JP2006050576A - Filter element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a filter element which reduces variations of noise damping characteristics even if there are considerable variations in output impedance of a noise source. <P>SOLUTION: The filter element comprises: a coil portion 5 constructed by overlapping and winding a signaling electrical belt-like conductor and a grounding electrical belt-like conductor via belt-like insulators; an input terminal 2 connected to a terminal side positioned on an outer circumferential of the coil portion 5 in the signaling electrical belt-like conductor and drawn out from the outer circumferential of the coil portion 5; and an output terminal 3 connected within a 1/3 area of the total length of the signaling belt-like conductor around a central point in the signaling belt-like conductor along with the direction of its length. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a filter element formed by winding a strip-shaped conductor on a strip-shaped insulator.

  As this type of filter element, a filter element disclosed in Japanese Patent No. 2826320 is known.

  A filter element (hereinafter, also referred to as “filter”) disclosed as a comparative example in the above publication includes a cylindrical winding portion and three leads (terminals) provided on one end surface thereof. Has been. In this case, the winding part is formed by winding a laminated body in which a strip-shaped conductor and a grounding strip-shaped conductor are overlapped via two dielectric layers, around the rotating winding shaft a plurality of times. The first inner lead for input / output is connected in the vicinity of the inner end of the strip-shaped conductor. The first outer lead for input / output is connected to the vicinity of the outer side of the strip-shaped conductor. Further, the grounding outer lead is connected to the vicinity of the outer end of the grounding strip-like conductor, shifted from the first outer lead by 1/2 turn around the winding axis.

With this configuration, in this filter, the three leads (terminals) can be surely arranged in a straight line (in-line). For this reason, according to this filter, attachment to the board | substrate of a filter becomes easy, and it can fully endure the physical stress added from the outside. In addition, since the interval between the leads can be always constant, it is possible to reduce variations in attenuation characteristics with respect to noise.
Japanese Patent No. 2826320 (page 3-4, Fig. 1-2)

  However, this type of filter has the following problems. In other words, this type of filter has a problem that the attenuation characteristic with respect to noise varies greatly when used in a circuit (for example, a secondary output circuit of a switching power supply device) having a large variation in output impedance.

  The present invention has been made to solve the above-described problems, and has as its main object to provide a filter element with little variation in attenuation characteristics with respect to noise even when the output impedance of the noise source varies greatly. To do.

  In order to achieve the above object, the filter element according to claim 1 is formed in a cylindrical shape as a whole by winding a signal strip conductor and a ground strip conductor in a state of being overlapped via a strip insulator. A coil portion, an input terminal connected to an end portion located on the outer peripheral side of the coil portion in the signal strip conductor, and drawn from an outer peripheral portion of the coil portion, and in the signal strip conductor And an output terminal connected to a region of one third of the total length of the signal strip conductor centered on the center point along the length direction. Here, the “strip-shaped conductor” in the present invention is not limited to a sheet-shaped conductor having a small thickness, but a conductor having a certain thickness, for example, a cross-sectional shape formed in a round shape, an ellipse shape, a square shape, or a trapezoid shape. It is meant to include a flexible plate-like conductor. Moreover, the edge part side of a strip | belt-shaped conductor means the site | part within one turn from the edge in the strip | belt-shaped conductor.

  According to a second aspect of the present invention, in the filter element according to the first aspect, the coil portion is formed by winding the signal strip conductor so that the ground strip conductor is outside. ing.

  According to a third aspect of the present invention, in the filter element according to the first or second aspect, the output terminal is connected to a portion of the coil portion that is located on the opposite side of the drawing portion of the input terminal across the center of the coil portion. Has been pulled out.

  According to a fourth aspect of the present invention, in the filter element according to any one of the first to third aspects, the filter element is connected to an end portion located on the outer peripheral side of the coil portion in the grounding strip conductor. A grounding terminal led out from an outer peripheral side portion of the coil portion located on the opposite side to the lead-out portion of the input terminal across the center of the coil portion is provided.

  The filter element according to claim 5 includes a coil portion formed in a tubular shape as a whole by winding a signal strip conductor and a ground strip conductor in a state of being overlapped with each other via a strip insulator. An input terminal connected to an end portion located on the inner peripheral side of the coil portion in the signal strip conductor and drawn out from an inner peripheral portion of the coil portion, and its length in the signal strip conductor And an output terminal connected in a region of one third of the entire length of the signal strip conductor around the center point along the vertical direction.

  The filter element according to claim 6 is the filter element according to claim 5, wherein the coil portion is formed by winding the signal strip-shaped conductor around the ground strip-shaped conductor. Has been.

  The filter element according to claim 7 is the filter element according to claim 5 or 6, wherein the output terminal is connected to a part of the coil portion that is located on the opposite side of the input terminal from the center of the coil part. Has been pulled out.

  Moreover, the filter element of Claim 8 is connected to the edge part side located in the inner peripheral side of the said coil part in the said strip | belt-shaped conductor for grounding in the filter element in any one of Claim 5 to 7. In addition, a grounding terminal led out from the inner peripheral side portion of the coil portion located on the opposite side to the lead-out portion of the input terminal across the center of the coil portion is provided.

  The filter element according to claim 9 is the filter element according to any one of claims 1 to 8, wherein the output terminal has the signal strip shape when the number of turns of the signal strip conductor is n. It is connected to the portion of the n / 2th winding in the conductor.

  The filter element according to claim 10 is the filter element according to any one of claims 1 to 8, wherein the output terminal is connected to the center point of the signal strip-shaped conductor.

  The filter element according to claim 11 is formed into a tubular shape as a whole by winding a plurality of signal strip conductors arranged in parallel and a ground strip conductor in a state of being overlapped via a strip insulator. A plurality of input terminals each connected to each end portion located on the outer peripheral side of the coil portion in each of the signal strip conductors and led out from the outer peripheral side portion of the coil portion; A plurality of output terminals respectively connected to a region of one third of the total length of the signal strip conductors around the central point along the length direction of the signal strip conductors. I have.

  A filter element according to a twelfth aspect is the filter element according to the eleventh aspect, wherein the coil section is wound around the signal strip conductors so that the ground strip conductor is outside. Is formed.

  Further, the filter element according to claim 13 is the filter element according to claim 11 or 12, wherein each of the outputs from a portion located on the opposite side of the drawing portion of each input terminal across the center of the coil portion. Each terminal is pulled out.

  Further, the filter element according to claim 14 is connected to an end portion located on an outer peripheral side of the coil portion in the grounding strip-shaped conductor in the filter element according to any one of claims 11 to 13. A grounding terminal led out from the outer peripheral portion of the coil portion located on the opposite side of the lead portion of each input terminal across the center of the coil portion is provided.

  Further, the filter element according to claim 15 is formed into a tubular shape as a whole by winding a plurality of signal strip conductors arranged in parallel and a strip strip conductor for grounding with a strip insulator interposed therebetween. A plurality of input terminals connected to the formed coil portion and each end side located on the inner peripheral side of the coil portion in each of the signal strip conductors and led out from the inner peripheral portion of the coil portion And a plurality of output terminals respectively connected in a region of one third of the total length of each signal strip conductor around the respective center points along the length direction of each signal strip conductor And.

  The filter element according to claim 16 is the filter element according to claim 15, wherein the coil band is wound around the ground strip conductor so that the signal strip conductors are outside. Is formed.

  Further, the filter element according to claim 17 is the filter element according to claim 15 or 16, wherein each of the outputs from a portion located on the opposite side of the drawing portion of each input terminal across the center of the coil portion. Each terminal is pulled out.

  Moreover, the filter element of Claim 18 is connected to the edge part located in the inner peripheral side of the said coil part in the said strip | belt-shaped conductor for grounding in the filter element in any one of Claim 15 to 17. In addition, a grounding terminal led out from the inner peripheral side portion of the coil portion located on the opposite side to the lead-out portion of each input terminal across the center of the coil portion is provided.

  The filter element according to claim 19 is the filter element according to any one of claims 11 to 18, wherein each output terminal is connected to each of the signal strip conductors when the number of turns of the signal strip conductor is n. Each of the signal strip conductors is connected to a portion of the n / 2th winding.

  The filter element according to claim 20 is the filter element according to any one of claims 11 to 18, wherein each of the output terminals is connected to the center point of each of the signal strip conductors.

