Coil components

Abstract

We provide coil components that improve the cooling performance of busbars. [Solution] The coil component 1 comprises a coil 2, a case 4, a sealing resin, and a busbar 7. The coil 2 is formed by winding a conductive wire 21. The case 4 houses the coil 2 and has a heat dissipation surface 44 on its outer surface that is in contact with or close to an external device, a cooler. The sealing resin 8 is filled into the case 4 and solidified until part or all of the coil 2 is embedded. The busbar 7 conducts electric current. The coil 2 has a cylindrical shape and is housed in the case 4 with its bottom flat surface 23a, which is aligned with the winding shaft 21 of the coil 2, aligned with the heat dissipation surface 44. The case 4 has a groove 6 that extends from the bottom flat surface 23a of the coil on the heat dissipation surface 44, and the busbar 7 is disposed within the groove 6 of the case 4.

Description

Technical Field

[0001] The present invention relates to coil components.

Background Art

[0002] A coil generates magnetic flux according to the number of turns when energized. Therefore, a coil is used as an electromagnetic component that converts electrical energy into magnetic energy or magnetic energy into electrical energy, and is used, for example, as a transformer, a choke coil, or a reactor.

[0003] In recent years, transformers are also mounted in power converters of automobiles such as electric vehicles (EVs) or plug-in hybrid electric vehicles (PHEVs) that are motor-driven by power obtained from a battery. This power converter converts the power of an AC power source into DC power by a converter circuit, converts this DC power into desired AC power by an inverter circuit, and includes electromagnetic components such as a transformer and a reactor.

[0004] Reactors are used in a wide variety of applications. Representative reactors include step-up reactors, series reactors, parallel reactors, current-limiting reactors, starting reactors, shunt reactors, neutral point reactors, and arc-extinguishing reactors.

[0005] Step-up reactors are incorporated into in-vehicle step-up circuits such as drive systems of hybrid vehicles and electric vehicles. Series reactors are connected in series to a motor circuit to limit the current during a short circuit. Parallel reactors stabilize the current sharing between parallel circuits. Current-limiting reactors limit the current during a short circuit and are connected thereto. Starting reactors are connected in series to a motor circuit that protects a machine to limit the starting current. Shunt reactors are connected in parallel to a transmission line to compensate for leading reactive power and suppress abnormal voltages. Neutral point reactors are used to connect between a neutral point and the ground to limit the ground fault current flowing during a ground fault accident in a power system. Arc-extinguishing reactors automatically extinguish the arc generated during a single-line-to-ground fault in a three-phase power system.

[0006] A coil generates heat when an electric current is passed through it. Therefore, a heat dissipation path is necessary to dissipate the heat generated in the coil. For example, a coil component comprises a coil component body containing a core and a coil, a case, and a sealing resin. The case has a closed bottom at one end and an open end at the other, with the bottom surrounded by four side walls. The coil component body is housed in this case. The coil component body is then embedded in the sealing resin that fills the case. The sealing resin is a thermally conductive resin, and the case is, for example, a highly thermally conductive metal case.

[0007] The sealing resin is a thermally conductive resin that absorbs heat from the coil. The case is, for example, a highly thermally conductive metal case. The outer surface of the bottom of the case is in contact with or in close proximity to a cooler, which is an external device separate from the coil components, and serves as a heat dissipation surface. Examples of coolers include heat dissipation sheets, heat sinks, fans, water cooling pipes, and water tanks.

[0008] The sealing resin absorbs heat from the coil, and the case receives the heat from the coil that has flowed into the sealing resin. The case then releases the absorbed heat through its heat dissipation surface for cooling. This sealing resin, case, and the heat dissipation surface of the case form a heat dissipation path for the coil, suppressing the rise in the coil's temperature (see, for example, Patent Document 1).

