Coil device

Abstract

To provide a coil device excellent in air-cooled heat radiation performance.SOLUTION: A coil device has: a bobbin having an insertion hole along a first direction which is a winding axis direction; first and second winding wires which are wound around the bobbin; and a core which is divided into a plurality of core portions aligned, with a predetermined gap therebetween, along a second direction perpendicular to the first direction. Each of the core portions has a middle leg for inserting the insertion hole so that the core forms a magnetic path surrounding the first and second winding wires on a cross section perpendicular to the second direction. The bobbin has an irregular part formed on a lateral wall outer face which surrounds the insertion hole on a first cross section perpendicular to the first direction, and which faces the first and second winding wires from the inside.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present disclosure relates to a coil device with excellent air-cooled heat dissipation performance. [Background technology]

[0002] For example, in coil devices such as transformers that handle large capacity, heat dissipation efficiency is sometimes required to suppress deformation due to heat and fluctuations in magnetic properties. Also, when there is a need to simplify and downsize equipment that includes coil devices, a coil device that can dissipate heat more effectively with simpler air-cooling methods than with water-cooling methods is required.

[0003] As a coil device that can handle large capacity and takes heat dissipation characteristics into consideration, a coil device has been proposed that uses a core configured by stacking multiple core sections formed by butting together a pair of EE cores (see Patent Document 1, etc.).Also proposed is a coil device that arranges multiple core sections formed by butting together EE cores, with a metal plate disposed between the core sections (see Patent Document 2, etc.). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Utility Model Application Publication No. 58-12915 [Patent Document 2] Japanese Patent Application Laid-Open No. 2011-61096 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in conventional coil devices, there is a problem in that no air flow is formed within the space surrounded by the core where the windings and other components are arranged, making it difficult to achieve efficient air-cooled heat dissipation characteristics. The present disclosure has been made in view of the above circumstances, and provides a coil device having a core configured by arranging a plurality of core portions in a predetermined direction, and having excellent air-cooled heat dissipation performance. [Means for solving the problem]

[0006] In order to achieve the above object, the coil device according to the present disclosure includes: a bobbin having an insertion hole formed along a first direction that is the winding axis direction; first and second windings wound around the bobbin; a core divided into a plurality of core portions arranged at predetermined intervals along a second direction perpendicular to the first direction, each of the core portions having a center leg that passes through the insertion hole, and forming a magnetic path that surrounds the first and second windings in a cross section perpendicular to the second direction; the bobbin has a sidewall outer surface surrounding the insertion hole in a cross section perpendicular to the first direction, the sidewall outer surface facing the first and second windings from the inside, and an uneven portion formed thereon.

[0007] In the coil device according to the present disclosure, the multiple core sections are arranged with a predetermined gap between them, which facilitates airflow between the inside and outside of the core. Also, the bobbin has an outer sidewall with irregularities, which creates gaps between the first and second windings and the bobbin through which airflow for cooling can enter, resulting in a coil device with excellent air-cooling heat dissipation performance.

[0008] Further, for example, the uneven portion may have a pair of side wall base surfaces extending along the second direction on either side of the insertion hole, and a plurality of ribs protruding from the side wall base surfaces in a third direction perpendicular to the first and second directions.

[0009] The uneven portion formed on the outer surface of the side wall can be formed by holes or the like, but by having the uneven portion have a side wall base surface and ribs protruding from it, it is possible to suitably ensure the strength of the bobbin.

[0010] Furthermore, for example, the plurality of ribs may include a first rib arranged in a central portion of the bobbin in the second direction, and a second rib arranged between the first rib and an end portion of the bobbin in the second direction, The first rib may protrude to a greater height in the third direction than the second rib.

[0011] By changing the height of the ribs of the concave and convex portions in this way, the first and second windings and their surrounding areas can be effectively cooled by a cooling airflow along the second direction, for example.

[0012] Furthermore, for example, the bobbin may have a flange portion that protrudes from the outer surface of the side wall in a direction perpendicular to the first direction and divides the first and second windings into a portion on one side and a portion on the other side in the first direction, A stepped surface may be formed on at least one of a central flange upper surface and a central flange lower surface of a portion of the flange that is disposed in the center of the bobbin in the second direction.

