Coil parts

Abstract

To provide a coil component in which a contact area of the coil component with a heat dissipation member is increased and heat dissipation is improved.SOLUTION: A coil component 10 abutting on a heat dissipation member 4 having elastic force includes: a core 1; a coil 2 mounted on the core 1; and a resin member 3 interposed between the core 1 and the coil 2. The resin member 3 includes a cylindrical winding unit 31 around which the coil 2 is wound, and flange units 32 that are provided at both end portions of the winding unit 31 and surround the coil 2. The flange unit 32 includes a protruding unit 321 that protrudes toward the heat dissipation member 4 from an outer peripheral surface of the coil 2. The protruding unit 321 is tapered toward a tip, and enters an inside of the heat dissipation member 4 when the coil component 10 is in contact with the heat dissipation member 4.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a coil component that abuts against a heat dissipation member made of elastic resin. [Background technology]

[0002] Coil components such as transformers and reactors are used in a variety of applications, including office equipment, solar power generation systems, and automobiles. Coil components consist of a coil wound around the outer periphery of a toroidal core made of magnetic material. The inner and outer periphery of the coil are covered with a resin material.

[0003] Coil components generate heat when current flows through the coil. If the temperature of the coil component increases, the magnetic properties of the core may change, which may result in a deterioration of the magnetic properties of the coil component. Therefore, the heat generated by the coil component needs to be released to the outside of the coil component. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-139644 Summary of the Invention [Problem to be solved by the invention]

[0005] A known method for dissipating heat from a coil component to the outside is to use a heat dissipation member made of elastic resin. Fig. 8 is a diagram showing a conventional coil component in contact with a heat dissipation member. As shown in Fig. 8, coil component 100 is pressed against heat dissipation member 104, and coil 102 and core 101 are brought into contact with heat dissipation member 104, causing heat from coil component 100 to be dissipated to the outside of coil component 100 via heat dissipation member 104.

[0006] Resin members 103 are provided between the coils 102 and between the coils 102 and the core 101 to ensure an insulating distance. The resin members 103 have flange portions 132 that protrude beyond the end faces of the coils 102 and the core 101. The flange portions 132 are plate-shaped members that have the same thickness from their base to their tip. That is, the tip of the flange portions 132 is a rectangular flat surface. The coil device 100 presses the flange portions 132 against the heat dissipation member 104 so that the coils 102 and the core 101 abut against the heat dissipation member.

[0007] Because heat dissipation member 104 is made of elastic resin, when flange portion 132 is pressed against it, it tends to return to its original position due to a repulsive force. However, if the tip of flange portion 132 has a rectangular flat surface, heat dissipation member 104 will not return all the way to the base of flange portion 132, as shown by the thick solid circle in Fig. 8, and there will be areas where heat dissipation member 104 is not in contact with coil component 100, such as coil 102 or core 101. For this reason, it is desirable to eliminate areas that are not in contact with heat dissipation member 104 and increase heat dissipation efficiency.

[0008] The present invention has been proposed to solve the above-mentioned problems, and its object is to provide a coil component that can increase the contact area of ​​the coil component with a heat dissipation member and improve heat dissipation performance. [Means for solving the problem]

[0009] In order to achieve the above object, the coil component of the present invention is a coil component that abuts against a heat dissipation member having elastic force, and comprises a core, a coil attached to the core, and a resin member interposed between the core and the coil, wherein the resin member has a cylindrical winding portion around which the coil is wound, and flange portions provided at both ends of the winding portion and surrounding the coil, the flange portions having protrusions that protrude toward the heat dissipation member beyond the outer peripheral surface of the coil, the protrusions tapering toward the tip, and penetrating into the heat dissipation member when the coil component is in contact with the heat dissipation member. [Effects of the Invention]

