Coil device

Abstract

To provide a coil device having a simple configuration and high heat dissipation.SOLUTION: A coil device 1 includes a bobbin 2, a first winding part disposed on an outer peripheral surface of the bobbin 2, a second winding part 40 disposed directly or indirectly on an outer peripheral surface of the first winding part, a first core 5a and a second core 6a attached to the bobbin 2, a case 8 that houses at least the bobbin 2, and a synthetic resin filled in the case 8. The first core side 5a has a first base portion 50 and a pair of first outer leg portions 51 that protrude from the first base portion 50 and face each other in a first direction perpendicular to the axial direction of the bobbin 2. The second core side 6a has a second base portion 60 and a pair of second outer leg portions 61 that protrude from the second base portion 60 and face each other in the first direction. The first outer leg portion 51 is separated from the second outer leg portion 61 such that a gap 12 is formed between the first outer leg portion 51 and the second outer leg portion 61 in a second direction perpendicular to the axial direction of the bobbin 2 and the first direction.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a coil device. [Background technology]

[0002] Patent Document 1 discloses a technique for cooling a coil device in which a through hole is formed in the core and cooling air is introduced into the inside of the core through the through hole. By introducing cooling air into the inside of the core through the through hole, it becomes possible to cool the core and the coil, and to improve the heat dissipation performance of the coil device. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-156351 Summary of the Invention [Problem to be solved by the invention]

[0004] However, forming a through hole in the core makes the core structure complicated, and the heat dissipation capability of the coil is not sufficient compared to the heat dissipation capability of the core.

[0005] The present disclosure provides a coil device having a simple configuration and high heat dissipation properties. [Means for solving the problem]

[0006] The coil device of the present disclosure is Bobbin and a first winding portion disposed on the outer peripheral surface of the bobbin; a second winding portion disposed directly or indirectly on an outer peripheral surface of the first winding portion; a first core and a second core attached to the bobbin; a case that accommodates at least the bobbin; a resin filled in the case, the first core has a first base portion and a pair of first outer leg portions that protrude from the first base portion and face each other in a first direction perpendicular to the axial direction of the bobbin, the second core has a second base portion and a pair of second outer legs that protrude from the second base portion and face each other in the first direction, The first outer leg is spaced from the second outer leg so that a gap is formed between the first outer leg and the second outer leg in a second direction perpendicular to the axial direction and the first direction. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a perspective view of a coil device according to a first embodiment. [Figure 2] FIG. 2 is an exploded perspective view of the coil device shown in FIG. [Figure 3] FIG. 3 is an exploded perspective view of the bobbin shown in FIG. [Figure 4] 4 is a perspective view of the bobbin and the winding portion shown in FIG. 2. FIG. [Figure 5] FIG. 5 is a cross-sectional view taken along line VV shown in FIG. [Figure 6] FIG. 6 is a cross-sectional view taken along line VI-VI shown in FIG. [Figure 7] FIG. 7 is a plan view of the bobbin to which the first core, the second core, and the third core are attached. [Figure 8] FIG. 8 is a side view of the coil device shown in FIG. 1 with the case omitted. [Figure 9] FIG. 9 is a perspective view of the coil device shown in FIG. 1 with the case omitted. [Figure 10] FIG. 10 is a perspective view of the case shown in FIG. [Figure 11] FIG. 11 is a perspective view of a coil device according to the second embodiment. [Figure 12] FIG. 12 is a perspective view of the bobbin of the coil device shown in FIG. [Figure 13] FIG. 13 is a side view of the coil device shown in FIG. 11 with the case omitted. [Figure 14]FIG. 14 is a cross-sectional view taken along line XIV-XIV shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the contents shown in the drawings are merely shown schematically and exemplarily to facilitate understanding of the present invention, and the appearance and dimensional ratios may differ from the actual product. Furthermore, the present invention is not limited to the following embodiments.

[0009] (First embodiment) The coil device 1 of the first embodiment shown in Fig. 1 is a composite coil device having both the functions of a transformer and an inductor, and is mounted in the power supply circuit of an electrical device, etc. As shown in Fig. 2, the coil device 1 has at least a bobbin 2, a first wire 3, a second wire 4, first cores 5a-5b, second cores 6a-6b, a case 8 (Fig. 1), and resin 9 (Fig. 5). The coil device 1 further has third cores 7a-7b, a first heat dissipation member 10, and second heat dissipation members 11a-11b, but these components are not essential and may be omitted.

[0010] The first cores 5a-5b, second cores 6a-6b, and third cores 7a-7b are all E-shaped cores and are attached to the bobbin 2 (FIG. 9). The first cores 5a-5b, second cores 6a-6b, and third cores 7a-7b have the same shape, but may have different shapes. The first core 5a is combined with the first core 5b, the second core 6a is combined with the second core 6b, and the third core 7a is combined with the third core 7b. The second core 6a is adjacent to the first core 5a, and the third core 7a is adjacent to the second core 6a. The second core 6b is adjacent to the first core 5b, and the third core 7b is adjacent to the second core 6b.

[0011] Each of the first cores 5a to 5b has a base portion 50, a pair of outer legs 51, and a center leg portion 52. Each of the second cores 6a to 6b has a base portion 60, a pair of outer legs 61, and a center leg portion 62. Each of the third cores 7a to 7b has a base portion 70, a pair of outer legs 71, and a center leg portion 72.

