A magnetic core structure and inductor

Abstract

The present invention discloses a magnetic core structure and an inductor. The structure comprises a magnetic core having at least two air gaps formed therein, the sum of the widths of all the air gaps being equal to the width of a single air gap formed therein. By reducing the relative width of the air gaps, leakage flux is reduced, core losses are lowered, and the amount of leakage flux cut by the coil on the core is reduced, thereby increasing the inductance of the inductor. The invention also provides an inductor comprising a magnetic core and a coil, the coil being wound around a portion of the magnetic core.

Description

Technical Field

[0001] The present invention belongs to the field of inductance, and in particular relates to a magnetic core structure and an inductor. Background Art

[0002] Inductors are components that convert electrical energy into magnetic energy and store it, and are widely used in various circuit structures. Inductors generally consist of a bobbin, a magnetic core, and a coil. The magnetic core is a high-frequency magnetic material with high magnetic permeability and high magnetic flux density.

[0003] In which, a winding portion is provided on the skeleton, and a hollow channel is provided on the winding portion along the axial direction. The coil is wound on the winding portion, and at least part of the magnetic core is inserted into the hollow channel. An air gap is provided on this part of the magnetic core. The purpose of providing the air gap on this part of the magnetic core is to prevent magnetic saturation of the magnetic core. However, the inductor generates leakage flux at the air gap; since only one air gap is generally provided on this part of the magnetic core, the air gap has a large width, resulting in more leakage flux here, which on the one hand increases the loss of the magnetic core, and on the other hand increases the cutting of the leakage flux of the magnetic core by the coil, increases the eddy current loss of the coil, and thus reduces the inductance of the inductor. Summary of the Invention

[0004] The first technical problem to be solved by the present invention is to overcome the deficiencies in the prior art and provide a magnetic core structure and an inductor to achieve the purpose of reducing leakage flux, reducing core loss and reducing the cutting of leakage flux of the magnetic core by the coil, thereby reducing eddy current loss of the coil.

[0005] In order to solve the above technical problems, the basic concept of the technical solution adopted by the present invention is:

[0006] The present invention provides a magnetic core structure, comprising a magnetic core. The magnetic core is provided with at least two air gaps, and the sum of the widths of all the air gaps is equal to the width of the air gap when only one air gap is provided on the magnetic core.

[0007] Furthermore, two magnetic columns are provided on opposite sides of the magnetic core, and an intermediate magnetic column is provided on the magnetic core between the two magnetic columns. At least two air gaps are provided on the intermediate magnetic column, and the sum of the widths of all the air gaps is equal to the width of the air gap when one air gap is provided on the intermediate magnetic column.

[0008] Furthermore, the magnetic core includes two sub-cores, each sub-core including an outer ring magnetic core and a middle column arranged on the inner side of the outer ring magnetic core; the two outer ring magnetic cores are opposite and in contact with each other to form two magnetic columns, the two middle columns are opposite and spaced apart to form an intermediate magnetic column, an air gap in the intermediate magnetic column is formed between the axial end faces of the two middle columns, and other air gaps are respectively opened on the two middle columns.

[0009] Furthermore, the two sub-magnetic cores have the same size and are both E-shaped, an intermediate air gap of the intermediate magnetic column is formed between the axial end faces of the two intermediate columns, and the air gaps provided on each intermediate column are side air gaps.

[0010] Furthermore, the width of the middle air gap is greater than or equal to the width of the side air gaps, and the intervals between the air gaps are equal.

[0011] Furthermore, at least two air gaps separate the middle magnetic column into several sub-middle magnetic columns, an air gap is formed between the axial end faces of two adjacent sub-middle magnetic columns, an insulating member is inserted into each air gap, and the insulating member is respectively fitted and connected to the axial end faces of the two sub-middle magnetic columns.

[0012] Furthermore, the insulating member is a first plastic sheet, each first plastic sheet is inserted into a corresponding air gap, and opposite sides thereof are respectively fitted and connected to the axial end faces of the two sub-middle magnetic columns.

