Coil components

Abstract

The present invention provides a coil component that can obtain a higher inductance even if a magnetic core including a metal magnetic body is used. The coil component includes: a main core having a middle leg and an outer leg, wherein the middle leg is wound with a coil body, and the outer leg is connected to the middle leg via a base; and a sub-core arranged to face the base with the middle leg interposed therebetween. There is a gap of a predetermined width between the middle leg and the sub-core, and the width of the gap between the middle leg and the sub-core is greater than the width of the gap between the outer leg and the sub-core.

Description

Technical Field

[0001] The present invention relates to a coil component used as, for example, an inductor. Background Art

[0002] Coil components used as inductors are used in various electronic circuits, such as DC-DC converters. As such an inductor, for example, an inductor disclosed in Patent Document 1 is known.

[0003] In order to increase the inductance, conventional inductors generally use a core made of ferrite material. However, inductors with a core made of ferrite material have a technical problem that the inductance and other characteristics are easily changed with temperature changes. In particular, recently, people have demanded inductors with small changes in characteristics at high temperatures of about 100 to 170 degrees Celsius.

[0004] Therefore, inductors having a core such as a core made of a metal magnetic body whose characteristics such as inductance change less with temperature changes have been studied. However, inductors having a core made of a metal magnetic body generally have a technical problem of having low inductance.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2009-16797 Summary of the invention

[0008] Technical problem to be solved by the invention

[0009] The present invention has been made in view of such actual circumstances, and an object of the present invention is to provide a coil component that can obtain a large inductance even if a core made of a metal magnetic body is used.

[0010] Technical solutions for solving technical problems

[0011] In order to achieve the above object, the present invention provides a coil component, comprising:

[0012] A main core having a middle leg portion and an outer leg portion, wherein the middle leg portion is wound with a coil body, and the outer leg portion is connected to the middle leg portion via a base portion; and

[0013] The sub-core is arranged to face the base portion across the middle leg portion.

[0014] A width of a gap between the middle leg portion and the sub-core is larger than a width of a gap between the outer leg portion and the sub-core.

[0015] The inventors of the present invention have conducted intensive research on a coil component that can obtain a higher inductance, and as a result, have found that the inductance can be increased by making the width of the gap between the middle leg and the sub-core larger than the width of the gap between the outer leg and the sub-core, thereby completing the present invention. That is, according to the coil component of the present invention, even if a magnetic core (main core or sub-core) containing a metal magnetic body is used, a higher inductance can be obtained.

[0016] The main core is preferably composed of a magnetic core containing a metal magnetic body (the concept of containing an amorphous alloy magnetic body is adopted). In addition, the sub-core is also preferably composed of a magnetic core containing a metal magnetic body. In a coil component having a magnetic core containing a metal magnetic body like this, the change in characteristics with respect to temperature change is small even in a high temperature environment such as 100 to 170°C.

[0017] The magnetic core containing a metal magnetic body generally has a relative magnetic permeability of 15 to 100, which is lower than that of a ferrite core. However, by adjusting the width of the gap between the middle leg and the sub-core, a desired higher inductance can be obtained. In addition, in a coil component having a magnetic core other than a magnetic core containing a metal magnetic body and having a relative magnetic permeability as low as 15 to 100, a desired larger inductance can be obtained by applying the scheme of the present invention. However, in a magnetic core with a higher relative dielectric constant, the inductance of the entire magnetic core is more likely to be determined by the characteristics of the material itself than by making the width of the gap between the middle leg and the sub-core larger than the width of the gap between the outer leg and the sub-core.

[0018] The width of the gap between the middle leg and the sub-core (center gap) is preferably 15 to 55 μm, more preferably 20 to 50 μm. It has been confirmed that the inductance is improved by setting the center gap to such a predetermined width. The reason is not necessarily clear, but can be inferred as follows.

[0019] That is, when the center gap is too small, the center gap may become larger by placing an adhesive in the gap, and the sub-core may be easily tilted, and the gap (side gap) between the outer leg and the sub-core may become wider. In addition, when the center gap is too large, the inductance of the entire magnetic core composed of the main core and the sub-core is reduced by this fact itself. Therefore, by setting the center gap to a specified width, it is easy to make the side gap close to 0, thereby improving the inductance of the entire magnetic core.

