JP2018186290A - Common mode filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve high inductance while implementing reduction of the mode conversion characteristic of a common mode filter.SOLUTION: A common mode filter 1 includes first and second wires W1 and W2 which are respectively wound around a winding core portion 11a with the same number of turns. Each of the wires W1 and W2 is wound around a first winding area AR1 at a turn number mand is also wound around a second winding area AR2 at a turn number m. The inter-line distance Dbetween the n-th turn (1≤n≤m-1) of the wire W2 and the n+1-th turn of the wire W1 in the winding area AR1 is shorter than the inter-line distance Dbetween the n-th turn of the wire W1 and the n+1-th turn of the wire W2. In addition, the inter-line distance Dbetween the n-th turn (m+1≤n≤m+ m-1) of the wire W 1 and the n+1-th turn of the wire W2 in the winding area AR2 is shorter than the inter-line distance Dbetween the n-th turn of the wire W 2 and the n+1-th turn of the wire W 1.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a common mode filter, and more particularly to a winding structure of a common mode filter.

  A common mode filter is known which includes two inductances that are provided on each of two signal lines constituting a transmission line of a differential transmission system and are magnetically coupled to each other. By inserting the common mode filter into the transmission line of the differential transmission system, it is possible to selectively remove only the common mode noise current.

  As a specific structure of the common mode filter, one using a toroidal core and one using a drum core are known. When using a toroidal core, since there is no gap inside the core and it has a high effective magnetic permeability, high noise removal performance can be obtained, but automatic winding is difficult and you have to rely on manual winding. Variation in characteristics increases. On the other hand, when a drum core is used, it is difficult to obtain a noise removal performance as high as that of a toroidal core. On the other hand, since an automatic winding method can be used, variation in characteristics can be reduced. Moreover, since the automatic winding method can be used, the drum core type common mode filter is suitable for mass production.

  Patent Documents 1 and 2 disclose examples of common mode filters configured using a drum core. In the example of Patent Document 1, two wires each constituting an inductance are wound in a two-layer structure. On the other hand, in the example of Patent Document 2, two wires each forming an inductance are wound simultaneously as a pair of wires. In general, the former winding method is called layer winding, and the latter winding method is called bifilar winding. Further, Patent Document 3 discloses an example of an automatic winding machine used for winding a wire around a drum core.

Japanese Patent No. 4789076 Japanese Patent No. 3973028 Japanese Patent No. 4737268

  By the way, in recent years, the adoption of Ethernet in in-vehicle LAN has been advanced. A common mode filter used in an in-vehicle Ethernet is required to have more stable characteristics and higher noise reduction performance than before. In this regard, the drum core type common mode filter has a feature in that variation in characteristics can be reduced as described above. Therefore, if the noise reduction performance of the drum core type common mode filter can be improved, an optimum common mode filter for an in-vehicle Ethernet can be obtained.

  What is specifically required as high noise reduction performance is a reduction in mode conversion characteristics (Scd) indicating the ratio of differential signal components input to the common mode filter that are converted into common mode noise and output. Therefore, as a result of the research conducted by the inventor of the present invention to solve this problem, the capacitance generated between different turns of a pair of wires (hereinafter referred to as “between different turns” is used to reduce the mode conversion characteristics of the common mode filter. It was found that the balance of "capacity" is greatly involved. Further, a high inductance value is also required, and for that purpose, it is a good idea to increase the number of turns of the coil.

  Accordingly, one of the objects of the present invention is to provide a drum core type common mode filter capable of realizing a high inductance while achieving a reduction in mode conversion characteristics by balancing the capacitance between different turns generated in each of a pair of coils. It is to provide.

In order to solve the above-described problems, a common mode filter according to the present invention is wound around a core part having first and second winding areas on one end side and the other end side in the longitudinal direction, respectively, and the core part. A first coil made of the first wire, and a second coil made of the second wire wound around the core portion with the same number of turns as the first wire. The first winding pattern wound around the first winding area with a first number of turns m ₁ (m ₁ is a positive number) and the second winding area with a second winding A second winding pattern wound with a number of turns m ₂ (m ₂ is a positive number), and the second wire has the first number of turns m _{1 in} the first winding area. third and winding pattern, a fourth winding wound around the second winding in turn number m ₂ in the second winding area in wound And a turn in the first winding area, the n of the second of the n ₁ turns of the wire (n ₁ is 1 or m ₁ -1 any number below) with the first wire ₁ +1 first line distance D ₁ between the turn, the second line distance D between the first n ₁ +1 turn and the n ₁ turns of the first wire and the second wire _Shorter than 2 and in the second winding area, the n ₂ turn of the first wire (n ₂ is an arbitrary number between m ₁ +1 and m ₁ + m ₂ −1) and the second wire the third line distance D ₃ of between the first n ₂ +1 turn the fourth line between the n ₂ +1 turns of the said and the n ₂ turns of the second wire first wire characterized in that less than between the distance D _4.

In the first winding area, the distributed capacity generated between the n ₁ turn of the second wire and the n ₁ +1 turn of the _first wire increases, but in the second winding area, Since the distributed capacitance generated between the n ₂ turn of the first wire and the n ₂ +1 turn of the second wire becomes large, the inter-turn capacitance can be increased with respect to both the first and second wires. It can generate uniformly, and the imbalance of the impedance of the 1st and 2nd wire can be suppressed. Therefore, the mode conversion characteristic Scd can be reduced, and a high-quality common mode filter can be realized.

  In the present invention, the first and second wires are preferably bifilar wound around the core portion. In this case, in the first winding area, the same turns of the first wire and the second wire are located on the one end side and the other end side of the core portion, respectively, In the winding area, the same turns of the first wire and the second wire are preferably located on the other end side and the one end side of the winding core part, respectively. According to this configuration, in the common mode filter that employs bifilar winding, the mode conversion characteristic Scd can be reduced, and a high-quality common mode filter can be realized.

In the present invention, the first and second wires are wound so as to overlap the first winding layer wound directly on the surface of the core portion and the first winding layer. constitute a second layer of winding layers, in the first winding area, first to m ₁ turn of the first wire, said wound directly around a surface of the core portion A first winding layer is configured, and the first to m ₁ −1 turns of the second wire are wound on the first winding layer so as to be wound on the second layer. A winding layer is formed, and the m _1st turn of the second wire is wound directly on the surface of the core portion adjacent to the m ₁ turn of the first wire, In the second winding area, the m ₁ +1 to m ₁ + m ₂ turns of the first wire are wound directly on the surface of the winding core portion, and the first winding layer is used. The m ₁ +1 turn of the second wire is wound directly on the surface of the core portion adjacent to the m ₁ +1 turn of the first wire, and the second wire of the m _{1 +.} 2 to the m _{1 +} m ₂ turns of wire, it is preferable that the wound to overlap the first layer of winding layers constituting the winding layers of said second layer. In this case, the first to m ₁ −1 turns of the second wire are wound while being fitted in the valley of the first winding layer formed by the same turn and the next turn of the first wire. The m ₁ +2 to m ₁ + m ₂ turns of the _second wire are the valleys of the first winding layer formed by the same turn and the previous turn of the first wire. It is preferable that the wire is wound while being fitted in. According to this configuration, the mode conversion characteristic Scd can be reduced in the common mode filter employing the two-layer winding, and a high quality common mode filter can be realized. Further, according to this configuration, in both the first and second winding blocks, the first winding layer is configured mainly by the first wire, and the second winding layer is mainly configured by the first winding layer. Since it comprises two wires, the winding structure is relatively simple, and the first and second wires can be easily wound.

In the present invention, the first and second wires are wound so as to overlap the first winding layer wound directly on the surface of the core portion and the first winding layer. constitute a second layer of winding layers, in the first winding area, first to m ₁ turn of the first wire, said wound directly around a surface of the core portion A first winding layer is formed, and the first turn of the second wire is wound directly on the surface of the core portion while being adjacent to the first turn of the first wire. The second to m _1st turns of the second wire are wound around the first winding layer to form the second winding layer, and the second winding In the turn area, the m ₁ +1 to m ₁ + m ₂ turns of the first wire are wound directly on the surface of the core portion to constitute the first winding layer. The m ₁ +1 to m ₁ + m ₂ −1 turns of the second wire are wound on the first winding layer to form the second winding layer. The m ₁ + m ₂ turn of the _second wire is preferably wound directly on the surface of the core portion adjacent to the m ₁ + m ₂ turn of the _first wire. In this case, the second to m ₁ turn of the second wire is wound while fitted into the valley of the first layer of the winding layers formed by the same turn and the previous turn of the first wire The m ₁ +1 to m ₁ + m ₂ −1 turns of the _second wire are valleys of the first winding layer formed by the same turn and the next turn of the first wire. It is preferable that the wire is wound while being fitted in. According to this configuration, the mode conversion characteristic Scd can be reduced in the common mode filter employing the two-layer winding, and a high quality common mode filter can be realized. Further, according to this configuration, in both the first and second winding blocks, the first winding layer is configured mainly by the first wire, and the second winding layer is mainly configured by the first winding layer. Since it comprises two wires, the winding structure is relatively simple, and the first and second wires can be easily wound.

In the present invention, the first and second wires are wound so as to overlap the first winding layer wound directly on the surface of the core portion and the first winding layer. constitute a second layer of winding layers, in the first winding area, first to m ₁ turn of the first wire, said wound directly around a surface of the core portion A first winding layer is configured, and the first to m ₁ −1 turns of the second wire are wound on the first winding layer so as to be wound on the second layer. A winding layer is formed, and the m _1st turn of the second wire is wound directly on the surface of the core portion adjacent to the m ₁ turn of the first wire, In the second winding area, the m ₁ +1 to m ₁ + m ₂ turns of the second wire are wound directly on the surface of the winding core portion, and the first winding layer is used. The m ₁ +1 to m ₁ + m ₂ −1 turns of the first wire are wound around the first winding layer to form the second winding layer. And the m ₁ + m ₂ turn of the _first wire is wound directly on the surface of the core portion adjacent to the m ₁ + m ₂ turn of the second wire. preferable. In this case, the first to m ₁ −1 turns of the second wire are wound while being fitted in the valley of the first winding layer formed by the same turn and the next turn of the first wire. The first wire winding layer formed by the same turn and the next turn of the second wire, the m ₁ +1 to the m ₁ + m ₂ −1 turn of the first wire It is preferably wound while being fitted in the valley. According to this configuration, the mode conversion characteristic Scd can be reduced in the common mode filter employing the two-layer winding, and a high quality common mode filter can be realized.