[0013] Furthermore, a second plastic sheet extending along the axial direction of the middle magnetic column is provided on the middle magnetic column. The second plastic sheet is arranged in contact with the middle magnetic column. Each first plastic sheet is vertically connected to the second plastic sheet. All first plastic sheets are arranged on the same side of the second plastic sheet.

[0014] Furthermore, heat sinks are provided on opposite sides of the first plastic sheet, one side of the heat sink is connected to the axial end surface of the middle magnetic column, and the other side is connected to one side of the first plastic sheet;

[0015] Preferably, the heat sink is a glue layer formed by adhering the first plastic sheet to the axial end surfaces of the two sub-middle magnetic columns.

[0016] The present invention also provides an inductor, comprising a coil and a magnetic core structure provided by the above technical solution, wherein the coil is wound around a portion of the magnetic core in the magnetic core structure.

[0017] After adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art.

[0018] 1. At least two air gaps are provided on the magnetic core, and the sum of the widths of all the air gaps is equal to the width of the air gap when one air gap is provided on the magnetic core. The relative width of the air gap is reduced, thereby reducing the leakage flux, thereby reducing the magnetic loss of the magnetic core structure, and reducing the cutting of the leakage flux of the magnetic core by the coil, reducing the eddy current loss of the coil, thereby increasing the inductance of the inductor.

[0019] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings, as part of this disclosure, are intended to provide a further understanding of the disclosure. The exemplary embodiments of the disclosure and their descriptions are intended to explain the disclosure and do not constitute undue limitations thereon. Obviously, the drawings described below are merely examples, and those skilled in the art can derive other drawings based on these drawings without inventive effort.

[0021] Figure 1 is a structural schematic diagram of a magnetic core structure provided by one embodiment of the present invention;

[0022] Figure 2 Schematic diagram of the distribution of main magnetic flux and leakage magnetic flux on a magnetic core structure provided by one embodiment of the present invention;

[0023] Figure 3 1 is a schematic structural diagram of a magnetic core structure with an insulating member provided in an air gap according to an embodiment of the present invention.

[0024] Figure 4 is a schematic structural diagram of an inductor provided in an embodiment of the present invention;

[0025] Figure 5 is a cross-sectional view of an inductor provided by an embodiment of the present invention;

[0026] Figure 6 Schematic diagram of the structure of the skeleton of the inductor provided by an embodiment of the present invention.

[0027] In the figure: 1-skeleton; 11-winding part; 111-hollow channel; 12-coil pin; 2-magnetic core; 21-sub-magnetic core; 211-outer ring magnetic core; 212-middle column; 22-magnetic column; 23-middle magnetic column; 231-sub-middle magnetic column; 3-spacing; 31-first spacing; 32-second spacing; 4-first protrusion; 41-first extension; 5-second protrusion; 51-second extension; 6-limiting groove; 7-air gap; 71-middle air gap; 72-side air gap; 8-insulating member; 81-first plastic sheet; 9-heat sink; 91-glue layer.

[0028] It should be noted that these drawings and textual descriptions are not intended to limit the conceptual scope of the present invention in any way, but rather to illustrate the concept of the present invention for those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The following embodiments are used to illustrate the present invention but are not used to limit the scope of the present invention.

[0030] In the description of the present invention, it should be noted that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "inside", "outside", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the present invention.

[0031] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; and direct or indirect connections through an intermediary. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0032] Example

[0033] like Figure 1 、 Figure 2 as well as Figure 3 As shown, the present invention provides a magnetic core structure, including a magnetic core 2 , with at least two air gaps 7 formed on the magnetic core 2 , and the sum of the widths of all the air gaps 7 is equal to the width of the air gap when only one air gap 7 is formed on the magnetic core 2 .

[0034] In an embodiment of the present invention, a plurality of air gaps 7 are provided on the magnetic core 2, and the sum of the widths of all the air gaps 7 is equal to the width of a single air gap provided on the magnetic core 2. Reducing the relative width of the air gaps 7 reduces the leakage flux at the air gaps, thereby reducing the magnetic loss of the magnetic core structure. Furthermore, since the leakage flux is reduced, the inductor coil can reduce the amount of leakage flux cut into the magnetic core, reducing the eddy current loss of the coil, thereby achieving the purpose of increasing the inductance while maintaining the same number of coil turns. Furthermore, while increasing the inductance, the material of the magnetic core remains unchanged, thereby reducing production costs.

