common mode choke

Abstract

The end portions of the first and second lines of the common mode choke coil of the present application are connected to the first and second terminal electrodes, the end portions of the third and fourth lines are connected to the third and fourth terminal electrodes, at least a portion of the first, third, and fourth lines and the second line are wound around the winding core portion to form the first, second, third, and fourth layers, or the end portions of the first and second lines are connected to the first and second terminal electrodes, the end portion of the third line is connected to the third and fourth terminal electrodes, and at least a portion of the first, third, and second lines are wound around the winding core portion to form the first, second, and third layers.

Description

[0001] This application is a divisional application of application number 202010473951.6, filed on May 29, 2020, entitled "Common Mode Choke". Technical Field

[0002] This disclosure relates to common mode chokes, and more particularly to a wound common mode choke having a structure in which multiple wires are wound on a core. Background Technology

[0003] Reference Figure 9 as well as Figure 10 The typical structure of the common-mode choke 31 will be described.

[0004] like Figure 9 As shown, the common-mode choke 31 includes a core 32 and a first wire 33 and a second wire 34 that respectively constitute an inductor. The common-mode choke 31 may also include a top plate 45.

[0005] The core portion 32 has a core portion 35, a first flange portion 36 disposed on the side of a first end 38 in the axial direction of the core portion 35, and a second flange portion 37 disposed on the side of a second end 39 opposite to the side of the first end 38.

[0006] A first terminal electrode 41 and a third terminal electrode 43 are provided on the first flange portion 36, and a second terminal electrode 42 and a fourth terminal electrode 44 are provided on the second flange portion 37. Furthermore, based on the positions of the terminal electrodes 41 to 44, it can be known that... Figure 9 The common mode choke 31 is illustrated in a position where the mounting surface facing the mounting substrate is facing upwards.

[0007] The first wire 33 and the second wire 34 are wound in a spiral shape in parallel around the core portion 35 from the first end 38 side toward the second end 39 side. The end of the first wire 33 is connected to the first terminal electrode 41 and the second terminal electrode 42, respectively, and the end of the second wire 34 is connected to the third terminal electrode 43 and the fourth terminal electrode 44, respectively.

[0008] For the common-mode choke 31 with the structure described above, the following is given: Figure 10 The equivalent circuit is shown. Figure 10 In China, for the sake of Figure 9 The elements shown are labeled with the same reference numerals as those in the attached drawings.

[0009] Reference Figure 10 The common-mode choke 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.

[0010] Although Figure 9 It is not explicitly stated, but the first wire 33 is wound around the periphery of the core portion 35 to form a first layer, and the second wire 34 is wound around the recess between adjacent turns of the first wire 33 so that a portion of it is embedded and forms a second layer on the outer periphery of the first layer. In this way, the first inductor 46 and the second inductor 47 are magnetically coupled to each other.

[0011] In the common-mode choke 31 described above, if the frequency of the input signal increases, the proportion of the input differential signal component that is converted into common-mode noise and output, i.e., the mode switching characteristic, increases relative to the input differential signal component. For example, in Japanese Patent Application Publication No. 2014-120730 (Patent Document 1), the cause of this problem is cited as the imbalance of stray capacitances (distributed capacitances) generated between different turns of the first line 33 and the second line 34.

[0012] Therefore, as Figure 11 As shown, in the common mode choke 31a described in Patent Document 1, the following winding method of lines 33 and 34 is adopted.

[0013] In addition, Figure 11 In the diagram, a shading line is applied to the section representing the first line 33 to clearly distinguish it from the second line 34. Additionally, in... Figure 11 The cross-sections of the first line 33 and the second line 34 shown are marked with the number of turns “1” to “12”, starting from the side of the first end 38 where the first flange portion 36 of the core portion 35 is located.

[0014] exist Figure 11 In the diagram, solid lines schematically show portions of the first line 33 and the second line 34 wound around the core portion 35, located near the front of the core portion 35; dashed lines schematically show portions obscured by the core portion 35. Furthermore, in... Figure 11 The entirety of each portion of line 33 and line 34, the portion located near the front of the core portion 35, and the portion obscured by the core portion 35, is not shown in the figure.

[0015] Reference Figure 11 When classifying based on the winding states of the first thread 33 and the second thread 34, the following exists:

[0016] (1) The turns of the same number in the first line 33 and the second line 34 are adjacent to each other and the first line 33 is located in the first winding area A, which is closer to the first end 38 than the second line 34.

[0017] (2) The turns with the same number in the first line 33 and the second line 34 are adjacent to each other, and the first line 33 is located in the second winding area B, which is closer to the second end 39 than the second line 34.

[0018] (3) The switching region C is located between the first winding region A and the second winding region B, and the positional relationship between the turns of the first line 33 and the turns of the second line 34 is switched due to the intersection of the first line 33 and the second line 34.

[0019] Moreover, these first winding area A, switching area C and second winding area B are arranged in this order along the axial direction of the core portion 35.

[0020] In the technology described in Patent Document 1, when addressing the problem of significant variations in mode switching characteristics, to balance the stray capacitance (distributed capacitance) generated between different turns of the first line 33 and the second line 34, the winding structures of the first line 33 and the second line 34 in the first winding region A and the first line 33 and the second line 34 in the second winding region B are symmetrical with respect to the center line CL of the switching region C. In other words, the number of turns of each of the first line 33 and the second line 34 in the first winding region A and the number of turns of each of the first line 33 and the second line 34 in the second winding region B are equal.