  The filter element according to claim 21 includes a coil portion formed in a cylindrical shape as a whole by winding a signal strip conductor and a ground strip conductor in a state of being overlapped via a strip insulator. An input portion is defined on the end side of the signal strip-shaped conductor located on the outer peripheral side of the coil portion, and the signal is centered on a central point along the length direction of the signal strip-shaped conductor. An output region is defined in an area of one third of the entire length of the strip-shaped conductor.

  The filter element according to claim 22 is the filter element according to claim 21, wherein the coil portion is wound around the signal strip conductor so that the ground strip conductor is outside. Is formed.

  The filter element according to claim 23 is the filter element according to claim 21 or 22, wherein the output part is defined as a part located on the opposite side of the input part across the center of the coil part. Yes.

  The filter element according to claim 24 is the filter element according to any one of claims 21 to 23, wherein the filter element is located on an end side located on an outer peripheral side of the coil part in the grounding strip-shaped conductor, and the coil A grounding part is defined at a part located opposite to the input part with the center of the part interposed therebetween.

  According to a 25th aspect of the present invention, there is provided a filter element comprising a coil portion formed in a tubular shape as a whole by winding a signal strip conductor and a ground strip conductor in a state of being overlapped via a strip insulator. The input portion is defined on the end portion located on the inner peripheral side of the coil portion in the signal strip conductor, and the signal is centered on the central point along the length direction of the signal strip conductor. An output region is defined in an area of one third of the entire length of the strip-shaped conductor.

  The filter element according to claim 26 is the filter element according to claim 25, wherein the coil portion is wound around the ground strip conductor so that the signal strip conductor is on the outside. Has been.

  The filter element according to claim 27 is the filter element according to claim 25 or 26, wherein the output part is defined as a part located on the opposite side of the input part across the center of the coil part. Yes.

  A filter element according to claim 28 is the filter element according to any one of claims 25 to 27, wherein the filter element is located on an end portion side located on an inner peripheral side of the coil portion in the ground strip-shaped conductor, A grounding part is defined in a part located on the opposite side of the input part across the center of the coil part.

  The filter element according to claim 29 is the filter element according to any one of claims 21 to 28, wherein the output region is the signal band-shaped conductive material when the number of turns of the signal belt-shaped conductor is n. It is defined at the site of approximately n / 2 turns in the body.

  A filter element according to a thirty-third aspect is the filter element according to any one of the twenty-first to twenty-eighth aspects, wherein the output portion is defined at the center point of the signal strip conductor.

  The filter element according to claim 31 is formed in a cylindrical shape as a whole by winding a plurality of signal strip conductors arranged in parallel and a ground strip conductor in a state of being overlapped via a strip insulator. A plurality of input portions are defined on each end side located on the outer peripheral side of the coil portion in each signal strip conductor, and the length direction in each signal strip conductor A plurality of output parts are respectively defined in a region of one third of the total length of each of the signal strip conductors centered on the center point along.

  A filter element according to a thirty-second aspect is the filter element according to the thirty-first aspect, wherein the coil portion is wound around the signal strip conductors so that the ground strip conductor is outside. Is formed.

  A filter element according to a thirty-third aspect is the filter element according to the thirty-first or thirty-second aspect, wherein each of the output parts is located at a part located on the opposite side of the input part across the center of the coil part. Defined filter element.

  A filter element according to a thirty-fourth aspect is the filter element according to any one of the thirty-first to thirty-third aspects, wherein the filter element is located on an end side located on an outer peripheral side of the coil part in the grounding strip-shaped conductor, A grounding part is defined at a part located on the opposite side of the input part across the center of the part.

  The filter element of claim 35 is formed in a cylindrical shape as a whole by winding a plurality of signal strip conductors arranged in parallel and a ground strip conductor in a state of being overlapped with each other via a strip insulator. A plurality of input portions are defined on each end side located on the inner peripheral side of the coil portion in each signal strip conductor, and the length direction in each signal strip conductor A filter element in which a plurality of output parts are defined in a region of one third of the total length of each signal strip conductor centered on each center point along the line.

  The filter element according to claim 36 is the filter element according to claim 35, wherein the coil portion is wound around the ground strip conductor so that the signal strip conductors are outside. Is formed.

  A filter element according to a thirty-seventh aspect is the filter element according to the thirty-fifth or thirty-sixth aspect, wherein each output part is defined as a part located on the opposite side of each input part across the center of the coil portion. Has been.

  The filter element according to claim 38 is the filter element according to any one of claims 35 to 37, wherein the filter element is located on an end side located on an inner peripheral side of the coil part in the ground strip-shaped conductor, A grounding part is defined in a part located on the opposite side to the input part with the center of the coil portion interposed therebetween.

  The filter element according to claim 39 is the filter element according to any one of claims 31 to 38, wherein each output portion is connected to each signal when the number of turns of each signal strip conductor is n. Each band conductor is defined at approximately n / 2 turns.

  The filter element according to claim 40 is the filter element according to any of claims 31 to 38, wherein each output portion is defined at the center point of each of the signal strip conductors.

  The filter element according to claim 41 is the filter element according to any one of claims 1 to 40, wherein a magnetic body is disposed in a gap formed in a central portion of the coil portion.

  According to the filter element of Claim 1 and 21, the coil formed in the cylindrical shape as a whole by winding in the state which accumulated the strip | belt-shaped conductor for signals, and the strip | belt-shaped conductor for grounding via the strip | belt-shaped insulator. A center point along the length direction of the signal strip conductor, defining an input portion for connecting the input terminal to the end portion located on the outer peripheral side of the coil portion of the signal strip conductor By defining the output part for connecting the output terminal in the region of one-third of the total length of the signal strip conductor centering on the center, the grounding is connected to the inner peripheral side of the output terminal (output part) The signal strip conductor can be disposed in a state where the strip insulator is interposed between the strip conductor and the strip conductor. For this reason, a capacitor having a portion on the inner peripheral side of the output portion in the signal strip conductor as one electrode and a portion in the ground strip conductor facing the inner peripheral portion as the other electrode, It can be formed between the output terminal (output part) and ground. Therefore, according to the filter element, normal mode noise can be bypassed from the output terminal (output part) to the ground side via this capacitor. As a result, even if the filter element is used for an output filter of a noise source with a large fluctuation in output impedance. Therefore, it is possible to realize a normal mode filter element with little variation in attenuation characteristics with respect to noise.

  In this case, in order to obtain excellent noise attenuation characteristics, the coil portion is preferably formed by winding the grounding strip-shaped conductor around the signal strip-shaped conductor. In addition, the output terminal (output part) is preferably located on the opposite side of the input terminal (input part) across the center of the coil part, and the outer periphery of the coil part in the strip-shaped conductor for grounding The grounding part for connecting the grounding terminal to the part located on the side opposite to the input terminal (input part) across the center of the coil part is defined. preferable.

  The filter element according to claim 5 and 25 is formed in a cylindrical shape as a whole by winding the signal strip conductor and the ground strip conductor in a state of being overlapped via the strip insulator. An input portion for connecting the input terminal to the end portion located on the inner peripheral side of the coil portion in the signal strip conductor, and along the length direction of the signal strip conductor By defining the output part for connecting the output terminal in the region of one third of the total length of the signal strip conductor centered on the center point, the outer peripheral side than the output terminal (output part), The signal strip conductor can be disposed in a state where the strip insulator is interposed between the ground strip conductor. For this reason, a capacitor having one electrode at the outer peripheral side of the output band of the signal strip conductor and the other electrode at the ground strip conductor facing the outer peripheral section is connected to the output terminal. It can be formed between the (output part) and the ground. Therefore, according to the filter element, normal mode noise can be bypassed from the output terminal (output part) to the ground side via this capacitor. As a result, even if the filter element is used for an output filter of a noise source with a large fluctuation in output impedance. Therefore, it is possible to realize a normal mode filter element with little variation in attenuation characteristics with respect to noise.

  In this case, in order to provide excellent noise attenuation characteristics, the coil portion is preferably formed by winding the signal strip conductor to the outside with respect to the ground strip conductor. The output terminal (output part) is preferably located on the opposite side of the input terminal (input part) across the center of the coil part. The grounding part for connecting the grounding terminal to the part located on the side opposite to the input terminal (input part) across the center of the coil part is defined on the end side located on the circumferential side Is preferred.

