Common mode choke coil

Abstract

To provide a winding type common-mode choke coil capable of reducing local deviation in floating capacitance between different turns and reducing a mode conversion characteristic.SOLUTION: First and second wires 11, 12 are connected to first and second terminal electrodes 21, 22 and third and fourth wires 13, 14 are connected to third and fourth terminal electrodes 23, 24. Around a winding core part 3, the first wire 11, the third wire 13, the fourth wire 14, and the second wire 12 are wound so as to form a first layer, a second layer, a third layer, and a fourth layer, respectively. A predetermined turn of the first wire 11 is displaced by two or more turns toward a second end 5 relative to the same turn of the third wire 13 as the corresponding turn of the first wire 11 counting from a first end 4 side. A predetermined turn of the second wire 12 is displaced by two or more turns toward the first end 4 relative to the same turn of the fourth wire 14 as the corresponding turn of the second wire 12 counting from the first end 4 side.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a common mode choke coil, and more particularly to a wire-wound common mode choke coil having a structure in which a plurality of wires are wound around a winding core portion provided in a core. [Background technology]

[0002] A general configuration of a common mode choke coil 31 according to the present invention will be described with reference to FIGS.

[0003] 9, the common mode choke coil 31 includes a core 32, and a first wire 33 and a second wire 34, each of which constitutes an inductor. The common mode choke coil 31 may also include a top plate 45.

[0004] The core 32 has a winding core portion 35, a first flange portion 36 provided on a first end 38 side of the winding core portion 35 in the axial direction, and a second flange portion 37 provided on a second end 39 side opposite the first end 38 side.

[0005] A first terminal electrode 41 and a third terminal electrode 43 are provided on the first flange 36, and a second terminal electrode 42 and a fourth terminal electrode 44 are provided on the second flange 37. As can be seen from the positions of the terminal electrodes 41 to 44, Fig. 9 illustrates the common mode choke coil 31 with the mounting surface facing the mounting board facing upward.

[0006] The first wire 33 and the second wire 34 are spirally wound in parallel around the winding core 35 from the first end 38 toward the second end 39. Ends of the first wire 33 are connected to a first terminal electrode 41 and a second terminal electrode 42, respectively, and ends of the second wire 34 are connected to a third terminal electrode 43 and a fourth terminal electrode 44, respectively.

[0007] The common mode choke coil 31 having the above-described configuration provides an equivalent circuit as shown in Fig. 10. In Fig. 10, elements corresponding to those shown in Fig. 9 are given the same reference numerals.

[0008] Referring to FIG. 10, the common mode choke coil 31 includes a first inductor 46 formed by a first wire 33 connected between a first terminal electrode 41 and a second terminal electrode 42, and a second inductor 47 formed by a second wire 34 connected between a third terminal electrode 43 and a fourth terminal electrode 44.

[0009] 9, the first wire 33 is wound to form a first layer around the circumferential surface of the winding core 35, and the second wire 34 is wound to form a second layer on the outer circumferential side of the first layer, with a portion of the second wire 34 fitting into a recess formed between adjacent turns of the first wire 33. In this way, the above-described first inductor 46 and second inductor 47 are magnetically coupled to each other.

[0010] In the common mode choke coil 31 described above, when the signal frequency input thereto increases, a problem may arise in which the mode conversion characteristic, which is the proportion of the input differential signal components that are converted to common mode noise and output, becomes more pronounced. For example, Japanese Patent Application Laid-Open No. 2014-120730 (Patent Document 1) cites an imbalance in the stray capacitance (distributed capacitance) that occurs between different turns of the first wire 33 and the second wire 34, as the cause of this problem.

[0011] Therefore, as shown in FIG. 11, in the common mode choke coil 31a described in Patent Document 1, the following winding pattern of the wires 33 and 34 is adopted.

[0012] 11, the cross section showing the first wire 33 is shaded to clearly distinguish it from the second wire 34. Furthermore, within each cross section of the first wire 33 and the second wire 34 shown in FIG. 11, the numbers of turns "1" to "12" are written, counting from the first end 38 side where the first flange 36 of the winding core 35 is located.

[0013] 11, of the portions of the first wire 33 and the second wire 34 wound around the winding core 35, the portions located on the near side of the winding core 35 are shown by solid lines, and the portions hidden by the winding core 35 are shown by dashed lines. Note that Fig. 11 does not show all of the portions of the wires 33 and 34 located on the near side of the winding core 35 or the portions hidden by the winding core 35.

[0014] Referring to FIG. 11, when classified based on the winding state of the first wire 33 and the second wire 34, (1) A first winding region A in which the turns of the first wire 33 and the second wire 34 at the same number are adjacent to each other, and the turn of the first wire 33 is located closer to the first end 38 than the turn of the second wire 34 at the same number; (2) a second winding region B in which the turns of the first wire 33 and the second wire 34 at the same number are adjacent to each other, and the turn of the first wire 33 is located closer to the second end 39 than the turn of the second wire 34 at the same number; (3) a switching region C located between the first winding region A and the second winding region B, where the first wire 33 and the second wire 34 cross each other, thereby switching the positional relationship between the turns of the first wire 33 and the turns of the second wire 34; The first winding region A, the switching region C, and the second winding region B are arranged in this order along the axial direction of the winding core 35.