[0035] It should be noted that, for the existing magnetic core structure, only one air gap is provided on the magnetic core 2, and the air gap has a certain width. In the present application, at least two air gaps 7 are provided on the magnetic core 2, wherein the sum of the widths of the plurality of air gaps 7 is equal to the width of one air gap provided on the magnetic core in the prior art; for example, if the width of one air gap in the prior art is 8 mm, then the sum of the widths of the plurality of air gaps in the present application is 8 mm.

[0036] like Figure 2 As shown, in Figure 2 The figure shows the distribution of the main magnetic flux and leakage magnetic flux on the magnetic core structure; an air gap is provided on the magnetic core. When the coil is energized, a current flows through the coil. When a current flows through the coil, a magnetic field is formed in the space around the coil. Since the magnetic core has better magnetic conductivity than air, most of the magnetic flux forms a loop along the magnetic core and the air gap. This part of the magnetic flux becomes the main magnetic flux. Another part of the magnetic flux does not pass through the air gap, but forms a loop through the air. This part becomes the leakage magnetic flux.

[0037] like Figure 1 、 Figure 2 as well as Figure 3As shown, in an embodiment of the present invention, two magnetic pillars 22 are provided on opposite sides of the magnetic core, and an intermediate magnetic pillar 23 is provided on the magnetic core between the two magnetic pillars 22. At least two air gaps are provided on each of the two magnetic pillars and the intermediate magnetic pillar 23, and the sum of the widths of all the air gaps is equal to the width of the air gap when one air gap is provided on the intermediate magnetic pillar.

[0038] In the embodiment of the present invention, the magnetic core is square, and the middle magnetic column 23 is located between the two magnetic columns 22 and is arranged parallel to the two magnetic columns 22. There is a clamping space between the middle magnetic column 23 and one magnetic column, and another clamping space between the middle magnetic column 23 and the other magnetic column 22. The two clamping spaces are used to cooperate with the skeleton in the inductor to achieve assembly of the magnetic core and the skeleton.

[0039] The two magnetic columns 22 and the middle magnetic column 23 are both in the shape of a cuboid; in other embodiments, the shapes of the magnetic columns 22 and the middle magnetic column 23 can also be changed to cylindrical, polygonal prism or irregular cylindrical shapes according to actual needs;

[0040] Specifically, at least two air gaps 7 are provided on the middle magnetic column 23, and at least two air gaps 7 are arranged at intervals along the axial direction of the middle magnetic column 23. The sizes of the air gaps in the axial direction of the middle magnetic column 23 are equal or unequal. According to actual needs, the widths of the air gaps on the middle magnetic column 23 can be set to be equal or unequal, wherein the size of the air gap 7 in the axial direction of the middle magnetic column 23 is also the width of the air gap 7; the number of air gaps 7 provided on the middle magnetic column 23 can be provided according to actual needs; providing the air gap 7 on the middle magnetic column 23 of the magnetic core 2, that is, providing the air gap 7 in the middle part of the magnetic core 2, can further reduce the loss of the inductor and increase the inductance of the inductor.

[0041] In an embodiment of the present invention, the magnetic core 2 includes two sub-cores 21, each of which includes an outer ring magnetic core 211 and a middle column 212 arranged on the inner side of the outer ring magnetic core 211; the two outer ring magnetic cores 211 are opposite and in contact with each other to form two magnetic columns, and the two middle columns 212 are opposite and spaced apart to form an intermediate magnetic column 23. An air gap in the intermediate magnetic column 23 is formed between the axial end faces of the two middle columns 212, and other air gaps are respectively opened on the two middle columns 212.

