JP2005102167A - Filter element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a filter element having superior damping characteristics. <P>SOLUTION: The filter element is equipped with a coil portion 5 that is wound and formed cylindrically so that a grounding electrical conductor 7 is positioned at the outside of a signaling electrical conductor 8, with the coil overlapped via belt-like insulators 5a, 5b and is arranged with a magnetic core 6 at its center portion; an input terminal 2 that is connected to the outermost circumference of the signaling electrical conductor 8 and is drawn out from a lateral side of an outer circumferential of the coil portion 5; an output terminal 3 that is connected to the innermost circumference of the signaling conductor 8 and sandwiches the magnetic core 6 and then is drawn from a lateral side of the center portion of the coil portion 5 positioned opposite to a portion, from which the input terminal 2 is drawn; and a grounding terminal 4 that is connected to the outermost circumference of the grounding electrical conductor 7 and sandwiches a portion, from which the output terminal 3 is drawn out and then is drawn from a lateral side of the outermost circumference of the coil portion 5 positioned opposite to the portion, from which the input terminal 2 is drawn. <P>COPYRIGHT: (C)2005,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 as a comparative example and an example in Japanese Patent No. 2826320 is known.

  Among them, a filter element disclosed as a comparative example (hereinafter also referred to as “filter”) includes a cylindrical winding portion (40) and one of the cylindrical winding portion (40) as shown in FIG. Three leads (34-1, 34-2, 36) provided on the end face are provided. In this case, the winding portion (40) is a laminate in which the strip conductor (30-1) and the ground strip conductor (30-2) are overlapped via the dielectric layers (32-1, 32-2). The body (see FIG. 2) is formed by winding the body around the rotary winding shaft (38) a plurality of times. On the other hand, the first inner lead (34-1) for input / output is connected to the vicinity of the inner end (left end in the figure) of the strip-shaped conductor (30-1). The first outer lead (34-2) for input / output is connected to the vicinity of the outer side of the strip-shaped conductor (30-1). Further, the grounding outer lead (36) is shifted from the first outer lead (34-2) by 1/2 turn around the winding shaft (38) in the vicinity of the outer end of the grounding strip conductor (30-2). Connected.

  With this configuration, this filter can sufficiently narrow the distance between the leads (34-2, 36) in a state where the conductors (30-1, 30-2) are developed, and thus has excellent attenuation characteristics. Can be realized. Further, in this filter, both the leads (34-2, 36) can be positioned on the substantially straight line (100) at predetermined intervals via the winding shaft center (P), so that the attenuation is substantially uniform and good. Excellent mass productivity can be realized along with the characteristics. Further, as shown in FIG. 1 (B) in the same publication, this filter has two cylindrical heating portions (40) while heating the cylindrical winding portion (40). The same effect can be obtained in a configuration in which the air core portion (42) and the winding portion (40) are deformed flat by pressing from the direction orthogonal to the wire (100) connecting the leads (34-2, 36). Can play.

  On the other hand, as shown in FIG. 4 of the same publication, the filter element disclosed as an example has a cylindrical winding portion (40) and three leads (34-1) provided on one end face thereof. , 34-2, 36) and the grounding outer lead (36) is shifted from the first outer lead (34-2) by ½ rotation around the winding shaft (38) ( The first outer lead (34-2), the grounding lead (36), and the winding axis center (P) are arranged on the straight line (100)), and are common to the filter element of the comparative example described above. On the other hand, the filter element disclosed as the embodiment is arranged such that the first inner lead (34-1) is shifted from the first outer lead (34-2) by ¼ rotation around the winding shaft (38). (The first inner lead (34-1) is arranged on the straight line (110) passing through the winding axis center P perpendicular to the straight line (100)) and different from the filter element of the comparative example described above. To do.

With this configuration, in the filter element disclosed as the embodiment, the distance between the leads (34-2, 36) in a state where the conductors (30-1, 30-2) are developed can be sufficiently narrowed. Excellent damping characteristics can be realized. Furthermore, in this filter element, when the winding portion (40) is deformed flat, the first inner lead (34-1) can be positioned at substantially the same position as the winding axis center (P). The ground lead (36) and the first outer lead (34-2) can be arranged symmetrically about the winding axis center (P), that is, the first inner lead (34-1). Therefore, the physical connections between the first outer lead (34-2) and the first inner lead (34-1) and between the first inner lead (34-1) and the grounding lead (36). Since a sufficient interval is obtained, it is possible to effectively avoid a short circuit due to work such as wiring and soldering. Therefore, the filter element can be easily attached to the printed circuit board.
Japanese Patent No. 2826320 (page 3-5, FIGS. 1, 2 and 4)

  However, the same type of air-core device has a small effect on low-frequency noise such as noise generated from a switching power supply. In addition, it has been desired to realize a filter element having further excellent attenuation characteristics. Therefore, in order to meet such demands, the inventor of the present application has independently conducted research on this type of filter element, and as a result, a filter having a further excellent attenuation characteristic by arranging each lead in a specific arrangement. It has been found that the device can be realized.

  The present invention has been made in view of the above-described demand, and has as its main object to provide a filter element having excellent attenuation characteristics.

  In order to achieve the above object, the filter element according to claim 1, wherein the signal strip conductor and the ground strip conductor are overlapped via the strip insulator and the signal strip conductor is grounded. By winding the strip conductor to the outside, it is connected to the coil portion that is formed into a cylindrical shape as a whole and has a magnetic body disposed at the center, and the outermost peripheral portion of the signal strip conductor. And connected to the innermost peripheral portion of the signal strip-shaped conductor and positioned on the opposite side of the input terminal with the magnetic material interposed therebetween. An output terminal drawn from the center side portion of the coil portion, and connected to the outermost peripheral portion of the grounding strip conductor, and on the opposite side to the lead portion of the input terminal across the lead portion of the output terminal The corresponding co And a ground terminal drawn out from the outer peripheral side portion of the pole tip. 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.

  According to a second aspect of the present invention, the signal strip conductor is connected to the ground strip conductor in a state where the signal strip conductor and the ground strip conductor are overlapped via the strip insulator. By being wound so as to be on the outside, it is formed into a cylindrical shape as a whole, and is connected to the innermost peripheral portion of the signal strip-shaped conductor, while being connected to the coil portion in which the magnetic body is disposed at the central portion. An input terminal drawn out from the central part of the coil part, and the coil connected to the innermost peripheral part of the grounding strip-like conductor and located on the opposite side of the input part from the lead part across the magnetic body A grounding terminal pulled out from the center side part of the signal line, and connected to the outermost peripheral part of the signal strip-shaped conductor and positioned on the opposite side of the lead-out part of the input terminal across the lead-out part of the grounding terminal Outside the coil section And an output terminal led out from the side portion.

  According to a third aspect of the present invention, there is provided the filter element according to claim 3, wherein the pair of signal strip conductors and the ground strip conductor are overlapped via the strip insulator, with respect to the pair of signal strip conductors. A coil part formed as a whole by being wound so that the belt-like conductor is on the outside and having a magnetic body disposed at the center, and each outermost peripheral part of the pair of signal strip-like conductors And a pair of input terminals each drawn from an outer peripheral side portion of the coil portion, and connected to each innermost peripheral portion of the pair of signal strip conductors and sandwiching the magnetic body A pair of output terminals each drawn from the center side portion of the coil portion located on the opposite side to the lead portion of the input terminal, and connected to the outermost peripheral portion of the grounding belt-like conductor and the pair of output terminals Sandwich the drawer In the pull-out portion of said pair of input terminals and a ground terminal drawn out from the outer peripheral side portion of the coil portion located on the opposite side.

