Coil component

Abstract

To provide a coil component capable of enhancing productivity, while firmly fixing a coil with a tape and ensuring an insulation distance between a core and the coil.SOLUTION: A coil component 100 includes: a core 5; and an assembly 1 including a coil 2 mounted on the core, a bobbin 3 to which the coil 2 is assembled, and a coil fixing tape 4 to fix the coil to the bobbin. The coil has an exposed surface 21 exposed from the bobbin, the core has a facing surface 56 facing the exposed surface, and the exposed surface and the facing surface are arranged with a predetermined gap therebetween. The bobbin includes: a mounting surface where the coil is mounted; four inner walls including inner walls 32b, 32d which rise higher than a height of the coil in a direction perpendicular to the mounting surface along an inner edge of the mounting surface; and notches 321a, 321b provided in the respective inner walls and cutting the respective inner walls to the height of the coil. The inner walls abut on the facing surface of the core, and the coil fixing tape is stuck on the notches 321a, 321b and the exposed surface of the coil.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a coil component in which a coil is fixed to a bobbin with tape. [Background technology]

[0002] Examples of coil components include transformers and reactors used in various electrical devices. The coil component includes a coil and a bobbin. For example, the coil is assembled to the bobbin. The coil is fixed to the bobbin with tape. The coil has an exposed surface that is not covered by the bobbin.

[0003] 7 is a schematic diagram showing a coil component of the prior art. Coil component 200 further includes core 201 made of a magnetic material. For example, core 201 has three legs, and coil 202 is attached to the middle leg. Exposed surfaces 203 of core 201 and coil 202 are arranged opposite each other, and an insulation distance is ensured by a gap S. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 3690725 Summary of the Invention [Problem to be solved by the invention]

[0005] The bobbin 204 to which the coil 202 is attached has an inner wall 206 and an outer wall 207 extending from a mounting surface 205 on which the coil 202 is mounted. The inner wall 206 and the outer wall 207 protrude further toward the core 201 than the coil 202 and abut against the core 201 via a coil fixing tape 208, thereby fixing the positional relationship between the bobbin 204 and the core 201.

[0006] On the other hand, because the bobbin 204 has an inner wall 206 and an outer wall 207, the coil fixing tape 208 does not adhere to the exposed surface 203 of the coil 202. Therefore, there is a risk that the coil 202 may move toward the core 201 due to vibration or the weight of the coil device 200 (shown by the black arrow in FIG. 7). If the coil 202 moves, the gap S cannot be secured, resulting in a problem of insulated wire. Furthermore, if the coil fixing tape 208 is to be adhered to the exposed surface 203 of the coil 202 and the inner circumferential surfaces of the inner wall 206 and outer wall 207, productivity will be reduced.

[0007] The present invention has been made to solve the above-mentioned problems, and its object is to provide a coil component that can improve productivity while firmly fixing the coil with tape and ensuring the insulation distance between the core and the coil. [Means for solving the problem]

[0008] In order to achieve the above object, the coil component of the present invention comprises a core made of a magnetic material, a coil attached to the core, a bobbin to which the coil is assembled, and a coil fixing tape for fixing the coil to the bobbin, wherein the coil has an exposed surface exposed from the bobbin, the core has an opposing surface facing the exposed surface, and the exposed surface and the opposing surface are arranged with a predetermined gap between them, the bobbin has a mounting surface on which the coil is placed and which has an opening in the center, an inner wall that rises along the inner edge of the mounting surface and higher than the height of the coil in a direction perpendicular to the mounting surface, and a notch portion provided in the inner wall that cuts the inner wall to the height of the coil, the inner wall abuts the opposing surface of the core, and the coil fixing tape is attached to the notch portion and the exposed surface of the coil. [Effects of the Invention]

[0009] According to the present invention, it is possible to obtain a coil component that can improve productivity while firmly fixing the coil with tape and ensuring an insulating distance between the core and the coil. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 2 is a perspective view showing the overall configuration of the coil component. [Figure 2] FIG. 2 is a perspective view showing the overall configuration of the assembly. [Figure 3] FIG. 2 is a perspective view showing the overall configuration of the bobbin. [Figure 4] 3 is a cross-sectional view taken along the line AA in FIG. 2. [Figure 5] FIG. [Figure 6] FIG. 4 is an enlarged view showing the positional relationship between the exposed surface and the opposing surface. [Figure 7] FIG. 10 is a schematic diagram illustrating the configuration of a conventional coil component. DETAILED DESCRIPTION OF THE INVENTION

[0011] [Embodiment] Coil components according to embodiments will be described with reference to the drawings. In the drawings, for ease of understanding, dimensions, positional relationships, ratios, shapes, etc. may be emphasized or components may be omitted, but the present invention is not limited to such emphasis.

