JP2018160542A - Coil device - Google Patents

Abstract

An object of the present invention is to provide a coil device capable of coping with an increase in current of the coil device by improving heat dissipation. A coil device having a magnetic core, a bobbin, and a coil mounted on the bobbin, wherein the coil device is disposed between two bobbin bottoms and two bobbin bottoms. And a heat radiating member disposed to face the core bottom of the magnetic core 40. The bobbin bottom 21 has an uneven shape that forms a heat radiation path between the bobbin bottom 21 and the heat radiation path. The heat radiation path is continuous from the outer side surface of the bobbin bottom 21 to the core bottom. [Selection diagram] FIG.

Description

  The present invention relates to a coil device that can be suitably used as a switching power supply such as an AC-DC power supply, for example, a noise filter used for an AC-DC power supply for charging an in-vehicle battery, for example.

  For example, the following Patent Document 1 is known as a transformer used for charging an EV battery. Thus, a high current is applied to a transformer used in a vehicle or the like, and a countermeasure for heat dissipation is required.

  Conventionally proposed coil devices include a bobbin, a magnetic core, and a heat radiating member connected to the bobbin installation part or the core installation part so that heat can be transferred to the inside of the bobbin around which the heat generating coil is wound or the magnetic core. The heat accumulated in the bobbin installation part and the core installation part can be transmitted well from the bobbin and the magnetic core to the heat dissipation member, and the heat can be dissipated from the heat dissipation member.

JP-A-2006-139699

  Coil devices such as a natural cooling system may be used for cooling a noise filter used in an AC-DC power supply for charging an in-vehicle battery, instead of a water cooling system used for cooling an in-vehicle transformer. There are differences in the cooling system employed depending on the application. Accordingly, there is a demand for a coil device that can further improve the heat dissipation characteristics as compared with the conventional coil device that can cope with such applications.

  This invention is made | formed in view of such an actual condition, The objective is to provide the coil apparatus which can respond to the increase in current of a coil apparatus by improving heat dissipation.

In order to achieve the above object, a coil device according to the present invention comprises:
A coil device having a magnetic core, a bobbin, and a coil attached to the bobbin,
A heat dissipating member disposed to face the two bobbin bottoms of the bobbin and the core bottom of the magnetic core disposed between the two bobbin bottoms;
The bobbin bottom is formed with a concavo-convex shape that forms a heat dissipation path with the heat dissipation member,
The heat dissipation path is continuous from the outer side surface of the bobbin bottom to the core bottom.

  In the coil device of the present invention in which the uneven shape forming the heat radiation path is formed at the bottom of the bobbin, the heat radiation characteristic from the bobbin is greatly improved. In other words, the formation of the uneven shape increases the contact area with the heat dissipation path and improves the heat dissipation characteristics. Moreover, since the thickness of the resin constituting the bottom of the bobbin can be reduced by forming the concavo-convex shape, the heat dissipation characteristics are improved as compared with the conventional bobbin. For example, when a resin containing a filler that improves heat conduction is adopted as the resin constituting the bobbin, the orientation of the filler may cause a problem that the thermal conductivity in the thickness direction is not sufficiently improved. Such a problem can be prevented in the coil device of the present invention in which the thickness of the bobbin bottom is thin.

  Furthermore, the heat dissipation path is continuous from the outer side surface of the bobbin to the core bottom, so that the heat around the core bottom is dissipated through the heat dissipation path, resulting in heat dissipation characteristics from the magnetic core and coil near the core bottom. Will improve. Moreover, not only heat dissipation via the heat dissipation member but also heat dissipation from the outer side surface of the bobbin is improved, so that heat can be dissipated not only from the water cooling system that releases heat intensively from the heat dissipation member but also from parts other than the heat dissipation member. Even when the required natural cooling system is employed, the coil device of the present invention exhibits good heat dissipation characteristics.

  For example, at least a part of the heat dissipation path may be filled with potting resin.

  When the heat dissipation path is filled with a resin having a higher thermal conductivity than air, in such a coil device, heat exchange between the bottom portion of the bobbin and the heat dissipation member is particularly efficient through the potting resin. In addition, it is considered that a system that dissipates the heat at the bottom of the core from the outer side surface of the bobbin via the heat dissipation path becomes more efficient via the potting resin. Therefore, such a coil device exhibits good heat dissipation characteristics.

  For example, the uneven shape may have a fin-like protrusion that continues from the inner side surface of the bobbin bottom portion toward the outer side surface and protrudes toward the heat radiating member.