[0012] In the following description, the axis along the direction in which the pair of outer legs 51 face each other (first direction) is referred to as the X-axis. The axis along the direction in which the first core 5a and the second core 6a face each other is referred to as the Y-axis. The axis corresponding to the axial direction of the bobbin 2 is referred to as the Z-axis. The X-axis, Y-axis, and Z-axis are perpendicular to each other.

[0013] In this disclosure, the positive side of the Z axis is referred to as "upward," and the negative side of the Z axis is referred to as "downward." However, upward in the Z axis direction does not necessarily coincide with upward in the vertical direction. Also, downward in the Z axis direction does not necessarily coincide with downward in the vertical direction.

[0014] The pair of outer legs 51 protrude from the base portion 50 and face each other in a direction (X-axis direction) perpendicular to the axial direction of the bobbin 2. The pair of outer legs 51 are located at both ends of the base portion 50 in the X-axis direction and extend in a direction (Z-axis direction) perpendicular to the base portion 50.

[0015] However, in this disclosure, "perpendicular" does not only refer to strict perpendicularity, but also includes a state in which there is an error of ±Δθ° (not particularly limited, for example, Δθ=3) or less from strict perpendicularity. Furthermore, "parallel" does not only refer to strict parallelity, but also includes a state in which there is an error of ±Δθ° (not particularly limited, for example, Δθ=3) or less from strict parallelity.

[0016] The middle leg 52 is located between the pair of outer legs 51 and protrudes from the base 50. The middle leg 52 extends in a direction perpendicular to the base 50.

[0017] The pair of outer legs 61 protrude from the base portion 60 and face each other in the X-axis direction, which is perpendicular to the axial direction of the bobbin 2. The pair of outer legs 61 are located at both ends of the base portion 60 in the X-axis direction and extend in a direction perpendicular to the base portion 60 (the Z-axis direction). The center leg 62 is located between the pair of outer legs 61 and protrudes from the base portion 60. The center leg 62 extends in a direction perpendicular to the base portion 60.

[0018] The pair of outer legs 71 protrude from the base portion 70 and face each other in the X-axis direction, which is perpendicular to the axial direction of the bobbin 2. The pair of outer legs 71 are located at both ends of the base portion 70 in the X-axis direction and extend in a direction perpendicular to the base portion 70 (the Z-axis direction). The middle leg 72 is located between the pair of outer legs 71 and protrudes from the base portion 70. The middle leg 72 extends in a direction perpendicular to the base portion 70.

[0019] The cross-sectional shape (cross-section perpendicular to the Z axis) of the outer legs 51, 61, and 71 is rectangular, but may be square, other polygonal, circular, elliptical, or other shapes. Also, the cross-sectional shape of the middle legs 52, 62, and 72 is rectangular, but may be square, other polygonal, circular, elliptical, or other shapes.

[0020] Each of the first cores 5a-5b may be made up of multiple cores. For example, each of the first cores 5a-5b may be made up of multiple I-shaped cores combined in an E shape. Alternatively, each of the first cores 5a-5b may be made up of a U-shaped core and an I-shaped core combined in an E shape. The same applies to the second cores 6a-6b and the third cores 7a-7b.

[0021] Furthermore, one of the first cores 5a and 5b may be an E-shaped core, and the other an I-shaped core. The same applies to the second cores 6a to 6b and the third cores 7a to 7b.

[0022] The first core 5a, the second core 6a, and the third core 7a are arranged at intervals along the Y-axis direction, and the first core 5b, the second core 6b, and the third core 7b are arranged at intervals along the Y-axis direction.

[0023] When the first cores 5a and 5b are attached to the bobbin 2, the tips of the pair of outer legs 51 of the first core 5a may be in contact with the tips of the pair of outer legs 51 of the first core 5b, or may be spaced apart so as to form a gap therebetween. When the second cores 6a and 6b are attached to the bobbin 2, the tips of the pair of outer legs 61 of the second core 6a may be in contact with the tips of the pair of outer legs 61 of the second core 6b, or may be spaced apart so as to form a gap therebetween. When the third cores 7a and 7b are attached to the bobbin 2, the tips of the pair of outer legs 71 of the third core 7a may be in contact with the tips of the pair of outer legs 71 of the third core 7b, or may be spaced apart so as to form a gap therebetween.

[0024] When the first cores 5a and 5b are attached to the bobbin 2, the tip of the center leg 52 of the first core 5a may be in contact with the tip of the center leg 52 of the first core 5b, or may be spaced apart so as to form a gap therebetween. When the second cores 6a and 6b are attached to the bobbin 2, the tip of the center leg 62 of the second core 6a may be in contact with the tip of the center leg 62 of the second core 6b, or may be spaced apart so as to form a gap therebetween. When the third cores 7a and 7b are attached to the bobbin 2, the tip of the center leg 72 of the third core 7a may be in contact with the tip of the center leg 72 of the third core 7b, or may be spaced apart so as to form a gap therebetween.