[0015] In the technology described in Patent Document 1, in order to solve the problem of significant mode conversion characteristics, the winding structure of the first wire 33 and the second wire 34 in the first winding region A and the winding structure of the first wire 33 and the second wire 34 in the second winding region B are made symmetrical with respect to the center line CL of the switching region C in order to balance the stray capacitance (distributed capacitance) generated between different turns of the first wire 33 and the second wire 34. In other words, the number of turns of each of the first wire 33 and the second wire 34 in the first winding region A and the number of turns of each of the first wire 33 and the second wire 34 in the second winding region B are made equal to each other.

[0016] In the technology described in Patent Document 1, as described above, the first winding region A, the switching region C, and the second winding region B are arranged in this order along the axial direction of the winding core 35, thereby making the winding structure of the wires 33 and 34 symmetrical with respect to the center line CL of the switching region C. As a result, inter-turn capacitance is generated uniformly in both the first wire 33 and the second wire 34, thereby suppressing imbalance in impedance between the first wire 33 and the second wire 34. This is said to reduce the mode conversion characteristics and realize a high-quality common mode choke coil. [Prior art documents] [Patent documents]

[0017] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-120730 Summary of the Invention [Problem to be solved by the invention]

[0018] In the technology described in Patent Document 1, in order to reduce the mode conversion characteristics, as described above, the winding structure of wires 33 and 34 is made symmetrical. Therefore, compared to the general common mode choke coil 31 described with reference to Figures 9 and 10, the mode conversion characteristics can be reduced to some extent.

[0019] However, even with the technology described in Patent Document 1, the mode conversion characteristic does not become completely zero. The reason for this is that the circuit formed in association with the common mode choke coil 31a is divided into two parts, the first half and the second half, in the signal propagation direction. Therefore, although the imbalance in stray capacitance between different turns is eliminated macroscopically, that is, when looking at the entire turn, stray capacitance between different turns occurs locally, for example, when looking at only the first half or only the second half. The present inventors discovered that for this reason, the mode conversion characteristic gradually deteriorates in the high frequency range, as shown in Figure 4, which will be described later.

[0020] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a common mode choke coil that can reduce local deviations in stray capacitance between different turns. [Means for solving the problem]

[0021] In order to solve the above-mentioned technical problems, the common mode choke coil according to the present invention comprises: In the first phase, The core includes a winding core portion, a first flange portion provided at a first end side in the axial direction of the winding core portion, and a second flange portion provided at a second end side opposite the first end side in the axial direction of the winding core portion, a first wire, a second wire, a third wire, and a fourth wire each spirally wound in parallel around the winding core portion, a first terminal electrode and a third terminal electrode provided at the first flange portion, and a second terminal electrode and a fourth terminal electrode provided at the second flange portion.

[0022] One end of each of the first wire and the second wire is connected to a first terminal electrode, the other end of each of the first wire and the second wire is connected to a second terminal electrode, one end of each of the third wire and the fourth wire is connected to a third terminal electrode, and the other end of each of the third wire and the fourth wire is connected to a fourth terminal electrode.

[0023] The first wire is wound around the core to form a first layer, and the third wire is , th The fourth wire is wound around the outer periphery of the first layer to form the second layer. , th The second wire is wound around the outer periphery of the second layer to form a third layer. , th The fourth layer is wound around the outer periphery of the third layer.

[0024] A predetermined turn of the first wire is located closer to the second end than the turn of the third wire that is the same as the turn of the first wire when counted from the first end. s The predetermined turn of the second wire is shifted by more than one turn toward the first end side from the turn of the fourth wire that is the same as the turn of the second wire when counted from the first end side. t More than a turn off (where s and t are natural numbers, and one of s and t is 2 and the other is 1.) It is characterized by the following.

[0025] This invention In the above, in addition to the first aspect in which a configuration including four wires is adopted, there is also a second aspect in which a configuration including three wires is adopted. In a second aspect, the common mode choke coil of the present invention comprises a core having a winding core portion, a first flange portion provided at a first end side in the axial direction of the winding core portion, and a second flange portion provided at a second end side opposite the first end side in the axial direction of the winding core portion, a first wire, a second wire, and a third wire wound spirally in parallel around the winding core portion, first and third terminal electrodes provided at the first flange portion, and second and fourth terminal electrodes provided at the second flange portion. One end of each of the first wire and the second wire is connected to a first terminal electrode, the other end of each of the first wire and the second wire is connected to a second terminal electrode, one end of the third wire is connected to a third terminal electrode, and the other end of the third wire is connected to a fourth terminal electrode. The first wire is wound around the winding core to form a first layer, the third wire is wound around the outer periphery of the first layer to form a second layer, and the second wire is wound around the outer periphery of the second layer to form a third layer. The first wire and the third wire are characterized in that a certain turn of the first wire, counted from the first end, is shifted toward the second end from the turn of the third wire that is in the same position as the turn, and the second wire and the third wire are characterized in that a certain turn of the second wire, counted from the first end, is shifted toward the first end from the turn of the third wire that is in the same position as the turn.

