Coil Device

Abstract

To provide a coil device that can prevent the occurrence of AC loss and has better inductance characteristics.SOLUTION: A coil device 10 includes a first core 20a having first outer legs 22a and 22a, a second core 20b that is arranged while forming gaps G1 and G2 between the first outer legs 22a and 22a, and a conductor 30 that is at least partially located between the first core 20a and the second core 20b, and the conductor 30 is formed with outer notches 36 and 37 at positions corresponding to the gaps G1 and G2.SELECTED DRAWING: Figure 1B

Description

[Technical Field]

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

[0002] A coil device used as an inductor or the like is known, for example, from the coil device described in Patent Document 1. The coil device described in Patent Document 1 has a first core member, a core body disposed across a gap from the first core member, and a conductor attached to the core body so as to face the gap. In the coil device described in Patent Document 1, the shape of the core body is changed at the attachment position of the conductor, thereby positioning the conductor at a position away from the gap. This makes it difficult for leakage magnetic flux generated in the gap to impinge on the surface of the conductor, making it difficult for eddy currents to be generated on the surface of the conductor, and making it possible to prevent AC loss due to eddy currents.

[0003] However, in the coil device described in Patent Document 1, changing the shape of the core body reduces the volume of the core body, which may result in a deterioration in inductance characteristics. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-129253 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a coil device that can prevent the occurrence of AC loss and has good inductance characteristics. [Means for solving the problem]

[0006] In order to achieve the above object, a coil device according to the present invention comprises: a first core portion having a first leg portion; a second core portion disposed to form a gap between itself and the first leg portion; a conductor at least a portion of which is disposed between the first core portion and the second core portion, The conductor has a notch formed at a position corresponding to the gap.

[0007] In the coil device according to the present invention, a notch is formed in the conductor at a position corresponding to the gap. Therefore, at the position corresponding to the gap, the surface of the conductor is positioned at a distance corresponding to the depth of the notch from the gap, making it difficult for leakage magnetic flux generated in the gap to impinge on the surface of the conductor. Therefore, eddy currents are unlikely to be generated on the surface of the conductor, and AC loss due to eddy currents can be prevented.

[0008] Furthermore, in the coil device according to the present invention, the conductor has a notch formed at a position corresponding to the gap, so unlike the prior art, there is no need to change the shape of the first or second core part to prevent leakage magnetic flux generated in the gap from hitting the surface of the conductor. This makes it possible to ensure a sufficient volume for the first or second core part, and to realize a coil device with good inductance characteristics.

[0009] Preferably, the notch is formed in the conductor along an edge of the first leg adjacent to the conductor. With this configuration, leakage magnetic flux generated in the gap is less likely to hit the surface of the conductor at each portion of the gap extending along the edge of the first leg, thereby effectively preventing eddy currents from being generated on the surface of the conductor.

[0010] Preferably, the depth of the notch is greater than the width of the gap. With this configuration, the surface of the conductor can be positioned sufficiently away from the gap at the position corresponding to the gap. Therefore, leakage magnetic flux generated in the gap is less likely to hit the surface of the conductor, effectively preventing eddy currents from being generated on the surface of the conductor.

[0011] The second core portion may have a second leg portion disposed opposite the first leg portion, and the notch portion may be formed in the conductor at a position corresponding to the gap formed between the first leg portion and the second leg portion. By adopting such a configuration, it is possible to obtain the various effects described above in a coil device having a core such as a so-called EE type or UU type.

[0012] Preferably, the notch is a recessed groove. With this configuration, when a gap is formed between the first leg and the second leg, the notch can be positioned opposite the gap. This makes it difficult for leakage flux generated in the gap to impinge on the surface of the conductor, effectively preventing eddy currents from being generated on the surface of the conductor.

[0013] The second core portion may have a flat plate shape, and the notch may be formed in the conductor at a position corresponding to the gap formed between the first leg portion and the second core portion. By adopting such a configuration, it is possible to obtain the various effects described above in a coil device having a core such as a so-called EI type.

[0014] Preferably, the cutouts are formed by chamfering the sides of the conductor. With this configuration, when a gap is formed between the first leg and the flat second core, the cutouts can be positioned at a position corresponding to the gap. This makes it difficult for leakage flux generated in the gap to impinge on the surface of the conductor, effectively preventing eddy currents from occurring on the surface of the conductor.

[0015] The first leg may have a pair of outer legs and a center leg disposed between each of the pair of outer legs, and the notch may be formed in the conductor at a position corresponding to a gap formed between the second core and at least one of the outer legs and the center leg. By adopting such a configuration, it is possible to obtain the various effects described above in a coil device having a core such as a so-called EE type or EI type.

[0016] The conductor may have a curved shape, and the notch may be formed on at least one of the inner and outer peripheral sides of the conductor. For example, if the first leg has an outer leg and a center leg, forming the notch on the outer peripheral side of the conductor makes it difficult for leakage magnetic flux generated in the gap formed between the outer leg and the second core to hit the outer peripheral side of the conductor, thereby effectively preventing eddy currents from being generated on the surface of the conductor. Also, forming the notch on the inner peripheral side of the conductor makes it difficult for leakage magnetic flux generated in the gap formed between the center leg and the second core to hit the inner peripheral side of the conductor, thereby effectively preventing eddy currents from being generated on the surface of the conductor.

[0017] Preferably, the conductor has a mounting portion connected to an external circuit, and a part of the notch is formed in the mounting portion. With this configuration, leakage magnetic flux generated in the gap is less likely to hit the surface of the mounting portion, and eddy currents can be effectively prevented from being generated on the surface of the conductor. [Brief explanation of the drawings]