[0009] Furthermore, this coil component is equipped with a metal busbar for electrical connection to external components. The busbar electrically connects the external components to the coil within the coil component. The busbar is generally wired in the air above the opening of the case. This busbar also generates heat when energized. The heat generated by the busbar is released into the air through the air wiring (see, for example, Patent Document 2). [Prior art documents] [Patent Documents]

[0010] [Patent Document 1] Japanese Patent Publication No. 2023-102370 [Patent Document 2] Japanese Patent Publication No. 2022-183479 [Overview of the project] [Problems that the invention aims to solve]

[0011] In recent years, the current flowing through busbars has increased. Busbars, which are routed in mid-air above the case opening, are far from the cooler, and heat dissipation cannot keep up, causing them to overheat. Embedding the busbars in the case's sealing resin would require a larger case to ensure sufficient insulation distance between the coil and the busbars.

[0012] This invention was proposed to solve the above problems, and its objective is to provide a coil component that improves the cooling performance of the busbar. [Means for solving the problem]

[0013] To achieve the above objective, an embodiment of the present invention provides a coil component disposed in contact with or near a cooler, comprising: a coil formed by winding conductive wire; a case housing the coil and having a heat dissipation surface on its outer surface that is in contact with or near the cooler; a sealing resin that is filled and solidified inside the case until part or all of the coil is buried; and a busbar through which electric current is conducted. The coil has a cylindrical shape and is housed in the case with its bottom flat surface along the winding axis aligned with the heat dissipation surface. The case has a groove extending from the heat dissipation surface at a position away from the bottom flat surface of the coil, and the busbar is disposed within the groove of the case.

[0014] The coil has the shape of a rounded corner tube, consisting of four flat surfaces including the bottom flat surface and four curved surfaces connecting the flat surfaces, and the case accommodates two or more of the coils in a side-by-side arrangement with the winding shafts of the coils running parallel to each other, and the groove may be formed in the inter-coil region sandwiched between the curved surfaces of two adjacent coils.

[0015] It is provided with a core containing a magnetic material, the core has a first leg portion on which the coil is mounted, and a second leg portion that extends between the two adjacent coils and on which the coil is not mounted, and the groove portion may be formed in a region between the coils that is sandwiched between the curved surfaces of the two adjacent coils and through which the second leg portion passes.

[0016] The bus bar may include a bent portion and extend along the heat dissipation surface.

[0017] The bus bar may have a straight portion that extends in the region between the coils along the winding axis of the coil, a first bent portion that extends in an S shape or a crank shape from one side of the case and communicates with one end of the straight portion, and a second bent portion that extends in an S shape or a crank shape from the opposite side of the case facing the one side and communicates with the other end of the straight portion.

[0018] The bus bar may cross the heat dissipation surface of the case from one side to the opposite side facing the one side, and at least a part of the cross section may have an L-shaped configuration.

[0019] The bus bar may be connected to the coil.

[0020] The bus bar may be non-connected to the coil.

Advantages of the Invention

[0021] According to the present invention, the cooling performance of the bus bar included in the coil component can be improved.

Brief Description of the Drawings

[0022] [Figure 1] [[ID=3,5]]It is a top-side perspective view showing a coil component. [Figure 2] It is a perspective view of a coil. [Figure 3] It is a perspective view showing a coil mounted on a core. [Figure 4]It is a perspective view of the core. [Figure 5] It is a cross-sectional view of the coil component. [Figure 6] It is a perspective view of the heat dissipation surface side of the case, showing the state where the bus bar 7 is removed. [Figure 7] It is a perspective view of the heat dissipation surface side of the case. [Figure 8] It is a perspective view showing the bus bar.

Mode for Carrying Out the Invention

[0023] Hereinafter, with reference to the drawings, the coil component of the embodiment of the present invention will be described. In each drawing, for ease of understanding, the thickness, dimensions, positional relationship, ratio, shape, etc. may be emphasized and shown, and the present invention is not limited to those emphases.

[0024] FIG. 1 is a perspective view of the coil component. The coil component 1 is an electromagnetic component that converts electrical energy into magnetic energy, stores it, and releases it. This coil component 1 includes a coil component main body 11, a case 4 having one end with a bottom and the other end open, and a sealing resin 8. The coil component main body 11 is housed in the case 4 from the opening 43. The sealing resin 8 is filled so as to be poured into the case 4 and solidified, and seals the coil component main body 11 in the case 4. The coil component main body 11 includes a core 3 and a plurality of coils 2. The core 3 is an annular body in which one or more rings are connected, and the coil 2 is fitted onto the core 3.

