Coil parts

Abstract

A coil component is provided that can suppress deterioration of mode conversion characteristics while realizing miniaturization and high inductance. The coil component includes a core having a winding core portion, and a coil including a plurality of wires wound around the winding core portion, the coil has a twisted wire portion in which the plurality of wires are twisted together, the stranded wire portion has a bank region including a first layer wound continuously around the winding core portion by a plurality of turns, and a second layer wound continuously from the first layer onto the first layer, the stranded wire portion has a plurality of bank regions along the winding core portion, The bank region closest to one end in the direction along the winding core portion is densely wound, with the number of turns of the second layer being one turn less than the number of turns of the first layer, and all bank regions other than the densely wound bank region are loosely wound, with the number of turns of the second layer being two or more turns less than the number of turns of the first layer.

Description

[Technical Field]

[0001] The present invention relates to a coil component. [Background technology]

[0002] A conventional wire-wound coil component including a wire is described in JP 2014-216525 A (Patent Document 1). This coil component includes a core including a winding core portion, and a coil including two wires wound around the winding core portion, the coil having a twisted wire portion in which the two wires are twisted together, and the twisted wire portion is wound directly around the winding core portion of the core. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-216525 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in conventional coil components, if one tries to make them smaller or to obtain higher inductance, the number of turns of wire relative to the length of the winding core increases, which may result in a lack of room for the length of the winding core.

[0005] In particular, when winding the twisted wire portion around the winding core, gaps are more likely to occur between the turns than when winding two wires around the winding core without twisting them together, and the length of the winding core required to wind the same number of turns becomes longer.

[0006] Therefore, it is expected that it will be difficult to achieve miniaturization and high inductance with a configuration in which the twisted wire portion is wound directly around the winding core portion, that is, wound in one layer.

[0007] To solve this problem, the inventors of the present application considered winding the core in multiple layers, that is, winding another stranded wire section over the stranded wire section that is wound directly around the core. However, they found that depending on the way the stranding is done, the mode conversion characteristics (Scd21, Sdc21, noise removal characteristics) could be significantly degraded.

[0008] Therefore, an object of the present disclosure is to provide a coil component that can suppress deterioration of mode conversion characteristics while realizing miniaturization and high inductance. [Means for solving the problem]

[0009] In order to solve the above problems, a coil component according to one aspect of the present disclosure comprises: a core having a winding core portion; a coil including a plurality of wires wound around the winding core; Equipped with the coil has a twisted wire portion in which the plurality of wires are twisted together, the stranded wire portion has a bank region including a first layer wound continuously around the winding core portion by a plurality of turns, and a second layer wound continuously from the first layer onto the first layer, The bank region is a loosely wound wire with the number of turns of the second layer being two or more turns less than the number of turns of the first layer.

[0010] According to the coil component of the present disclosure, the coil has a bank region including a second layer. Therefore, compared to a configuration in which the twisted wire portion is wound around the winding core portion by one layer, the number of turns of the twisted wire portion can be increased for the same length of the winding core portion, thereby achieving miniaturization or high inductance.

[0011] In addition, the bank region is loosely wound, with the number of turns in the second layer being two or more turns less than the number of turns in the first layer, which reduces the inter-wire capacitance caused by the overlapping of the twisted wire sections and suppresses deterioration of the mode conversion characteristics.

[0012] Therefore, it is possible to suppress deterioration of the mode conversion characteristics while realizing a reduction in size or a high inductance.

[0013] In one embodiment of the coil component, in the loosely wound bank region, the second layer is shifted toward the final turn of the first layer.

[0014] According to the embodiment, the length of the twisted wire portion connecting the first and second layers can be shortened, thereby reducing the inter-wire capacitance generated in the twisted wire portion connecting the first and second layers. In addition, the second layer is located closer to the side of the first layer that is closer in turn ordinal number to the second layer, thereby reducing the combined inter-wire capacitance of the entire twisted wire portion. The final turn of the first layer refers to the turn of the first layer that is wound around the core just before the part that connects the first and second layers. The turn ordinal number indicates the number of turns toward the core counted from one end of the coil, that is, the order of the turns counted from one end of the coil. For example, the first turn toward the core counted from one end of the coil is the first turn, the next turn is the second turn, and if i is an integer, the ith turn counted from one end of the coil is expressed as the ith turn.

[0015] In one embodiment of the coil component, the second layer includes a portion wound on the final turn of the first layer.

[0016] According to the embodiment, the length of the twisted wire portion connecting the first layer and the second layer can be shortened, and the inter-wire capacitance generated in the twisted wire portion connecting the first layer and the second layer can be reduced. In addition, because a part of the second layer is wound on the final turn of the first layer that is closest in turn ordinal number to the second layer, the combined inter-wire capacitance of the entire twisted wire portion can be reduced.

[0017] In one embodiment of the coil component, the number of turns in the top layer in the loosely wound bank region is one turn.

[0018] According to the embodiment, the line capacitance occurring on the uppermost layer can be further reduced.

[0019] In one embodiment of the coil component, the number of turns of the first layer in the loosely wound bank region is 5 turns or less.

[0020] According to the embodiment, by setting the number of turns in the first layer to 5 or less, the difference in turn ordinal numbers between the first and second layers can be reduced, thereby further reducing the combined inter-wire capacitance of the entire twisted wire section.

[0021] In one embodiment of the coil component, the stranded wire portion has a plurality of bank regions including the loosely wound bank region along the winding core portion.

[0022] According to the above embodiment, by having multiple bank regions, the number of turns in the stranded wire portion can be increased for the same length of the winding core, compared to a configuration in which the stranded wire portion is wound in one layer around the winding core, thereby achieving further miniaturization or higher inductance. Furthermore, since the total number of turns is divided among multiple bank regions, the number of turns in the first layer in each bank region is reduced. This reduces the difference in turn ordinal numbers between the first and second layers, thereby further reducing the combined inter-wire capacitance of the entire stranded wire portion.

[0023] In one embodiment of the coil component, at least two of the plurality of bank regions have the same shape.

[0024] Here, the same shape means that the winding pattern of the stranded wire portion in the bank region (the number of turns in each layer of the stranded wire portion, the winding position of each layer of the stranded wire portion) is the same.

[0025] According to the embodiment, it is possible to reduce the directivity occurring in the capacitance between a plurality of wires.

[0026] In one embodiment of the coil component, all of the plurality of bank regions except for both ends in the direction along the winding core portion have the same shape.

[0027] According to the embodiment, the directivity occurring in the capacitance between a plurality of wires can be further reduced.

[0028] Moreover, in one embodiment of the coil component, the number of layers of each of the plurality of bank regions is two; In all bank regions except for the two ends, the number of turns in the first layer is four, and the number of turns in the second layer is two.

[0029] According to the embodiment, it is possible to achieve a balance between reducing the inter-line capacitance and preventing a decrease in manufacturing efficiency.

[0030] Moreover, in one embodiment of the coil component, The core includes a first flange portion provided at a first end of the winding core portion, a second flange portion provided at a second end of the winding core portion, a first electrode portion and a second electrode portion provided at the first flange portion, and a third electrode portion and a fourth electrode portion provided at the second flange portion, and the coil includes a first wire electrically connected to the first electrode portion and the third electrode portion, and a second wire electrically connected to the second electrode portion and the fourth electrode portion, and the first wire and the second wire are wound in the same direction around the winding core portion.

[0031] According to the embodiment, a common mode choke coil can be configured in which the first electrode portion and the second electrode portion serve as one of the input terminal and the output terminal, and the third electrode portion and the fourth electrode portion serve as the other of the input terminal and the output terminal.

[0032] In addition, in one embodiment of the coil component, the coil has a winding region wound around the winding core portion and a non-winding region separated from the winding core portion and connected to the first electrode portion, the second electrode portion, the third electrode portion, or the fourth electrode portion, and in a portion of the winding region adjacent to the non-winding region, the first wire and the second wire are untwisted from each other.

[0033] According to the above embodiment, the first wire and the second wire are untwisted from each other in the portion of the winding area adjacent to the non-winding area, so that it is possible to space the first wire and the second wire apart at the winding start or end where stress is applied to the wires, thereby reducing the occurrence of wire damage such as wire breakage or short circuits between wires.

[0034] In addition, in one embodiment of the coil component, the coil has a winding region wound around the winding core portion and a non-winding region separated from the winding core portion and connected to the first electrode portion, the second electrode portion, the third electrode portion, or the fourth electrode portion, and a portion of the non-winding region adjacent to the winding region is a twisted wire portion.