[0018] [Figure 1A] FIG. 1A is a perspective view of a coil device according to a first embodiment of the present invention. [Figure 1B] FIG. 1B is a plan view of the coil device shown in FIG. 1A. [Figure 1C] FIG. 1C is a bottom view of the coil device shown in FIG. 1A. [Figure 2] FIG. 2 is an exploded perspective view of the coil device shown in FIG. 1A. [Figure 3A] FIG. 3A is a perspective view of the coil shown in FIG. [Figure 3B] FIG. 3B is a perspective view of the coil shown in FIG. 3A when viewed from a different angle. [Figure 4A] FIG. 4A shows the change in wire loss (copper loss) when the gap width is changed. [Figure 4B] FIG. 4B is a diagram showing the change in wire loss (copper loss) when the frequency of the AC current flowing through the conductor is changed. [Figure 4C] FIG. 4C is a diagram showing the change in wire loss (copper loss) when the relative permeability of the material constituting the core is changed. [Figure 4D] FIG. 4D is a diagram showing the change in wire loss (copper loss) when the current value (peak-to-peak value) of the AC current flowing through the conductor is changed. [Figure 4E] FIG. 4E is a diagram showing the distribution of wire loss (copper loss) in a conductor. [Figure 4F] FIG. 4F is a diagram showing the magnetic flux distribution in the core. [Figure 5A] FIG. 5A is a perspective view of a coil device according to a second embodiment of the present invention. [Figure 5B] FIG. 5B is a side view of the coil device shown in FIG. 5A. [Figure 6] FIG. 6 is an exploded perspective view of the coil device shown in FIG. 5A. [Figure 7A] FIG. 7A is a perspective view of a coil device according to a third embodiment of the present invention. [Figure 7B] FIG. 7B is a side view of the coil device shown in FIG. 7A. [Figure 8] FIG. 8 is an exploded perspective view of the coil device shown in FIG. 7A. [Figure 9] FIG. 9 is a perspective view showing a modified example of the coil shown in FIG. [Figure 10] FIG. 10 is an exploded perspective view of a coil device according to a fourth embodiment of the present invention. [Figure 11] FIG. 11 is a side view of the coil device shown in FIG. 10 with one core removed. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, the present invention will be described based on the embodiments shown in the drawings.

[0020] First embodiment 1A, coil device 10 is, for example, an inductor, and has first core 20a, second core 20b, and conductor 30. The width of coil device 10 in the X-axis direction is preferably 3.0 to 20.0 mm, the width of coil device 10 in the Y-axis direction is preferably 3.0 to 20.0 mm, and the width of coil device 10 in the Z-axis direction is preferably 3.0 to 20.0 mm.

[0021] As shown in Fig. 2, the first core 20a and the second core 20b have the same shape, a so-called E-shape. The first core 20a and the second core 20b are arranged to face each other in the Y-axis direction and are joined together using an adhesive or the like. The first core 20a and the second core 20b are made of a magnetic material, and are produced by molding and sintering magnetic powder made of a magnetic material with relatively high magnetic permeability, such as Ni-Zn ferrite, Mn-Zn ferrite, or a metallic magnetic material.

[0022] The first core 20a has a first base portion 21a, a first groove portion 24a, first side groove portions 25a, 25a, and a first leg portion. In this embodiment, the first core 20a is provided with a pair of first outer legs 22a, 22a, and a first center leg portion 23a disposed between each of the pair of first outer legs 22a, 22a, as the first leg portion. The first base portion 21a has a substantially flat plate shape (a substantially rectangular parallelepiped shape).

[0023] The pair of first outer legs 22a, 22 are formed at one end and the other end of the first base portion 21a in the X-axis direction, with a predetermined distance between them. Each of the first outer legs 22a, 22a protrudes a predetermined length from one surface of the first base portion 21a in the Y-axis direction toward one side in the Y-axis direction. Each of the first outer legs 22a, 22a has an elongated shape in the Z-axis direction and extends from the upper end to the lower end of the first base portion 21a in the Z-axis direction.

[0024] The first center leg 23a is formed at approximately the center in the X-axis direction of the first base portion 21a. The first center leg 23a protrudes a predetermined length from one surface of the first base portion 21a in the Y-axis direction toward one side in the Y-axis direction. The first center leg 23a has an elongated shape in the Z-axis direction and extends from the upper portion of the first base portion 21a in the Z-axis direction (a position approximately equal to the thickness of the conductor 30 below the upper end) to the lower end. The protruding width of the first center leg 23a in the Y-axis direction is approximately equal to the protruding width of the first outer leg 22a in the Y-axis direction. In the illustrated example, the width of the first center leg 23a in the X-axis direction is greater than the width of the first outer leg 22a in the X-axis direction, approximately twice as large.

[0025] The first groove 24a has a shape (substantially U-shaped) corresponding to the shape of the conductor 30, and extends along the periphery of the first center leg 23a. The conductor 30 can be disposed in the first groove 24a. The first groove 24a has a first side portion 241, a second side portion 242, and an upper portion 243.

[0026] The first side portion 241 and the second side portion 242 each extend substantially linearly along the Z-axis direction, extending from the upper end to the lower end of the first base portion 21a in the Z-axis direction. The first side portion 241 is formed between the first outer leg portion 22a and the first center leg portion 23a located on one side in the X-axis direction, and the second side portion 242 is formed between the first outer leg portion 22a and the first center leg portion 23a located on the other side in the X-axis direction. The width in the X-axis direction of each of the first side portion 241 and the second side portion 242 is approximately the same as or greater than the thickness (plate thickness) of the conductor 30. As will be described later, the first conductor side portion 31 of the conductor 30 is disposed on the first side portion 241, and the second conductor side portion 32 of the conductor 30 is disposed on the second side portion 242.

[0027] The upper portion 243 is formed above the first base portion 21a and extends along the X-axis direction. The upper portion 243 connects the upper end of the first side portion 241 and the upper end of the second side portion 242. The width of the upper portion 243 in the Z-axis direction is approximately the same as or greater than the thickness (plate thickness) of the conductor 30. As will be described later, the conductor upper portion 33 of the conductor 30 is disposed in the upper portion 243.

[0028] The pair of first side grooves 25a, 25a are formed below the first outer leg portions 22a, 22a located on one side and the other side in the X-axis direction, respectively, and extend along the X-axis direction toward one end side and the other end side of the first base portion 21a in the X-axis direction. The first side grooves 25a, 25a are connected to the lower ends of the side portions 241, 242, respectively, and the side portions 241, 242 and the first side grooves 25a, 25a form a substantially L-shaped groove. The width of each of the first side grooves 25a, 25a in the Z-axis direction is approximately the same as or greater than the thickness (plate thickness) of the conductor 30. As described below, the mounting portions 34, 35 of the conductor 30 are disposed in the first side grooves 25a, 25a, respectively.

[0029] When the conductor 30 is placed inside the first groove portion 24a, the first center leg portion 23a is placed inside the conductor 30, and the first outer legs 22a, 22a are placed outside the conductor 30.

[0030] The second core 20b has a second base portion 21b, a second groove portion 24b, second side groove portions 25b, and a second leg portion. In this embodiment, the second core 20b is provided with a pair of second outer legs 22b and a second center leg portion 23b (FIGS. 1B and 1C) disposed between each of the pair of second outer legs 22b. The second legs (the second outer legs 22b and the second center leg 23b) are disposed opposite the first legs (the first outer legs 22a and the first center leg 23a). Because the shape of the second core 20b is similar to that of the first core 20a, a description of the shapes of the above-described portions of the second core 20b will be omitted.