  According to the filter element of claims 9 and 29, when the number of turns of the signal strip conductor is n, the portion of the signal strip conductor approximately n / 2 is defined as the output portion. As a result, it is possible to achieve a good balance between ensuring the number of turns for the strip conductor for signal and ensuring the capacity for the above-mentioned capacitor, resulting in a filter element for normal mode with less variation in attenuation characteristics against noise can do. In addition, when the coil portion is manufactured, the output terminal can be connected to the signal strip conductor by using the number of turns of the signal strip conductor as a guide, so that the output terminal can be reliably connected to a desired position.

  According to the filter element of claims 10 and 30, since the output portion for connecting the output terminal to the center point of the signal strip conductor is defined, the number of turns for the signal strip conductor can be secured. As a result, it is possible to realize a normal mode filter element with less variation in attenuation characteristics with respect to noise.

  In addition, according to the filter element of the eleventh and thirty-first aspects, the plurality of signal strip conductors arranged in parallel and the ground strip conductor are wound in a state of being overlapped via the strip insulator. Each of the signal strip-shaped conductors is defined as an input portion for connecting an input terminal to each end portion located on the outer peripheral side of the coil portion in each signal strip-shaped conductor. By defining the output part for connecting the output terminal in the region of one-third of the total length of each signal strip conductor centering on the central point along the length direction in the conductor, Each signal strip conductor can be disposed on the inner peripheral side of the output terminal (each output portion) with a strip insulator interposed between the output terminal and each ground portion. For this reason, each part on the inner peripheral side from each output part in each signal strip conductor is set as one electrode, and each part in the ground strip conductor facing each part on the inner peripheral side is the other part. A plurality of capacitors serving as electrodes can be formed between each output terminal (each output part) and ground. Therefore, according to this filter element, the common mode noise can be bypassed from each output terminal (each output part) to the ground side via these capacitors. As a result, the output filter of the noise source having a large output impedance variation can be obtained. Even if it is used, it is possible to realize a common-mode filter element with little variation in attenuation characteristics with respect to noise.

  In this case, in order to improve the noise attenuation characteristics, the coil portion is formed by winding each signal strip conductor so that the ground strip conductor is outside. Preferably, each output terminal (each output part) is preferably located on the side opposite to the input terminal (input part) across the center of the coil portion, and further, the coil in the strip-shaped conductor for grounding The grounding part for connecting the grounding terminal to the part located on the opposite side of each input terminal (each input part) across the center of the coil part is defined on the end side located on the outer peripheral side of the part It is preferable.

  According to the filter element of claims 15 and 35, the plurality of signal strip conductors arranged in parallel and the ground strip conductor are wound in a state of being overlapped via the strip insulator. Each of the signal strip-shaped conductors is provided with an input portion for connecting an input terminal to each end portion located on the inner peripheral side of the coil portion, and for each signal By defining an output part for connecting the output terminal in a region of one third of the total length of each signal strip conductor centered on each center point along the length direction in the strip conductor Each signal strip conductor can be disposed on the outer peripheral side of each output terminal (each output portion) with a strip insulator interposed between the output terminal (each output portion) and the ground strip conductor. For this reason, each part on the outer periphery side of each output part in each signal strip conductor is one electrode, and each part in the ground strip conductor facing each part on the outer periphery side is the other electrode. A plurality of capacitors can be formed between each output terminal (each output part) and ground. Therefore, according to this filter element, the common mode noise can be bypassed from each output terminal (each output part) to the ground side via these capacitors. As a result, the output filter of the noise source having a large output impedance variation can be obtained. Even if it is used, it is possible to realize a common-mode filter element with little variation in attenuation characteristics with respect to noise.

  In this case, in order to improve the noise attenuation characteristics, the coil portion is formed by winding each signal strip conductor to the outside with respect to the ground strip conductor. Preferably, each output terminal (each output part) is located on the opposite side of each input terminal (each input part) across the center of the coil portion, and further, a grounding strip conductor A grounding part for connecting a grounding terminal to a part located on the inner side of the coil part and located on the opposite side of each input terminal (each input part) across the center of the coil part Is preferably defined.

  In addition, according to the filter elements of claims 19 and 39, when the number of turns of each signal strip conductor is n, an approximately n / 2 turn portion of each signal strip conductor is defined as the output portion. As a result, it is possible to achieve a good balance between securing the number of turns for each signal strip conductor and securing the capacitance of the above-mentioned capacitor. As a result, the common mode filter has less variation in attenuation characteristics with respect to noise. An element can be realized. Further, when the coil portion is manufactured, each output terminal can be connected to each signal strip conductor based on the number of turns of each signal strip conductor, so that the output terminal is securely connected to a desired position. be able to.

  Further, according to the filter elements of claims 20 and 40, the output number for connecting each output terminal to the center point of each signal strip conductor is defined, so that the number of turns of the signal strip conductor is determined. As a result, the common mode filter element with less variation in attenuation characteristics with respect to noise can be realized.

  According to the filter element of claim 41, since the inductance of the signal strip conductor can be increased by arranging the magnetic body in the gap formed in the central portion of the coil portion, noise attenuation is achieved. A filter element with better characteristics can be realized.

  Hereinafter, the best mode of a filter element according to the present invention will be described with reference to the accompanying drawings.

  First, the filter element 1 according to the present invention will be described with reference to the drawings.

  As shown in FIG. 1, the filter element 1 includes an input terminal 2, an output terminal 3, a ground terminal 4, a coil portion 5, and a columnar (as an example, a columnar) magnetic core 6, and is a distributed constant type. 3 terminal type noise filter (low-pass normal mode filter).

  As shown in FIG. 3, the coil portion 5 is substantially the same as the strip-shaped insulators 5a and 5b, the ground strip-shaped conductor 7 formed narrower than the strip-shaped insulators 5a and 5b, and the ground strip-shaped conductor 7. A signal strip conductor 8 having the same planar shape is provided. In this case, each of the strip insulators 5a and 5b is configured to have the same width, the same length, and a uniform thickness by using a dielectric and electrical insulating material (polyimide, polyethylene, insulating paper, etc.). ing. The belt-like conductor for grounding (hereinafter also referred to as “grounding conductor”) 7 is formed to have a uniform thickness, and the grounding terminal 4 is electrically connected to one end side (left end side in FIG. 3). Yes. Specifically, the grounding terminal 4 is connected to a grounding portion defined in one turn (outermost peripheral portion, region Y in FIG. 3) at the end of winding in the grounding conductor 7. The grounding conductor 7 is overlaid on the strip-like insulator 5a so as to be positioned at the center in the width direction of the strip-like insulator 5a. The strip insulator 5b is overlaid on the strip insulator 5a so as to sandwich the grounding conductor 7 between the strip insulator 5a.

  The signal strip-shaped conductor (hereinafter also referred to as “signal conductor”) 8 is formed to have a uniform thickness, and the input terminal 2 is electrically connected to one end side (the left end side in FIG. 3). Yes. Specifically, the input terminal 2 is connected to an input portion defined within one turn (outermost peripheral portion, region Y in FIG. 3) at the end of winding in the signal conductor 8. In this case, the input part is defined at a position shifted by one-half turn along the length direction of the conductors 7 and 8 with respect to the connection position (grounding part) of the grounding terminal 4. An output part is defined on the center point W along the length direction of the signal conductor 8, and the output terminal 3 is electrically connected to the output part. In this case, the connection position (output part) of the output terminal 3 is not limited to the center point W, but is a region around the center point W in the signal conductor 8 (three minutes of the total length of the signal conductor 8). The region of length 1) can be defined at any position within X. Therefore, for example, when the number of turns of the signal conductor 8 is n turns, an approximately n / 2 turn (turn) portion of the signal conductor 8 is defined as an output portion, and the output terminal 3 is connected to this portion. Can also be connected. By doing so, the output terminal 3 can be connected to the signal conductor 8 with reference to the number of turns (number of turns) of the signal conductor 8 when the coil portion 5 is manufactured. It can be reliably connected to a desired position. Further, the signal conductor 8 is overlaid on the strip insulator 5b so as to be positioned at the center of the strip insulator 5b in the width direction. That is, the conductors 7 and 8 are overlaid on the strip insulator 5a with the strip insulator 5b sandwiched therebetween. The coil portion 5 starts winding the strip insulators 5a and 5b and the conductors 7 and 8 stacked on each other in this manner on the other end side (right end portion side in FIG. 3) of the conductors 7 and 8. As shown in FIG. 1 as a whole, the grounding conductor 7 is wound around the signal conductor 8 so that the grounding conductor 7 is on the outside, thereby forming a cylindrical shape with a gap H formed in the center. ). The magnetic core 6 is mounted in the gap H and disposed at the center of the coil portion 5.