[0013] A coil device having such a flange portion can effectively cool the first and second windings and their surrounding areas with cooling airflow by forming a larger gap between the first and second windings and the flange portion.

[0014] Furthermore, for example, the bobbin has a flange portion that protrudes from the outer surface of the side wall in a direction perpendicular to the first direction and divides the first and second windings into a portion on one side and a portion on the other side in the first direction, The flange portion may be discontinuously formed along the outer surface of the side wall with four or more notches sandwiched therebetween in a cross section perpendicular to the first direction.

[0015] Since the flange portion is formed discontinuously with four or more notches in between, it is possible to avoid the problem of the flange portion obstructing the flow of cooling air, and such a coil device exhibits good air-cooled heat dissipation performance.

[0016] Also, for example, the coil winding is disposed on a lower side, which is one side in the first direction, with respect to the bobbin, the first and second windings, and the core, The motor may have a metal base on which the bobbin, the first and second windings, and the core are mounted.

[0017] By having a metal base with high thermal conductivity, such a coil device exhibits good air-cooling heat dissipation performance.

[0018] Also, for example, the motor may have a metal block that is connected to the metal base at at least two points and that, together with the metal base, forms a heat conduction path that surrounds the first and second windings in a cross section perpendicular to the second direction.

[0019] In such a coil device, the metal block can efficiently transfer heat generated around the first and second windings to the metal base via the metal block, thereby dissipating the heat.

[0020] Furthermore, for example, the core portion may be fixed to the metal base via heat dissipation grease.

[0021] In such a coil device, heat from the core portion is easily transferred to the metal base via the heat dissipation grease, thereby achieving good air-cooled heat dissipation performance.

[0022] Furthermore, for example, the side wall outer surface may include a pair of side wall base surfaces extending along the second direction with the insertion hole therebetween, and a pair of side wall end surfaces connecting end portions of the pair of side wall base surfaces in the second direction, At least one of the pair of side wall end surfaces may have a through hole formed therein that communicates with the insertion hole.

[0023] In such a coil device, the cooling air current along the second direction can easily pass through the inside of the insertion hole, so that the bobbin and the periphery of the first and second windings wound around the bobbin can be effectively cooled.

[0024] Furthermore, for example, the coil device may have a metal heat sink that is arranged on the upper side, that is, the other side of the first direction, relative to the bobbin, the first and second windings, and the core, and that has a connecting lower surface that is connected to the multiple core parts that make up the core and faces downward, that is, one side of the first direction, and a heat dissipating upper surface that faces upward, that is, the other side of the first direction, and on which a heat dissipating uneven portion is formed.

[0025] Such a heat sink can effectively dissipate heat from the core, and therefore exhibits excellent air-cooling heat dissipation performance.

[0026] Also, for example, the motor may have a metal case that is connected to the metal base at at least two points and that, together with the metal base, forms an accommodation space for accommodating the bobbin, the first and second windings, and the core.

[0027] Such a coil device can effectively prevent local temperature rises in areas far from the metal base by conducting heat from the upper portion far from the metal base to the metal base via the case. [Brief explanation of the drawings]

[0028] [Figure 1] FIG. 1 is an external view of a coil device according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is an external view showing the coil device shown in FIG. 1 with the case removed. [Figure 3] 3 is a front view showing the coil body of the coil device shown in FIG. [Figure 4] 4 is a left side view of the coil body shown in FIG. 3. FIG. [Figure 5] FIG. 5 is a perspective view showing a state in which a heat sink is removed from the coil body shown in FIG. [Figure 6] FIG. 6 is a conceptual diagram showing a state in which a part of the core is further removed from the coil body shown in FIG. [Figure 7]FIG. 7 is a conceptual diagram showing a state in which the entire core and the first winding have been removed from the coil body shown in FIG. [Figure 8] FIG. 8 is a front view showing the coil body shown in FIG. 5 with the entire core and the first winding removed. [Figure 9] FIG. 9 is a left side view showing the coil body shown in FIG. 5 with the entire core and the first winding removed. [Figure 10] FIG. 10 is a partially enlarged view of the coil body shown in FIG. 5, from which the entire core and the first winding have been removed, as viewed obliquely from below. [Figure 11] FIG. 11 is a cross-sectional view of the coil body, excluding the core and the first winding, as viewed from above. [Figure 12] FIG. 12 is a partial assembly view showing the metal base and metal block in the coil device. DETAILED DESCRIPTION OF THE INVENTION

[0029] Hereinafter, the present disclosure will be described based on embodiments shown in the drawings.