[0010] According to the present invention, a coil component capable of improving heat dissipation properties can be obtained. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a plan view showing an overall configuration of a coil component according to an embodiment; [Figure 2] 2 is a cross-sectional view taken along the line AA in FIG. 1. [Figure 3] FIG. 2 is a perspective view showing the overall configuration of a resin member. [Figure 4] 2 is a cross-sectional view taken along the line BB in FIG. 1, showing a state in which the coil component is in contact with the heat dissipation member. [Figure 5] 10A and 10B are diagrams showing the shape of a flange portion in another embodiment. [Figure 6] 10A and 10B are diagrams illustrating a state in which a coil component according to another embodiment is in contact with a heat dissipation member. [Figure 7] 10A and 10B are diagrams illustrating a state in which a coil component according to another embodiment is in contact with a heat dissipation member. [Figure 8] FIG. 10 is a diagram showing a state in which a conventional coil component is in contact with a heat dissipation member. DETAILED DESCRIPTION OF THE INVENTION

[0012] (Embodiment) The configuration of a coil component according to this embodiment will be described with reference to the drawings. Fig. 1 is a plan view showing the overall configuration of a coil component according to this embodiment (heat dissipation members are also shown by dashed lines). Fig. 2 is a cross-sectional view taken along line AA in Fig. 1. Note that this embodiment will be described assuming that the coil component 10 is a transformer, but the coil component 10 is not limited to a transformer.

[0013] The coil component 10 is a device that converts voltage levels using electromagnetic induction, and is used in DC / DC converters, inverters, etc. The coil component 10 of this embodiment is a small component measuring 50 mm in length and 50 mm in width. As shown in FIGS. 1 and 2 , the coil component 10 includes a core 1, a coil 2, and a resin member 3. The coil 2 is attached to the core 1. The resin member 3 is interposed between the core 1 and the coil 2, insulating them from each other. The coil component 10 is placed on a heat dissipation member 4 to dissipate heat from the coil component 10 to the outside.

[0014] The core 1 is made of a magnetic material, such as a powder magnetic core, a ferrite magnetic core, a metal composite core, or a laminated steel plate. A powder magnetic core is made by annealing a powder compact made by compressing magnetic powder. The magnetic powder is primarily iron-based, and examples thereof include pure iron powder, iron-based permalloy (Fe-Ni alloy), Si-containing iron alloy (Fe-Si alloy), sendust alloy (Fe-Si-Al alloy), amorphous alloy, nanocrystalline alloy powder, and a mixture of two or more of these powders. A metal composite core is made by kneading and hardening magnetic powder and resin.

[0015] The core 1 is composed of a pair of E-shaped cores. The E-shaped core is composed of a center leg on which the coil is attached, a pair of outer legs arranged on either side of the center leg, and a yoke portion connecting the center leg and the pair of outer legs. The core 1 is formed into an annular shape by joining the ends of these E-shaped cores, and forms a closed magnetic circuit through which the magnetic flux generated by the coil 2 passes. Note that in this embodiment, the core 1 is composed of a pair of E-shaped cores, but is not limited thereto, and various other shaped cores such as a U-shaped core or an I-shaped core can be used.

[0016] The coil 2 is composed of a single conductive member that is insulated with enamel or the like. In this embodiment, the coil 2 is made of a round wire wound in multiple layers (see FIG. 4), but it may also be made of a plate-shaped wire wound edgewise or flatwise. As shown in FIG. 2, the outer shape of the coil 2 is a shape in which four flat surfaces and four curved surfaces are alternately connected. Two coils 2 are provided, one of which is the primary coil and the other is the secondary coil. These two coils 2 are provided on the center legs of the core 1 with a resin member 3 sandwiched between them.

[0017] At least a portion of the periphery of the coil 2 is surrounded by the resin member 3. In this embodiment, the coil 2 has an exposed surface 21 that is not surrounded by the resin member 3 (see FIG. 4). The exposed surface 21 is the outer peripheral surface of the coil 2 and is the surface that abuts against the heat dissipation member 4. In other words, the exposed surface 21 abuts against the heat dissipation member 4 directly, without the resin member 3 in between. The exposed surface 21 is formed on a flat surface of the outer shape of the coil 2. The exposed surface 21 and the outer peripheral surface of the core 1 that faces the heat dissipation member 4 (the outer peripheral surface of the yoke portion) are located on the same plane.