[0020] Preferably, the sub-core is fixed to the main core by an adhesive provided on the top surface of the middle leg portion. That is, there may be adhesive in the central gap. In addition, preferably, there is no adhesive between the outer leg portion and the sub-core.

[0021] The sub-core is fixed to the main core only by an adhesive provided on the top surface of the middle leg, that is, the main core and the sub-core are fixed only by an adhesive of a center gap of a predetermined width, thereby making it difficult for the sub-core to tilt relative to the main core, and the side gap can be made close to 0, making it easy to increase the inductance of the entire magnetic core. In addition, the main core and the sub-core are not fixed at the outer leg, so even if a thermal expansion difference due to temperature change occurs between the main core and the sub-core, thermal stress does not act on the main core or the sub-core, durability is improved, and characteristic changes due to temperature change are also difficult to occur.

[0022] The coil body is preferably formed of a plate-shaped conductor. By forming it like this, the DC resistance also becomes small, and a large-capacity current can flow through it, and it can also be used appropriately as an inductor of a power supply system, for example. In addition, the coil body can also be formed of a wire.

[0023] In the coil component of the present invention, when the coil body is wound around the middle leg portion in a manner of less than 1 turn, the desired higher inductance can be obtained by adjusting the width of the gap between the middle leg portion and the auxiliary core. In addition, by making the coil body less than 1 turn, the DC resistance is also reduced, and a larger allowable current can flow through the coil body.

[0024] A specific example in which the coil body is wound around the middle leg portion in a manner of less than one turn is not particularly limited, but the following structure is given as an example.

[0025] That is, the coil body has:

[0026] A first main body portion extending along a first axis at one side of the middle foot portion;

[0027] A second main body portion extending along the first axis on a side of the mid-leg portion opposite to the side; and

[0028] A third main body portion connects the first main body portion and the second main body portion so as to surround the middle leg portion.

[0029] By configuring the coil body to have the above-described structure, the coil body can be wound around the middle leg portion in less than one turn.

[0030] Preferably, a first terminal portion is provided at one end portion of the first body portion along the first axis.

[0031] A second terminal portion is provided at one end of the second body portion along the first axis.

[0032] A first dummy terminal portion is provided at the other end portion of the first body portion along the first axis, and a second dummy terminal portion is provided at the other end portion of the second body portion along the first axis.

[0033] The first terminal portion and the second terminal portion can be used as input and output terminals of the inductor element, respectively, and when connected to the mounting substrate, can be connected to other electronic components mounted on the substrate. In addition, by also connecting the two dummy terminal portions to the mounting substrate, the mounting strength of the coil component relative to the mounting substrate is improved.

[0034] It is preferred that the coil body is fixed to either the main core or the sub-core. When the coil body is fixed to both the main core and the sub-core, there is a possibility of deformation due to thermal stress caused by temperature changes at high temperatures between the coil body as a conductor and the main core or the sub-core composed of a non-conductor, and there is a possibility of changes in the center gap or the side gap. However, when the coil body is fixed only to either the main core or the sub-core, it is difficult to generate thermal stress caused by temperature changes at high temperatures, and the stability of the characteristics relative to temperature changes becomes higher.

[0035] The width of the middle leg is preferably greater than that of the outer leg. In addition, the width of the middle leg is preferably 1.5 to 2.5 times the width of the outer leg. By setting it in this way, the magnetic flux generated around the coil body has good permeability, and the inductance and other characteristics are improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a schematic perspective view of a coil component according to one embodiment of the present invention.

[0037] Figure 2 is along Figure 1 A cross-sectional view of the coil component taken along line II-II is shown.

[0038] Figure 3 Yes means Figure 1 An exploded perspective view showing the relationship between the main core, sub-core and coil body of the coil component shown.

[0039] Figure 4 : is a graph showing the relationship between the inductance and the center gap of the coil component according to the present embodiment.