  According to a fourth aspect of the present invention, there is provided the filter element according to the present invention, wherein the pair of signal strip conductors and the ground strip strip conductor are overlapped via the strip insulator and the pair of signal strips are connected to the ground strip conductor. A coil portion formed as a whole by being wound so that the strip conductor is on the outside and having a magnetic body disposed at the center, and the innermost circumferences of the pair of signal strip conductors A pair of input terminals that are connected to each other and drawn out from a central portion of the coil part, and a pair of input terminals that are connected to the innermost peripheral part of the grounding strip-shaped conductor and sandwich the magnetic body A grounding terminal led out from the central part of the coil portion located on the opposite side to the lead-out part of the coil, and connected to the outermost peripheral parts of the pair of signal strip conductors and the lead-out part of the grounding terminal Insert the pair The drawer part of the terminals and a pair of output terminals drawn from each of the outer peripheral side portion of the coil portion located on the opposite side.

  The filter element according to claim 5 is the filter element according to claim 1 or 3, wherein the number of turns of the signal strip conductor is n (n is a number of 2 or more). The body is wound in a state in which the number of turns is defined as 1 or more and (n-1) or less, and the end of the outermost peripheral part is aligned with the end of the outermost peripheral part of the signal strip conductor. Yes.

  The filter element according to claim 6 is the filter element according to claim 2 or 4, wherein the number of turns of the signal strip conductor is n (n is a number of 2 or more). The body is wound in a state in which the number of turns is defined as 1 or more and (n-1) or less, and the end of the innermost circumference is aligned with the end of the innermost circumference of the signal strip conductor. Has been.

  The filter element according to claim 7 is the filter element according to any one of claims 1 to 6, wherein the lead-out part of the input terminal, the lead-out part of the output terminal, and the lead-out part of the ground terminal are It is located on the same plane including the central axis of the coil part.

  According to the filter element of the first aspect, the grounding strip-shaped conductor is wound around the signal strip-shaped conductor so as to be on the outside, thereby forming a cylindrical shape as a whole, and the magnetic body at the center. Connected to the arranged coil portion, the outermost peripheral portion of the signal strip conductor and the input terminal drawn from the coil portion, and connected to the innermost periphery portion of the signal strip conductor and sandwiching the magnetic body The output terminal drawn from the central part of the coil part located on the opposite side to the lead part of the input terminal and the input terminal connected to the outermost peripheral part of the grounding strip conductor and sandwiching the lead part of the output terminal Provided with a grounding terminal drawn from the outer peripheral part of the coil portion located on the opposite side of the lead part of the coil, so that a large amount of attenuation can be secured in a predetermined frequency band. It is possible to realize a filter element for the normal mode with.

  Further, according to the filter element of the second aspect, the signal strip conductor is wound around the ground strip conductor so as to be on the outside, so that it is formed into a cylindrical shape as a whole and is magnetic at the center. Connected to the innermost peripheral portion of the signal strip-shaped conductor and connected to the innermost peripheral portion of the ground strip-shaped conductor and magnetically connected to the innermost peripheral portion of the signal strip-shaped conductor. A grounding terminal pulled out from the center side part of the coil part located on the opposite side of the input terminal drawing part across the body, and a leading part of the grounding terminal connected to the outermost peripheral part of the signal strip conductor As a result, it is possible to ensure a large amount of attenuation in a predetermined frequency band by providing an output terminal drawn from the outer peripheral side part of the coil portion located on the opposite side of the input terminal drawing part. It is possible to realize a filter element for the normal mode with a damping properties.

  Further, according to the filter element of the third aspect, the grounding strip conductor is wound around the pair of signal strip conductors so as to be on the outside, and is formed into a cylindrical shape as a whole and has a central portion. And a pair of input terminals connected to the outermost peripheral portions of the pair of signal strip conductors and drawn from the coil sections, respectively, and a pair of signal strip conductors A pair of output terminals that are connected to the innermost periphery and that are respectively pulled out from the central side portion of the coil portion that is located on the opposite side of the lead portion of the pair of input terminals across the magnetic body, and A grounding terminal that is connected to the outermost peripheral portion and that is led out from the outer peripheral side portion of the coil portion that is located on the opposite side of the outgoing portion of the pair of input terminals with the outgoing portion of the pair of output terminals interposed therebetween; , Place It results it is possible to ensure a large attenuation in the frequency band, it is possible to realize a filter element for common mode having excellent attenuation characteristics.

  Further, according to the filter element of the fourth aspect, the pair of signal strip conductors are wound around the ground strip conductor so as to be on the outside, thereby forming a cylindrical shape as a whole and the center portion. And a pair of input terminals connected to the innermost peripheral portions of the pair of signal strip conductors and drawn from the coil sections respectively, and the innermost portion of the ground strip conductor A grounding terminal that is connected to the peripheral portion and is located on the opposite side of the lead portion of the pair of input terminals across the magnetic body, and each of the pair of signal strip conductors. By providing a pair of output terminals that are connected to the outer peripheral portion and that are respectively pulled out from the outer peripheral side portion of the coil portion that is located on the opposite side of the drawing portion of the pair of input terminals across the lead portion of the grounding terminal The given It results it is possible to ensure a large attenuation in the frequency band, it is possible to realize a filter element for common mode having excellent attenuation characteristics.

  According to the filter element of claim 5, when the number of turns of the signal strip conductor is n (n is a number of 2 or more), the number of turns of the ground strip conductor is 1 or more (n−1). The grounding conductor having the same length is obtained by winding the grounding strip conductor with the end of the outermost peripheral portion being aligned with the end of the outermost periphery of the signal strip-shaped conductor. As compared with the configuration using the signal conductor, the number of turns of the signal conductor can be increased even when the same pot core or the same magnetic core is used. For this reason, according to this filter element, the noise reduction effect in a lower frequency band can be improved by the increase in distributed inductance.

  According to the filter element of claim 6, when the number of turns of the signal strip conductor is n (n is a number of 2 or more), the number of turns of the ground strip conductor is 1 or more (n−1). As specified below, the grounding strip conductor is wound with the end of the innermost periphery aligned with the end of the innermost periphery of the signal strip conductor. Compared to the configuration using the conductor and the signal conductor, the number of turns of the signal conductor can be increased even when the same pot core or the same magnetic core is used. For this reason, according to this filter element, the noise reduction effect in a lower frequency band can be improved by the increase in distributed inductance.

  According to the filter element of claim 7, by positioning the lead-out part of the input terminal, the lead-out part of the output terminal and the lead-out part of the grounding terminal on the same plane including the central axis of the coil part, As a result of securing a larger amount of attenuation in a predetermined frequency band, a filter element for normal mode or common mode having more excellent attenuation 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 best mode)
First, the filter element 1 according to the present embodiment 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 grounding terminal 4, a coil part 5, and a columnar (columnar as an example) magnetic body (magnetic core) 6. It functions as a distributed constant type three-terminal noise filter (low-pass normal mode filter).