[0018] Examples of the resin that can be used to form the resin member 3 include epoxy resin, unsaturated polyester resin, urethane resin, bulk molding compound (BMC), polyphenylene sulfide (PPS), and polybutylene terephthalate (PBT). It is particularly desirable to use a resin with high thermal conductivity. By covering the coil 2 with a resin with high thermal conductivity, the heat from the coil 2 can be transferred to the heat dissipation member 4 more efficiently.

[0019] Fig. 3 is a perspective view showing the overall configuration of the resin member 3. Fig. 4 is a cross-sectional view taken along line BB in Fig. 1, showing a state in which the coil component is placed on the heat dissipation member 4. The coil 2 is wound around the resin member 3. In other words, the resin member 3 and the coil 2 are not integrally formed by molding.

[0020] The resin member 3 has a winding portion 31 and a flange portion 32. The winding portion 31 is the portion around which the coil 2 is wound. The winding portion 31 is formed in a cylindrical shape, and the center leg of the core 1 is provided inside. The winding portion 31 is interposed between the inner circumferential surface of the coil 2 and the center leg of the core 1. The inner circumferential surface of the coil 2 is the surface of the coil 2 into which the center leg of the core 1 is inserted. Two winding portions 31 are provided, and each winding portion 31 is arranged so that the central axes of the holes into which the center leg of the core 1 is inserted are coaxial.

[0021] The flange portion 32 is a plate-like member that is larger than the outer shape of the winding portion 31. The flange portion 32 has a hole into which the center leg of the core 1 is inserted, and the central axis of this hole is arranged so as to be coaxial with the central axis of the hole in the winding portion 31. The flange portion 32 is molded integrally with the winding portion 31. Three flanges 32 are provided, one between the winding portions 31 and one between the winding portion 31 and the yoke portion of the core 1. The flange portion 32 is provided so as to surround the side of the coil 2. The winding portion 31 and the flange portion 32 define a U-shaped cross section. The coil 2 is wound in this defined space, which becomes the coil housing.

[0022] The flange portion 32 has a protruding portion 321 that protrudes outward beyond the exposed surface 21 of the coil 2 when the coil component 10 is placed on the heat dissipation member 4. The protruding portion 321 penetrates into the heat dissipation member 4 when the coil component 10 is placed on the heat dissipation member 4. The flange portion 32 penetrating into the heat dissipation member 4 does not only mean that the entire flange portion 32 penetrates into the heat dissipation member 4, but also means that only a portion of the flange portion 32 penetrates into the heat dissipation member 4. Furthermore, penetrating into the interior refers to a state in which the flange portion 32 penetrates further into the interior than the upper surface (the surface that abuts against the exposed surface 21) of the heat dissipation member 4.

[0023] The protruding portion 321 tapers toward the tip. That is, the protruding portion 321 narrows toward the tip. In this embodiment, the width of the protruding portion 321 in the winding axis direction gradually decreases toward the tip, and the protruding portion 321 has an isosceles triangular cross section. The base of the protruding portion 321 with an isosceles triangular cross section is the starting point for the tapered shape of the flange portion 32. Note that, as shown in FIG. 4 , the protruding portion 321 has an acute angle, but it may be rounded to facilitate the flow of resin. That is, the winding portion 31, the flange portion 32, and the protruding portion 321 are formed by injecting resin into a mold, filling the resin throughout the mold, and solidifying the resin. Therefore, forming the protruding portion 321 with a rounded angle rather than forming it with an acute angle makes it easier for the resin injected into the mold to flow to the tip of the protruding portion 321.

[0024] The starting point of the tapered portion of protrusion 321 is located on the upper surface of heat dissipation member 4. Exposed surface 21 of coil 2 and the outer peripheral surface of core 1 facing heat dissipation member 4 are located at the same height, and the base of protrusion 321, which tapers into an isosceles triangle shape, is located on the same plane as exposed surface 21 of coil 2 and the outer peripheral surface of core 1. Looking at flange portion 32 as a whole, the starting point of the tapered shape of flange portion 32 is located on the same plane as exposed surface 21 and the outer peripheral surface of core 1.

[0025] The protrusion 321 has the function of insulating the adjacent coil 2 or the core 1 from the coil 2. The distance between the two sides of this protrusion 321 is the creepage distance. Therefore, by adjusting the lengths of the two sides, it is possible to insulate the adjacent coil 2 or the core 1 from the coil 2.