[0040] Description of Reference Numerals

[0041] 10...Coil components

[0042] 20... Coil body

[0043] 21a……First main body

[0044] 21b……Second main body

[0045] 21c……The third main body

[0046] 22a: first terminal portion

[0047] 22b... Second terminal portion

[0048] 23a ...... first dummy terminal portion

[0049] 23b...Second dummy terminal portion

[0050] 30... Main core

[0051] 31...base

[0052] 32... bottom surface of base

[0053] 33…Mid-foot

[0054] 34, 36a, 36b... top surface

[0055] 35a...First external foot

[0056] 35b…Second outer foot

[0057] 37a, 37b...side view

[0058] 38a...first concave portion

[0059] 38b...Second recess

[0060] 38c……The third concave part

[0061] 39a......Recessed portion for first terminal

[0062] 39b ... Recess for second terminal

[0063] 40...Secondary core

[0064] 41...Inner surface

[0065] 42...External surface

[0066] 50……adhesive. DETAILED DESCRIPTION

[0067] Hereinafter, the present invention will be described based on the embodiments shown in the drawings.

[0068] Figure 1 to Figure 3 The coil component 10 of one embodiment of the present invention shown is used, for example, as a power supply inductor, etc. In addition, in the accompanying drawings, the X-axis (first axis), the Y-axis (second axis) and the Z-axis (third axis) are perpendicular to each other. The coil component 10 has a coil body 20, a main core 30 and a sub-core 40. The coil body 20 is arranged on the upper part of the main core 30 in the Z-axis direction, and the sub-core 40 is arranged on the upper part thereof.

[0069] like Figure 3As shown, in the present embodiment, the coil body 20 has a first main body portion 21a, a second main body portion 21b and a third main body portion 21c. The coil body 20 can be obtained by stamping a plate-shaped conductor, but the coil body 20 can also be formed by separately forming the first main body portion 21a, the second main body portion 21b, and the third main body portion 21c and connecting them together.

[0070] The first main body 21a and the second main body 21b are separated from each other by a predetermined distance in the Y-axis direction and extend substantially in parallel in the X-axis direction. A first terminal 22a is provided at one end of the first main body 21a along the X-axis, and a second terminal 22b is provided at the end of the second main body 21b on the same side along the X-axis. The first terminal 22a and the second terminal 22b are formed by bending from one end on the same side of the first main body 21a and the second main body 21b toward the lower side of the Z-axis.

[0071] In addition, a first dummy terminal portion 23a is provided at the other end of the first main body portion 21a along the X-axis, and a second dummy terminal portion 23b is provided at the other end of the second main body portion 21b along the X-axis. The first dummy terminal portion 23a and the second dummy terminal portion 23b are formed by bending from the other end of the same side of the first main body portion 21a and the second main body portion 21b toward the lower side of the Z-axis. The lower front ends of the first terminal portion 22a, the second terminal portion 22b, the first dummy terminal portion 23a and the second dummy terminal portion 23b in the Z-axis direction are narrowed into a cone shape.

[0072] In this embodiment, the third body portion 21c is formed integrally with the first body portion 21a and the second body portion 21b along the Y axis to connect the first dummy terminal portion 23a of the first body portion 21a and the second dummy terminal portion 23b of the second body portion 21b. In this embodiment, it is preferred that the first body portion 21a, the second body portion 21b, and the third body portion 21c have the same plate thickness, but they may also be different. In addition, it is preferred that Figure 2 The Y-axis direction width w5 of the first main body portion 21a and the Y-axis direction width w5 of the second main body portion 21b are the same width. It is also preferred that these widths w5 are equal to Figure 3 The third main body portions 21 c shown have the same width in the Z-axis direction.

[0073] There is no particular limitation on the conductor constituting the coil body 20, and for example, copper, copper alloy, silver, gold, etc. can be used. An insulating coating may also be formed on the surface of the coil body 20, except for the front ends of the terminal portions 22a, 22b, 23a, and 23b. With regard to the front ends of the terminal portions 22a, 22b, 23a, and 23b, it is preferred that the conductor portion is exposed to be electrically connected to, for example, a pad pattern of a mounting substrate. In addition to the terminal portions 22a, 22b, 23a, and 23b, the main core 30 or the auxiliary core 40 is in contact, so when the surfaces of these magnetic cores 30 and 40 are conductors, it is preferred to insulate them. In addition, an insulating coating may also be formed on the surfaces of these magnetic cores 30 and 40.