In the present invention, the first and second wires are wound so as to overlap the first winding layer wound directly on the surface of the core portion and the first winding layer. constitute a second layer of winding layers, in the first winding area, first to m ₁ turn of the first wire, said wound directly around a surface of the core portion A first winding layer is formed, and the first turn of the second wire is wound directly on the surface of the core portion while being adjacent to the first turn of the first wire. The second to m _1st turns of the second wire are wound around the first winding layer to form the second winding layer, and the second winding In the turn area, the m ₁ +1 to m ₁ + m ₂ turns of the second wire are wound directly on the surface of the core portion to form the first winding layer. Ri, the m ₁ +1 turn of the first wire, the are wound directly around the second surface of the core portion while adjacent to the first m ₁ +1 turn wire, the first wire The m ₁ +2 to m ₁ + m ₂ turns are preferably wound on the first winding layer to form the second winding layer. In this case, the second to m ₁ turn of the second wire is wound while fitted into the valley of the first layer of the winding layers formed by the same turn and the previous turn of the first wire The m ₁ +2 to m ₁ + m ₂ turns of the _second wire are fitted in the valleys of the first winding layer formed by the same turn and the previous turn of the first wire. It is preferable that the wire is wound while being wound. According to this configuration, the mode conversion characteristic Scd can be reduced in the common mode filter employing the two-layer winding, and a high quality common mode filter can be realized.

  In the present invention, it is preferable that the winding core portion further includes a space area positioned between the first winding area and the second winding area. When a space area is provided between the first winding area and the second winding area, the first and second wires can be crossed in the space area. Therefore, two winding blocks in which the positional relationship between the first and second wires is reversed can be easily realized, and the influence of the capacitance between different turns can be sufficiently reduced.

In the present invention, the difference between the first turn number m ₁ and the turn number m ₂ is preferably ¼ or less of the total number of turns of the first wire W1 or the second wire W2. In this case, it is preferable that the difference between the first turn number m ₁ and the second turn number m ₂ is 2 turns or less, and the first turn number m ₁ and the second turn number m _2. Is more preferably 1 turn or less, and it is particularly preferable that the first turn number m ₁ and the second turn number m ₂ are the same (m ₁ = m ₂ ).

  In the present invention, the first and third winding patterns constitute a first winding block, the second and fourth winding patterns constitute a second winding block, It is preferable that a plurality of unit winding structures each including a combination of the first and second winding blocks are provided on the winding core. When the number of turns of the first and second wires is very large, when they are divided finely, the balance of the capacity between different turns can be increased as compared with the case of dividing roughly. Therefore, the mode conversion characteristic Scd can be reduced, and a high-quality common mode filter can be realized.

  In the present invention, the first and third winding patterns are disposed closer to the center in the axial direction of the core portion than the first winding block and the first winding block. A third winding block having a winding structure different from that of the second winding block, and the second and fourth winding patterns include the second winding block and the second winding block. The fourth winding block is arranged closer to the center of the winding core portion in the axial direction than the second winding block and has a winding structure different from that of the second winding block. The wire block has a two-layer winding structure, the third and fourth winding blocks have a single-layer bifilar winding structure, and the first winding block and the third winding block are Divided by the first subspace, the second winding block and the front Fourth winding block is preferably is divided by the second subspace. According to this configuration, a plurality of spaces can be provided in small increments between the first winding block and the second winding block, and the boundary between the first winding area and the second winding area. Thus, when the first wire and the second wire are crossed, the moving distance from the turn before crossing to the turn after crossing can be shortened. That is, the space width between the first winding area and the second winding area can be narrowed, and immediately after the first wire and the second wire are crossed in the wire winding operation. The variation in the winding start position of the turn can be reduced.

  In the present invention, at least one adjacent turn of the third winding block is divided by a third subspace, and at least one adjacent turn of the fourth winding block is divided by a fourth subspace. It is preferable that According to this configuration, a larger number of spaces can be provided in small increments between the first winding block and the second winding block, and the first winding area and the second winding area When the first wire and the second wire are crossed at the boundary, the moving distance from the turn before crossing to the turn after crossing can be further shortened. That is, the space width between the first winding area and the second winding area can be further narrowed, and immediately after the first wire and the second wire are crossed in the wire winding operation. The variation in the winding start position of the turn can be further reduced.

  ADVANTAGE OF THE INVENTION According to this invention, the common mode filter which can obtain a high inductance can be provided, implement | achieving reduction of a mode conversion characteristic.

FIG. 1 is a schematic perspective view showing an external structure of a surface mount type common mode filter 1 according to a first embodiment of the present invention. FIG. 2 is a basic electric circuit diagram of the common mode filter 1. FIG. 3 is a more detailed equivalent circuit diagram of the common mode filter 1 shown in FIG. FIG. 4 is a schematic diagram for explaining the distributed capacity between a pair of wires. FIG. 5 is an equivalent circuit diagram showing a generation model of the distributed capacitance of the common mode filter. FIG. 6 is a cross-sectional view schematically showing the winding structure of the common mode filter 1. FIG. 7 is a cross-sectional view schematically showing the winding structure of the common mode filter 2 according to the second embodiment of the present invention. FIG. 8 is a schematic diagram for explaining a winding structure of the common mode filter 2, and (a) to (c) are diagrams showing a positional relationship between adjacent turns of a pair of wires, and (d) FIG. 4 is a diagram for explaining a capacity between different turns. FIG. 9 is a sectional view schematically showing a winding structure of the common mode filter 3 according to the third embodiment of the present invention. FIG. 10 is a schematic diagram for explaining the winding structure of the common mode filter 3, and (a) to (c) are diagrams showing the positional relationship between adjacent turns of a pair of wires, and (d) FIG. 4 is a diagram for explaining a capacity between different turns. FIG. 11 is a cross-sectional view showing the winding structure of the common mode filter 4 according to the fourth embodiment of the present invention. FIG. 12 is a schematic diagram for explaining a winding structure of the common mode filter 4, and (a) to (c) are diagrams showing a positional relationship between adjacent turns of a pair of wires, and (d) FIG. 4 is a diagram for explaining a capacity between different turns. FIG. 13 is a cross-sectional view schematically showing the winding structure of the common mode filter 5 according to the fifth embodiment of the present invention. FIG. 14 is a schematic diagram for explaining a winding structure of the common mode filter 5, and (a) to (c) are diagrams showing a positional relationship between adjacent turns of a pair of wires, and (d) FIG. 4 is a diagram for explaining a capacity between different turns. 15A and 15B are cross-sectional views schematically showing the winding structure of the common mode filter 6 according to the sixth embodiment of the present invention. FIG. 15A is a cross-sectional view showing the winding structure, and FIG. It is a figure explaining the capacity | capacitance between turns. FIG. 16 is a cross-sectional view schematically showing the winding structure of the common mode filter 7 according to the seventh embodiment of the present invention. FIG. 17 is a sectional view schematically showing the winding structure of the common mode filter 8 according to the eighth embodiment of the present invention. FIG. 18 is a cross-sectional view schematically showing the winding structure of the common mode filter 9 according to the ninth embodiment of the present invention.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a schematic perspective view showing an external structure of a surface mount type common mode filter 1 according to a first embodiment of the present invention. In the present embodiment, as shown in FIG. 1, the opposing direction of a pair of flanges 11b and 11c described later is the y direction, and the direction perpendicular to the y direction in the plane of the upper surfaces 11bs and 11cs described later is the x direction. A direction perpendicular to both the x direction and the y direction is referred to as a z direction.

  As shown in FIG. 1, the common mode filter 1 includes a drum core 11, a plate-like core 12 attached to the drum core 11, and wires W <b> 1 and W <b> 2 (first and second wires) wound around the drum core 11. It is configured with. The drum core 11 includes a rod-shaped core portion 11a having a rectangular cross section, and flanges 11b and 11c provided at both ends of the core portion 11a, and has a structure in which these are integrated. The plate-like core 12 is fixed to the lower surfaces of the flange portions 11b and 11c (surfaces opposite to the upper surfaces 11bs and 11cs). The common mode filter 1 is surface-mounted with the upper surfaces 11bs and 11cs of the flange portions 11b and 11c of the drum core 11 facing the circuit board.

  The drum core 11 and the plate-like core 12 are made of a magnetic material having a relatively high magnetic permeability, for example, a sintered body of Ni—Zn ferrite or Mn—Zn ferrite. Note that a magnetic material having a high magnetic permeability such as Mn—Zn-based ferrite usually has a low specific resistance and conductivity.

  Two terminal electrodes E1 and E2 are formed on the upper surface 11bs of the flange portion 11b, and two terminal electrodes E3 and E4 are formed on the upper surface 11cs of the flange portion 11c. The terminal electrodes E1, E2 are arranged in this order from one end side in the x direction. Similarly, the terminal electrodes E3 and E4 are also arranged in this order from one end side in the x direction. The end portions of the wires W1 and W2 are connected to the terminal electrodes E1 to E4 by thermocompression bonding.

  The wires W1 and W2 are coated conductors, and are wound around the winding core portion 11a in the same winding direction to constitute a coil conductor. The number of turns of the wires W1, W2 is also the same. In the present embodiment, the wires W1 and W2 are wound by single-layer bifilar winding. Moreover, a space is provided between adjacent turns located in the middle of the core part 11a, and thereby a space area S1 is configured. This point will be described in detail again later. The portions other than the space area S1 are wound with adjacent turns in close contact with each other. One end (end on the flange 11b side) W1a and the other end (end on the flange 11c side) W1b of the wire W1 are connected to the terminal electrodes E1 and E3, respectively. Further, one end (end on the flange 11b side) W2a and the other end (end on the flange 11c side) W2b of the wire W2 are connected to the terminal electrodes E2 and E4, respectively.

  FIG. 2 is a basic electric circuit diagram of the common mode filter 1.