[0025] Coil 2 is a wound body of conductive wire 21 that has an insulating coating such as enamel coating. Coil 2 is formed into a cylindrical shape by winding the conductive wire 21 spirally while shifting the winding position with each turn. Conductive wire 21 is drawn out from coil 2 as lead wires 26. When current is passed through the lead wires 26 from the circuit into which coil component 1 is incorporated, coil 2 generates magnetic flux according to the number of turns. The conductive wire 21 of coil 2 is, for example, a flat rectangular wire, and coil 2 is, for example, an edgewise coil. The wide surface of the conductive wire 21 of coil 2 expands in the direction of the cylindrical radius of coil 2. There are no limitations on the type of conductive wire 21, and other types of wire such as round wire may also be used. A flatwise coil can also be used as coil 2.

[0026] Core 3 is a closed magnetic path that allows the magnetic flux generated by coil 2 to pass through with a permeability higher than that of a vacuum. Core 3 contains a magnetic material such as a powder core, a ferrite core, a metal composite core, or laminated steel plate. A powder core is an annealed powder core formed by compressing magnetic powder. Magnetic powders mainly consist of iron and include pure iron powder, permalloy (Fe-Ni alloy) mainly consisting of iron, Si-containing iron alloy (Fe-Si alloy), Sendust alloy (Fe-Si-Al alloy), or a mixture of two or more of these powders. The magnetic powder may be an amorphous alloy or a nanocrystalline alloy powder. A metal composite core is a core formed by kneading and molding magnetic powder and resin.

[0027] A magnetic gap may be installed in this core 3 to prevent a decrease in inductance during the closed magnetic circuit. The magnetic gap may be, for example, a non-magnetic material, ceramic, non-metallic, resin, carbon fiber, or a composite material of two or more of these, or gap paper.

[0028] Case 4 is box-shaped with an opening 43 on the opposite side of the bottom 42, and has a rectangular parallelepiped-shaped space inside in which the coil component body 11 can be housed. Case 4 is made of metal and has heat dissipation and magnetic shielding properties. Specifically, Case 4 is made of aluminum, aluminum alloy, etc.

[0029] The sealing resin 8 reduces vibration of the coil component body 11 by filling the gap between the coil component body 11 and the case 4. The sealing resin 8 also transfers heat from the coil 2 to the case 4. Furthermore, the sealing resin 8 electrically, chemically, and mechanically protects the coil component body 11 from the external environment, suppressing short circuits, corrosion, and damage to the coil component body 11. This sealing resin 8 is, for example, a thermosetting resin or a thermoplastic resin. Examples of thermosetting resins include epoxy resin, urethane resin, silicone resin, and unsaturated polyester resin. Examples of thermoplastic resins include PPS resin.

[0030] Figure 2 is a perspective view of coil 2, and Figure 3 is a perspective view showing coil 2 mounted on core 3. As shown in Figure 2, the cylindrical shape of coil 2 is, for example, a rounded-corner cylindrical shape. This coil 2 has four flat surfaces 23 that extend along the winding shaft 22, and four curved surfaces 24 interposed between adjacent flat surfaces 23 at the corners. This coil 2 also has end faces 25 located at the beginning and end of the winding of the conductive wire 21, extending perpendicular to the winding shaft 22. The conductive wire 21 is drawn out as lead wires 26 from each end face 25 of coil 2.

[0031] As shown in Figure 3, for example, the coil component body 11 is equipped with four coils 2A to 2D. Each of the coils 2A to 2D is a coil 2, and their winding shafts 22 are arranged to extend in the same direction. Two sets of coils 2, each consisting of two coils 2 made from a single conductive wire 21 and connected by a connecting wire 27, are provided in the coil component body 11. That is, coils 2A and 2B are formed by winding a single conductive wire 21 at two points, respectively. Similarly, coils 2C and 2D are formed by winding a single conductive wire 21 at two points, respectively.

[0032] Coils 2 made from the same conductive wire 21 are arranged side by side with their winding shafts 22 running parallel to each other, and one of their flat surfaces 23 is facing the other. Two sets of coils 2 are arranged vertically with the winding shaft 22 as a common axis, and the end faces 25 of the coils 2 are facing each other.