[0074] like Figure 3 As shown, the main core 30 has a substantially rectangular flat plate-shaped base 31. A middle leg portion 33 is formed along the X axis and protrudes upward along the Z axis at the center portion along the Y axis of the base 31. In addition, a first outer leg portion 35a is formed along the X axis and protrudes upward along the Z axis at one end of the base 31 in the Y axis direction. In addition, a second outer leg portion 35b is formed along the X axis and protrudes upward along the Z axis at the other end of the base 31 in the Y axis direction.

[0075] In the upper part of the base 31, the middle leg 33 and a pair of outer legs 35a and 35b located on both sides of the middle leg 33 in the Y-axis direction are parallel to each other along the X-axis. One end of the middle leg 33 in the X-axis direction protrudes from one end of the base 31 along the X-axis, and the other end of the middle leg 33 in the X-axis direction is on the same plane as the other end of the base 31. In addition, Figure 3 In the figure, one end in the X-axis direction is the depth side along the X-axis, and the other end in the X-axis direction is the front side along the X-axis.

[0076] In addition, one end of each of the pair of outer legs 35a and 35b protrudes from the base 31 along the X-axis to the same extent as the middle leg 33. Therefore, at one end of the base 31 in the X-axis direction, a first terminal recess 39a is formed between the outer leg 35a and the middle leg 33, and a second terminal recess 39b is formed between the outer leg 35b and the middle leg 33.

[0077] In addition, the other end of each of the pair of outer legs 35a, 35b protrudes in the X-axis direction from the middle leg 33. Therefore, at the other end of the base 31 in the X-axis direction, a third terminal recess 39c is formed between the outer legs 35a and the outer legs 35b. The bottom surface of each of the pair of outer legs 35a, 35b is formed to protrude downward in the Z-axis relative to the bottom surface 32 of the base 31, but it may also be as shown in FIG. Figure 2 Shown as being formed into the same plane (flattened).

[0078] like Figure 3As shown, in the upper part of the base 31, a first terminal recess 38a extending in the X-axis direction is formed along the Y-axis between the outer leg 35a and the middle leg 33, and a second terminal recess 38b extending in the X-axis direction is formed along the Y-axis between the outer leg 35b and the middle leg 33. The first recess 38a has the same width in the Y-axis direction as the first terminal recess 39a, and connects the first terminal recess 39a and the third recess 38c. The second recess 38b has the same width in the Y-axis direction as the second terminal recess 39b, and connects the second terminal recess 39b and the third recess 38c.

[0079] The first terminal portion 22a of the coil body 20 enters the first terminal recess 39a, and the second terminal portion 22b of the coil body 20 enters the second terminal recess 39b. In addition, the first body portion 21a of the coil body 20 enters the first recess 38a, and the second body portion 21b of the coil body 20 enters the second recess 38b.

[0080] In addition, the first dummy terminal portion 23a, the second dummy terminal portion 23b and the third main body portion 21c integrally enter the third recess 38c. Therefore, the terminal portions 22a, 22b, 23a, 23b of the coil body 20 do not protrude from both ends of the main core 30 in the X-axis direction in the X-axis direction. The same is true for the third main body portion 21c.

[0081] However, the terminal portions 22a, 22b, 23a, 23b and the third main body portion 21c of the coil body 20 may slightly protrude in the X-axis direction from both ends of the main core 30 in the X-axis direction. This is because it is easy to confirm the welding fillet (weld shoulder) that may be attached to the outer surface of the terminal portions 22a, 22b, 23a, 23b of the coil body 20 in the X-axis direction.

[0082] In addition, the first terminal recess 39a, the second terminal recess 39b and the third recess 38c may not be provided in the main core 30. In this case, the terminal portions 22a, 22b, 23a, 23b and the third main body portion 21c of the coil body 20 protrude from both ends of the main core 30 in the X-axis direction by an amount equivalent to or greater than the thickness of the coil body 20 in the X-axis direction.