  As shown in FIG. 2, the common mode filter 1 has a configuration in which an inductor 10a connected between the terminal electrodes E1 and E3 and an inductor 10b connected between the terminal electrodes E2 and E4 are magnetically coupled to each other. Have. Inductors 10a and 10b are configured by wires W1 and W2, respectively. With this configuration, when the terminal electrodes E1 and E2 are input terminals and the terminal electrodes E3 and E4 are output terminals, the differential signal input from the input terminal is hardly affected by the common mode filter 1 and is output from the output terminal. Is done. On the other hand, the common mode noise input from the input end is greatly attenuated by the common mode filter 1 and is hardly output to the output end.

  Here, the common mode filter generally has a property that a part of the differential signal input to the input end of the common mode filter is converted into common mode noise and output from the output end. Of course, this property is not desirable. Therefore, it is necessary to suppress the ratio of the differential signal converted to common mode noise (the above-described mode conversion characteristic Scd) to a certain value or less. Apart from this, the common mode filter is required to have as many turns as possible. This is to obtain the required inductance with a small size. In the common mode filter 1 according to the present embodiment, the above-mentioned problem is solved by reversing the positional relationship between the wires W1 and W2 at a substantially intermediate point in the winding direction to eliminate the uneven capacitance between different turns. This will be described in detail below.

  FIG. 3 is a more detailed equivalent circuit diagram of the common mode filter 1 shown in FIG.

As shown in FIG. 3A, the common mode filter 1 has a resistance R ₀ and a capacitance C ₀ in parallel with the inductance L in addition to the original inductance L. Further has a pair of inductance L by the wire W1, W2, the distributed capacitance C ₁ generated across between L. FIG. 3B is a diagram in which the common mode filter 1 of FIG. 3A is divided into two blocks for convenience of explanation, and the divided inductances are L / 2, respectively. Further, the parallel resistance _R 0/2, and the parallel capacitance becomes 2C _0.

  FIG. 4 is a schematic diagram for explaining the distributed capacity between a pair of wires.

As shown in FIG. 4 (a), for example, between a pair of wires of the same turn are bifilar winding distributed capacitance C ₁ has occurred, when the distance d between adjacent turns is wide distribution therebetween No capacity is generated. On the other hand, as shown in FIG. 4 (b), when the distance d between adjacent turns is small distributed capacitance (different turns capacitance) distributed across adjacent turns C ₂ is generated. That is, both distributed capacitances C ₁ and C ₂ are generated between the pair of wires.

  FIG. 5 is an equivalent circuit diagram showing a generation model of the distributed capacitance of the common mode filter.

As shown in FIG. 5 (a), when a pair of coils (inductance L) is divided into two at an intermediate position in a common mode filter composed of a pair of wires W1 and W2 wound with ordinary bifilar winding, Is a series connection of two inductances L / 2. The distributed capacitance C ₂ between adjacent turns and distributed capacitance C ₁ between the same turn is generated in the pair of coils (see FIG. 4). Here distributed capacitance C ₂ is in accordance with the division of the coil, can be divided into a distributed capacitance C ₂₂ of the distributed capacitance C ₂₁ and the other block of one block, these distributed capacitance C _21, C ₂₂ are both It is generated in parallel with the coil on the wire W2 side, whereby only the resonance point of the LC circuit by the wire W2 changes, and the mode conversion characteristic Scd also increases.

On the other hand, as shown in FIG. 5 (b), when reversed the winding order of the pair of wires W1, W2 of bifilar winding is performed at an intermediate position, the distributed capacitance C ₂₁ is wire W1 side of one of the blocks coil parallel to occur, the distributed capacitance C ₂₂ of the other blocks occurs in parallel with the wire W2 of the coil. As a result, both the resonance point of the LC circuit by the wire W1 and the resonance point of the LC circuit by the wire W2 change, but the balance of the two resonance points does not change. Therefore, Scd can be reduced. Further, since the distance d between adjacent turns can be reduced, the number of turns can be increased to increase the inductance. Be distributed capacitance C ₂ between adjacent turns by narrowing the distance d between adjacent turns is generated, because it is possible to reduce the Scd as described above.

  The above description is for the case where the two wires are bifilar wound, but the same applies to the case of layer winding. Next, the structure of the common mode filter 1 will be described in detail.

  FIG. 6 is a cross-sectional view schematically showing the winding structure of the common mode filter 1. This figure is a schematic diagram, and its shape, structure, position of each turn, etc. are slightly different from the actual ones.

  As shown in FIG. 6, the common mode filter 1 includes a pair of wires W <b> 1 and W <b> 2 wound around the core portion 11 a of the drum core 11 by bifilar winding. Bifilar winding is a winding method in which the first and second wires W1, W2 are alternately arranged one by one, and is preferably used when primary and secondary close coupling is required.

  The first wire W1 is wound in order from one end in the longitudinal direction of the core portion 11a toward the other end to form a first coil, and the second wire W2 is parallel to the first wire W1. In this state, a second coil that is wound in order from one end to the other end in the longitudinal direction of the winding core portion 11a and magnetically coupled to the first coil is configured. Since the winding directions of the first and second coils are the same, the direction of the magnetic flux generated by the current flowing through the first coil is the same as the direction of the magnetic flux generated by the current flowing through the second coil, The magnetic flux increases. With the above configuration, the first and second coils constitute a common mode filter.

  The first wire W1 and the second wire W2 have substantially the same number of turns, and preferably both are even turns. The wires W1 and W2 of this embodiment are both 6 turns. In order to increase the inductance, the number of turns should be as large as possible.

  The pair of wires W1 and W2 includes a first winding block BK1 provided in the first winding area AR1 located on one end side in the longitudinal direction of the core part 11a, and a longitudinal direction of the core part 11a. A second winding block BK2 provided in the second winding area AR2 located on the other end side is configured. A space area S1 is provided between the first winding area AR1 and the second winding area AR2, and the first winding block BK1 and the second winding block BK2 are divided by the space area S1. Has been.

The first winding block BK1 includes a first winding pattern WP1 composed of a first wire W1 wound around the first winding area AR1 with a first number of turns m ₁ = 3, Similarly, the winding area AR1 is composed of a combination with a third winding pattern WP3 made of the second wire W2 wound with the _first number of turns m ₁ = 3. The second winding block BK2 includes a second winding pattern WP2 made of the first wire W1 wound around the second winding area AR2 with the second number of turns m ₂ = 3, Similarly, the second winding area AR2 is composed of a combination with a fourth winding pattern WP4 made of the second wire W2 wound with the _second turn number m ₂ = 3. That is, the first to third turns of the first and second wires W1, W2 constitute the first winding block BK1, and the fourth to sixth turns of the first and second wires W1, W2. Constitutes a second winding block BK2.

  As shown in the figure, the same turns of the wires W1 and W2 in the first winding block BK1 are located on the left side and the right side, respectively, and are closely wound while maintaining this positional relationship. In the line block BK2, the positional relationship is reversed, and the same turns of the wires W1, W2 are positioned on the right side and the left side, respectively, and are closely wound while maintaining this positional relationship.

  That is, the position of the first wire W1 constituting the first winding block BK1 in the core axis direction of the first, second, and third turns is respectively the first, second, and second of the second wire W2. While it is on the left side of the third turn (close to one end of the core 11a), the fourth, fifth and sixth turns of the first wire W1 constituting the second winding block BK2 in the core axis direction. The positions are respectively on the right side of the fourth, fifth and sixth turns of the second wire W2 (near the other end of the core part 11a).

  In order to reverse the positional relationship between the first and second wires W1 and W2 as described above, the wires W1 and W2 are crossed on the way from the first winding area AR1 to the second winding area AR2. It is necessary to let The space area S1 is used as an area where the wires W1 and W2 are crossed. Further, when the first and second wires W1, W2 are crossed with each other in this way, the positional relationship of the end portions of the wires W1, W2 is reversed as compared with the start end portion, and the corresponding terminal electrode E3 is left as it is. , E4 (see FIG. 1) cannot be connected. In such a case, the end portions of the wires W1, W2 may be crossed again so as to be the same (parallel) as the positional relationship of the start ends of the wires W1, W2 connected to the terminal electrodes E1, E2, respectively. This also applies to other embodiments described below.

In this embodiment, the n _1st turn (n ₁ is an arbitrary number between 1 and m ₁ −1) of the second wire W2 of the first winding area AR1 and the first wire W1 of the first wire W1. n ₁ +1 first conductor spacing _{D 1} of the between the turn, between the second line distance between the first _n 1 +1 turn of the _{n 1} turns and a second wire W2 of the first wire W1 shorter than D _2. In addition, the n _2nd turn of the first wire W1 in the second winding area AR2 (n ₂ is an arbitrary number between m ₁ +1 and m ₁ + m ₂ −1) and the nth turn of the second wire W2. The third line distance D ₃ between the ₂ + 1 turn and the fourth line distance D between the n ₂ turn of the _second wire W2 and the n ₂ +1 turn of the first wire W1. Shorter than ₄ . The “distance between lines” refers to the distance (pitch) between the centers of two parallel wires. The line-to-line distances D ₁ and D ₃ are equal to the line-to-line distance in the same turn of the first and second wires W1 and W2.

For example, in the first winding area AR1, the first turn of the second wire W2 is in contact with the second turn of the first wire W1, but the first turn of the first wire W1 is the second wire. Not in contact with the second turn of W2. Therefore, the first line distance D ₁ of the between the second turn of the first turn and the first wire W1 of the second wire W2, the first turn and the second wire W2 of the first wire W1 Shorter than the second line-to-line distance D ₂ between the second turn and the second turn. Such a relationship is also established between the second and third turns of the wires W1 and W2.

On the other hand, in the second winding area AR2, the fourth turn of the first wire W1 is in contact with the fifth turn of the second wire W2, but the fourth turn of the second wire W2 is the first wire. Not in contact with W1's 5th turn. Therefore, the third line distance D ₃ of between the fourth turn and turn 5 of the second wire W2 of the first wire W1 is the fourth turn and the first wire W1 of the second wire W2 Shorter than the _fourth distance D4 between the fifth turn and the fourth turn. Such a relationship is also established between the fifth and sixth turns of the wires W1 and W2.

As described above, in the first winding area AR1, capacitive coupling between the n ₁ turn of the second wire W2 and the n ₁ +1 turn of the _first wire W1 is increased, and the distributed capacitance C ₂₁ is increased. . On the other hand, in the second winding area AR2, capacitive coupling between the n _2nd turn of the first wire W1 and the n ₂ +1 turn of the _second wire W2 is increased, and the distributed capacitance C ₂₂ is increased. That is, distributed capacitance (capacitance between different turns) generated across different turns is uniformly generated for both wires W1 and W2, so that impedance imbalance of wires W1 and W2 can be suppressed. Therefore, the mode conversion characteristic Scd can be reduced, and a high-quality common mode filter can be realized.