[0031] 1B, the first core 20a and the second core 20b can be combined by joining, with an adhesive or the like (not shown), one surface of the first core 20a located on the opposite side of the Y axis from the first base portion 21a to one surface of the second core 20b located on the opposite side of the Y axis from the second base portion 21b. More specifically, the outer legs 22a, 22b of the cores 20a, 20b are joined together and / or the center legs 23a, 23b are joined together.

[0032] When the first core 20a and the second core 20b are combined while facing each other in the Y-axis direction, gaps G1 and G2 having a predetermined width in the Y-axis direction are formed between the first core 20a and the second core 20b at the positions where the outer legs 22a and 22b are formed, and a gap G3 having a predetermined width in the Y-axis direction is formed at the position where the middle legs 23a and 23b are formed.

[0033] Gap G1 has a predetermined length in the X-axis direction and is formed between the first outer leg 22a and the second outer leg 22b located on one side in the X-axis direction. Gap G2 has a predetermined length in the X-axis direction and is formed between the first outer leg 22a and the second outer leg 22b located on the other side in the X-axis direction. The lengths of gaps G1 and G2 in the X-axis direction are equal to the lengths of outer legs 22a and 22b in the X-axis direction. Gaps G1 and G2 also have a predetermined length in the Z-axis direction, which is equal to the lengths of outer legs 22a and 22b in the Z-axis direction.

[0034] Gap G3 has a predetermined length in the X-axis direction and is formed between first center leg 23a and second center leg 23b. The length of gap G3 in the X-axis direction is equal to the lengths of center legs 23a and 23b in the X-axis direction. In the illustrated example, the length of gap G3 in the X-axis direction is longer than the lengths of gaps G1 and G2 in the X-axis direction. Gap G3 also has a predetermined length in the Z-axis direction, which is equal to the lengths of first center legs 23a and 23b in the Z-axis direction. Gaps G1 to G3 are formed on the same straight line along the boundary between first core 20a and second core 20b.

[0035] The width W1 of gap G1 in the Y-axis direction is preferably 0.1 to 1.0 mm, and more preferably 0.1 to 0.5 mm. The same applies to the widths of gaps G2 and G3 in the Y-axis direction. Note that the widths of gaps G1 to G3 in the Y-axis direction may be different from each other.

[0036] As shown in FIG. 2, the conductor 30 is made of a conductive plate and has a curved shape (approximately U-shaped). The conductor 30 is disposed between the first core 20a and the second core 20b. The material constituting the conductor 30 is, for example, a good conductor such as copper, copper alloy, silver, or nickel, but is not particularly limited as long as it is a conductive material. The conductor 30 is formed, for example, by machining a metal plate, but the method for forming the conductor 30 is not limited thereto. In the illustrated example, the conductor 30 has a vertically elongated shape, and the height of the conductor 30 in the Z-axis direction is longer than its length in the X-axis direction.

[0037] The conductor 30 has a first conductor side portion 31, a second conductor side portion 32, a conductor upper portion 33, a first mounting portion 34, and a second mounting portion 35. The first conductor side portion 31 and the second conductor side portion 32 each extend along the Z-axis direction. The side of the conductor 30 where the first conductor side portion 31 is located functions as an input terminal (or an output terminal), and the side where the second conductor side portion 32 is located functions as an output terminal (or an input terminal). The conductor upper portion 33 extends along the X-axis direction and connects the first conductor side portion 31 and the second conductor side portion 32 to each other.

[0038] The first mounting portion 34 and the second mounting portion 35 are formed continuously with (integrally with) one end and the other end of the conductor 30, i.e., the lower ends of the first conductor side portion 31 and the second conductor side portion 32, respectively. The conductor 30 can be connected to an external circuit (not shown) of the mounting board via these mounting portions 34, 35. The mounting portions 34, 35 are bent in a direction approximately perpendicular to the conductor side portions 31, 32 and extend outward in the X-axis direction. The conductor 30 is joined to the external circuit (not shown) via a connecting member such as solder or a conductive adhesive.

[0039] 1A and 1C, the ends of the mounting portions 34, 35 are exposed to the outside from the sides of the first core 20a and the second core 20b in the X-axis direction. Similarly, as shown in Fig. 1C, the bottom surfaces of the mounting portions 34, 35 are exposed to the outside from below the first core 20a and the second core 20b. By exposing the mounting portions 34, 35 to the outside in this manner, heat generated around the mounting portions 34, 35 can be efficiently dissipated to the outside of the cores 20a, 20b.

[0040] 2 and 3A, in this embodiment, cutouts are formed in the conductor 30. More specifically, a first outer cutout 36 and a second outer cutout 37 are formed on the outer circumferential side (front surface) of the conductor 30, and an inner cutout 38 is formed on the inner circumferential side (back surface) of the conductor 30.

[0041] The first outer cutout 36 is formed on the surfaces of the first conductor side portion 31 and the first mounting portion 34, and extends along the extension direction (longitudinal direction) of the first conductor side portion 31 and the first mounting portion 34. The first outer cutout 36 is a recessed groove with a tapered surface formed on the inside. The shape of the first outer cutout 36 is substantially L-shaped, which is the same as the shape of the first conductor side portion 31 and the first mounting portion 34. The first outer cutout 36 is formed in approximately the center of the first conductor side portion 31 and the first mounting portion 34 in the Y-axis direction, and extends continuously from the upper end of the first conductor side portion 31 to the end of the first mounting portion 34.

[0042] The second outer cutout 37 is formed on the surfaces of the second conductor side 32 and the second mounting portion 35, and extends along the extension direction (longitudinal direction) of the second conductor side 32 and the second mounting portion 35. The second outer cutout 37 is a recessed groove with a tapered surface formed on the inside. The shape of the second outer cutout 37 is substantially L-shaped, which is the same as the shape of the second conductor side 32 and the second mounting portion 35. The second outer cutout 37 is formed in approximately the center of the second conductor side 32 and the second mounting portion 35 in the Y-axis direction, and extends continuously from the upper end of the second conductor side 32 to the end of the second mounting portion 35.

[0043] The outer cutouts 36, 37 are formed so that their width in the Y-axis direction narrows toward the depth direction. Note that the shape of the outer cutouts 36, 37 is not limited to this, and may be modified as appropriate, for example, by omitting the tapered surface.

[0044] 1B and 2, the outer cutouts 36, 37 are formed in the conductor 30 at positions corresponding to the gaps G1, G2 (positions close to the gaps G1, G2). More specifically, the outer cutouts 36, 37 are formed in the conductor side portions 31, 32 so as to extend in the Z-axis direction along the outer leg edges 22a1, 22b1 of the outer legs 22a, 22b adjacent to the conductor 30. The outer cutouts 36, 37 are also formed in the mounting portions 34, 35 so as to extend in the X-axis direction along the lower ends of the outer legs 22a, 22b.