[0033] Specifically, coils 2A and 2B, made from the same conductive wire 21 and connected by a connecting wire 27, are arranged side by side with their winding shafts 22 running parallel to each other, and one of their flat surfaces 23 is positioned opposite each other. Similarly, coils 2C and 2D, made from the same conductive wire 21 and connected by a connecting wire 27, are arranged side by side with their winding shafts 22 running parallel to each other, and one of their flat surfaces 23 is positioned opposite each other. Coils 2A and 2C are arranged vertically with their winding shafts 22 as a common axis, and their end faces 25 are positioned opposite each other. Coils 2B and 2D are also arranged vertically with their winding shafts 22 as a common axis, and their end faces 25 are positioned opposite each other.

[0034] Figure 4 is a perspective view of core 3. As shown in Figure 4, for example, core 3 is made up of four rings arranged in a row of two vertically and two horizontally on the same plane, and has a shape in which a rectangle is divided into four sections by a cross. A terminal block 35 is installed on core 3. This core 3 has three yoke sections 33, four coil mounting legs 31, and two non-coil mounting legs 32. The three yoke sections 33 are arranged in parallel with a gap between them.

[0035] The two coil-mounted legs 31 and the one non-coil-mounted leg 32 are sandwiched between the central yoke section 33 and the yoke section 33 at one end, and extend perpendicular to the yoke section 33 with a gap between them. Each of these coil-mounted legs 31 has two identical coils 2 attached to it. The non-coil-mounted leg 32 does not have a coil 2 attached to it.

[0036] The other two coil-mounted legs 31 and the other non-coil-mounted leg 32 are sandwiched between the central yoke 33 and the yoke 33 at the other end, and extend parallel to the winding shaft 22 of the coil 2 at a distance from each other. Another pair of coils 2 are separately mounted on each of these coil-mounted legs 31. No coils 2 are mounted on the non-coil-mounted leg 32.

[0037] Both coil-less leg portions 32 are aligned vertically with a common axis, two coil-mounted leg portions 31 are aligned vertically with a common axis on one side of these coil-less leg portions 32, and two other coil-mounted leg portions 31 are aligned vertically with a common axis on the other side of these coil-less leg portions 32.

[0038] Furthermore, the connecting wire 27 extending between the two coils 2, which are formed by shaping a single conductive wire 21, is stretched over the coil-less leg portion 32 above. Above refers to the direction from the bottom of the case 4 towards the opening.

[0039] Figure 5 is a cross-sectional view of the coil component 1. As shown in Figure 5, the core 3 is covered with core molded resin 34. The core molded resin 34 is a resin component formed by molding insulating material. This core molded resin 34 is interposed between the coil 2 and the core 3, insulating the coil 2 from the core 3. Therefore, the core molded resin 34 only needs to cover the area where the coil 2 and the core 3 face each other.

[0040] The core mold resin 34 is made of, for example, epoxy resin, unsaturated polyester resin, urethane resin, BMC (Bulk Molding Compound), PPS (Polyphenylene Sulfide), PBT (Polybutylene Terephthalate), or a composite thereof. A thermally conductive filler may be mixed into the core mold resin 34.

[0041] Case 4 houses the coil component body 11, which consists of a coil 2 mounted on a core 3 covered with core mold resin 34. Case 4 has a bottom 42 and side walls 41 that rise endlessly, surrounding the entire perimeter of the bottom 42. After housing the coil component body 11 in Case 4, Case 4 is filled with sealing resin 8 and the sealing resin 8 is allowed to solidify, so that the heat from the coil 2 and core 3 of the coil component body 11 flows into Case 4 through the sealing resin 8.

[0042] The outer surface of the bottom 42 of case 4 is a heat dissipation surface 44. That is, a cooler, which is an external device separate from the coil component 1, is installed in contact with or close to the heat dissipation surface 44 of case 4. The heat that flows into case 4 is released towards the cooler. Here, the coil component 1 is equipped with a busbar 7 that is electrically connected to the lead wires 26 of the coil 2 by welding. Power is supplied to the coil component body 11 through the busbar 7.