  The uneven shape has fin-like projections to improve the heat dissipation characteristics by forming a heat dissipation path, and also from the bobbin itself to perform heat dissipation utilizing high thermal conductivity in the direction perpendicular to the thickness direction. it can. Therefore, such a coil device exhibits good heat dissipation characteristics.

  Further, for example, the uneven shape may have a plurality of columnar protrusions that are provided intermittently from the inner side surface of the bobbin bottom to the outer side surface and project toward the heat radiating member.

  Since the uneven shape has a plurality of columnar protrusions, a heat dissipation path can be formed to improve heat dissipation characteristics, the surface area of the bobbin bottom can be effectively expanded, and the contact area between the bobbin bottom and the heat dissipation path can be expanded. . Therefore, such a coil device exhibits good heat dissipation characteristics.

In addition, for example, the heat dissipation path includes a first heat dissipation path provided between one of the two bobbin bottoms and the heat dissipation member, the other bobbin bottom of the two bobbin bottoms, and the A second heat radiation path provided between the heat radiation members may be provided, and the potting resin may connect the first heat radiation path and the second heat radiation path.

  By connecting the first heat dissipation path and the second heat dissipation path with the potting resin, it is possible to effectively prevent a problem that a portion where heat is locally accumulated in a part of the coil device is generated. In addition, the potting resin that connects the first heat dissipation path and the second heat dissipation path comes into contact with the bottom of the core, so that such a coil device can also efficiently dissipate the magnetic core.

FIG. 1 is a perspective view of a coil device according to an embodiment of the present invention. FIG. 2 is an exploded perspective view of the coil device shown in FIG. FIG. 3 is a perspective view showing a bobbin bottom and a core bottom in the coil device shown in FIG. 1. FIG. 4 is a cross-sectional view illustrating the heat dissipation path and the potting resin that satisfies the heat dissipation path in the coil device illustrated in FIG. 1. 5 is a cross-sectional perspective view of the coil device taken along a line VV shown in FIG. 1 and perpendicular to the mounting surface. 6 is a cross-sectional perspective view of the coil device taken along a line VI-VI shown in FIG. 1 and perpendicular to the mounting surface. FIG. 7 is a cross-sectional view of a coil device according to another embodiment of the present invention, and is a cross-sectional view corresponding to FIG.

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

First Embodiment As shown in FIGS. 1 and 2, a coil device 10 according to the present embodiment is used in an AC-DC power supply for charging an in-vehicle battery, for example, as a noise filter or the like. However, the use of the coil device 10 is not limited to this, and may be used as a vehicle-mounted transformer for charging a PHV or EV battery. As shown in FIG. 2, the coil device 10 includes a bobbin 20, a magnetic core 40, and a heat radiating plate 80. Although not shown in FIG. 2, the coil device 10 includes a first wire 37 and a second wire 38 constituting the coil, and a potting resin 90 as shown in FIGS. 5 and 6 which are cross-sectional views. Have. In FIG. 2, the first wire 37, the second wire 38, and the potting resin 90 in the coil device 10 are not shown.

  As shown in FIG. 2, the bobbin 20 is connected to the winding tube portion 26 and above the winding tube portion 26 (on the Z-axis positive direction side) and is integrated with the winding tube portion 26. 29, a lead wire installation portion 22, and an end partition wall 28 and a bobbin bottom portion 21 which are connected to the lower side of the winding tube portion 26 and are integrated with the winding tube portion 26. Above the bobbin 20, two lead wire installation portions 22 provided at both ends in the X-axis direction are provided, and below the bobbin 20, two bobbin bottoms 21 are provided at both ends in the X-axis direction. In the lead wire installation part 22, a lead part of the first wire 37 and a lead part of the second wire 38, which will be described later, are installed. Further, the lead portions of the first wire 37 and the second wire 38 installed in the lead wire installation portion 22 are covered by a lead wire insulating cover 54 provided in the bobbin 20.

  As shown in FIG. 2, in the present embodiment, the magnetic core 40 includes an upper core 40a and a lower core 40b. The upper core 40a and the lower core 40b can be separated into two divided cores 42a, 42a and 42b, 42b having the same shape. In the present embodiment, each of the divided cores 42a, 42a and 42b, 42b has the same shape, has a U-shaped cross section in the ZY section, and is a kind of U-shaped core.