[0021] Therefore, since the different inter-turn capacitances are generated evenly relative to the first line 33 and the second line 34, the impedance imbalance between the first line 33 and the second line 34 can be suppressed, the mode switching characteristics are reduced, and a high-quality common-mode choke can be achieved.

[0022] Patent Document 1: Japanese Patent Application Publication No. 2014-120730

[0023] However, according to the technology described in Patent Document 1, the mode switching characteristic cannot be completely reduced to zero. For example, since the circuit formed by the common-mode choke 31a is divided into two parts, a first half and a second half, relative to the signal travel direction, macroscopically, the bias of stray capacitance between different turns is eliminated. However, locally, for example, when only the first half or the second half is observed, stray capacitance between different turns is generated. Therefore, as will be described later... Figure 4 As shown, the inventors of this invention discovered that the mode switching characteristics gradually deteriorate in the high-frequency range. Summary of the Invention

[0024] Therefore, the object of this disclosure is, for example, to provide a common-mode choke that includes a structure capable of reducing local bias in the generation of stray capacitance between different turns and further reducing mode switching characteristics, and capable of significantly improving the degree of freedom in the generation of stray capacitance between different turns.

[0025] One aspect of the common-mode choke disclosed herein includes: a core having a wound core portion, a first flange portion disposed on a first end side in the axial direction of the wound core portion, and a second flange portion disposed on a second end side in the axial direction of the wound core portion opposite to the first end side; a first wire, a second wire, a third wire, and a fourth wire being wound into a spiral shape around the wound core portion; a first terminal electrode and a third terminal electrode disposed on the first flange portion; and a second terminal electrode and a fourth terminal electrode disposed on the second flange portion.

[0026] The first end of each of the first and second wires is connected to the first terminal electrode, the second end of each of the first and second wires is connected to the second terminal electrode, the first end of each of the third and fourth wires is connected to the third terminal electrode, and the second end of each of the third and fourth wires is connected to the fourth terminal electrode.

[0027] At least a portion of the first wire is wound around the core portion to form a first layer, at least a portion of the third wire is wound in the recesses formed between adjacent turns of the first wire to form a second layer that is the outer periphery of the first layer, at least a portion of the fourth wire is wound in the recesses formed between adjacent turns of the third wire to form a third layer that is the outer periphery of the second layer, and at least a portion of the second wire is wound in the recesses formed between adjacent turns of the fourth wire to form a fourth layer that is the outer periphery of the third layer.

[0028] In addition, another embodiment of the common-mode choke disclosed herein includes: a core having a wound core portion, a first flange portion disposed on a first end side in the axial direction of the wound core portion, and a second flange portion disposed on a second end side opposite to the first end side in the axial direction of the wound core portion; a first wire, a second wire, and a third wire being wound into a spiral shape around the wound core portion; a first terminal electrode and a third terminal electrode disposed on the first flange portion; and a second terminal electrode and a fourth terminal electrode disposed on the second flange portion.

[0029] The first end of each of the first and second wires is connected to the first terminal electrode, the second end of each of the first and second wires is connected to the second terminal electrode, the first end of the third wire is connected to the third terminal electrode, and the second end of the third wire is connected to the fourth terminal electrode.

[0030] At least a portion of the first wire is wound around the core portion to form a first layer, at least a portion of the third wire is wound in the recesses formed between adjacent turns of the first wire to form a second layer that becomes the outer periphery of the first layer, and at least a portion of the second wire is wound in the recesses formed between adjacent turns of the third wire to form a third layer that becomes the outer periphery of the second layer.

[0031] In the technology described in Patent Document 1, a first winding region and a second winding region with opposite positional relationships of two pairs of wires are arranged in the axial direction of the core portion. In contrast, in the above method, simply put, a structure is adopted in which the region corresponding to the first winding region and the region corresponding to the second winding region are stacked in a direction orthogonal to the axial direction of the core portion.

[0032] According to the above method, since multiple destinations for the generation of stray capacitance between different turns can be set for a certain turn of the first inductor or the second inductor composed of 4 or 3 wires, the degree of freedom in the generation of stray capacitance between different turns can be significantly improved. Attached Figure Description

[0033] Figure 1 This is a top view showing the appearance of the common mode choke 1 of the first embodiment from the mounting side.

[0034] Figure 2 It is a schematic representation Figure 1 A cross-sectional view of the winding state of the first line 11 to the fourth line 14 in the common mode choke 1 shown.

[0035] Figure 3 In order to Figure 2 The cross-sectional view shown is an enlarged view of a portion of the first line 11 to the fourth line 14, illustrating the stray capacitances C1 and C2 generated between the first line 11 and the fourth line 14.

[0036] Figure 4 The graph shows the frequency characteristics of the mode switching characteristics of the common mode choke. (A) shows the characteristics of the common mode choke with a double-layer winding, as described in Patent Document 1, which is used as a comparative example. (B) shows the characteristics of the common mode choke of the first embodiment described in Patent Document 1, which is used as a comparative example. (C) shows the characteristics of the common mode choke as an embodiment.

[0037] Figure 5 It is a schematic representation of as Figure 2 A cross-sectional view of the first line 11 to the fourth line 14 in the winding state of a modified example of the common mode choke 1a.

[0038] Figure 6 This is a top view showing the appearance of the common mode choke 1b of the second embodiment from the mounting side.

[0039] Figure 7 It is a schematic representation Figure 6 A cross-sectional view of the winding state of the first line 11 to the third line 13 in the common mode choke 1b shown.

[0040] Figure 8 In order to Figure 7 The enlarged cross-sectional view of a portion of the first line 11 to the third line 13 is shown to illustrate the dimensional relationship of the center conductor 17 of the first line 11 to the third line 13 and the insulating covering layer 18.