[0035] According to the above embodiment, the portion of the non-wound region adjacent to the wound region is a twisted wire portion, which can further reduce the difference in line length between the first wire and the second wire and the imbalance in the inter-wire capacitance between the first wire and the second wire, thereby reducing the deterioration of the mode conversion characteristics.

[0036] In one embodiment of the coil component, the non-winding region continues from the twisted wire portion and has a non-twisted wire portion in which the first wire and the second wire are untwisted, and in the non-twisted wire portion, the length of the first wire and the length of the second wire are the same.

[0037] According to the embodiment, the difference in line length between the first wire and the second wire and the imbalance in the inter-wire capacitance between the first wire and the second wire can be further reduced, and the deterioration of the mode conversion characteristics can be further reduced.

[0038] In one embodiment of the coil component, the number of twists per turn of the twisted wire portion is not an integer.

[0039] According to the above embodiment, the number of twists per turn of the twisted wire section is not an integer, and therefore the positional relationship of the multiple wires in each turn of the twisted wire section is not fixed, thereby reducing imbalances in the inter-wire capacitance of the twisted wire section and the capacitance between the mounting board and the wires. The number of twists in a twisted wire section is defined as one when the relative positions of the twisted wires rotate 360°. For example, when two wires rotate 180°, i.e., when the two wires exactly switch places, the number of twists is defined as 0.5, and when the relative positions of the wires rotate another 180°, i.e., when the relative positions of the two wires return to their original position, the number of twists is defined as one.

[0040] In one embodiment of the coil component, the number of twists per turn of the stranded wire portion is n1 / n2 (n2 is a prime number).

[0041] According to the above embodiment, the spacing between turns of the twisted wire section where the positional relationship between multiple wires is the same is wider, and the imbalance in the inter-wire capacitance of the twisted wire section and the capacitance between the mounting board and the wires can be further reduced.

[0042] In one embodiment of the coil component, the stranded wire portion has a reversal portion where the twisting direction is reversed.

[0043] According to the embodiment, the overlap of twists in the twisted wire section can be reduced, thereby improving the reliability of the wire. Note that the twist direction of the twisted wire section refers to the rotation direction of the multiple wires twisted together, and is expressed as either a Z twist or an S twist.

[0044] In one embodiment of the coil component, the number of inversion portions of the stranded wire portion is odd.

[0045] According to the embodiment, when manufacturing a coil component, the number of times the twisted wire portions appear in the twisting directions when winding the twisted wire portions around the winding core portion is equal, that is, the number of Z-twisted twisted wire portions is equal to the number of S-twisted twisted wire portions, thereby reducing the occurrence of kinks in the wire.

[0046] In one embodiment of the coil component, the stranded wire portion has a plurality of inverted portions, and there are locations where the intervals between adjacent inverted portions are equal.

[0047] According to the above embodiment, it is possible to reduce the imbalance in the capacitance between the twisted wires and the capacitance between the mounting board and the wires. Moreover, in one embodiment of the coil component, a core having a winding core portion; a coil including a plurality of wires wound around the winding core; Equipped with the coil has a twisted wire portion in which the plurality of wires are twisted together, the stranded wire portion has a plurality of bank regions each including a first layer wound continuously around the winding core portion by a plurality of turns, and a second layer wound continuously from the first layer onto the first layer, the bank region is a loosely wound wire in which the number of turns of the second layer is two or more turns less than the number of turns of the first layer; the twisted wire portion has a reversal portion in which the twist direction is reversed between each of the plurality of bank regions, The stranded wire portion has a plurality of inverted portions, and the intervals between adjacent inverted portions are equal. [Effects of the Invention]

[0048] According to the coil component of one aspect of the present disclosure, it is possible to suppress deterioration of mode conversion characteristics while realizing miniaturization or high inductance. [Brief explanation of the drawings]

[0049] [Figure 1] 1 is a perspective view showing a first embodiment of a coil component as viewed from the bottom side. FIG. [Figure 2A] FIG. 1 is an enlarged view of a Z-twisted wire portion. [Figure 2B] This is an enlarged view of the S-twisted wire section. [Figure 3] FIG. 2 is a simplified cross-sectional view of a coil component. [Figure 4] FIG. 3 is a simplified cross-sectional view of a first flange portion of the coil component. [Figure 5] FIG. 3 is a simplified cross-sectional view showing a preferred embodiment of the first flange portion. [Figure 6] FIG. 3 is a simplified cross-sectional view showing a preferred embodiment of the first flange portion. [Figure 7]10A to 10C are explanatory diagrams illustrating a method for forming a stranded wire portion. [Figure 8] FIG. 2 is a simplified diagram showing a packaging form of the coil component. [Figure 9] FIG. 4 is a simplified cross-sectional view showing a second embodiment of the coil component. [Figure 10] FIG. 10 is a simplified bottom view showing a third embodiment of the coil component. [Figure 11A] FIG. 2 is a simplified cross-sectional view showing a bank region in Example 1. [Figure 11B] FIG. 10 is a simplified cross-sectional view showing a bank region of Example 2. [Figure 11C] FIG. 10 is a simplified cross-sectional view showing a bank region of Example 3. [Figure 12A] FIG. 10 is a simplified cross-sectional view showing a bank region of Comparative Example 1. [Figure 12B] FIG. 10 is a simplified cross-sectional view showing a bank region of Comparative Example 2. DETAILED DESCRIPTION OF THE INVENTION

[0050] Hereinafter, one aspect of the present disclosure will be described in detail with reference to the illustrated embodiment.

[0051] (First embodiment) Fig. 1 is a perspective view from the bottom side showing a first embodiment of a coil component. As shown in Fig. 1, the coil component 1 includes a core 10, a coil 20 wound around the core 10, a first electrode portion 31, a second electrode portion 32, a third electrode portion 33, and a fourth electrode portion 34 provided on the core 10 and electrically connected to the coil 20, which serve as external terminals, and a plate member 15 attached to the core 10.

[0052] Core 10 has a winding core 13 that extends in a fixed direction and around which coil 20 is wound, a first flange 11 that is provided at a first end of winding core 13 in the extension direction and that protrudes in a direction perpendicular to said direction, and a second flange 12 that is provided at a second end of winding core 13 in the extension direction and that protrudes in a direction perpendicular to said direction. Core 10 is preferably made of a magnetic material such as a sintered ferrite or a molded body of resin containing magnetic powder, but may also be made of a non-magnetic material such as alumina or resin. In the following description, the bottom surface of core 10 will be referred to as the surface that is mounted on a mounting board, and the surface of core 10 opposite the bottom surface will be referred to as the top surface of core 10.

[0053] The first flange portion 11 has an inner surface 111 facing the winding core portion 13, an outer surface 112 facing the opposite side to the inner surface 111, a lower surface 113 connecting the inner surface 111 and the outer surface 112, an upper surface 114 facing the opposite side to the lower surface 113, and two side surfaces 115 connecting the inner surface 111 and the outer surface 112 and connecting the lower surface 113 and the upper surface 114. Similarly, the second flange portion 12 has an inner surface 121 facing the winding core portion 13, an outer surface 122 facing the opposite side to the inner surface 121, a lower surface 123, an upper surface 124, and two side surfaces 125. The lower surface 123, the upper surface 124, and the side surfaces 125 of the second flange portion 12 face in the same directions as the lower surface 113, the upper surface 114, and the side surfaces 115 of the first flange portion 11, respectively. The lower and upper surfaces are for illustrative purposes only and do not necessarily correspond to the upper and lower sides in the vertical direction.

[0054] Plate member 15 is attached to upper surface 114 of first flange 11 and upper surface 124 of second flange 12 with an adhesive. The material of plate member 15 is, for example, the same as that of core 10. When core 10 and plate member 15 are both made of magnetic materials, they form a closed magnetic circuit, improving the efficiency of obtaining inductance.

[0055] The first flange 11 has two legs on the underside 113, one of which is provided with a first electrode 31 and the other with a second electrode 32. The second flange 12 has two legs on the underside 123, one of which is provided with the first electrode 31 and the other with a third electrode 33. The other of which is provided with the second electrode 32 and the other with a fourth electrode 34. As shown in FIG. 1 , the undersides 113 and 123 refer to the areas extending from the undersides of the legs through the sloped crotch area between the legs to include the underside of the crotch area. Hereinafter, the first electrode 31, the second electrode 32, the third electrode 33, and the fourth electrode 34 may be collectively referred to as electrodes 31 to 34.