  By combining a pair of split cores 42a and 42a arranged at the upper part in the Z-axis direction, the Z-Y cross section has an E-shaped cross section, and constitutes a so-called E-type upper core 40a. The other pair of split cores 42b and 42b arranged at the lower part in the Z-axis direction are also combined to form a lower core 40b which is a so-called E-shaped core having an E-shaped cross section in the ZY cross section. .

  Each split core 42a disposed on the upper side in the Z-axis direction includes an upper base portion 44a extending in the Y-axis direction, and a pair of middle leg portions 46a protruding in the Z-axis direction from both ends of the upper base portion 44a in the Y-axis direction. And side legs 48a. Each split core 42b arranged on the lower side in the Z-axis direction has a lower base portion 44b as a core bottom extending in the Y-axis direction, and a pair protruding in the Z-axis direction from both ends of the lower base portion 44b in the Y-axis direction. Middle leg portion 46b and side leg portion 48b.

  As shown in FIG. 2, the pair of middle leg portions 46 a are inserted from above in the Z-axis direction into the core leg through-holes 26 a that penetrate the winding tube portion 26 of the bobbin 20. Similarly, the pair of middle leg portions 46b are inserted into the core leg through holes 26a of the bobbin 20 from below in the Z-axis direction, and the tips of the middle leg portions 26b are formed in the core leg through holes 26a. 46a is configured to contact or face the tip of 46a with a predetermined gap.

  Inside the core leg through hole 26a, there is a separation plate portion 27 (see FIG. 2) or a convex portion along the X axis direction so that the core leg through hole 26a is divided in the Y axis direction at the center. It may be formed along the Z-axis direction. The separation plate portion 27 (the same applies to the convex portion) is interposed between the pair of middle leg portions 46a and 46a and between the middle leg portions 46b and 46b. The middle leg portions 46b and 46b are configured so as to face each other at a predetermined gap and not to contact each other inside the core leg through hole 26a. The predetermined gap can be adjusted by the thickness of the separating plate portion 27 in the Y-axis direction.

  The middle leg portions 46a, 46a or the middle leg portions 46b, 46b have an elliptical column shape that is long in the X-axis direction so as to match the inner peripheral surface shape of the core leg through hole 26a in a combined state. However, the shape is not particularly limited, and may be changed in accordance with the shape of the core leg through hole 26a. Moreover, the side leg parts 48a and 48b have an inner concave curved surface shape matched with the outer peripheral surface shape of the winding cylinder part 26, and the outer surface has a plane parallel to the XZ plane. In the present embodiment, the divided cores 42a and 42b may be made of a soft magnetic material such as metal or ferrite, but is not particularly limited.

  In the drawing, the X axis, the Y axis, and the Z axis are perpendicular to each other, the Z axis coincides with the winding axis of the first wire 37 and the second wire 38 described later, and the height of the coil device 10 ( Thickness). In the present embodiment, the lower side of the coil device 10 in the Z-axis direction is the heat radiating plate 80 of the coil device 10 (the installation surface of the coil device 10). Further, the Y axis coincides with the direction in which the pair of split cores 42a and 42a or the pair of split cores 42b and 42b are split. Further, the X-axis coincides with the longitudinal direction of the middle leg portions 46a and 46b (the major axis direction of the ellipse in the elliptical cylinder).

  As shown in FIGS. 2, 5, and 6, end partition walls 28 and 29 are connected to both ends in the Z-axis direction of the wound tube portion 26 of the bobbin 20 in the coil device 10 of the present embodiment. . The end partition walls 28 and 29 are formed substantially parallel to the XY plane so as to extend outward in the radial direction from the winding tube portion 26. Predetermined in the Z-axis direction so that the winding partition walls 23 to 25 protrude radially outward on the outer peripheral surface of the winding tube portion 26 located between the end partition walls 28 and 29 in the Z-axis direction. It is formed at intervals. 5 and 6 are cross sections that pass through a position away from the center of the coil device 10 as shown in FIG. 4, and therefore, FIG. 5 and FIG. The legs 46a and 46b do not appear.

  The end partition walls 28 and 29 and the wound partition walls 23 to 25 formed between the end partition walls 28 and 29, so that the end partition walls 29 and 29 and the wound partition walls 23 to 25 are interposed. As shown in FIG. 5, four winding sections S1 to S4 are formed in order from the bottom in the Z-axis direction. The numbers of the winding partition walls 23 to 25 and the winding sections S1 to S4 are not particularly limited.