[0026] The heat dissipation member 4 abuts against the coil component 10 and dissipates heat from the coil component 10 to the outside. The heat dissipation member 4 is made of elastic resin. It is preferable to use a resin material with high thermal conductivity. The heat dissipation member 4 can be a sheet-like material such as a heat dissipation sheet, or a filler that is filled into a container and hardened into an elastic state. In this embodiment, the heat dissipation member 4 is a heat dissipation sheet formed from a single sheet.

[0027] The heat dissipation member 4 is formed in a rectangular shape and abuts against the entire exposed surface 21 of the coil 2 and a portion of the yoke portion of the core 1. That is, the heat dissipation member 4 is sized to abut against the entire exposed surface 21 of the coil 2 and a portion of the yoke portion of the core 1. The exposed surface 21 of the coil 2 and the portion of the yoke portion of the core 1 that abut against the heat dissipation member 4 form abutment surfaces 22, 11 (see FIG. 4). The coil component 10 is fixed by a fixing portion (not shown) with the exposed surface of the coil 2 and a portion of the yoke portion of the core 1 abutting against the heat dissipation member 4. The heat dissipation member 4 may be provided in the coil component 10 as a constituent member of the coil component 10, or may be disposed on the installation object on which the coil component 10 is installed.

[0028] Next, a case where the coil component 10 in this embodiment is placed on the heat dissipation member 4 will be described. The heat dissipation member 4 is already provided at the installation location of the coil component 10. First, the coil component 10 is held so that the protruding portion 321 faces the heat dissipation member 4, and in this state, the coil component 10 is brought close to the heat dissipation member 4 so that it comes into contact with it.

[0029] When the protruding portion 321 of the coil component 10 comes into contact with the heat dissipation member 4, the coil component 10 is pressed against the heat dissipation member 4. The protruding portion 321 penetrates into the heat dissipation member 4 from its tip. At this time, the protruding portion 321 narrows in cross section to an isosceles triangular shape as it approaches the tip, so the heat dissipation member 4, which is made of elastic resin, is more likely to return to the base of the protruding portion 321 (the base of the isosceles triangular protruding portion 321) than if the tip were flat and rectangular (see FIG. 8).

[0030] Then, when the protruding portion 321 has penetrated into the heat dissipation member 4 up to the starting position of the taper of the flange portion 32, the coil component 10 is no longer pressed against the heat dissipation member 4. At this time, as shown in FIG. 4, the heat dissipation member 4 is in contact with the entire exposed surface 21 of the coil 2 and the outer peripheral surface of the core 1. In other words, there is no space between the coil component 10 and the heat dissipation member 4, and they are in close contact. In this state, the coil component 10 is fixed with a fixing portion (not shown).

[0031] (Action and effect) As described above, the coil device 10 of this embodiment includes the core 1, the coil 2 attached to the core 1, and the resin member 3 that insulates the core 1 from the coil 2. The resin member 3 has a flange portion 32, and the flange portion 32 has a protruding portion 321 that protrudes further toward the heat dissipation member 4 than the outer circumferential surface of the coil 2. The protruding portion 321 tapers toward the tip.

[0032] As a result, when the coil component 10 is pressed onto the heat dissipation member 4 and placed thereon, no space is created between the coil component 10 and the heat dissipation member 4, and they can be tightly attached to each other. Therefore, compared to the coil component 100 having the conventional flange portion 132 shown in FIG. 8 , the coil component 10 can transfer heat to the heat dissipation member 4 more efficiently, improving the heat dissipation performance of the coil component 10. Furthermore, improving the heat dissipation performance of the coil component 10 allows the wire diameter of the windings that make up the coil 2 to be reduced, thereby enabling the coil 2 to be made more compact, and as a result, the coil component 10 can be made more compact.