[0030] Fig. 1 is an external view of a coil device 10 according to the present disclosure. A case 90 is attached to a coil main body 16 (see Fig. 2) of the coil device 10, and the bobbin 20 and other components included in the coil main body 16 are housed in a housing space 90a (see Fig. 2) formed by the case 90 and a metal base 72, etc. As shown in Fig. 1, ends of a first winding 40 and a second winding 50 are drawn out to the outside of the case 90.

[0031] 1 is used as a transformer or the like with a relatively large capacity, but the use of the coil device 10 is not limited to only transformers. Furthermore, the coil device 10 is preferably used as an air-cooled coil device that is cooled by a gas (air) flow around the coil device 10, rather than a water-cooled coil device. It is also preferable to form a cooling airflow along the second direction D2 around the coil device 10 using an air-cooling device such as a fan.

[0032] 2 is an external view showing the coil device 10 shown in FIG. 1 with the case 90 separated from the coil main body 16. The case 90 can be removed from the metal base 72 and separated from the coil main body 16 by loosening fixing screws or the like. In the description of the coil device 10, the parts other than the case 90 will be referred to as the coil main body 16.

[0033] 2, the coil device 10 includes a bobbin 20, first and second windings 40 and 50 wound around the bobbin 20, and a core 60. The coil device 10 also includes a metal base 72, a metal block 74, a heat sink 80, and a case 90.

[0034] Fig. 3 is a front view of the coil main body 16 in the coil device 10 shown in Fig. 2, as viewed from a third direction D3, and Fig. 4 is a side view of the coil main body 16 as viewed from a second direction D2. Also, Fig. 5 is a perspective view of the coil main body 16 in the coil device shown in Fig. 2, as viewed obliquely from above.

[0035] 3 to 5, a core 60 is attached to the bobbin 20, and in FIGS. 3 to 5, the central portion of the bobbin 20 in the second direction D2 is hidden by the core 60. FIG. 6 is a partial exploded view of the coil main body 16 shown in FIG. 5, showing an upper core 63 of each core portion 62 included in the core 60 and a portion of the first winding 40 wound around the upper portion of the bobbin 20. As shown in FIG. 6, the bobbin 20 has an insertion hole 22 formed therein that is aligned with the first direction D1, which is the winding axis direction of the first and second windings 40, 50.

[0036] 6 or 11, the bobbin 20 has a generally elliptical cylindrical outer shape with the major axis of the ellipse extended along a second direction D2 perpendicular to a first direction D1, which is the penetration direction of the insertion hole 22. As shown in FIGS. 3 and 4, a first winding 40 and a second winding 50 are wound around the outer surface 23 of the side wall of the bobbin 20 (see FIG. 7). The bobbin 20 has a plurality of flanges 32. The detailed structure of the bobbin 20 will be described later.

[0037] 3 and 5, the core 60 is divided into a plurality of core portions 62 arranged at predetermined intervals along the second direction D2. In the embodiment, the core 60 has seven core portions 62, but the number of core portions 62 included in the core 60 is not limited to seven.

[0038] The core 60 is divided into multiple core portions 62, which prevents damage to the core 60 due to localized stress concentrations caused by thermal expansion and the like. As shown in Fig. 3, it is preferable that the core portions 62 are arranged with gaps smaller than the width of the core portions 62, as this prevents stress from being transmitted between the core portions 62. Furthermore, the gaps formed between the core portions 62 facilitate the formation of airflow that contributes to heat dissipation around the first winding 40 and the second winding 50 wound around the bobbin 20, resulting in good air-cooled heat dissipation characteristics.