[0056] The coil 20 includes a first wire 21 and a second wire 22 wound around the winding core 13. That is, the coil axis of the coil 20 coincides with the extension direction of the winding core. The first wire 21 and the second wire 22 are insulating coated conductors in which a conductor made of a metal such as copper is covered with a coating made of a resin such as polyurethane or polyamideimide. One end of the first wire 21 is electrically connected to the first electrode 31 and the other end is electrically connected to the third electrode 33. One end of the second wire 22 is electrically connected to the second electrode 32 and the other end is electrically connected to the fourth electrode 34. The first wire 21 and the second wire 22 are connected to the electrodes 31 to 34 by, for example, thermocompression bonding, brazing, welding, or the like.

[0057] The first wire 21 and the second wire 22 are wound in the same direction around the winding core 13. As a result, in the coil device 1, when an opposite-phase signal, such as a differential signal, is input to the first wire 21 and the second wire 22, the magnetic fluxes generated by the first wire 21 and the second wire 22 cancel each other out, weakening their function as inductors and allowing the signal to pass. On the other hand, when an in-phase signal, such as external noise, is input to the first wire 21 and the second wire 22, the magnetic fluxes generated by the first wire 21 and the second wire 22 reinforce each other, strengthening their function as inductors and blocking the passage of the noise. Therefore, the coil device 1 functions as a common-mode choke coil that reduces the passage loss of differential-mode signals, such as differential signals, while attenuating common-mode signals, such as external noise.

[0058] When coil component 1 is mounted on a mounting board, the lower surfaces of first flange portion 11 and second flange portion 12 face the mounting board. At this time, the direction in which winding core portion 13 extends from the first end to the second end is parallel to the main surface of the mounting board. In other words, coil component 1 is a horizontally wound type in which the coil axes of first wire 21 and second wire 22 are parallel to the mounting board.

[0059] (Detailed configuration of coil 20) The coil 20 has a winding region Z1 wound around the winding core 13, and a non-winding region Z2 that is not wound around the winding core 13. More specifically, the non-winding regions Z2 are located on both sides of the winding region Z1, and are regions that are separated from the winding core 13 and connected to the electrode portions 31 to 34.

[0060] The coil 20 has a twisted wire portion 25 in the winding region Z1. FIGS. 2A and 2B are enlarged views of the twisted wire portion 25. FIG. 2A shows a Z-twisted twisted wire portion 25a, and FIG. 2B shows an S-twisted twisted wire portion 25b. The twisting direction of the Z-twisted twisted wire portion 25a is opposite to that of the S-twisted twisted wire portion 25b. As shown in FIGS. 2A and 2B, the twisted wire portion 25 is a portion where the first wire 21 and the second wire 22 are twisted together. In the twisted wire portion 25, the relative differences between the two wires (such as line length and stray capacitance imbalance) are reduced. This reduces mode conversion output, such as when a differential mode signal is converted into a common mode signal and output within the coil device 1, or vice versa, thereby improving the mode conversion characteristics. 2A and 2B, the first wire 21 and the second wire 22 are twisted together in close contact, but there may be gaps between them in some places, or they may be twisted together with gaps remaining between them overall. In the coil device 1, the winding region Z1 of the coil 20 is almost entirely the twisted wire portion 25. The twist direction of the twisted wire portion 25 may be Z twist or S twist, or may be a mixture of Z twist and S twist, as described below.

[0061] FIG. 3 is a simplified cross-sectional view of the coil device 1. FIG. 3 is a diagram showing a portion of a cross-section of the coil 20 and the winding core 13, taken along the direction in which the winding core 13 extends, passing through the center of the winding core 13 from the first end 131 to the second end 132 of the winding core 13. For simplification, FIG. 3 shows the stranded wire portion 25 as a single wire, and its cross-section is represented as a single circle. Also, in FIG. 3, the ordinal numbers of the turns of the coil 20 counted from the first end 131 of the winding core 13 are indicated by numbers. That is, in the winding region Z1 of the coil 20, the stranded wire portion 25 is wound from the first end 131 to the second end 132 of the winding core 13, a total of 28 turns, from the 1st turn to the 28th turn.

[0062] 3, the stranded wire portion 25 of the coil 20 has five bank regions B1, B2, B3, B4, and B5, including a first layer wound continuously around the winding core 13 with multiple turns, and a second layer wound continuously from the first layer onto the first layer. The first bank region B1, the second bank region B2, the third bank region B3, the fourth bank region B4, and the fifth bank region B5 are arranged in order from the first end 131 toward the second end 132 of the winding core 13, with adjacent bank regions spaced apart. However, the first bank region B1, the second bank region B2, the third bank region B3, the fourth bank region B4, and the fifth bank region B5 may be closely adjacent to each other without any gaps. In the following, when describing the first bank region B1, the second bank region B2, the third bank region B3, the fourth bank region B4, and the fifth bank region B5 collectively, they may be referred to as the first to fifth bank regions B1 to B5.

[0063] The first layers of the first to fifth bank regions B1 to B5 are each wound directly around the winding core 13, and the second layer is wound directly on the first layer. Specifically, in the first bank region B1, the first layer is made up of four turns, the first to fourth turns, wound continuously around the winding core 13, and the second layer is made up of one turn, the fifth turn, which is continuous from the fourth turn of the first layer and wound over the third and fourth turns of the first layer. In the second bank region B2, the first layer is made up of four turns, the sixth to ninth turns, which are wound continuously around the winding core 13, and the second layer is made up of two turns, the tenth and eleventh turns, which are continuous from the ninth turn of the first layer and wound continuously from above the seventh turn to above the ninth turn of the first layer. In the third bank region B3, the first layer is composed of four turns, 12 to 15, wound continuously around the winding core 13, and the second layer is composed of two turns, 16 to 17, continuing from the 15th turn of the first layer and wound continuously from above the 13th turn of the first layer to above the 15th turn. In the fourth bank region B4, the first layer is composed of four turns, 18 to 21, wound continuously around the winding core 13, and the second layer is composed of two turns, 22 to 23, continuing from the 21st turn of the first layer and wound continuously from above the 19th turn of the first layer to above the 21st turn. In the fifth bank region B5, the first layer is composed of three turns, from the 24th turn to the 26th turn, wound continuously around the winding core portion 13, and the second layer is composed of two turns, from the 27th turn to the 28th turn, wound continuously from the 26th turn of the first layer to above the 24th turn to above the 26th turn of the first layer.

[0064] As described above, in the coil device 1, the first to fourth bank regions B1 to B4 have a loosely wound upper layer (second layer) with two or more turns fewer turns than the lower layer (first layer) immediately below the upper layer. Specifically, in the first bank region B1, the number of turns in the first layer is four, and the number of turns in the second layer is one. In the second, third, and fourth bank regions B2, B3, and B4, the number of turns in the first layer is four, and the number of turns in the second layer is two. In the fifth bank region B5, the number of turns in the first layer is three, and the number of turns in the second layer is two, which is one turn fewer than the number of turns in the first layer.

[0065] According to the coil component 1, the coil 20 has bank regions B1 to B5 including the second layer, and therefore, compared to a configuration in which the stranded wire portion 25 is wound around the winding core portion 13 in one layer, the number of turns of the stranded wire portion 25 can be increased for the same length of the winding core portion 13, thereby achieving miniaturization or high inductance.

[0066] Furthermore, the first to fourth bank regions B1 to B4 are loosely wound, with the number of turns in the second layer being two or more turns less than the number of turns in the first layer, which reduces the inter-wire capacitance caused by the overlap of the twisted wire portions 25 and suppresses deterioration of the mode conversion characteristics.

[0067] Therefore, it is possible to suppress deterioration of the mode conversion characteristics while realizing a reduction in size or a high inductance. Note that, from the viewpoint of miniaturization or high inductance, it is usually desirable to wind the second layer with as many turns as possible to improve the winding efficiency of the coil 20 around the winding core portion 13. Furthermore, in reality, to ensure the stability of the wound shape of the first wire 21 and the second wire 22, the second layer is wound onto the depressions formed between adjacent turns of the first layer, as shown in FIG. 3. Therefore, when the second layer is wound as many times as possible within the feasible range, the second layer will be tightly wound, with one turn less than the first layer, as in the fifth bank region B5. On the other hand, in coil device 1, unlike the above idea, the first to fourth bank regions B1 to B4 are loosely wound, with the number of turns in the second layer being two or more turns less than the number of turns in the first layer. In other words, the configuration of coil device 1 was first conceived based on the new discovery by the present inventors that useful characteristics can be obtained by reducing the inter-wire capacitance generated by overlapping of twisted wire portions 25 and suppressing deterioration of mode conversion characteristics, even if it means somewhat sacrificing the winding efficiency of coil 20 around winding core portion 13.