[0083] The lower front ends of the first terminal portion 22a, the second terminal portion 22b, the first dummy terminal portion 23a and the second dummy terminal portion 23b along the Z axis protrude downward from the bottom surface of the base 32 and the bottom surfaces of the outer legs 35a and 35b. This is because their lower front ends are electrically connected to, for example, a pad pattern of a mounting substrate.

[0084] In this embodiment, the first body portion 21 a , the second body portion 21 b , and the third body portion 21 c of the coil body 20 surround the center leg portion 33 of the main core 30 on three sides and constitute a coil wound with one turn or less.

[0085] like Figure 2 As shown, a sub-core 40 is arranged on the upper part of the main core 30 in the Z-axis direction. The sub-core 40 has an inner surface 41 and an outer surface, and has a rectangular plate shape as a whole. The width of the sub-core 40 in the X-axis direction and the width of the Y-axis direction are preferably equal to the width of the main core 30 in the X-axis direction and the width in the Y-axis direction, but may be slightly different.

[0086] In this embodiment, if Figure 1 As shown, the length of one side of the sub-core 40 in the X-axis direction is substantially the same as the length of the side surface 37a of the first outer leg 35a and the side surface 37b of the second outer leg 35b in the X-axis direction. In addition, the length of one side of the sub-core 40 in the Y-axis direction is substantially the same as the interval between the side surface 37a of the first outer leg 35a and the side surface 37b of the second outer leg 35b.

[0087] The outer surface 42 of the sub-core 40 is a flat surface, and the outer periphery thereof is chamfered. The outer surface 42 is a substantially flat surface, and a vacuum suction head or the like can be detachably attached to the outer surface 42 to transport the coil component 10 .

[0088] The inner surface 41 of the sub-core 40 is also a flat surface, and the sub-core 40 is arranged and fixed on the upper part of the main core 30 in the Z-axis direction in such a manner that the top surface 34 of the middle leg 33 and the top surfaces 36a and 36b of the outer legs 35a and 35b face the inner surface 41. In this embodiment, the adhesive 50 is only between the top surface 34 of the middle leg 33 and the inner surface 41 of the sub-core 40, and there is no adhesive 50 between the top surfaces 36a and 36b of the outer legs 35a and 35b and the inner surface of the sub-core 40. That is, in this embodiment, the main core 30 and the sub-core 40 are fixed only by the adhesive 50 of the middle leg 33.

[0089] like Figure 2 As shown, the width w3 of the middle leg portion 33 along the Y axis is larger than the width w4 of the outer legs 35a and 35b, and is preferably designed to be 1.5 to 2.5 times. In addition, the width w4 of the first outer leg portion 35a and the width w4 of the second outer leg portion 35b do not have to be the same length, but are preferably substantially the same. In addition, the widths w5 of the first recess 38a and the second recess 38b along the Y axis are determined to allow the first body portion 21a and the second body portion 21b to enter the recesses 38a and 38b, respectively, and are slightly larger than their widths along the Y axis.

[0090] The width w5 of each of the first recess 38a and the second recess 38b along the Y axis is preferably determined to be equal to or greater than the width w4 of each of the outer legs 35a and 35b and smaller than the width w3 of the middle leg 33. The width w3 of the middle leg 33 is about 1 / 6 to 1 / 2 of the full width w0 of the main core 30 along the Y axis.

[0091] In the present embodiment, the height h1 from the bottom surface of each recess 38a, 38b to the top surface 34 of the middle leg portion 33 is lower than the height h2 from the bottom surface of each recess 38a, 38b to the top surface of each outer leg portion 35a, 35b. The difference (h2-h1) between the height h2 and the height h1 is preferably 15 to 55 μm, and more preferably 20 to 50 μm.

[0092] In addition, in the present embodiment, when the gap between the top surface 34 of the middle leg portion 33 and the inner surface 41 of the sub-core 40, i.e., the center gap is set as w1, and the gap between each top surface 36a, 36b of the outer leg portions 35a, 35b and the inner surface 41 of the sub-core 40 is set as the side gap w2, it is preferred that the center gap w1 is larger than the side gap w2. Furthermore, it is preferred that each top surface 36a, 36b of the outer leg portions 35a, 35b is in contact with the inner surface 41 of the sub-core 40, and it is preferred that the side gap w2 is substantially 0. In addition, it is preferred that the thickness of the adhesive 50 is the same as the center gap w1.