  As shown in FIG. 3, the coil portion 5 includes, for example, strip-shaped insulators 5a and 5b formed to have the same width, and a strip-shaped conductor 7 for grounding and a signal formed narrower than the strip-shaped insulators 5a and 5b. A strip-shaped conductor 8 is provided. In this case, each strip insulator 5a, 5b is made of a material having dielectric properties and electrical insulation properties. One end of the grounding terminal 4 is electrically connected to one end of the grounding strip-like conductor (hereinafter also referred to as “grounding conductor”) 7. In addition, the grounding conductor 7 is overlaid on the strip-like insulator 5a so as to be positioned at the center of the strip-like insulator 5a in the width direction. The strip insulator 5b is overlaid on the strip insulator 5a so that the grounding conductor 7 is sandwiched between the strip insulator 5a. On the other hand, the signal strip conductor 8 (hereinafter also referred to as “signal conductor”) is set to the same length as the ground conductor 7 and one end side of the input terminal 2 is electrically connected to one end side thereof. In addition, one end side of the output terminal 3 is electrically connected to the other end side. The signal conductor 8 is positioned on the strip insulator 5b at the center of the strip insulator 5b in the width direction, and the positions of the end portions are the positions of the end portions of the ground conductor 7. They are layered together. That is, the conductors 7 and 8 are overlaid on the strip insulator 5a with the strip insulator 5b sandwiched therebetween. The coil section 5 is configured such that the band-like insulators 5a and 5b and the conductors 7 and 8 that are overlapped with each other in this manner, with the other ends of the conductors 7 and 8 starting to be wound, and the signal conductor 8 1 so that the number of turns of the grounding conductor 7 and the signal conductor 8 is the same, for example, as shown in FIG. It is formed in 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 case, one end side (outermost peripheral portion) of the signal conductor 8 to which the input terminal 2 is connected is positioned on the outer peripheral side of the coil portion 5 in a state where it is substantially aligned with one end side of the grounding conductor 7. As shown in FIG. 1, the terminal 2 is drawn from an outer peripheral side portion (a lead portion A in FIG. 2) on one end face (upper end surface in the drawing) of the coil portion 5. On the other hand, the other end side (innermost peripheral portion) of the signal conductor 8 to which the output terminal 3 is connected is substantially aligned with the other end side of the grounding conductor 7, so that the center side (inner peripheral side) of the coil portion 5. ), The output terminal 3 is led out from a central part (drawing part B in FIG. 2) on one end face of the coil part 5, as shown in FIG. Here, the extraction part B of the output terminal 3 is, as shown in FIG. 2, a virtual plane L (hereinafter also referred to as “plane L”) including the central axis O of the coil portion 5 and the extraction part A of the input terminal 2. The upper side is set on the opposite side to the drawing portion A across the central axis O (magnetic core 6). In addition, one end side (outermost peripheral portion) of the grounding conductor 7 to which the grounding terminal 4 is connected is located on the outer peripheral side of the coil portion 5, and the grounding terminal 4 is connected to the coil portion as shown in FIG. 1. 5 is pulled out from an outer peripheral side portion (drawer portion C in FIG. 2) on one end face of the member 5. Specifically, as shown in FIG. 2, the lead-out part C of the ground terminal 4 is set on the plane L and on the opposite side of the lead-out part A across the lead-out part B. Here, the “drawer 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 where the input terminal 2 or the like protrudes from the coil part 5. Therefore, the coil portion 5 is accommodated in a pot core (magnetic material) or the like, and the portion where the input terminal 2 or the like is pulled out from the pot core is different from the portion where the input terminal 2 or the like is pulled out from the coil portion 5. The part pulled out from the part 5 is the “drawing part” of the input terminal 2 or the like. Similarly, when connecting the input terminal 2 and the like drawn out from the coil unit 5 to the bobbin leg, the part drawn out from the coil unit 5 becomes the “draw-out part” of the input terminal 2 and the like. Therefore, it is not necessary to dispose the bobbin foot on the plane L, and the bobbin foot can be disposed at an arbitrary position.

  According to this filter element 1, the grounding conductor 7 is wound around the signal conductor 8 so as to be on the outside, and is formed into a cylindrical shape as a whole, and the magnetic core 6 is disposed at the center. Connected to the outermost peripheral portion of the coil portion 5, the signal conductor 8, and to the input terminal 2 drawn from the outer peripheral side portion (the lead portion A) of the coil portion 5, and to the innermost peripheral portion of the signal conductor 8 An output terminal 3 that is connected and is pulled out from a central side portion (extraction portion B) of the coil portion 5 that is located on the opposite side of the extraction portion A of the input terminal 2 across the magnetic core 6, and a grounding conductor 7 A grounding terminal 4 connected to the outermost peripheral portion and drawn from an outer peripheral side portion (leading portion) of the coil portion 5 located on the opposite side of the drawing portion A of the input terminal 2 across the lead portion B of the output terminal 3. In FIG. As shown by the symbol P, a large attenuation amount (attenuation amount of 50 dB or more) can be ensured in a predetermined frequency band (about 1.5 MHz to 15 MHz in the figure). As a result, for a normal mode having excellent attenuation characteristics The filter element can be realized.

(Second best mode)
Next, the configuration of the filter element 11 according to this embodiment 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 grounding terminal 4, a coil portion 15, and a columnar magnetic core 6, and is a distributed constant type three-terminal noise. Functions as a filter (low-pass normal mode filter).

  As shown in FIG. 6, the coil portion 15 includes strip-shaped insulators 5 a and 5 b and conductors 7 and 8. In this case, one end side of the output terminal 3 is electrically connected to one end side of the signal conductor 8 and one end side of the input terminal 2 is electrically connected to the other end side. Further, 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. On the other hand, the grounding conductor 7 is set to the same length as the signal conductor 8, and one end side of the grounding terminal 4 is electrically connected to the other end side. The grounding conductor 7 is positioned on the strip-shaped insulator 5b at the center in the width direction of the strip-shaped insulator 5b, and the positions of the respective end portions are the positions of the respective end portions of the signal conductor 8. They are layered together. 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 is composed of the strip-like insulators 5a and 5b and the conductors 7 and 8 stacked on each other in this manner, with the other end side of each conductor 7 and 8 starting to be wound, and the grounding conductor 7 Is wound so that the signal conductor 8 is on the outer side, so that the ground conductor 7 and the signal conductor 8 have the same number of turns, for example, and a cylinder in which a gap H is formed in the center. It is formed in a shape. A magnetic core 6 is mounted in the gap H of the coil portion 15.

  In this case, the other end side (innermost peripheral portion) of the signal conductor 8 to which the input terminal 2 is connected is positioned on the inner peripheral side of the coil portion 15 in a state where it is substantially aligned with the other end side of the grounding conductor 7. Then, as shown in FIG. 4, the input terminal 2 is drawn out from a central side portion (a drawing portion A in FIG. 5) on one end face of the coil portion 15. In addition, the other end side (innermost peripheral portion) of the grounding conductor 7 to which the grounding terminal 4 is connected is located on the center side (inner peripheral side) of the coil portion 15. As shown in FIG. 5, the coil portion 15 is drawn from the center side portion (the drawing portion C in FIG. 5) on one end face. 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. It is set on the opposite side of the lead portion A of the input terminal 2 across the core 6). Further, one end side (outermost peripheral portion) of the signal conductor 8 to which the output terminal 3 is connected is positioned on the outer peripheral side of the coil portion 15 in a state where it is substantially aligned with one end side of the grounding conductor 7. As shown in FIG. 4, 3 is pulled out from the outer peripheral side part (drawing part B in FIG. 5) on one end face of the coil part 15. Specifically, as shown in FIG. 5, the lead-out part B of the output terminal 3 is on the plane L and is opposite to the lead-out part A of the input terminal 2 across the lead-out part C of the grounding terminal 4. Is set to

  According to this filter element 11, the signal conductor 8 is wound around the grounding conductor 7 so as to be outside, and is formed into a cylindrical shape as a whole, and the magnetic core 6 is disposed at the center. The coil portion 15, the input terminal 2 connected to the innermost peripheral portion of the signal conductor 8 and drawn from the central side portion (leading portion A) of the coil portion 15, and the innermost peripheral portion of the grounding conductor 7 And a grounding terminal 4 drawn from a central part (drawing part C) of the coil portion 15 located on the opposite side of the drawing part A of the input terminal 2 across the magnetic core 6, and a signal conductor 8 is connected to the outermost periphery of the coil 8 and is drawn out from the outer peripheral side portion (the lead-out portion B) of the coil portion 15 located on the opposite side of the lead-out portion A of the input terminal 2 across the lead-out portion C of the grounding terminal 4. By providing the output terminal 3, As indicated by reference numeral R in FIG. 20, a large attenuation amount (attenuation amount of 50 dB or more) can be secured in a predetermined frequency band (about 0.7 MHz to 6 MHz in the figure). As a result, normal having excellent attenuation characteristics A mode filter element can be realized.