[0039] As can be seen from Figures 4 and 5, the core portion 62 is composed of an upper core 63 and a lower core 64 that face each other along the first direction D1. Both the upper core 63 and the lower core 64 have an E-shaped external shape, and the core portion 62 is a so-called EE core. However, the core portion 62 included in the core 60 is not limited to a so-called EE core, and the core portion 62 may have other shapes, such as a so-called EI core. Furthermore, the core 60 may include core portions with different shapes.

[0040] 4 and 5, the upper core 63 and the lower core 64 have center legs 63a, 64a extending along the first direction D1 and side legs 63b, 64b and side legs 63c, 64c arranged on either side of the center legs 63a, 64a. The upper core 63 also has a connecting portion 63d connecting the upper ends of the center legs 63a, 63b, and 63c along a third direction perpendicular to the first direction D1 and the second direction D2. The lower core 65 also has a connecting portion 64d connecting the lower ends of the center legs 64a, 64b, and 64c along the third direction D3.

[0041] 4, each core portion 62 has center legs 63a, 64a that are inserted into the insertion hole 22 of the bobbin 20. Each core portion 62 forms a magnetic path 67 that surrounds the first and second windings 40, 50 in a cross section perpendicular to the second direction D2, by means of the center legs 63a, 64a, side legs 63b, 64b, 63c, 64c, and connecting portions 63d, 64d. The material of the core 60 is not particularly limited, but examples include magnetic materials such as ferrite and iron.

[0042] 6, the coil device 10 according to the present disclosure will be described with the winding axis direction of the first and second windings 40, 50 relative to the bobbin 20 as a first direction D1, the arrangement direction of the core portions 62 perpendicular to the first direction D1 as a second direction D2, and the direction perpendicular to the first direction D1 and the second direction D2 as a third direction D3. In addition, in the first direction D1, the direction from the center of the coil device 10 toward the connection portion 64d of the lower core 64 will be described as a downward direction, and the direction from the center of the coil device 10 toward the connection portion 63d of the upper core 63 will be described as an upward direction. However, the installation posture of the coil device 10 is not limited to the orientation in which the metal base 72 is downward as shown in FIG. 1, and may be an installation posture different from the installation posture shown in FIG. 1.

[0043] 3, 4, and 6, the first winding 40 is wound around the upper portion of the bobbin 20, and the second winding 50 is wound around the lower portion of the bobbin 20. However, the arrangement of the first and second windings 40, 50 wound around the coil device 10 is not limited to the arrangement in which the first winding 40 and the second winding 50 are separated in the vertical direction as shown in FIGS. 3 and 4. For example, a modified example in which the first winding 40 and the second winding 50 are wound around the bobbin 20 so as to overlap in the first direction D1 is also conceivable. The first winding 40 and the second winding 50 are formed, for example, by winding a coated conductor wire around the outer surface 23 of the side wall of the bobbin 20.

[0044] 5 and 6, the metal base 72 is disposed below the bobbin 20, the first and second windings 40, 50, and the core 60, on one side in the first direction D1. The bobbin 20, the first and second windings 40, 50, the core 60, and the heat sink 80 (see FIG. 2) are placed on the metal base 72.

[0045] 12 is a perspective view showing the metal base 72 and the metal block 74 connected to the metal base 72. The metal base 72 has a substantially rectangular flat plate shape when viewed from the first direction D1, and is made of a metal material with high thermal conductivity, such as aluminum, iron, or an alloy containing aluminum or iron.

[0046] 6 and 12, the length of the metal base 72 along the second direction D2 is longer than the length of the bobbin 20 along the second direction D2, and the length of the metal base 72 along the third direction D3 is longer than the length of the core 60 along the third direction D3. As shown in FIG. 10, when the coil device 10 is viewed from above in the first direction D1, the bobbin 20 and the core 60 are preferably disposed inside the outer edge of the metal base 72. By disposing them in this manner, heat generated around the first winding 40 and the second winding 50 and in the core 60 can be effectively dissipated via the metal base 72.