  In this embodiment, as shown in FIGS. 5 and 6, the first wire 37 is continuously wound around the winding sections S1 and S2, and the second wire 38 is continuously wound around the winding sections S3 to S4. And it is wound. In the present embodiment, the first wire 37 constitutes a primary coil and the second wire 38 constitutes a secondary coil, but the reverse may be possible. In FIGS. 5 and 6, the first wire 37 and the second wire 38 are shown in a simplified manner, but the first wire 37 and the second wire 38 are arranged around the winding tube portion 26 with a predetermined amount. It is wound spirally with the number of turns.

  In the present embodiment, the winding partition wall 23 shown in FIG. 5 is formed with a communication groove that connects the winding sections S1 and S2 adjacent to each other in the vertical direction. The first wire 37 wound around the winding section S1 is passed through the winding section S2 through the communication groove, and the first wire 37 is placed on the outer periphery of the winding tube portion 26 of the bobbin 20 in the winding sections S1 and S2. Winding is possible.

  Similarly, the winding partition wall 25 shown in FIG. 5 is formed with a communication groove that connects the winding section S3 and the winding section S4 adjacent to each other in the vertical direction. The second wire 38 wound around the winding section S3 is passed through the winding section S4 through the communication groove, and the second wire 38 is placed on the outer periphery of the winding tube portion 26 of the bobbin 20 in the winding sections S3 and S4. Winding is possible.

  Regarding the winding partition wall 24, in order to insulate the first wire 37 and the second wire 38, it is not necessary to form a communication groove similar to these. The communication groove for the first wire 37 and the communication groove for the second wire 38 are preferably formed on the opposite sides in the X-axis direction, but are not particularly limited. 2, on the side of the bobbin 20, the first wire 37 and the second wire 38 wound around the winding sections S1 to S4, and the side legs 48a and 48b of the magnetic core 40, A side insulating cover 50 is attached to insulate.

  As shown in FIG. 5, the section width T1 along the Z-axis in each of the winding sections S1 and S2 around which the first wire 37 is wound is such that only one first wire 37 can enter in the Z-axis direction. It is set. However, the partition width T1 may be set to a width in which two or more first wires 37 can enter. In the present embodiment, the partition widths T1 are preferably all the same, but may be slightly different.

  Further, the section width T2 along the Z axis in each of the winding sections S3 and S4 around which the second wire 38 is wound is set to a width that allows only one second wire 38 to enter in the Z axis direction. The wire winding portions can be separated from each other for each winding section S3, S4. In the present embodiment, the section width T2 along the Z axis in each of the winding sections S3 and S4 may be the same as or different from the section width T1 according to the wire diameter of the second wire 38.

  Further, the heights of the end partition walls 28 and 29 and the winding partition walls 23 to 25 (the length in the radial direction from the winding tube portion 26) are one (one or more) first wires 37 or more. The height is set so that the two wires 38 can enter, and in this embodiment, the height is preferably set so that 2 to 8 layers of wires can be wound. The heights of the end partition walls 28 and 29 and the winding partition walls 23 to 25 are preferably all the same, but may be different. In this embodiment, the winding method of the 1st wire 37 or the 2nd wire 38 wound by winding division S1-S4 is not specifically limited, A normal winding or alpha winding may be sufficient.

  The first wire 37 and the second wire 38 may be constituted by a single wire or may be constituted by a stranded wire, and are preferably constituted by an insulation-coated conductive wire. The outer diameters of the first wire 37 and the second wire 38 are not particularly limited, but when a large current is passed, for example, φ1.0 to φ3.0 mm is preferable. The second wire 38 may be the same as the first wire 37, but may be different.

  The heat sink 80, the case 88, and the potting resin 90 are removed from the coil device 10, and the lower base portion, which is the core bottom portion of the magnetic core 40, is observed obliquely from below (an oblique direction on the Z-axis negative direction side) as shown in FIG. 44b is disposed inside the two bobbin bottoms 21 with both sides in the X-axis direction sandwiched therebetween. As shown in FIG. 5, which is a cross-sectional view, the two bobbin bottom portions 21 and the lower base portion 44 b disposed between the bobbin bottom portions 21 face a heat radiating plate 80 as a heat radiating member.