[0041] Figure 9 This is a perspective view showing the appearance of a typical common-mode choke 31 with the mounting surface facing upwards.

[0042] Figure 10 yes Figure 9 The equivalent circuit diagram of the common-mode choke 31 is shown.

[0043] Figure 11 It is a cross-sectional view schematically showing the winding state of the first wire 33 and the second wire 34 in the common mode choke 31a described in Patent Document 1. Detailed Implementation

[0044] exist Figure 1 The image shows the common-mode choke 1 from the first embodiment. Figure 1 The common-mode choke 1 shown has a core 2 and four wires that respectively constitute an inductor, namely, a first wire 11, a second wire 12, a third wire 13, and a fourth wire 14. Figure 2 In the middle, a schematic cross-sectional view is shown. Figure 1 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 1 is shown. Figure 2 In order to clearly distinguish the first line 11 and the second line 12 from the third line 13 and the fourth line 14, the cross-sections of the first line 11 and the second line 12 are represented by hollow lines, and the cross-sections of the third line 13 and the fourth line 14 are shaded.

[0045] 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 is generally quadrilateral in cross-section. Wires 11 to 14 are, for example, made of copper wire covered with insulation, and are circular in cross-section with the same outer diameter. Furthermore, the materials and shapes of the core 2, as well as the materials, shapes, and outer diameters of the wires 11 to 14, are not limited to those illustrated herein.

[0046] The core portion 2 has a core portion 3, a first flange portion 6 disposed on the side of a first end 4 in the axial direction of the core portion 3, and a second flange portion 7 disposed on the side of a second end 5 opposite to the side of the first end 4. The first thread 11, the second thread 12, the third thread 13, and the fourth thread 14 are wound in a spiral shape in parallel around the core portion 3 from the side of the first end 4 toward the side of the second end 5 with substantially the same number of turns. Furthermore, the term "substantially the same number of turns" is used because the positions of the beginning or end of the winding of each of the threads 11 to 14 on the core portion 3 are slightly offset from each other.

[0047] A first terminal electrode 21 and a third terminal electrode 23 are provided on the first flange portion 6, and a second terminal electrode 22 and a fourth terminal electrode 24 are provided on the second flange portion 7. The terminal electrodes 21 to 24 are provided, for example, by baking a conductive paste, electroplating a conductive metal, or bonding a metal plate with an adhesive. Furthermore, Figure 1 Common mode choke 1 is shown from the mounting side. Additionally, in Figure 2 The diagrams of terminal electrodes 21 to 24 are omitted in the text.

[0048] The first end 4 of each of the first wires 11 and 12 is connected to the first terminal electrode 21, and the second end 5 of each of the first wires 11 and 12 is connected to the second terminal electrode 22. The first end 4 of each of the third wires 13 and 14 is connected to the third terminal electrode 23, and the second end 5 of each of the third wires 13 and 14 is connected to the fourth terminal electrode 24. These connections are made, for example, by thermoforming or laser welding.

[0049] Common mode choke 1 can also have equivalent to Figure 9 The common-mode choke 31 shown includes a top plate 45. The top plate is the same as the core 2, and is made of, for example, alumina (a non-magnetic material), Ni-Zn ferrite (a magnetic material), or resin. When both the core 2 and the top plate are made of magnetic materials, by positioning the top plate between the first flange 6 and the second flange 7, the core 2 and the top plate cooperate to form a closed magnetic circuit.

[0050] Main reference Figure 2First, a first thread 11 is wound around the core portion 3 to form a first layer. Next, a third thread 13 is wound around a recess formed between adjacent turns of the first thread 11, so that a portion of its cross-section is embedded, forming a second layer that becomes the outer periphery of the first layer. Next, a fourth thread 14 is wound around a recess formed between adjacent turns of the third thread 13, so that a portion of its cross-section is embedded, forming a third layer that becomes the outer periphery of the second layer. Finally, a second thread 12 is wound around a recess formed between adjacent turns of the fourth thread 14, so that a portion of its cross-section is embedded, forming a fourth layer that becomes the outer periphery of the third layer.

[0051] exist Figure 2 In the cross-section of each of the first line 11, the second line 12, the third line 13, and the fourth line 14, the number of turns, "1" to "20", is marked starting from the first end 4 side of the core portion 3. (The following will be discussed...) Figure 5 as well as Figure 7 In the middle, the number of turns within the cross section of the line is also marked.

[0052] Regarding the number of turns mentioned above, the first line 11 constituting the first layer and the third line 13 constituting the second layer have turns with the same number that are adjacent to each other, starting from the first end 4 side of the core portion 3, and the portion of the first line 11 is located closer to the second end 5 side of the core portion 3 than the portion of the third line 13. That is, when n is set to a natural number from 2 to 20, the nth turn of the third line 13 is adjacent to the (n-1)th turn of the first line 11.

[0053] Furthermore, the second thread 12 constituting the fourth layer and the fourth thread 14 constituting the third layer have turns with the same number that are adjacent to each other, starting from the first end 4 side of the core portion 3, and the portion of the second thread 12 is located closer to the first end 4 side of the core portion 3 than the portion of the fourth thread 14. That is, when n is set to a natural number from 1 to 19, the nth turn of the fourth thread 14 is adjacent to the (n+1)th turn of the second thread 12.