[0012] FIG. 1 is a perspective view showing the overall configuration of a coil component 100. The coil component 100 is mounted on the surface of a circuit board to form part of a power supply circuit. The coil component 100 of this embodiment is a transformer that converts voltage levels using electromagnetic induction, and is installed in an automobile. Note that the coil component 100 is not limited to a transformer, and may also be a reactor or the like.

[0013] The coil device 100 includes an assembly 1 and a core 5. The assembly 1 is attached to the core 5.

[0014] 2 is a perspective view showing the overall configuration of the assembly 1. The assembly 1 has a coil 2, a bobbin 3, and a tape 4 for fixing the coil.

[0015] The coil 2 is made up of multiple conductive members. The conductive members are, for example, bus bars punched from copper plate. The conductive members are stacked so that their wide surfaces face each other. In this embodiment, four conductive members are stacked to form a three-turn coil 2. Each of the four conductive members has a connection portion 23, which is connected to an adjacent conductive member by soldering or the like. When the coil 2 is viewed from the winding axis direction, each connection portion 23 is arranged so as to protrude outward from a corner. None of the conductive members are covered with an insulating coating such as an enamel coating.

[0016] The coil 2 has an exposed surface 21, which is the surface opposite to the surface that abuts against the mounting surface 31 of the bobbin 3, which will be described later. The exposed surface 21 is not covered by the bobbin 3 and is exposed. The exposed surface 21 is formed on a wide surface of the conductive member that constitutes the coil 2. The exposed surface 21 faces the core 5 when the assembly 1 is attached to the core 5.

[0017] An insulating member 22 is disposed on the exposed surface 21 of the coil 2. In this embodiment, the insulating member 22 is an insulating tape that is provided around the entire circumference of the coil 2 to bundle together multiple conductive members. However, it is sufficient that the insulating member 22 is provided only on the exposed surface 21. Furthermore, insulating paper or insulating film may be used as the insulating member 22 instead of insulating tape. The insulating member 22 insulates the exposed surface 21 of the coil 2 from the core 5 in the vicinity of cutouts 321 and 331 formed in the inner wall 32 or outer wall 33, which will be described later.

[0018] Insulating members 6 are provided between the turns of the coil 2. The insulating members 6 insulate the conductive members. Thin plate-like insulating materials such as insulating paper and insulating film can be used as the insulating member 6. The turns of the coil 2 refer to the individual layers of the coil 2, which are made up of multiple laminated conductive members.

[0019] 3 is a perspective view showing the overall configuration of the bobbin 3. The coil 2 is assembled to the bobbin 3. The bobbin 3 is made of insulating resin. Examples of types of resin that can be used to make the bobbin 3 include epoxy resin, unsaturated polyester resin, urethane resin, BMC (Bulk Molding Compound), PPS (Polyphenylene Sulfide), and PBT (Polybutylene Terephthalate).

[0020] As shown in FIG. 3, the bobbin 3 has a mounting surface 31, an inner wall 32, and an outer wall 33. The mounting surface 31 is a surface on which the coil 2 is mounted. The mounting surface 31 supports a wide surface of the coil 2. More specifically, the wide surface of the coil 2 opposite the exposed surface 21 abuts against the mounting surface 31. The mounting surface 31 has an opening 311. The opening 311 is formed in the center of the mounting surface 311. The outer diameter of the opening 311 is approximately the same size as the middle leg 53 of the core 5 (see FIG. 5) and is slightly smaller than the inner diameter of the coil 2. The opening 311 is approximately rectangular. The middle leg 53 of the core 5 is inserted into the opening 311.

[0021] The inner wall 32 is provided on the edge of the opening 311. The inner wall 32 insulates the center leg 53 of the core 5 from the coil 2. The inner wall 32 consists of four inner walls 32a, 32b, 32c, and 32d. Each inner wall 32a, 32b, 32c, and 32d is provided along each side of the approximately rectangular opening 311, and adjacent inner walls 32a, 32b, 32c, and 32d are connected to each other. In other words, the inner wall 32 is provided around the entire circumference of the opening 311, following the edge of the opening 311. The outer diameter of the inner wall 32 is approximately the same as the inner diameter of the coil 2, and the outer peripheral surface of the inner wall 32 abuts against the inner peripheral surface of the coil 2.