  FIG. 7 is a cross-sectional view schematically showing the winding structure of the common mode filter 2 according to the second embodiment of the present invention. FIG. 8 is a schematic diagram for explaining the winding structure of the common mode filter 2.

  As shown in FIG. 7, the common mode filter 2 includes a pair of wires W <b> 1 and W <b> 2 wound around the core portion 11 a of the drum core 11 by two-layer winding. The first wire W1 is wound in order from one end to the other end in the longitudinal direction of the core portion 11a to form a first coil, and the second wire W2 is also formed of the core portion 11a. A second coil that is wound in order from one end to the other end and magnetically coupled to the first coil is configured. Since the winding directions of the first and second coils are the same, the direction of the magnetic flux generated by the current flowing through the first coil is the same as the direction of the magnetic flux generated by the current flowing through the second coil, The overall magnetic flux is strengthened. With the above configuration, the first and second coils constitute a common mode filter.

  It is preferable that the first and second wires W1 and W2 have substantially the same number of turns, and both are even-numbered turns. The wires W1 and W2 of this embodiment are both 8 turns. In order to increase the inductance, the number of turns should be as large as possible.

  The pair of wires W1 and W2 includes a first winding block BK1 provided in the first winding area AR1 located on one end side in the longitudinal direction of the core part 11a, and a longitudinal direction of the core part 11a. A second winding block BK2 provided in the second winding area AR2 located on the other end side is configured. A space area S1 is provided between the first winding area AR1 and the second winding area AR2, and the first winding block BK1 and the second winding block BK2 are divided by the space area S1. Has been.

The first winding block BK1 includes a first winding pattern WP1 composed of a first wire W1 wound around the first winding area AR1 with a first number of turns m ₁ = 4, Similarly, the winding area AR1 is configured by a combination with a third winding pattern WP3 including the second wire W2 wound with the _first number of turns m ₁ = 4. In addition, the second winding block BK2 includes a second winding pattern WP2 including the first wire W1 wound around the second winding area AR2 with the second number of turns m ₂ = 4, Similarly, the second winding area AR2 is configured in combination with a fourth winding pattern WP4 including the second wire W2 wound with the second number of turns m ₂ = 4. That is, the first to fourth turns of the first and second wires W1 and W2 constitute the first winding block BK1, and the fifth to eighth turns of the first and second wires W1 and W2. Constitutes a second winding block BK2.

  In the first winding block BK1, the first to fourth turns of the first wire W1 constitute a first winding layer wound directly on the surface of the winding core portion 11a, It is wound tightly with no gap. The first to third turns of the second wire W2 constitute a second winding layer wound on the first winding layer, and in particular, between the first wires W1. It is wound while fitting in the valley. For example, the first turn of the second wire W2 is located in the valley between the first turn and the second turn of the first wire W1, and the second turn is the second turn and the third turn of the first wire W1. The third turn is located in the valley between the third turn and the fourth turn of the first wire W1. Thus, the position of each turn of the second wire W2 in the axial direction (longitudinal direction of the core portion 11a) does not coincide with the position of the same turn of the first wire W1.

  The fourth turn and the fifth turn of the second wire W2 are surplus turns that cannot be wound in the second layer, and are wound directly on the surface of the core part 11a to constitute the first winding layer. . The fourth turn of the second wire W2 is wound next to the fourth turn of the first wire W1, and forms a part of the first winding block BK1. The fifth turn of the second wire W2 is wound next to the fifth turn of the first wire W1 and forms part of the second winding block BK2.

  Ideally, the fourth turn and the fifth turn of the second wire W2 are originally formed in the second layer. However, when each turn of the second layer is arranged in the valley between adjacent turns of the first layer, one of the two turns of the first wire W1 supporting the excess turn of the second wire W2 is missing. Therefore, the position of the second layer cannot be maintained. Therefore, as a realistic structure, a state in which the fourth and fifth turns are collapsed from the beginning is adopted.

  In the second winding block BK2, the 5th to 8th turns of the first wire W1 constitute the first winding layer wound directly on the surface of the winding core part 11a. It is wound tightly with no gap. The sixth to eighth turns of the second wire W2 constitute a second winding layer wound on the first winding layer, and in particular, between the lines of the first wire W1. It is wound while fitting in the valley. For example, the sixth turn of the second wire W2 is located in the valley between the fifth and sixth turns of the first wire W1, and the seventh turn is the sixth and seventh turns of the first wire W1. The eighth turn is located in the valley between the seventh turn and the eighth turn of the first wire W1. That is, the position of each turn of the second wire W2 in the axial direction (longitudinal direction of the core portion 11a) does not coincide with the position of the same turn of the first wire W1.

  As shown in the figure, the same turns of the first and second wires W1, W2 in the first winding block BK1 are located on the left side and the right side, respectively, and are closely wound while maintaining this positional relationship. However, in the second winding block BK2, the positional relationship is reversed, and the same turns of the first and second wires W1, W2 are positioned on the right side and the left side, respectively, and dense winding is performed while maintaining this positional relationship. It has been turned.

  That is, the positions of the first wire W1 constituting the first winding block BK1 in the core axis direction of the first, second, third and fourth turns are respectively the first and second of the second wire W2. 2, 5th, 6th, 7th and 7th of the first wire W1 constituting the second winding block BK2 while being on the left side of the second, third and fourth turns (near one end of the core part 11a). The position of the eighth turn in the core axis direction is the right side of the second wire W2 on the fifth, sixth, seventh, and eighth turns (near the other end of the core 11a).

  In order to reverse the positional relationship between the first and second wires W1 and W2 as described above, the wires W1 and W2 are crossed on the way from the first winding area AR1 to the second winding area AR2. It is necessary to let The space area S1 is used as an area where the wires W1 and W2 are crossed.

In this embodiment, the n ₁ turn of the second wire W2 in the first winding area AR1 (n ₁ is an arbitrary number between 1 and m ₁ −1) and the first wire W1 The _first line distance D ₁ between the n ₁ +1 turn and the second line between the n ₁ turn of the _first wire W1 and the n ₁ +1 turn of the second wire W2 shorter than the distance _{D 2.} In addition, the n _2nd turn of the first wire W1 in the second winding area AR2 (n ₂ is an arbitrary number between m ₁ +1 and m ₁ + m ₂ −1) and the nth turn of the second wire W2. The third line distance D ₃ between the ₂ + 1 turn and the fourth line distance D between the n ₂ turn of the _second wire W2 and the n ₂ +1 turn of the first wire W1. Shorter than ₄ .

For example, as shown in FIG. 8A, in the first winding area AR1, the first turn of the second wire W2 is in contact with the second turn of the first wire W1, but the first wire W1. The first turn is not in contact with the second turn of the second wire W2. Therefore, the first line distance D ₁ of the between the second turn of the first turn and the first wire W1 of the second wire W2, the first turn and the second wire W2 of the first wire W1 Shorter than the second line-to-line distance D ₂ between the second turn and the second turn. Such a relationship is also established between the second and third turns and between the third and fourth turns of the wires W1 and W2, as shown in FIGS. 8B and 8C.

On the other hand, as shown in FIG. 8A, in the second winding area AR2, the fifth turn of the first wire W1 is in contact with the sixth turn of the second wire W2, but the second wire The fifth turn of W2 is not in contact with the sixth turn of the first wire W1. Therefore, the third line distance D ₃ of between the sixth turn of the fifth turn and the second wire W2 of the first wire W1 is the fifth turn and the first wire W1 of the second wire W2 Shorter than the _fourth distance D4 between the sixth turn and the fourth turn. Such a relationship is also established between the sixth and seventh turns and between the seventh and eighth turns of the wires W1 and W2, as shown in FIGS.

As a result, as shown in FIG. 8 (d), in the first winding area AR1, the capacitive coupling between the n ₁ turn of the second wire W2 and the n ₁ +1 turn of the _first wire W1 is strong. It becomes larger the distributed capacitance _{C 21.} On the other hand, in the second winding area AR2, capacitive coupling between the n _2nd turn of the first wire W1 and the n ₂ +1 turn of the _second wire W2 is increased, and the distributed capacitance C ₂₂ is increased. That is, distributed capacitance (capacitance between different turns) generated across different turns is uniformly generated for both wires W1 and W2, so that impedance imbalance of wires W1 and W2 can be suppressed. Therefore, the mode conversion characteristic Scd can be reduced, and a high-quality common mode filter can be realized.

  In the second embodiment, the surplus turn of the second wire to be wound on the first winding layer is the space area S1 side between the first and second winding blocks. Although it has fallen in (inner side), it may have fallen in the both ends side (outer side) of a core part.

  FIG. 9 is a sectional view schematically showing a winding structure of the common mode filter 3 according to the third embodiment of the present invention. FIG. 10 is a schematic diagram for explaining the winding structure of the common mode filter 3.

As shown in FIG. 9, the common mode filter 3 is characterized by a first winding layer in which the second wire W2 is wound directly on the surface of the winding core portion 11a. W1 is wound on the first winding layer so as to form a second winding layer, but the first wire W1 surplus that cannot be wound on the first winding layer The turn is characterized in that it falls to both ends of the core part 11a. As in the second embodiment, m ₁ = m ₂ = 4. Incidentally, the reversed the vertical position of the first and second wires W1, W2 in comparison with the second embodiment, the relationship between the final distance between lines D ₁ to D ₄ of the second embodiment This is in order to match the form, and for the convenience of explanation of the invention. The relationship between the first wire and the second wire is relative. For example, when the vertical positions of the first and second wires are the same as those in the second embodiment, the line spacing described later is used. Although the relationship between the distances D _{1 to} D ₄ is reversed, the present invention is not essentially changed.

  In the first winding block BK1, the first to fourth turns of the second wire W2 constitute the first winding layer wound directly on the surface of the winding core portion 11a, It is wound tightly with no gap. The second to fourth turns of the first wire W1 constitute a second winding layer wound on the first winding layer, and in particular, between the lines of the second wire W2. It is wound while fitting in the valley. For example, the second turn of the first wire W1 is located in the valley between the first turn and the second turn of the second wire W2, and the third turn is the second turn and the third turn of the second wire W2. The fourth turn is located in the valley between the third turn and the fourth turn of the second wire W2. That is, the position of each turn of the first wire W1 in the axial direction (longitudinal direction of the core part 11a) does not coincide with the position of the same turn of the second wire W2.