[0054] Therefore, as Figure 3 As shown, stray capacitance C1 is generated between different turns of the first line 11 connected to the first terminal electrode 21 and the second terminal electrode 22, and the third line 13 connected to the third terminal electrode 23 and the fourth terminal electrode 24. Similarly, stray capacitance C2 is generated between different turns of the second line 12 connected to the first terminal electrode 21 and the second terminal electrode 22, and the fourth line 14 connected to the third terminal electrode 23 and the fourth terminal electrode 24. Furthermore, since the first line 11 and the second line 12, the third line 13, and the fourth line 14 are each connected to the same terminal electrode, they are electrically connected in parallel and form identical signal lines on the differential signal line.

[0055] If we consider the deviation of the turns between the first line 11 and the third line 13, and the deviation of the turns between the second line 12 and the fourth line 14, which are the causes of the aforementioned stray capacitances C1 and C2, then the direction of deviation of the first line 11 relative to the third line 13 is opposite to the direction of deviation of the second line 12 relative to the fourth line 14. In other words, as Figure 3 As shown, the nth turn of the third line 13 is located to the upper left of the nth turn of the first line 11, and the nth turn of the fourth line 14 is located to the lower right of the nth turn of the second line 12. That is, the stray capacitance C1 between different turns is generated between the nth turn of the third line 13 and the (n-1)th turn of the first line 11, and the stray capacitance C2 between different turns is generated between the nth turn of the fourth line 14 and the (n+1)th turn of the second line 12.

[0056] 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. Thus, instead of dividing the stray capacitances C1 and C2 into the first and second halves of each line's turns as described in Patent Document 1, they are generated using two lines connected in parallel (first line 11 and second line 12, third line 13 and fourth line 14). That is, for the nth turn of one signal line, stray capacitances C1 and C2 can be generated on both the (n-1)th and (n+1)th turns of another signal line. Therefore, in the common-mode choke 1, stray capacitance bias can be reduced not only macroscopically (i.e., the signal line as a whole) but also locally, specifically on a turn-by-turn basis. Because of this, mode switching characteristics can be reduced even in the high-frequency range.

[0057] exist Figure 4 The frequency characteristics of the mode switching performance of the common-mode choke, obtained through simulation, are shown in the figure. Figure 4 In the diagram, (A) represents the characteristics of a common-mode choke using a double-layer winding, as described in Patent Document 1, as a comparative example; (B) represents the characteristics of a common-mode choke in the first embodiment described in Patent Document 1, as a comparative example; and (C) represents the characteristics of a common-mode choke as an embodiment. These characteristics were derived for a common-mode choke with 10 turns.

[0058] like Figure 4 As shown, compared to the mode switching characteristics (A) of the common-mode choke using a double-layer winding, referred to as a layered winding, as described in Patent Document 1, the mode switching characteristics (B) and (C) of each of the common-mode chokes in the first embodiment described in Patent Document 1 and the common-mode chokes as embodiments of the present invention are reduced. Furthermore, the mode switching characteristics (C) of the common-mode choke as an embodiment of the present invention are confirmed to have an improvement effect of approximately 20 dB compared to the mode switching characteristics (B) of the common-mode choke in the first embodiment described in Patent Document 1.

[0059] Furthermore, the improvement in the high-frequency range is due to the reduction of local bias in the stray capacitance between different turns, while the improvement in the low-frequency range is due to the reduction in the difference in inductance between different signal lines.

[0060] In the common-mode choke described in Patent Document 1, which uses a double-layer winding and is referred to as a layered winding, and in the common-mode choke of the first embodiment described in Patent Document 1, the first wire constitutes the first layer and the second wire constitutes the second layer. In this case, the winding diameter of the second layer wire is larger, resulting in differences in wire length and distance from the core between the first and second wires, leading to a slight difference in inductance. On the other hand, in the common-mode choke 1, which is an embodiment of the present invention, since 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), and the other signal line is composed of the third wire 13 and the fourth wire 14 (i.e., the middle second and third layers), the average difference in wire length and distance from the core is reduced, and the difference in inductance is also reduced. Therefore, in the common-mode choke 1, which is an embodiment of the present invention, mode switching characteristics in the low-frequency range can also be reduced.

[0061] Furthermore, in the common-mode choke 1, since the third wire 13 and the fourth wire 14, which constitute the intermediate second and third layers respectively, are both connected between the third terminal electrode 23 and the fourth terminal electrode 24, stray capacitance (distributed capacitance) is almost negligible. However, if the turns with the same number in each 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 cannot be ignored, and a problem of stray capacitance may arise. To avoid this problem, in Figure 2 In the illustrated embodiment, the third line 13 and the fourth line 14 have turns with the same number counting from the first end 4 that are adjacent to each other, and the third line 13 is located on the portion of the fourth line 14 closer to the first end 4 than the fourth line 14. As described below... Figure 5 As shown, this positional relationship can also be reversed.

[0062] exist Figure 5 In, it is shown Figure 2 The common-mode choke 1 shown is a modified example. Figure 5 It corresponds to Figure 2 The image. In Figure 5 In China, for the sake of Figure 2 Elements shown that correspond to each other are labeled with the same reference numerals as those in the accompanying drawings, and repeated descriptions are omitted.

[0063] exist Figure 5 In the common-mode choke 1a shown, the winding method of wires 11 to 14 is the same as... Figure 2The case of common-mode choke 1 shown is different. Figure 2 In the winding method shown, the core portions or wires of the first turn 13-1 of the third wire 13, the 20th turn 14-20 of the fourth wire 14, and the first turn 12-1 of the second wire 12 are not stably received, and thus remain suspended in the air. Therefore, it is difficult to wind the first turn 13-1 of the third wire 13, the 20th turn 14-20 of the fourth wire 14, and the first turn 12-1 of the second wire 12 in a stable state and maintain the winding position.