[0068] Furthermore, in the coil device 1, as shown in FIG. 3 , in the first to fourth bank regions B1 to B4, the second layer is shifted toward the final turn of the first layer. Specifically, in the first to fourth bank regions B1 to B4, the second layer is shifted toward the final turn of the first layer, i.e., the turn of the first layer wound around the winding core immediately before the portion connecting the first and second layers: the fourth turn of the first bank region B1, the ninth turn of the second bank region B2, the fifteenth turn of the third bank region B3, and the twenty-first turn of the fourth bank region B4. This shortens the length of the stranded wire portion 25 connecting the first and second layers, thereby reducing the inter-wire capacitance generated in the stranded wire portion 25 connecting the first and second layers. Furthermore, because the second layer is closer to the side of the first layer that is closer in turn ordinal number to the second layer, the combined inter-wire capacitance of the entire stranded wire portion 25 can be reduced.

[0069] In particular, in the coil device 1, in the first to fourth bank regions B1 to B4, the second layer includes a portion wound on the final turn of the first layer. Specifically, in the first to fourth bank regions B1, B2, B3, and B4, the second layer includes the fifth turn wound on the fourth turn, the eleventh turn wound on the ninth turn, the seventeenth turn wound on the fifteenth turn, and the twenty-third turn wound on the twenty-first turn. This allows the length of the stranded wire portion 25 connecting the first and second layers to be shortened, thereby further reducing the inter-wire capacitance generated in the stranded wire portion 25 connecting the first and second layers. Furthermore, because a portion of the second layer is wound on the final turn of the first layer that is closest in turn ordinal number to the second layer, the combined inter-wire capacitance of the entire stranded wire portion 25 can be further reduced.

[0070] Furthermore, in the coil component 1, the number of turns in the second layer, which is the uppermost layer, in the first bank region B1 is 1. This allows for a further reduction in the inter-line capacitance occurring in the uppermost layer.

[0071] Furthermore, in coil device 1, the number of turns in the first layer in the first to fourth bank regions B1 to B4 is 5 or less. By setting the number of turns in the first layer to 5 or less, the difference in turn ordinal numbers between the first and second layers can be reduced, and therefore the overall combined inter-wire capacitance of twisted wire portion 25 can be further reduced.

[0072] Furthermore, in the coil device 1, the stranded wire portion 25 has multiple bank regions B1 to B5, including first to fourth bank regions B1 to B4, along the winding core 13. By having multiple bank regions B1 to B5, the number of turns in the stranded wire portion 25 can be increased for the same length of the winding core 13 compared to a configuration in which the stranded wire portion 25 is wound in one layer around the winding core 13, thereby achieving further miniaturization or higher inductance. Furthermore, because the total number of turns is divided among the multiple bank regions B1 to B5, the number of turns in the first layer in each bank region is reduced. This reduces the difference in turn ordinal numbers between the first and second layers, thereby further reducing the overall combined inter-wire capacitance of the stranded wire portion 25.

[0073] Furthermore, in the coil device 1, the second to fourth bank regions B2 to B4, excluding the first and fifth bank regions B1 and B5 at both ends, have the same shape. This further reduces the directionality that occurs in the capacitance between the first wire 21 and the second wire 22. If at least two of the multiple bank regions have the same shape, the directionality that occurs in the capacitance between the first wire and the second wire can be reduced.

[0074] In the coil device 1, the number of layers in each of the first to fifth bank regions B1 to B5 is two, and in the second to fourth bank regions excluding the first and fifth bank regions B1 and B5 at both ends, the number of turns in the first layer is four and the number of turns in the second layer is two. This makes it possible to achieve a balance between reducing inter-wire capacitance and preventing a decrease in manufacturing efficiency.

[0075] Furthermore, in the coil device 1, the first wire 21 and the second wire 22 are untwisted from each other in the portion of the winding region Z1 of the coil 20 adjacent to the non-winding region Z2. This allows for a gap between the first wire 21 and the second wire 22 at the winding start or winding end where stress is applied to the first wire 21 and the second wire 22, thereby reducing the occurrence of wire breakage such as wire breakage or short circuit between the wires.

[0076] Furthermore, in the coil device 1, the stranded wire portion 25 preferably has a reversal portion where the twist direction is reversed, thereby reducing overlapping of twists in the stranded wire portion 25 and improving wire reliability. Furthermore, the stranded wire portion 25 preferably has multiple reversal portions, with adjacent reversal portions preferably spaced equally apart. This reduces imbalances in the inter-wire capacitance of the stranded wire portion 25 and the capacitance between the mounting board and the wire. Specifically, the stranded wire portion 25 may have an even number of reversal portions between the first to fifth bank regions B1 to B5. In this case, the intervals between adjacent reversal portions are equal, with each having approximately six turns. Note that, as described above, the "interval between adjacent reversal portions" refers to the number of turns in the stranded wire portion 25.

[0077] In coil device 1, the number of twists per turn of twisted wire portion 25 is an integer. As a result, twisted wire portion 25 rotates a multiple of 360° per turn, so the state of twisted wire portion 25 (the number and positions of twist nodes and antinodes, the positional relationship between wires, etc.) is the same for each turn, resulting in a stable winding shape. Furthermore, the number of twists per turn of twisted wire portion 25 is, for example, four, but is not limited to this and may be one to three, or five or more.

[0078] The number of reversal sections in the twisted wire section 25 may be odd. In this case, when the coil component 1 is manufactured, the twisted wire sections 25 will appear in the same twisting direction the same number of times when the twisted wire sections 25 are wound around the winding core section 13. In other words, the number of Z-twisted twisted wire sections 25 will be equal to the number of S-twisted twisted wire sections 25. This reduces the occurrence of kinks in the first wire 21 and the second wire 22.

[0079] (Detailed configuration of electrode parts 31 to 34) 1 and 4, the first electrode unit 31 has a lower-surface-side base electrode 311 provided on the lower surface 113 and an outer-surface-side base electrode 312 provided on the outer surface 112. The outer-surface-side base electrode 312 has a shape that extends from an end of the lower-surface-side base electrode 311 on the outer surface 112 side onto the outer surface 112.

[0080] Specifically, the lower-surface-side base electrode 311 is provided on one of the legs so as to cover the entire lower surface portion of one of the legs on the lower surface 113, as well as the surrounding inner surface 111, outer surface 112, and part of the side surface 115 on the lower surface 113 side. The outer-surface-side base electrode 312 overlaps the end portion of the lower-surface-side base electrode 311 on the outer surface 112 side, and extends from above that end portion toward the upper surface 114 to approximately the middle of the outer surface 112. In other words, the outer-surface-side base electrode 312 extends from approximately the middle of the outer surface 112 of the first flange 11 toward the lower surface 113, and rides onto the end portion of the lower-surface-side base electrode 311 on the outer surface 112 side.

[0081] The coil component 1 has, in addition to the bottom-side base electrode 311 on the bottom surface 113, a separate outer-side base electrode 312 extending from above the bottom-side base electrode 311 onto the outer surface 112. This allows the mounting solder to wet from the bottom surface 113 along the outer surface 112 during mounting, forming a fillet, thereby improving the adhesive strength between the coil component 1 and the mounting board. In particular, if the coil component 1 is made smaller, the amount of mounting solder is reduced, but the fillet can be formed, thereby improving the adhesive strength between the coil component 1 and the mounting board. Furthermore, this embodiment can be realized by adding the outer-side base electrode 312 of this embodiment to the conventional bottom-side base electrode 311. This allows existing equipment to be reused, reducing the additional burden associated with manufacturing the coil component 1. Furthermore, the bottom-side base electrode 311 and the outer-side base electrode 312 can be designed and manufactured independently, improving design flexibility and ease of manufacturing. Therefore, the coil device 1 has a configuration that is suitable for miniaturization, low cost, has a high degree of design freedom, and is easy to manufacture in order to improve the fixing strength.

[0082] In the coil device 1, the coil 20 has a twisted wire portion 25 in which the first wire 21 and the second wire 22 are twisted together. In this case, the configuration of the first electrode portion 31 is more effective. That is, when the twisted wire portion 25 is wound around the winding core 13, gaps are more likely to occur between the turns than when the first wire 21 and the second wire 22 are wound around the winding core 13 without twisting them together, and the length of the winding core 13 required to wind the same number of turns is longer. Therefore, when the coil 20 has the twisted wire portion 25, the lengths of the first flange 11 and the second flange 12 are sacrificed to ensure the length of the winding core 13, and the areas of the electrode portions 31 to 34 also tend to be smaller, so the effect of improving the fixing strength is effective.

