Coil component

Abstract

The invention relates to a coil component. In a coil component wound with two wires, electrostatic capacitance generated between a winding portion of a first wire and a winding portion of a second wire wound in a winding core portion in a state of being adjacent to each other is reduced. In a winding portion (29) of a first wire material (27) and a winding portion (30) of a second wire material (28) in which a winding core portion is wound in a state of being adjacent to each other, insulating films (33, 34) have a large-diameter portion (35) and small-diameter portions (37, 38) having smaller outer diameters than the large-diameter portion (35). The large-diameter portions (35, 36) and the small-diameter portions (37, 38) are distributed across a plurality of locations along the extension direction of the wires (27, 28). A gap (39) is formed between the first winding portion (29) and the second winding portion (30) due to a difference in radial dimensions between the large-diameter portions (35, 36) and the small-diameter portions (37, 38), and the gap (39) contributes to a reduction in capacitance.

Description

Technical Field

[0001] The present invention relates to a coil component having a structure in which at least two wires are wound around a winding core portion provided on a bobbin, and more particularly to a form of an insulating coating provided on the wires. Background Art

[0002] As a coil component related to the present invention, there is, for example, a coil component constituting a common mode choke coil or a transformer. The coil component constituting the common mode choke coil or the transformer comprises: a bobbin having a winding core for winding a wire; and at least two wires, including a first wire and a second wire respectively wound around the winding core.

[0003] Typically, the first wire and the second wire respectively constitute a first winding portion and a second winding portion wound around the winding core portion except for respective both end portions connected to the terminal electrodes.

[0004] like Fig. 9 As shown, the first wire 1 and the second wire 2 respectively have central conductors 3 and 4 made of a good conductive metal, and insulating coatings 5 ​​and 6 made of an electrically insulating resin covering the circumference of the central conductors 3 and 4. In the first winding portion and the second winding portion, the cross-sections of the first wire 1 and the second wire 2 are circular.

[0005] like Fig. 9 As shown, the first wire 1 and the second wire 2 are wound around the winding core in a state adjacent to each other at the first winding portion and the second winding portion, respectively. In this state, if there is a potential difference between the first wire 1 and the second wire 2, an electrostatic capacitance is generated between the first wire 1 and the second wire 2. In the case of a large electrostatic capacitance, it will have an adverse effect on the electrical characteristics of the common mode choke coil or the transformer.

[0006] For example, Japanese Patent Application Publication No. 2017-537462 (Patent Document 1) describes a structure that reduces electrostatic capacitance by arranging a wall having a tube cross-section shape made of an electrically insulating material between a first wire wound on the inner layer side and a second wire wound on the outer layer side.

[0007] Patent Document 1: Japanese Patent Application No. 2017-537462

[0008] In the structure described in Patent Document 1, the existence of the tube-shaped wall hinders the miniaturization of the coil component. In addition, the tube-shaped wall needs to be prepared as a separate component, which complicates the manufacturing process of the coil component and increases the cost. Summary of the invention

[0009] Therefore, an object of the present invention is to provide a coil component that can solve the above-mentioned problem, that is, can suppress the generation of stray capacitance without requiring an additional component such as a wall in a tube-shaped cross-section.

[0010] The present invention relates to a coil component, which comprises: a winding tube having a winding core; and at least two wires, each of which is wound around the winding core and includes a first wire and a second wire, wherein the first wire and the second wire each have a center conductor and an insulating coating made of an electrically insulating resin covering the circumference of the center conductor.

[0011] The coil component of the present invention is characterized in that the first wire and the second wire respectively have a first winding portion and a second winding portion wound around the winding core in a state adjacent to each other. In order to solve the above technical problem, in at least one of the first winding portion and the second winding portion, the insulating coating has a large diameter portion and a small diameter portion having an outer diameter smaller than the large diameter portion, and the large diameter portion and the small diameter portion are distributed over a plurality of locations along the extension direction of the wire.