[0022] The inner wall 32 rises from the mounting surface 31 in a direction perpendicular to the mounting surface 31. When the coil 2 is placed on the mounting surface 31, the inner wall 32 rises to a position higher than the height of the coil 2. However, the inner wall 32 has a notch 321. The notch 321 cuts out the inner wall 32 from the upper end of the inner wall 32 toward the mounting surface 31.

[0023] The cutout portion 321 is arranged side by side with the insulating member 22 provided on the exposed surface 21 of the coil 2. The cutout portion 321 and the insulating member 22 are arranged adjacent to each other so that the center of the cutout portion 321 coincides with the center of the insulating member 22. The length of the cutout portion 321 is shorter than the length of the insulating member 22. In other words, the insulating member 22 is provided so as to extend beyond the entire length of the cutout portion 321.

[0024] Two notches 321 are provided. Notch 321a is provided in the center of inner wall 32b. Notch 321b is provided in the center of inner wall 32d. Notches 321a and 321b are provided opposite each other with opening 311 in between.

[0025] Fig. 4 is a cross-sectional view taken along line AA in Fig. 2. In Fig. 4, the coil fixing tape 4 is omitted. As shown in Fig. 4, the cutout portion 321 is cut out until the height of the inner wall 32 becomes substantially the same as the height of the coil 2 when the coil 2 is placed on the placement surface 31. In other words, the height of the inner wall 32 in the portion where the cutout portion 321 is formed becomes substantially the same as the height of the coil 2. Note that the height of the coil 2 here is the height including the insulating member 22, and the upper surface of the inner wall 32 in the portion where the cutout portion 321 is formed becomes flush with the upper surface of the insulating member 22.

[0026] As shown in FIG. 3 , the outer wall 33 is provided on the outer edge of the mounting surface 31. The outer wall 33 rises from the mounting surface 31 in a direction perpendicular to the mounting surface 31. When the coil 2 is placed on the mounting surface 31, the outer wall 33 rises to a position higher than the height of the coil 2. However, the height of the outer wall 33 is lower than that of the inner wall 32. The outer wall 33 insulates the coil 2 from the outer leg 54 of the core 5. Two outer walls 33 are provided. The outer wall 33a faces the inner wall 32b. The outer wall 33b faces the inner wall 32d.

[0027] The outer walls 33a and 33b each have a notch 331. The notch 331 is formed in the center of the outer walls 33a and 33b. The notch 331 of the outer wall 33 and the notch 321 of the inner wall 32 are arranged opposite to each other across a projection area of ​​the mounting surface 31 that is perpendicular to the mounting surface 31. More specifically, the notch 331a of the outer wall 33a faces the notch 321a of the inner wall 32b, and the notch 331b of the outer wall 33b faces the notch 321b of the inner wall 32b. The notches 331 of the outer walls 33a and 33b are arranged side by side with the insulating member 22 provided on the exposed surface 21 of the coil 2. The length of the notches 331 in the outer walls 33a and 33b is approximately the same as the length of the notches 321 in the inner wall 32. In other words, the length of the insulating member 22 is longer than the length of the notches 331 in the outer walls 33a and 33b.

[0028] 4, the cutouts 331a and 331b are formed so that when the coil 2 is placed on the placement surface 31, the height of the outer walls 33a and 33b becomes substantially the same as the height of the coil 2. In other words, the upper surfaces of the outer walls 33a and 33b where the cutouts 331 are formed become substantially flush with the upper surface of the insulating member 22 disposed on the exposed surface 21 of the coil 2.

[0029] As shown in FIG. 2 , the coil fixing tape 4 fixes the coil 2 to the bobbin 3. The coil fixing tape 4 is attached to the coil 2 and the bobbin 3 so as to pass through the cutout portions 321 and 331. The coil fixing tape 4 is attached to the exposed surface 21 from above the insulating member 22. The line width of the coil fixing tape 4 is slightly shorter than the cutout portions 321 and 331. In other words, the line width of the coil fixing tape 4 is shorter than the length of the insulating member 22.

[0030] Two coil fixing tapes 4 are provided. For example, the coil fixing tape 4 is attached so as to start from the notch 321b of the inner wall 32d, move sequentially toward the insulating member 22 arranged on the exposed surface 21 of the coil 2, the notch 331b and outer peripheral surface of the outer wall 33b, the back surface of the bobbin 3 (the surface opposite the mounting surface 31 of the bobbin 3), pass through the inner peripheral surface of the inner wall 32d, and return to the notch 321b of the inner wall 32d. The coil fixing tape 4 is attached for one or more turns.