  In this coil part 5, one end side of the signal conductor 8 to which the input terminal 2 is connected is located on the outer peripheral side of the coil part 5, and the input terminal 2 is one of the coil parts 5 as shown in FIG. It is pulled out from the outer peripheral side site | part (drawer site | part A in FIG. 2) in the end surface (upper end surface in FIG. 1). The output terminal 3 is on a virtual plane L (hereinafter also referred to as “plane L”) including the center (center axis O) of the coil portion 5 and the lead-out portion A of the input terminal 2, and the center axis O ( Alternatively, it is drawn out from a drawing portion B located on the opposite side of the drawing portion A across the gap H or the magnetic core 6). Further, one end side of the grounding conductor 7 to which the grounding terminal 4 is connected is located on the outer peripheral side of the coil part 5, and the grounding terminal 4 is one end face of the coil part 5 as shown in FIG. 1. It is pulled out from the outer peripheral side part (drawing part C in FIG. 2). Specifically, the lead portion C of the ground terminal 4 is on the plane L as shown in FIG. 2 and is opposite to the lead portion A across the central axis O (in other words, the lead portion B is It is defined on the opposite side of the drawing portion A). Here, the “drawing part” of the input terminal 2 or the like in the present invention refers to a part on the surface of the coil part 5 from which the input terminal 2 or the like protrudes (draws) from the coil part 5. In this case, the input terminal 2, the output terminal 3, and the grounding terminal 4 are linearly drawn to one end face side of the coil portion 5 along the width direction of the signal conductor 8. For this reason, as shown in FIG. 2, in the state which looked at the coil part 5 from one end surface, the input site | part prescribed | regulated to the extraction | drawer site | part A of the input terminal 2, and the one end side (outermost peripheral part) of the signal conductor 8 Is almost the same. Similarly, the lead-out part B of the output terminal 3 substantially coincides with the output part defined in the signal conductor 8, and the lead-out part C of the ground terminal 4 is substantially the same as the ground part defined in the grounding conductor 7. Match. Note that the definition of the extraction part and the positional relationship between each extraction part and the input part are also applied to the filter elements 11, 21, 31 described later. Therefore, the input portion and the output portion defined in the signal conductor 8 and the ground portion defined in the ground conductor 7 are also in the same plane with the same positional relationship as each of the lead portions A, B, and C described above. It is specified above.

  According to the filter element 1, the grounding conductor 7 is outside the signal conductor 8 in a state where the signal conductor 8 and the grounding conductor 7 are overlapped via the strip insulators 5 a and 5 b. The input terminal 2 is provided at an input portion defined on the end side (outermost peripheral portion) located on the outer peripheral side of the coil portion 5 in the signal conductor 8. Connected and pulled out from the outer peripheral part of the coil part 5, connected to the output part 3 defined in the region X on the center side of the signal conductor 8, and input with the central axis O of the coil part 5 interposed therebetween Pulled out from the lead-out part B located on the opposite side of the lead-out part A of the terminal 2 and grounded to the grounding part defined on the end side (outermost part) located on the outer peripheral side of the coil part 5 in the grounding conductor 7 Connect the terminal 4 and insert the central axis O of the coil part 5 The lead portion B of the output terminal 3 in the coil portion 5 (the output portion in the signal conductor 8) is pulled out from the lead portion C on the outer peripheral side of the coil portion 5 located on the opposite side to the lead portion A of the terminal 2. Further, the signal conductor 8 can be disposed on the inner peripheral side in a state where the band-like insulator 5b is interposed between the conductor 7 and the grounding conductor 7. For this reason, a part of the signal conductor 8 on the inner peripheral side of the output part 3 of the output terminal 3 is used as one electrode, and a part of the grounding conductor 7 facing the inner peripheral part is used as the other electrode. Can be formed between the output terminal 3 (the output part of the signal conductor 8) and the ground. Therefore, according to this filter element 1, normal mode noise can be bypassed from the output terminal 3 (the output portion of the signal conductor 8) to the ground side via this capacitor, and as a result, noise with large fluctuations in output impedance can be obtained. Even when the filter is used as a source output filter, it is possible to realize a normal mode filter element with little variation in attenuation characteristics with respect to noise. Further, according to the filter element 1, the center point W of the signal conductor 8 is defined as an output part, and the output terminal 3 is connected to the output part, thereby ensuring the number of turns for the signal conductor 8. As a result, it is possible to realize a normal mode filter element with less variation in attenuation characteristics with respect to noise. Moreover, since the inductance of the signal conductor 8 can be increased by the magnetic core 6, a filter element with better noise attenuation characteristics can be realized.

  Next, FIG. 13 specifically shows how the attenuation characteristics with respect to noise of the filter element 1 change when the output impedance is changed to 5Ω, 50Ω, and 500Ω using a network analyzer (R3767CG manufactured by ADVANTEST). Show. Further, FIG. 14 shows a change in attenuation characteristics with respect to noise for the filter element 51 as a comparative example measured in the same manner. In this case, the filter element 51 as a comparative example is arranged so that the grounding conductor is outside the signal conductor in a state where the signal conductor and the grounding conductor are overlapped with each other via the strip insulator. The coil portion 55 is formed by winding, and as shown in FIG. 16, the input terminal 2 is connected to the input portion defined on the end portion side (outermost peripheral portion) located on the outer peripheral side of the coil portion 55 in the signal conductor. At the same time, it is pulled out from the outer peripheral side portion of the coil portion 55 and defined on the end portion side of the signal conductor located on the inner peripheral side of the coil portion 55 (one turn (the innermost peripheral portion) at the beginning of winding in the signal conductor). The output terminal 3 is connected to the output portion and the central axis O of the coil portion 55 is sandwiched between the output portion 3 and pulled out from the lead portion located on the opposite side to the lead portion of the input terminal 2, and the outer peripheral side of the coil portion 55 in the grounding conductor End side located at (outermost circumference The grounding terminal 4 is connected to the grounding part specified in (1), and the lead-out part of the output terminal 3 is sandwiched between the lead-out part of the input terminal 2 and the lead-out part of the coil part 55 located on the side opposite to the lead-out part Has been. Further, in the filter element 1, the number of turns of the signal conductor 8 sandwiched between the input terminal 2 and the output terminal 3 is defined as 7 turns. On the other hand, also in the filter element 51 as a comparative example, the number of turns of the signal conductor sandwiched between the input terminal 2 and the output terminal 3 is defined as 7 turns.

  13 and 14, when the output impedance of the network analyzer is changed to 5Ω, 50Ω, and 500Ω, the variation in attenuation amount for each frequency (variation in attenuation characteristics) for the filter element 1 is the filter element 51. It can be confirmed that it is clearly less than the variation in attenuation for each frequency.

  Next, the configuration of the filter element 11 according to the present invention will be described with reference to FIGS. In addition, about the structure same as the filter element 1, the same code | symbol is attached | subjected and the overlapping description is abbreviate | omitted.

  As shown in FIG. 4, the filter element 11 includes an input terminal 2, an output terminal 3, a ground terminal 4, a coil unit 15, and a magnetic core 6, and is a distributed constant type three-terminal noise filter (low It functions as a band-pass normal mode filter).