[0012] According to the present invention, a large diameter portion and a small diameter portion are mixed in the insulating coating of the wire, thereby forming a gap caused by the difference in radial dimensions between the large diameter portion and the small diameter portion between the first winding portion and the second winding portion. This gap can be filled with air having a low dielectric constant, thereby contributing to reducing the electrostatic capacitance generated between the first winding portion and the second winding portion. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a cross-sectional view showing a schematic structure of a coil component 11 according to the first embodiment of the present invention.

[0014] Figure 2 It is schematically represented in Figure 1 In the coil component 11 shown in the figure, the first winding portion 29 of the first wire 27 and the second winding portion 30 of the second wire 28 are wound around the winding core in a state adjacent to each other, along the Figure 1 A cross-sectional view of line AA.

[0015] Figure 3 It is along Figure 2 2 is a cross-sectional view of a first wound portion 29 of a first wire 27 and a second wound portion 30 of a second wire 28 of a wire BB.

[0016] Figure 4 2 is a diagram for explaining a second embodiment of the present invention, and schematically shows a first winding portion 29 of a first wire 27 and a second winding portion 30 of a second wire 28 wound around a winding core in a state adjacent to each other, and corresponds to Figure 2 sectional view of .

[0017] Figure 5 It is along Figure 4 2 is a cross-sectional view of a first wound portion 29 of a first wire 27 and a second wound portion 30 of a second wire 28 of a line CC.

[0018] Figure 6 2 is a diagram for explaining a third embodiment of the present invention, and is a diagram showing a winding portion 29 of a wire 27. Figure 2 sectional view of .

[0019] Figure 7 FIG. 2 is a diagram for explaining a fourth embodiment of the present invention, and is a diagram showing a winding portion 29 of a wire 27. Figure 2 sectional view of .

[0020] Figure 8 1 is a diagram for explaining a fifth embodiment of the present invention, and is a diagram showing a winding portion 29 of a wire 27. Figure 2 sectional view of .

[0021] Fig. 9 It is a diagram for explaining the background art of the present invention and is a cross-sectional view of a first wound portion of a first wire 1 and a second wound portion of a second wire 2 .

[0022] Description of Reference Numerals

[0023] 11…coil component; 12…bobbin; 13…winding core; 27…first wire; 28…second wire; 29…first winding portion; 30…second winding portion; 31, 32…center conductor; 33, 34…insulating coating; 35, 36…large diameter portion; 37, 38…small diameter portion; 39, 40…gap. DETAILED DESCRIPTION

[0024] Reference Figure 1 A schematic structure of the coil component 11 according to the first embodiment of the present invention will be described.

[0025] The coil component 11 constitutes, for example, a common mode choke coil. The coil component 11 includes a bobbin 12. The bobbin 12 includes a winding core 13, and a first flange 15 and a second flange 16 respectively provided at opposite ends of the winding core 13 in the axial direction. The bobbin 12 is preferably made of ferrite. The bobbin 12 may also be made of a non-conductive material other than ferrite, such as a non-magnetic body such as alumina, a resin such as plastic, or a resin containing ferrite powder or metal magnetic powder.

[0026] The winding core 13 and the first and second flanges 15 and 16 of the bobbin 12 are formed, for example, in a quadrangular prism shape having a quadrangular cross-sectional shape. In addition, the ridges of the winding core 13 and the flanges 15 and 16 of the quadrangular prism shape may be rounded. In addition, the cross-sectional shape of the winding core 13 and the flanges 15 and 16 may be a polygon such as a hexagon, a circle, an ellipse, or a combination thereof, in addition to a quadrangle.

[0027] The first flange portion 15 has a bottom surface 17 facing the mounting substrate when mounted, and a top surface 19 facing in the opposite direction to the bottom surface 17. The second flange portion 16 also has a bottom surface 18 facing the mounting substrate when mounted, and a top surface 20 facing in the opposite direction to the bottom surface 18, similarly to the first flange portion 15.

[0028] Although not shown in detail, the bottom surface 17 of the first flange portion 15 is formed along the same Figure 1 The first terminal electrode 21 and the third terminal electrode 23 are arranged in a direction perpendicular to the paper and spaced apart from each other. Figure 1 The second terminal electrode 22 and the fourth terminal electrode 24 are arranged in a direction perpendicular to the paper and spaced apart from each other. Figure 1 , the first terminal electrode 21 and the second terminal electrode 22 are shown as being formed on the outer surfaces of the first flange portion 15 and the second flange portion 16 , respectively, and the third terminal electrode 23 and the fourth terminal electrode 24 are shown in cross section together with a portion of the first flange portion 15 and the second flange portion 16 .