  As shown in FIG. 3, an uneven shape 21 a is formed on the bobbin bottom 21. The concavo-convex shape 21a has a plurality of fin-like protrusions 21aa extending in parallel with each other along the X-axis direction. As shown in FIG. 5, the fin-like protrusion 21aa continues from the inner side surface 21c sandwiching the lower base portion 44b at the bobbin bottom portion 21 toward the outer side surface 21b that is both ends in the X-axis direction. Further, the fin-like projections 21aa project in the Z-axis negative direction from the end partition wall ridge 28 toward the heat sink 80, and as shown in FIG. 6, the plurality of fin-like projections 21aa are predetermined in the Y-axis direction. Arranged at intervals.

  As shown in FIG. 4 in which the coil device 10 shown in FIG. 1 is observed in a cross section orthogonal to the Z-axis, the uneven shape 21a of the bobbin bottom portion 21 is between the heat sink 80 facing downward (Z-axis positive direction). In addition, a heat dissipation path 92 is formed. As shown in FIG. 4, the heat radiation path 92 is filled with the potting resin 90. As shown in FIGS. 4 and 6, the heat radiation path 92 is formed in the concave portion in the concave and convex shape 21a, that is, between two adjacent fin-like projections 21aa. As shown in FIG. 4, since the fin-like protrusions 21aa are formed in parallel to the X axis, the heat radiation path 92 is continuous from the outer side surface 21b of the bobbin bottom 21 to the lower base 44b.

  As shown in FIG. 4, the heat dissipation path 92 includes a first heat dissipation path 92 a provided between one bobbin bottom 21 disposed on the X-axis negative direction side of the two bobbin bottoms 21 and the heat dissipation plate 80, It has the 2nd heat dissipation path 92b provided between the other bobbin bottom part 21 arrange | positioned among the two bobbin bottom parts 21 at the X-axis positive direction side, and the heat sink 80. The first heat radiation path 92a and the second heat radiation path 92b are both filled with the potting resin 90, and the potting resin 90 connects the first heat radiation path 92a and the second heat radiation path 92b. In the present embodiment, the potting resin 90 not only connects the first heat dissipation path 92a and the second heat dissipation path 92b on the outer periphery of the lower base portion 44b, but also via a gap between the divided lower base portions 44b. The first heat dissipation path 92a and the second heat dissipation path 92b are also connected at the center of the lower base portion 44b.

  As shown in FIG. 5, the tips of the fin-like protrusions 21aa are arranged with a slight gap with respect to the heat radiating plate 80 so that a layer of potting resin 90 is formed between the fins. Is preferred. For example, by making the protruding length of the fin-shaped projection 21aa in the Z direction slightly shorter than the length (thickness) of the lower base portion 44b sandwiched between the bobbin bottom portions 21, the tip of the fin-shaped projection 21aa A layer of potting resin 90 can be formed between the heat sink 80. Further, by making the protruding length in the Z direction of the fin-like protrusion 21aa shorter than the Z direction length of the lower base portion 44b, manufacturing errors of the divided cores 42a and 42b constituting the magnetic core 40, and manufacturing errors of bobbins Even if there exists, the adhesiveness of the magnetic core 40 and the bobbin 20 becomes favorable, and a heat-transfer characteristic improves. Further, the lower base portion 44 b of the magnetic core 40 may be in direct contact with the heat radiating plate 80 or may be connected via a potting resin 90.

  As the potting resin 90, a general potting resin such as silicon or epoxy can be used, but the kind of the potting resin 90 is not particularly limited. Further, as shown in FIG. 4, the potting resin 90 may satisfy all of the heat radiation path 92 formed by the uneven shape 21 a of the bobbin bottom 21, but a part of the heat radiation path 92 is filled with the potting resin 90. The other part of the heat dissipation path 92 may be filled with air. The potting resin 90 functions as a heat transfer material for radiating the heat of the magnetic core 40, the bobbin 20, the first wire 37, and the second wire 38, and connects the magnetic core 40, the bobbin 20 and the heat radiating plate 80. It also functions as a connecting member.

  The bobbin 20 is made of plastic such as PPS, PET, PBT, LCP, and nylon, but may be made of other insulating members. However, in this embodiment, the bobbin 20 is preferably made of a plastic having a high thermal conductivity of, for example, 1 W / m · K or more, and is made of, for example, PPS or nylon. Moreover, it is preferable that the material which comprises the bobbin 20 contains the filler for improving thermal conductivity in addition to a plastic.