[0042] In the embodiment of the present invention, two sub-cores 21 are arranged opposite to each other to form the magnetic core 2. Specifically, one side of the outer ring magnetic core 211 is open. The outer ring magnetic core 211 is annular and can be a square ring or a circular ring. Since the outer ring magnetic core 211 is annular, the outer ring magnetic core 211 has an inner side and an outer side. The center column 212 is located in the middle of the inner side of the outer ring magnetic core 211 and extends toward the opening of the outer ring magnetic core 211.

[0043] The two outer ring magnetic cores 211 are formed relative to each other and contact each other to form the outer frame of the magnetic core 2. The outer frame of the magnetic core 2 includes two magnetic columns 22. The axial end surfaces of the two middle columns 212 form an air gap in the middle magnetic column 23, and the other air gaps on the middle magnetic column 23 are opened on the two middle columns 212. For example, if three air gaps are opened on the middle magnetic column, the axial end surfaces of the two middle columns 212 form one air gap of the three air gaps, one middle column 212 is provided with another air gap of the three air gaps, and the other middle column 212 is provided with another air gap of the three air gaps.

[0044] like Figure 1 As shown, in the embodiment of the present invention, the two sub-cores 21 have the same size and are both E-shaped, and an intermediate air gap 71 of the intermediate magnetic column 23 is formed between the axial end surfaces of the two middle columns 212, and the air gap opened on each middle column 212 is a side air gap 72.

[0045] In the embodiment of the present invention, both sub-cores 21 are E-shaped. When the inductor magnetic potential is constant, the maximum magnetic potential of the E-shaped core is smaller. The smaller maximum magnetic potential is conducive to reducing the bypass magnetic flux, thereby reducing the eddy current loss of the inductor caused by the bypass magnetic flux.

[0046] Specifically, the outer ring magnetic core 211 includes two sub-magnetic columns arranged on both sides of the center column 212 and a connecting magnetic column connecting the two sub-magnetic columns. The two sub-magnetic columns and the center column 212 are perpendicular to the connecting magnetic column. One sub-magnetic column, the center column 212, and the connecting magnetic column form a clamping space, and the other sub-magnetic column, the center column 212, and the connecting magnetic column form another clamping space. The above two clamping spaces are used to cooperate with the skeleton of the inductor. The longitudinal length of the center column 212 is smaller than the longitudinal length of the sub-magnetic columns. Therefore, when the two outer ring magnetic cores 211 are opposite and in contact, an air gap can be formed between the two center columns 212.

[0047] Since the two sub-cores have the same size, the air gap formed by the two middle columns 212 facing each other is the air gap in the middle of the middle magnetic column, that is, the middle air gap 71 , and the air gaps at other positions of the middle magnetic column 23 are side air gaps 72 .

[0048] Specifically, the width of the middle air gap 71 is greater than or equal to the width of the side air gap 72, and the spacing between each air gap is equal; preferably, the width of the middle air gap 71 is greater than the width of the side air gap 72, so as to avoid the situation where the side air gap 72 is close to the two sides of the magnetic core 2 due to its large width, thereby causing increased damage to the magnetic core 2.

[0049] In the embodiment of the present invention, at least two air gaps separate the middle magnetic column into a plurality of sub-middle magnetic columns 231 . An air gap is formed between the axial end faces of two adjacent sub-middle magnetic columns 231 . An insulating member 8 is provided in each air gap. The insulating member 8 is respectively bonded to the axial end faces of the two sub-middle magnetic columns 231 .

[0050] In an embodiment of the present invention, the insulating member 8 is inserted into the air gap 7 to achieve a connection between two adjacent sub-intermediate magnetic columns 231, and the insulating member 8 has insulating properties and does not have a cutting effect on the main magnetic flux in the magnetic core; the insulating member 8 can be completely inserted into the air gap 7 or partially inserted into the air gap 7; in addition, the insulating member 8 can be made of a variety of materials and shapes as long as it has no cutting effect on the main magnetic flux in the magnetic core.

[0051] like Figure 3 As shown, in the embodiment of the present invention, the insulating member 8 is a first plastic sheet 81 , which is inserted into the corresponding air gap, and opposite sides of the first plastic sheet 81 are respectively fitted and connected with the axial end faces of the two sub-middle magnetic columns 231 .