[0029] The coil component 11 further includes at least two wires respectively wound around the winding core 13. In the present embodiment, the wires include a first wire 27 and a second wire 28. Figure 1 In order to make the distinction between the first wire 27 and the second wire 28 clearer in the drawing, the first wire 27 is shaded. The first wire 27 and the second wire 28 respectively have a first winding portion 29 and a second winding portion 30 wound around the winding core 13. The first wire 27 is wound so that the inner layer is formed by the first winding portion 29, and the second wire 28 is wound so that the outer layer is formed by the second winding portion 30. Although not shown in the figure, both ends of the first wire 27 are connected to the first terminal electrode 21 and the second terminal electrode 22, respectively, and both ends of the second wire 28 are connected to the third terminal electrode 23 and the fourth terminal electrode 24, respectively. These connections are, for example, thermal compression bonding.

[0030] Figure 2 It is along Figure 1 The cross-sectional view of line AA will Figure 1The first winding portion 29 of the first wire 27 and the second winding portion 30 of the second wire 28 wound on the winding core 13 are shown enlarged and schematically. Figure 2 As shown, the first wound portion 29 of the first wire 27 and the second wound portion 30 of the second wire 28 are adjacent to each other. Figure 3 is Figure 2 A further enlarged view is shown along Figure 2 2 is a cross-sectional view of a first wound portion 29 of a first wire 27 and a second wound portion 30 of a second wire 28 of a wire BB.

[0031] Reference Figure 2 and Figure 3 The first wire 27 and the second wire 28 respectively have a central conductor 31 and 32 made of a metal with good conductivity such as copper, silver, or gold, and an insulating coating 33 and 34 made of an electrically insulating resin such as polyurethane, polyamide-imide, or polyester that covers the circumference of the central conductor 31 and 32. In the first winding portion 29 and the second winding portion 30, the cross-section of the central conductor 31 and 32 is circular, and has a substantially constant diameter along the extending direction of the wires 27 and 28.

[0032] On the other hand, the insulating coatings 33 and 34 have radial dimensions that vary along the extending directions of the wires 27 and 28. That is, the insulating coating 33 of the first winding portion 29 on the first wire 27 side has a large diameter portion 35 and a small diameter portion 37 having an outer diameter smaller than the large diameter portion 35. The insulating coating 34 of the second winding portion 30 on the second wire 28 side has a large diameter portion 36 and a small diameter portion 38 having an outer diameter smaller than the large diameter portion 35.

[0033] The large diameter portion 35 and the small diameter portion 37 of the insulating film 33 of the first winding portion 29 are distributed over a plurality of locations along the extending direction of the first wire 27. The large diameter portion 36 and the small diameter portion 38 of the insulating film 34 of the second winding portion 30 are distributed over a plurality of locations along the extending direction of the second wire 28.

[0034] In this embodiment, the large diameter portion 35 and the small diameter portion 37 on the first winding portion 29 are alternately arranged at a constant interval along the extending direction of the first wire 27. Similarly, the large diameter portion 36 and the small diameter portion 38 on the second winding portion 30 are alternately arranged at a constant interval along the extending direction of the second wire 28.

[0035] In addition, regarding the lengths measured in the extending directions of the first wire 27 and the second wire 28 , the large diameter portion 35 and the large diameter portion 36 are equal to each other, and the small diameter portion 37 and the small diameter portion 38 are equal to each other.

[0036] In addition, the arrangement interval between the large diameter portion 35 and the small diameter portion 37 on the first winding portion 29 side is equal to the arrangement interval between the large diameter portion 36 and the small diameter portion 38 on the second winding portion 30 side. In addition, the large diameter portion 35 on the first winding portion 29 side is opposite to the small diameter portion 38 on the second winding portion 30 side, and the small diameter portion 37 on the first winding portion 29 side is opposite to the large diameter portion 36 on the second winding portion 30 side.