[0047] 6, the core 60 is fixed to the metal base 72 via heat dissipation grease 76. That is, in the coil device 10, the opposing surfaces of the upper core 63 and the lower core 64 are fixed with the heat dissipation grease 76, and further, the opposing surface of the connection part 64d of the lower core 64 and the metal base 72 is fixed with the same heat dissipation grease 76. As a result, heat generated inside the coil device 10 can be transferred to the metal base 72 via the core 60 and effectively dissipated to the outside via the metal base 72.

[0048] As shown in Fig. 12, the coil device 10 has a metal block 74 provided so as to protrude upward from a metal base 72. The metal block 74 is connected to the metal base 72 at least at two lower connection portions 74a. The metal block 74 also has an upper insertion portion 74b, at least a portion of which is located within the insertion hole 22 of the bobbin 20. As shown in Fig. 3, the metal block 74 is disposed adjacent to the core portion 62 that is closest to the lead-out portions 40a, 50a of the first and second windings 40, 50, among the core portions 62 arranged in the second direction D2.

[0049] FIG. 9 is a left side view of the coil main body 16 excluding the core 60 and the first winding 40. As shown in FIG. 9, the metal block 74, together with the metal base 72, forms a heat conduction path 74d surrounding the first and second windings 40, 50 in a cross section perpendicular to the second direction D2. Like the metal base 72, the metal block 74 may be made of a metal material such as aluminum. Also, as shown in FIG. 9, the metal block 74 may be fixed to the end face of the core 60 on the second direction D2 side via heat dissipation grease 76. Furthermore, the upper end of the metal block 74 may be connected to the lower surface of the top wall 91 of the case 90 via the heat dissipation grease 76.

[0050] The metal block 74 efficiently transfers heat around the upper core 63 and the first winding 40, which are far from the metal base 72, to the metal base 72, thereby effectively dissipating heat generated inside the coil device 10 to the outside. It is also preferable to arrange the metal block 74 adjacent to the core 60 so that it is connected to the end of the core 60 in the second direction D2 that is downstream of the cooling airflow. By arranging it in this way, it is possible to improve heat dissipation on the downstream side of the cooling airflow in the core 60, where heat tends to escape less easily.

[0051] As shown in Fig. 2, the coil device 10 has a metallic heat sink 80 disposed above the bobbin 20, the first and second windings 40, 50, and the core 60, on the other side in the first direction D1. As shown in Fig. 3, the heat sink 80 has a lower connection surface 80b and a heat-dissipating upper surface 80a. The lower connection surface 80b faces downward, on one side in the first direction D1, and connects to the connection portion 63d of the upper core 63 in the core portion 62 that constitutes the core 60. The lower connection surface 80b and the core 60 are fixed together via heat-dissipating grease 76 (see Fig. 6).

[0052] The heat-dissipating upper surface 80a of the heat sink 80 faces upward, which is the other side of the first direction D1, and is formed with heat-dissipating irregularities 82. The heat sink 80 can efficiently dissipate heat around the upper core 63 and the first winding 40, which are far from the metal base 72. In the coil device 10, the heat sink 80 and the metal block 74 are arranged to sandwich the core 60 from above and below, making it possible to effectively dissipate heat generated inside the coil device 10 to the outside.

[0053] 1 and 2, the case 90 of the coil device 10, together with the metal base 72, forms an accommodation space 90a that accommodates the bobbin 20, the first and second windings 40, 50, and the core 60. As shown in Fig. 2, the case 90 is connected to the metal base 72 at least at two locations on both sides in the third direction D3.

[0054] The case 90 has a top wall 91, case side walls 92, and end walls 93. An opening is formed in the top wall 91 of the case 90 to expose the heat dissipation irregularities 82 of the heat sink 80. Furthermore, a through hole is formed in the end wall 93 of the case 90 so that a cooling flow can pass through the end wall 93 and enter the accommodation space 90a. As with the metal base 72 and the metal block 74, the heat sink 80 and the case 90 may be made of a metal material such as aluminum.