[0093] The thickness of the main body 21a, 21b accommodated in each recess 38a and 38b along the Z axis is preferably the same as the height h1 of the middle leg 33, but it can also be smaller or larger than it. The greater the thickness of the main body 21a, 21b along the Z axis, the more the DC resistance of the coil body 20 can be reduced. In the present embodiment, the thickness of the main body 21a, 21b along the Z axis is preferably smaller than the height h2 of the outer leg 35a, 35b. However, by making the inner surface 41 of the sub-core 40 not a flat surface, and forming recesses on the inner surface 41 at positions corresponding to each recess 38a, 38b, the thickness of the main body 21a, 21b along the Z axis can also be made larger than the height h2 of the outer leg 35a, 35b.

[0094] In this embodiment, the first main body 21a is fixed to the bottom surface of the first recess 38a by an adhesive, and similarly, the second main body 21b is fixed to the bottom surface of the second recess 38b by an adhesive. In addition, the main bodies 21a and 21b are not fixed to the inner surface 41 of the sub-core 40 by bonding or the like. In other embodiments, the first main body 21a may not be fixed to the bottom surface of the first recess 38a by an adhesive, and similarly, the second main body 21b may not be fixed to the bottom surface of the second recess 38b by an adhesive. Alternatively, the main bodies 21a and 21b may be fixed to the inner surface 41 of the sub-core 40 by an adhesive or the like.

[0095] In the present embodiment, the main core 30 is formed of a composite magnetic body including a metal magnetic body (including an amorphous alloy magnetic body) and a resin. Alternatively, the main core 30 may be a sintered body of a metal magnetic body. In addition, the sub-core 40 is also formed of a composite magnetic body including a metal magnetic body and a resin. Alternatively, the sub-core 40 may be a sintered body of a metal magnetic body. The relative magnetic permeability of the main core 30 and the sub-core 40 is, for example, in the range of 15 to 100. As the metal magnetic body, for example, a Co-based amorphous alloy or the like can be used.

[0096] Furthermore, the main core 30 and the sub-core 40 may be formed of different types of magnetic materials, or the sub-core 40 may be formed of a non-magnetic material such as resin or ceramics.

[0097] According to the coil component 10 of this embodiment, the inventors have confirmed that a larger inductance can be obtained even if the main core 30 and the sub-core 40 made of a metal magnetic body are used. In addition, in this embodiment, the magnetic cores 30 and 40 made of a metal magnetic body are provided, so that even in a high temperature environment of 100 to 170°C, the change in characteristics with respect to temperature change is small.

[0098] In addition, the magnetic cores 30 and 40 made of metal magnetic body generally have a relative magnetic permeability of 15 to 100, which is lower than the relative magnetic permeability of ferrite cores. However, a desired large inductance can be obtained by adjusting the width w1 of the gap between the middle leg portion 33 and the sub-core 40. In addition, in a coil component having a magnetic core other than a magnetic core made of metal magnetic body and having a relative magnetic permeability as low as 15 to 100, a desired large inductance can also be obtained by applying the scheme of this embodiment.

[0099] In this embodiment, the center gap w1 between the middle leg portion 33 and the sub-core 40 is 15 to 55 μm, more preferably 20 to 50 μm. It is confirmed that the inductance is improved by setting the center gap w1 to such a predetermined width. The reason is not necessarily clear, but it can be inferred as follows.

[0100] That is, in Figure 2 In the structure shown, when the center gap w1 is too small, the center gap w1 may become larger due to the thickness of the adhesive 50 by providing the adhesive 50 in the gap. Figure 2 The reason is that due to the left and right inclination of the outer leg 35a or 35b and the inner surface 41 of the sub-core 40, the gap (side gap) between them may become wider. In addition, when the center gap w1 is too large, the inductance of the entire magnetic core composed of the main core 30 and the sub-core 40 is reduced by this fact. Therefore, by setting the center gap w1 to a predetermined width, it is easy to make the side gap close to 0, thereby improving the inductance of the entire magnetic core.