  As shown in FIG. 5, the heat radiating plate 80 as the heat radiating member is located on the bottom surface of the coil device 10 and faces the two bobbin bottom portions 21 and the lower base portion 44 b sandwiched between the bobbin bottom portions 21. Is arranged. A frame-shaped case 88 is attached to the heat sink 80 on the positive side of the Z axis, and the magnetic core 40, the bobbin 20, the first wire are placed in a substantially rectangular space surrounded by the heat sink 80 and the case 88. 37, the second wire 38, and the like are disposed. A gap formed between the heat radiating plate 80 and the case 88 and the magnetic core 40 and the bobbin 20 accommodated therein is filled with the potting resin 90.

  The heat radiating plate 80 shown in FIG. 2 is composed of a member having high thermal conductivity such as metal. The material of the case 88 is not particularly limited, but can be made of resin, metal, or the like. For example, the case 88 is made of metal in the same manner as the heat radiating plate 80, so that the case 88 is formed from the outer peripheral side surface. The heat dissipation characteristics can be improved.

  In the present embodiment, as shown in FIG. 5, the bobbin bottom portion 21 that sandwiches the lower base portion 44 b of the magnetic core 40 from both sides in the X-axis direction is connected to the heat radiating plate 80 so that heat can be transferred. For this reason, the heat accumulated in the bobbin 20 around which the coiled first wire 37 or the second wire 38 that generates heat is wound is well transmitted from the bobbin 20 to the heat radiating plate 80 through the bobbin bottom 21. The excessive temperature rise of the coil apparatus 10 can be prevented.

  Further, the magnetic core 40 is connected to the heat radiating plate 80 so that heat can be transferred. Therefore, heat accumulated in the bobbin 20 around which the coiled first wire 37 or the second wire 38 that generates heat is wound is transmitted from the bobbin 20 to the magnetic core 40, and from the magnetic core 40 to the heat radiating plate 80. Is transmitted well and the heat of the coil device 10 is dissipated.

  Moreover, since the uneven | corrugated shape 21a which forms the heat dissipation path 92 as shown in FIG. 4 is formed in the bobbin bottom part 21 in the coil apparatus 10 of this embodiment, the heat dissipation characteristic from the bobbin 20 or the magnetic core 40 is excellent. ing. That is, in the coil device 10, since the uneven shape 21 a is formed, the contact area with the heat dissipation path 92 is increased, and the heat dissipation characteristics are improved. Further, when a plastic containing a conductive filler is adopted as the material of the bobbin 20, the heat dissipation of the bobbin bottom 21 is achieved by forming the uneven shape 21a and reducing the thickness of the resin constituting the bobbin bottom 21. Characteristics can be improved. This is because, even if the bottom of the bobbin has a simple thickness to reduce the distance between the heat sink 80 and the bobbin, the thickness direction of the bobbin bottom (Z-axis positive direction) depends on the orientation of the filler contained in the resin constituting the bobbin. ) May not be sufficiently improved, the coil device 10 has a thin bobbin bottom 21 and a good heat dissipation characteristic at the bobbin bottom 21.

  Furthermore, as shown in FIG. 4, the heat dissipation path 92 is continuous from the outer side surface 21b of the bobbin bottom 21 to the lower base 44b, which is the core bottom, so that the heat around the lower base 44b passes through the heat dissipation path 92. Therefore, the heat radiation characteristics from the magnetic core 44 near the lower base portion 44b and the first wire 37 and the second wire 38 constituting the coil are improved. Further, not only heat dissipation through the heat sink 80 but also heat dissipation characteristics from the outer side surface of the bobbin 20 are improved, so that not only the water cooling system that releases heat intensively from the heat sink 80 but also from other parts than the heat sink 80. Even when a natural cooling system that is required to dissipate heat is employed, the coil device 10 exhibits good heat dissipation characteristics.

  Moreover, in the coil apparatus 10, since the uneven shape 21a has the fin-shaped projections 21aa, the heat radiation path 92 is formed between the fin-shaped projections 21aa to improve the heat radiation characteristics, and also from the bobbin 20 itself, the thickness direction Can perform heat dissipation utilizing the high thermal conductivity in the vertical direction.

  In the coil device 10, the heat accumulated in the bobbin 20 around which the first wire 37 or the second wire 38 is wound follows the heat radiating plate 80, the heat radiating path 92, the potting resin 90, the case 88, and the like. Diversed to the outside of 10. Therefore, it is possible to cope with an increase in current of the coil device 10, the heat dissipation is improved, and the deterioration of the magnetic characteristics due to overheating of the coil portion can be suppressed.