[0052] In the embodiment of the present invention, the insulating member 8 is made of plastic and is in the form of a sheet. A first plastic sheet 81 is inserted into the air gap. One side surface of the first plastic sheet 81 is bonded to the axial end surface of one sub-intermediate magnetic column 231 , and the opposite side surface is bonded to the axial end surface of an adjacent sub-intermediate magnetic column 231 , thereby connecting two adjacent sub-intermediate magnetic columns 231 .

[0053] When the insulating member 8 is fully inserted into the air gap, the area of the side surface of the first plastic sheet 81 may be smaller than the area of the axial end surface of the sub-intermediate magnetic column 231, or may be equal to the area of the axial end surface of the intermediate magnetic column, as long as it is ensured that the two adjacent sub-intermediate magnetic columns 231 can be connected. Preferably, the area of the side surface of the first plastic sheet 81 is equal to the area of the axial end surface of the intermediate magnetic column, thereby increasing the connection strength between the two adjacent sub-intermediate magnetic columns 231.

[0054] Furthermore, a second plastic sheet extending along the axial direction of the middle magnetic column is provided on the middle magnetic column. The second plastic sheet is arranged in contact with the middle magnetic column 23. Each first plastic sheet 81 is vertically connected to the second plastic sheet. All first plastic sheets 81 are arranged on the same side of the second plastic sheet. The second plastic sheet integrates several first plastic sheets 81 to avoid the situation where several first plastic sheets 81 are easily lost, and several first plastic sheets 81 can be inserted into their corresponding air gaps at the same time, thereby improving insertion efficiency.

[0055] In the embodiment of the present invention, heat sinks 9 are provided on opposite sides of the first plastic sheet 81 . One side of the heat sink 9 is connected to the axial end surface of the sub-middle magnetic column 231 , and the other side is connected to one side of the first plastic sheet 81 .

[0056] In the embodiment of the present invention, the setting of the heat sink 9 enables the first plastic sheet 81 to be connected to the sub-middle magnetic column 231, thereby realizing the connection between two adjacent sub-middle magnetic columns 231. At the same time, the heat sink 9 can reduce the temperature of the magnetic core, facilitate heat dissipation, and further improve the saturation value.

[0057] like Figure 3As shown, in the embodiment of the present invention, the heat sink 9 is a glue layer 91 formed by adhering the first plastic sheet 81 to the axial end surfaces of the two sub-middle magnetic columns 231 .

[0058] In the embodiment of the present invention, the glue layer 91 is epoxy resin glue, and of course it can also be other types of materials that can play an adhesive role. At the same time, this material cannot have the function of magnetic permeability and must also have the function of heat dissipation.

[0059] The area of the side surface of the glue layer 91 may be smaller than the area of the side surface of the plastic sheet 81 and the area of the axial end surface of the sub-intermediate magnetic column 231, or may be equal to the area of the side surface of the plastic sheet 81 and the area of the axial end surface of the sub-intermediate magnetic column 231. Preferably, the area of the side surface of the glue layer 91 is equal to the area of the side surface of the plastic sheet 81 and the area of the axial end surface of the sub-intermediate magnetic column 231, thereby improving the connection strength between two adjacent sub-intermediate magnetic columns 231.

[0060] like Figure 4 As shown, the present invention provides an inductor, including a coil and a magnetic core structure provided by the above technical solution, wherein the coil is wound around a part of the magnetic core in the magnetic core structure.

[0061] Furthermore, if Figure 4 、 Figure 5 and Figure 6 As shown, the inductor further includes a skeleton 1, which has a winding portion, on which a coil is wound. The winding portion 11 is in an elongated shape. A hollow channel 111 is provided on the winding portion along the axial direction of the winding portion 11. The hollow channel 111 is in an elongated shape. Two openings are provided on opposite sides of the hollow channel 111. A center column 212 of one sub-core is axially inserted into the hollow channel 111 through one opening, and a center column 212 of another sub-core is axially inserted into the hollow channel 111 through the other opening, so that the two center columns 212 are relatively inserted into the hollow channel 111. Furthermore, one side wall of the winding portion 11 is inserted into the clamping space, and the other opposite side wall is inserted into the other clamping space, thereby achieving assembly of the magnetic core and the skeleton.