[0055] 7 is a conceptual diagram showing the coil main body 16 shown in FIG. 5 with the entire core 60 and the first winding 30 removed. As shown in the upper portion of the bobbin 20 where the first winding 30 is disposed, an uneven portion 24 is formed on the sidewall outer surface 23 of the bobbin 30 that faces the first and second windings 40, 50 from the inside. The sidewall outer surface 23 is a surface that surrounds the insertion hole 22 in a cross section (see FIG. 10) perpendicular to the first direction D1.

[0056] Fig. 8 is a front view of the bobbin 20 etc. in the state shown in Fig. 7 as viewed from the third direction D3, and Fig. 9 is a side view of the bobbin 20 etc. in the state shown in Fig. 7 as viewed from the second direction D2. Fig. 10 is a partially enlarged view of the bobbin 20 etc. in the state shown in Fig. 7 as viewed from diagonally below. As shown in Figs. 7 to 10 (particularly Fig. 10), the uneven portion 24 formed on the side wall outer surface 23 has a side wall base surface 25 and a plurality of ribs 26 protruding from the side wall base surface 25.

[0057] Fig. 11 is a cross-sectional view of the bobbin 20 shown in Fig. 7 taken along a cross section perpendicular to the first direction D1. As shown in Fig. 11, the uneven portion 24 formed on the sidewall outer surface 23 surrounding the insertion hole 22 has a pair of sidewall base surfaces 25 extending in the second direction D2 with the insertion hole 22 sandwiched therebetween. The pair of sidewall base surfaces 25 are arranged spaced apart from each other in a third direction D3 perpendicular to the first direction D1 and the second direction D2. As can be seen from Fig. 5, parts of the center legs 63a, 64a of the core portion 62 are arranged between the pair of sidewall base surfaces 25.

[0058] 11, the uneven portion 24 has a plurality of ribs 26 protruding in the third direction D3 from the side wall base surface 25, and the uneven portion 24 is formed by the side wall base surface 25 and the ribs 26. The plurality of ribs 26 includes a first rib 26a, a second rib 26b, and a third rib 26c.

[0059] 10, the first rib 26a, the second rib 26b, and the third rib 26c included in the plurality of ribs 26 all extend along the first direction D1. Ribs extending along the second direction D2 are also formed on the sidewall outer surface 23, and the ribs extending along the second direction D2 reinforce the plurality of ribs 26 extending along the first direction D1. However, the ribs extending along the second direction D2 do not necessarily have to be formed on the sidewall outer surface 23.

[0060] 11, the first rib 26a is disposed in the center of the bobbin 20 in the second direction D2. The second rib 26b is disposed between the first rib 26a and the end of the bobbin 20 at which the sidewall end surface 27 is disposed in the second direction D2. The protruding height of the first rib 26a in the third direction D3 is higher than the protruding height of the second rib 26b in the third direction D3. The third rib 26c is disposed between the first rib 26a and the second rib 26b in the second direction D2, and its protruding height in the third direction D3 is lower than that of the first rib 26a and higher than that of the second rib 26b.

[0061] 10, it is hidden inside the second winding 50, but the lower portion of the side wall outer surface 23 of the bobbin 20 also has an uneven portion 24 similar to the upper portion. As shown in Figures 7, 8, 10, and 11, the uneven portion 24 formed on the side wall outer surface 23 of the bobbin 20 reduces the contact area between the first and second windings 40, 50 and the side wall outer surface 23, making it easier for the airflow that cools the coil device 10 to hit a wider area of ​​the first and second windings 40, 50, and promoting heat dissipation from the first and second windings 40, 50.

[0062] 10 and 11, the uneven portion 24 is composed of a plurality of ribs 26 and the side wall base surface 25, which makes it possible to form a large gap between the first and second windings 40, 50 and the side wall base surface 25, thereby enabling effective air cooling of the first and second windings 40, 50. Furthermore, as shown in Fig. 11, by making the height of the first rib 26a in the center of the bobbin 20 higher than the height of the second rib 26b near the ends, the first and second windings 40, 50 are inclined with respect to the second direction D2, which enables effective cooling by the cooling airflow along the second direction D2.