  The first turn and the eighth turn of the first wire W1 are surplus turns that cannot be wound in the second layer, and are wound directly on the surface of the core portion 11a to constitute the first winding layer. . The first turn of the first wire W1 is wound next to the first turn of the second wire W2, and forms a part of the first winding block BK1. The eighth turn of the first wire W1 is wound adjacent to and adjacent to the eighth turn of the second wire W2, and forms part of the second winding block BK2.

  Ideally, the first turn and the eighth turn of the first wire W1 are originally formed in the second layer. However, when each turn of the second layer is arranged in a valley between adjacent turns of the first layer, one of the two turns of the second wire W2 supporting the excess turn of the first wire W1 is missing. Therefore, the position of the second layer cannot be maintained. For this reason, as a realistic structure, the first and eighth turns have been collapsed from the beginning.

  In the second winding block BK2, the fifth to eighth turns of the second wire W2 constitute the first winding layer wound directly on the surface of the winding core part 11a, and the line spacing It is wound tightly with no gap. The fifth to seventh turns of the first wire W1 constitute a second winding layer wound on the first winding layer, and in particular, between the lines of the second wire W2. It is wound while fitting in the valley. Specifically, the fifth turn of the first wire W1 is located in the valley between the fifth turn and the sixth turn of the second wire W2, and the sixth turn is the sixth turn of the second wire W2. The seventh turn is located in the valley between the seventh turn and the eighth turn of the second wire W2. Thus, the position in the axial direction (longitudinal direction of the core part 11a) of each turn of the first wire W1 does not coincide with the position of the same turn of the second wire W2.

  As shown in the figure, the same turns of the first and second wires W1, W2 in the first winding block BK1 are located on the left side and the right side, respectively, and are closely wound while maintaining this positional relationship. However, in the second winding block BK2, the positional relationship is reversed, and the same turns of the first and second wires W1, W2 are positioned on the right side and the left side, respectively, and dense winding is performed while maintaining this positional relationship. It has been turned.

  That is, the positions of the first wire W1 constituting the first winding block BK1 in the core axis direction of the first, second, third and fourth turns are respectively the first and second of the second wire W2. 2, 5th, 6th, 7th and 7th of the first wire W1 constituting the second winding block BK2 while being on the left side of the second, third and fourth turns (near one end of the core part 11a). The position of the eighth turn in the core axis direction is the right side of the second wire W2 on the fifth, sixth, seventh, and eighth turns (near the other end of the core 11a).

  In order to reverse the positional relationship between the first and second wires W1 and W2 as described above, the wires W1 and W2 are crossed on the way from the first winding area AR1 to the second winding area AR2. It is necessary to let The space area S1 is used as an area where the wires W1 and W2 are crossed.

In this embodiment, the n ₁ turn of the second wire W2 in the first winding area AR1 (n ₁ is an arbitrary number between 1 and m ₁ −1) and the first wire W1 The _first line distance D ₁ between the n ₁ +1 turn and the second line between the n ₁ turn of the _first wire W1 and the n ₁ +1 turn of the second wire W2 shorter than the distance _{D 2.} In addition, the n _2nd turn of the first wire W1 in the second winding area AR2 (n ₂ is an arbitrary number between m ₁ +1 and m ₁ + m ₂ −1) and the nth turn of the second wire W2. The third line distance D ₃ between the ₂ + 1 turn and the fourth line distance D between the n ₂ turn of the _second wire W2 and the n ₂ +1 turn of the first wire W1. Shorter than ₄ .

For example, as shown in FIG. 10A, in the first winding area AR1, the first turn of the second wire W2 is in contact with the second turn of the first wire W1, but the first wire W1. The first turn is not in contact with the second turn of the second wire W2. Therefore, the first line distance D ₁ of the between the second turn of the first turn and the first wire W1 of the second wire W2, the first turn and the second wire W2 of the first wire W1 Shorter than the second line-to-line distance D ₂ between the second turn and the second turn. Such a relationship is also established between the second and third turns and between the third and fourth turns of the wires W1 and W2, as shown in FIGS.

On the other hand, as shown in FIG. 10A, in the second winding area AR2, the fifth turn of the first wire W1 is in contact with the sixth turn of the second wire W2, but the second wire The fifth turn of W2 is not in contact with the sixth turn of the second wire W2. Therefore, the third line distance D ₃ of between the sixth turn of the fifth turn and the second wire W2 of the first wire W1 is the fifth turn and the first wire W1 of the second wire W2 Shorter than the _fourth distance D4 between the sixth turn and the fourth turn. Such a relationship is also established between the sixth and seventh turns and between the seventh and eighth turns of the wires W1 and W2, as shown in FIGS.

As a result, as shown in FIG. 10 (d), in the first winding area AR1, the capacitive coupling between the n ₁ turn of the second wire W2 and the n ₁ +1 turn of the _first wire W1 is strong. It becomes larger the distributed capacitance _{C 21.} On the other hand, in the second winding area AR2, capacitive coupling between the n _2nd turn of the first wire W1 and the n ₂ +1 turn of the _second wire W2 is increased, and the distributed capacitance C ₂₂ is increased. That is, distributed capacitance (capacitance between different turns) generated across different turns is uniformly generated for both wires W1 and W2, so that impedance imbalance of wires W1 and W2 can be suppressed. Therefore, the mode conversion characteristic Scd can be reduced, and a high-quality common mode filter can be realized.

  The common mode filters 1 to 3 according to the first to third embodiments include the winding structure of the first winding block BK1 including the positional relationship of the wires W1 and W2 and the winding of the second winding block BK2. Although the wire structure is substantially symmetrical with respect to the boundary line B, as shown below, the symmetry of the winding structure including the positional relationship between the wires W1 and W2 is not required in the present invention.

  FIG. 11 is a cross-sectional view showing the winding structure of the common mode filter 4 according to the fourth embodiment of the present invention. FIG. 12 is a schematic diagram for explaining the winding structure of the common mode filter 4.

As shown in FIG. 11, the common mode filter 4 is characterized in that the first and second wires W1 and W2 are used for the first layer and the second layer of the first winding block BK1, respectively. The second and first wires W2 and W1 are used for the first layer and the second layer of the block BK2, respectively. In the second winding block BK2, the positional relationship between the wires W1 and W2 of the first winding block BK1 is increased and decreased. The point is to reverse. Further, both the first and second winding blocks BK1 and BK2 are made to fall on the surface of the core portion 11a with the final turn of the second layer wire as an extra turn. That is, a winding structure in which the first winding block BK1 of the common mode filter 2 according to the second embodiment and the second winding block BK2 of the common mode filter 3 according to the third embodiment are combined. It is characterized by having. Also in the present embodiment, m ₁ = m ₂ = 4.

  A space area S1 is provided between the first winding area AR1 and the second winding area AR2, and the first winding block BK1 and the second winding block BK2 are divided by the space area S1. Has been.

  In the first winding block BK1, the first to fourth turns of the first wire W1 constitute a first winding layer wound directly on the surface of the winding core portion 11a, It is wound tightly with no gap. The first to third turns of the second wire W2 constitute a second winding layer wound on the first winding layer, and in particular, between the first wires W1. It is wound while fitting in the valley. For example, the first turn of the second wire W2 is located in the valley between the first turn and the second turn of the first wire W1, and the second turn is the second turn and the third turn of the first wire W1. The third turn is located in the valley between the third turn and the fourth turn of the first wire W1. Thus, the position of each turn of the second wire W2 in the axial direction (longitudinal direction of the core portion 11a) does not coincide with the position of the same turn of the first wire W1.

  The fourth turn of the second wire W2 is wound directly on the surface of the core portion 11a to form the first winding layer. The fourth turn of the second wire W2 is wound next to the fourth turn of the first wire W1, and forms a part of the first winding block BK1.

  The eighth turn of the first wire W1 is wound directly around the surface of the core portion 11a to form the first winding layer. The eighth turn of the first wire W1 is wound adjacent to and adjacent to the eighth turn of the second wire W2, and forms part of the second winding block BK2.

  Ideally, the fourth turn of the second wire W2 and the eighth turn of the first wire W1 are originally formed in the second layer. However, when each turn of the second layer is arranged in the valley between adjacent turns of the first layer, one turn of the second layer becomes a surplus turn, and the surplus turn is equivalent to two turns of the first layer supporting this. Since one of them is missing, the position of the second layer cannot be maintained. Therefore, as a realistic structure, a state in which the fourth and fifth turns are collapsed from the beginning is adopted.

  In the second winding block BK2, the fifth to eighth turns of the second wire W2 constitute the first winding layer wound directly on the surface of the winding core part 11a, and the line spacing It is wound tightly with no gap. The fifth to seventh turns of the first wire W1 constitute a second winding layer wound on the first winding layer, and in particular, between the lines of the second wire W2. It is wound while fitting in the valley. For example, the fifth turn of the first wire W1 is located in the valley between the fifth and sixth turns of the second wire W2, and the sixth turn is the sixth and seventh turns of the second wire W2. The seventh turn is located in the valley between the seventh turn and the eighth turn of the second wire W2. Thus, the position in the axial direction (longitudinal direction of the core part 11a) of each turn of the first wire W1 does not coincide with the position of the same turn of the second wire W2.

  As shown in the figure, the same turns of the first and second wires W1, W2 in the first winding block BK1 are located on the left side and the right side, respectively, and are closely wound while maintaining this positional relationship. However, in the second winding block BK2, the positional relationship is reversed, and the same turns of the first and second wires W1, W2 are positioned on the right side and the left side, respectively, and dense winding is performed while maintaining this positional relationship. It has been turned.

  That is, the positions of the first wire W1 constituting the first winding block BK1 in the core axis direction of the first, second, third and fourth turns are respectively the first and second of the second wire W2. 2, 5th, 6th, 7th and 7th of the first wire W1 constituting the second winding block BK2 while being on the left side of the second, third and fourth turns (near one end of the core part 11a). The position of the eighth turn in the core axis direction is the right side of the second wire W2 on the fifth, sixth, seventh, and eighth turns (near the other end of the core 11a).