[0083] In the coil component 1, the lower surface side base electrode 311 is a sintered body, and the outer surface side base electrode 312 is a metal film. The lower surface side base electrode 311 is a sintered body formed by baking a conductive paste such as Ag glass paste applied by a dip method. The outer surface side base electrode 312 is a metal film formed by sputtering, for example.

[0084] The lower surface side base electrode 311 is a sintered body, which ensures the strength and impact resistance of the lower surface side base electrode 311 itself, and also ensures the adhesive strength between the lower surface side base electrode 311 and the first flange portion 11. On the other hand, the outer surface side base electrode 312 is a metal film, which can be made thinner, thereby reducing the impact on the mounting area on the mounting board.

[0085] Preferably, the lower surface side base electrode 311 contains glass and Ag. This can further ensure the strength and impact resistance of the lower surface side base electrode 311 itself, and can also further ensure the adhesive strength between the lower surface side base electrode 311 and the first flange portion 11.

[0086] Preferably, the outer surface side base electrode 312 includes a NiCu layer. This ensures high toughness even when the outer surface side base electrode 312 is thin, reduces the impact on the mounting area, and improves thermal shock resistance. Note that the outer surface side base electrode 312 preferably includes a NiCr layer on the first flange portion 11 below the NiCu layer, i.e., preferably includes a NiCu layer covering the NiCr layer. This improves adhesion between the outer surface side base electrode 312 and the first flange portion 11 due to the underlying NiCr layer.

[0087] Preferably, the first electrode portion 31 has a metal coating 313, as shown by the imaginary line in Fig. 4. The metal coating 313 covers the lower surface side base electrode 311 and the outer surface side base electrode 312. This integrates the lower surface side base electrode 311 and the outer surface side base electrode 312 with the metal coating 313, improving mounting reliability. Furthermore, if the outer surface side base electrode 312 includes an upper NiCu layer, the upper NiCu layer improves adhesion between the outer surface side base electrode 312 and the metal coating 313.

[0088] Preferably, the metal coating 313 includes a Ni layer and a Sn layer. This improves the solder wettability of the first electrode portion 31 and the corrosion resistance that suppresses the elution of the first wire 21 and the base electrodes 311, 312 into the mounting solder during mounting. In this case, the metal coating 313 preferably further includes a Cu layer. This reduces stress generated in the first electrode portion 31 and further improves the corrosion resistance.

[0089] In this case, it is preferable that the Cu layer, Ni layer, and Sn layer are arranged in this order from the inside to the outside. This reduces stress generated in the first electrode portion 31 and improves solder wettability and corrosion resistance. More specifically, the Sn layer arranged as the outermost layer improves wettability of the mounting solder during mounting and improves connectivity of the first wire 21 to the first electrode portion 31. The Ni layer arranged between the Sn layer and the base electrodes 311 and 312 reduces elution of the base electrodes 311 and 312 into the mounting solder during mounting. The Cu layer arranged below the Ni layer serves as a relatively soft buffer layer below the relatively hard Ni layer, reducing stress generated in the first electrode portion 31. The Cu layer dissolves into the mounting solder instead of the base electrodes 311 and 312, thereby improving corrosion resistance. Furthermore, the Cu layer is not limited to being below the Ni layer (between the Ni layer and the base electrodes 311 and 312) and may be, for example, above the Ni layer (between the Ni layer and the Sn layer). As a result, the Cu layer dissolves into the mounting solder instead of the first wires 21, and the corrosion resistance of the first wires 21 improves.

[0090] However, the metal coating 313 is not limited to the above configuration, and may have a configuration in which the outermost layer of the metal coating 313 includes a Pd layer or an Au layer. This improves the solder wettability and corrosion resistance of the first electrode portion 31. This also makes it possible to eliminate either or both of the Cu layer and the Sn layer, thereby making the metal coating 313 thinner.

[0091] While the configuration of the first electrode portion 31 has been described above, in the coil device 1, the second electrode portion 32, the third electrode portion 33, and the fourth electrode portion 34 each have the same configuration as the first electrode portion 31. Accordingly, since the second electrode portion 32, the third electrode portion 33, and the fourth electrode portion 34 each have the same configuration as the first electrode portion 31, the adhesive strength between the coil device and the mounting board is further improved, and the design freedom and ease of manufacturing are further improved. However, the configuration is not limited to the above, and any two or three of the electrode portions 31 to 34 may have the same configuration. It is sufficient that at least one of the electrode portions 31 to 34 satisfies the above-described configuration.

[0092] (Detailed configuration of the first flange portion 11 and the second flange portion 12) As shown in FIG. 5, the first flange 11 preferably has a first chamfered portion 116 between the top surface 114 and the outer surface 112, and second chamfered portions 117 between the top surface 114 and the two side surfaces 115. The first and second chamfered portions 116, 117 are chamfered into an upwardly convex curved shape. With this, when the plate member 15 is bonded to the top surface 114 of the first flange 11 and the top surface 124 of the second flange 12, the first and second chamfered portions 116, 117 of the first flange 11 provide areas for the adhesive to collect, making it less likely for the adhesive to leak toward the outer surface 112 or the side surfaces 115 of the first flange 11. The first and second chamfered portions 116, 117 may also be chamfered into a downwardly convex curved shape or a flat shape.

[0093] Preferably, the first flange 11 has a ridge 118 between the inner surface 111 and the upper surface 114. The ridge 118 is not chamfered. When the plate member 15 is bonded to the upper surface 114 of the first flange 11 and the upper surface 124 of the second flange 12, the connection area with the plate member 15 is increased at the end of the upper surface 114 on the inner surface 111 side of the first flange 11, where magnetic flux tends to concentrate, and the magnetic path length is shortened, thereby suppressing a decrease in inductance. Instead of the ridge 118, a small chamfered portion having a width smaller than the first and second chamfered portions 116, 117 may be provided between the inner surface 111 and the upper surface 114. This also shortens the magnetic path length and suppresses a decrease in inductance, similar to the ridge 118. In addition, a small chamfered portion means, for example, that if the chamfered portion has a curved shape, the radius of curvature of the curved surface is small, and if the chamfered portion has a flat shape, the length crossing the plane is small.

[0094] 6, preferably, a groove 11a extending from the lower surface 113 to the upper surface 114 is formed on the outer surface 112 of the first flange 11, and the outer surface side base electrode 312 is embedded in the groove 11a. This prevents the outer surface side base electrode 312 and the metal coating 313 on the outer surface side base electrode 312 from extending unnecessarily on the outer surface 112, and reduces connection between adjacent first electrode portion 31 and second electrode portion 32 via the outer surface side base electrode 312 and the metal coating 313, enabling further miniaturization.

[0095] The configuration of the first flange 11 has been described above, but in the coil device 1, the second flange 12 has the same configuration as the first flange 11. As a result, the second flange 12 has the same configuration as the first flange 11, and the above-mentioned effects are more effectively exhibited. Note that it is sufficient that at least either the first flange 11 or the second flange 12 satisfies the above-mentioned configuration.

[0096] (Detailed configuration of each part) (Plate member 15) Plate member 15 has a length of approximately 3.3 mm, a width of approximately 2.6 mm, and a thickness of approximately 0.7 mm. The thickness of plate member 15 is preferably 0.3 to 2.0 mm; a thickness of 0.3 mm or greater ensures a sufficient inductance value, and a thickness of 2.0 mm or less enables a low profile. Plate member 15 is preferably chemically cleaned, which improves the wettability of the adhesive used to bond it to core 10 and the adhesive strength between core 10 and plate member 15. The flatness of the lower surface of plate member 15 is preferably 5 μm or less, which reduces the gap between first flange 11 and second flange 12 and prevents a decrease in inductance value. It is preferable that the length and width of the plate member 15 are approximately 0.1 mm larger than the length and width of the core 10, so that a connection area overlapping with the first flange portion 11 and the second flange portion 12 is secured to prevent longitudinal and lateral misalignment that is likely to occur when the plate member 15 is attached to the core 10, and a stable closed magnetic circuit is formed, thereby suppressing a decrease in the inductance value.

[0097] (Core 10) The winding core 13 of the core 10 has a shape that extends from the first end 131 to the second end 132, and the cross section perpendicular to the direction in which the winding core 13 extends is hexagonal. However, the cross section may be another polygonal shape such as a square, a circle, an ellipse, or an appropriate combination of these.