[0026] In the technology described in Patent Document 1, a first winding region and a second winding region, which have mutually opposite positional relationships for two paired wires, are arranged in the axial direction of the winding core portion. In contrast, in this invention, simply put, a configuration is adopted in which a region corresponding to the first winding region and a region corresponding to the second winding region are stacked in a direction perpendicular to the axial direction of the winding core portion. [Effects of the Invention]

[0027] According to this invention, four wires or three wires This can reduce local deviations in stray capacitance between different turns in the first inductor or the second inductor configured by the above. [Brief explanation of the drawings]

[0028] [Figure 1] 1 is a plan view showing the appearance of a common mode choke coil 1 according to a first embodiment disclosed in this specification, viewed from the mounting surface side. [Figure 2] 2 is a cross-sectional view schematically showing the winding state of first to fourth wires 11 to 14 in the common mode choke coil 1 shown in FIG. [Figure 3] 3 is an enlarged cross-sectional view showing a part of the first to fourth wires 11 to 14 for explaining stray capacitances C1 and C2 generated between the first to fourth wires 11 to 14 shown in FIG. 2. FIG. [Figure 4] 1A and 1B are diagrams showing the frequency characteristics of the mode conversion characteristics of a common mode choke coil, in which (A) shows the characteristics of a common mode choke coil employing a two-layer winding called layer winding, as described in Patent Document 1 as a comparative example, (B) shows the characteristics of a common mode choke coil according to the first embodiment described in Patent Document 1 as a comparative example, and (C) shows the characteristics of a common mode choke coil having the configuration described with reference to FIGS. 1 to 3. [Figure 5] 3 is a cross-sectional view schematically showing the winding state of first to fourth wires 11 to 14 in a common mode choke coil 1a which is a modified example of the common mode choke coil 1 shown in FIG. [Figure 6] 10 is a plan view showing the appearance of a common mode choke coil 1b according to a second embodiment disclosed in this specification, viewed from the mounting surface side. FIG. [Figure 7] 7 is a cross-sectional view schematically showing the winding state of first to third wires 11 to 13 in common mode choke coil 1b shown in FIG. [Figure 8]8 is an enlarged cross-sectional view of a portion of the first to third wires 11 to 13 for explaining the dimensional relationship between the central conductor 17 and the insulating coating layer 18 of the first to third wires 11 to 13 shown in FIG. [Figure 9] 1 is a perspective view showing the appearance of a conventional common mode choke coil 31 with its mounting surface facing upward. [Figure 10] FIG. 10 is an equivalent circuit diagram of the common mode choke coil 31 shown in FIG. [Figure 11] 1 is a cross-sectional view schematically showing the winding state of first and second wires 33 and 34 in a common mode choke coil 31a described in Patent Document 1. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0029] Fig. 1 shows a common mode choke coil 1 according to a first embodiment disclosed in this specification. The common mode choke coil 1 shown in Fig. 1 includes a core 2 and four wires that each constitute an inductor: a first wire 11, a second wire 12, a third wire 13, and a fourth wire 14. Fig. 2 shows a schematic cross-sectional view of the winding state of the first wire 11, the second wire 12, the third wire 13, and the fourth wire 14 in the common mode choke coil 1 shown in Fig. 1. In Fig. 2, to clearly distinguish the first wire 11 and the second wire 12 from the third wire 13 and the fourth wire 14, the cross sections of the first wire 11 and the second wire 12 are shown in white, and the cross sections of the third wire 13 and the fourth wire 14 are shaded.

[0030] The core 2 is made of a non-conductive material, more specifically, alumina as a dielectric, Ni-Zn ferrite as a magnetic material, or resin. The core 2 has an overall rectangular cross section. The wires 11 to 14 are made of, for example, insulating-coated copper wire, all of which are circular in cross section and have the same outer diameter. Note that the material and shape of the core 2 and the material, shape, and outer diameter of the wires 11 to 14 are not limited to those exemplified here.

[0031] The core 2 has a winding core 3, a first flange 6 provided on a first end 4 side of the winding core 3 in the axial direction, and a second flange 7 provided on a second end 5 side opposite the first end 4 side. The first wire 11, the second wire 12, the third wire 13, and the fourth wire 14 are spirally wound around the winding core 3 from the first end 4 side toward the second end 5 side, with substantially the same number of turns in parallel. The reason for the phrase "substantially the same number of turns" is that the positions of the start and end ends of the windings of the wires 11 to 14 on the winding core 3 may be slightly different from each other.

[0032] The first flange 6 is provided with a first terminal electrode 21 and a third terminal electrode 23, and the second flange 7 is provided with a second terminal electrode 22 and a fourth terminal electrode 24. The terminal electrodes 21 to 24 are provided, for example, by baking a conductive paste, plating a conductive metal, or attaching a metal plate with an adhesive. Note that FIG. 1 shows the common mode choke coil 1 from the mounting surface side. Also, the terminal electrodes 21 to 24 are not shown in FIG. 2.

[0033] One end of each of the first wire 11 and the second wire 12 is connected to a first terminal electrode 21, and the other end of each of the first wire 11 and the second wire 12 is connected to a second terminal electrode 22. One end of each of the third wire 13 and the fourth wire 14 is connected to a third terminal electrode 23, and the other end of each of the third wire 13 and the fourth wire 14 is connected to a fourth terminal electrode 24. These connections are made by, for example, thermocompression bonding or laser welding.

[0034] Common mode choke coil 1 may include a top plate equivalent to top plate 45 included in common mode choke coil 31 shown in Fig. 9. Like core 2, the top plate is made of, for example, alumina as a non-magnetic material, Ni-Zn ferrite as a magnetic material, or resin. When core 2 and the top plate are made of a magnetic material, the top plate is provided to connect first flange portion 6 and second flange portion 7, and thereby core 2 cooperates with the top plate to form a closed magnetic circuit.