[0033] In particular, the coil 2 has an exposed surface 21 that is not surrounded by the resin member 3, and the heat dissipation member 4 abuts against the exposed surface 21. Because the coil 2 is a heat source, providing the coil 2 with the exposed surface 21 and having the heat dissipation member 4 abut directly against this exposed surface 21 further improves the heat dissipation performance of the coil component 10. Furthermore, the protruding portion 321 tapers in cross section into an isosceles triangle shape toward the tip, and the tip has an acute angle. Therefore, there is less resistance when the protruding portion 321 is pressed against the heat dissipation member 4, no space is created between the coil component 10 and the heat dissipation member 4, and it is easy to bring the coil component 10 and the heat dissipation member 4 into close contact.

[0034] The starting point of the protrusion 321 is located on the same plane as the exposed surface 21 of the coil 2. As a result, by pressing the coil component 10 against the heat dissipation member 4 up to this starting point, no space is created between the exposed surface 21 of the coil 2 and the heat dissipation member 4, thereby further improving adhesion. In addition, excessive pressing of the coil component 10 against the heat dissipation member 4 can be prevented. Pressing the coil component 10 excessively against the heat dissipation member 4 may damage the coil component 10. However, by locating the starting point of the protrusion 321 on the same plane as the exposed surface 21, as in this embodiment, this starting point can be used as a marker for determining the degree of pressing. In other words, by pressing the coil component 10 until this starting point is located on the top surface of the heat dissipation member 4, the exposed surface 21 and the heat dissipation member 4 will be in close contact with each other. This not only improves heat dissipation, but also improves work efficiency.

[0035] The heat dissipation member 4 is a single heat dissipation sheet, and the core 1 and the coil 2 each have an outer peripheral surface that abuts against the heat dissipation member 4. As a result, the heat dissipation member 4 abuts not only the coil 2 but also the core 1, allowing the heat of the coil device 10 to be dissipated to the outside more efficiently.

[0036] Furthermore, for example, if the heat dissipation member 4 were composed of multiple heat dissipation sheets, the number of materials would increase and the installation labor would also increase. In particular, in the case of a small coil component 10 such as that of this embodiment, the size of each heat dissipation sheet would be very small, requiring delicate work. Furthermore, if the heat dissipation sheets are misaligned, there would be areas where the heat dissipation sheets are not in contact with the exposed surface 21 of the coil 2 or the outer peripheral surface of the core 1, which could result in a deterioration in heat dissipation efficiency. However, by configuring the heat dissipation member 4 from a single heat dissipation sheet, the number of materials can be reduced and workability can be improved. Furthermore, by configuring the heat dissipation member 4 from a single heat dissipation sheet, even if the heat dissipation member 4 is slightly misaligned, the heat dissipation member 4 can be in contact with the entire exposed surface 21 of the coil 2 or the outer peripheral surface of the core 1.

[0037] In particular, the outer peripheral surface of the core 1 and the exposed surface 21 of the coil 2 that come into contact with the heat dissipation member 4 are located on the same plane. This prevents the heat dissipation member 4 from coming into contact with only one of the outer peripheral surface of the core 1 or the exposed surface 21 of the coil 2.

[0038] Furthermore, in this embodiment, the position of the starting point of the protrusion 321 is at the same height as the exposed surface 21 of the coil 2 and the outer peripheral surface of the core 1. Therefore, if the coil component 10 is placed on the heat dissipation member 4 so that the position of the starting point is located on the upper surface of the heat dissipation member 4, the heat dissipation member 4, the exposed surface 21 of the coil 2, and the outer peripheral surface of the core 1 can be brought into close contact with each other.

[0039] (Other embodiments) Although the present specification describes an embodiment of the present invention, this embodiment is presented as an example and is not intended to limit the scope of the invention. The above-described embodiment can be embodied 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 modifications are included within the scope and spirit of the invention, as well as within the scope of the invention and its equivalents as set forth in the claims.

[0040] In the above embodiment, the tapered shape of the protrusion 321 has an isosceles triangular cross section, but the shape is not limited to this. For example, the tapered shape of the protrusion 321 may be a shape formed by combining two identical arcs, as shown in FIG. 5(a). Even in this case, there is less resistance when pressing the protrusion 321 against the heat dissipation member 4, making it easier to bring the coil device 10 and the heat dissipation member 4 into close contact.