  As shown in FIG. 6, the coil portion 15 includes strip-shaped insulators 5 a and 5 b, a ground strip-shaped conductor 7, and a signal strip-shaped conductor 8. In this case, the input terminal 2 is electrically connected to the other end side (right end side in FIG. 6) of the signal conductor 8. Specifically, the input terminal 2 is connected to an input portion defined within one turn (innermost peripheral portion, region Y in FIG. 6) at the beginning of winding in the signal conductor 8. The output terminal 3 is electrically connected to an output part (specifically, on the center point W) defined in the region X of the signal conductor 8. In this case, the connection position (output part) of the output terminal 3 is not limited to the center point W in the same manner as the filter element 1, and is within the region X centered on the center point W in the signal conductor 8. It can be defined at any position. The signal conductor 8 is overlaid on the strip insulator 5a so as to be positioned at the center of the strip insulator 5a in the width direction. The strip insulator 5b is overlaid on the strip insulator 5a so that the signal conductor 8 is sandwiched between the strip insulator 5a. The grounding terminal 4 is electrically connected to the other end side (right end side in FIG. 6) of the grounding conductor 7. Specifically, the grounding terminal 4 is connected to a grounding site defined within one turn (innermost peripheral portion, region Y in FIG. 6) of the grounding conductor 7 at the start of winding. In this case, the connection position (grounding part) of the grounding terminal 4 is shifted from the connection position (input part) of the input terminal 2 by a half turn along the length direction of the respective conductors 7 and 8. It is prescribed. The grounding conductor 7 is overlaid on the strip-like insulator 5b so as to be positioned at the center of the strip-like insulator 5b in the width direction. That is, the conductors 7 and 8 are overlaid on the strip insulator 5a with the strip insulator 5b sandwiched therebetween. The coil portion 15 starts winding the strip insulators 5a and 5b and the conductors 7 and 8 stacked on each other in this manner on the other end side (the right end portion side in FIG. 6) of the conductors 7 and 8. As shown in FIG. 4 as a whole, the signal conductor 8 is wound around the grounding conductor 7 so as to be on the outer side, thereby forming a cylindrical shape (cylindrical shape with a gap H formed at the center). ). The magnetic core 6 is mounted in the gap H and disposed at the center of the coil portion 15.

  In this coil part 15, the other end side of the signal conductor 8 to which the input terminal 2 is connected is located on the inner peripheral side of the coil part 15, and the input terminal 2 is connected to the coil part 15 as shown in FIG. Is pulled out from an inner peripheral side portion (drawer portion A in FIG. 5) on one end face (upper end surface in FIG. 4). Further, the other end side of the grounding conductor 7 to which the grounding terminal 4 is connected is located on the inner peripheral side of the coil portion 15, and the grounding terminal 4 is one of the coil portions 15 as shown in FIG. 4. It is pulled out from the inner peripheral side part (drawing part C in FIG. 5) in the end face of the. Here, the lead portion C of the ground terminal 4 is on a plane L including the central axis O of the coil portion 15 and the lead portion A of the input terminal 2 as shown in FIG. The gap H or the magnetic core 6) is defined on the side opposite to the lead-out portion A of the input terminal 2. The output terminal 3 is on a plane L including the central axis O of the coil portion 15 and the lead-out portion A of the input terminal 2, and the output terminal 3 sandwiches the center (center axis O) of the coil portion 15. The lead is pulled out from a lead portion B located on the opposite side to the lead portion A (in other words, on the side opposite to the lead portion A of the input terminal 2 across the lead portion C of the ground terminal 4).

  According to this filter element 11, the signal conductor 8 is outside the ground conductor 7 in a state where the signal conductor 8 and the ground conductor 7 are overlapped via the strip insulators 5a and 5b. The input terminal is provided at an input portion defined on the end side (innermost peripheral portion) located on the inner peripheral side of the coil portion 15 in the signal conductor 8. 2 is connected and pulled out from the inner peripheral side portion of the coil portion 15 and grounded to the grounding portion defined on the end side (innermost peripheral portion) located on the inner peripheral side of the coil portion 15 in the grounding conductor 7. The signal conductor is connected by connecting the terminal 4 and pulling out from the inner peripheral side portion (leading portion) C of the coil portion 15 located on the opposite side of the drawing portion A of the input terminal 2 across the central axis O of the coil portion 15. The output terminal 3 is connected to the output portion defined in the region X on the center side of 8. By connecting and pulling out from the lead-out part B located on the opposite side of the lead-out part A of the input terminal 2 across the central axis O of the coil part 15, the lead-out part B of the output terminal 3 in the coil part 15 (for signal) The signal conductor 8 can be disposed on the outer peripheral side of the output portion of the conductor 8 with the band-like insulator 5b interposed between the conductor 8 and the grounding conductor 7. For this reason, the part on the outer peripheral side of the output terminal 3 of the output conductor 3 in the signal conductor 8 is used as one electrode, and the part in the grounding conductor 7 facing the outer peripheral part is used as the other electrode. A capacitor can be formed between the output terminal 3 (the output part of the signal conductor 8) and the ground. Therefore, according to the filter element 11, normal mode noise can be bypassed from the output terminal 3 (the output portion of the signal conductor 8) to the ground side via this capacitor, and as a result, noise with large fluctuations in output impedance can be obtained. Even when the filter is used as a source output filter, it is possible to realize a normal mode filter element with little variation in attenuation characteristics with respect to noise. Further, according to the filter element 11, the center point W of the signal conductor 8 is defined as an output part, and the output terminal 3 is connected to the output part, thereby ensuring the number of turns for the signal conductor 8. As a result, it is possible to realize a normal mode filter element with less variation in attenuation characteristics with respect to noise.

  Next, the filter element 21 according to the present invention will be described with reference to the drawings.

  First, the configuration of the filter element 21 will be described. The filter element 21 is configured as a common mode filter by changing the configuration of the signal conductor 8 of the filter element 1 that functions as a normal mode filter. For this reason, most of the components are common to the corresponding components of the filter element 1. Therefore, the same components as those of the filter element 1 are denoted by the same reference numerals, and redundant description is omitted.

  As shown in FIG. 7, the filter element 21 includes a pair of input terminals 2a and 2b (hereinafter also referred to as “input terminal 2” when not distinguished), and a pair of output terminals 3a and 3b (hereinafter referred to as “output terminals” when not distinguished from each other). 3 ”), a pair of grounding terminals 4a and 4b (hereinafter also referred to as“ grounding terminal 4 ”when not distinguished), a coil portion 25, and a cylindrical magnetic core 6 are provided, and is a distributed constant type. It functions as a common mode noise filter (low-pass filter).

  As shown in FIG. 9, the coil portion 25 includes strip-shaped insulators 5 a and 5 b, a pair of grounding conductors 7 a and 7 b (hereinafter, also referred to as “grounding conductor 7” unless otherwise specified), Signal conductors 8a and 8b (hereinafter also referred to as “signal conductor 8” unless otherwise distinguished) are provided. In this case, each of the grounding conductors 7a and 7b is electrically connected to the grounding terminals 4a and 4b on one end side (left end side in FIG. 9). Specifically, each grounding terminal 4 is connected to a grounding site defined within one turn (outermost peripheral portion, region Y in FIG. 9) at the end of winding in each grounding conductor 7. The grounding conductors 7a and 7b are formed to have the same width and are stacked on the strip insulator 5a in a parallel state so as not to contact each other. The strip-shaped insulator 5b is stacked on the strip-shaped insulator 5a so as to sandwich the grounding conductors 7 between the strip-shaped insulator 5a. The signal conductors 8a and 8b are formed to have the same width and are placed on the strip insulator 5b in a parallel state so as not to contact each other. That is, the conductors 7 and 8 are overlaid on the strip insulator 5a with the strip insulator 5b sandwiched therebetween. In addition, input terminals 2a and 2b are electrically connected to one end sides (left end side in FIG. 9) of the signal conductors 8a and 8b, respectively. Specifically, each input terminal 2 is connected to an input portion defined within one turn (outermost peripheral portion, region Y in FIG. 9) at the end of winding in each signal conductor 8. Further, each of the signal conductors 8a and 8b has a center point W along the length direction of the signal conductors 8a and 8b (region of one third of the total length of each signal conductor 8a and 8b) X. Output terminals 3a and 3b are connected to the prescribed output parts, respectively. In this case, the connection position (output part) of each output terminal 3a, 3b to each signal conductor 8a, 8b is the same as the connection position (output part) of the output terminal 3 to the signal conductor 8 in the filter element 1. Similarly to the case, the signal conductors 8a and 8b are not limited to the center point W, and can be defined at any position in the region X centered on the center point W. The coil portion 25 is formed by winding the strip insulators 5a, 5b and the conductors 7, 8a, 8b, which are stacked on each other, on the other ends of the respective conductors, and on the signal conductors 8a, 8b. On the other hand, each grounding conductor 7 is wound so as to be on the outside, thereby forming a cylindrical shape (cylindrical shape having a gap H at the center) as shown in FIG. A magnetic core 6 is mounted in the gap H of the coil portion 25.