[0035] Referring primarily to FIG. 2 , first, the first wire 11 is wound around the winding core 3 to form a first layer. Next, the third wire 13 is wound around the winding core 3 to form a second layer on the outer periphery of the first layer, with a portion of the third wire 13, more precisely, a portion of its cross section, fitting into a recess formed between adjacent turns of the first wire 11. Next, the fourth wire 14 is wound around the outer periphery of the second layer to form a third layer, with a portion of the fourth wire 14, more precisely, a portion of its cross section, fitting into a recess formed between adjacent turns of the third wire 13. Finally, the second wire 12 is wound around the outer periphery of the third layer to form a fourth layer, with a portion of the second wire 12, more precisely, a portion of its cross section, fitting into a recess formed between adjacent turns of the fourth wire 14.

[0036] In Fig. 2, the numbers of turns "1" to "20" counted from the first end 4 of the winding core 3 are written in the cross section of each of the first wire 11, second wire 12, third wire 13, and fourth wire 14. The writing of the number of turns in the cross section of the wire is also adopted in Figs. 5 and 7 described later.

[0037] Focusing on the number of turns described above, the first wire 11 constituting the first layer and the third wire 13 constituting the second layer are adjacent to each other at the same number when counted from the first end 4 of the winding core 3, but the turn of the first wire 11 is located closer to the second end 5 of the winding core 3 than the same number turn of the third wire 13. In other words, when n is a natural number from 2 to 20, the n-th turn of the third wire 13 (n: natural number) is adjacent to the (n-1)th turn of the first wire 11.

[0038] Furthermore, the second wire 12 constituting the fourth layer and the fourth wire 14 constituting the third layer are adjacent to each other at the same numbered turns when counted from the first end 4 of the winding core 3, but the turn of the second wire 12 is located closer to the first end 4 of the winding core 3 than the identical turn of the fourth wire 14. In other words, when n is a natural number from 1 to 19, the nth (n: natural number) turn of the fourth wire 14 is adjacent to the (n+1)th turn of the second wire 12.

[0039] 3, stray capacitance C1 occurs between different turns between the first wire 11 connected to the first terminal electrode 21 and the second terminal electrode 22 and the third wire 13 connected to the third terminal electrode 23 and the fourth terminal electrode 24, and stray capacitance C2 occurs between different turns between the second wire 12 connected to the first terminal electrode 21 and the second terminal electrode 22 and the fourth wire 14 connected to the third terminal electrode 23 and the fourth terminal electrode 24. Note that the first wire 11 and the second wire 12, and the third wire 13 and the fourth wire 14 are connected between the same terminal electrodes, and therefore are electrically connected in parallel and form the same signal line in the differential signal line.

[0040] Considering the misalignment of turns between the first wire 11 and the third wire 13 and the misalignment of turns between the second wire 12 and the fourth wire 14, which cause the above-described stray capacitances C1 and C2, the direction of misalignment of the first wire 11 relative to the third wire 13 and the direction of misalignment of the second wire 12 relative to the fourth wire 14 are opposite to each other. In other words, as shown in FIG. 3 , the nth turn of the third wire 13 is located to the upper left of the nth turn of the first wire 11, and the nth turn of the fourth wire 14 is located to the lower right of the nth turn of the second wire 12. In other words, the stray capacitance C1 between different turns occurs between the nth turn of the third wire 13 and the n-1th turn of the first wire 11, and the stray capacitance C2 between different turns occurs between the nth turn of the fourth wire 14 and the n+1th turn of the second wire 12.

[0041] As a result, the stray capacitance C1 between the first and second layers and the stray capacitance C2 between the third and fourth layers are generated in opposite directions. Unlike the technology described in Patent Document 1, the stray capacitances C1 and C2 are generated by two wires (the first wire 11 and the second wire 12, and the third wire 13 and the fourth wire 14) electrically connected in parallel, rather than being divided into the first and second halves of each wire turn. That is, for the nth turn of one signal line, stray capacitances C1 and C2 can be generated in both the n-1th and n+1th turns of the other signal line. Therefore, in the common mode choke coil 1, the bias in stray capacitance is reduced not only macroscopically, i.e., across the entire signal line, but also locally, specifically, on a turn-by-turn basis. This reduces the mode conversion characteristic up to high frequencies.

[0042] Figure 4 shows the frequency characteristics of the mode conversion characteristics of a common mode choke coil obtained by simulation. In Figure 4, (A) shows the characteristics of a common mode choke coil employing a two-layer winding called layer winding, as described in Patent Document 1 as a comparative example, (B) shows the characteristics of a common mode choke coil according to the first embodiment described in Patent Document 1 as a comparative example, and (C) shows the characteristics of a common mode choke coil having the configuration described with reference to Figures 1 to 3. These characteristics were obtained for a common mode choke coil with 10 wire turns.

[0043] As shown in Figure 4, the mode conversion characteristics (B) and (C) of the common mode choke coil according to the first embodiment described in Patent Document 1 and the common mode choke coil having the configuration described with reference to Figures 1 to 3 are reduced compared to the mode conversion characteristic (A) of the common mode choke coil employing a two-layer winding called layer winding described in Patent Document 1. Furthermore, it has been confirmed that the mode conversion characteristic (C) of the common mode choke coil having the configuration described with reference to Figures 1 to 3 is improved by approximately 20 dB compared to the mode conversion characteristic (B) of the common mode choke coil according to the first embodiment described in Patent Document 1.

[0044] Of these improvements, the improvement in the high frequency range is due to the reduction in the local imbalance in stray capacitance between different turns as described above, while the improvement in the low frequency range is due to the reduction in the difference in inductance between different signal lines.