[0025] The first cores 5a-5b are formed of a material containing a magnetic material and a resin. The magnetic material constituting the first cores 5a-5b is not particularly limited, but may be, for example, ferrite (Ni-Zn ferrite, Mn-Zn ferrite, etc.) or a metallic magnetic material (Fe-Ni alloy, Fe-Si alloy, Fe-Si-Cr alloy, Fe-Co alloy, Fe-Si-Al alloy, amorphous iron, etc.). The resin constituting the first cores 5a-5b is not particularly limited, but may be, for example, epoxy resin, phenol resin, polyester resin, polyurethane resin, polyimide resin, etc. The first cores 5a-5b may be a sintered metallic magnetic material. The same applies to the materials constituting the second cores 6a-6b and the third cores 7a-7b.

[0026] As shown in FIG. 4, the first wire 3 has a winding portion 30 and lead-out portions 31a to 31b drawn out from the winding portion 30. The winding portion 30 is disposed directly or indirectly on the outer peripheral surface of the first bobbin 20 that constitutes the bobbin 2. The winding portion 30 is formed by spirally winding the first wire 3 around the outer peripheral surface of the first bobbin 20. The winding axis direction of the winding portion 30 corresponds to the Z-axis direction. The lead-out portion 31a is one end of the first wire 3, and the lead-out portion 31b is the other end of the first wire 3. Terminals are attached to the lead-out portions 31a and 31b.

[0027] The second wire 4 has a winding portion 40 and lead-out portions 41a to 41b drawn out from the winding portion 40. As shown in FIG. 2, at least a portion of the winding portion 40 (in this embodiment, a portion of the winding portion 40) is disposed directly or indirectly on the outer circumferential surface of the winding portion 30. In this embodiment, a portion of the winding portion 40 is disposed directly or indirectly on the outer circumferential surface of the main body 250 of the second bobbin 24 that constitutes the bobbin 2. The winding portion 40 is formed by spirally winding the second wire 4 around the outer circumferential surface of the winding portion 30 and the outer circumferential surface of the main body 250. The winding axis direction of the winding portion 40 corresponds to the Z-axis direction. One of the winding portions 30 and 40 functions as a primary coil, and the other functions as a secondary coil.

[0028] 4, the lead-out portion 41a is one end of the second wire 4, and the lead-out portion 41b is the other end of the second wire 4. Terminals are attached to the lead-out portions 41a and 41b.

[0029] The first wire 3 and the second wire 4 are, for example, insulated wires. The first wire 3 and the second wire 4 are known winding wires such as AIW (polyamideimide copper wire), UEW (polyurethane copper wire), and PEW (polyester copper wire). The first wire 3 and the second wire 4 are round wires, but may also be square wires, twisted wires, Litz wires, braided wires, etc. The material constituting the core wires of the first wire 3 and the second wire 4 is not particularly limited, but may be, for example, copper, copper alloy, silver, or nickel. The diameter of the first wire 3 or the second wire 4 is not particularly limited, but may be, for example, 10 to 100 μm. The diameter of the first wire 3 is equal to the diameter of the second wire 4, but may be different.

[0030] In the present disclosure, the terms "equal," "comparable," or "similar" do not refer only to a state in which the physical quantities of the objects being compared are strictly equal, equivalent, or similar; the terms "equal," "comparable," or "similar" also include a state in which there is an error of ±Δ% or less (not particularly limited, for example, Δ=7, 5, or 3) between the physical quantities of the objects being compared.

[0031] As shown in Fig. 6, at least one of the winding section 30 and the winding section 40 has a transformer section 13 that functions as a transformer and an inductor section 14 that functions as an inductor. The transformer section 13 includes at least the winding section 30 and the winding section 40 that is laminated on the winding section 30 along the radial direction of the winding section 30. The transformer section 13 includes first cores 5a-5b and second cores 6a-6b. The inductor section 14 includes at least the winding section 40. The inductor section 14 includes third cores 7a-7b.

[0032] The winding portion 30 has an overlapping portion 32 and a non-overlapping portion 33. The overlapping portion 32 overlaps with the winding portion 40 along the radial direction of the winding portion 30 and is covered by the winding portion 40. The non-overlapping portion 33 does not overlap with the winding portion 40 along the radial direction of the winding portion 30 and protrudes downward from the winding portion 40 along the winding axis direction of the winding portion 30. The number of layers of the non-overlapping portion 33 along the winding axis direction of the winding portion 30 is two, which is fewer than the number of layers of the overlapping portion 32 along the winding axis direction of the winding portion 30. However, the number of layers of the non-overlapping portion 33 along the winding axis direction of the winding portion 30 may be equal to or greater than the number of layers of the overlapping portion 32 along the winding axis direction of the winding portion 30.

[0033] A part of the bobbin 2 (the middle flange portion 213 of the first bobbin 20) is disposed between the overlapping portion 32 and the non-overlapping portion 33. Therefore, the overlapping portion 32 and the non-overlapping portion 33 are spaced apart along the winding axis direction of the winding portion 30.

[0034] The non-overlapping portion 33 is disposed inside the resin 9 filled in the case 8. In this embodiment, the entire non-overlapping portion 33 is disposed inside the resin 9, but a part of the non-overlapping portion 33 (for example, an upper end portion of the non-overlapping portion 33) may be exposed from the resin 9.