[0045] The first outer cutout 36 faces (is facing) the other end of gap G1 in the X-axis direction, and at a position corresponding to gap G1, the distance between the surface of conductor 30 and the other end of gap G1 in the X-axis direction is a distance corresponding to the depth D of first outer cutout 36. The second outer cutout 37 faces (is facing) one end of gap G2 in the X-axis direction, and at a position corresponding to gap G2, the distance between the surface of conductor 30 and one end of gap G2 in the X-axis direction is a distance corresponding to the depth of second outer cutout 37.

[0046] The width in the Y-axis direction of the outer cutouts 36, 37 is greater than the width in the Y-axis direction of the gaps G1, G2. The ratio W2 / W1 of the width W2 in the Y-axis direction of the first outer cutout 36 to the width W1 in the Y-axis direction of the gap G1 is preferably 0.5 to 10, more preferably 1 to 7, and particularly preferably 3 to 5. The same applies to the ratio of the width in the Y-axis direction of the second outer cutout 37 to the width in the Y-axis direction of the gap G2.

[0047] The ratio W2 / W3 of the width W2 of the first outer cutout 36 in the Y-axis direction to the width W3 of the conductor 30 in the Y-axis direction is preferably 0.2 to 0.8, and more preferably 0.3 to 0.5. The same applies to the ratio of the width W2 of the second outer cutout 37 in the Y-axis direction to the width W3 of the conductor 30 in the Y-axis direction.

[0048] The ratio D / T1 of the depth D of the first outer cutout 36 to the thickness T1 of the conductor 30 is preferably 0.1 to 0.5, and more preferably 0.2 to 0.4. The same applies to the ratio of the depth D of the second outer cutout 37 to the thickness T1 of the conductor 30.

[0049] The relationship between the depth D of the first outer cutout 36 and the width W1 of the gap G1 in the Y-axis direction is preferably D>W1, but is not limited to this. The ratio D / W1 of the depth D to the width W1 is preferably 0.5 to 5, and more preferably 1 to 3. The same applies to the relationship between the depth of the second outer cutout 37 and the width W1 of the gap G2 in the Y-axis direction.

[0050] In this embodiment, by determining the values ​​of W2 / W1, W2 / W3, D / T1 or D / W1 as described above, or by making D>W1, it is possible to prevent leakage magnetic flux generated in gaps G1 and G2 from hitting conductor side portions 31 and 32 and mounting portions 34 and 35 at positions corresponding to gaps G1 and G2.

[0051] As shown in FIGS. 2, 3A, and 3B, the inner cutout 38 is formed on the back surface of the first conductor side portion 31, the second conductor side portion 32, and the conductor upper portion 33, and extends along the extension direction (longitudinal direction) of the first conductor side portion 31, the second conductor side portion 32, and the conductor upper portion 33. The inner cutout 38 is a recessed groove with a tapered surface formed on the inside. The shape of the inner cutout 38 is substantially U-shaped, which is the same as the shape of the first conductor side portion 31, the second conductor side portion 32, and the conductor upper portion 33. The inner cutout 38 is formed in the approximate center in the Y-axis direction of the first conductor side portion 31, the second conductor side portion 32, and the conductor upper portion 33, and extends continuously from the lower end of the first conductor side portion 31 to the lower end of the second conductor side portion 32.

[0052] 1C and 2, the inner cutout 38 is formed in the conductor 30 at a position corresponding to the gap G3 (a position close to the gap G3). More specifically, the inner cutout 38 is formed in the conductor side portions 31 and 32 so as to extend in the Z-axis direction along the center leg edges 23a1 and 23b1 of the center legs 23a and 23b adjacent to the conductor 30. The inner cutout 38 is also formed in the conductor upper portion 33 so as to extend in the X-axis direction along the upper ends of the center legs 23a and 23b. That is, the inner cutout 38 extends along the peripheries of the center legs 23a and 23b.

[0053] The inner cutout 38 faces (is facing) one end of the gap G3 in the X axis direction, and at a position corresponding to the gap G3, the distance between the surface of the conductor 30 and one end of the gap G3 in the X axis direction is a distance that corresponds to the depth of the inner cutout 38. The inner cutout 38 faces (is facing) the other end of the gap G3 in the X axis direction, and at a position corresponding to the gap G3, the distance between the surface of the conductor 30 and the other end of the gap G3 in the X axis direction is a distance that corresponds to the depth of the inner cutout 38.

[0054] The depth and width in the Y-axis direction of inner cutout 38 are the same as those of outer cutouts 36 and 37. Therefore, by applying the relationships described above for outer cutouts 36 and 37 (the ranges of values ​​of W2 / W1, W2 / W3, D / T1 or D / W1, or D>W1) to inner cutout 38 as well, it is possible to prevent leakage magnetic flux generated in gap G3 from impinging on conductor side portions 31 and 32 and conductor upper portion 33 at a position corresponding to gap G3.

[0055] In manufacturing the coil device 10, the first core 20a, the second core 20b, and the conductor 30 shown in Fig. 2 are prepared. Next, one side of the conductor 30 in the Y-axis direction is accommodated inside the first groove portion 24a (second groove portion 24b) of the first core 20a (second core 20b), and the other side of the conductor 30 in the Y-axis direction is accommodated inside the second groove portion 24b (first groove portion 24a) of the second core 20b (first core 20a), and the conductor 30 is sandwiched between the first core 20a and the second core 20b.

[0056] At this time, as shown in FIG. 1B, the first core 20a and the second core 20b are combined with a predetermined gap in the Y-axis direction so that a gap G1 is formed between each of the first outer leg portion 22a and the second outer leg portion 22b located on one side in the X-axis direction, a gap G2 is formed between each of the first outer leg portion 22a and the second outer leg portion 22b located on the other side in the X-axis direction, and a gap G3 is formed between each of the first center leg portion 23a and the second center leg portion 23b.

[0057] As a result, as shown in FIGS. 1B and 1C, the outer cutout portions 36 and 37 face the gaps G1 and G2, and the inner cutout portion 38 faces the gap G3. Then, by joining the first core 20a and the second core 20b with an adhesive or the like, the coil device 10 shown in FIG. 1A is obtained.

[0058] In the coil device 10 according to the present embodiment, the cutout portions 36 to 38 are formed in the conductor 30 at positions corresponding to the gaps G1 to G3. Therefore, at the positions corresponding to the gaps G1 to G3, the surface of the conductor 30 is arranged at a position separated from the gaps G1 to G3 by a distance corresponding to the depth of the cutout portions 36 to 38, and it becomes difficult for the leakage magnetic flux generated in the gaps G1 to G3 to hit the surface of the conductor 30. Therefore, it becomes difficult for eddy currents to be generated on the surface of the conductor 30, and the generation of AC losses due to the eddy currents can be prevented.