[0031] FIG. 5 is an exploded perspective view of the coil device 100. The assembly 1 is attached to the core 5. The core 5 is made of a magnetic material. The core 5 forms a magnetic path through which the magnetic flux generated by the coil 2 flows. The core 5 can be made of a powder magnetic core, a ferrite magnetic core, a laminated steel plate, a metal composite core, or the like. A metal composite core is a magnetic material formed by kneading magnetic powder and resin and then hardening the resin.

[0032] The core 5 is made up of a pair of E-shaped members 51 and 52. The E-shaped members 51 and 52 have a center leg 53, a pair of outer legs 54, and a yoke portion 55 connecting the center leg 53 and the pair of outer legs 54. The assembly 1 is attached to the center leg 53. The center leg 53 and the pair of outer legs 54 are arranged side by side so that their extension directions are parallel. The outer legs 54 are arranged on both sides of the center leg 53, with the center leg 53 in between. The E-shaped members 51 and 52 are joined at the tip end surface of the center leg 53 and the tip end surface of the outer legs 54. This makes the core 5 a ring-shaped closed magnetic circuit having a roughly θ shape.

[0033] E-shaped member 51 has an opposing surface 56 that faces exposed surface 21 of coil 2. Opposing surface 56 is a surface of yoke portion 55 that is perpendicular to the winding axis and on which center leg 53 and outer leg 54 are formed.

[0034] 6 is an enlarged view showing the positional relationship between the exposed surface 21 and the opposing surface 56. As shown in FIG. 6, the inner wall 32 abuts against the core 5. Specifically, the inner wall 32 abuts against the opposing surface 56 of the E-shaped member 51. Therefore, the opposing surface 56 and the exposed surface 21 of the coil 2 face each other across a gap S that allows insulation between the E-shaped member 51 and the coil 2. Note that the height of the outer wall 33 is lower than that of the inner wall 32, and therefore the outer wall 33 does not abut against the opposing surface 56 of the E-shaped member 51.

[0035] Furthermore, a tape (not shown) is wound around the outer periphery of the core 5. The tape secures the E-shaped members 51 and 52 so that they do not come apart.

[0036] [Action and effect] As described above, the coil device 100 of this embodiment includes the core 5 made of a magnetic material, the coil 2 attached to the core 5, the bobbin 3 to which the coil 2 is attached, and the coil fixing tape 4 that fixes the coil 2 to the bobbin 3. The coil 2 has an exposed surface 21 exposed from the bobbin 3, and the core 5 has an opposing surface 56 that faces the exposed surface 21. The exposed surface 21 and the opposing surface 56 are arranged with a predetermined gap S therebetween that allows insulation. The bobbin 3 has a mounting surface 31 on which the coil 2 is placed and which has an opening 311 in its center, an inner wall 32 that rises along the inner edge of the mounting surface 31 to a height higher than the height of the coil 2 in a direction perpendicular to the mounting surface 31, and an outer wall 33 that rises along the outer edge of the mounting surface 31 to a height higher than the height of the coil 2 in a direction perpendicular to the mounting surface 31. The inner wall 32 and the outer wall 33 have cutout portions 321 and 331, respectively, that cut out the inner wall 32 or the outer wall 33 to the height of the coil 2. The inner wall 32 abuts against the opposing surface 56 of the core 5. The coil fixing tape 4 is attached to the cutout portions 321 and 331 and the exposed surface 21 of the coil 2.

[0037] In this way, the inner wall 32 and the outer wall 33 have cutout portions 321, 331 that are cut out to the same height as the coil 2, and the coil fixing tape 4 is attached so that it passes through the cutout portions 321, 331. As a result, the exposed surface 21 of the coil 2 is attached by the coil fixing tape 4, so that the coil 2 is firmly fixed to the bobbin 3. Therefore, it is possible to prevent the exposed surface 21 of the coil 2 from approaching the opposing surface 56 of the core 5 due to vibration or the coil device 100's own weight. In addition, the inner wall 32 at the cutout portion 321 and the outer wall 33 at the cutout portion 331 are at the same height as the coil 2, so that the coil fixing tape 4 can be easily attached.

[0038] Furthermore, the inner wall 32 of the bobbin 3 abuts against the opposing surface 56 of the core 5. Therefore, the bobbin 3 does not approach the opposing surface 56 of the core 5. In other words, the movement of the bobbin 3 does not cause the exposed surface 21 of the coil 2 to approach the opposing surface 56 of the core 5.

[0039] This maintains the gap S formed between the exposed surface 21 of the coil 2 and the opposing surface 56 of the core 5. Therefore, the coil device 100 can improve productivity while ensuring the insulation distance between the core 5 and the coil 2.