  In this coil part 25, each one end side in each signal conductor 8a, 8b to which each input terminal 2a, 2b is connected is located on the outer peripheral side of the coil part 25, and each input terminal 2a, 2b is shown in FIG. As shown in FIG. 7, the coil portion 25 is drawn from the outer peripheral side portion (the drawn portion A in FIG. 8) on one end face. Each of the output terminals 3a and 3b is on a plane L including the center (center axis O) of the coil portion 25 and the lead portion A of the input terminal 2, and the center axis O (or the gap H or the magnetic core 6). It is pulled out from a drawer part B located on the opposite side to the drawer part A across the pinch. One end side of each grounding conductor 7 to which each grounding terminal 4 is connected is located on the outer peripheral side of the coil part 25, and each grounding terminal 4 is connected to one of the coil parts 25 as shown in FIG. It is each pulled out from the outer peripheral side part (drawing part C in FIG. 8) in the end face. Specifically, as shown in FIG. 8, the lead-out portion C of each grounding terminal 4 is on the plane L and is opposite to the lead-out portion A across the central axis O of the coil portion 25 (in other words, , Respectively, on the opposite side of the drawing portion A across the drawing portion B).

  In this filter element 21, each signal conductor 8a is formed in a state where two signal conductors 8a and 8b arranged in parallel and two grounding conductors 7a and 7b are overlapped with each other via a strip-like insulator 5b. , 8b each coil conductor 25 is formed by winding each grounding conductor 7 so as to be outside, and each signal conductor 8a, 8b is located on the outer peripheral side of the coil section 25. The input terminals 2a and 2b are connected to input portions respectively defined on the end side (outermost peripheral portion) and drawn out from the outer peripheral side portion of the coil portion 25, respectively, and the region X on the center side of each signal conductor 8a and 8b Each output terminal 3a, 3b is connected to an output part respectively defined in the inside, and a lead part B located on the opposite side to the lead part A of each input terminal 2a, 2b across the central axis O of the coil part 25 Each lead, each grounding conductive 7, each grounding terminal 4 is connected to a grounding portion respectively defined on the end side (outermost peripheral portion) located on the outer peripheral side of the coil portion 25, and each input terminal is sandwiched between the center axis O of the coil portion 25. By pulling out from the outer peripheral side part of the coil part 25 located on the opposite side to the lead part A of 2a, 2b, the lead part B of the output terminals 3a, 3b in the coil part 25 (output in each signal conductor 8) The signal conductors 8a and 8b can be disposed on the inner peripheral side with respect to the part) in a state where the band-like insulator 5b is interposed between the conductors for grounding 7. For this reason, a part of the signal conductor 8a on the inner peripheral side of the output part 3a of the output terminal 3a is used as one electrode, and a part of each grounding conductor 7 facing the inner peripheral part is used as the other part. Capacitors serving as electrodes and portions of the grounding conductors 7 facing the inner peripheral portion of the signal conductor 8b with the inner peripheral portion of the output terminal 3b of the output conductor 3b as one electrode Can be formed between the output terminals 3a and 3b (output portions of the signal conductors 8) and the ground.

  Therefore, according to the filter element 21, a path from the input terminal 2a to the output terminal 3a via the signal conductor 8a and a path from the input terminal 2b to the output terminal 3b via the signal conductor 8b. As a result, the common mode noise that propagates simultaneously can be bypassed to the ground side via the capacitors formed on the output terminals 3a and 3b, so that the filter element 1 has an attenuation characteristic with respect to the normal mode noise. In the same way that variations can be reduced, it is possible to realize a common-mode filter element with little variation in attenuation characteristics with respect to noise, even if it is used for an output filter of a noise source that has a large output impedance variation with respect to common mode noise. it can. Further, according to the filter element 21, the signal conductors 8a, 8b, 8a, 8b are defined by defining the center point W of each of the signal conductors 8a, 8b as an output part and connecting the output terminals 3a, 3b to the output part. As a result of securing the number of turns for 8b and securing the capacitance of the capacitor, a common mode filter element with less variation in attenuation characteristics with respect to noise can be realized.

  Next, the filter element 31 according to the present invention will be described with reference to the drawings.

  First, the configuration of the filter element 31 will be described. The filter element 31 is configured as a common mode filter by changing the configuration of the signal conductor 8 of the filter element 11 that functions as a normal mode filter. For this reason, most of the components are common to the corresponding components of the filter element 11. Therefore, the same components as those of the filter element 11 are denoted by the same reference numerals, and redundant description is omitted.

  As shown in FIG. 10, the filter element 31 includes a pair of input terminals 2 (2a, 2b), a pair of output terminals 3 (3a, 3b), a pair of ground terminals 4 (4a, 4b), a coil portion 35, and The magnetic core 6 is configured to function as a distributed constant type common mode noise filter (low-pass filter).

  As shown in FIG. 12, the coil portion 35 includes strip-shaped insulators 5a and 5b, grounding conductors 7, and a pair of signal conductors 8 (8a and 8b). In this case, the signal conductors 8a and 8b are formed to have the same width and are placed on the strip insulator 5a in a parallel state so as not to contact each other. Further, the input terminals 2a and 2b are electrically connected to the other end sides (right end portions in FIG. 12) of the signal conductors 8a and 8b, respectively. Specifically, each input terminal 2 is connected to an input portion defined within one turn (innermost peripheral portion, region Y in FIG. 12) at the beginning of winding in each signal conductor 8. Further, each of the signal conductors 8a and 8b has a center point W along the length direction of the signal conductors 8a and 8b (region of one third of the total length of each signal conductor 8a and 8b) X. Output terminals 3a and 3b are connected to the prescribed output parts, respectively. In this case, the connection positions (output portions) of the output terminals 3a and 3b to the signal conductors 8a and 8b are the same as the connection positions (output portions) of the output terminals 3 to the signal conductor 8 in the filter element 11. Similarly to the case, the signal conductors 8a and 8b are not limited to the center point W, and can be defined at any position in the region X centered on the center point W. The strip insulator 5b is overlaid on the signal conductors 8a and 8b so as to sandwich the signal conductors 8a and 8b with the strip insulator 5a. Each grounding terminal 4 is electrically connected to the other end side (right end side in FIG. 12) of each grounding conductor 7. Specifically, each grounding terminal 4 is connected to a grounding portion defined in one turn (innermost peripheral portion, region Y in FIG. 12) of the winding start in each grounding conductor 7. . The grounding conductors 7a and 7b are formed to have the same width and are stacked on the strip insulator 5b in a parallel state so as not to contact each other. That is, the conductors 7a and 7b and the conductors 8a and 8b are overlapped on the strip insulator 5a with the strip insulator 5b interposed therebetween. The coil portion 35 starts winding the strip insulators 5a, 5b and the conductors 7a, 7b, 8a, 8b, which are overlapped with each other, on the other end sides of the conductors 7a, 7b, 8a, 8b. As shown in FIG. 10, the signal conductors 8a and 8b are wound around the grounding conductors 7 as a whole, thereby forming a tubular shape (a gap H is formed at the center). (Cylindrical shape). A magnetic core 6 is mounted in the gap H of the coil portion 35.

  In this coil part 35, the other end side of each signal conductor 8a, 8b to which each input terminal 2a, 2b is connected is located on the inner peripheral side of the coil part 35, and each input terminal 2a, 2b is As shown in FIG. 10, the coil portion 35 is drawn from an inner peripheral side portion (a lead portion A in FIG. 11) on one end face (upper end surface in FIG. 10). Further, the other end side of each grounding conductor 7 to which each grounding terminal 4 is connected is located on the inner peripheral side of the coil part 35, and each grounding terminal 4 is connected to the coil part as shown in FIG. 35 is pulled out from an inner peripheral side portion (drawer portion C in FIG. 11) on one end face of 35. Here, the lead portion C of each grounding terminal 4 is on a plane L including the center (center axis O) of the coil portion 35 and the lead portions A of the input terminals 2a and 2b, as shown in FIG. The input terminals 2a and 2b are respectively defined on the side opposite to the lead-out site A across the central axis O (or the gap H or the magnetic core 6). Each output terminal 3a, 3b is on a plane L including the central axis O of the coil portion 35 and the lead portion A of each input terminal 2a, 2b, and the lead portion A sandwiches the central axis O of the coil portion 35. Is pulled out from a drawing site B located on the opposite side (in other words, on the side opposite to the drawing site A across the drawing site C).