  In order to reverse the positional relationship between the first and second wires W1 and W2 as described above, the wires W1 and W2 are crossed on the way from the first winding area AR1 to the second winding area AR2. It is necessary to let The space area S1 is used as an area where the wires W1 and W2 are crossed.

In this embodiment, the n _1st turn (n ₁ is an arbitrary number between 1 and m ₁ −1) of the second wire W2 of the first winding area AR1 and the first wire W1 of the first wire W1. n ₁ +1 first conductor spacing _{D 1} of the between the turn, between the second line distance between the first _n 1 +1 turn of the _{n 1} turns and a second wire W2 of the first wire W1 shorter than D _2. In addition, the n _2nd turn of the first wire W1 in the second winding area AR2 (n ₂ is an arbitrary number between m ₁ +1 and m ₁ + m ₂ −1) and the nth turn of the second wire W2. The third line distance D ₃ between the ₂ + 1 turn and the fourth line distance D between the n ₂ turn of the _second wire W2 and the n ₂ +1 turn of the first wire W1. Shorter than ₄ .

For example, as shown in FIG. 12A, in the first winding area AR1, the first turn of the second wire W2 is in contact with the second turn of the first wire W1, but the first wire W1. The first turn is not in contact with the second turn of the second wire W2. Therefore, the first line distance D ₁ of the between the second turn of the first turn and the first wire W1 of the second wire W2, the first turn and the second wire W2 of the first wire W1 Shorter than the second line-to-line distance D ₂ between the second turn and the second turn. Such a relationship is also established between the second and third turns and between the third and fourth turns of the wires W1 and W2, as shown in FIGS.

On the other hand, as shown in FIG. 12A, in the second winding area AR2, the fifth turn of the first wire W1 is in contact with the sixth turn of the second wire W2, but the second wire The fifth turn of W2 is not in contact with the sixth turn of the first wire W1. Therefore, the third line distance D ₃ of between the sixth turn of the fifth turn and the second wire W2 of the first wire W1 is the fifth turn and the first wire W1 of the second wire W2 Shorter than the _fourth distance D4 between the sixth turn and the fourth turn. Such a relationship is also established between the sixth and seventh turns and between the seventh and eighth turns of the wires W1 and W2, as shown in FIGS.

As a result, as shown in FIG. 12 (d), in the first winding area AR1, the capacitive coupling between the n ₁ turn of the second wire W2 and the n ₁ +1 turn of the _first wire W1 is strong. It becomes larger the distributed capacitance _{C 21.} On the other hand, in the second winding area AR2, capacitive coupling between the n _2nd turn of the first wire W1 and the n ₂ +1 turn of the _second wire W2 is increased, and the distributed capacitance C ₂₂ is increased. That is, distributed capacitance (capacitance between different turns) generated across different turns is uniformly generated for both wires W1 and W2, so that impedance imbalance of wires W1 and W2 can be suppressed. Therefore, the mode conversion characteristic Scd can be reduced, and a high-quality common mode filter can be realized.

  FIG. 13 is a cross-sectional view schematically showing the winding structure of the common mode filter 5 according to the fifth embodiment of the present invention. FIG. 14 is a schematic diagram for explaining the winding structure of the common mode filter 5.

As shown in FIG. 13, the common mode filter 5 is characterized in that the second and first wires W2 and W1 are used for the first and second layers of the first winding block BK1, respectively. The first and second wires W1 and W2 are used for the first layer and the second layer of the block BK2, respectively. In the second winding block BK2, the positional relationship of the wires W1 and W2 of the first winding block BK1 is increased and decreased. The point is to reverse. Further, both the first and second winding blocks BK1 and BK2 are caused to fall on the surface of the core portion 11a with the start turn of the second layer wire as an extra turn. That is, a winding structure in which the first winding block BK1 of the common mode filter 3 according to the third embodiment and the second winding block BK2 of the common mode filter 2 according to the second embodiment are combined. It is characterized by having. Also in the present embodiment, m ₁ = m ₂ = 4.

  A space area S1 is provided between the first winding area AR1 and the second winding area AR2, and the first winding block BK1 and the second winding block BK2 are divided by the space area S1. Has been.

  In the first winding block BK1, the first to fourth turns of the second wire W2 constitute the first winding layer wound directly on the surface of the winding core portion 11a, It is wound tightly with no gap. The second to fourth turns of the first wire W1 constitute a second winding layer wound on the first winding layer, and in particular, between the first wires W1. It is wound while fitting in the valley. For example, the second turn of the first wire W1 is located in the valley between the first turn and the second turn of the second wire W2, and the third turn is the second turn and the third turn of the second wire W2. The fourth turn is located in the valley between the third turn and the fourth turn of the second wire W2. Thus, the position of each turn of the second wire W2 in the axial direction (longitudinal direction of the core portion 11a) does not coincide with the position of the same turn of the first wire W1.

  The first turn of the first wire W1 is wound directly on the surface of the core portion 11a to form the first winding layer. The first turn of the first wire W1 is wound next to the first turn of the second wire W2 constituting the first winding block BK1, and is wound around the first winding block BK1. Part.

  The fifth turn of the second wire W2 is wound directly on the surface of the winding core portion 11a to form the first winding layer. The fifth turn of the second wire W2 is wound next to the fifth turn of the first wire W1 constituting the second winding block BK2, and is wound around the second winding block BK2. Part.

  Ideally, the first turn of the first wire W1 and the fifth turn of the second wire W2 are originally formed in the second layer. However, when each turn of the second layer is arranged in the valley between adjacent turns of the first layer, one turn of the second layer becomes a surplus turn, and the surplus turn is equivalent to two turns of the first layer supporting this. Since one of them is missing, the position of the second layer cannot be maintained. Therefore, as a realistic structure, a state in which the fourth and fifth turns are collapsed from the beginning is adopted.

  In the second winding block BK2, the 5th to 8th turns of the first wire W1 constitute the first winding layer wound directly on the surface of the winding core part 11a. It is wound tightly with no gap. The sixth to eighth turns of the second wire W2 constitute a second winding layer wound on the first winding layer, and in particular, between the lines of the first wire W1. It is wound while fitting in the valley. For example, the sixth turn of the second wire W2 is located in the valley between the fifth and sixth turns of the first wire W1, and the seventh turn is the sixth and seventh turns of the first wire W1. The eighth turn is located in the valley between the seventh turn and the eighth turn of the first wire W1. Thus, the position in the axial direction (longitudinal direction of the core part 11a) of each turn of the first wire W1 does not coincide with the position of the same turn of the second wire W2.

  As shown in the figure, the same turns of the first and second wires W1, W2 in the first winding block BK1 are located on the left side and the right side, respectively, and are closely wound while maintaining this positional relationship. However, in the second winding block BK2, the positional relationship is reversed, and the same turns of the first and second wires W1, W2 are positioned on the right side and the left side, respectively, and dense winding is performed while maintaining this positional relationship. It has been turned.

  That is, the positions of the first wire W1 constituting the first winding block BK1 in the core axis direction of the first, second, third and fourth turns are respectively the first and second of the second wire W2. 2, 5th, 6th, 7th and 7th of the first wire W1 constituting the second winding block BK2 while being on the left side of the second, third and fourth turns (near one end of the core part 11a). The position of the eighth turn in the core axis direction is the right side of the second wire W2 on the fifth, sixth, seventh, and eighth turns (near the other end of the core 11a).

  In order to reverse the positional relationship between the first and second wires W1 and W2 as described above, the wires W1 and W2 are crossed on the way from the first winding area AR1 to the second winding area AR2. It is necessary to let The space area S1 is used as an area where the wires W1 and W2 are crossed.

In this embodiment, the n _1st turn (n ₁ is an arbitrary number between 1 and m ₁ −1) of the second wire W2 of the first winding area AR1 and the first wire W1 of the first wire W1. n ₁ +1 first conductor spacing _{D 1} of the between the turn, between the second line distance between the first _n 1 +1 turn of the _{n 1} turns and a second wire W2 of the first wire W1 shorter than D _2. In addition, the n _2nd turn of the first wire W1 in the second winding area AR2 (n ₂ is an arbitrary number between m ₁ +1 and m ₁ + m ₂ −1) and the nth turn of the second wire W2. The third line distance D ₃ between the ₂ + 1 turn and the fourth line distance D between the n ₂ turn of the _second wire W2 and the n ₂ +1 turn of the first wire W1. Shorter than ₄ .

For example, as shown in FIG. 14A, in the first winding area AR1, the first turn of the second wire W2 is in contact with the second turn of the first wire W1, but the first wire W1. The first turn is not in contact with the second turn of the second wire W2. Therefore, the first line distance D ₁ of the between the second turn of the first turn and the first wire W1 of the second wire W2, the first turn and the second wire W2 of the first wire W1 Shorter than the second line-to-line distance D ₂ between the second turn and the second turn. Such a relationship is also established between the second and third turns and between the third and fourth turns of the wires W1 and W2, as shown in FIGS. 14 (b) and 14 (c).

On the other hand, as shown in FIG. 14A, in the second winding area AR2, the fifth turn of the first wire W1 is in contact with the sixth turn of the second wire W2, but the second wire The fifth turn of W2 is not in contact with the sixth turn of the first wire W1. Therefore, the third line distance D ₃ of between the sixth turn of the fifth turn and the second wire W2 of the first wire W1 is the fifth turn and the first wire W1 of the second wire W2 Shorter than the _fourth distance D4 between the sixth turn and the fourth turn. Such a relationship is also established between the sixth and seventh turns and between the seventh and eighth turns of the wires W1 and W2, as shown in FIGS.

As a result, as shown in FIG. 14 (d), in the first winding area AR1, the capacitive coupling between the n ₁ turn of the second wire W2 and the n ₁ +1 turn of the _first wire W1 is strong. It becomes larger the distributed capacitance _{C 21.} On the other hand, in the second winding area AR2, capacitive coupling between the n _2nd turn of the first wire W1 and the n ₂ +1 turn of the _second wire W2 is increased, and the distributed capacitance C ₂₂ is increased. That is, distributed capacitance (capacitance between different turns) generated across different turns is uniformly generated for both wires W1 and W2, so that impedance imbalance of wires W1 and W2 can be suppressed. Therefore, the mode conversion characteristic Scd can be reduced, and a high-quality common mode filter can be realized.