[0043] This busbar 7 is installed on the heat dissipation surface 44 of the case 4. The busbar 7 is also in contact with or close to the cooler and can be easily cooled by the cooler. The busbar 7 is covered with resin 77 by molding. The resin 77 is flush with the heat dissipation surface 44 of the case 4, and the entire busbar 7, including the resin 77, is in contact with or close to the cooler, just like the heat dissipation surface 44.

[0044] The material of resin 77 may be, for example, epoxy resin, unsaturated polyester resin, urethane resin, BMC (Bulk Molding Compound), PPS (Polyphenylene Sulfide), PBT (Polybutylene Terephthalate), or a composite thereof. A thermally conductive filler may be mixed into resin 77.

[0045] The coil component body 11 is housed in the case 4 with one of the flat surfaces 23 of the coil 2 facing the bottom 42 of the case 4, so that the coil 2 is laid down. The flat surface 23 facing the bottom 42 is also called the bottom-side flat surface 23a. Inside the case 4, the bottom-side flat surface 23a is lower than the bottom surface 32a of the non-coil-mounted leg portion 32. In other words, the bottom surface 32a of the non-coil-mounted leg portion 32 is higher than the bottom-side flat surface 23a. The bottom 42 of the case 4 has a bulge 45 that bulges out toward the bottom surface 32a of the non-coil-mounted leg portion 32. The bulge 45 can be extended to have a base that extends over the curved surface 24 of the adjacent coil 2.

[0046] On the back side of this bulge 45, a groove 6 is formed by recessing the heat dissipation surface 44 of the case 4. The busbar 7 is positioned in this groove 6, and is in contact with or close to the cooler. The groove 6 is formed at a location outside the projection area where the bottom flat surface 23a of the coil 2 is projected onto the heat dissipation surface 44, and the busbar 7 passes through a location outside the projection area where the bottom flat surface 23a of the coil 2 is projected onto the heat dissipation surface 44. Therefore, sufficient insulation distance is maintained between the busbar 7 and the coil 2.

[0047] When two or more coils 2 are arranged side by side, it is preferable that the bottom flat surface 23a is outside the projection area projected onto the heat dissipation surface 44, and that a groove 6 is formed in the inter-coil region 44c sandwiched between the curved surfaces 24 of two adjacent coils 2, allowing the busbar 7 to pass through the inter-coil region 44c. This allows the busbar 7 to be positioned by forming a groove 6 in the heat dissipation surface 44 without increasing the size of the coil component 1.

[0048] Furthermore, if the core 3 is equipped with coil-less leg portions 32, it is preferable that the bottom flat surface 23a is outside the projected area projected onto the heat dissipation surface 44, and that a groove 6 is formed in the inter-coil region 44c which extends to include the projected area projected onto the heat dissipation surface 44 by the coil-less leg portions 32, and that the busbar 7 passes through the inter-coil region 44c. This ensures that a sufficiently large inter-coil region 44c is secured without increasing the size of the coil component 1, and that a busbar 7 with a larger surface area can be placed while maintaining a sufficient insulation distance from the coil 2.

[0049] Figure 6 is a perspective view of the heat dissipation surface 44 side of case 4, showing the case with the busbar 7 removed. Figure 7 is a perspective view of the heat dissipation surface 44 side of case 4, including the busbar 7. Figure 8 is a perspective view showing only the busbar 7.

[0050] As shown in Figure 6, the groove 6 extends straight through the inter-coil region 44c from one side 44a of the heat dissipation surface 44 to the opposite side 44b of this side 44a. As shown in Figure 7, there is room for two busbars 7 to pass through this inter-coil region 44c, and a partition wall 63 separating the two busbars 7 rises from the bottom surface of the groove 6 in the center.

[0051] The groove 6 extends from the center of the heat dissipation surface 44 toward one side 44a of the heat dissipation surface 44, and after passing the end face 25 of the coil 2, it cuts out one side 44a of the heat dissipation surface 44 and extends along this side 44a toward both corners of the heat dissipation surface 44. The groove 6 also extends from the center of the heat dissipation surface 44 toward the opposite side 44b of the heat dissipation surface 44, and after passing the end face 25 of the coil 2, it cuts out the opposite side 44b of the heat dissipation surface 44 and extends along this opposite side 44b toward both corners of the heat dissipation surface 44.