  Furthermore, in the coil device 10 according to the present embodiment, the winding partition wall 23 to separate the wire winding portions adjacent to each other along the winding axis (Z axis) of the first wire 37 and the second wire 38. 25 is formed, insulation is easy even if the outer diameters of the first wire 37 and the second wire 38 are increased, and it is easy to cope with a large current (high output). In addition, conventionally, as the voltage becomes higher, there is an adverse effect that adjacent wires influence each other and it becomes difficult for current to flow. However, in the coil device 10 of this embodiment, the winding partition walls 23 to 25 are used. Therefore, such adverse effects can be reduced, and high frequency characteristics are improved. Furthermore, since the end partition walls 28 and 29 and the wound partition walls 23 to 25 also function as heat dissipation fins, the coil device 10 has excellent heat dissipation characteristics.

  Further, in the present embodiment, in each of the sections S1 to S4, the first wire 37 and the second wire 38 are wound so that only a single wire exists along the winding axis direction. It becomes easy to prevent variations in the number of turns of the first wire 37 and the second wire 38, which contributes to stabilization of coil characteristics. That is, the coupling coefficient between the primary coil and the secondary coil can be strictly controlled.

  Furthermore, in the present embodiment, the divided middle leg portions 46a and 46b of the divided cores 42a and 42b divided into a U-shaped cross section are inserted into the core leg through holes 26a of the bobbin 20. According to experiments by the present inventors, even if the core becomes large by such a configuration, compared with the case where a conventional E-type core is used, at the intersection of the middle leg and the base The generated local stress can be dispersed. Therefore, in the coil device 10 according to the present embodiment, it is possible to effectively suppress the occurrence of cracks or the like even when thermal stress is generated in the core.

  Further, the middle leg portions 46a, 46b, the upper base portion 44a, and the lower base portion 44b in the E-type core configured by combining the split cores 42a, 42b are separated by the split surfaces of the split cores 42a, 42b, A predetermined gap can be formed between the divided surfaces, and heat dissipation is improved. Furthermore, the E-type core is configured by combining a pair of split cores 42a and 42b each having a simple shape, which facilitates the manufacture of the core and reduces the manufacturing cost. Moreover, since the split E-type core as a whole has the same magnetic field lines as the E-type core, the magnetic properties of the core are equivalent to those of a general E-type core.

  Further, in the coil device 10, the heat dissipation path 92 is filled with a resin having a higher thermal conductivity than air, and in such a coil device 10, heat exchange between the bobbin bottom 21 and the heat dissipation plate 80 is particularly performed. It becomes efficient through the potting resin 90. Further, it is considered that the mechanism for radiating the heat of the lower base portion 44 b from the outer side surface 21 b of the bobbin bottom portion 21 through the heat radiation path 92 is more efficient through the potting resin 90. Therefore, such a coil device 10 has good heat dissipation characteristics.

  Further, in the coil device 10, as shown in FIG. 4, the potting resin 90 connects the first heat radiation path 92 a and the second heat radiation path 92 b, so that heat is locally accumulated in a part of the coil device 10. It is possible to effectively prevent problems that occur. Further, when the potting resin 90 connecting the first heat radiation path 92a and the second heat radiation path 92b contacts the lower base portion 44b, the coil device 10 can also efficiently heat the magnetic core 40. Can do.

  As described above, the present invention has been described with reference to the embodiment. However, the present invention is not limited to the above-described embodiment, and many other embodiments are included in the technical scope of the present invention. Needless to say. For example, in another embodiment, the division mode of the magnetic core 40 may be changed. For example, in the coil device 10 described above, the magnetic core 40 is configured by the combination of the U core and the U core that are the split cores 42a and 42b. However, the magnetic core may be assembled by the combination of the U core and the I core. Further, the shape and structure of the bobbin 20, the number of windings and the winding method of the first wire 37 and the second wire 38 are not limited to the illustrated embodiment, and may be variously modified.

  Further, for example, in the coil device 10 according to the first embodiment, the heat radiation path 92 is filled with the potting resin 90, but the heat radiation path 92 may be filled with another material or air. When a fluid such as air is present in the heat dissipation path 92, the heat dissipation of the coil device 10 can be enhanced by adopting a configuration in which the fluid can flow through the heat dissipation path 92.