[0040] In this embodiment, the conductive members constituting the coil 2 are not coated with an insulating film, and an insulating member 22 is provided on the exposed surface 21 of the coil 2. The insulating member 22 is disposed adjacent to the cutout portions 321 and 331, extending beyond the entire length of the cutout portion 321. The coil fixing tape 4 is attached to the exposed surface 21 of the coil 2 via the insulating member 22, thereby fixing the coil 2 to the bobbin 3.

[0041] The inner wall 32 serves to insulate the coil 2 from the center leg 53 of the core 5. The outer wall 33 serves to insulate the coil 2 from the outer leg 54 of the core 5. However, providing the cutouts 321 and 331 in the inner wall 32 and the outer wall 33 shortens the insulation distance between the coil 2 and the center leg 53 or outer leg 54 of the core 5. In particular, if the conductive member that makes up the coil 2 does not have an insulating coating, there is a risk that the insulation between the coil 2 and the center leg 53 or outer leg 54 of the core 5 will not be achieved.

[0042] Therefore, insulating member 22 is disposed on exposed surface 21 of coil 2 close to notches 321 and 331. This insulating member 22 has a total length longer than notches 321 and 331, protrudes from both ends of notches 321 and 331, and is disposed adjacent to notches 321 and 331. Therefore, even if notches 321 and 331 are formed, insulation between coil 2 and center leg 53 and outer leg 54 of core 5 can be ensured.

[0043] Furthermore, the coil 2 and the bobbin 3 are attached to the coil fixing tape 4 via the insulating member 22. Therefore, the insulating member 22 is also fixed by the coil fixing tape 4, and the insulating member 22 is less likely to move due to vibrations of the coil device 100. Insulation between the center leg 53 and outer leg 54 of the core 5 and the coil 2 can be ensured over a long period of time.

[0044] [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.

[0045] In the above embodiment, the insulating member 22 is provided on the exposed surface 21 of the coil 2, but the insulating member 22 is not essential. For example, the insulating member 22 may not be provided, and the conductive members constituting the coil 2 may be coated with an insulating coating to ensure insulation between the center leg 53 and the outer leg 54 of the core 5 and the coil 2. In this case, the exposed surface 21 of the coil 2 is at approximately the same height as the upper surface of the inner wall 32 in which the cutout portion 321 is formed and the upper surface of the outer wall 33 in which the cutout portion 331 is formed.

[0046] The height of the outer wall 33 may be such that it abuts against the opposing surface 56 of the core 5. This allows the outer wall 33 to also fix the positional relationship between the core 5 and the bobbin 3, and more effectively maintain the gap S between the exposed surface 21 of the coil 2 and the opposing surface 56 of the core 5. [Explanation of symbols]

[0047] 100 Coil parts 1 assembly 2 coils 21 Exposed surface 22 Insulating material 23 Connection 3 bobbins 31 Placement surface 32, 32a, 32b, 33c, 33d interior walls 321 Notch 33, 33a, 33b Exterior wall 331 Notch 4 Coil fixing tape 5 cores 51, 52 E-shaped members 53 Middle leg 54 Outer leg 55 Yoke 56 Opposite surface 6. Insulating material 200 Coil parts 201 Core 202 Coil 203 Exposed surface 204 Bobbin 205 Placement surface 206 Interior wall 207 Exterior Wall 208 Coil fixing tape

Claims

1. a core made of a magnetic material; a coil attached to the core; a bobbin to which the coil is attached; a coil fixing tape for fixing the coil to the bobbin; Equipped with the coil has an exposed surface exposed from the bobbin, the core has an opposing surface facing the exposed surface, The exposed surface and the opposing surface are disposed with a predetermined gap therebetween, The bobbin is a mounting surface on which the coil is placed and which has an opening in the center; an inner wall extending along an inner edge of the mounting surface and rising to a height higher than the height of the coil in a direction perpendicular to the mounting surface; a notch provided on the inner wall, the notch cutting the inner wall to the height of the coil; and the inner wall abuts against the opposing surface of the core, the coil fixing tape is attached to the cutout portion and the exposed surface of the coil; A coil component characterized by:

2. The conductive member constituting the coil is not covered with an insulating coating, An insulating member is provided on the exposed surface of the coil, the insulating member is disposed adjacent to the cutout portion over an entire length of the cutout portion, the coil fixing tape is attached to the exposed surface of the coil via the insulating member, thereby fixing the coil to the bobbin; The coil component according to claim 1 ,

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