[0098] Core 10 has a length of approximately 3.2 mm, a width of approximately 2.5 mm, and a thickness of approximately 1.7 mm. Note that the length is the distance between outer surfaces 112, 122 of first flange 11 and second flange 12, the width is the distance between first side surface 115 and second side surface 115 of first flange 11, and the thickness is the distance between bottom surface 113 and top surface 114 of first flange 11. Core 10 has a distance (standoff) from bottom surfaces 113, 123 of first and second flanges 11, 12 to the bottom end of winding core 13 of approximately 0.7 mm. The standoff is preferably 0.50 to 1.50 mm, and by setting the standoff to 0.50 mm or more, stray capacitance generated between the mounting board and wires 21, 22 is reduced. Furthermore, since a sufficient distance is maintained between the separation portion between the first wire 21 and the second wire 22 and the portions of the wires 21, 22 thermocompression-bonded to the electrode portions 31-34, stress generated at the separation portion is alleviated, reducing the risk of wire breakage in the wires 21, 22 or short circuits between the wires due to coating breakdown. Furthermore, since the standoff is 1.50 mm or less, a low profile is achieved and the thickness of the plate member 15 is ensured. The length direction and width direction are both parallel to the mounting board on which the coil device 1 is mounted, with the direction in which the winding core portion 13 extends being defined as the length direction and the direction perpendicular to the length direction being defined as the width direction. Furthermore, the height direction is a direction perpendicular to the mounting board, and the length direction, width direction, and height direction are perpendicular to one another.

[0099] The core 10 is preferably chemically cleaned, which improves the wettability of the adhesive used to bond the core 10 to the plate member 15 and the adhesive strength between the core 10 and the plate member 15. The surfaces of the first flange 11 and the second flange 12 facing the plate member 15 preferably have a flatness of 5 μm or less, which reduces gaps between the first flange 11 and the second flange 12 and prevents a decrease in inductance. The ridges between the outer surfaces 112, 122, the side surfaces 115, 125, and the top surfaces 114, 124 of the first flange 11 and the second flange 12 are preferably chamfered. This creates a reservoir for the adhesive used to bond the core 10 to the plate member 15 at the outer and upper edge portions of the side surfaces of the first flange 11 and the second flange 12, making it less likely for the adhesive to leak onto the outer and side surfaces of the first flange 11 and the second flange 12. On the other hand, it is preferable that the ridges between the inner surfaces 111, 121 and the side surfaces 115, 125 and the ridges between the inner surfaces 111, 121 and the top surfaces 114, 124 are not chamfered. This increases the connection area with the plate member 15 at the top surface ends on the inner side of the first flange 11 and the second flange 12, where magnetic flux is likely to concentrate, and shortens the magnetic path length, thereby suppressing a decrease in inductance value. The thickness of the winding core 13 is approximately 0.6 mm. The thickness of the winding core 13 is preferably 1 mm or less, which ensures both standoff and the thickness of the plate member 15.

[0100] (First and second wires 21, 22) The first wire 21 and the second wire 22 are composed of a conductor wire made of a good conductor such as Cu, Ag, or Au, and a resin coating such as imide-modified polyurethane, polyimide amide, or fluororesin that covers the conductor wire. For example, the conductor wire has a wire diameter of 30 μm, and the coating has a thickness of 10 μm. The conductor diameter is preferably 15 to 100 μm, and the coating has a thickness of approximately 8 to 20 μm. The surface of the coating may be coated with an active agent or the like.

[0101] (Method of manufacturing coil component 1) The following describes a method for manufacturing coil component 1. The method for manufacturing coil component 1 includes the steps of twisting first wire 21 and second wire 22 together in a first twist direction, for example, the Z twist direction, to form first stranded wire portion 25a (see FIG. 2A), twisting first wire 21 and second wire 22 together in a second twist direction opposite to the first twist direction, for example, the S twist direction, to form second stranded wire portion 25b (see FIG. 2B), winding first stranded wire portion 25a around winding core portion 13 of core 10 to manufacture first coil component 1a (see FIG. 8), and winding second stranded wire portion 25b around winding core portion 13 of core 10 to manufacture second coil component 1b (see FIG. 8). This allows for the mixing of the second coil component 1b and the first coil component 1a in which the twisting direction of the twisted wire portion 25 is opposite to that of the second coil component 1b, thereby eliminating the need to constantly rotate the winding nozzle in a fixed direction during the manufacture of the coil component 1, thereby reducing the occurrence of kinks in the first wire 21 and the second wire 22.

[0102] 7, in the step of forming first stranded wire portion 25a, winding nozzle 60 holding first wire 21 and second wire 22 is revolved around winding core 13 of core 10 (that is, around axis L of winding core 13) in a first direction, for example, clockwise, without being rotated. On the other hand, in the step of forming second stranded wire portion 25b, winding nozzle 60 is revolved around winding core 13 of core 10 in a direction opposite to the first direction, for example, counterclockwise, without being rotated. In this manner, winding nozzle 60 revolves in opposite directions in the step of forming first stranded wire portion 25a and the step of forming second stranded wire portion 25b, and therefore twists are less likely to remain in first wire 21 and second wire 22.

[0103] Furthermore, in the above manufacturing method, it is preferable that the number of inversion portions in the stranded wire portion 25 is an even number. According to this, when manufacturing the coil device 1, the stranding directions of the stranded wire portions 25 wound around the winding core portion 13 at the beginning and the end are the same, and therefore twists in the first wire 21 and the second wire 22 tend to remain for each manufacturing unit. Therefore, the above manufacturing method allows for the mixing of coil devices 1 in which the stranded wire portions 25 are twisted in opposite directions, which further effectively reduces the occurrence of kinks in the first wire 21 and the second wire 22.

[0104] (Coil parts packaging) Fig. 8 is a simplified diagram showing a packaging form of coil components 1. As shown in Fig. 8, a plurality of coil components 1 are packaged in a taping reel 40. The taping reel 40 has a tape 41 and a reel 42 around which the tape 41 is wound. The tape 41 has a plurality of pockets 411 arranged along the longitudinal direction, each of which stores one of the plurality of coil components 1. The number of coil components 1 contained in the taping reel 40 is, for example, 8,000.

[0105] Here, pocket 411 contains a mixture of first coil components 1a and second coil components 1b manufactured by the above-described manufacturing method for coil component 1. That is, in taping reel 40, the plurality of coil components 1 include first coil components 1a in which the twist direction of twisted wire portions 25a is opposite to the twist direction of twisted wire portions 25b of second coil components 1b. This allows for a mixture of second coil components 1b and first coil components 1a in which the twist direction of twisted wire portions 25a is opposite to that of second coil components 1b, thereby eliminating the need to constantly revolve the winding nozzle in a fixed direction during manufacturing of coil component 1 and reducing the occurrence of kinks in first wire 21 and second wire 22.

[0106] As in the above-described method for manufacturing the coil component 1, the first coil component 1a and the second coil component 1b have opposite winding directions for the coil 20 around the winding core 13. That is, the winding direction of the coil 20 of the first coil component 1a around the winding core 13 is, for example, clockwise, which is opposite to the winding direction of the coil 20 of the second coil component 1b around the winding core 13, for example, counterclockwise. This makes it easy to reverse the directions of revolution of the winding nozzle when manufacturing the first coil component 1a and the second coil component 1b, thereby easily reducing the occurrence of kinks in the first wire 21 and the second wire 22. When the twisted wire portions of the first and second coil components 1a and 1b have a reversal portion where the twist direction is reversed, the twist direction of the twisted wire portion of the first coil component 1a being opposite to the twist direction of the twisted wire portion of the second coil component 1b means, for example, that when the twist direction of the twisted wire portion of the first coil component 1a changes in the order of S twist, Z twist, and S twist, the twist direction of the twisted wire portion of the second coil component 1b changes in the order of Z twist, S twist, and Z twist.

[0107] Preferably, the taping reel 40 has two or more pockets 411, each containing a first coil component 1a, arranged in succession, as shown in Fig. 8. For example, in the manufacturing process of the coil component 1, even if coil components 1 having twisted wire portions 25 in opposite twist directions are manufactured alternately, in the process of storing the coil components 1 in the pockets 411 of the tape 41, coil components 1 that have been determined to be unacceptable in visual inspection or characteristic inspection are rejected and the coil components 1 are transferred. Therefore, if coil components 1 having twisted wire portions 25 in opposite twist directions are to be arranged alternately in the taping reel 40, a process of rearranging the order of the coil components 1 by twist direction, for example, a process of sorting and arranging the first coil component 1a and the second coil component 1b, is required after the visual inspection or characteristic inspection and before the process of storing the coil components 1 in the pockets 411 of the tape 41. On the other hand, when two or more pockets 411 storing the first coil components 1a are arranged in succession as described above, it is permissible to store the first coil components 1a in succession in the tape 41, so that after the appearance inspection and characteristic inspection, there is no need to perform a process of rearranging the order of the coil components 1 before the process of storing the coil components 1 in the tape 41, thereby shortening the manufacturing time per taping reel 40.