  Further, the uneven shape 21a formed on the bobbin bottom 21 only needs to form a heat radiation path 92 continuous from the outer side surface 21b of the bobbin bottom 21 to the lower base portion 44b. The fin shape shown in FIGS. It is not limited only to what has protrusion 21aa. FIG. 7 is a cross-sectional view of the coil device 110 according to the second embodiment of the present invention, and corresponds to FIG. 5 of the coil device 10 according to the first embodiment.

  As shown in FIG. 7, the coil device 110 is different in that the uneven shape 121a in the bobbin bottom 121 of the bobbin 120 has a plurality of columnar protrusions 121aa instead of the fin-shaped protrusions 21aa as shown in FIG. Parts other than the uneven shape 121a are the same as those of the coil device 10 according to the first embodiment. Therefore, regarding the coil device 110, only differences from the coil device 10 will be described, and description of points common to the coil device 10 will be omitted.

  As shown in FIG. 7, an uneven shape 121 a is formed on the bobbin bottom 121 of the coil device 110, and the uneven shape 121 a is a plurality of columnar protrusions 121 aa that protrude from the end partition walls 28 toward the heat sink 80. Have The columnar protrusion 121aa is provided intermittently from the inner side surface 121c of the bobbin bottom 121 to the outer side surface 121b.

  Also in the coil device 110, similarly to the coil device 10, a heat dissipation path is formed in the recess formed between the columnar protrusions 121aa, and the heat dissipation path is similar to the heat dissipation path 92 shown in FIG. From the outer side surface 21b to the lower base portion 44b. In addition, the heat dissipation path of the coil device 110 is filled with the potting resin 90 as in the coil device 10. In such a coil device 110, the uneven shape 121a has a plurality of columnar protrusions 121aa, thereby forming a heat dissipation path and improving heat dissipation characteristics, effectively increasing the surface area of the bobbin bottom 121, and the bobbin bottom 121 And the contact area between the heat dissipation path and the heat dissipation path can be increased. Therefore, the coil device 110 also has the same effect as the coil device 10 and has good heat dissipation characteristics.

DESCRIPTION OF SYMBOLS 10,110 ... Coil apparatus 20, 120 ... Bobbin 21, 121 ... Bobbin bottom part 21a, 121a ... Uneven shape 21aa ... Fin-like protrusion 121aa ... Columnar protrusion 21b, 121b ... Outer side surface 21c, 121c ... Inner side surface 28, 29 ... End part Partition wall 22 ... Lead wire installation part 23, 24, 25 ... Winding partition wall 26 ... Winding cylinder part 26a ... Core leg through hole 27 ... Separation plate part 37 ... First wire 38 ... Second wire 40 ... Magnetic Core 40a ... Upper core 40b ... Lower core 42a ... Split core 44a ... Upper base part 44b ... Lower base part 46a, 46b ... Middle leg part 48a, 48b ... Side leg part 50 ... Side insulation cover 54 ... Lead wire insulation cover 80 ... Heat dissipation plate 88 ... Case 90 ... Potting resin 92 ... Heat release path 92a ... First heat release path 92b ... Second heat release path S1, S2, S3 S4 ... winding compartment

Claims (5)

A coil device having a magnetic core, a bobbin, and a coil attached to the bobbin,
A heat dissipating member disposed to face the two bobbin bottoms of the bobbin and the core bottom of the magnetic core disposed between the two bobbin bottoms;
The bobbin bottom is formed with a concavo-convex shape that forms a heat dissipation path with the heat dissipation member,
The coil device, wherein the heat dissipation path is continuous from an outer side surface of the bobbin bottom to the core bottom.   The coil device according to claim 1, wherein at least a part of the heat dissipation path is filled with potting resin.   3. The coil according to claim 1, wherein the uneven shape has a fin-like protrusion that continues from the inner side surface of the bobbin bottom toward the outer side surface and protrudes toward the heat radiating member. apparatus.   The said uneven | corrugated shape has the some columnar protrusion which is provided intermittently from the inner side surface of the said bobbin bottom part to the said outer side surface, and protrudes toward the said heat radiating member, The Claim 1 or Claim 2 characterized by the above-mentioned. The coil apparatus as described. The heat dissipation path is a first heat dissipation path provided between one of the two bobbin bottoms and the heat dissipation member, and between the other bobbin bottom of the two bobbin bottoms and the heat dissipation member. A second heat dissipation path provided in
The coil device according to claim 2, wherein the potting resin connects the first heat dissipation path and the second heat dissipation path.

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