[0052] As shown in Figure 7, the busbar 7 is positioned in this groove 6. After leaving the heat dissipation surface 44, the busbar 7 has a vertical plate 71b that extends along the side wall of the case 4 toward the opening 43 of the case 4, and is routed to connect to the coil 2.

[0053] As shown in Figure 8, the busbar 7 is electrically connected to the coil 2 and the external terminal, for example, by having a vertical section 74 welded to the lead wire 26 of the coil 2, or by having a circular terminal 75 at the end of the vertical section 74 that connects to an external terminal, or by having a bar end 76 extending from this circular terminal 75 and welded to the lead wire 26 of the coil 2.

[0054] As shown in Figure 8, the busbar 7 is not routed in a straight line from one side 44a to the opposite side 44b of the heat dissipation surface 44, but rather includes a bend in the section from one side 44a to the opposite side 44b of the heat dissipation surface 44, increasing the distance facing the cooler.

[0055] For example, the busbar 7 has a straight section 71 that extends straight through the inter-coil region 44c. On the other hand, the busbar 7 has a first bent section 72 that bends from a vertical section 74 that comes down from the opening 43 side of the case 4 and extends into the heat dissipation surface 44 from one side 44a of the heat dissipation surface 44. The busbar 7 also has a second bent section 73 that bends from another vertical section 74 that comes down from the opening 43 side of the case 4 and extends into the heat dissipation surface 44 from the opposite side 44b of the heat dissipation surface 44.

[0056] The first bent section 72 and the second bent section 73 communicate with the straight section 71 while bending in a crank-like manner. The first bent section 72 and the second bent section 73 may also be S-shaped, bending in a curved manner. Furthermore, the first bent section 72 and the second bent section 73 may have a more meandering shape.

[0057] For example, the first bent portion 72 cuts out one side 44a and enters the groove portion 6 that widens along the one side 44a from one side 44a of the heat dissipation surface 44. The first bent portion 72 enters from one side 44a of the heat dissipation surface 44 and extends straight toward the end face 25 of the coil 2. Before intersecting the end face 25 of the coil 2, it bends in the direction along the end face 25 of the coil 2 and extends straight along the end face 25 of the coil 2. After entering the inter-coil region 44c, the first bent portion 72 bends in the direction along the winding axis 22 of the coil 2 and communicates with the straight portion 71 in the inter-coil region 44c.

[0058] Furthermore, for example, the second bent portion 73 cuts out the opposing side 44b and enters the groove portion 6 that widens along the opposing side 44b from the opposing side 44b of the heat dissipation surface 44. The second bent portion 73 enters from the opposing side 44b of the heat dissipation surface 44 and extends straight toward the end face 25 of the coil 2. Before intersecting the end face 25 of the coil 2, it bends in the direction along the end face 25 of the coil 2 and extends straight along the end face 25 of the coil 2. After entering the inter-coil region 44c, the second bent portion 73 bends in the direction along the winding axis 22 of the coil 2 and communicates with the straight portion 71 in the inter-coil region 44c.

[0059] The straight section 71 of the busbar 7 has an L-shaped cross-section. That is, the straight section 71 of the busbar 7 is formed of a parallel plate 71a and a vertical plate 71b. The parallel plate 71a extends parallel to the plane over which the heat dissipation surface 44 extends. The vertical plate 71b rises perpendicular to the parallel plate 71a and extends toward the depth of the groove 6. The straight section 71 extends along the heat dissipation surface 44, and the parallel plate 71a tends to undulate, reducing its flatness, but the vertical plate 71b acts as a rib, maintaining the flatness of the parallel plate 71a. As a result, the entire area of ​​the busbar 7 is easily in contact with or close to the cooler.

[0060] Thus, the coil component 1 includes a case 4 that houses the coil component body 11, and a groove 6 is provided on the heat dissipation surface 44 of the case 4. The groove 6 extends to a position away from the bottom flat surface 23a of the coil 2. The busbar 7 is then arranged within the groove 6 of the case 4.