[0035] On the other hand, the overlapping portion 32 is disposed outside the resin 9 and is exposed from the resin 9. In this embodiment, the entire overlapping portion 32 is exposed from the resin 9, but a part of the overlapping portion 32 (for example, the lower end portion of the overlapping portion 32) may be disposed inside the resin 9.

[0036] As shown in Fig. 3, the bobbin 2 has a first bobbin 20 and a second bobbin 24. The bobbin 2 is made of plastic, such as PPS, PET, PBT, or LCP, or other insulating material. The bobbin 2 is made of two members, the first bobbin 20 and the second bobbin 24, but may also be made of a single member. The first bobbin 20 has a main body 210, flange portions 211 and 212, an intermediate flange portion 213, wall portions 214 to 219, a protrusion 220, a hook portion 221, guides 222 and 223, and a through-hole 224.

[0037] The main body 210 is a cylinder having a through hole 224. The through hole 224 extends along the axial direction of the main body 210. A communication hole is formed in the main body 210, penetrating the main body 210 from the outer peripheral surface to the inner peripheral surface of the main body 210. When the inside of the case 8 (FIG. 6) is filled with resin 9, the resin 9 flows from the outside to the inside of the main body 210 through the communication hole. The shape of the main body 210 in a plan view is not particularly limited, but has an elongated shape in the Y-axis direction.

[0038] Flange portion 211 is formed at the upper end of main body 210 and protrudes from the outer peripheral surface of main body 210 along the radial direction of main body 210. Flange portion 212 is formed at the lower end of main body 210 and protrudes from the outer peripheral surface of main body 210 along the radial direction of main body 210. Intermediate flange portion 213 is located between flange portion 211 and flange portion 212 and protrudes from the outer peripheral surface of main body 210 along the radial direction of main body 210.

[0039] As shown in FIG. 4, the first wire 3 is wound around the outer circumferential surface of the main body 210, forming a wound portion 30. An overlapping portion 32 is disposed between the flange portion 211 and the intermediate flange portion 213, and a non-overlapping portion 33 is disposed between the intermediate flange portion 213 and the flange portion 212. In other words, the intermediate flange portion 213 is located between the overlapping portion 32 and the non-overlapping portion 33, separating them. As shown in FIG. 5, in this embodiment, the resin 9 is filled into the case 8 so that the surface (top surface) of the resin 9 is located at the position of the intermediate flange portion 213. However, the position of the surface of the resin 9 may be lower or higher than the position of the intermediate flange portion 213.

[0040] As shown in Fig. 3, wall portion 214 is located at one end of flange portion 211 in the Y-axis direction, and protrudes upward from the upper surface of flange portion 211. Wall portion 215 is located at the other end of flange portion 211 in the Y-axis direction, and protrudes upward from the upper surface of flange portion 211. In the example shown in Fig. 3, wall portion 215 has a through-hole (Fig. 7) formed therein.

[0041] Wall portion 216 is located at one end of flange portion 212 in the Y-axis direction, and protrudes downward from the lower surface of flange portion 212. Wall portion 217 is located at the other end of flange portion 212 in the Y-axis direction, and protrudes downward from the lower surface of flange portion 212.

[0042] Wall portion 218 is located between wall portion 214 and wall portion 215, and protrudes upward from the upper surface of flange portion 211. Wall portion 219 is located between wall portion 216 and wall portion 217, and protrudes downward from the lower surface of flange portion 212.

[0043] 7 and 8, the base portion 50 of the first core 5a is disposed between the wall portion 214 and the wall portion 218. The base portion 60 of the second core 6a is disposed between the wall portion 215 and the wall portion 218. The base portion 50 of the first core 5b is disposed between the wall portion 216 and the wall portion 219. The base portion 60 of the second core 6b is disposed between the wall portion 217 and the wall portion 219.

[0044] As shown in Fig. 3, the pair of protrusions 220 protrude from the wall portion 214 and extend in a direction away from the second bobbin 24. The pair of hook portions 221 protrude from the pair of protrusions 220 so as to approach each other. The hook portions 221 are bent in an L-shape. The lead-out portion 31a (Fig. 7) engages with one of the hook portions 221, and the lead-out portion 31b engages with the other hook portion 221.

[0045] Guides 222 and 223 are adjacent to each other and formed on the outer peripheral surface of main body 210. Guides 222 and 223 extend along the axial direction of main body 210. As shown in FIG. 7, lead-out portion 31b is drawn upward from winding portion 30 while passing between guides 222 and 223. Note that, as shown in FIG. 6, lead-out portion 31b is drawn upward from non-overlapping portion 33. On the other hand, lead-out portion 31a is drawn upward from the upper end of overlapping portion 33.

[0046] As shown in Fig. 3, the second bobbin 24 has a main body 250, flange portions 251-252, an intermediate flange portion 253, wall portions 254-257, a protrusion 260, a hook portion 261, and a convex portion 265. The main body 250 is bent in a C-shape in plan view. A communication hole is formed in the main body 250, penetrating the main body 250 from its outer peripheral surface to its inner peripheral surface. When the inside of the case 8 (Fig. 6) is filled with resin 9, the resin 9 flows from the outside to the inside of the main body 250 through the communication hole.