[0045] In the common mode choke coil employing a two-layer winding known as layer winding, as described in Patent Document 1, and the common mode choke coil according to the first embodiment described in Patent Document 1, the first wire always constitutes the first layer, and the second wire always constitutes the second layer. In this case, the winding diameter of the wire is larger in the second layer, resulting in differences in the wire line length and distance from the core between the first and second wires, resulting in slight differences in inductance. On the other hand, in the common mode choke coil 1 having the configuration described with reference to Figures 1 to 3, one signal line is composed of the first wire 11 and the second wire 12, i.e., the innermost first layer and the outermost fourth layer, while the other signal line is composed of the third wire 13 and the fourth wire 14, i.e., the intermediate second and third layers. Therefore, on average, the differences in the wire line length and distance from the core are reduced, and the differences in inductance are also reduced. This allows the common mode choke coil 1 to reduce mode conversion characteristics in the low-frequency range.

[0046] In the common mode choke coil 1, the third wire 13 and the fourth wire 14, which respectively constitute the second and third intermediate layers, are connected between the third terminal electrode 23 and the fourth terminal electrode 24, so there is little need to consider stray capacitance (distributed capacitance). However, if the same turns of the third wire 13 and the fourth wire 14 are too far apart, the potential difference between the third wire 13 and the fourth wire 14 becomes significant, which may cause a stray capacitance problem. To avoid this problem, in the embodiment shown in FIG. 2, the same turns of the third wire 13 and the fourth wire 14 are adjacent to each other, counting from the first end 4, but the turn of the third wire 13 is located closer to the first end 4 than the same turn of the fourth wire 14. This positional relationship may be reversed, as shown in FIG. 5, which will be described below.

[0047] Fig. 5 shows a modified example of the common mode choke coil 1 shown in Fig. 2. Fig. 5 is a diagram corresponding to Fig. 2. In Fig. 5, elements corresponding to those shown in Fig. 2 are given the same reference numerals, and duplicated explanations will be omitted.

[0048] In the common mode choke coil 1a shown in Fig. 5, the winding pattern of the wires 11 to 14 is different from that of the common mode choke coil 1 shown in Fig. 2. In the winding pattern of the wires 11 to 14 shown in Fig. 2, there is no winding core or wire that stably supports the first turn 13-1 of the third wire 13, the twentieth turn 14-20 of the fourth wire 14, and the first turn 12-1 of the second wire 12, and they are left floating in the air. Therefore, it is difficult to stably wind the first turn 13-1 of the third wire 13, the twentieth turn 14-20 of the fourth wire 14, and the first turn 12-1 of the second wire 12 and maintain the wound positions.

[0049] 5, the first turn 13-1 of the third wire 13 is located on the winding core 3 closer to the first end 4 than the first turn 11-1 of the first wire 11. The twentieth turn 14-20 of the fourth wire 14 fits into a recess formed between the 19th turn 13-19 and the twentieth turn 13-20 of the third wire 13. Therefore, the wound positions of all turns of all wires 11-14 can be stably maintained.

[0050] Although the first turn 12-1 of the second wire 12 is shown in a state where it is partially suspended in the air, the first turn 12-1 of the second wire 12 may be fitted between the first turn 14-1 of the fourth wire 14 and the first flange 6. The first turn 14-1 of the fourth wire 14 is fitted into a recess formed between the first turn 11-1 of the first wire 11 and the first turn 13-1 of the third wire 13, and therefore its position can be stably maintained.

[0051] Such a winding mode shown in FIG. 5 is highly likely to be adopted in a practical winding process.

[0052] 5, the third wire 13 and the fourth wire 14 have the same turns adjacent to each other when counted from the first end 4, but the turn of the third wire 13 is located closer to the second end 5 than the same turn of the fourth wire 14. This positional relationship is the opposite of the positional relationship between the third wire 13 and the fourth wire 14 shown in FIG. 2. However, it goes without saying that the embodiment shown in FIG. 5 also maintains the same effects as the embodiment shown in FIG. 2.

[0053] 2 and the common mode choke coil 1a shown in Fig. 5, the first wire 11, the second wire 12, the third wire 13, and the fourth wire 14 are all circular in cross section and have the same outer diameter. This stabilizes the winding state of the upper wires relative to the lower wires, i.e., the upper third wire 13 relative to the lower first wire 11, the upper fourth wire 14 relative to the lower third wire 13, and the upper second wire 12 relative to the lower fourth wire.

[0054] Furthermore, the common mode choke coil 1 shown in Fig. 2 and the common mode choke coil 1a shown in Fig. 5 do not need to have a location where multiple wires cross, such as switching region C in the common mode choke coil 31a shown in Fig. 11. Therefore, compared to the common mode choke coil 31a shown in Fig. 11, the common mode choke coils 1 and 1a are easier to manufacture and are less likely to suffer from deterioration in wire quality, such as damage to the insulating coating layer 18 (see Fig. 8) of the wires 11 to 14.

[0055] Next, a common mode choke coil 1b according to a second embodiment disclosed in this specification will be described with reference to Figures 6 to 8. Figure 6 corresponds to Figure 1, and Figure 7 corresponds to Figure 2. In Figures 6 to 8, elements corresponding to those shown in Figures 1 and 2 are given the same reference numerals, and duplicate explanations will be omitted.

[0056] Common mode choke coil 1b is characterized by having three wires. Simply put, common mode choke coil 1b according to the second embodiment is characterized in that the functions of third wire 13 and fourth wire 14 in common mode choke coil 1 according to the first embodiment are performed by third wire 13 alone. Therefore, according to the second embodiment, the wire winding process can be further simplified compared to the first embodiment.