[0037] In each of the first winding portion 29 and the second winding portion 30, the thickness of the insulating films 33 and 34 at the large diameter portions 35 and 36 is preferably not more than twice the thickness of the insulating films 33 and 34 at the small diameter portions 37 and 38. In addition, the thickness of the insulating films 33 and 34 at the large diameter portions 35 and 36 is preferably not less than 1.1 times the thickness of the insulating films 33 and 34 at the small diameter portions 37 and 38.

[0038] In addition, in this embodiment, the thickness of the insulating coating 33 at the large diameter portion 35 in the first winding portion 29 is substantially equal to the thickness of the insulating coating 34 at the large diameter portion 36 in the second winding portion 30, and the thickness of the insulating coating 33 at the small diameter portion 37 in the first winding portion 29 is substantially equal to the thickness of the insulating coating 34 at the small diameter portion 38 in the second winding portion 30.

[0039] As described above, according to the present embodiment, the large diameter portions 35 and 36 and the small diameter portions 37 and 38 are mixed in the insulating films 33 and 34, thereby forming a gap 39 caused by the difference in radial dimensions between the large diameter portions 35 and 36 and the small diameter portions 37 and 38 between the first winding portion 29 and the second winding portion 30. The gap 39 is usually filled with air having a low dielectric constant, and thus contributes to reducing the electrostatic capacitance generated between the first winding portion 29 and the second winding portion 30. In the present embodiment, the gap 39 has a size corresponding to the difference in radial dimensions between the large diameter portions 35 and 36 and the small diameter portions 37 and 38.

[0040] In addition, when the cross-sectional shape of the winding core is a polygon such as a quadrilateral, it is preferred that at least one large diameter portion is located on one side of the polygon, or the large diameter portion is located at at least one corner of the polygon. When the cross-sectional shape of the winding core is a circle or an ellipse, it is preferred that at least one large diameter portion is located within a circle.

[0041] In the present embodiment, the thickness varies in two steps as in the large-diameter portions 35 and 36 and the small-diameter portions 37 and 38 , but the thickness may vary in three or more steps.

[0042] Next, refer to Figure 4 and Figure 5 A second embodiment of the present invention will be described. Figure 4is equivalent to Figure 2 A cross-sectional view of Figure 5 is equivalent to Figure 3 Figure. Figure 4 and Figure 5 In, with Figure 2 and Figure 3 Corresponding elements are denoted by the same reference numerals, and duplicate descriptions are omitted.

[0043] In this embodiment, the large diameter portion 35 and the small diameter portion 37 on the first winding portion 29 are alternately arranged at irregular intervals along the extending direction of the first wire 27. Similarly, the large diameter portion 36 and the small diameter portion 38 on the second winding portion 30 are alternately arranged at irregular intervals along the extending direction of the second wire 28.

[0044] Therefore, there is no particular regularity between the large diameter portion 35 and the small diameter portion 37 on the first wound portion 29 side and the large diameter portion 36 and the small diameter portion 38 on the second wound portion 30 side.

[0045] As a result, the large diameter portion 35 on the first winding portion 29 side faces the large diameter portion 36 on the second winding portion 30 side, and also faces the small diameter portion 38 on the second winding portion 30 side. Similarly, the small diameter portion 37 on the first winding portion 29 side faces the large diameter portion 36 on the second winding portion 30 side, and also faces the small diameter portion 38 on the second winding portion 30 side.

[0046] As described above, according to the present embodiment, the large diameter portions 35 and 36 and the small diameter portions 37 and 38 are mixed in the insulating films 33 and 34, and thus the gap 40 caused by the difference in radial dimensions between the large diameter portions 35 and 36 and the small diameter portions 37 and 38 is formed between the first winding portion 29 and the second winding portion 30. In the present embodiment, the gap 40 has a size equivalent to twice the difference in radial dimensions between the large diameter portions 35 and 36 and the small diameter portions 37 and 38 at the largest portion.