[0047] The flange portion 251 is formed at the upper end of the main body 250 and protrudes from the outer peripheral surface of the main body 250 along the radial direction of the main body 250. The flange portion 252 is formed at the lower end of the main body 250 and protrudes from the outer peripheral surface of the main body 250 along the radial direction of the main body 250. The intermediate flange portion 253 is located between the flange portions 251 and 252 and protrudes from the outer peripheral surface of the main body 250 along the radial direction of the main body 250. As shown in FIG. 4, the intermediate flange portion 253 is combined with the intermediate flange portion 213. As shown in FIG. 6, in this embodiment, the resin 9 is filled into the case 8 so that the surface (upper surface) of the resin 9 is located at the position of the intermediate flange portion 253. However, the position of the surface of the resin 9 may be lower or higher than the position of the intermediate flange portion 253.

[0048] 2 and 4, when the second bobbin 24 is combined with the first bobbin 20, the second wire 4 can be wound around the outer circumferential surface of the main body 250 and the outer circumferential surface of the winding portion 30. As a result, the winding portion 40 is formed on the outer circumferential surface of the main body 250 and the outer circumferential surface of the winding portion 30. The winding portion 40 is disposed between the flange portion 251 and the intermediate flange portion 253, and is not disposed between the intermediate flange portion 253 and the flange portion 252.

[0049] 3, wall portion 254 is located at one end of flange portion 251 in the Y-axis direction, and protrudes upward from the upper surface of flange portion 251. Wall portion 255 is located at the other end of flange portion 251 in the Y-axis direction, and protrudes upward from the upper surface of flange portion 251.

[0050] Wall portion 256 is located at one end of flange portion 252 in the Y-axis direction, and protrudes downward from the lower surface of flange portion 252. Wall portion 257 is located at the other end of flange portion 252 in the Y-axis direction, and protrudes downward from the lower surface of flange portion 252. As shown in FIG. 4 , wall portion 254 is combined with wall portion 215, and wall portion 256 is combined with wall portion 217.

[0051] 8, the base portion 70 of the third core 7a is disposed between the wall portion 254 and the wall portion 255. The base portion 70 of the third core 7b is disposed between the wall portion 256 and the wall portion 257.

[0052] As shown in FIG. 3, the pair of protrusions 260 protrude from the wall portion 255 and extend in a direction away from the first bobbin 20. The pair of hook portions 261 protrude from the pair of protrusions 260 so as to approach each other. The hook portions 261 are bent in an L shape. The lead-out portion 41a (FIG. 7) engages with one of the hook portions 261, and the lead-out portion 41b engages with the other hook portion 261. The lead-out portions 41a and 41b are drawn upward from the upper end of the winding portion 40 between the flange portion 251 and the intermediate flange portion 253.

[0053] The plurality of protrusions 265 are formed on the outer peripheral surface of the main body 250, and extend along the axial direction of the main body 250 between the flange portion 251 and the intermediate flange portion 253. The plurality of protrusions 265 protrude from the outer peripheral surface of the main body 250 along the radial direction of the main body 250. Because the plurality of protrusions 265 are formed on the outer peripheral surface of the main body 250, the winding portion 40 (FIG. 4) is disposed on the outer peripheral surface of the main body 250 via the plurality of protrusions 265.

[0054] As shown in FIG. 2, the first heat dissipation member 10 is made of a flat, plate-like member. The material constituting the first heat dissipation member 10 is not particularly limited, but may be a metal such as aluminum, copper, or silver. The surface (upper surface) of the first heat dissipation member 10 is formed with irregularities 100. The irregularities 100 are formed in the shape of slits. The irregularities 100 have a plurality of protrusions extending in the Y-axis direction and a plurality of recesses extending in the Y-axis direction. The plurality of protrusions and recesses are arranged in the X-axis direction.

[0055] 1, the first heat dissipation member 10 is disposed on the base portion 50 of the first core 5a, the base portion 60 of the second core 6a, and the base portion 70 of the third core 7a. The first heat dissipation member 10 is disposed at least directly on the base portions 50 and 60, but may also be disposed indirectly on the base portions 50 and 60. The first heat dissipation member 10 is attached to the base portions 50, 60, and 70 by, for example, an adhesive.

[0056] As shown in FIG. 2, the second heat dissipation members 11a and 11b are formed in an E-shape. The material constituting the second heat dissipation members 11a and 11b is not particularly limited, but may be a metal such as aluminum, copper, or silver. The second heat dissipation members 11a and 11b have the same shape, but may also have different shapes. The second heat dissipation member 11a is combined with the second heat dissipation member 11b. The second heat dissipation members 11a and 11b each have a base portion 110, a pair of outer legs 111, and a center leg portion 112.

[0057] The pair of outer legs 111 protrude from the base portion 110 and face each other in the X-axis direction. The pair of outer legs 111 are located at both ends of the base portion 110 in the X-axis direction and extend in a direction perpendicular to the base portion 110 (the Z-axis direction). The middle leg 112 is located between the pair of outer legs 111 and protrudes from the base portion 110. The middle leg 112 extends in a direction perpendicular to the base portion 110.