[0063] 11, the side wall outer surface 23 has a pair of side wall base surfaces 25 extending in the second direction D2 with the insertion hole 22 therebetween, and a pair of side wall end surfaces 27 connecting adjacent ends in the second direction D2 of the pair of side wall base surfaces 25. Each side wall end surface 27 has a substantially semicircular shape in a cross section perpendicular to the first direction.

[0064] 9, at least one of the pair of side wall end faces 27 (the side wall end face 27 shown in FIG. 9 is the side wall end face 27 opposite the lead-out portions 40a, 50a of the first and second windings 40, 50) has a through hole 27a that communicates with the insertion hole 22 of the bobbin 20 from the outside of the side wall end face 27. The through hole 27a is formed to straddle the end flange portion 36 in the vertical direction with respect to the first direction D1.

[0065] By forming the through holes 27a in the side wall end surface 27, the airflow that cools the coil device 10 can be easily introduced into the insertion hole 22, thereby improving the heat dissipation efficiency particularly in the central portion of the coil device 10. Note that, as shown in Fig. 9, it is also preferable that a plurality of through holes 27a are formed intermittently in the side wall end surface 27 along the first direction D1.

[0066] As shown in Figures 7, 8, and 10, the bobbin 20 has a flange 32 that protrudes outward from the sidewall outer surface 23 in a direction perpendicular to the first direction D1. The bobbin 20 has multiple flanges 32 at different positions in the first direction D1. Each flange 32 divides the first and second windings 40, 50 into a portion on one side (lower side) and a portion on the other side (upper side) in the first direction D1. The flanges 32 prevent misalignment of the turns constituting the first and second windings 40, 50 in the height direction and also form gaps above and below each turn.

[0067] 7 and 9, the flange portion 32 includes a central flange portion 34 disposed in the center of the bobbin 20 in the second direction D2, and end flange portions 36 disposed at the ends of the bobbin in the second direction D2. A stepped surface is formed on at least one (in this embodiment, both) of a central flange upper surface 34a (see FIG. 7) and a central flange lower surface 34b (see FIG. 10) of the central flange portion 34 of the flange portion 32.

[0068] The step surfaces formed on the central flange upper surface 34a and the central flange lower surface 34b can reduce the contact area of ​​the first and second windings 40, 50 with the central flange 34. Furthermore, the upper and lower step surfaces make it easier for each turn of the first and second windings 40, 50 to be positioned more centrally between the upper and lower flanges 32 in the first direction D1. In the bobbin 20, these step surfaces can reduce the contact area of ​​the first and second windings 40, 50 with the flange 32, thereby increasing the area of ​​the surfaces of the first and second windings 40, 50 that can come into contact with the cooling flow.

[0069] 11, the flange 32 is discontinuously formed along the sidewall outer surface 23, sandwiching four or more (four in the embodiment) notches 38 in a cross section perpendicular to the first direction D1. That is, the notches 38 are formed between the central flange 34 and the end flange 36. In this way, by discontinuously forming the flange 32 with four or more notches 38 in between, it is possible to increase the gaps formed above and below each turn of the first and second windings 40, 50, enabling efficient air cooling by cooling airflow. Note that the bobbin 20 may be made of an insulating resin.

[0070] While the coil device 10 according to the present disclosure has been described above using an embodiment, it goes without saying that the technical scope of the present disclosure is not limited to the embodiment shown as the coil device 10, but also includes other embodiments and modifications. For example, the uneven portion 24 formed on the side wall outer surface 23 of the bobbin 20 may be configured by holes formed on the side wall base surface 25, or by protrusions other than ribs.