[0062] The center column 212 is inserted into the hollow channel 111, and a gap 3 is provided between the center column 212 and the hollow channel 111. The gap 3 is provided between the center column 212 and the hollow channel 111 so that the coil can be away from the leakage flux of the magnetic core 2, thereby minimizing the cutting of the leakage flux of the magnetic core 2 by the coil as much as possible, reducing the eddy current loss of the coil, and improving the inductance of the inductor; the number of coil turns is not increased or a more expensive magnetic core is used to reduce the eddy current loss of the coil, thereby reducing costs.

[0063] Specifically, the middle column 212 is a rectangular parallelepiped, and the middle column 212 has upper and lower end faces and left and right end faces. The middle column 212 is inserted into the hollow channel 111 from the center of the hollow channel 111, so that the upper and lower end faces, left and right end faces of the middle column 212 and the inner wall of the hollow channel are spaced apart. Since the shape of the axial cross section of the hollow channel 111 is various, the size of the spacing between the upper and lower end faces of the middle column 212 and the inner wall of the hollow channel 111 is different from the size of the spacing between the left and right end faces of the middle column 212 and the inner wall of the hollow channel 111. For example, Figure 5 As shown, the distance between the upper and lower end surfaces of the center column 212 and the inner wall of the hollow channel 111 is set to a first distance 31, and the distance between the left and right end surfaces of the center column 212 and the inner wall of the hollow channel 111 is set to a second distance 32. The size of the first distance 31 is equal to or not equal to the size of the second distance 32.

[0064] like Figure 6 As shown, further, first protrusions are provided on opposite sides of the top of the winding portion 11, and the first protrusions protrude axially outward relative to the winding portion, and second protrusions are provided on opposite sides of the bottom of the winding portion 11, and the second protrusions protrude axially outward relative to the winding portion. Part of the connecting magnetic column is clamped between the first protrusion 4 and the second protrusion 5, thereby realizing the assembly between the sub-core 21 and the winding portion 11. On the basis of ensuring that there is a distance between the upper and lower end faces and the left and right end faces of the middle column 212 and the hollow channel 111, the stability of the sub-core on the winding portion 11 is improved, thereby realizing the assembly between the entire core structure and the skeleton 1.

[0065] like Figure 6 As shown, further, a first extension portion 41 is provided on both sides of the left and right sides of the first protrusion 4, and the first extension portion 41 extends radially relative to the winding portion 11, and a second extension portion 51 is provided on both sides of the left and right sides of the second protrusion 5, and the second extension portion 51 extends radially relative to the winding portion 11. The sub-magnetic column and the remaining connecting magnetic columns are clamped in the clamping space formed by the first extension portion 41 and the second extension portion 51, which further enhances the assembly strength between the sub-core 21 and the winding portion 11 and improves the stability of the sub-core 21 on the winding portion 11.

[0066] like Figure 6 As shown, further, the two first protrusions 4 radially protrude relative to the winding portion 11 to form a first slot body, the two second protrusions 5 radially protrude relative to the winding portion 11 to form a second slot body, the winding portion 11 located between the first protrusions 4 and the second protrusions 5 is provided with four third protrusions radially protruding relative to the winding portion 11, and a third slot body is formed between the two opposing third protrusions. The first slot body, the second slot body and the two third slot bodies are connected in sequence to form a continuous limiting slot 6, which has a limiting effect on the coil wound on the winding portion 11 to avoid winding chaos of the coil during winding.

[0067] Furthermore, a plurality of coil pins 12 are provided on the second bump, and the plurality of coil pins 12 are arranged at intervals along the left-right direction. The coil wound on the winding portion 11 has an input end and an output end, and the input end and the output end of the coil are both provided on the coil pins 12 .