[0061] By extending the groove 6 to a position away from the bottom flat surface 23a of the coil 2, an insulating distance can be ensured between the coil 2 and the busbar 7. As a result, the busbar 7 can come into contact with or be in close proximity to the cooler located on the bottom 42 side of the case 4. Consequently, even if the amount of heat generated in the busbar due to a large current increases, the cooling capacity of the busbar 7 can be improved without increasing the size of the coil component 1.

[0062] Furthermore, the coil 2 has the shape of a rounded corner tube, consisting of four flat surfaces 23, including a flat surface 23a at the bottom, and four curved surfaces 24 connecting the flat surfaces 23. Two or more coils 2 are housed in the case 4 in a side-by-side arrangement with the winding shafts 22 of the coils 2 running parallel to each other. In this case, the groove 6 is formed in the inter-coil region 44c sandwiched between the curved surfaces 24 of two adjacent coils 2.

[0063] Because a large area can be secured between the rectangular and rounded cylindrical coils 2, a wide groove 6 can be formed. Therefore, even if the busbars 7 are placed on the heat dissipation surface 44 side, the area of ​​the busbars 7 can be increased, improving the cooling capacity of the busbars 7.

[0064] In addition to the rectangular-rounded cylindrical shape, the shape of the coil 2 may also be cylindrical. Even if it is cylindrical, a large area can be secured between the coils 2 because it has a curved surface 24. Furthermore, if the groove 6 can be extended to a position away from the flat surface 23a on the bottom side of the coil 2, the busbar 7 can be placed on the heat dissipation surface 44 even if the shape of the coil 2 is rectangular.

[0065] Furthermore, this coil component 1 includes a core 3 containing a magnetic material, and this core 3 has a coil-mounted leg portion 31 which is a first leg portion to which a coil 2 is attached, and a coil-non-mounted leg portion 32 which extends between two adjacent coils 2 and is a second leg portion to which no coil 2 is attached. In this case, the groove portion 6 is sandwiched between the curved surfaces 24 of two adjacent coils and is formed in the inter-coil region 44c through which the coil-non-mounted leg portion 32 passes.

[0066] In the coil component 1 having non-coil leg portions 32, a larger area can be secured between the coils 2, allowing for the formation of wider groove portions 6. Therefore, even if the busbars 7 are placed on the heat dissipation surface 44 side, the area of ​​the busbars 7 can be further increased, further improving the cooling capacity of the busbars 7.

[0067] Furthermore, the busbar 7 is designed to extend along the heat dissipation surface 44, including a bent section. This increases the distance the busbar 7 faces the cooler, thereby improving its cooling capacity. For example, the busbar 7 has a straight section 71, an S-shaped or crank-shaped first bent section 72, and an S-shaped or crank-shaped second bent section 73. However, it is not limited to this, and the busbar 7 may be further meandered.

[0068] Furthermore, the busbar 7 may have a C-shape, passing through the inter-coil region 44c and exiting from the other identical side of the heat dissipation surface 44 sandwiched between one side 44a and the opposite side 44b, or it may have a C-shape, exiting from the other identical side of the heat dissipation surface 44 sandwiched between one side 44a and the opposite side 44b. Alternatively, the busbar 7 may have an S-shape, passing through the inter-coil region 44c, with one end exiting from the side of the heat dissipation surface 44 sandwiched between one side 44a and the opposite side 44b, and the other end exiting from the other side of the heat dissipation surface 44 sandwiched between one side 44a and the opposite side 44b.

[0069] Furthermore, the busbar 7 has an L-shaped cross-section in the inter-coil region 44c. When the busbar 7 is long, it tends to become wavy and its flatness decreases, but the L-shape maintains a high degree of flatness, allowing a large area of ​​the busbar 7 to be in contact with or close to the cooler.

[0070] Furthermore, the busbar 7 should have an L-shaped cross-section in at least a portion of its length from one side 44a to the opposite side 44b of the heat dissipation surface 44. The larger the area with an L-shaped cross-section, the easier it is to maintain the flatness of the busbar. Therefore, the cross-section of the busbar 7 may be L-shaped along its entire length from one side 44a to the opposite side 44b of the heat dissipation surface 44.

