnetic core 120 between the two first magnetic cores 110, and the relative permeability of the second magnetic core 120 is much greater than the relative permeability u1 of the first magnetic core under light load, so it has a higher inductance value. At the same time, under heavy load, the second magnetic core 120 is saturated and acts as an air gap, so it bears the main magnetic pressure drop under heavy load, and the magnetic field strength at the first magnetic core 110, thereby improving the inductance value under heavy load. The magnetic core 100 in the present application does not need to replace the magnetic core with higher saturation magnetic flux density to cause the deterioration of eddy current loss, nor does it need to increase the cross-sectional area or the number of turns of the coil 200 to sacrifice the size of the inductor 10 or the DCR of the coil 200, i.e. according to the simulation results of Figure 5 the magnetic core 100 structure of the present application can improve the inductance value under light and heavy load, and improve the saturation characteristics of the inductor 10.

[0041] Please refer to Figure 6 , Figure 6 is the current and magnetic field strength curve of the inductor in the prior art and the inductor provided by the present application. It should be noted that, Figure 6 H_avg-S1-1 is the average magnetic field strength of the magnetic core 100 S1-1 cross section of the inductor 10 in the prior art, H_avg_s2-1 is the average magnetic field strength of the first magnetic core 110 S2-1 cross section of the inductor 10 in the present application, and H_avg_s2-2 is the average magnetic field strength of the second magnetic core 120 S2-2 of the inductor 10 in the present application, which is Figure 6 It can be seen that under light load, H_avg_s2-2 is very small, and the second magnetic core 120 does not saturate, at this time the relative permeability of the second magnetic core 120 is very large, so the light load inductance value of the inductor 10 of the present application is higher than that of the inductor 10 in the prior art, under heavy load, H_avg_s2-2 increases rapidly, and the second magnetic core 120 bears the main magnetic pressure drop, at this time H_avg_s2-1 of the inductor 10 in the present application is smaller than H_avg-S1-1 of the inductor 10 in the prior art, so the inductance value of the inductor 10 of the present application is higher than that of the inductor 10 in the prior art under heavy load, that is, the design of the magnetic core 100 of the present application can reduce the risk of deformation of the coil 200 while improving the inductance value of the inductor 10 under heavy load and light load, thereby improving the performance of the inductor 10.

[0042] The above is only an embodiment of the present application, and does not limit the patent scope of the present application, and any equivalent structure or equivalent flow transformation made by using the content of the present application specification and drawings, such as the mutual combination of technical features between embodiments, or direct or indirect application in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. An integrally formed inductor, characterized in that: It includes a magnetic center column and a coil, wherein the coil is wound on the outside of the magnetic center column, wherein the magnetic center column includes at least one first magnetic core and at least one second magnetic core, the first magnetic core and the second magnetic core are alternately stacked, the relative magnetic permeability of the first magnetic core is less than the relative magnetic permeability of the second magnetic core, the product of the saturation magnetic flux density of the first magnetic core and the cross-sectional area of ​​the first magnetic core is S1, the product of the saturation magnetic flux density of the second magnetic core and the cross-sectional area of ​​the second magnetic core is S2, and S1≥1.5S2 is satisfied.

2. The one-piece molded inductor according to claim 1, characterized in that: The relative magnetic permeability of the first magnetic core is 10-150, and the relative magnetic permeability of the second magnetic core is greater than 1000.

3. The one-piece molded inductor according to claim 1, characterized in that: The thickness of the second magnetic core is 0.5-5% of the thickness of the first magnetic core.

4. The one-piece molded inductor according to claim 1, characterized in that: The magnetic center column also includes at least one third magnetic core, the relative magnetic permeability of the third magnetic core is different from the relative magnetic permeability of the first magnetic core and the second magnetic core, and the third magnetic core is arranged between the first magnetic core and the second magnetic core, or the third magnetic core is connected to the side of the first magnetic core facing away from the second magnetic core, or the third magnetic core is connected to the side of the second magnetic core facing away from the first magnetic core.

5. The one-piece molded inductor according to claim 4, characterized in that: The sum of the thickness of the third magnetic core and the thickness of the second magnetic core is 0.5-5% of the thickness of the first magnetic core.

6. The one-piece molded inductor according to claim 4, characterized in that: The relative magnetic permeability of the third magnetic core is greater than 1000, the product of the saturation magnetic flux density of the third magnetic core and the cross-sectional area of ​​the third magnetic core is S3, and S3≤0.75S1 is satisfied.

7. The one-piece molded inductor according to claim 5, characterized in that: The relative magnetic permeability of the third magnetic core is 1, and the thickness of the third magnetic core is 0.5-1% of the thickness of the magnetic center column.

8. The integrally formed inductor according to claim 1, wherein: The inductor further includes a magnetic plate, the magnetic center column is connected to the magnetic plate, the coil is wound around the outside of the magnetic center column and abuts against the magnetic plate, and the cross-sectional area of ​​the magnetic plate is larger than the cross-sectional areas of the first magnetic core and the second magnetic core.

9. The integrally formed inductor according to claim 8, wherein: The relative magnetic permeability of the magnetic plate is 10-150.

10. The integrally formed inductor according to claim 8, wherein: The thickness of the coil is the same as that of the magnetic center column. The inductor further includes a covering layer arranged on the magnetic plate and wrapping the magnetic center column and the coil. The cross-sectional area of ​​the covering layer is the same as that of the magnetic plate.

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