[0047] In the first and second embodiments, the first winding portion 29 and the second winding portion 30, which are wound around the winding core 13 in a state adjacent to each other, have the large diameter portions 35 and 36 and the small diameter portions 37 and 38, but only one of the first winding portion and the second winding portion may have the large diameter portion and the small diameter portion. Even in this case, a gap caused by the difference in radial dimensions between the large diameter portion and the small diameter portion can be formed between the first winding portion and the second winding portion.

[0048] In the first and second embodiments, the large diameter portions 35 and 36 have a stepped shape rising from the small diameter portions 37 and 38 in a direction perpendicular to the extending direction of the wires 27 and 28. In other words, the cross section has a quadrilateral shape, but the shape can be changed arbitrarily.

[0049] Figure 6 to Figure 8 1 is a diagram for explaining another embodiment of the present invention, and shows a modified example of the large diameter portion. Figure 6 to Figure 8 , only the winding portion of one of the first winding portion of the first wire and the second winding portion of the second wire, for example, the first winding portion 29 of the first wire 27, which are wound around the winding core in a state adjacent to each other, is shown. Figure 6 to Figure 8 In the figure, the reference numerals associated with the first winding portion 29 of the first wire 27 are the same as those in Figure 2 The same reference numerals are used in the drawings, and repeated descriptions are omitted. Although not shown in the figure, the winding portion of the other wire may have a large diameter portion and a small diameter portion, or may not have them.

[0050] exist Figure 6 In the third embodiment shown, the large diameter portion 35 having a trapezoidal cross section is provided.

[0051] exist Figure 7 In the fourth embodiment shown, the large diameter portion 35 having a triangular cross-section is provided.

[0052] exist Figure 8 In the fifth embodiment shown, the large diameter portion 35 having a semi-elliptical cross section is provided.

[0053] As in the first to fifth embodiments described above, in order to change the radial dimensions of the insulating films 33 and 34 along the extending direction of the wires 27 and 28, a method of changing the amount of the insulating film material applied to the peripheral surface of the center conductors 31 and 32 to form the insulating films 33 and 34, a method of partially irradiating with laser after forming the insulating films 33 and 34 with a uniform thickness, or a method of physically removing a portion of the thickness of the insulating films 33 and 34 using a sharp rotary blade, etc. It is also possible to adopt the method of peeling off a portion of the thickness of the insulating films 33 and 34 by irradiating with laser light in parallel with the step of winding the wires 27 and 28 around the winding core 13.

[0054] As mentioned above, although this invention was demonstrated in connection with the embodiment shown in figure, other various embodiments are realizable within the scope of this invention.

[0055] For example, the insulating coatings 33 and 34 are shown as having the same radial dimension in the circumferential direction. However, even if the radial dimension varies in the circumferential direction, the radial dimension may vary in both the extending direction of the wire and the circumferential direction.

[0056] In addition, in the illustrated embodiment, a multilayer winding is adopted in which the first wire and the second wire are wound around the winding core portion with one side forming an inner layer and the other side forming an outer layer, but a double-wire winding in which the first wire and the second wire are adjacent to each other in the axial direction of the winding core portion may be adopted, or a winding in which the positional relationship between the first wire and the second wire is changed to have a cross structure in a part may be adopted, or a twisted winding in which the first wire and the second wire are wound in a twisted state may be adopted.

[0057] In addition, in the present invention, a large diameter portion and a small diameter portion are mixed in the insulating film of the wire, thereby forming a gap caused by the difference in radial dimensions between the large diameter portion and the small diameter portion between the first winding portion and the second winding portion, so in order to seek the effect of reducing electrostatic capacitance, it is preferred that the above gap is filled with air with a low dielectric constant. However, even if the coil component is impregnated with resin, for example, and the above gap is filled with resin, as long as the relative dielectric constant of the resin is lower than the relative dielectric constant of the insulating film, the effect of reducing electrostatic capacitance can be maintained.

[0058] Furthermore, the above-described embodiment relates to a coil component constituting a common mode choke coil, but may constitute other transformers or the like.

[0059] In addition, the above-mentioned embodiments are merely examples, and some structures may be replaced or combined between different embodiments.

[0060] The embodiments of the present invention are as follows.