[0041] 5(b), the protrusion 321 may have a curved shape, or may taper in a stepped shape as shown in Fig. 5(c). In this case, the tip of the protrusion 321 is not sharp, so that breakage or cracking of the heat dissipation member 4 can be suppressed.

[0042] Furthermore, although the tapering of the protrusion 321 starts on the upper surface of the heat dissipation member 4, the position of the starting point is not limited to this. For example, the starting point of the tapering of the protrusion 321 may be lower than the upper surface of the heat dissipation member 4, i.e., inside the heat dissipation member 4, as shown in FIG. 6 . In other words, the protrusion 321 may be configured with a flat portion 33 of the same width and a tapered portion 34 that tapers toward the tip. However, it is desirable that the length of the flat portion 33 (the length in the extension direction of the flange portion 32) be shorter than the tapered portion 34. With this configuration, the heat dissipation member 4 can be formed up to near the base of the flange portion 32.

[0043] 4 has a bilaterally symmetrical shape like an isosceles triangle, but is not limited to bilateral symmetry. For example, as shown in FIG. 7, if the height of the end face of core 1 facing heat dissipation member 4 is higher than the height of the end face of coil 2 facing heat dissipation member 4, the tapered shape of protrusion 321 may be tapered from the height of the end face of core 1 on one side and from the height of the end face of coil 2 on the other side.

[0044] In the above embodiment, the coil 2 has an exposed surface 21 that is not surrounded by the resin member 3 and that abuts against the heat dissipation member 4, but the coil 2 may be covered by the resin member 3 and abut against the heat dissipation member 4. Even in this case, the resin member 3 near the base of the protrusion 321 abuts against the heat dissipation member 4, so that heat from the coil 2 can be efficiently transferred to the heat dissipation member 4 via the resin member 3, improving the heat dissipation performance of the coil device 10.

[0045] In the above embodiment, the resin member 3 is separate from the coil 2, and the coil 2 is wound around the resin member 3, but this is not limiting. The coil 2 may be a so-called molded coil, in which the coil 2 is molded in the resin member 3. In this case, the protrusion 321 may be formed on the flange portion 32 during molding.

[0046] In the above embodiment, the exposed surfaces 21 of the two coils 2 were located in the same plane as the outer peripheral surface of the core 1 (the outer peripheral surface of the yoke portion) facing the heat dissipation member 4, but it is sufficient that at least one of the exposed surfaces 21 is located in the same plane as the outer peripheral surface of the core 1 (the outer peripheral surface of the yoke portion). [Explanation of symbols]

[0047] 10 Coil parts 1 core 11 Contact surface 2 coils 21 Exposed surface 22 Contact surface 3 Resin parts 31 Winding section 32 Flange 321 Protrusion 33 Flat area 34 Tapered section 4 Heat dissipation material 100 Coil parts 101 cores 102 Coil 121 Exposed surface 103 Resin parts 132 flange 104 Heat dissipation material

Claims

1. A coil component that abuts against a heat dissipation member having elasticity, The core and a coil attached to the core; a resin member interposed between the core and the coil; Equipped with The resin member is a cylindrical winding portion around which the coil is wound; Flange portions provided at both ends of the winding portion and surrounding the coil; and the flange portion has a protruding portion that protrudes toward the heat dissipation member beyond the outer circumferential surface of the coil, the protrusion is tapered toward the tip and penetrates into the heat dissipation member when the coil component is in contact with the heat dissipation member; A coil component characterized by:

2. an outer circumferential surface of the coil facing the heat dissipation member is an exposed surface on which the resin member is not provided, the heat dissipation member is in contact with the exposed surface; The coil component according to claim 1 ,

3. the exposed surface is a flat surface, the tapered starting point of the protrusion is located on the same plane as the exposed surface; The coil component according to claim 2 ,

4. the core and the coil each have a contact surface that contacts the heat dissipation member, the heat dissipation member is a single heat dissipation sheet extending over the contact surface of the core and the contact surface of the coil; 4. The coil component according to claim 1, wherein:

5. the abutment surface of the core and the abutment surface of the coil are flat surfaces, the abutment surface of the core and the abutment surface of the coil are located on the same plane; The coil component according to claim 4 ,

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