[0059] FIG. 4A is a diagram showing the change in wire loss (copper loss) when the width of the gaps G1 to G3 is changed, where the frequency of the alternating current flowing through the conductor 30 is 750 kHz, the current value (peak-to-peak value) of the alternating current is 20 A, and the relative permeability of the material constituting the cores 20a and 20b is 1400. In the figure, the circles indicate the wire loss when the cutout portions 36 to 38 are provided in the conductor 30, and the triangles indicate the wire loss when the cutout portions 36 to 38 are not provided in the conductor 30. As shown in the figure, when the width of the gaps G1 to G3 is changed within the range of 0 < Gap < 250, it can be seen that at any value, the value of the wire loss is smaller when the cutout portions 36 to 38 are provided in the conductor 30 than when the cutout portions 36 to 38 are not provided in the conductor 30.

[0060] 4B is a diagram showing changes in wire loss when the frequency of the AC current flowing through conductor 30 is changed, where the width of gaps G1 to G3 is 225 μm, the current value (peak-to-peak value) of the AC current flowing through conductor 30 is 20 A, and the relative permeability of the material making up cores 20 a and 20 b is 1400. As shown in the figure, when the frequency is changed within the range of 500≦Fsw≦2000, it is clear that the wire loss value is smaller when cutouts 36 to 38 are provided in conductor 30 than when cutouts 36 to 38 are not provided in conductor 30, at all frequency values.

[0061] 4C is a graph showing the change in wire loss when the relative permeability of the material constituting cores 20a and 20b is changed, where the width of gaps G1 to G3 is 225 μm, the current value (peak-to-peak value) of the AC current flowing through conductor 30 is 20 A, and the frequency of the AC current is 750 kHz. As shown in the figure, when the relative permeability is changed within the range of 0<μ≦1400, the wire loss value is smaller when conductor 30 has cutouts 36 to 38 than when conductor 30 does not have cutouts 36 to 38. Ferrite is preferably used as the material constituting cores 20a and 20b.

[0062] 4D is a diagram showing changes in wire loss when the current value (peak-to-peak value) of the AC current flowing through conductor 30 is changed, where the width of gaps G1 to G3 is 225 μm, the relative permeability of the material making up cores 20 a and 20 b is 1400, and the frequency of the AC current flowing through conductor 30 is 750 kHz. As shown in the figure, when the current value (peak-to-peak value) of the AC current is changed within the range of 10≦Ap-p≦40, it is clear that the wire loss value is smaller when cutouts 36 to 38 are provided in conductor 30 than when cutouts 36 to 38 are not provided in conductor 30, regardless of the current value.

[0063] FIG. 4E is a diagram showing the distribution of wire loss in the conductor 30. FIG. 4E(a) shows the distribution of wire loss in the conductor 30 having the cutouts 36-38, and FIG. 4E(b) shows the distribution of wire loss in the conductor 30' having no cutouts 36-38. The magnitude of wire loss is represented by the number of dots shown in the diagram, with the wire loss increasing as the number of dots increases. As is clear from comparing FIGS. 4E(a) and (b), the conductor 30 having the cutouts 36-38 has smaller wire loss at the positions corresponding to the gaps G1-G3 than the conductor 30' having no cutouts 36-38.

[0064] In the coil device 10 according to this embodiment, the conductor 30 has cutouts 36-38 formed at positions corresponding to the gaps G1-G3, and therefore, unlike the prior art, there is no need to change the shape of the first core 20a or the second core 20b to prevent leakage magnetic flux generated in the gaps G1-G3 from impinging on the surface of the conductor 30. This makes it possible to ensure a sufficient volume for the first core 20a or the second core 20b, and to realize a coil device 10 with good inductance characteristics.

[0065] FIG. 4F shows the distribution of magnetic flux in cores 20a and 20b. FIG. 4F(a) shows the distribution of magnetic flux in cores 20a and 20b around conductor 30 having cutouts 36-38, and FIG. 4F(b) shows the distribution of magnetic flux in cores 20a and 20b around conductor 30' without cutouts 36-38. The magnitude of the magnetic flux is represented by the shade of color, with the darker the color, the greater the magnetic flux. Comparing FIGS. 4F(a) and (b) makes it clear that the distribution of magnetic flux in cores 20a and 20b remains almost unchanged in both cases. This shows that providing cutouts 36-38 in conductor 30 does not excessively reduce the magnetic flux in cores 20a and 20b, and good inductance characteristics can be obtained.

[0066] In this embodiment, the outer cutouts 36, 37 (inner cutout 38) are formed in the conductor 30 along the outer leg edges 22a1, 22b1 of the outer legs 22a, 22b (the middle leg edges 23a1, 23b1 of the middle legs 23a, 23b) adjacent to the conductor 30. Therefore, at each portion of the gaps G1, G2 (gap G3) extending along the outer leg edges 22a1, 22b1 of the outer legs 22a, 22b (the middle leg edges 23a1, 23b1 of the middle legs 23a, 23b), leakage magnetic flux generated in the gaps G1, G2 (gap G3) is less likely to impinge on the surface of the conductor 30, effectively preventing eddy currents from being generated on the surface of the conductor 30. Furthermore, the above-mentioned effects can be obtained in a coil device 10 having a so-called EE-type core.

[0067] Furthermore, in this embodiment, the depth of the cutouts 36-38 is greater than the width of the gaps G1-G3. Therefore, at the positions corresponding to the gaps G1-G3, the surface of the conductor 30 can be positioned sufficiently away from the gaps G1-G3. This makes it difficult for leakage magnetic flux generated in the gaps G1-G3 to impinge on the surface of the conductor 30, effectively preventing eddy currents from being generated on the surface of the conductor 30.

[0068] In this embodiment, the cutouts 36-38 are formed as recessed grooves. Therefore, when gaps G1-G3 are formed between the first outer leg 22a and the second outer leg 22b or between the first center leg 23a and the second center leg 23b, the cutouts G1-G3 can be disposed at positions facing the gaps G1-G3. This makes it difficult for leakage magnetic flux generated in the gaps G1-G3 to impinge on the surface of the conductor 30, effectively preventing eddy currents from being generated on the surface of the conductor 30.