[0068] The inductor satisfies the following equation:

[0069] K=r 2 / (r+0.29*δ / π) 2 ;

[0070] γ=d / δ;

[0071] M=K*γ 1 / 2 ;

[0072] Where r is the radius of the core, δ is the width of the air gap, d is the distance between the coil and the core, K is the conversion coefficient of the core's magnetic flux, γ is the conversion coefficient of the edge magnetic flux loss, and M is the effective conversion coefficient of the magnetic flux. There are at least n air gaps on the core, and the width of each air gap is δ1, δ2, ..., δn, and satisfies δ1+δ2+...+δn=δ. The larger the M value, the greater the effective magnetic flux, and thus the greater the inductance.

[0073] It should be noted that, in the embodiment of the present invention, the coil is equivalent to being mounted on the middle magnetic column, and n air gaps are provided on the middle magnetic column. d can be considered as the average distance between the middle magnetic column and the coil.

[0074] Inductors designed using the above relationship can reduce losses by adjusting the values of δ and d, thereby increasing the effective value of the inductor magnetic flux φ. With the same number of coil turns, the inductance L can be increased. In other words, with other inductor parameters remaining unchanged, the same inductance L can be achieved with a lower number of turns than a typical inductor. For example, increasing the value of d can reduce coil eddy current losses and increase inductance.

[0075] The inductor's core consists of two E-shaped sub-cores of identical size, each with a radius of r = 5 mm. The radius of the sub-core is half the width of the middle magnetic column. The coil has 50 turns, and the total length of the winding portion 11 is 42 mm. With other conditions remaining unchanged, the inductors were divided into four groups for different δ and d values. The inductance of the corresponding inductors was measured, and the eddy current loss of the coils was calculated. The measurement results were compared with those of control groups 1 and 2. The results are shown in Table 1.

[0076] For control group 1, the middle magnetic column is divided into two sections, with the width of the air gap δ = 8 mm and the spacing d = 2 mm;

[0077] For control group 2, the middle magnetic column is divided into two sections, with the width of the air gap δ = 8 mm and the spacing d = 1 mm;

[0078] For group 1, the middle magnetic column is divided into two sections, with the width of the air gap δ = 8 mm and the spacing d = 4 mm;

[0079] For group 2, the middle magnetic column is divided into two sections, with the width of the air gap δ = 5 mm and the spacing d = 2.5;

[0080] For group 3, the middle magnetic column is divided into two sections, with the width of the air gap δ = 15 mm and the spacing d = 7.5;

[0081] For group 4, the middle magnetic column is divided into six sections, with five air gaps. The width of each air gap is δ1, δ2, δ3, δ4, and δ5, and satisfies δ1+δ2+δ3+δ4+δ5=8mm. δ1, δ2, δ3, and δ4 are the widths of the four side air gaps. Each middle column has two side air gaps, and δ5 is the width of the middle air gap. Among them, δ1=δ2=δ3=δ4=1mm, δ5=4mm, and the spacing d=4mm.

[0082] Table 1

[0083] Grouping δ(mm) d(mm) Inductance (μH) Eddy current loss (W) 1 8 4 89 1.8 2 5 2.5 85 2.15 3 15 7.5 81 2.85 4 - 4 92 1.5 Control 1 8 2 72 3.5 Control 2 8 1 70 4.5

[0084] In Table 1, compared with control group 1 and control group 2, it can be concluded that by reducing δ and / or increasing d, groups 1, 2, 3, and 4 all reduced eddy current loss and increased inductance;

[0085] Compared with group 1, it can be concluded that when d is the same and multiple air gaps are used, group 4 has the best effect in reducing eddy current loss and increasing inductance.