[0064] In response to this, Figure 5 In the winding arrangement of wires 11 to 14 shown, the first turn 13-1 of the third wire 13 is located on the core portion 3 on the side closer to the first end 4 than the first turn 11-1 of the first wire 11. Furthermore, the 20th turn 14-20 of the fourth wire 14 is embedded in the recess formed between the 19th turn 13-19 and the 20th turn 13-20 of the third wire 13. Therefore, the winding position can be stably maintained for all turns of all wires 11 to 14.

[0065] Furthermore, the first turn 12-1 of the second line 12 is shown suspended in the air, but the first turn 12-1 of the second line 12 can also be embedded between the first turn 14-1 of the fourth line 14 and the first flange portion 6. Since the first turn 14-1 of the fourth line 14 is embedded in the recess formed between the first turn 11-1 of the first line 11 and the first turn 13-1 of the third line 13, its position can be stably maintained.

[0066] Such Figure 5 The winding method shown is highly likely to be used in actual winding processes.

[0067] In addition, Figure 5 In the illustrated embodiment, the third line 13 and the fourth line 14 have turns with the same number counting from the first end 4 that are adjacent to each other, and the third line 13 is located on the portion closer to the second end 5 than the fourth line 14. This positional relationship is... Figure 2 The positions of the third line 13 and the fourth line 14 shown are opposite. However, of course, through Figure 5 The implementation shown also maintains the same Figure 2 The illustrated implementation has the same effect.

[0068] exist Figure 2 The common mode choke 1 shown and Figure 5In the common-mode choke 1a shown, the first line 11, the second line 12, the third line 13, and the fourth line 14 are all circular in cross-section and have the same outer diameter. Therefore, the winding state of each of the lines on the upper side relative to the lower side of the line, namely, the third line 13 on the upper side of the first line 11 relative to the lower side, the fourth line 14 on the upper side of the third line 13 relative to the lower side, and the second line 12 on the upper side of the fourth line relative to the lower side, can be stabilized.

[0069] In addition, Figure 2 The common mode choke 1 shown and Figure 5 The common-mode choke 1a shown does not need to have the following features: Figure 11 The location where multiple lines intersect, like the switching region C in the common-mode choke 31a shown. Therefore, with Figure 11 Compared to the common-mode choke 31a shown, the common-mode chokes 1 and 1a are easier to manufacture, and it is less difficult to produce the insulating cover layer 18 in lines 11-14 (see reference). Figure 8 Damage to lines reduces their quality.

[0070] Next, refer to Figures 6 to 8 The common-mode choke 1b in the second embodiment will be described. Figure 6 Corresponding to Figure 1 , Figure 7 Corresponding to Figure 2 .exist Figures 6 to 8 In China, for the sake of Figure 1 as well as Figure 2 The elements shown in the figure are labeled with the same reference numerals as those in the accompanying drawings, and repeated descriptions are omitted.

[0071] The common-mode choke 1b is characterized by having three wires. In short, in the common-mode choke 1b of the second embodiment, the third wire 13 performs the functions of both the third wire 13 and the fourth wire 14 in the common-mode choke 1 of the first embodiment. Therefore, according to the second embodiment, the wire winding process can be simplified compared to the first embodiment.

[0072] The common-mode choke 1b has a core 2 and three wires, namely, a first wire 11, a second wire 12, and a third wire 13. Figure 7 In order to clearly distinguish the first line 11, the second line 12, and the third line 13, the cross-sections of the first line 11 and the second line 12 are represented by hollow lines, and the cross-section of the third line 13 is shaded.

[0073] The core portion 2 is the same as the core portion 2 in the first embodiment, and has a winding core portion 3, a first flange portion 6 disposed on the side of the first end 4 in the axial direction of the winding core portion 3, and a second flange portion 7 disposed on the side of the second end 5 opposite to the side of the first end 4. The first thread 11, the second thread 12, and the third thread 13 are wound in a spiral shape in parallel from the side of the first end 4 toward the side of the second end 5 around the winding core portion 3 with substantially the same number of turns.

[0074] Similar to the core 2 in the first embodiment, a first terminal electrode 21 and a third terminal electrode 23 are provided on the first flange portion 6, and a second terminal electrode 22 and a fourth terminal electrode 24 are provided on the second flange portion 7. Figure 7 The diagrams of terminal electrodes 21 to 24 are omitted in the text.

[0075] The first end 4 of each of the first wires 11 and the second wires 12 is connected to the first terminal electrode 21, and the second end 5 of each of the first wires 11 and the second wires 12 is connected to the second terminal electrode 22. The first end 4 of the third wire 13 is connected to the third terminal electrode 23, and the second end 5 of the third wire 13 is connected to the fourth terminal electrode 24.

[0076] In the common-mode choke 1b, it can also have an equivalent to Figure 9 The top plate of the top plate 45 shown.

[0077] Main reference Figure 7 First, a first thread 11 is wound around the core portion 3 to form a first layer. Next, a third thread 13 is wound around a recess formed between adjacent turns of the first thread 11, so that a portion of its cross-section is embedded, thus forming a second layer that becomes the outer periphery of the first layer. Then, a second thread 12 is wound around a recess formed between adjacent turns of the third thread 13, so that a portion of its cross-section is embedded, thus forming a third layer that becomes the outer periphery of the second layer.

[0078] The first line 11 constituting the first layer and the third line 13 constituting the second layer are adjacent to each other when counting the turns with the same number starting from the first end 4 side of the core portion 3, and the first line 11 is located on the second end 5 side of the core portion 3 closer than the third line 13.