[0058] The tips of the pair of outer legs 111 of the second heat dissipation member 11a may be in contact with the tips of the pair of outer legs 111 of the second heat dissipation member 11b, or may be spaced apart so as to form a gap therebetween. The tips of the middle legs 112 of the second heat dissipation member 11a may be in contact with the tips of the middle legs 112 of the second heat dissipation member 11b, or may be spaced apart so as to form a gap therebetween.

[0059] Concave and convex portions 113 are formed on the end surfaces of the second heat dissipation members 11a and 11b in the Y-axis direction. The concave and convex portions 113 are formed in a slit shape. The concave and convex portions 113 have a plurality of convex portions extending in the Z-axis direction and a plurality of concave portions extending in the Z-axis direction. The plurality of convex portions and the plurality of concave portions are arranged in the X-axis direction.

[0060] As shown in FIG. 9, the second heat dissipation member 11a is disposed on the end face of the third core 7a in the Y axis direction. The second heat dissipation member 11a is disposed directly on the end face of the third core 7a in the Y axis direction, but may also be disposed indirectly on the end face of the third core 7a in the Y axis direction. The second heat dissipation member 11b is disposed on the end face of the third core 7b in the Y axis direction. The second heat dissipation members 11a and 11b are attached to the third cores 7a and 7b, for example, by adhesive.

[0061] 10, the case 8 has a bottom plate 80, side plates 81a to 81d, and a communication portion 82. The case 8 is made of a metal with excellent cooling properties, such as aluminum. The case 8 accommodates at least the bobbin 2.

[0062] The side plates 81a to 81d extend from the outer periphery of the bottom plate 80 in a direction perpendicular (upward) to the bottom plate 80. The bottom plates 81a and 81b face each other in the Y-axis direction and bulge outward from the case 8 according to the shape of the bobbin 2. The bottom plates 81c and 81d face each other in the X-axis direction.

[0063] The communicating portion 82 is formed in a slit shape and extends elongatedly in the X-axis direction when viewed in the Y-axis direction. The communicating portion 82 communicates the bottom plate 81 in the Y-axis direction from the outer surface to the inner surface of the bottom plate 81a or 81b. In this embodiment, the communicating portion 82 is a through-hole that penetrates the bottom plate 81a or 81b. However, the communicating portion 82 is not limited to a through-hole, and may be a notch that cuts out the outer periphery of the bottom plate 81a or 81b. Alternatively, the communicating portion 82 may be a recess that is recessed from the outer periphery of the bottom plate 81a or 81b.

[0064] In the example shown in FIG. 10 , two communication sections 82 are arranged above and below the bottom plate 81a. Similarly, two communication sections 82 are arranged above and below the bottom plate 81b. The shape of the communication sections 82 when viewed from a direction perpendicular to the side plate 81a or 81b is substantially elliptical or rectangular, but may be, for example, circular, square, other polygonal, or other shapes. Furthermore, the number of communication sections 82 on the bottom plate 81a or 81b is not limited to two and may be one, or three or more. For example, when viewed from a direction perpendicular to the side plate 81a or 81b, multiple circular communication sections 82 may be arranged in the X-axis direction.

[0065] 6, the communication portion 82 is located at a position spaced apart from the surface (upper surface) of the resin 9 filled in the case 8 in a direction (upward) toward the opening of the case 8. The resin 9 is filled in the case 8 up to the same position as the communication portion 82, but may also be filled up to a position below the position of the communication portion 82. The resin 9 is not particularly limited, and may be made of, for example, a silicone resin, a urethane resin, or an epoxy resin.

[0066] At least a portion of the outer peripheral surface of the winding portion 40 faces the outside of the case 8 through the communication portion 82. Furthermore, the communication portion 82 is located in a position such that the outer peripheral surface of the winding portion 40 can be seen through the communication portion 82 from the outside of the case 8. Therefore, when cooling air is caused to flow in the Y-axis direction toward the coil device 1, at least a portion of the cooling air flows into the inside of the case 8 through the communication portion 82. Then, at least a portion of the cooling air hits the winding portion 40, thereby cooling the winding portion 40.

[0067] As shown in FIG. 8 , in this embodiment, the outer leg 51 of the first core 5a is spaced apart from the outer leg 61 of the second core 6a in the Y-axis direction. Furthermore, the outer leg 51 of the first core 5b is spaced apart from the outer leg 61 of the second core 6b in the Y-axis direction. Therefore, a gap 12 is formed between the outer legs 51 and 61. The width of the gap 12 in the Y-axis direction is equal to or greater than the width of the wall portion 218 of the first bobbin 20 in the Y-axis direction. For example, the width of the gap 12 in the Y-axis direction is equal to or greater than half the diameter of the first wire 3 or the second wire 4. In addition to being formed between the outer legs 51 and 61, the gap 12 is also formed between the base portion 50 and the base portion 60.

[0068] As described above, at least a portion of the cooling air flows into the inside of the case 8 through the communication portion 82. At least a portion of the cooling air flows out to the outside of the cores 5a and 5b through the gap 12 between the outer leg portion 51 and the outer leg portion 61. In this manner, in this embodiment, the communication portion 82 serves as an inlet that introduces the cooling air into the inside of the case 8, while the gap 12 serves as an outlet that guides the cooling air to the outside of the cores 5a and 5b. Therefore, a flow path for the cooling air is formed from the communication portion 82 to the gap 12, passing around the outer peripheral surface of the winding portion 40.