  In this filter element 31, each of the grounding conductors 7 in a state where the two signal conductors 8 a and 8 b arranged in parallel and the two grounding conductors 7 a and 7 b are overlapped via the strip-like insulator 5 b. Are provided with a coil portion 35 formed by winding the signal conductors 8a and 8b so that the signal conductors 8a and 8b are on the outside, and are located on the inner peripheral side of the coil portion 35 in the signal conductors 8a and 8b. The input terminals 2a and 2b are connected to input portions respectively defined on the respective end portions (innermost peripheral portions) and drawn out from the inner peripheral portions of the coil portions 35, and the coil portions 35 of the respective grounding conductors 7 are connected. Each grounding terminal 4 is connected to the grounding part defined on the end side (innermost circumferential part) located on the inner peripheral side, and the input terminals 2a and 2b are drawn out with the central axis O of the coil part 35 interposed therebetween. Inner peripheral side portion of the coil portion 35 located on the opposite side to the portion A The output terminals 3a and 3b are connected to output portions respectively defined in the central region X of the signal conductors 8a and 8b, and the input terminals are sandwiched between the central axes O of the coil portions 35. By pulling out from the lead-out part B located on the opposite side to the lead-out part A of 2a, 2b, the lead-out part B (output part in each signal conductor 8) of the output terminals 3a, 3b in the coil part 35. The signal conductors 8a and 8b can be disposed on the outer peripheral side in a state where the belt-like insulator 5b is interposed between the conductors for grounding 7. For this reason, a part on the outer peripheral side of the output part 3a of the output conductor 3a in the signal conductor 8a is set as one electrode, and a part in each grounding conductor 7 facing the part on the outer peripheral side is set as the other electrode. And a capacitor in which the part on the outer peripheral side of the output part 3b of the output terminal 3b in the signal conductor 8b is one electrode and the part in each grounding conductor 7 facing this part is the other electrode Can be formed between the output terminals 3a and 3b (output portions of the signal conductors 8) and the ground.

  Therefore, according to the filter element 31, a path from the input terminal 2a to the output terminal 3a via the signal conductor 8a and a path from the input terminal 2b to the output terminal 3b via the signal conductor 8b. As a result of the common mode noise that propagates at the same time can be bypassed to the ground side via the capacitors formed on the output terminals 3a and 3b, the common mode noise can be compared with the normal mode noise. Similarly to the case where the filter element 11 can reduce variations in attenuation characteristics with respect to noise, even if the filter element 11 is used for an output filter of a noise source with large fluctuations in output impedance, the common-mode filter element with less variations in attenuation characteristics with respect to noise. Can be realized. Further, according to the filter element 31, by defining the center point W of each signal conductor 8a, 8b as an output part and connecting the output terminals 3a, 3b to this output part, the signal conductors 8a, 8b, As a result of securing the number of turns for 8b and securing the capacitance of the capacitor, a common mode filter element with less variation in attenuation characteristics with respect to noise can be realized.

  The present invention is not limited to the embodiment described above. For example, in each of the filter elements 1, 11, 21, 31 described above, the magnetic core 6 is mounted inside the gap H formed in the coil portions 5, 15, 25, 35, and each grounding conductor 7 and signal Although the attenuation characteristics are improved by improving the degree of coupling of the conductors 8 and the value of distributed inductance, the coil portions 5, 15, 25, and 35 can be mounted in the pot core instead of the magnetic core 6. Moreover, the coil parts 5, 15, 25, and 35 can be formed as air-core coils without using the magnetic core 6 and the pot core.

  Further, each of the filter elements 1, 11, 21, 31 described above employs a configuration in which the input terminal 2, the output terminal 3, and the grounding terminal 4 are disposed only on the same end surface (upper end surface in FIG. 1) of the coil portion. However, the input terminal 2, the output terminal 3, and the grounding terminal 4 are only required to be disposed on the plane L including the central axis O of the coil portion. The input terminal 2, the output terminal 3, and the grounding terminal It is also possible to adopt a configuration in which some of the terminals 4 are arranged on the end surface opposite to the other terminals (the lower end surface in FIG. 1). Further, in each of the filter elements 1, 11, 21, and 31 described above, a configuration in which the input terminal 2, the output terminal 3, and the grounding terminal 4 are disposed on the plane L including the central axis O of the coil portion is employed. However, not all of the terminals are strictly arranged on the plane L, and each terminal may be arranged at a position slightly deviated from the plane L. In addition, the filter elements 21 and 31 are configured to have a pair of signal conductors 8a and 8b and function as a common mode filter, but may be configured to include three or more signal conductors. it can. In addition, the filter elements 21 and 31 employ a configuration in which the grounding conductors 7 that are independent for each of the signal conductors 8 are provided for the plurality of signal conductors 8. It is also possible to employ a configuration in which one common grounding conductor is provided for the working conductor.

  In each of the filter elements 1, 11, 21, 31 described above, the coil portions 5, 15, 25, and 35 are formed so that the strip-like insulator 5a is on the outermost side. With respect to the filter elements 1 and 21 including the coil portions 5 and 25 in which the grounding conductor 7 is located on the outside, the grounding conductor 7 is provided by disposing the strip-like insulator 5a inside the signal conductor 8. It can also be configured such that the outermost peripheral part of the coil is located on the outermost peripheral part of the coil part. According to the filter element configured as described above, the outermost peripheral portion of the grounding conductor 7 is exposed at the outermost periphery of the coil portion. For example, the grounding conductor 7 is directly connected to the ground potential of the printed circuit board. It is possible to reliably and easily ground. As an example, the filter element 41 shown in FIG. 15 is configured to include a coil part 45 configured so that the grounding conductor 7 is located on the outermost periphery based on the coil part 5 of the filter element 1. Although not shown, the band-like insulator 5a is grounded on the basis of the filter elements 11 and 31 having the coil portions 15 and 35 in which the signal conductor 8 is located outside the grounding conductor 7. By disposing inside the body 7, it is possible to configure a filter element in which the outermost peripheral portion of the signal conductor 8 is positioned on the outermost periphery of the coil portion.

1 is a perspective view showing a configuration of a filter element 1. FIG. It is the top view which looked at filter element 1 which shows each drawer part A, B, and C of input terminal 2, output terminal 3, and grounding terminal 4 from one end face. 2 is an exploded view of strip insulators 5a and 5b, grounding conductors 7 and signal conductors 8 in the filter element 1. FIG. 2 is a perspective view showing a configuration of a filter element 11. FIG. It is the top view which looked at the filter element 11 which shows each drawer | drawing-out site | part A, B, C of the input terminal 2, the output terminal 3, and the terminal 4 for grounding from one end surface. 3 is an exploded view of strip insulators 5a and 5b, grounding conductor 7 and signal conductor 8 in the filter element 11. FIG. 3 is a perspective view showing a configuration of a filter element 21. FIG. It is the top view which looked at the filter element 21 which shows each drawing-out site | part A, B, C of the input terminals 2a and 2b, the output terminals 3a and 3b, and the terminals 4a and 4b for grounding from one end surface. 4 is an exploded view of strip insulators 5a and 5b, grounding conductors 7a and 7b, and signal conductors 8a and 8b in the filter element 21. FIG. 3 is a perspective view showing a configuration of a filter element 31. FIG. It is the top view which looked at filter element 31 which shows each extraction part A, B, and C of input terminals 2a and 2b, output terminals 3a and 3b, and grounding terminals 4a and 4b from one end face. 3 is an exploded view of strip insulators 5a and 5b, grounding conductors 7a and 7b, and signal conductors 8a and 8b in the filter element 31. FIG. It is an attenuation characteristic diagram showing the relationship between the frequency of the filter element 1 and the attenuation. It is an attenuation characteristic diagram showing the relationship between the frequency of the filter element 51 and the attenuation. 3 is a perspective view showing a configuration of a filter element 41. FIG. 3 is a perspective view showing a configuration of a filter element 51. FIG.