[0079] Furthermore, the second thread 12 and the third thread 13 constituting the third layer are adjacent to each other, counting the turns with the same number starting from the first end 4 side of the core portion 3, and the second thread 12 is located closer to the first end 4 side of the core portion 3 than the third thread 13. In addition, the first turn 12-1 of the second thread 12 is located on the first end 4 side of the first turn 11-1 of the first thread 11, and is located on the core portion 3. This winding method is similar to... Figure 5The winding method shown is the same and is highly likely to be used in actual winding processes.

[0080] In the common-mode choke 1b of the second embodiment, the stray capacitance between the first and second layers and the stray capacitance between the second and third layers are generated in opposite directions. Thus, the two types of stray capacitances with opposite directions are generated using two wires (first wire 11 and second wire 12) connected in parallel, similar to the first embodiment described above. That is, for the nth turn of one signal line, stray capacitances C1 and C2 can be generated on both the (n-1)th and (n+1)th turns of another signal line. Therefore, in the common-mode choke 1b, stray capacitance bias can be reduced not only macroscopically (i.e., the signal line as a whole) but also locally, specifically on a turn-by-turn basis. Because of this, mode-switching characteristics can be reduced even in the high-frequency range.

[0081] The common-mode choke 1b of the second embodiment includes a first inductor consisting of 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 consisting of 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 made of wires of the same specification, a difference will occur between the DC resistance of the first inductor and the DC resistance of the second inductor.

[0082] By taking appropriate measures to address the difference in DC resistance as described above, the characteristics of the common-mode choke 1b can be further improved. As a countermeasure, the following structure is preferably adopted in the second embodiment.

[0083] like Figure 8 As shown, the first wire 11, the second wire 12, and the third wire 13 each have a central conductor 17 made of a conductor such as copper with a circular cross-section, and an electrically insulating covering layer 18 covering the periphery of the central conductor 17. Here, 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 wires 11 and the second wire 12, that is, more than 1.3 times and less than 1.5 times.

[0084] By employing the structure described above, the total cross-sectional area of ​​the center conductor 17 of the first line 11 and the center conductor 17 of the second line 12 can be equal to or nearly equal to the cross-sectional area of ​​the center conductor 17 of the third line 13. As a result, the difference in DC resistance can be eliminated or nearly eliminated between the first inductor composed of the first line 11 and the second line 12 and the second inductor composed of the third line 13.

[0085] Furthermore, in the common-mode choke 1b, the first wire 11, the second wire 12, and the third wire 13 are all circular in cross-section and have the same outer diameter. This is the same as in the first embodiment, which helps to stabilize the winding state of each of the upper wires relative to the lower wires, namely, the third wire 13 above the lower wire 11 and the second wire 12 above the lower wire 13.

[0086] Additionally, in the case of common-mode choke 1b, it is also related to... Figure 2 The common mode choke 1 shown and Figure 5 The case of common-mode choke 1a shown is the same, and it does not need to have the following features. Figure 11 The location where multiple lines intersect, like the switching region C in the common-mode choke 31a shown. Therefore, with Figure 11 Compared to the case of common mode choke 31a shown, the case of common mode choke 1b is easier to manufacture and further reduces the risk of wire quality degradation such as damage to the insulation covering layer 18 in lines 11 to 13.

[0087] The above, in Figure 2 The common mode choke 1 shown and Figure 5 In the common-mode choke 1a shown, the first line 11 and the third line 13 are adjacent to each other with the same number of turns counting from the first end 4 side, and the first line 11 is located closer to the second end 5 side than the third line 13. The second line 12 and the fourth line 14 are adjacent to each other with the same number of turns counting from the first end 4 side, and the second line 12 is located closer to the first end 4 side than the fourth line 14.

[0088] In addition, Figure 7 In the common-mode choke 1b shown, the first line 11 and the third line 13 are adjacent to each other with the same number of turns counting from the first end 4 side, and the first line 11 is located closer to the second end 5 side than the third line 13. Similarly, the second line 12 and the third line 13 are adjacent to each other with the same number of turns counting from the first end 4 side, and the second line 12 is located closer to the first end 4 side than the third line 13.

[0089] That is, regardless of which of the common-mode chokes 1, 1a, and 1b is used, they all have a structure in which two regions with opposite positional relationships of two pairs of lines forming adjacent layers are stacked in a direction orthogonal to the axial direction of the core portion. Therefore, compared with the structure described in Patent Document 1, the degree of unevenness in distributed capacitance is lower, and mode switching characteristics can be reduced in a higher frequency range.

[0090] Furthermore, regardless of which of the common-mode chokes 1, 1a, and 1b is used, for two lines forming adjacent layers and paired with each other, a structure is adopted in which turns with the same number are adjacent to each other, and one line is offset by one turn from the other line. In this way, by adopting the structure of offset by one turn, the stray capacitance generated between the two lines can be limited to a minimum.

[0091] However, in this invention, for two lines forming adjacent layers and paired with each other, the structure is not limited to a structure where turns with the same number are offset by one turn; a structure with an offset of two or more turns can also be used. Furthermore, for common-mode chokes 1 and 1a, the turn offset between the first line 11 and the third line 13 can be different from the turn offset between the second line 12 and the fourth line 14. Similarly, for common-mode choke 1b, the turn offset between the first line 11 and the third line 13 can also be different from the turn offset between the second line 12 and the third line 13.

[0092] The present invention has been described above in relation to the embodiments illustrated, but various other modifications are possible within the scope of the present invention.

[0093] For example, the number of turns of a common-mode choke can be increased or decreased arbitrarily.