[0069] In this embodiment, the outer legs 61 of the second cores 6a and 6b are spaced apart from the outer legs 71 of the third cores 7a and 7b in the Y-axis direction. Therefore, a gap that functions as a flow path for cooling air is also formed between the outer legs 61 and 71.

[0070] Next, a manufacturing method of the coil device 1 will be described. First, the first wire 3 (FIG. 4) is wound around the outer circumferential surface of the main body 210 of the first bobbin 20 shown in FIG. 3 to form the winding portion 30. Then, the lead-out portions 31a and 31b (FIG. 4) are drawn out from the winding portion 30 so as to pass through the hook portion 221. Next, as shown in FIG. 4, the second bobbin 24 is combined with the first bobbin 20 around which the first wire 3 is wound. Next, the second wire 4 is wound around the outer circumferential surface of the winding portion 30 and the outer circumferential surface of the main body 250 of the second bobbin 24 to form the winding portion 40 shown in FIG. 2. Then, the lead-out portions 41a and 41b are drawn out from the winding portion 40 so as to pass through the hook portion 261.

[0071] Next, as shown in FIG. 9, the first cores 5a-5b, the second cores 6a-6b, and the third cores 7a-7b are combined with the bobbin 2 (an assembly of the first bobbin 20 and the second bobbin 24). Next, the first heat dissipation member 10 is attached to the base portion 50, the base portion 60, and the base portion 70. Also, the second heat dissipation members 11a-11b are attached to the second cores 7a and 7b. Next, as shown in FIG. 1, the bobbin 2 and the like are housed in a case 8, and as shown in FIG. 5, resin 9 is filled into the inside of the case 8. In this manner, the coil device 1 can be manufactured.

[0072] As shown in FIG. 1 , in the coil device 1 of this embodiment, the outer legs 51 are spaced apart from the outer legs 61 in the Y-axis direction, which is perpendicular to the axial direction (Z-axis direction) of the bobbin 2 and the direction (X-axis direction) in which the pair of outer legs 51 face each other, so that a gap 12 is formed between the outer legs 51 and 61. Therefore, at least a portion of the cooling air supplied toward the winding portion 40 flows along the outer peripheral surface of the winding portion 40 and flows from the inside to the outside of the first core 5a and the second core 6a through the gap 12 between the outer legs 51 and 61. This cools the winding portion 40, improving the heat dissipation of the coil device 1. Furthermore, there is no need to process the first core 5a and the second core 6a to ensure a flow path for the cooling air, and the heat dissipation of the coil device 1 can be improved with a simple configuration.

[0073] 5, the winding portion 30 has an overlapping portion 32 that overlaps with the winding portion 40 along the radial direction of the winding portion 30, and a non-overlapping portion 33 that does not overlap with the winding portion 40 along the radial direction of the winding portion 30. The non-overlapping portion 33 is disposed inside the resin 9. Therefore, heat from the winding portion 30 is transmitted to the resin 9 through the non-overlapping portion 33, and the winding portion 30 can be cooled effectively.

[0074] Additionally, overlapping portion 32 is exposed from resin 9. Therefore, cooling air supplied toward winding portion 40 is more likely to hit overlapping portion 32, and winding portion 30 can be cooled effectively.

[0075] 1, case 8 has a communication part 82 that connects case 8 in the Y-axis direction from the outer surface to the inner surface of case 8. Therefore, when cooling air flows in the Y-axis direction, the cooling air flows into the inside of case 8 through communication part 82. This makes it easier for the cooling air to hit winding part 40, and winding part 40 can be cooled effectively.

[0076] 6, communication portion 82 is located at a position spaced apart from the surface of resin 9 in a direction toward the opening of case 8. Therefore, the cooling air that flows into the inside of case 8 through communication portion 82 is more likely to hit winding portion 40, and winding portion 40 can be cooled effectively.

[0077] 1, the coil device 1 has a first heat dissipation member 10 having irregularities 100. The first heat dissipation member 10 is disposed directly or indirectly on the base portion 50 and the base portion 60. Therefore, heat from the first core 5a and the second core 6a can be dissipated through the first heat dissipation member 10.

[0078] 6, at least one of the winding section 30 and the winding section 40 has a transformer section 13 that functions as a transformer and an inductor section 14 that functions as an inductor. Therefore, the functions of both a transformer and an inductor are provided in a single coil device 1. This can contribute to the miniaturization of electronic devices compared to when a transformer and an inductor are separately mounted in an electronic device.

[0079] 9, the coil device 1 has a third core 7a adjacent to the first core 5a or the second core 6a (the second core 6a in this embodiment) along the Y-axis direction, and a second heat dissipation member 11a having irregularities 113. The third core 7a is disposed in an inductor section 14, and the second heat dissipation member 11a is disposed directly or indirectly on the end face of the third core 7a in the Y-axis direction. Therefore, heat from the third core 7a, which is less likely to be exposed to cooling air than the first core 5a and the second core 6a, can be dissipated through the second heat dissipation member 11a.