[0071] The embodiments of the present invention described above are merely examples and are not limited to those embodiments. The above embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the scope of the invention. The embodiments and their variations are included within the scope of the present invention.

[0072] For example, the coil component 1 of this embodiment is provided with a busbar 7 for electrical connection with the coil 2. However, the type of busbar 7 is not limited. The coil component 1 may also be provided with a busbar 7 that is not connected to the coil 2 but connects to other external devices in the circuit, and this busbar 7 may be arranged in the groove 6 and extend along the heat dissipation surface 44.

[0073] Furthermore, the device may include busbars 7 that are electrically connected to the coil 2 and busbars 7 that are not connected to the coil 2, and both types of busbars 7 may be arranged to extend along the heat dissipation surface 44. Alternatively, the device may include multiple busbars 7 that are electrically connected to the coil 2, with some of the busbars 7 being arranged in the groove 6 and extending along the heat dissipation surface 44. [Explanation of symbols]

[0074] 1. Coil component 11. Coil component body 2 coils 21 Conductive wire 22 reel spindles 23 Flat surface 23a Bottom side flat surface 24 Curved surface 25 End face 26. Leading line 27 Connecting Line 3 cores 31 Coil Mounting Legs 32 Leg section without coil 32a Bottom 33 York 34 Core mold resin 35 Terminal block 4 cases 41 Side wall 42 Bottom 43 Aperture 44 Heat radiation surface 44a One side 44b Opposite side 44c Inter-coil region 45 Bulge 5 Sealing resin 6 grooves 63 Bulkhead 7 Bus Bar 71 Straight section 71a parallel plate 71b vertical board 72 First bending section 73 Second bend 74 Vertical section 75 circular terminals 76 Bar end 77 Resin 8 Sealing resin

Claims

1. A coil component that is in contact with or close to a cooler, A coil formed by winding conductive wire, A case that houses the coil and has a heat dissipation surface on its outer surface that is in contact with or close to the cooler, A sealing resin that is filled and solidified inside the case until part or all of the coil is embedded, A busbar through which electric current flows, Equipped with, The coil has a cylindrical shape and is housed in the case with its bottom flat surface, which is aligned with the winding axis, facing the heat dissipation surface. The case has a groove that extends from the heat dissipation surface at a position away from the bottom flat surface of the coil, The bus bar is disposed within the groove of the case. A coil component characterized by the following.

2. The coil has the shape of a rounded rectangular tube, consisting of four flat surfaces including the bottom flat surface and four curved surfaces connecting the flat surfaces. The case houses two or more of the coils in a side-by-side arrangement with the winding shafts of the coils running parallel to each other. The groove is formed in the inter-coil region sandwiched between the curved surfaces of two adjacent coils. The coil component according to claim 1, characterized by the following:

3. Equipped with a core containing magnetic material, The core has a first leg portion on which the coil is attached, and a second leg portion extending between the two adjacent coils and on which the coil is not attached. The groove is formed in the inter-coil region, sandwiched between the curved surfaces of two adjacent coils, and through which the second leg passes. The coil component according to claim 2, characterized by the following:

4. The busbar extends along the heat dissipation surface, including a bent portion. A coil component according to any one of claims 1 to 3, characterized by the above.

5. The aforementioned busbar is A straight section extending along the winding axis of the coil in the region between the coils, A first bent portion extends in an S-shape or crank shape from one side of the case and communicates with one end of the straight portion, A second bent portion extends in an S-shape or crank shape from the opposite side of the case opposite to the one side and communicates with the other end of the straight portion, Having The coil component according to claim 2 or 3, characterized by the above.

6. The busbar extends across the heat dissipation surface of the case from one side to the opposite side, and at least a portion of its cross-section has an L-shape. A coil component according to any one of claims 1 to 3, characterized by the above.

7. The busbar is connected to the coil. A coil component according to any one of claims 1 to 3, characterized by the above.

8. The busbar is not connected to the coil. A coil component according to any one of claims 1 to 3, characterized by the above.

Images