[0094] Furthermore, the direction of the number of turns used in the description of the implementation method may be reversed.

[0095] In addition, for the multiple wires in a common mode choke, there may be some parts that cross or twist together.

[0096] Furthermore, the illustrated embodiments are exemplary structures, and partial substitutions or combinations of structures can be made between different embodiments.

[0097] Explanation of reference numerals in the attached figures

[0098] 1, 1a, 1b… Common mode choke; 2… Core; 3… Core winding; 4… First end; 5… Second end; 6… First flange; 7… Second flange; 11… First wire; 12… Second wire; 13… Third wire; 14… Fourth wire; 17… Center wire; 18… Insulating cover layer; 21… First terminal electrode; 22… Second terminal electrode; 23… Third terminal electrode; 24… Fourth terminal electrode.

Claims

1. A common mode choke coil comprising: a core portion having a winding core portion, a first flange portion provided on a first end side of the winding core portion in an axial direction, and a second flange portion provided on a second end side of the winding core portion in the axial direction opposite to the first end side; first, second, third, and fourth wires that are parallel to each other around the winding core portion and are wound in a spiral shape, respectively; a first terminal electrode and a third terminal electrode provided on the first flange portion; and a second terminal electrode and a fourth terminal electrode provided on the second flange portion, wherein one end of each of the first and second wires is connected to the first terminal electrode, and the other end of each of the first and second wires is connected to the second terminal electrode, wherein one end of each of the third and fourth wires is connected to the third terminal electrode, and the other end of each of the third and fourth wires is connected to the fourth terminal electrode, wherein the first wire is wound around the winding core portion to form a first layer, wherein the third wire has a portion of the third wire embedded in a recess formed between adjacent turns of the first wire, and is wound on an outer peripheral side of the first layer to form a second layer, wherein the fourth wire has a portion of the fourth wire embedded in a recess formed between adjacent turns of the third wire, and is wound on an outer peripheral side of the second layer to form a third layer, wherein the second wire has a portion of the second wire embedded in a recess formed between adjacent turns of the fourth wire, and is wound on an outer peripheral side of the third layer to form a fourth layer, and wherein a bias in a local portion of stray capacitance between adjacent turns of each of the first and third wires is reduced by stray capacitance between adjacent turns of each of the second and fourth wires.

2. A common mode choke coil comprising: a core portion having a winding core portion, a first flange portion provided on a first end side of the winding core portion in an axial direction, and a second flange portion provided on a second end side of the winding core portion in the axial direction opposite to the first end side; first, second, and third wires that are parallel to each other around the winding core portion and are wound in a spiral shape, respectively; a first terminal electrode and a third terminal electrode provided on the first flange portion; and a second terminal electrode and a fourth terminal electrode provided on the second flange portion, wherein one end of each of the first and second wires is connected to the first terminal electrode, and the other end of each of the first and second wires is connected to the second terminal electrode, wherein 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, wherein the first wire is wound around the winding core portion to form a first layer, wherein the third wire has a portion of the third wire embedded in a recess formed between adjacent turns of the first wire, and is wound on an outer peripheral side of the first layer to form a second layer, wherein the second wire has a portion of the second wire embedded in a recess formed between adjacent turns of the third wire, and is wound on an outer peripheral side of the second layer to form a third layer. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ A local bias of a stray capacitance of each of the first and third lines is reduced by a different stray capacitance between turns of each of the second and third lines.

3. A common mode choke coil comprising: a core portion having a winding core portion, a first flange portion provided on a first end side in an axial direction of the winding core portion, and a second flange portion provided on a second end side in the axial direction of the winding core portion opposite to the first end side; first, second, third, and fourth lines that are parallel to each other around the winding core portion and are wound in a spiral shape, respectively; a first terminal electrode and a third terminal electrode provided on the first flange portion; and a second terminal electrode and a fourth terminal electrode provided on the second flange portion, one end of each of the first and second lines is connected to the first terminal electrode, and the other end of each of the first and second lines is connected to the second terminal electrode, one end of each of the third and fourth lines is connected to the third terminal electrode, and the other end of each of the third and fourth lines is connected to the fourth terminal electrode, the first line is wound around the winding core portion to constitute a first layer, the third line has a portion of the third line embedded in a recess formed between adjacent turns of the first line and wound on an outer circumferential side of the first layer to constitute a second layer, the fourth line has a portion of the fourth line embedded in a recess formed between adjacent turns of the third line and wound on an outer circumferential side of the second layer to constitute a third layer, the second line has a portion of the second line embedded in a recess formed between adjacent turns of the fourth line and wound on an outer circumferential side of the third layer to constitute a fourth layer, the first and third lines include a portion in which a turn of the first line counted from the first end side is offset toward the second end side by a turn of the third line counted from the first end side, the second and fourth lines include a portion in which a turn of the second line counted from the first end side is offset toward the first end side by a turn of the fourth line counted from the first end side.

4. The common mode choke coil according to claim 3, wherein an offset amount of a turn of the second line and a turn of the fourth line counted from the first end side is set in accordance with an offset amount of a turn of the first line and a turn of the third line counted from the first end side.