  The present invention is not limited to the configuration described above. For example, in each filter element 1, 11 described above, the magnetic core 6 is mounted inside the gap H formed in the coil portions 5, 15, and the coupling degree and distribution of each grounding conductor 7 and signal conductor 8. Although the example in which the attenuation characteristic is improved by increasing the inductance value has been described, a configuration in which the coil portions 5 and 15 are mounted in the pot core instead of the magnetic core 6 may be employed. According to this configuration, it is possible to reduce the influence of the external magnetic field on the coil portions 5 and 15 while further improving the degree of coupling and the distribution inductance of each grounding conductor 7 and the signal conductor 8. In this case, pot cores of various shapes shown in FIGS. 7 to 9 can be used as the pot core. In the filter element 21 using the pot core 26 shown in FIG. 7, the input terminal 2, the output terminal 3, and the grounding terminal 4 are drawn out from the cutout portion of the pot core 26.

  On the other hand, like the filter element 31 shown in FIG. 8, the lead end faces (upper end face in the figure) of the input terminal 2, the output terminal 3 and the ground terminal 4 in the coil part (the coil part 5 in the figure as an example). When the pot core 36 having a configuration in which a notch or an opening is not initially present on the wall surface facing the coil portion 5 is made to correspond to the lead-out portions A, B, and C of the input terminal 2, the output terminal 3, and the grounding terminal 4 in the coil portion 5. Then, holes 36 a, 36 b, and 36 c are formed in the wall surface of the pot core 36, and the input terminal 2, the output terminal 3, and the grounding terminal 4 are drawn out of the pot core 36.

  Furthermore, like the filter element 41 shown in FIG. 9, a notch portion or a notch portion is formed on the wall surface of the coil portion (coil portion 5 in the figure as an example) facing the lead-out end surfaces of the input terminal 2, the output terminal 3, and the grounding terminal 4. When a pot core 46 having a configuration in which an opening does not exist and a notch (opening) 46a is provided only on the peripheral wall, the pot core 46 is pulled out from a predetermined position (withdrawal sites A, B, C) in the coil portion 5. By extending the input terminal 2, the output terminal 3 and the grounding terminal 4 to the outer peripheral side of the coil part 5 along the end face of the coil part 5 as shown in FIG. 10, as shown in FIG. It is configured to be drawn out of the pot core 46 through a portion (opening) 46a. In addition, although not shown, it is needless to say that pot cores having shapes other than the above-described pot cores 26, 36, 46 can be used.

(Third best mode)
Next, the filter element 51 according to this embodiment will be described with reference to the drawings.

  First, the configuration of the filter element 51 will be described. The filter element 51 is configured to function as a common mode filter based on 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. 11, the filter element 51 includes a pair of input terminals 2a and 2b (hereinafter also referred to as “input terminal 2” when not distinguished from each other) and a pair of output terminals 3a and 3b (hereinafter referred to as “output terminals when not distinguished from each other). 3 ”), the grounding terminal 4, the coil portion 55, and the columnar magnetic core 6, and function as a distributed constant type common mode noise filter (low-pass filter).

  As shown in FIG. 12, the coil portion 55 includes strip insulators 5a and 5b, a grounding conductor 7, and a pair of signal conductors 8a and 8b (hereinafter referred to as “signal conductor 8” unless otherwise specified). Say). In this case, the grounding conductor 7 is overlapped on the strip-shaped insulator 5a with one end of the grounding terminal 4 electrically connected to one end thereof. The signal conductors 8a and 8b are formed to have the same width as an example, and are set to have the same length as the grounding conductor 7, respectively. Further, the signal conductors 8a and 8b do not come into contact with each other on the band-like insulator 5b superimposed on the band-like insulator 5a so as to sandwich the grounding conductor 7 between the band-like insulator 5a. Are parallel to each other so that the positions of the respective end portions are aligned with the positions of the respective end portions of the grounding conductor 7. In addition, each signal conductor 8a, 8b is electrically connected to one end side of each of the input terminals 2a, 2b at one end side, and electrically connected to one end side of the output terminals 3a, 3b at each other end side. Are connected to each. That is, the conductors 7 and 8 are overlaid on the strip insulator 5a with the strip insulator 5b sandwiched therebetween. The coil portion 55 is configured to start winding the strip insulators 5a, 5b and the conductors 7, 8a, 8b, which are overlapped with each other, on the other end side of the conductors 7, 8a, 8b, and The grounding conductor 7 and the signal conductors 8a and 8b have the same number of turns, for example, by winding the grounding conductor 7 on the outside of the grounding conductors 8a and 8b. As shown in FIG. 11, it is formed in a cylindrical shape (cylindrical shape with a gap H formed in the center). A magnetic core 6 is mounted in the gap H of the coil portion 15.

  In this case, one end side (outermost peripheral portion) of each signal conductor 8a, 8b to which each input terminal 2a, 2b is connected is substantially aligned with one end side of the grounding conductor 7, and the coil portion 55 As shown in FIG. 2, the input terminals 2 a and 2 b are located on the outer peripheral side and are drawn out from the lead-out portion A in the coil portion 55 in the same manner as the filter element 1. On the other hand, the other end side (innermost peripheral portion) of each of the signal conductors 8a and 8b to which the output terminals 3a and 3b are connected is substantially aligned with the other end side of the grounding conductor 7 in the coil portion. The output terminals 3a and 3b are located on the center side of 55, and are pulled out from the lead-out portion B in the coil section 55 as shown in FIG. Further, the grounding terminal 4 is drawn out from the lead-out portion C in the coil portion 55 as shown in FIG.

  According to this filter element 51, the path from which the common mode noise leads from the input terminal 2a to the output terminal 3a via the signal conductor 8a, and the output terminal 3b from the input terminal 2b via the signal conductor 8b. And both of the paths to reach the ground simultaneously and flow into the grounding conductor 7. For this reason, the pair of input terminals 2a and 2b, the pair of signal conductors 8a and 8b, and the pair of output terminals 3a and 3b are respectively one input terminal 2 and one signal conductor 8 with respect to common mode noise. And can be regarded as one output terminal 3. Accordingly, the filter element 51 functions to exhibit a good attenuation characteristic with respect to the common mode noise in the same manner as the filter element 1 functions to exhibit a good attenuation characteristic with respect to the normal mode noise.

(4th best form)
Next, the filter element 61 according to the present embodiment will be described with reference to the drawings.

  First, the configuration of the filter element 61 will be described. The filter element 61 is configured to function as a common mode filter based on the filter element 11 that functions as a normal mode filter. For this reason, many components common to the filter element 11 are provided. Since the filter element 61 is configured to function as a common mode filter like the filter element 51, the filter element 61 includes many components in common with the filter element 51. Therefore, the same components as those of the filter element 11 and the filter element 51 are denoted by the same reference numerals, and redundant description is omitted.