[0069] In this embodiment, the conductor 30 has a curved shape, and the cutouts 36-38 are formed on the inner and outer peripheral sides of the conductor 30. The outer cutouts 36, 37 are formed on the outer peripheral side of the conductor 30, which makes it difficult for leakage magnetic flux generated in the gaps G1, G2 formed between the first outer leg 22a and the second outer leg 22b to impinge on the outer peripheral side of the conductor 30, thereby effectively preventing eddy currents from being generated on the surface of the conductor 30. The inner cutout 38 is formed on the inner peripheral side of the conductor 30, which makes it difficult for leakage magnetic flux generated in the gap G3 formed between the first center leg 23a and the second center leg 23b to impinge on the inner peripheral side of the conductor 30, thereby effectively preventing eddy currents from being generated on the surface of the conductor 30.

[0070] In this embodiment, the conductor 30 has mounting portions 34, 35 connected to an external circuit, and the mounting portions 34, 35 are formed with parts of the outer cutouts 36, 37. This makes it difficult for leakage magnetic flux generated in the gaps G1, G2 to impinge on the surfaces of the mounting portions 34, 35, effectively preventing eddy currents from occurring on the surface of the conductor 30.

[0071] Second embodiment The coil device 110 according to the second embodiment of the present invention is similar in configuration to the first embodiment described above, with only the following differences, and provides similar effects. In the drawings, members common to the first embodiment are designated by the same reference numerals, and descriptions of overlapping parts will be omitted.

[0072] As shown in Fig. 5A, coil device 110 has a first core 120a, a second core 120b, and a conductor 130. Coil device 110 has a configuration in which conductor 130 is sandwiched between first core 120a and second core 120b in the vertical direction. As shown in Fig. 6, first core 120a has a pair of first outer legs 122a, 122a and a first groove 124a.

[0073] Each of the pair of first outer legs 122a, 122a has a substantially rectangular parallelepiped shape and is arranged at a predetermined interval in the Y-axis direction. The width of first outer leg 122a in the X-axis direction is greater than its width in the Y-axis direction, and first outer leg 122a is formed to be elongated in the X-axis direction.

[0074] First steps 26a are formed on the first outer legs 122a. More specifically, the first steps 26a are formed at the lower ends of the first outer legs 122a, respectively, and are located inside the first outer legs 122a in the Y-axis direction. The first steps 26a face each other in the Y-axis direction and extend continuously along the X-axis direction.

[0075] The first groove 124a is formed between each of the pair of first outer legs 122a, 122a. The conductor 130 can be disposed in the first groove 124a. The first groove 124a extends around the periphery of the first core 120a in the X-axis direction and the Z-axis direction, approximately at the center of the first core 120a in the Y-axis direction. The depth of the first groove 124a is approximately the same as or greater than the thickness of the conductor 130.

[0076] The first groove portion 124a has a first side portion 241, a second side portion 242, an upper portion 243, and a lower portion 244. The upper portion 243 and the lower portion 244 are formed at positions facing each other along the Z-axis direction and extend along the X-axis direction. As will be described later, the conductor upper portion 33 of the conductor 130 is disposed in the upper portion 243, and the mounting portions 134 and 135 of the conductor 130 are disposed at each end of the lower portion 244 in the Y-axis direction.

[0077] The first side portion 241 and the second side portion 242 are formed at positions facing each other along the X-axis direction and extend along the Z-axis direction. As will be described later, the first conductor side portion 31 of the conductor 130 is arranged on the first side portion 241, and the second conductor side portion 32 of the conductor 130 is arranged on the second side portion 242.

[0078] Second core 120b has a flat plate shape. As shown in Fig. 5B, a gap G4 is formed between second core 120b and first outer leg 122a located on one side in the Y axis direction, and a gap G5 is formed between second core 120b and first outer leg 122a located on the other side in the Y axis direction. Gaps G4 and G5 each extend in the X axis direction and the Y axis direction along the upper end of first outer leg 122a.

[0079] 6, the conductor 130 has a first mounting portion 134 and a second mounting portion 135 in addition to a first conductor side portion 31, a second conductor side portion 32, and an upper conductor portion 33. The first mounting portion 134 and the second mounting portion 135 are formed continuously with (integrally with) one end and the other end of the conductor 130, i.e., the lower end portions of the first conductor side portion 31 and the second conductor side portion 32. The mounting portions 134 and 135 are bent in a direction approximately perpendicular to the conductor side portions 31 and 32, and extend inward in the X-axis direction.

[0080] A first outer cutout 136 and a second outer cutout 137 are formed on the outer periphery (surface) of the conductor 130. The outer cutouts 136, 137 are formed on the surface of the conductor upper portion 33, and extend continuously in the X-axis direction along the extension direction (longitudinal direction) of the conductor upper portion 33.

[0081] The first outer cutout 136 is a chamfered portion formed by chamfering one side (upper corner) in the Y-axis direction of the conductor upper part 33. The second outer cutout 137 is a chamfered portion formed by chamfering the other side (upper corner) in the Y-axis direction of the conductor upper part 33. At the positions where the outer cutouts 136, 137 are formed, the side (upper corner) of the conductor upper part 33 forms an inclined surface (C-surface), and the width of the conductor upper part 33 in the Y-axis direction narrows toward the top.

[0082] 5B, outer cutouts 136, 137 are formed in conductor 130 at positions corresponding to gaps G4, G5 (positions close to gaps G4, G5). More specifically, outer cutouts 136, 137 are formed in conductor 130 so as to extend in the X-axis direction along outer leg edges 122a1, 122b1 of outer legs 122a, 122b adjacent to conductor 130.

[0083] First outer cutout 136 faces obliquely toward the other end of gap G4 in the Y axis direction, and at a position corresponding to gap G4, the distance between the surface of conductor 130 and the other end of gap G4 in the Y axis direction is a distance corresponding to the width W5 or W6 of first outer cutout 136 in the Y axis direction. Second outer cutout 137 faces obliquely toward one end of gap G5 in the Y axis direction, and at a position corresponding to gap G5, the distance between the surface of conductor 130 and one end of gap G5 in the Y axis direction is a distance corresponding to the width W5 or W6 of second outer cutout 137 in the Y axis direction.

[0084] The Y-axis direction width of outer cutouts 136, 137 is preferably larger than the Z-axis direction width of gaps G4, G5, but is not limited to this. The ratio W5 / W4 of the Y-axis direction width W5 of first outer cutout 136 to the Z-axis direction width W4 of gap G4 is preferably 0.5 to 6, more preferably 1 to 5, and particularly preferably 2 to 4. The same applies to the ratio of the Y-axis direction width of second outer cutout 137 to the Z-axis direction width of gap G5.