Explanation of symbols

1, 11, 21, 31, 41 Filter element 2 Input terminal 3 Output terminal 4 Ground terminal 5, 15, 25, 35, 45 Coil portion 5a, 5b Strip insulator 6 Magnetic core 7, 7a, 7b Ground conductor 8, 8a, 8b Signal conductor H Air gap

Claims (41)

A coil portion formed in a tubular shape as a whole by winding the signal strip conductor and the ground strip conductor in a state of being overlapped via a strip insulator;
An input terminal connected to an end portion located on the outer peripheral side of the coil portion in the signal strip conductor and drawn from an outer peripheral side portion of the coil portion;
A filter element comprising: an output terminal connected in a region of one third of the total length of the signal strip conductor, centered on a central point along the length direction of the signal strip conductor.   2. The filter element according to claim 1, wherein the coil portion is formed by being wound around the signal strip conductor so that the ground strip conductor is located outside.   3. The filter element according to claim 1, wherein the output terminal is led out from a portion located on a side opposite to a lead portion of the input terminal across the center of the coil portion.   The outer circumference of the coil portion that is connected to the end portion located on the outer peripheral side of the coil portion in the grounding strip conductor and that is located on the side opposite to the lead-out portion of the input terminal across the center of the coil portion The filter element according to any one of claims 1 to 3, further comprising a grounding terminal drawn from the side portion. A coil portion formed in a tubular shape as a whole by winding the signal strip conductor and the ground strip conductor in a state of being overlapped via a strip insulator;
An input terminal connected to an end portion located on the inner peripheral side of the coil portion in the signal strip conductor and drawn from an inner peripheral portion of the coil portion;
A filter element comprising: an output terminal connected in a region of one third of the total length of the signal strip conductor, centered on a central point along the length direction of the signal strip conductor.   6. The filter element according to claim 5, wherein the coil portion is formed by being wound around the ground strip conductor so that the signal strip conductor is located outside.   The filter element according to claim 5 or 6, wherein the output terminal is led out from a portion located on a side opposite to a lead portion of the input terminal across the center of the coil portion.   The grounding strip-like conductor is connected to the end portion located on the inner peripheral side of the coil portion, and the coil portion located on the opposite side of the input terminal with respect to the center of the coil portion. The filter element according to any one of claims 5 to 7, further comprising a grounding terminal drawn out from the inner peripheral side portion.   9. The output terminal according to claim 1, wherein when the number of turns of the signal strip-shaped conductor is n, the output terminal is connected to a substantially n / 2th portion of the signal strip-shaped conductor. Filter element.   The filter element according to claim 1, wherein the output terminal is connected to the center point of the signal strip conductor. A coil portion formed in a cylindrical shape as a whole by winding a plurality of signal strip conductors arranged in parallel and a ground strip conductor through a strip insulator,
A plurality of input terminals respectively connected to the respective end portions located on the outer peripheral side of the coil portion in each of the signal strip conductors and led out from the outer peripheral side portion of the coil portion;
A plurality of output terminals respectively connected in a region of one-third of the total length of each signal strip conductor around the central point along the length direction of each signal strip conductor; Filter element.   The filter element according to claim 11, wherein the coil portion is formed by being wound around the signal strip conductors so that the ground strip conductor is outside.   13. The filter element according to claim 11, wherein each output terminal is led out from a portion located on a side opposite to a lead portion of each input terminal across the center of the coil portion.   The grounding strip-shaped conductor is connected to the end portion located on the outer peripheral side of the coil portion, and the coil portion located on the opposite side to the lead-out portion of each input terminal across the center of the coil portion. The filter element according to any one of claims 11 to 13, further comprising a grounding terminal drawn out from the outer peripheral portion. A coil portion formed in a cylindrical shape as a whole by winding a plurality of signal strip conductors arranged in parallel and a ground strip conductor through a strip insulator,
A plurality of input terminals connected to each end portion located on the inner peripheral side of the coil portion in each of the signal strip conductors and led out from the inner peripheral portion of the coil portion;
A plurality of output terminals respectively connected in a region of one-third of the total length of each signal strip conductor around each central point along the length direction of each signal strip conductor; Filter element provided.   The filter element according to claim 15, wherein the coil portion is formed by being wound around the ground strip conductor so that the signal strip conductors are located outside.   17. The filter element according to claim 15, wherein each output terminal is led out from a portion located on the opposite side of the lead portion of each input terminal across the center of the coil portion.   The coil part that is connected to the end part located on the inner peripheral side of the coil part in the grounding strip-like conductor and that is located on the opposite side of the lead part of each input terminal across the center of the coil part The filter element according to any one of claims 15 to 17, further comprising a grounding terminal that is led out from an inner peripheral side portion.   19. The device according to claim 11, wherein when the number of turns of each of the signal strip conductors is n, each of the output terminals is connected to a substantially n / 2th portion of each of the signal strip conductors. The filter element according to any one of the above.   The filter element according to any one of claims 11 to 18, wherein each of the output terminals is connected to the center point of each of the signal strip conductors. A coil portion formed in a cylindrical shape as a whole by winding a signal strip conductor and a ground strip conductor in a state of being overlapped via a strip insulator,
An input part is defined on the end side located on the outer peripheral side of the coil part in the signal strip conductor,
A filter element in which an output part is defined in a region of one third of the total length of the signal strip conductor, centered on a central point along the length direction of the signal strip conductor.   The filter element according to claim 21, wherein the coil portion is formed by being wound around the signal strip conductor so that the ground strip conductor is on the outside.   The filter element according to claim 21 or 22, wherein the output part is defined as a part located on the opposite side of the input part across the center of the coil portion.   A grounding part is defined in a part of the grounding strip-like conductor that is located on the outer peripheral side of the coil part and located on the opposite side of the input part across the center of the coil part. The filter element according to any one of claims 21 to 23. A coil portion formed in a cylindrical shape as a whole by winding a signal strip conductor and a ground strip conductor in a state of being overlapped via a strip insulator,
An input site is defined on the end side located on the inner peripheral side of the coil portion in the signal strip conductor,
A filter element in which an output part is defined in a region of one third of the total length of the signal strip conductor, centered on a central point along the length direction of the signal strip conductor.   26. The filter element according to claim 25, wherein the coil portion is formed by being wound with respect to the grounding strip conductor so that the signal strip conductor is on the outside.   27. The filter element according to claim 25 or 26, wherein the output part is defined as a part located on a side opposite to the input part across the center of the coil portion.   A grounding part is defined at a part of the grounding strip-like conductor that is located on the inner peripheral side of the coil part and located on the opposite side of the input part across the center of the coil part. The filter element according to any one of claims 25 to 27.   29. The output portion is defined by a substantially n / 2 turn portion of the signal strip conductor, where n is the number of turns of the signal strip conductor. Filter element.   The filter element according to any one of claims 21 to 28, wherein the output portion is defined at the center point of the signal strip conductor. A coil portion formed in a cylindrical shape as a whole by winding a plurality of signal strip conductors arranged in parallel and a ground strip conductor through a strip insulator,
In each of the signal strip conductors, a plurality of input portions are respectively defined on each end portion located on the outer peripheral side of the coil portion,
Filters in which a plurality of output portions are respectively defined in a region of one third of the total length of each signal strip conductor, centered on a central point along the length direction of each signal strip conductor. element.   32. The filter element according to claim 31, wherein the coil portion is formed by being wound around the signal strip conductors so that the ground strip conductor is located outside.   33. The filter element according to claim 31 or 32, wherein each of the output parts is defined as a part located on the opposite side of the input part across the center of the coil portion.   A grounding part is defined at a part of the grounding strip-like conductor that is located on the outer peripheral side of the coil part and located on the opposite side of the input part across the center of the coil part. The filter element according to any one of claims 31 to 33. A coil portion formed in a cylindrical shape as a whole by winding a plurality of signal strip conductors arranged in parallel and a ground strip conductor through a strip insulator,
A plurality of input parts are defined on each end side located on the inner peripheral side of the coil part in each of the signal strip conductors,
A filter in which a plurality of output portions are defined in a region of one third of the total length of each signal strip conductor, centered on each center point along the length direction of each signal strip conductor. element.   36. The filter element according to claim 35, wherein the coil portion is formed by being wound around the grounding strip conductor so that the signal strip conductors are on the outside.   37. The filter element according to claim 35 or 36, wherein each of the output portions is defined as a portion that is located on the opposite side of the input portion with respect to the center of the coil portion.   A grounding part is defined at a part of the grounding strip-like conductor that is located on the inner peripheral side of the coil part and located on the opposite side of the input part across the center of the coil part. The filter element according to any one of claims 35 to 37.   39. Each of the output strips is defined as a substantially n / 2-th turn in each of the signal strip conductors, where n is the number of turns of each of the strip strip conductors. The filter element according to any one of the above.   The filter element according to any one of claims 31 to 38, wherein each of the output portions is defined at the center point of each of the signal strip conductors.   The filter element according to any one of claims 1 to 40, wherein a magnetic body is disposed in a gap formed in a central portion of the coil portion.

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