  As shown in FIG. 13, the filter element 61 includes a pair of input terminals 2 (2a, 2b), a pair of output terminals 3 (3a, 3b), a grounding terminal 4, a coil portion 65, and a columnar magnetic core 6. And a distributed constant type common mode noise filter (low-pass filter).

  As shown in FIG. 14, the coil section 65 includes strip-shaped insulators 5a and 5b, a grounding conductor 7, and a pair of signal conductors 8a and 8b. In this case, each of the signal conductors 8a and 8b is electrically connected to one end side of each output terminal 3a and 3b, and one end side of each input terminal 2a and 2b is electrically connected to the other end side. And is overlaid on the strip insulator 5a. Each of the signal conductors 8 a and 8 b is formed to have the same width as an example, and is set to have the same length as the signal conductor 8. The grounding conductor 7 has a position of each end on the strip-like insulator 5b that is superimposed on the strip-like insulator 5a so as to sandwich the pair of signal conductors 8a and 8b between the strip-like insulator 5a. Are stacked so as to be aligned with the positions of the end portions of the signal conductors 8a and 8b. That is, the conductors 7 and 8 are overlaid on the strip insulator 5a with the strip insulator 5b sandwiched therebetween. The coil portion 65 is formed by grounding the strip insulators 5a, 5b and the conductors 7, 8a, 8b, which are overlapped with each other, with the other end of each conductor 7, 8a, 8b starting to wind. The signal conductors 8a and 8b are wound around the signal conductor 7, so that the ground conductor 7 and the signal conductors 8a and 8b have the same number of turns, for example, As shown in FIG. 13, it is formed in a cylindrical shape (cylindrical shape with a gap H formed in the center). A magnetic core 6 is mounted in the gap H of the coil portion 15.

  In this case, each of the signal conductors 8a and 8b to which the input terminals 2a and 2b are connected has its other end side (innermost peripheral portion) substantially aligned with the other end side of the grounding conductor 7 in the coil. As shown in FIG. 5, the input terminals 2 a and 2 b are located on the center side of the portion 65 and are drawn out from the lead-out portion A in the coil portion 65 in the same manner as the filter element 11. On the other hand, one end side (outermost peripheral part) of each signal conductor 8a, 8b to which each output terminal 3a, 3b is connected is substantially aligned with one end side of the grounding conductor 7, and the outer periphery of the coil part 65 Each of the output terminals 3a and 3b is drawn out from the lead-out portion B in the coil portion 65 as shown in FIG. Further, the grounding terminal 4 is pulled out from the lead-out portion C in the coil portion 65 as shown in FIG.

  According to this filter element 61, with respect to common mode noise, as with the filter element 51, the pair of input terminals 2a and 2b, the pair of signal conductors 8a and 8b, and the pair of output terminals 3a and 3b are respectively connected. It can be regarded as one input terminal 2, one signal conductor 8 and one output terminal 3. Therefore, the filter element 61 functions to exhibit a good attenuation characteristic with respect to the common mode noise in the same manner as the filter element 11 functions to exhibit a good attenuation characteristic with respect to the normal mode noise.

  Although not shown, the filter elements 51 and 61 can of course use pot cores (for example, pot cores 26, 36, and 46 shown in FIGS. 7 to 9) instead of the magnetic core 6. is there.

  In each of the filter elements 1 to 61 described above, the input terminal 2, the output terminal 3, and the grounding terminal 4 are arranged only on the same end surface (upper end surface in FIG. 1) of the coil portion. Since the terminal 2, the output terminal 3 and the grounding terminal 4 need only be disposed on the plane L including the central axis O of the coil portion, one of the input terminal 2, the output terminal 3 and the grounding terminal 4 is included. It is also possible to adopt a configuration in which the terminal of the portion is disposed on the end surface (the lower end surface in FIG. 1) opposite to the other terminals. Further, in each of the filter elements 1 to 61 described above, the 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 adopted. Are not strictly disposed on the plane L, and the terminals may be disposed at positions slightly deviated from the plane L. In this case, although the attenuation characteristics are slightly lowered as compared with the filter elements 1 to 61 described above, the attenuation characteristics are still sufficiently good as compared with the conventional filter elements. In other words, by disposing the input terminal 2, the output terminal 3, and the grounding terminal 4 on the plane L including the central axis O of the coil portion, it is possible to secure a larger attenuation in a predetermined frequency band. As a result, it is possible to realize a normal mode or common mode filter element having even better best attenuation characteristics. Each filter element 1 to 61 is configured by mounting the magnetic core 6 in the gap H of the coil portions 5, 15, 55, 65 or using the pot cores 26, 36, 46. The filter element can be configured as an air core type that does not use the magnetic core 6 and the pot cores 26, 36, and 46. However, by attaching the columnar magnetic core 6 to the air gap H, it is possible to improve the coupling degree and the value of the distributed inductance of the grounding strip insulator 5a and the signal strip insulator 5b. A filter element having attenuation characteristics and capable of attenuating lower frequency noise can be realized. Further, although the filter elements 51 and 61 have been described with respect to the configuration in which the pair of signal conductors 8a and 8b are provided to function as a common mode filter, the filter elements 51 and 61 may be configured to include three or more signal conductors.

  Further, the present inventor greatly increases the noise reduction effect in the lower frequency band by increasing the number of turns of the signal conductor 8 and increasing the distributed inductance in each of the filter elements 1, 11, 51, 61 described above. I found that I could improve it. However, even if the number of turns of the signal conductor 8 is increased, in each of the filter elements 1, 11, 51 and 61 described above, the inner diameter of the pot core to be used and the window of a magnetic core such as an EI type, EE type or toroidal core are used. As a result of the outer diameter of the coil portions 5, 15, 55, 65 being restricted by the area, it is difficult to increase the number of turns of the signal conductor 8. In such a case, the grounding conductor 7 of the grounding conductor 7 and the signal conductor 8 is formed short to reduce the number of turns, and the signal conductor 8 is formed long to form the grounding conductor. By adopting a configuration in which the number of turns of the signal conductor 8 is increased by utilizing the gap generated in the pot core or the magnetic core window due to the decrease in the number of turns, the grounding conductor 7 having the same length and Compared to the configuration using the signal conductor 8, the number of turns of the signal conductor 8 can be increased even when the same pot core or the same magnetic core is used. For this reason, according to this filter element, the noise reduction effect in a lower frequency band can be improved by the increase in distributed inductance.

  Specifically, the filter element 71 in which the number of turns of the signal conductor 8 is increased by applying the above configuration to the filter element 1 for the normal mode will be described. In addition, about the component same as the filter element 1, the same code | symbol is attached | subjected and the overlapping description is abbreviate | omitted. As shown in FIG. 1, the filter element 71 includes an input terminal 2, an output terminal 3, a grounding terminal 4, a coil unit 75, and a magnetic core 6, as in the case of the filter element 1. The lead-out portions A, B, and C of the terminal 2, the output terminal 3, and the grounding terminal 4 are set as shown in FIG. In this case, as shown in FIG. 15, the coil portion 75 includes a grounding conductor 7 formed shorter by a length L2 than a length L1 of the grounding conductor 7 in the coil portion 5 and a signal conductor in the coil portion 5. And a signal conductor 8 formed longer than the length L1 of the conductor 8 (for example, longer by a length equal to the length L2). In addition, the coil portion 75 sandwiches the belt-like insulator 5b, and is grounded in a state where the positions of the end portions on the outermost peripheral portion side (end portion on the winding end side, left end portion in the figure) are aligned. The conductor 7 for signal and the conductor 8 for signal are wound around the signal conductor 8 so that the grounding conductor 7 is on the outside and formed into a cylindrical shape having the same outer diameter as the outer diameter of the coil portion 5. ing. In the coil portion 75 thus formed, the grounding conductor 7 is formed short and the outer diameter is, for example, the same as the outer diameter of the coil portion 5 (the outer diameter exceeds the outer diameter of the coil portion 5). By increasing the length of the signal conductor 8 (within a range), the number of turns of the signal conductor 8 can be increased as compared with the coil portion 5 while making it possible to use a pot core or magnetic core for the coil portion 5. Can do. In this case, in order to obtain a sufficient effect by forming the signal conductor 8 long, when the number of turns of the signal conductor 8 is n (n is a number of 2 or more, the same applies hereinafter) It is preferable that the number of turns of the electric conductor 7 is 1 or more and (n-1) or less.