[0085] The Z-axis direction width of outer cutouts 136, 137 is preferably larger than the Z-axis direction width of gaps G4, G5, but is not limited to this. The ratio W6 / W4 of the Z-axis direction width W6 of first outer cutout 136 to the Z-axis direction width W4 of gap G4 is preferably 0.5 to 6, more preferably 1 to 5, and particularly preferably 2 to 4. The same applies to the ratio of the Z-axis direction width of second outer cutout 137 to the Z-axis direction width of gap G5.

[0086] The ratio W5 / W7 of the Y-axis direction width W5 of first outer cutout 136 to the Y-axis direction width W7 of conductor 130 (FIG. 6) is preferably 0.1 to 0.5, and more preferably 0.2 to 0.3. The same applies to the ratio of the Y-axis direction width W5 of second outer cutout 137 to the Y-axis direction width W7 of conductor 130.

[0087] The ratio W6 / T2 of the width W6 in the Z-axis direction of the first outer cutout 136 to the thickness T2 (FIG. 6) of the conductor 130 is preferably 0.1 to 0.9, and more preferably 0.3 to 0.7. The same applies to the ratio of the width W6 in the Z-axis direction of the second outer cutout 137 to the thickness T2 of the conductor 130.

[0088] In this embodiment, by determining the values ​​of W5 / W4, W6 / W4, W5 / W7 or W6 / T2 as described above, or by making W5 > W4 or W6 / W4, it is possible to prevent leakage magnetic flux generated in gaps G4 and G5 from hitting the upper conductor portion 33 at positions corresponding to gaps G4 and G5.

[0089] In this embodiment, second core 120b has a flat plate shape, and first outer cutouts 136, 137 are formed in conductor 130 at positions corresponding to gaps G4, G5 formed between first legs 122a, 122a and second core 120b. Therefore, in coil device 110 having a so-called EI type core or the like, various effects similar to those of the first embodiment can be obtained.

[0090] Furthermore, in this embodiment, the first outer cutouts 136, 137 are formed by chamfering the sides of the conductor 130. This allows the cutouts 136, 137 to be positioned corresponding to the gaps G4, G5 formed between the first legs 122a, 122a and the flat-plate-shaped second core 120b. This makes it difficult for leakage magnetic flux generated in the gaps G4, G5 to impinge on the surface of the conductor 130 (particularly the conductor upper portion 33), effectively preventing eddy currents from being generated on the surface of the conductor 130.

[0091] Third embodiment The coil device 210 according to the third embodiment of the present invention is similar in configuration to the second embodiment described above, with only the following differences, and provides similar effects. In the drawings, members common to the second embodiment are designated by the same reference numerals, and descriptions of overlapping parts will be omitted.

[0092] As shown in Fig. 7A, coil device 210 has first core 220a, second core 220b, and conductor 230. As is clear from comparing Fig. 8 with Fig. 6, second core 220b differs from second core 120b in the second embodiment in that the thickness in the Z-axis direction is thinner.

[0093] 8, the first core 220a has a pair of first outer legs 222a, 222a, a first center leg 223a, and a pair of first grooves 224a, 224a. Unlike the first outer leg 122a in the second embodiment, each of the pair of first outer legs 222a, 222a does not have a step portion 26a (FIG. 6).

[0094] The first center leg 223a is located between each of the pair of first outer legs 222a, 222a. The first center leg 223a has a shape similar to that of the first outer leg 222a. The width of the first center leg 223a in the Y-axis direction is greater than the width of the first outer leg 222a in the Y-axis direction.

[0095] The first groove portion 224a located on one side in the Y-axis direction is formed between the first outer leg portion 222a and the first center leg portion 223a located on one side in the Y-axis direction. The first groove portion 224a located on the other side in the Y-axis direction is formed between the first outer leg portion 222a and the first center leg portion 223a located on the other side in the Y-axis direction.

[0096] Each of the pair of first grooves 224a, 224a differs from the first groove 124a in the second embodiment in that it does not have a configuration corresponding to the lower portion 244 shown in Fig. 6. The first grooves 224a, 224a can accommodate the conductor upper portions 33, 33 of the conductor 230, respectively.

[0097] The conductor 230 has a pair of conductor upper portions 33, 33, a pair of first conductor side portions 31, 31 connected to one end of the pair of conductor upper portions 33, 33 in the X-axis direction, and a second conductor side portion 232 connected to the other end of the pair of conductor upper portions 33, 33 in the X-axis direction and connecting each of the pair of conductor upper portions 33, 33.

[0098] The pair of conductor upper portions 33, 33 are arranged at a predetermined interval in the Y-axis direction. The second conductor side portion 232 extends in the Y-axis direction, and the pair of conductor upper portions 33, 33 can be connected to each other via the second conductor side portion 232. As shown in Fig. 9, instead of connecting the conductor upper portions 33, 33 with the second conductor side portion 232, the conductor upper portions 33, 33 may each be provided with a second conductor side portion 32, 32, and the coil device 210 may be provided with two conductors 230', 230' formed thereby.

[0099] 7B, a gap G6 is formed between first outer leg 222a and second core 220b located on one side in the Y axis direction, and a gap G7 is formed between first outer leg 222a and second core 220b located on the other side in the Y axis direction. Gaps G6 and G7 each extend in the X axis direction and the Y axis direction along the upper end of first outer leg 222a.

[0100] A gap G8 is formed between the first center leg 223a and the second core 220b. The gap G8 extends in the X-axis direction and the Y-axis direction along the upper end of the first center leg 223a.

[0101] A first outer cutout portion 236 and a second outer cutout portion 237 are formed on the outer periphery (surface) of each of the conductor upper portions 33, 33. The outer cutout portions 236, 237 extend continuously along the extension direction (longitudinal direction) of the conductor upper portion 33. The shapes of the outer cutout portions 236, 237 are similar to the shapes of the outer cutout portions 136, 137 in the second embodiment.

[0102] In the conductor upper portion 33 located on one side in the Y-axis direction, outer cutouts 236, 237 are formed in the conductor 230 at positions corresponding to the gaps G6, G8 (positions close to the gaps G6, G8). More specifically, the first outer cutout 236 faces obliquely with respect to the other end side of the gap G6 in the Y-axis direction, and is formed in the conductor 230 so as to extend in the X-axis direction along the first outer leg edge 222a1 of the first outer leg 222a adjacent to the conductor 230. The second outer cutout 237 faces obliquely with respect to one end side of the gap G8 in the Y-axis direction, and is formed in the conductor 230 so as to extend in the X-axis direction along the first center leg edge 223a1 of the first center leg 223a adjacent to the conductor 230.