[0071] The coil device 10 may also include a fan that generates a cooling airflow along the second direction D2 for the bobbin 20, the first and second windings 40, 50, and the core 60. By forming an airflow along the second direction D2 around the bobbin 20, an airflow that flows along the second direction D2 is formed in the gaps formed above and below the first and second windings 40, 50, and the coil device 10 exhibits favorable heat dissipation characteristics. [Explanation of symbols]

[0072] 10...Coil device 16...Coil body 20...Bobbin 22...Through hole 23...Side wall outer surface 24...Uneven part 25...Side wall base 26...Rib 26a...1st Rib 26b...2nd rib 26c...3rd rib 27...Side wall end surface 27a...Through hole 32...Flange 34...Central flange 34a...Top of central tsuba 34b...Central tsuba lower surface 36...End flange 38...Notch 40...1st winding 50...Second winding 40a, 50a...Drawer part 60...Core 62...Core part 63...Upper core 64...Lower core 63a, 64a...middle leg 63b, 64b, 63c, 64c...side leg 63d, 64d...Connection 67...magnetic path 72...Metal base 74...Metal block 74a...Lower connection part 74b...Upper insertion part 76...Thermal grease 80...heat sink 80a…Heat radiation top surface 80b…Connection bottom surface 82...Heat dissipation uneven part 90…case 90a...Containment space 91...Ceiling wall 92…Case side wall 93...End wall D1…first direction D3…Third direction D2…Second direction

Claims

1. a bobbin having an insertion hole formed along a first direction that is a winding axis direction; first and second windings wound around the bobbin; a core divided into a plurality of core portions arranged at predetermined intervals along a second direction perpendicular to the first direction, each of the core portions having a center leg that passes through the insertion hole, and forming a magnetic path that surrounds the first and second windings in a cross section perpendicular to the second direction; The bobbin has a side wall outer surface that surrounds the insertion hole in a cross section perpendicular to the first direction and faces the first and second windings from the inside, and has an uneven portion formed on the outer surface.

2. The coil device according to claim 1, wherein the uneven portion has a pair of side wall base surfaces extending along the second direction on either side of the insertion hole, and a plurality of ribs protruding from the side wall base surfaces in a third direction perpendicular to the first and second directions.

3. the plurality of ribs include a first rib disposed in a central portion of the bobbin in the second direction and a second rib disposed between the first rib and an end portion of the bobbin in the second direction; The coil device according to claim 2 , wherein a protruding height of the first rib in the third direction is greater than a protruding height of the second rib in the third direction.

4. the bobbin has a flange portion that protrudes from the outer surface of the side wall in a direction perpendicular to the first direction and divides the first and second windings into a portion on one side and a portion on the other side in the first direction, The coil device according to claim 1 , wherein a stepped surface is formed on at least one of a central flange upper surface and a central flange lower surface of the flange portion that is located in the center of the bobbin in the second direction.

5. the bobbin has a flange portion that protrudes from the outer surface of the side wall in a direction perpendicular to the first direction and divides the first and second windings into a portion on one side and a portion on the other side in the first direction, The coil device according to claim 1 , wherein the flange portion is discontinuously formed along the outer surface of the side wall with four or more notches sandwiched therebetween in a cross section perpendicular to the first direction.

6. the bobbin, the first and second windings, and the core are disposed on one side in the first direction, below the bobbin, the first and second windings, and the core; 2. The coil device according to claim 1, further comprising a metal base on which the bobbin, the first and second windings, and the core are mounted.

7. 2. The coil device according to claim 1, further comprising a metal block connected to the metal base at at least two locations and forming, together with the metal base, a heat conduction path surrounding the first and second windings in a cross section perpendicular to the second direction.

8. The coil device according to claim 7 , wherein the core portion is fixed to the metal base via heat dissipation grease.

9. the side wall outer surface includes a pair of side wall base surfaces extending in the second direction with the insertion hole therebetween, and a pair of side wall end surfaces connecting end portions of the pair of side wall base surfaces in the second direction, The coil device according to claim 1 , wherein a through hole communicating with the insertion hole is formed in at least one of the pair of side wall end surfaces.

10. 2. The coil device according to claim 1, further comprising a metal heat sink arranged on the upper side of the bobbin, the first and second windings, and the core, the lower surface being connected to the core portions constituting the core and facing downward on one side of the first direction, and a heat dissipation upper surface facing upward on the other side of the first direction and having a heat dissipation irregularity formed thereon.

11. 8. The coil device according to claim 7, further comprising a metal case connected to the metal base at at least two locations and forming, together with the metal base, an accommodation space for accommodating the bobbin, the first and second windings, and the core.

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