[0086] In summary, the way to increase the inductance of the inductor is:

[0087] Method 1: By setting a distance between the magnetic core 2 and the coil, the distance between the magnetic core 2 and the coil is increased, so that the leakage flux of the magnetic core is away from the coil, the cutting of the leakage flux of the magnetic core by the coil is reduced, and the eddy current loss of the coil is reduced;

[0088] Method 2: By providing at least two air gaps 7 on the magnetic core 2, the width of all air gaps 7 is equal to the width of the air gap when one air gap 7 is provided on the magnetic core 2, thereby reducing the relative width of the air gap, reducing the leakage flux on the magnetic core, thereby reducing the core loss, and reducing the cutting of the leakage flux of the magnetic core by the coil, thereby reducing the eddy current loss of the coil;

[0089] Method 3: The inductance of the inductor is increased by combining the method 1 of reducing the relative width of the air gap with the method 2 of increasing the distance between the magnetic core 2 and the coil to increase the degree of increase in inductance.

[0090] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as above in terms of a preferred embodiment, it is not intended to limit the present invention. Any technician familiar with this patent can make slight changes or modifications to equivalent embodiments using the above technical content without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the solution of the present invention.

Claims

1. An inductor comprising a magnetic core, characterized in that: Two magnetic columns are provided on opposite sides of the magnetic core, and an intermediate magnetic column is provided on the magnetic core between the two magnetic columns. At least two air gaps are provided on the intermediate magnetic column, and the sum of the widths of all the air gaps is equal to the width of the air gap when one air gap is provided on the intermediate magnetic column. The magnetic core includes two sub-cores, each sub-core including an outer ring core and a middle column disposed inside the outer ring core; the two outer ring cores are opposed to and in contact with each other to form two magnetic columns, the two middle columns are opposed to and spaced apart to form an intermediate magnetic column, an air gap is formed in the intermediate magnetic column between the axial end surfaces of the two middle columns, and other air gaps are respectively provided on the two middle columns; The two sub-cores are of the same size and are both E-shaped. The middle air gap of the middle magnetic column is formed between the axial end faces of the two middle columns, and the air gaps opened on each middle column are side air gaps. The inductor satisfies the following equation: K=r 2 / (r+0.29*δ / π) 2 ; γ=d / δ; M=K*γ 1 / 2 ; Where r is the radius of the core, δ is the width of the air gap, d is the distance between the coil and the core, K is the conversion factor of the magnetic flux of the core, γ is the conversion factor of the edge flux loss, and M is the effective conversion factor of the magnetic flux; Among them, the middle magnetic column is divided into six sections, and there are 5 air gaps on the magnetic core. The width of each air gap is δ1, δ2, δ3, δ4, and δ5, respectively, and satisfies δ1+δ2+δ3+δ4+δ5=8mm. δ1, δ2, δ3, and δ4 are the widths of the four side air gaps. Two side air gaps are set on each middle column, and δ5 is the width of the middle air gap. Among them, δ1=δ2=δ3=δ4=1mm, δ5=4mm, and the spacing d=4mm.

2. The inductor according to claim 1, wherein At least two air gaps separate the middle magnetic column into several sub-middle magnetic columns. An air gap is formed between the axial end faces of two adjacent sub-middle magnetic columns. An insulating member is inserted into each air gap. The insulating member is respectively connected to the axial end faces of the two sub-middle magnetic columns.

3. The inductor according to claim 2, wherein: The insulating members are first plastic sheets. Each first plastic sheet is inserted into a corresponding air gap, and opposite sides thereof are respectively fitted and connected to the axial end surfaces of the two sub-middle magnetic columns.

4. The inductor according to claim 3, wherein: A second plastic sheet extending along the axial direction of the middle magnetic column is provided on the middle magnetic column. The second plastic sheet is arranged in close contact with the middle magnetic column. Each first plastic sheet is vertically connected to the second plastic sheet. All first plastic sheets are arranged on the same side of the second plastic sheet.

5. The inductor according to claim 3 or 4, characterized in that: A heat sink is provided on opposite sides of the first plastic sheet. One side of the heat sink is connected to the axial end surface of the middle magnetic column, and the other side is connected to one side of the first plastic sheet.

6. The inductor according to claim 5, wherein: The heat sink is a glue layer formed by adhering the first plastic sheet to the axial end surfaces of the two sub-middle magnetic columns.

7. The inductor according to any one of claims 1 to 4, comprising a coil, characterized in that: The coil is wound around a portion of the magnetic core.

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