  Next, the filter element 81 in which the number of turns of the signal conductor 8 is increased by applying the above configuration to the filter element 11 for the normal mode will be described. In addition, about the component same as the filter element 11, the same code | symbol is attached | subjected and the overlapping description is abbreviate | omitted. As shown in FIG. 4, the filter element 81 includes an input terminal 2, an output terminal 3, a grounding terminal 4, a coil portion 85, and a magnetic core 6 in the same manner as the filter element 11. The lead portions A, B, and C of the terminal 2, the output terminal 3, and the grounding terminal 4 are set as shown in FIG. In this case, as shown in FIG. 16, the coil portion 85 includes the grounding conductor 7 formed shorter than the length L1 of the grounding conductor 7 in the coil portion 15 by the length L2 and the signal conductor in the coil portion 15. And a signal conductor 8 formed longer than the length L1 of the conductor 8 (for example, longer by a length equal to the length L2). In addition, the coil portion 85 is overlapped with the strip-like insulator 5b sandwiched between them and the positions of the end portions on the innermost peripheral side (the winding start side end portion, the right end portion in the figure) being aligned. The grounding conductor 7 and the signal conductor 8 are wound around the grounding conductor 7 so that the signal conductor 8 is on the outside and formed into a cylindrical shape having the same outer diameter as the outer diameter of the coil portion 15. Has been. In the coil portion 85 formed in this manner, the grounding conductor 7 is formed short and the outer diameter is, for example, the same as the outer diameter of the coil portion 15 (the outer diameter exceeds the outer diameter of the coil portion 15). By increasing the length of the signal conductor 8 (within a range), the number of turns of the signal conductor 8 can be increased as compared with the coil portion 15 while making it possible to use a pot core or magnetic core for the coil portion 5. Can do. In this case, in order to obtain a sufficient effect by forming the signal conductor 8 long, when the number of turns of the signal conductor 8 is n (n is a number of 2 or more, the same applies hereinafter) It is preferable that the number of turns of the electric conductor 7 is 1 or more and (n-1) or less.

  The normal mode filter elements 71 and 81 are configured by applying the configuration in which the number of turns of the signal conductor 8 is increased to the normal mode filter elements 1 and 11 by reducing the number of turns of the grounding conductor 7. However, the configuration in which the number of turns of the signal conductor 8 is increased by decreasing the number of turns of the grounding conductor 7 can also be applied to the common mode filter elements 51 and 61 described above. In this case, the number of turns of the pair of signal conductors 8a and 8b is increased while reducing the number of turns of the grounding conductor 7 and without changing the outer diameter of the coil portion. Specifically, when applied to the filter element 51, the short grounding conductor 7 and the long signal conductors 8a and 8b are connected to each other on the outermost peripheral side ends (winding end side ends). In a state where the positions are aligned, they are overlapped via the strip-shaped insulator 5b and wound so that the grounding conductor 7 is on the outside with respect to the signal conductor 8 to form a coil portion. Further, the lead portions A, B, C of the input terminal 2, the output terminal 3, and the grounding terminal 4 are set as shown in FIG. On the other hand, when applied to the filter element 61, the positions of the shortest grounding conductor 7 and the long signal conductors 8a and 8b on the innermost peripheral side end portions (winding start side end portions) are set. In an aligned state, the coil conductors are overlapped via the belt-like insulator 5b and wound so that the signal conductor 8 faces the outside of the grounding conductor 7 to form a coil portion.

  Further, in the filter elements 51 and 61, a configuration in which one grounding conductor 7 is disposed opposite to the pair of signal conductors 8a and 8b is adopted. In order to reduce the degree of capacitive coupling between the signal conductors 8a and 8b and to further improve the attenuation characteristics, the grounding conductor 7 is divided into two along the length direction and divided. A common mode filter element may be configured by causing the grounding conductor 7 to correspond to the signal conductors 8a and 8b, respectively. The present invention can also be applied to a common mode filter element having this configuration, and in the same manner as applied to each filter element 1, 11, 51, 61, in a lower frequency band of the filter element. The noise reduction effect can be greatly improved. For example, in the filter element 91 configured by applying the present invention to the filter element 51 in which the grounding conductor 7 is divided into two (grounding conductors 7a and 7b), as shown in FIG. The grounding conductors 7a and 7b and the long signal conductors 8a and 8b are overlapped via the belt-like insulator 5b in a state in which the positions of the end portions (winding end side ends) of the outermost peripheral portions are aligned. In addition, the coil portion 95 is formed by winding the signal conductors 8a and 8b so that the grounding conductors 7a and 7b are on the outside. Further, the lead-out portions A, B, and C of the input terminals 2a and 2b, the output terminals 3a and 3b, and the ground terminals 4a and 4b are set as shown in FIG. On the other hand, the filter element 101 configured by applying the present invention to the filter element 61 in which the grounding conductor 7 is divided into two (grounding conductors 7a and 7b) is short as shown in FIG. The grounding conductors 7a and 7b and the long signal conductors 8a and 8b are arranged via the belt-like insulator 5b with the positions of the end portions (winding side end portions) on the innermost peripheral side being aligned. The coil portion 105 is formed by overlapping and winding the grounding conductors 7a and 7b so that the signal conductors 8a and 8b are on the outside. Further, the lead-out portions A, B, and C of the input terminals 2a and 2b, the output terminals 3a and 3b, and the ground terminals 4a and 4b are set as shown in FIG. In addition, in said filter 91,101, about the structure same as filter element 51,61,71,81, the same code | symbol was attached | subjected and the overlapping description was abbreviate | omitted.

  Next, an Example is given and this invention is demonstrated in detail.

(Example 1, Comparative Example 1)
A grounding conductor 7 having a width of 11 mm, a pair of signal conductors 8a and 8b having a width of 3 mm, and a pair of strip insulators 5a and 5b formed of a polyimide insulating sheet having a thickness of 50 μm. In addition, a coil portion 55 having 18 turns with the grounding conductor 7 on the outer side of each signal conductor 8a, 8b is produced, and the produced coil portion 55 is used as a pot core (PC40P30 / 19Z-52H (TDK). The filter element was manufactured by mounting to a company)). In this case, a filter element in which the grounding terminal 4 is disposed on the opposite side of the input terminal 2 with the output terminal 3 interposed therebetween is produced as Example 1 for the filter element 51 described above. Further, with respect to the arrangement of the lead portions A, B, and C of the input terminal 2, the output terminal 3, and the ground terminal 4 of Example 1, the lead portion C of the ground terminal 4 is substantially the same as the lead portion A of the input terminal 2. A filter element arranged at the same position was manufactured as Comparative Example 1 for the filter element 51.