[0057] Common mode choke coil 1b includes a core 2 and three wires, namely, a first wire 11, a second wire 12, and a third wire 13. In order to clearly distinguish first wire 11 and second wire 12 from third wire 13 in Fig. 7, the cross sections of first wire 11 and second wire 12 are shown in white, and the cross section of third wire 13 is shaded.

[0058] Similar to the core 2 in the first embodiment, the core 2 has a winding core 3, a first flange 6 provided on a first end 4 side in the axial direction of the winding core 3, and a second flange 7 provided on a second end 5 side opposite to the first end 4 side. The first wire 11, the second wire 12, and the third wire 13 are spirally wound around the winding core 3 from the first end 4 side toward the second end 5 side with substantially the same number of turns and in parallel to each other.

[0059] As in the case of the core 2 in the first embodiment, the first flange 6 is provided with a first terminal electrode 21 and a third terminal electrode 23, and the second flange 7 is provided with a second terminal electrode 22 and a fourth terminal electrode 24. In Fig. 7, the terminal electrodes 21 to 24 are not shown.

[0060] One end of each of the first wire 11 and the second wire 12 is connected to a first terminal electrode 21, and the other end of each of the first wire 11 and the second wire 12 is connected to a second terminal electrode 22. One end of the third wire 13 is connected to a third terminal electrode 23, and the other end of the third wire 13 is connected to a fourth terminal electrode 24.

[0061] The common mode choke coil 1b may also be provided with a top plate equivalent to the top plate 45 shown in FIG.

[0062] 7, first, the first wire 11 is wound around the winding core 3 to form a first layer. Next, the third wire 13 is wound around the winding core 3 to form a second layer on the outer periphery of the first layer, with a portion of the third wire 11, more precisely, a portion of its cross section, fitting into a recess formed between adjacent turns of the first wire 11. Next, the second wire 12 is wound around the outer periphery of the second layer to form a third layer, with a portion of the third wire 12, more precisely, a portion of its cross section, fitting into a recess formed between adjacent turns of the third wire 13.

[0063] The first wire 11 constituting the first layer and the third wire 13 constituting the second layer are adjacent to each other with the same numbered turns counted from the first end 4 side of the winding core 3, but the turn of the first wire 11 is located closer to the second end 5 side of the winding core 3 than the same numbered turn of the third wire 13.

[0064] Furthermore, the second wire 12 constituting the third layer and the third wire 13 constituting the second layer have the same turns adjacent to each other when counted from the first end 4 of the winding core 3, but the turn of the second wire 12 is located closer to the first end 4 of the winding core 3 than the same turn of the third wire 13. The first turn 12-1 of the second wire 12 is located on the first end 4 side of the first turn 11-1 of the first wire 11, on the winding core 3. This winding pattern, like the winding pattern shown in FIG. 5, is likely to be adopted in a practical winding process.

[0065] In the common mode choke coil 1b according to the second embodiment, the stray capacitance between the first and second layers and the stray capacitance between the second and third layers occur in opposite directions. As in the first embodiment, these two types of stray capacitance, which occur in opposite directions, are generated using two wires (the first wire 11 and the second wire 12) electrically connected in parallel. That is, for the nth turn of one signal line, stray capacitances C1 and C2 can be generated for both the n-1th and n+1th turns of the other signal line. Therefore, in the common mode choke coil 1b, the bias in stray capacitance is reduced not only macroscopically, i.e., for the entire signal line, but also locally, specifically, for each turn. This reduces the mode conversion characteristic up to the high frequency range.

[0066] The common mode choke coil 1b according to the second embodiment includes a first inductor formed by a first wire 11 and a second wire 12 connected between a first terminal electrode 21 and a second terminal electrode 22, and a second inductor formed by a third wire 13 connected between a third terminal electrode 23 and a fourth terminal electrode 24. In this case, if the first wire 11, the second wire 12, and the third wire 13 are formed from wires of the same specifications, a difference will occur between the DC resistance of the first inductor and the DC resistance of the second inductor.

[0067] By taking appropriate measures to address the difference in DC resistance as described above, it is possible to further improve the characteristics of the common mode choke coil 1b. As a measure to address this, it is preferable to employ the following configuration in the second embodiment.

[0068] 8, the first wire 11, the second wire 12, and the third wire 13 each include a central conductor 17 made of a conductor such as copper and having a circular cross section, and an electrically insulating coating layer 18 that covers the circumferential surface of the central conductor 17. The diameter of the central conductor 17 of the third wire 13 is approximately √2 times the diameter of the central conductor 17 of each of the first wire 11 and the second wire 12, i.e., 1.3 times or more and 1.5 times or less.

[0069] By adopting the above-described configuration, the total cross-sectional area of the central conductor 17 of the first wire 11 and the central conductor 17 of the second wire 12 can be made equal or nearly equal to the cross-sectional area of the central conductor 17 of the third wire 13. As a result, the difference in DC resistance between the first inductor formed by the first wire 11 and the second wire 12 and the second inductor formed by the third wire 13 can be eliminated or nearly eliminated.

[0070] In common mode choke coil 1b, first wire 11, second wire 12, and third wire 13 are all circular in cross section and have the same outer diameter. As in the first embodiment, this contributes to stabilizing the winding state of the upper wires relative to the lower wires, i.e., the upper third wire 13 relative to the lower first wire 11, and the upper second wire 12 relative to the lower third wire 13.