[0101] In the present embodiment, the sub-core 40 is fixed to the main core 30 by an adhesive 50 provided on the top surface 34 of the middle leg portion 33. In addition, there is no adhesive between the outer leg portions 35a, 35b and the sub-core 40.

[0102] The sub-core 40 is fixed to the main core 30 only by the adhesive 50 provided on the top surface 34 of the middle leg portion 33, thereby making it difficult for the sub-core 40 to tilt relative to the main core 30, and the side gap w2 on both sides can be made close to 0, which makes it easy to increase the inductance of the entire magnetic core. In addition, the main core 30 and the sub-core 40 are not fixed at the outer legs 35a and 35b, so even if a thermal expansion difference caused by temperature change occurs between the main core 30 and the sub-core 40, it is difficult to apply thermal stress to the main core 30 or the sub-core 40, and the durability is improved, and it is also difficult to cause characteristic changes caused by temperature change.

[0103] In addition, in the present embodiment, the coil body 20 is formed of a plate-shaped conductor. By configuring in this way, the DC resistance is also reduced, a large amount of current can be passed, and it can be suitably used as an inductor of a power supply system, for example.

[0104] In addition, in the coil component 10 of the present embodiment, even when the coil body 20 is wound around the middle leg portion 33 in a manner less than 1 turn, a desired higher inductance can be obtained by adjusting the width w1 of the gap between the middle leg portion 33 and the sub-core 40. In addition, by making the coil body 20 less than 1 turn, the DC resistance is also reduced, and a larger allowable current can flow through the coil body 20.

[0105] In addition, in this embodiment, Figure 3 The first terminal portion 22a and the second terminal portion 22b shown can be used as input and output terminals of the inductor element, respectively, and when connected to the mounting substrate omitted from the figure, can be connected to other electronic components mounted on the substrate. In addition, by also connecting the two dummy terminal portions 23a, 23b to the mounting substrate, the mounting strength of the coil component 10 relative to the mounting substrate is improved.

[0106] Moreover, in the present embodiment, the coil body 20 is fixed only to either the main core 30 or the sub-core 40. When the coil body 20 is fixed to both the main core 30 and the sub-core 40, there is a possibility of deformation due to thermal stress caused by temperature changes at high temperatures between the coil body 20 as a conductor and the main core 30 or the sub-core 40 composed of non-conductors, and there is a possibility of changes in the center gap or the side gap. However, when the coil body 20 is fixed only to either the main core 30 or the sub-core 40, the influence of stress caused by thermal expansion differences caused by temperature changes at high temperatures becomes smaller, and the stability of the characteristics relative to temperature changes becomes higher.

[0107] In addition, in the present embodiment, the width w3 of the middle leg 33 is larger than the width w4 of the outer legs 35a and 35b, and the width w3 of the middle leg 33 is preferably 1.5 to 2.5 times the width w4 of the outer legs 35a and 35b. By setting it in this way, the magnetic flux lines generated around the coil body 20 have good permeability, and the characteristics such as inductance are improved.

[0108] In addition, the present invention is not limited to the above-mentioned embodiment, and various changes can be made within the scope of the present invention.

[0109] In the above-mentioned embodiment, the X-axis, Y-axis, and Z-axis are described as mutually perpendicular axes, but the angle between these axes only needs to be approximately 90 degrees, and may include angles in a range that produce the same effect even if they are not 90 degrees.

[0110] In the above embodiment, the third body portion 21c is connected to the first body portion 21a and the second body portion 21b via the first and second dummy terminals 23a and 23b, but the third body portion 21c may be directly connected to the first and second body portions 21a and 21b.

[0111] In addition, in the above-described embodiment, the top surface 34 , the top surface 36 a , and the top surface 36 b are flat surfaces, but these top surfaces may all be curved surfaces, or may all be stepped surfaces.

[0112] In the above-mentioned embodiment, a so-called I core is used as the sub-core 40, but a so-called C core having an outer leg portion may be used, and the outer leg portion of the sub-core 40 is arranged to face the outer leg portions 35a and 35b of the main core 30. Alternatively, a so-called E core having a middle leg portion 33 and outer leg portions 35a and 35b like the main core 30 may be used as the sub-core 40. That is, the middle leg portion and the outer leg portion of the sub-core may be arranged to face the middle leg portion and the outer leg portion of the main core.