  Next, the attenuation characteristics for each frequency of the filter elements according to Example 1 and Comparative Example 1 were measured using NETWORK ANALYZER R3767CG manufactured by ADVANTEST. At this time, a method of simultaneously supplying a test signal to the signal conductors 8a and 8b by short-circuiting the pair of input terminals 2a and 2b and short-circuiting the pair of output terminals 3a and 3b was adopted. FIG. 19 shows the attenuation characteristics of the filter elements according to Example 1 and Comparative Example 1. In the drawing, the attenuation characteristic of the filter element according to the first embodiment is indicated by a symbol P, and the attenuation characteristic of the filter element according to the comparative example 1 is indicated by a symbol Q.

  According to FIG. 19, the filter element according to Comparative Example 1 cannot secure an attenuation of 30 dB or more. On the other hand, it was confirmed that the filter element according to Example 1 can secure a large attenuation amount (attenuation amount of 50 dB or more) in a frequency band of about 1.5 MHz to 15 MHz.

(Example 2, comparative example 2)
A grounding conductor 7 having a width of 11 mm, a pair of signal conductors 8a and 8b having a width of 3 mm, and a pair of strip insulators 5a and 5b formed of a polyimide insulating sheet having a thickness of 50 μm. The coil portion 65 having the number of turns 22 in which the signal conductors 8a and 8b are external to the grounding conductor 7 is produced, and the produced coil portion 65 is made into a pot core (H5C2P30 / 19Z-52H (TDK). The filter element was manufactured by mounting to a company)). In this case, a filter element in which the grounding terminal 4 is disposed on the opposite side of the input terminal 2 across the central axis O of the coil portion 65 is manufactured, and Example 2 for the filter element 61 is obtained. Further, with respect to the arrangement of the lead portions A, B, and C of the input terminal 2, the output terminal 3 and the grounding terminal 4 of the second embodiment, the lead portion C of the grounding terminal 4 is substantially the same as the lead portion A of the input terminal 2. A filter element arranged at the same position was manufactured as Comparative Example 2 for the filter element 61.

  Next, the attenuation characteristics for each frequency of the filter elements according to Example 2 and Comparative Example 2 were measured by the same method as in Example 1 and Comparative Example 1 described above. FIG. 20 shows the attenuation characteristics of the filter elements according to Example 2 and Comparative Example 2. In the figure, the attenuation characteristic of the filter element according to the second embodiment is denoted by reference symbol R, and the attenuation characteristic of the filter element according to the second comparative example is denoted by reference numeral S.

  According to FIG. 20, the filter element according to Comparative Example 2 can secure an attenuation of 50 dB or more in a frequency band near about 18 MHz, but this frequency band has a very narrow characteristic of about 1 MHz. On the other hand, it was confirmed that the filter element according to Example 2 can secure an attenuation of 50 dB or more in a wide frequency band of about 0.7 MHz to 6 MHz.

(Comparative Examples 3 and 4)
A grounding conductor 7 having a width of 11 mm, a pair of signal conductors 8a and 8b having a width of 3 mm, and a pair of strip insulators 5a and 5b formed of a polyimide insulating sheet having a thickness of 50 μm. In addition, a coil portion having 21 turns with the grounding conductor 7 being external to each of the signal conductors 8a and 8b is manufactured, and the coil portion thus prepared is a pot core (PC40P30 / 19Z-52H (manufactured by TDK). )) To prepare a filter element. In this case, as shown in FIG. 22, the output terminals 3 a, 3 b are arranged with respect to the arrangement of the lead portions A, B, C of the input terminal 2, the output terminal 3, and the ground terminal 4 of the filter element according to the first embodiment. A filter element in which the extraction portion B is disposed on the center side of the coil portion located on the opposite side to the center axis O of the coil portion was manufactured as Comparative Example 3 for the filter element 51. Further, as shown in FIG. 23, the lead portion C of the grounding terminal 4 is changed to the input terminal as compared with the arrangement of the lead portions A, B, and C of the input terminal 2, the output terminal 3 and the grounding terminal 4 of the comparative example 3. A filter element disposed at substantially the same position as the lead-out site A of No. 2 was produced and used as Comparative Example 4 for the filter element 51. In this case, the input terminal 2, the output terminal 3, and the grounding terminal 4 of Comparative Examples 3 and 4 are configured to be positioned on the plane L including the central axis O of the coil portion.

  Next, the attenuation characteristics for each frequency of the filter elements according to Comparative Examples 3 and 4 were measured by the same method as in Example 1 and Comparative Example 1 described above. Each attenuation characteristic of the filter element according to Comparative Examples 3 and 4 is shown in FIG. In the same figure, the attenuation characteristic of the filter element according to the comparative example 3 is indicated by a symbol T, and the attenuation characteristic of the filter element according to the comparative example 4 is indicated by a symbol U.

  According to FIG. 21, the filter element according to Comparative Example 3 can secure an attenuation of 50 dB or more in the frequency band of about 0.6 MHz to about 1 MHz, but the frequency band compared with Examples 1 and 2 described above. Was confirmed to have narrow characteristics. On the other hand, it was confirmed that the filter element according to Comparative Example 4 has a very narrow frequency band although it can secure an attenuation of 50 dB or more in the vicinity of about 2.3 MHz.

(Example 3, Comparative Example 5)
A pair of grounding conductors 7a and 7b having a width set to 3 mm, a pair of signal conductors 8a and 8b having a width set to 3 mm, and a pair of band-like insulators formed of a polyimide insulating sheet having a thickness of 50 μm 5a and 5b are used to produce a coil portion 95 with the grounding conductors 7a and 7b outside the signal conductors 8a and 8b, and the produced coil portion 95 is a pot core (PC40P30 / 19Z- 52H (manufactured by TDK)) to produce a filter element, which was designated as Example 3. In this case, the number of turns of the signal conductors 8a and 8b in the coil portion 95 is set to 38 by forming the grounding conductors 7a and 7b short and correspondingly forming the signal conductors 8a and 8b long. The number of turns of the grounding conductors 7a and 7b was set to 18. Further, the lead-out portions of the input terminals 2a and 2b, the output terminals 3a and 3b, and the ground terminals 4a and 4b were set to A, B, and C shown in FIG. Further, the lengths of the grounding conductors 7a and 7b and the signal conductors 8a and 8b are reduced by forming the grounding conductors 7a and 7b in the third embodiment longer and the signal conductors 8a and 8b shorter. Are prepared so that the number of turns of each of the grounding conductors 7a and 7b and the signal conductors 8a and 8b is set to be the same, and the outer diameter of the coil part is set to be the same as that of the coil part 95. Comparative Example 5 was obtained. In this case, the number of turns of the signal conductors 8a and 8b and the grounding conductors 7a and 7b were both set to 28.

  Next, the attenuation characteristics for each frequency of the filter elements according to Example 3 and Comparative Example 5 were measured using NETWORK ANALYZER R3767CG manufactured by ADVANTEST. At this time, a method of simultaneously supplying a test signal to the signal conductors 8a and 8b by short-circuiting the pair of input terminals 2a and 2b and short-circuiting the pair of output terminals 3a and 3b was adopted. FIG. 24 shows the attenuation characteristics of the filter elements according to Example 3 and Comparative Example 5. In the same figure, the attenuation characteristic of the filter element according to the third embodiment is denoted by reference character V, and the attenuation characteristic of the filter element according to the comparative example 5 is denoted by reference numeral W.

  According to FIG. 24, it was confirmed that the filter element 91 manufactured as Example 3 can improve the attenuation in the frequency band of 300 KHz to 20 MHz over the entire region as compared with the filter element manufactured as Comparative Example 5. In particular, it was confirmed that the filter element 91 manufactured as Example 3 can significantly improve the attenuation in the low frequency band of 300 KHz to 1 MHz (6 dB or more).