[0071] Furthermore, in the case of common mode choke coil 1b, as in the case of common mode choke coil 1 shown in Fig. 2 and common mode choke coil 1a shown in Fig. 5, there is no need to provide a location where multiple wires cross, such as switching region C in common mode choke coil 31a shown in Fig. 11. Therefore, compared to common mode choke coil 31a shown in Fig. 11, common mode choke coil 1b is easier to manufacture and is less likely to suffer from deterioration in wire quality, such as damage to insulating coating layer 18 of wires 11-13.

[0072] As described above, in the common mode choke coil 1 shown in FIG. 2 and the common mode choke coil 1a shown in FIG. 5, the first wire 11 and the third wire 13 have adjacent turns of the same order when counted from the first end 4, but the turn of the first wire 11 is located closer to the second end 5 than the turn of the third wire 13 of the same order, and the second wire 12 and the fourth wire 14 have adjacent turns of the same order when counted from the first end 4, but the turn of the second wire 12 is located closer to the first end 4 than the turn of the fourth wire 14 of the same order.

[0073] In addition, in the common mode choke coil 1b shown in Figure 7, the first wire 11 and the third wire 13 have adjacent turns of the same order when counted from the first end 4, but the turn of the first wire 11 is located closer to the second end 5 than the turn of the third wire 13 of the same order, and the second wire 12 and the third wire 13 have adjacent turns of the same order when counted from the first end 4, but the turn of the second wire 12 is located closer to the first end 4 than the turn of the third wire 13 of the same order.

[0074] That is, in each of the common mode choke coils 1, 1a, and 1b, two regions in which the positional relationship of the two paired wires forming adjacent layers is reversed are stacked in a direction perpendicular to the axial direction of the winding core. Therefore, compared to the coil described in Patent Document 1, the degree of uneven distribution of the distributed capacitance is lower, and the mode conversion characteristics can be reduced up to a higher frequency range.

[0075] Furthermore, in all of the common mode choke coils 1, 1a, and 1b, a configuration is adopted in which the turns of the two wires that form adjacent layers and form a pair are adjacent to each other, but the turn of one wire is shifted by one turn from the turn of the other wire that is the same turn, as shown in Figures 2, 5, and 7. By adopting a configuration in which the turns are shifted by one turn in this way, the stray capacitance that occurs between the two wires can be kept to a minimum.

[0076] child invention of The first phase of In this case, for two wires that form adjacent layers and form a pair, the same turns are not shifted by just one turn, but by two or more turns. May be That is, for example, referring to FIG. 1, a configuration is adopted in which a predetermined turn of the first wire 11 is shifted by two or more turns toward the second end 5 from a turn of the third wire 13 that is the same as the turn of the first wire 11 when counted from the first end 4 side, and a predetermined turn of the second wire 12 is shifted by two or more turns toward the first end 4 from a turn of the fourth wire 14 that is the same as the turn of the second wire 12 when counted from the first end 4 side. May be . Generally speaking, in the first aspect of this invention, a given turn of the first wire is shifted more than s turns toward the second end from a turn of the third wire that is in the same position as the turn of the first wire when counted from the first end, and a given turn of the second wire is shifted more than t turns toward the first end from a turn of the fourth wire that is in the same position as the turn of the second wire when counted from the first end (where s and t are natural numbers, and one of s and t is 2 and the other is 1).

[0077] Furthermore, in the common mode choke coils 1 and 1a, the amount of turn offset between the first wire 11 and the third wire 13 and the amount of turn offset between the second wire 12 and the fourth wire 14 may be different from each other. Similarly, in the common mode choke coil 1b, the amount of turn offset between the first wire 11 and the third wire 13 and the amount of turn offset between the second wire 12 and the third wire 13 may be different from each other.

[0078] Although the present invention has been described above with reference to the illustrated embodiment, various other modifications are possible within the scope of the present invention.

[0079] For example, the number of turns of the wire provided in the common mode choke coil can be increased or decreased as desired.

[0080] Furthermore, the direction of counting the number of turns employed in the description of the embodiment may be reversed.

[0081] Furthermore, the plurality of wires provided in the common mode choke coil may have some crossing portions or twisted wound portions where the wires are twisted together.

[0082] Furthermore, the illustrated embodiments are merely examples, and partial substitution or combination of configurations is possible between different embodiments. [Explanation of symbols]

[0083] 1,1a,1b Common mode choke coil 2 cores 3 Winding core 4 1st end 5 2nd end 6 First flange 7 Second flange 11 First Wire 12 Second Wire 13 Third Wire 14 4th wire 17 Center conductor 18 Insulating coating layer 21 1st terminal electrode 22 2nd terminal electrode 23 3rd terminal electrode 24 4th terminal electrode

Claims

1. a core having a winding core portion, a first flange portion provided on a first end side in the axial direction of the winding core portion, and a second flange portion provided on a second end side opposite to the first end side in the axial direction of the winding core portion; a first wire, a second wire, a third wire, and a fourth wire wound spirally around the winding core in parallel with each other; a first terminal electrode and a third terminal electrode provided on the first flange portion; a second terminal electrode and a fourth terminal electrode provided on the second flange portion; Equipped with one end of each of the first wire and the second wire is connected to the first terminal electrode, and the other end of each of the first wire and the second wire is connected to the second terminal electrode; one end of each of the third wire and the fourth wire is connected to the third terminal electrode, and the other end of each of the third wire and the fourth wire is connected to the fourth terminal electrode; the first wire is wound around the winding core to form a first layer; the third wire is wound to form a second layer on the outer circumferential side of the first layer, the fourth wire is wound to form a third layer on the outer circumferential side of the second layer, the second wire is wound to form a fourth layer on the outer circumferential side of the third layer, A predetermined turn of the first wire is shifted by s turns or more toward the second end from a turn of the third wire that is the same as the turn of the first wire when counted from the first end side as the corresponding turn of the first wire, and a predetermined turn of the second wire is shifted by t turns or more toward the first end from a turn of the fourth wire that is the same as the turn of the second wire when counted from the first end side as the corresponding turn of the second wire (where s and t are natural numbers, and one of s and t is 2 and the other is 1). Common mode choke coil.