[0080] (Second embodiment) 11 has the same configuration as the coil device 1 of the first embodiment, except for the following points. The same reference numerals are used to designate parts that overlap with the coil device 1 of the first embodiment, and detailed descriptions thereof will be omitted.

[0081] As shown in FIG. 12, the coil device 1A has a bobbin 2A. The bobbin 2A is composed of a single bobbin. The bobbin 2A has a structure in which a protrusion 260 and a hook portion 261 of the second bobbin 24 are added to the first bobbin 20 of the first embodiment. The pair of protrusions 260 protrude from the wall portion 215 and extend in a direction away from the center of the bobbin 2A. The pair of hook portions 261 protrude from the pair of protrusions 260 so as to approach each other.

[0082] 13, the coil device 1A has first cores 5a-5b and second cores 6a-6b, but does not have third cores 7a-7b, unlike the coil device 1 of the first embodiment. The coil device 1A of this embodiment does not have the function of the inductor section 14 (FIG. 6) from the coil device 1 of the first embodiment, and the coil device 1A essentially functions as a transformer.

[0083] 13, in this embodiment as well, the outer leg portion 51 is spaced apart from the outer leg portion 61 in the Y-axis direction so that a gap 12 is formed between the outer leg portion 51 and the outer leg portion 61. Therefore, the same effects as in the first embodiment can be obtained.

[0084] 14, case 8 has a communication part 82 that connects case 8 in the Y-axis direction from the outer surface to the inner surface of case 8. Therefore, when cooling air flows in the Y-axis direction, the cooling air flows into the inside of case 8 through communication part 82. This makes it easier for the cooling air to hit winding part 40, and winding part 40 can be cooled effectively.

[0085] The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the present invention.

[0086] As shown in FIG. 5, in each of the above embodiments, the winding section 40 is stacked on the winding section 30 along the radial direction of the winding section 30. However, the winding section 40 and the winding section 30 may be arranged above and below each other along the winding axis direction of the winding section 30.

[0087] Furthermore, a part of the wound portion 40 (for example, the lower end portion) may be disposed inside the resin 9. [Explanation of symbols]

[0088] 1,1A...Coil device 2,2A...Bobbin 20...1st bobbin 210...Main unit 211,212... Tsuba section 213...Middle flange 214~219…Wall part 220...Protrusion 221...Hook part 222,223… Guide 224...Through hole 24...Second bobbin 250...Main unit 251,252...Flange 253...Middle flange 254~257…Wall part 260...Protrusion 261...Hook part 265...Convex part 3...First wire 30...Winding section 31a, 31b...Drawer part 32...Overlapping section 33...Non-overlapping area 4...Second wire 40...Winding section 41a, 41b...Drawer part 5a, 5b...First core 50...Base 51...Outer leg 52...middle leg 6a, 6b...Second core 60...Base 61...Outer leg 62...middle leg 7a, 7b...Third core 70...Base 71...Outer leg 72...middle leg 8…Case 80...Bottom plate 81a~81d...Side panels 82...Communication part 9...Resin 10...First heat dissipation member 100…Unevenness 11a, 11b... Second heat dissipation member 110...Base 111...Outer leg 112...middle leg 113…Unevenness 12...Gap 13...Transformer section 14...Inductor section

Claims

1. Bobbin and a first winding portion disposed on an outer peripheral surface of the bobbin; a second winding portion disposed directly or indirectly on an outer peripheral surface of the first winding portion; a first core and a second core attached to the bobbin; a case that accommodates at least the bobbin; a resin filled in the case, the first core has a first base portion and a pair of first outer leg portions that protrude from the first base portion and face each other in a first direction perpendicular to the axial direction of the bobbin, the second core has a second base portion and a pair of second outer leg portions that protrude from the second base portion and face each other in the first direction, A coil device in which the first outer leg is spaced from the second outer leg so that a gap is formed between the first outer leg and the second outer leg in a second direction perpendicular to the axial direction and the first direction.

2. the first winding portion has an overlapping portion that overlaps with the second winding portion along a radial direction of the first winding portion, and a non-overlapping portion that does not overlap with the second winding portion along the radial direction of the first winding portion, The coil device according to claim 1 , wherein the non-overlapping portion is disposed inside the resin.

3. The coil device according to claim 2 , wherein the overlapping portion is exposed from the resin.

4. 4. The coil device according to claim 1, wherein the case has a communication portion extending from an outer surface to an inner surface of the case, the communication portion connecting the case in the second direction.

5. The coil device according to claim 4 , wherein the communication portion is located at a position spaced apart from the surface of the resin in a direction toward the opening of the case.

6. The heat dissipation member further includes a first heat dissipation member having an uneven surface, 4. The coil device according to claim 1, wherein the first heat dissipation member is disposed directly or indirectly on the first base and the second base portion.

7. 4. The coil device according to claim 1, wherein at least one of the first winding portion and the second winding portion has a transformer portion that functions as a transformer and an inductor portion that functions as an inductor.

8. a third core adjacent to the first core or the second core along the second direction; a second heat dissipation member having an uneven surface, the third core is disposed in the inductor portion, The coil device according to claim 7 , wherein the second heat dissipation member is disposed directly or indirectly on an end surface of the third core in the second direction.

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