It is a perspective view which shows the structure of the filter element 1 (71). It is the top view which looked at filter element 1 (51, 71, 91) which shows each extraction part A, B, and C of input terminal 2, output terminal 3, and grounding terminal 4 from one end face. In order to show the configuration of the filter element 1, it is a perspective view of a state in which one end side of the strip insulators 5 a and 5 b, the grounding conductor 7 and the signal conductor 8 is unrolled. It is a perspective view which shows the structure of the filter element 11 (81). It is the top view which looked at filter element 11 (61, 81, 101) which shows each extraction part A, B, and C of input terminal 2, output terminal 3, and grounding terminal 4 from one end face. FIG. 3 is a perspective view showing a state in which one end side of the strip insulators 5a and 5b, the grounding conductor 7 and the signal conductor 8 is unrolled in order to show the configuration of the filter element 11. 3 is a perspective view showing a configuration of a filter element 21. FIG. 3 is a perspective view showing a configuration of a filter element 31. FIG. 3 is a perspective view showing a configuration of a filter element 41. FIG. 4 is a perspective view of a coil unit 5 used for the filter element 41. FIG. 3 is a perspective view showing a configuration of a filter element 51. FIG. In order to show the configuration of the filter element 51, it is a perspective view of a state in which one end side of the strip insulators 5a, 5b, the grounding conductor 7, and the signal conductors 8a, 8b are unrolled. 3 is a perspective view showing a configuration of a filter element 61. FIG. In order to show the configuration of the filter element 61, it is a perspective view of a state in which one end side of the strip insulators 5a, 5b, the grounding conductor 7, and the signal conductors 8a, 8b are unrolled. FIG. 3 is a plan view of a state in which the strip insulators 5a and 5b, the grounding conductor 7 and the signal conductor 8 constituting the filter element 71 are developed. FIG. 5 is a plan view of a state in which the strip insulators 5a and 5b, the grounding conductor 7 and the signal conductor 8 constituting the filter element 81 are developed. FIG. 3 is a plan view showing a state in which strip-shaped insulators 5a and 5b, grounding conductors 7a and 7b, and signal conductors 8a and 8b constituting the filter element 91 are developed. FIG. 2 is a plan view of a state in which strip-shaped insulators 5a and 5b, grounding conductors 7a and 7b, and signal conductors 8a and 8b constituting the filter element 101 are developed. FIG. 6 is an attenuation characteristic diagram showing the relationship between the frequency and the attenuation of the filter element according to Example 1 and Comparative Example 1. It is an attenuation characteristic figure showing the relation between the frequency of the filter element concerning Example 2 and comparative example 2, and the amount of attenuation. It is an attenuation characteristic figure showing the relation between the frequency of a filter element concerning comparative example 3 and comparative example 4, and the amount of attenuation. It is explanatory drawing 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 of the filter element which concerns on the comparative example 3. FIG. It is explanatory drawing 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 earthing | grounding of the filter element which concerns on the comparative example 4. It is an attenuation characteristic figure showing the relation between the frequency of the filter element concerning Example 3 and comparative example 5, and the amount of attenuation.

Explanation of symbols

1, 11, 21, 31, 41, 51, 61, 71, 81, 91, 101 Filter element 2 Input terminal 3 Output terminal 4 Grounding terminal 5, 15, 55, 65, 75, 85, 95, 105 Coil portion 5a, 5b Strip insulator 6 Magnetic core 7, 7a, 7b Grounding conductor 8, 8a, 8b Signaling conductor H Air gap

Claims (7)

By winding the signal strip conductor and the ground strip conductor on the signal strip conductor so that the ground strip conductor is on the outside in a state where the strip strip conductor is overlapped via the strip insulator. A coil portion formed in a cylindrical shape and having a magnetic body disposed in the center,
An input terminal connected to the outermost peripheral portion of the signal strip conductor and drawn from the outer peripheral portion of the coil portion;
An output terminal that is connected to the innermost peripheral portion of the signal strip-shaped conductor and that is led out from a central portion of the coil portion that is located on the opposite side of the lead portion of the input terminal with the magnetic material interposed therebetween;
A grounding terminal that is connected to the outermost peripheral portion of the grounding conductor for grounding and is drawn from the outer peripheral side portion of the coil portion that is located on the opposite side of the lead-out portion of the input terminal across the lead-out portion of the output terminal And a filter element. By winding the signal strip conductor and the ground strip conductor over the ground strip conductor so that the signal strip conductor is on the outside in a state where the strip strip conductor is overlapped via the strip insulator. A coil portion formed in a cylindrical shape and having a magnetic body disposed in the center,
An input terminal connected to the innermost peripheral portion of the signal strip-shaped conductor and drawn from the central portion of the coil portion;
A grounding terminal that is connected to the innermost peripheral portion of the grounding conductor for grounding and is led out from a central portion of the coil portion that is located on the opposite side of the leadout portion of the input terminal across the magnetic body;
An output terminal connected to the outermost peripheral portion of the signal strip conductor and drawn out from the outer peripheral portion of the coil portion located on the opposite side of the input portion of the input terminal across the lead portion of the grounding terminal And a filter element. Winding the pair of signal strip conductors and the ground strip conductor over the pair of signal strip conductors so that the ground strip conductor is outside the pair of signal strip conductors. A coil portion that is formed in a cylindrical shape as a whole and has a magnetic body disposed in the center,
A pair of input terminals connected to the outermost peripheral portions of the pair of signal strip conductors and drawn from the outer peripheral side portions of the coil portions;
Connected to the innermost peripheral portions of the pair of signal strip conductors and pulled out from the central portion of the coil portion located on the opposite side of the pair of input terminals from the magnetic material. A pair of output terminals,
Connected to the outermost peripheral portion of the grounding strip-like conductor and pulled out from the outer peripheral side portion of the coil portion located on the opposite side to the lead portion of the pair of input terminals across the lead portion of the pair of output terminals. And a grounding terminal. A pair of signal strip conductors and a ground strip conductor are overlapped via a strip insulator, and the pair of signal strip conductors are wound around the ground strip conductor. A coil portion that is formed in a cylindrical shape as a whole and has a magnetic body disposed in the center,
A pair of input terminals connected to the innermost peripheral portions of the pair of signal strip conductors and drawn out from the central portion of the coil portion;
A grounding terminal that is connected to the innermost peripheral portion of the grounding conductor for grounding and that is led out from a central portion of the coil portion that is located on the opposite side to the leadout portion of the pair of input terminals across the magnetic body When,
An outer peripheral portion of the coil portion connected to the outermost peripheral portions of the pair of signal strip conductors and located on the opposite side of the pair of input terminals from the lead portion of the grounding terminal. And a pair of output terminals each drawn from the filter element.   When the number of turns of the signal strip conductor is n (n is a number of 2 or more), the ground strip conductor has a number of turns of 1 to (n-1) and the outermost periphery. The filter element of Claim 1 or 3 wound in the state which aligned the edge part of the part to the edge part of the said outermost periphery part in the said strip | belt-shaped conductor for signals.   When the number of turns of the signal strip conductor is n (n is a number of 2 or more), the ground strip conductor is defined to have a winding count of 1 to (n-1) and the innermost 5. The filter element according to claim 2, wherein the filter element is wound in a state in which an end portion of the peripheral portion is aligned with an end portion of the innermost peripheral portion of the signal strip conductor.   The lead-out part of the input terminal, the lead-out part of the output terminal, and the lead-out part of the grounding terminal are located on the same plane including the central axis of the coil part. Filter element.

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