  FIG. 15 is a cross-sectional view schematically showing the winding structure of the common mode filter 6 according to the sixth embodiment of the present invention.

A common mode filter 6 shown in FIG. 15 is a modification of the common mode filter 2 according to the second embodiment, and the number of turns of the first and second wires W1 and W2 is an odd number of turns (here, 9 turns). It is characterized by being. Therefore, the first winding block BK1 includes a first winding pattern composed of the first wire W1 wound around the first winding area AR1 with the first number of turns m ₁ = 4, Similarly, the winding area AR1 is composed of a combination with a third winding pattern composed of the second wire W2 wound with the _first number of turns m ₁ = 4. Further, the second winding block BK2 includes a second winding pattern composed of the first wire W1 wound around the second winding area AR2 with the second number of turns m ₂ = 5, and a second winding pattern BK2. Similarly, the winding area AR2 is composed of a combination with a fourth winding pattern composed of the second wire W2 wound with the second number of turns m ₂ = 5.

  In the present embodiment, since the second winding block BK2 has one more turn, the balance of the inter-turn capacitance is slightly worse than that in the first embodiment. However, compared with the conventional winding structure that does not balance at all, the balance of the capacity between different turns can be greatly improved, and the effect is remarkable. In particular, as the number of turns of the wires W1 and W2 increases, the effect of balancing the capacitance between different turns increases, so the effect of one turn difference is diluted and can be almost ignored.

The difference between the number of turns _{m 2} of the first winding block the first and second wires in BK1 W1, W2 number of turns _{m 1} and the first and second in the second winding block BK2 wires W1, W2 | M ₁ −m ₂ | is preferably ¼ or less of the total number of turns of the first wire W1 (or the second wire W2). For example, when the total number of turns (m ₁ + m ₂ ) of the first and second wires W1 and W2 is 10 turns, the difference in number of turns (| m ₁ −m ₂ |) is 2.5 turns or less. (Strictly speaking, it is preferably 2 turns or less). When the difference in the number of turns exceeds 1/4 of the total number of turns of the wire, the effect cannot be ignored and the noise reduction effect is insufficient, but both are less than 1/4. This is because the impedance imbalance of the windings is relatively small, and there is no practical problem.

Further, the difference in number of turns (| m ₁ −m ₂ |) is more preferably 2 turns or less regardless of the total number of turns of the first wire W1 (or the second wire W2). The turn or less is particularly preferable. If you do not intend to provide a difference in the number of turns, in most cases the difference in the number of turns can be kept within 2 turns, usually within 1 turn. This is because the imbalance effect is very small and is almost the same as when there is no difference in the number of turns.

  In addition, although this embodiment is a modification when the number of turns of the first and second wires W1, W2 of the common mode filter 2 according to the second embodiment is an odd number of turns, In the common mode filters 3 to 5 according to the embodiment, the number of turns of the first and second wires W1 and W2 may be odd.

  FIG. 16 is a cross-sectional view schematically showing the winding structure of the common mode filter 7 according to the seventh embodiment of the present invention.

  As shown in FIG. 16, the common mode filter 7 is characterized by a third winding block BK3 disposed closer to the center in the longitudinal direction of the winding core than the first winding block BK1, and the second winding block BK1. And a fourth winding block BK4 disposed closer to the longitudinal center of the winding core than the wire block BK2, and the third and fourth winding blocks BK3 and BK4 have a single-layer bifilar winding structure. The first winding block BK1 and the third winding block BK3 are divided by the first subspace, and the second winding block BK2 and the fourth winding block BK4 are the second subspace. It is in the point divided by. Details will be described below.

  The common mode filter 7 according to the present embodiment includes a pair of wires W1 and W2 wound around the core portion 11a of the drum core 11 as in the above-described embodiments. The first wire W1 is wound in order from one end to the other end in the longitudinal direction of the core portion 11a to form a first coil, and the second wire W2 is also formed of the core portion 11a. A second coil that is wound in order from one end to the other end and magnetically coupled to the first coil is configured. Since the winding directions of the first and second coils are the same, the direction of the magnetic flux generated by the current flowing through the first coil is the same as the direction of the magnetic flux generated by the current flowing through the second coil, The overall magnetic flux is strengthened. With the above configuration, the first and second coils constitute a common mode filter.

  It is preferable that the first and second wires W1 and W2 have substantially the same number of turns, and both are even-numbered turns. The wires W1 and W2 of this embodiment are both 12 turns. In order to increase the inductance, the number of turns should be as large as possible.

  The pair of wires W1 and W2 includes the first winding block BK1 provided in the first winding area AR1 located on one end side in the longitudinal direction of the winding core portion 11a, and the first winding area AR1. A third winding block BK3 provided in the second winding block BK2 provided in the second winding area AR2 located on the other end side in the longitudinal direction of the winding core portion 11a, A fourth winding block BK4 is provided in the second winding area AR2.

  In the present embodiment, the number of turns of the first and second wires W1 and W2 constituting the first and second winding blocks BK1 and BK2, respectively, is four, and the third and fourth winding blocks The number of turns of the first and second wires W1 and W2 constituting BK3 and BK4, respectively, is two.

  The first winding block BK1 is located on one end side in the longitudinal direction of the winding core portion 11a with respect to the third winding block BK3, and the third winding block BK3 has a winding core with respect to the first winding block BK1. It is located on the center side of the part 11a. Similarly, the second winding block BK2 is located on the other end side in the longitudinal direction of the core 11a with respect to the fourth winding block BK4, and the fourth winding block BK4 is the second winding block BK2. It is located in the center side of the core part 11a rather than. The first winding block BK1, the third winding block BK3, the fourth winding block BK4, and the second winding block BK2 are provided in this order from one end of the winding core portion 11a to the other end. It has been.

  A space area S1 is provided between the first winding area AR1 and the second winding area AR2, and third and second windings adjacent to each other between the first and second winding areas AR1 and AR2. The four winding blocks BK3 and BK4 are divided by the space area S1. Further, in the first winding area AR1, a first subspace SS1 is provided between the first winding block BK1 and the third winding block BK3, and both of the first winding block BK1 and the third winding block BK3 are the first subspace SS1. It is divided by the space SS1. Similarly, in the second winding area AR2, a second subspace SS2 is provided between the second winding block BK2 and the fourth winding block BK4. It is divided by subspace SS2.

The first winding block BK1 has a winding pattern composed of the first wire W1 wound in the first winding area AR1 with the number of turns m ₁₁ = 4, and the first winding block BK1 is also turned in the first winding area AR1. It is composed of a combination of a winding pattern of a second wire W2 wound by the number m _{11 = 4.}

  The first to fourth turns of the first wire W1 constituting the first winding block BK1 constitute a first winding layer wound directly on the surface of the winding core part 11a, It is tightly wound with no gap in between. The first to third turns of the second wire W2 constitute a second winding layer wound on the first winding layer, and in particular, between the first wires W1. It is wound while fitting in the valley. The fourth turn of the second wire W2 is an extra turn that cannot be wound in the second layer, and is wound directly on the surface of the core portion 11a to constitute the first winding layer. The fourth turn of the second wire W2 is wound next to the fourth turn of the first wire W1, and forms a part of the first winding block BK1.

The second winding block BK2 has the same winding pattern of the first wire W1 wound in the second winding area AR2 with the number of turns m ₂₁ = 4 and the second winding area AR2. It is composed of a combination of a winding pattern of a second wire W2 wound by the number m _{21 = 4.}

  The ninth to twelfth turns of the first wire W1 constituting the second winding block BK2 constitute the first winding layer wound directly on the surface of the winding core portion 11a, It is tightly wound with no gap in between. The tenth to twelfth turns of the second wire W2 constitute a second winding layer wound on the first winding layer, and in particular, between the first wires W1. It is wound while fitting in the valley. The ninth turn of the second wire W2 is a surplus turn that cannot be wound in the second layer, and is wound directly on the surface of the core portion 11a to constitute the first winding layer. The ninth turn of the second wire W2 is wound next to the ninth turn of the first wire W1, and forms a part of the second winding block BK2.

  Ideally, the fourth and ninth turns of the second wire W2 are originally formed in the second layer. However, when each turn of the second layer is arranged in the valley of the adjacent turn of the first layer, one of the two turns of the first wire W1 supporting the surplus turn of the second wire W2 is missing. Therefore, the position of the second layer cannot be maintained. For this reason, as a realistic structure, the fourth and ninth turns are adopted from the beginning.

  The winding structure of the first and second winding blocks BK1 and BK2 according to the present embodiment is the two-layer winding structure shown in FIG. 7, but the other winding structure shown in FIG. 9, FIG. 11, or FIG. It is also possible to adopt a two-layer winding structure.

  Next, the third and fourth winding blocks BK3 and BK4 will be described.

  In the present embodiment, the first and second winding blocks BK1 and BK2 are made of two-layer winding, whereas the third and fourth winding blocks BK3 and BK4 are made of single-layer bifilar winding. The first winding block BK1 and the third winding block BK3 are divided by the first subspace SS1, and the second winding block and the fourth winding block BK4 are also divided by the second subspace SS2. Is divided by.

The third winding block BK3 includes a winding pattern composed of the first wire W1 wound with the number of turns m ₁₂ = 2 in the first winding area AR1, and the same turn in the first winding area AR1. It constituted in combination with a winding pattern of a second wire W2 wound by the number m _{12 = 2.} The fifth and sixth turns of the first and second wires W1, W2 constituting the third winding block BK3 constitute a single-layer bifilar winding wound directly on the surface of the core part 11a. It is tightly wound with no gap between the wires.

Fourth winding block BK4, the second winding and the first wire W1 wound in turns number _{m 22} = 2 in the area AR2, a second winding also number of turns in the area AR2 _m 22 = 2 It is comprised by the combination with the 2nd wire W2 wound by. The seventh and eighth turns of the first and second wires W1, W2 constituting the fourth winding block BK4 constitute a single-layer bifilar winding wound directly on the surface of the core portion 11a. It is tightly wound with no gap between the wires.