5. A common mode choke coil comprising: a core portion having a winding core portion, a first flange portion provided on a first end side in an axial direction of the winding core portion, and a second flange portion provided on a second end side in the axial direction of the winding core portion opposite to the first end side; first, second, and third lines that are parallel to each other around the winding core portion and are wound in a spiral shape, respectively; a first terminal electrode and a third terminal electrode provided on the first flange portion; and a second terminal electrode and a fourth terminal electrode provided on the second flange portion, one end of each of the first and second lines is connected to the first terminal electrode, and the other end of each of the first and second lines is connected to the second terminal electrode, one end of each of the third and fourth lines is connected to the third terminal electrode, and the other end of each of the third and fourth lines is connected to the fourth 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 portion to form a first layer, the third wire has a portion of the third wire embedded in a recess formed between adjacent turns of the first wire, and is wound on an outer circumferential side of the first layer to form a second layer, the second wire has a portion of the second wire embedded in a recess formed between adjacent turns of the third wire, and is wound on an outer circumferential side of the second layer to form a third layer, the first wire and the third wire include a portion in which a turn of the first wire counted from the first end side is offset toward the second end side by a turn of the third wire having the same number as the turn of the first wire, the second wire and the third wire include a portion in which a turn of the second wire counted from the first end side is offset toward the first end side by a turn of the third wire having the same number as the turn of the second wire.

6. The common mode choke coil according to claim 5, wherein an offset amount of a turn of the second wire and a turn of the third wire having the same number as the turn of the second wire is set in accordance with an offset amount of a turn of the first wire and a turn of the third wire having the same number as the turn of the first wire.

7. A common mode choke coil comprising: a core portion having a winding core portion, a first flange portion provided on a first end side in an axial direction of the winding core portion, and a second flange portion provided on a second end side in the axial direction of the winding core portion opposite to the first end side; first, second, third, and fourth wires wound in parallel around the winding core portion and wound in a spiral shape, respectively; a first terminal electrode and a third terminal electrode provided on the first flange portion; and a second terminal electrode and a fourth terminal electrode provided on the second flange portion, 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 portion to form a first layer, the third wire has a portion of the third wire embedded in a recess formed between adjacent turns of the first wire, and is wound on an outer circumferential side of the first layer to form a second layer, the fourth wire has a portion of the fourth wire embedded in a recess formed between adjacent turns of the third wire, and is wound on an outer circumferential side of the second layer to form a third layer, the second wire has a portion of the second wire embedded in a recess formed between adjacent turns of the fourth wire, and is wound on an outer circumferential side of the third layer to form a fourth layer, a certain turn of the first wire counted from the first end side and a turn of the third wire having the same number as the turn of the first wire are offset toward the second end side, a certain turn of the second wire counted from the first end side and a turn of the fourth wire having the same number as the turn of the second wire are offset toward the first end side.

8. The common mode choke coil according to claim 7, wherein for a plurality of turns of the first wire and the third wire, a turn of the first wire counted from the first end side is offset toward the second end side from a turn of the third wire having the same number as the turn of the first wire, for a plurality of turns of the second wire and the fourth wire, a turn of the second wire counted from the first end side is offset toward the first end side from a turn of the fourth wire having the same number as the turn of the second wire.

9. The common mode choke coil according to claim 8, wherein for substantially all turns of the first wire and the third wire, a turn of the first wire counted from the first end side is offset toward the second end side from a turn of the third wire having the same number as the turn of the first wire, for substantially all turns of the second wire and the fourth wire, a turn of the second wire counted from the first end side is offset toward the first end side from a turn of the fourth wire having the same number as the turn of the second wire.

10. The common mode choke coil according to any one of claims 7 to 9, wherein an offset amount of a turn of the second wire and a turn of the fourth wire having the same number as the turn of the second wire is set in accordance with an offset amount of a turn of the first wire and a turn of the third wire having the same number as the turn of the first wire.

11. A common mode choke coil comprising: a core portion having a winding core portion, a first flange portion provided on a first end side of the winding core portion in an axial direction, and a second flange portion provided on a second end side of the winding core portion in the axial direction opposite to the first end side; a first wire, a second wire, and a third wire that are parallel to each other around the winding core portion and are wound in a spiral shape, respectively; a first terminal electrode and a third terminal electrode provided on the first flange portion; and a second terminal electrode and a fourth terminal electrode provided on the second flange portion, 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 portion to constitute a first layer, the third wire has a portion of the third wire embedded in a recess formed between adjacent turns of the first wire and is wound on an outer peripheral side of the first layer to constitute a second layer, the second wire has a portion of the second wire embedded in a recess formed between adjacent turns of the third wire and is wound on an outer peripheral side of the second layer to constitute a third layer, for a plurality of turns of the first wire and the third wire, a turn of the first wire counted from the first end side is offset toward the second end side from a turn of the third wire having the same number as the turn of the first wire, for a plurality of turns of the second wire and the third wire, a turn of the second wire counted from the first end side is offset toward the first end side from a turn of the third wire having the same number as the turn of the second wire.

12. The common mode choke coil according to claim 11, wherein for a plurality of turns of the first wire and the third wire, a turn of the first wire counted from the first end side is offset toward the second end side from a turn of the third wire having the same number as the turn of the first wire, For the turns of the second wire and the third wire, a turn of the second wire counted from the first end side is offset to the first end side more than a turn of the third wire having the same number as the turn.

13. The common mode choke of claim 12, wherein, For substantially all turns of the first wire and the third wire, a turn of the first wire counted from the first end side is offset to the second end side more than a turn of the third wire having the same number as the turn. For substantially all turns of the second wire and the third wire, a turn of the second wire counted from the first end side is offset to the first end side more than a turn of the third wire having the same number as the turn.

14. The common mode choke of any one of claims 11 to 13, wherein, The offset of the turns of the second wire and the turns of the third wire having the same number as the turns of the second wire is set in accordance with the offset of the turns of the first wire and the turns of the third wire having the same number as the turns of the first wire.

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