2. A common mode choke coil as described in claim 1, wherein the first wire, the second wire, the third wire and the fourth wire are wound around the winding core portion with substantially the same number of turns as each other.

3. The first wire and the third wire are arranged such that, counting from the first end, the same numbered turns of each wire are adjacent to each other, and the turn of the first wire is located closer to the second end than the same numbered turn of the third wire; The second wire and the fourth wire have the same numbered turns adjacent to each other when counted from the first end, and the turn of the second wire is located closer to the first end than the same numbered turn of the fourth wire.

3. The common mode choke coil according to claim 1 or 2.

4. A common mode choke coil as described in Claim 3, wherein the third wire and the fourth wire have the same numbered turns adjacent to each other when counted from the first end, but the turn of the third wire is located closer to the first end than the same numbered turn of the fourth wire.

5. A common mode choke coil as described in Claim 3, wherein the third wire and the fourth wire have the same numbered turns adjacent to each other when counted from the first end, but the turn of the third wire is located closer to the second end than the same numbered turn of the fourth wire.

6. A common mode choke coil as described in any one of claims 1 to 5, wherein the first wire, the second wire, the third wire and the fourth wire are all circular in cross section and have the same outer diameter.

7. A common mode choke coil as described in claim 6, wherein the first wire, the second wire, the third wire and the fourth wire are all made of conductors and have a central conductor with a circular cross section and an electrically insulating insulating coating layer covering the circumferential surface of the central conductor, the central conductors of the first wire, the second wire, the third wire and the fourth wire each have the same outer shape, and the insulating coating layers of the first wire, the second wire, the third wire and the fourth wire each have the same thickness.

8. A common mode choke coil as described in claim 3, wherein the amount of deviation between the turn of the first wire and the turn of the third wire that is the same as that turn, and the amount of deviation between the turn of the second wire and the turn of the fourth wire that is the same as that turn, are made equal to each other.

9. A common mode choke coil as described in claim 3, wherein the amount of deviation between the turn of the first wire and the turn of the third wire that is the same as that turn is different from the amount of deviation between the turn of the second wire and the turn of the fourth wire that is the same as that turn.

10. A core having a winding core portion, a first flange portion provided on a first end side of the winding core portion in the axial direction, and a second flange portion provided on a second end side opposite to the first end side of the winding core portion in the axial direction; a first wire, a second wire, and a third wire wound spirally around the winding core in parallel with each other; a first terminal electrode and a third terminal electrode provided on the first flange portion; a second terminal electrode and a fourth terminal electrode provided on the second flange portion; Equipped with one end of each of the first wire and the second wire is connected to the first terminal electrode, and the other end of each of the first wire and the second wire is connected to the second terminal electrode; one end of the third wire is connected to the third terminal electrode, and the other end of the third wire is connected to the fourth terminal electrode; the first wire is wound around the winding core to form a first layer; the third wire is wound to form a second layer on the outer circumferential side of the first layer, the second wire is wound to form a third layer on the outer circumferential side of the second layer, The first wire and the third wire are configured such that a certain turn of the first wire, counted from the first end, is shifted toward the second end with respect to a turn of the third wire that is the same as the certain turn of the first wire, The second wire and the third wire are configured such that a certain turn of the second wire, counted from the first end, is shifted toward the first end with respect to a turn of the third wire that is the same as the certain turn of the second wire. Common mode choke coil.

11. The first wire and the third wire have a plurality of turns, and a certain turn of the first wire counted from the first end side is shifted toward the second end side from the turn of the third wire that is the same as the turn in question, The second wire and the third wire have a plurality of turns, and a certain turn of the second wire, counted from the first end, is shifted toward the first end with respect to a turn of the third wire that is the same as the certain turn of the second wire. The common mode choke coil according to claim 10.

12. The first wire and the third wire are such that, for substantially all turns, a certain turn of the first wire, counted from the first end side, is shifted toward the second end side from the turn of the third wire that is the same as the turn in question, In substantially all turns of the second wire and the third wire, a certain turn of the second wire counted from the first end side is shifted toward the first end side with respect to a turn of the third wire that is the same as the certain turn of the second wire, The common mode choke coil according to claim 11.

13. A common mode choke coil as described in claim 11 or 12, wherein the amount of deviation between the turn of the first wire and the turn of the third wire that is the same number as that turn, and the amount of deviation between the turn of the second wire and the turn of the third wire that is the same number as that turn, are made equal to each other.

14. A common mode choke coil as described in any one of claims 11 to 13, wherein the amount of deviation between the turn of the first wire and the turn of the third wire that is the same as that turn is different from the amount of deviation between the turn of the second wire and the turn of the third wire that is the same as that turn.

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