Therefore, as shown in the figure, the first wire W1 constitutes the first winding pattern WP1 having the first turn number m ₁ (m ₁ = m ₁₁ + m ₁₂ ) in the first winding area AR1. In the second winding area AR2, a second winding pattern WP2 having a _second turn number m ₂ (m ₂ = m ₂₁ + m ₂₂ ) is configured. Similarly, the second wire W2 forms the third winding pattern WP3 having the _first number of turns m1 in the first winding area AR1, and the second winding W2 in the second winding area AR2. A fourth winding pattern WP4 having the number of turns m ₂ is formed.

  Also in the present embodiment, the same turns of the first and second wires W1 and W2 in the first and third winding blocks BK1 and BK3 are located on the left side and the right side, respectively, and the close relationship is maintained while maintaining this positional relationship. It is wound around. In the fourth and second winding blocks BK4, BK2, this positional relationship is reversed, and the same turns of the first and second wires W1, W2 are positioned on the right side and the left side, respectively, while maintaining this relationship. It is tightly wound.

  That is, the positions of the first wire W1 constituting the first winding block BK1 in the core axis direction of the first, second, third and fourth turns are respectively the first and second of the second wire W2. 2, the left side of the third and fourth turns (near one end of the core part 11a). The positions in the core axis direction of the fifth and sixth turns of the first wire W1 are also on the left side of the fifth and sixth turns of the second wire W2, respectively.

  On the other hand, the positions of the ninth, tenth, eleventh and twelfth turns in the core axis direction of the first wire W1 constituting the second winding block BK2 are the ninth of the second wire W2. The right side of the tenth, eleventh and twelfth turns (near the other end of the core 11a). The positions in the core axis direction of the seventh and eighth turns of the first wire W1 are also on the right side of the seventh and eighth turns of the second wire W2, respectively.

  In order to reverse the positional relationship between the first and second wires W1 and W2 as described above, the wires W1 and W2 are crossed on the way from the first winding area AR1 to the second winding area AR2. It is necessary to let The space area S1 is used as an area where the wires W1 and W2 are crossed.

Further, in the present embodiment, the n ₁ turn of the second wire W2 in the first winding area AR1 (n ₁ is an arbitrary number between 1 and m ₁ −1) and the first wire W1 The _first line distance D ₁ between the n ₁ +1 turn and the second line between the n ₁ turn of the _first wire W1 and the n ₁ +1 turn of the second wire W2 shorter than the distance _{D 2.} This relationship is established not only in the first winding block BK1, but also in the third winding block BK3 and the boundary between both blocks. In addition, the n _2nd turn of the first wire W1 in the second winding area AR2 (n ₂ is an arbitrary number between m ₁ +1 and m ₁ + m ₂ −1) and the nth turn of the second wire W2. The third line distance D ₃ between the ₂ + 1 turn and the fourth line distance D between the n ₂ turn of the _second wire W2 and the n ₂ +1 turn of the first wire W1. Shorter than ₄ . This relationship is established not only in the second winding block BK2, but also in the fourth winding block BK4 and the boundary between both blocks.

Thus, also in the present embodiment, in the first winding area AR1, capacitive coupling between the n ₁ turn of the second wire W2 and the n _{1 + 1} turn of the _first wire W1 becomes strong, and the distributed capacitance In contrast to the increase in C ₂₁ , in the second winding area AR2, capacitive coupling between the n ₂ turn of the first wire W1 and the n ₂ +1 turn of the _second wire W2 is increased, and the distributed capacitance is increased. C ₂₂ is increased. In other words, the distributed capacitance (capacitance between different turns) generated across different turns is generated uniformly for both wires W1 and W2, so that the impedance imbalance of the wires W1 and W2 can be suppressed. Therefore, the mode conversion characteristic Scd can be reduced, and a high-quality common mode filter can be realized.

  Further, in the present embodiment, when the wires W1 and W2 are crossed to switch from the first winding block BK1 to the second winding block BK2, the two-layer winding is once converted into a single-layer winding and the two layers Since a subspace is provided between the layer winding and the single layer winding, and thereby a plurality of spaces are provided in small increments between the first winding block BK1 and the second winding block BK2, When the wires W1 and W2 are crossed at the boundary between the second winding areas AR1 and AR2, the moving distance from the turn before crossing to the turn after crossing can be shortened. That is, the width of the space area S1 between the first winding area AR1 and the second winding area AR2 can be reduced, and the wires W1 and W2 immediately after the wires W1 and W2 are crossed during the wire winding operation. The variation in the winding start position of the turn can be reduced. This not only facilitates the wire winding operation, but also reduces variations in the characteristics of the common mode filter.

  FIG. 17 is a sectional view schematically showing the winding structure of the common mode filter 8 according to the eighth embodiment of the present invention.

  As shown in FIG. 17, the common mode filter 8 is characterized in that a third subspace SS3 is provided between adjacent turns of the third winding block BK3 of the common mode filter 7 of FIG. The fourth subspace SS4 is provided between adjacent turns of the BK4. In the present embodiment, there is only one boundary position between adjacent turns in the winding blocks BK3, BK4, so there is only one third and fourth subspace SS3, SS4. When the number of turns of the fourth winding block BK3, BK4 is large, the third and fourth subspaces SS3, SS4 may be provided at each of the boundary positions of a plurality of adjacent turns.

  As described above, in the present embodiment, a subspace is provided between adjacent turns of the single-layer winding, whereby a larger number of spaces are provided between the first winding block BK1 and the second winding block BK2. Therefore, when the wires W1 and W2 are crossed at the boundary between the first and second winding areas AR1 and AR2, the moving distance from the turn before crossing to the turn after crossing can be further shortened. . That is, the width of the space area S1 between the first winding area AR1 and the second winding area AR2 can be reduced, and the wires W1 and W2 immediately after the wires W1 and W2 are crossed during the wire winding operation. The variation in the winding start position of the turn can be further reduced. This not only facilitates the wire winding operation, but also reduces variations in the characteristics of the common mode filter.

  FIG. 18 is a cross-sectional view schematically showing the winding structure of the common mode filter 9 according to the ninth embodiment of the present invention.

  As shown in FIG. 18, the common mode filter 9 is an application example of the common mode filter 2 according to the second embodiment. The common mode filter 9 is a combination of the first and second winding blocks BK1 and BK2 shown in the drawing. A unit winding structure U is provided, and a plurality (two in this case) of the unit winding structures U are provided on the winding core portion 11a. In the present embodiment, two unit winding structures U1 and U2 are provided, and the winding structure formed by the first and second wires W1 and W2 is divided into four winding blocks. When the number of turns of the first and second wires W1 and W2 is very large (for example, 80 turns), when they are finely divided (for example, 20 turns × 4), when they are divided roughly (for example, 40 turns × 2) ) Can increase the balance of capacity between different turns. Therefore, the mode conversion characteristic Scd can be reduced, and a high-quality common mode filter can be realized.

  This embodiment is an application example of the common mode filter 2 according to the second embodiment, but as an application example of the common mode filters 1, 3 to 8 according to the first, third to eighth embodiments. Further, a combination of these may be used.

  The present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention, and it goes without saying that these are also included in the present invention. Yes.

  For example, in the above-described embodiment, a drum core is used as a core around which a pair of wires are wound. However, the core in the present invention is not limited to the drum core, as long as it has a core portion for the pair of wires. Any shape of core may be used. The cross-sectional shape of the core part is not necessarily rectangular, and may be hexagonal, octagonal, circular, elliptical, or the like. Further, the number of turns of each wire may be larger than that in the above embodiment. For example, the layer winding may be 30 to 50 turns and the inductance may be about 200 to 400 μH, or the bifilar winding may be 15 to 25 turns and the inductance may be 100 to 200 μH.

  In the above embodiment, the first and second wires W1, W2 are crossed in the space area S1, but the point where the wires W1, W2 cross is not limited to the space area S1, for example, The wires W1 and W2 moved from the space area S1 to the second winding area AR2 may be crossed immediately before being wound around the core 11a. Furthermore, if the wires W1 and W2 can be crossed, the space area S1 can be omitted.

In the above embodiment, the first turn number m ₁ of the first and second wires W1, W2 in the first winding area is a positive integer (4 turns, 6 turns, etc.), and similarly said second turn number m ₂ of the second first in winding area and second wires W1, W2 although a positive integer, not necessarily positive integer, what if a positive number It may be a turn. Therefore, for example, a halfway number of turns such as 4.5 turns may be used.

1 to 9 Common mode filters 10a and 10b Inductor 11 Drum core 11a Winding core portions 11b and 11c Top surface 12 of flange portion 11bs and 11cs Plate core AR1 First winding area AR2 Second winding area B Boundary line BK1 1st winding block BK2 2nd winding block BK3 3rd winding block BK4 4th winding block C ₀ capacitance C ₁ , C ₂ distributed capacitance C ₂₁ , C ₂₂ distributed capacitance (capacity between different turns)
D ₁ to D _4-wire distance E1~E4 terminal electrodes L inductance _{R 0} resistance S1 space area SS1~SS4 subspace Scd mode conversion characteristics U, U1, U2 unit winding structure W1 first wire W2 second wire WP1 First winding pattern WP2 Second winding pattern WP3 Third winding pattern WP4 Fourth winding pattern m ₁ Number of turns of first and second wires in the first winding area m _11th The number of turns of the first and second wires in one winding block m ₁₂ The number of turns of the first and second wires in the third winding block m ₂ The first and second turns in the second winding area Number of turns of second wire m ₂₁ Number of turns of first and second wires in second winding block m ₂₂ Number of turns of first and second wires in fourth winding block

Claims (2)

A winding core,
Comprising first and second wires wound around the core,
The first and second wires cross on the core portion,
The same turn of the first wire and the second wire is wound adjacent to each other,
The length of the first section in which the first wire is located in the lower layer and the second wire is located in the upper layer is such that the second wire is located in the lower layer and the first wire is located in the upper layer. A common mode filter characterized by being equal to the length of the second section. A first flange provided on one side in the axial direction of the core;
A second collar provided on the other side of the core in the axial direction;
First and second terminal electrodes provided on the first flange and connected to one ends of the first and second wires, respectively;
A third terminal electrode and a fourth terminal electrode provided on the second flange and connected to the other ends of the first and second wires, respectively;
In the same turn of the first and second wires, a third section in which the first wire is located on the first collar side and the second wire is located on the second collar side The length of the second wire is equal to the length of the fourth section in which the second wire is located on the first collar side and the first wire is located on the second collar side. The common mode filter according to claim 1.

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