[0108] In particular, it is preferable that the taping reel 40 has portions where the number of consecutively arranged pockets 411 storing first coil components 1a differs from the number of consecutively arranged pockets 411 storing second coil components 1b. That is, the method for manufacturing the taping reel 40 includes the steps of manufacturing the first coil components 1a and the second coil components 1b, preparing a tape 41 having a plurality of pockets 411 arranged along the longitudinal direction, storing the first coil components 1a in one of the plurality of pockets 411, and storing the second coil components 1b in one of the plurality of pockets 411, and it is preferable that the steps of storing the first coil components 1a and storing the second coil components 1b are performed irregularly. This allows the first coil components 1a and the second coil components 1b to be stored irregularly in the multiple pockets 411, eliminating the need for a process of rearranging the order of the coil components 1 before storing the coil components 1 in the tape 41, thereby shortening the manufacturing time per taping reel 40.

[0109] Furthermore, an electronic component may be manufactured by mounting the coil component 1 removed from such a taping reel 40 on a mounting board. That is, the electronic component includes a mounting board and a plurality of coil components 1 mounted on the mounting board. The plurality of coil components 1 include a first coil component 1a in which the twist direction of the twisted wire portions 25 is opposite to the twist direction of the twisted wire portions 25 of other second coil components 1b. This allows for a mixture of first coil components 1a in which the twist direction of the twisted wire portions 25 is opposite to that of other second coil components 1b, thereby eliminating the need to constantly revolve the winding nozzle in a fixed direction during the manufacture of the coil component 1 and reducing the occurrence of kinks in the first wire 21 and the second wire 22.

[0110] (Second embodiment) 9 is a simplified cross-sectional view showing a second embodiment of a coil device. The second embodiment differs from the first embodiment in the position at which the wires are twisted. This difference in configuration will be described below. The other configurations are the same as those of the first embodiment, and the same reference numerals as those of the first embodiment are used, and their description will be omitted.

[0111] 9, in the coil device 1A of the second embodiment, the first wire 21 (shown by the solid line) and the second wire 22 (shown by the dashed-dotted line) are twisted together from a part of the non-winding region Z2A to the entire winding region Z1A of the coil 20A. That is, in the coil device 1A, not only the winding region Z1A of the coil 20A but also the non-winding region Z2A of the coil 20A has a twisted wire portion 25, and the portion of the non-winding region Z2A adjacent to the winding region Z1A is the twisted wire portion 25. Therefore, it is possible to further reduce the difference in line length between the first wire 21 and the second wire 22 and the imbalance in the inter-wire capacitance between the first wire 21 and the second wire 22, thereby reducing deterioration of the mode conversion characteristics.

[0112] In order to ensure that the non-winding region Z2A of the coil 20A also has the twisted wire portion 25 as described above, for example, the twisted wire portion 25 may be formed in advance before winding the coil 20A around the winding core portion 13, and some of the twisted wire portion 25 may be left in the non-winding region Z2A rather than all of the twisted wire portion 25 being in the winding region Z1A.

[0113] Furthermore, the non-winding region Z2A continues from the twisted wire portion 25 and has a non-twisted wire portion 26 where the first wire 21 and the second wire 22 are untwisted from each other, and in the non-twisted wire portion 26, the lengths of the first wire 21 and the second wire 22 are the same. Therefore, it is possible to further reduce the difference in line length between the first wire 21 and the second wire 22 and the imbalance in the inter-wire capacitance between the first wire 21 and the second wire 22, including the non-winding region Z2A, and to further reduce deterioration of the mode conversion characteristics.

[0114] As described above, in order to make the lengths of the first wire 21 and the second wire 22 the same in the untwisted wire portion 26, for example, the pre-formed twisted wire portion 25 may be partially untwisted in the non-winding region Z2A. In this case, the untwisted first wire 21 and the second wire 22 may have a bent shape as a trace of the twist. In this case, the bent shapes of the first wire 21 and the second wire 22 may be the same or different in the region from the final end of the twisted wire portion 25 to the electrode portions 31 to 34. In particular, it is preferable that the bent shapes are shaped toward the electrode portions 31 to 34 to be connected to each other, which prevents stress from being generated in the first wire 21 and the second wire 22 when they are connected, thereby reducing the occurrence of wire breakage.

[0115] (Third embodiment) 10 is a simplified bottom view showing a coil device according to a third embodiment. The third embodiment differs from the first embodiment in the number of twists in the twisted wire portion. This difference in configuration will be described below. The other components are the same as those in the first embodiment, and the same reference numerals as those in the first embodiment are used, and their description will be omitted.

[0116] As shown in Fig. 10, in the coil device 1B of the third embodiment, the number of twists per turn of the stranded wire portion 25B is not an integer. This means that the positional relationship between the first wire 21 and the second wire 22 in each turn of the stranded wire portion 25B is not fixed, which further reduces the inter-wire capacitance of the stranded wire portion 25B and the imbalance in the capacitance between the mounting board and the wires. Note that, for simplicity, in Fig. 10, the portion of the stranded wire portion 25B where the first wire 21 is positioned outside the second wire 22 is shown as white, and the portion where the second wire 22 is positioned outside the first wire 21 is shown as hatched.

[0117] It is more preferable that the number of twists per turn of stranded wire portion 25B is n1 / n2 (n2 is a prime number). This increases the number of turns required to restore the same positional relationship between first wire 21 and second wire 23 in each turn of stranded wire portion 25B, thereby further reducing the inter-wire capacitance of stranded wire portion 25B and the imbalance in capacitance between the mounting board and the wire.

[0118] (Example) As examples and comparative examples of coil components according to the present disclosure, the results of a simulation of the line-to-line capacitance occurring in the bank region are described below. Figures 11A, 11B, 11C, 12A, and 12B are diagrams showing the configuration of the bank region in which the line-to-line capacitance simulation was performed.

[0119] Specifically, as shown in Fig. 11A, the bank region of Example 1 is composed of three turns (the first turn through the third turn) of the first layer wound continuously around the winding core, and one turn (the fourth turn) of the second layer wound over the second and third turns. As shown in Fig. 11B, the bank region of Example 2 is composed of four turns (the first turn through the fourth turn) of the first layer wound continuously around the winding core, and two turns (the fifth turn) of the second layer wound over the second and third turns, and a sixth turn wound over the third and fourth turns. As shown in Fig. 11C, the bank region of Example 3 is composed of four turns (the first turn through the fourth turn) of the first layer wound continuously around the winding core, and one turn (the fifth turn) of the second layer wound over the third and fourth turns.

[0120] As shown in Fig. 12A, the bank region of Comparative Example 1 is composed of three turns, the first turn through the third turn, in which the first layer is wound continuously around the winding core, two turns, the fourth turn of the second layer being wound over the first and second turns, and two turns, the fifth turn being wound over the second and third turns. As shown in Fig. 12B, the bank region of Comparative Example 2 is composed of four turns, the first turn through the fourth turn, in which the first layer is wound continuously around the winding core, and three turns, the fifth turn of the second layer being wound over the first and second turns, the sixth turn being wound over the second and third turns, and the seventh turn being wound over the third and fourth turns.

[0121] As described above, in the bank regions of Examples 1 to 3, the number of turns in the second layer is two or more turns less than the number of turns in the first layer, and in the bank regions of Comparative Examples 1 and 2, the number of turns in the second layer is only one turn less than the number of turns in the first layer. The inter-line capacitance generated between the first and second layers was determined by simulation for each of Examples 1 to 3 and Comparative Examples 1 and 2. Table 1 shows the results of the simulation.

[0122] [Table 1]

[0123] As can be seen from Table 1, when the first layer had 3 turns, Example 1 was able to reduce the line capacitance by 0.08 pF (approximately 12%) compared to Comparative Example 1, and when the first layer had 4 turns, Examples 2 and 3 were able to reduce the line capacitance by 0.34 (approximately 33%) and 0.42 (approximately 41%), respectively, compared to Comparative Example 2.

[0124] (Variation) The present disclosure is not limited to the above-described embodiments, and design modifications are possible without departing from the spirit of the present disclosure. For example, the features of the first to third embodiments may be combined in various ways.

[0125] In the above embodiment, the coil component is used as a common mode choke coil, but it may also be used as a wire-wound coil in which multiple wires are wound around a winding core, such as a transformer or a coupled inductor array. In these wire-wound coils as well, reducing the inter-wire capacitance is useful.