[0061] <1> A coil component comprising:

[0062] a bobbin having a winding core; and

[0063] at least two wires are respectively wound around the winding core and include a first wire and a second wire, each having a center conductor and an insulating coating made of an electrically insulating resin covering a circumferential surface of the center conductor,

[0064] The first wire and the second wire respectively have a first winding portion and a second winding portion which are wound around the winding core portion in a state of being adjacent to each other.

[0065] In at least one of the first winding portion and the second winding portion, the insulating coating has a large diameter portion and a small diameter portion having an outer diameter smaller than the large diameter portion, and the large diameter portion and the small diameter portion are distributed over a plurality of locations along an extending direction of the wire.

[0066] <2> According to the coil component described in <1>,

[0067] The large-diameter portions and the small-diameter portions are alternately arranged at regular intervals along an extending direction of the wire rod.

[0068] <3> According to the coil component described in <1>,

[0069] The large-diameter portion and the small-diameter portion are alternately arranged at irregular intervals along the extending direction of the wire rod.

[0070] <4> The coil component according to any one of <1> to <3>,

[0071] The thickness of the insulating film at the large-diameter portion is not more than twice the thickness of the insulating film at the small-diameter portion.

[0072] <5> The coil component according to any one of <1> to <4>,

[0073] In both the first wound portion and the second wound portion, the first wire rod and the second wire rod have the large-diameter portion and the small-diameter portion.

[0074] <6> According to the coil component described in <5>,

[0075] The large-diameter portion on the first winding portion side includes a portion facing the large-diameter portion on the second winding portion side.

[0076] <7> The coil component according to <5> or <6>,

[0077] The large-diameter portion on the first winding portion side includes a portion facing the small-diameter portion on the second winding portion side.

[0078] <8> The coil component according to any one of <1> to <7>,

[0079] The first wire and the second wire are wound around the winding core so that one of them forms an inner layer and the other forms an outer layer.

[0080] <9> The coil component according to any one of <1> to <8>,

[0081] The coil component constitutes a common mode choke coil.

[0082] <10> The coil component according to any one of <1> to <8>,

[0083] The coil assembly constitutes a transformer.

Claims

1. A coil component, wherein: have: a bobbin having a winding core; and at least two wires are respectively wound around the winding core and include a first wire and a second wire, wherein the first wire and the second wire each have a central conductor and an insulating film made of an electrically insulating resin covering a circumference of the central conductor, The first wire and the second wire respectively include a first winding portion and a second winding portion which are wound around the winding core in a state of being adjacent to each other. In at least one of the first winding portion and the second winding portion, the insulating coating has a large diameter portion and a small diameter portion having an outer diameter smaller than the large diameter portion, and the large diameter portion and the small diameter portion are distributed over a plurality of locations along an extending direction of the wire.

2. The coil component according to claim 1, wherein The large-diameter portions and the small-diameter portions are alternately arranged at regular intervals along an extending direction of the wire rod.

3. The coil component according to claim 1, wherein The large-diameter portions and the small-diameter portions are alternately arranged at irregular intervals along the extending direction of the wire.

4. The coil component according to any one of claims 1 to 3, wherein The thickness of the insulating film at the large diameter portion is not more than twice the thickness of the insulating film at the small diameter portion.

5. The coil component according to any one of claims 1 to 4, wherein In both the first winding portion and the second winding portion, the first wire rod and the second wire rod have the large-diameter portion and the small-diameter portion.

6. The coil component according to claim 5, wherein The large-diameter portion on the first winding portion side includes a portion facing the large-diameter portion on the second winding portion side.

7. The coil component according to claim 5 or 6, wherein: The large-diameter portion on the first winding portion side includes a portion facing the small-diameter portion on the second winding portion side.

8. The coil component according to any one of claims 1 to 7, wherein The first wire and the second wire are wound around the winding core so that one of them forms an inner layer and the other forms an outer layer.

9. The coil component according to any one of claims 1 to 8, wherein: The coil component constitutes a common mode choke coil.

10. The coil component according to any one of claims 1 to 8, wherein The coil assembly constitutes a transformer.

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