[0103] In the conductor upper portion 33 located on the other side in the Y-axis direction, the outer cutouts 236, 237 are formed in the conductor 230 at positions corresponding to the gaps G8, G7 (positions close to the gaps G8, G7). More specifically, the first outer cutout 236 faces obliquely with respect to the other end side of the gap G8 in the Y-axis direction, and is formed in the conductor 230 so as to extend in the X-axis direction along the first center leg edge 223a1 of the first center leg 223a adjacent to the conductor 230. The second outer cutout 237 faces obliquely with respect to one end side of the gap G7 in the Y-axis direction, and is formed in the conductor 230 so as to extend in the X-axis direction along the first outer leg edge 222a1 of the first outer leg 222a adjacent to the conductor 230.

[0104] In this embodiment, the coil device 210 having a so-called EI type core can achieve the same effects as in the first embodiment.

[0105] Fourth embodiment A coil device 310 according to the fourth embodiment of the present invention is similar in configuration to the first embodiment described above, with only the following differences, and provides similar effects. In the drawings, members common to the first embodiment are designated by the same reference numerals, and descriptions of overlapping parts will be omitted.

[0106] 10, the coil device 310 of this embodiment has a conductor 330 and a conductor 40. One of the conductors 330 and 40 functions as a primary coil, and the other functions as a secondary coil. That is, the coil device 310 of this embodiment functions as a coupled coil due to these two conductors 330 and 40.

[0107] The conductor 40 has a substantially U-shape and includes a first conductor side portion 41, a second conductor side portion 42, a conductor upper portion 43, a first mounting portion 44, and a second mounting portion 45. The first conductor side portion 41 and the second conductor side portion 42 are disposed opposite each other in the X-axis direction, and the conductor upper portion 43 connects the upper ends of the conductor side portions 41, 42. The mounting portions 44, 45 are connected continuously (integrally) to the lower ends of the conductor side portions 41, 42, respectively. The mounting portions 44, 45 are bent in a direction substantially perpendicular to the conductor side portions 41, 42 and extend inward in the X-axis direction. In the illustrated example, the thickness of the conductor 40 is smaller than the thickness of the conductor 330.

[0108] 11, conductor 40 is disposed inside (on the inner periphery side) of conductor 330. Conductor 40 is disposed on the periphery of first center legs 23a, 23b so as to surround the periphery of first center legs 23a, 23b, and conductor 330 is disposed outside (on the outer periphery side) of conductor 40 so as to surround the periphery of conductor 40.

[0109] 10, conductor 330 differs from conductor 30 shown in Fig. 2 in that conductor 330 does not have inner cutout 38 formed on its back surface. In this embodiment, conductor 40 is interposed between conductor 330 and gap G3 (Fig. 1B), and therefore conductor 330 does not face gap G3, and conductor 330 is less susceptible to the effects of leakage magnetic flux generated in gap G3.

[0110] In this embodiment, the coupled coil having two conductors 330 and 40 can achieve the same effects as in the first embodiment.

[0111] The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the present invention.

[0112] In the first embodiment, either one of the outer cutouts 36, 37 and the inner cutout 38 may be omitted.

[0113] In the first embodiment, the positions of the cutouts 36 to 38 in the Y-axis direction may be changed as appropriate in accordance with the positions of the gaps G1 to G3 in the Y-axis direction.

[0114] In the first embodiment, the first core 20a and the second core 20b are configured as separate bodies, but they may be configured as an integrated body, with the first core 20a functioning as the first core section and the second core 20b functioning as the second core section, as in the second to fourth embodiments.

[0115] In the first embodiment, the mounting portions 34, 35 are disposed between the first core 20a and the second core 20b, but at least a portion of the mounting portions 34, 35 may be disposed outside the cores 20a, 20b. The same applies to the fourth embodiment.

[0116] In the first embodiment, the notches 36 to 38 extend continuously along the extension direction of the conductor 30, but they may extend intermittently. The same applies to the fourth embodiment. In the second embodiment, the notches 136 and 137 extend continuously along the extension direction of the conductor 130, but they may extend intermittently. The same applies to the third embodiment. [Explanation of symbols]

[0117] 10, 110, 210, 310... Coil device 20a, 120a, 220a...1st core 20b, 120b, 220b...second core 21a...First base section 21b...Second base part 22a, 122a, 222a...first outer leg part 22a1, 122a1, 222a1...first outer leg edge 22b…Second outer leg 22b1,122b1...2nd outer leg edge 23a, 223a...first middle leg 23a1, 223a1...Edge of the first middle leg 23b…Second middle leg 23b1...Edge of second middle leg 24a, 124a...first groove part 24b…Second groove part 241...first lateral part 242…Second side part 243...Upper part 244…Lower part 25a...First side groove part 25b…Second side groove part 26a...Step 30, 30', 130, 230, 230', 330, 40... conductor 31, 41...first conductor side 32, 232, 42...Second conductor side 33, 43...Upper conductor 34, 134, 44...First mounting section 35, 135, 45...Second mounting section 36, 136, 236...First outer notch 37, 137, 237...Second outer notch 38...Inner cutout

Claims

1. a first core portion having a plurality of first legs; a second core portion disposed between the first leg portions and the second core portion and forming a plurality of gaps therebetween; a conductor at least a portion of which is disposed between the first core portion and the second core portion, a plurality of notches are formed in the conductor at positions corresponding to all of the gaps; the plurality of cutout portions include a first outer cutout portion and a second outer cutout portion, which are outer cutout portions formed on an outer peripheral surface of the conductor; When a direction in which the first core portion and the second core portion face each other is defined as a Z-axis direction, a direction in which the conductor upper portion of the conductor extends is defined as an X-axis direction, and a direction perpendicular to the Z-axis direction and the X-axis direction is defined as a Y-axis direction, the first outer cutout portion is a chamfered portion formed by chamfering one side portion of the upper portion of the conductor in the Y-axis direction, the second outer cutout portion is a chamfered portion formed by chamfering a side portion of the upper portion of the conductor on the other side in the Y-axis direction, the relationship between the width (W5) of the outer cutout portion in the Y-axis direction and the width (W4) of the gap in the Z-axis direction is W5>W4; or The ratio (W6 / W4) of the width (W6) of the outer cutout portion in the Z-axis direction to the width (W4) of the gap in the Z-axis direction is 0.5 to 6. Coil device.

2. The coil device according to claim 1 , wherein the plurality of cutouts include inner cutouts formed in an inner peripheral surface of the conductor.

3. The coil device according to claim 2 , wherein the depth of the inner cutout portion is equal to the depth of the outer cutout portion.

4. A coil device as described in claim 1, wherein the second core portion has a flat plate shape.

5. A coil device described in any one of claims 1 to 4, wherein each of the first outer cutout portion and the second outer cutout portion is formed in the conductor along the edge of the first leg portion adjacent to the conductor.

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