[0126] In the above embodiment, a plate member is provided, but the plate member may be omitted. In the above embodiment, the coil includes two wires, but the coil may include multiple wires, and may include three or more wires. In this case, the twisted wire portion is not limited to a configuration in which two wires are twisted together, but may be a configuration in which three or more wires are twisted together.

[0127] In the above embodiment, the bank region is formed by winding the stranded wire portion in two layers, but the bank region may also be formed by winding the stranded wire portion in three or more layers. In this case, at least in relation to the first layer wound directly around the winding core and the second layer wound on top of the first layer, the number of turns in the second layer is sufficient to be loosely wound by at least two turns less than the number of turns in the first layer, and there are no limitations on the configuration of the third layer and subsequent layers. However, even for the third layer and subsequent layers, it is more preferable that the number of turns in the upper layer is at least two turns less than the number of turns in the layer immediately below, and it is preferable that the number of turns in the uppermost layer is one turn.

[0128] In the above embodiment, first to fifth bank regions B1 to B5 are provided, and in four of the first to fourth bank regions B1 to B4, the number of turns in the second layer is loosely wound, i.e., two or more turns less than the number of turns in the first layer. However, this configuration is not limited. The stranded wire portion only needs to have at least one loosely wound bank region. For example, the number of loosely wound bank regions may be one to three, or five or more. There is also no limit to the number of tightly wound bank regions. All bank regions may be loosely wound, or there may be two or more tightly wound bank regions. There is also no particular limitation on the positional relationship between the loosely wound bank region and the tightly wound bank region. The tightly wound bank region may be located between or between the loosely wound bank regions. Furthermore, a configuration other than a bank region may be included. For example, there may be a single-layer winding region where no stranded wire portion is wound on the first layer, or a region where the stranded wire portion is alternately wound between the first and second layers. Furthermore, there may or may not be a gap between these regions; for example, there may be a bank region adjacent to the first or last turn of the first layer of the bank region, a single-layer winding region, or a region where the twisted wire portion is wound alternately in the first and second layers.

[0129] In the above embodiment, the first bank region B1 has four turns in the first layer and one turn in the second layer, and the second to fourth bank regions B2 to B4 have four turns in the first layer and two turns in the second layer. However, the loosely wound bank region is not limited to this. Specifically, for example, the loosely wound bank region may have three turns in the first layer and one turn in the second layer, or the loosely wound bank region may have five or more turns in the first layer. Furthermore, the shape of the loosely wound bank region is not limited to a shape in which the second layer is offset toward the final turn of the first layer, but may also be offset to the opposite side or centered. Note that when the stranded wire portion has a tightly wound bank region, the tightly wound bank region is not particularly limited as described above, and the first layer may have two turns or four or more turns.

[0130] In the above embodiment, the inner surfaces of the first flange and the second flange are perpendicular to the extension direction of the winding core, but the inner surfaces of the first flange and the second flange may be parallel to each other and have inclined portions that intersect obliquely with the extension direction of the winding core. This allows the wire to be drawn out along the inclined portions to the first to fourth electrode portions when the wire is wound around the winding core, reducing portions of the winding core that do not contribute to the winding and increasing the connection areas of the first and second flanges with the plate members.

[0131] In the above embodiment, the electrode portion includes a lower-surface-side base electrode provided on the lower surface and an outer-surface-side base electrode provided on the outer surface, and the outer-surface-side base electrode has a shape extending from an outer-surface end of the lower-surface-side base electrode onto the outer surface. However, this is not limited to this. For example, the electrode portion may have only a lower-surface-side base electrode and no outer-surface-side base electrode.

[0132] In the above embodiment, the coil component manufacturing method includes a step of twisting multiple wires together in a first twist direction to form a first stranded wire portion, a step of twisting multiple wires together in a second twist direction opposite to the first twist direction to form a second stranded wire portion, a first coil manufacturing step of winding at least the first stranded wire portion around a core winding core, and another coil manufacturing step of winding at least the second stranded wire portion around a core winding core. However, this is not limited to this. For example, only stranded wire portions with the same twist direction may always be wound around a winding core. Therefore, similarly, for multiple coil components stored in a taping reel or multiple coil components mounted on a mounting board, all coils may be wound around the winding core in the same direction. Furthermore, the step of forming the stranded wire portion is not limited to a method of revolving a winding nozzle around a winding core without rotating it, and may involve a method of winding a pre-twisted stranded wire portion around a winding core. [Explanation of symbols]

[0133] 1, 1A, 1B Coil parts 1a First coil component 1b Second coil part 10 cores 11 First flange 12 Second flange 13 Winding core 15 Plate members 20,20A coil 21 First Wire 22 Second Wire 25,25B twisted wire section 25a First twisted wire section 25b Second twisted wire section 26 Non-twisted wire section 31~34 1st~4th electrode part 40 Taping Reel 41 Tape 411 Pocket 42 reels B1~B4 1st to 4th bank areas Z1, Z1A Winding area Z2, Z2A Non-winding area

Claims

1. a core having a winding core portion; a coil including a plurality of wires wound around the winding core; Equipped with the coil has a twisted wire portion in which the plurality of wires are twisted together, the plurality of wires include at least a first wire and a second wire, and ends of the first wire and the second wire are electrically connected to different electrodes, respectively; the stranded wire portion has a bank region including a first layer wound continuously around the winding core portion by a plurality of turns, and a second layer wound continuously from the first layer onto the first layer, the stranded wire portion has a plurality of bank regions along the winding core portion, a bank region closest to one end in a direction along the winding core portion is densely wound in which the number of turns of the second layer is one turn less than the number of turns of the first layer, and all bank regions other than the densely wound bank region are loosely wound in which the number of turns of the second layer is two or more turns less than the number of turns of the first layer.

2. 2. The coil component according to claim 1, wherein there are a plurality of the loosely wound bank regions, and the bank region closest to the other end in the direction along the winding core portion among the plurality of loosely wound bank regions has a larger difference between the number of turns of the first layer and the number of turns of the second layer than all of the loosely wound bank regions other than the bank region closest to the other end.

3. The coil component according to claim 1 , wherein the number of twists per turn of the twisted wire portion is not an integer.

4. The number of twists per turn of the twisted wire portion is not an integer, 2. The coil component according to claim 1, wherein the number of twists per turn of the twisted wire portion is n1 / n2 (n2 is a prime number).

5. The coil component according to claim 1 , wherein the twisted wire portion has a reversed portion where the twisting direction is reversed.

6. the core includes a first flange portion provided at a first end of the winding core portion and a second flange portion provided at a second end of the winding core portion, The electrode assembly further includes a first electrode portion and a second electrode portion provided on the first flange portion, and a third electrode portion and a fourth electrode portion provided on the second flange portion, 5. The coil component according to claim 1, wherein the first wire is electrically connected to the first electrode portion and the third electrode portion, the second wire is electrically connected to the second electrode portion and the fourth electrode portion, and the first wire and the second wire are wound around the winding core portion in the same direction.

7. 7. The coil component according to claim 6, wherein the coil has a winding region wound around the winding core portion and a non-winding region separated from the winding core portion and connected to the first electrode portion, the second electrode portion, the third electrode portion, or the fourth electrode portion, and the first wire and the second wire are untwisted from each other in a portion of the winding region adjacent to the non-winding region.

8. 7. The coil component according to claim 6, wherein the coil has a winding region wound around the winding core portion and a non-winding region separated from the winding core portion and connected to the first electrode portion, the second electrode portion, the third electrode portion, or the fourth electrode portion, and a portion of the non-winding region adjacent to the winding region is a twisted wire portion.

9. 9. The coil component of claim 8, wherein the non-winding region continues from the twisted wire portion and has a non-twisted wire portion in which the first wire and the second wire are untwisted, and in the non-twisted wire portion, the length of the first wire and the length of the second wire are the same.

10. 10. The coil component according to claim 1, wherein in the bank region of the loosely wound coil, the second layer is shifted toward the final turn of the first layer.

11. The coil component according to claim 10 , wherein the second layer includes a portion wound onto a final turn of the first layer.

12. The coil component according to claim 1 , wherein the number of turns in the top layer in the loosely wound bank region is one.

13. The coil component according to claim 1 , wherein the number of turns of the first layer in the loosely wound bank region is 5 turns or less.

14. the number of layers of each of the plurality of bank regions is two; the plurality of bank regions are three or more bank regions, 14. The coil component according to claim 1, wherein in all of the plurality of bank regions except for two bank regions located at both ends in a direction along the winding core portion, the number of turns in the first layer is four, and the number of turns in the second layer is two.

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