[0113] Alternatively, the main core 30 and the sub-core 40 may be combined at both the top surface 36 a and the top surface 36 b to form a single magnetic core. In this case, the coil component 10 can be manufactured without the adhesive 50 .

[0114] In the above-described embodiment, the main core 30 is made of a metal magnetic body with little temperature change in order to be used in a high temperature environment (100 to 170° C.), but the present invention is not limited thereto and a ferrite core may also be used.

[0115] In addition, as another embodiment, two or more middle legs of the main core 30 may be arranged in parallel in the Y-axis direction. In this case, a recess is formed between each middle leg. In this embodiment, the coil body may be formed by a plate-shaped conductor having a terminal portion for conducting electricity at the end.

[0116] In addition, the coil body 20 is not limited to a plate-shaped conductor, and may be a conductive wire.

[0117] Example

[0118] Hereinafter, the present invention will be described based on more detailed examples, but the present invention is not limited to these examples.

[0119] Example 1

[0120] Made Figures 1 to 3 The sample of the coil component 10 shown in FIG.

[0121] The center gap w1 of the coil component 10 of this embodiment is as follows: Figure 4 The inductance L of each sample of the coil component 10 was measured using an impedance analyzer. The results are shown in Figure 4 Indicated in.

[0122] If the Figure 4 As shown in the figure, it is determined that when the center gap w1 is slightly increased from 0, the inductance decreases, but it turns to increase at about 10μm. Moreover, it is determined that after w1 is 15μm to 20μm, a larger inductance is obtained than when w1 is 0. In addition, it is determined that the inductance obtained as w1 increases also increases, and when w1 exceeds 55μm, the inductance obtained becomes lower than when w1 is 0.

Claims

1. A coil component, characterized in that: include: A main core having a middle leg portion and an outer leg portion, wherein the middle leg portion is wound with a coil body, and the outer leg portion is connected to the middle leg portion via a base portion; as well as a sub-core arranged to face the base portion across the middle leg portion, The coil body is formed of a plate-shaped conductor. The coil body is wound around the middle leg portion in a manner of less than one turn. The height from the bottom surface of the recessed portion formed in the main core and accommodating the coil body to the top surface of the middle leg portion is lower than the height from the bottom surface of the recessed portion to the top surface of the outer leg portion. The width of the gap between the middle leg and the sub-core is greater than the width of the gap between the outer leg and the sub-core. The relative magnetic permeability of the main core is 15 to 100. The width of the gap between the middle leg and the sub-core is 15 to 55 μm. The sub-core is fixed to the main core by an adhesive provided on the top surface of the mid-leg portion, and there is no adhesive between the outer leg portion and the sub-core.

2. The coil component according to claim 1, wherein: The main core includes a metallic magnetic body.

3. The coil component according to claim 1 or 2, characterized in that: The relative magnetic permeability of the sub-core is 15-100.

4. The coil component according to claim 1 or 2, characterized in that: The sub-core is fixed to the main core by an adhesive disposed on the top surface of the mid-leg portion.

5. The coil component according to claim 1 or 2, characterized in that: The coil body has: a first main body portion extending along a first axis on one side of the midfoot portion; a second body portion extending along the first axis on a side of the midfoot portion opposite to the one side; and A third main body portion connects the first main body portion and the second main body portion so as to surround the middle leg portion.

6. The coil component according to claim 5, characterized in that: A first terminal portion is provided at one end of the first body portion along the first axis, A second terminal portion is provided at one end of the second body portion along the first axis, A first dummy terminal portion is provided at the other end portion of the first body portion along the first axis, and a second dummy terminal portion is provided at the other end portion of the second body portion along the first axis.

7. The coil component according to claim 1 or 2, characterized in that: The coil body is fixed to either the main core or the sub-core.

8. The coil component according to claim 1 or 2, characterized in that: The width of the middle foot portion is greater than the width of the outer foot portion.

9. The coil component according to claim 8, characterized in that: The width of the middle leg portion is 1.5 to 2.5 times the width of the outer leg portion.

Images