JP5300572B2 - Inductance element and noise filter using the same - Google Patents

Description

  The present invention relates to an inductance element mainly used for a noise filter or the like in an AC power supply line and a noise filter using the inductance element.

  FIG. 5 is a diagram illustrating a conventional inductance element, and is a front view partially seen through. The conventional inductance element 51 has a structure in which the outer peripheral surface of the toroidal magnetic core 52 is covered with an insulating case 53 and the windings 55 and 56 are wound around the entire surface along the circumferential direction. A copper foil 54 is provided as a foil-like conductor for capacitively coupling the windings 55 and 56 to the local portion in the insulating case 53, and a ground connection terminal 57 connected to the copper foil 54 serves as the windings 55 and 56. The lead portion is parallel to and spaced apart from the lead portion.

  By configuring in this way, the capacitance between the lines of the windings 55 and 56 is reduced, the attenuation characteristic in the high frequency region of the inductance element 51 is improved, and the band of the attenuation characteristic is widened. Is. Such an inductance element is disclosed in Patent Document 1, for example.

JP 2008-205295 A

  However, the conventional inductance element as shown in FIG. 5 has a problem that the adjustment range of the line capacitance depends on the shape of the magnetic core, so that the degree of freedom in design is limited and the line capacitance varies. It was. Further, structurally, the copper foil 54 disposed on the insulating case 53 and the ground connection terminal 57 are made of members having different shapes and forms. In particular, the ground connection terminal 57 uses a simple lead wire or the like. In many cases, each of them must be joined by soldering or the like, and the joining work is indispensable, which substantially increases the work man-hours and the manufacturing process. Also, the connection work is complicated when mounted on the power supply board.

  In order to solve the above-described problems, the present invention provides an inductance element that has a simple structure, greatly improves assembly workability and mountability, and can be reduced in price without reducing both noise control characteristics and insulation performance. And a noise filter using the same.

  In order to solve the above problems, the present invention simplifies the configuration of the inductance element without reducing the electromagnetic performance, and simplifies the arrangement work of the conductor by forming the protrusion and the groove inside the insulating case. In addition, it is possible to secure a certain insulation distance from the magnetic core, thereby suppressing variations in capacitance. In addition, mounting on the power board is greatly improved by using one end of the conductor as it is as a grounding terminal, and mounting without extending the outer dimensions by pulling out the grounding terminal from the inside of the outer periphery of the insulating case. It also makes it possible to save space.

According to the present invention, a toroidal magnetic core, an insulating case that houses the magnetic core, a coil that is formed by winding a coated conductor around the outer periphery of the insulating case, and disposed inside the insulating case, the coil And an inductance element comprising a conductor forming a capacitor via the insulating case, and a grounding terminal electrically connected to the conductor, the insulating case comprising at least a fitting portion and the step is a part, consists of two parts forming the projections on at least one of the inner walls, together with the electrically insulating the more the conductor and the magnetic core to said protrusion, said ground terminal, wherein the inside of the insulating case, an inductance element is obtained, characterized in that the draw out parallel to the central axis of the magnetic core.

  According to the present invention, an inductance element is obtained in which the conductor and the grounding terminal are made of an integral conductive material.

  According to the present invention, an inductance element is obtained in which the magnetic core has a magnetic permeability of 10,000 or more.

  According to the present invention, there is provided a noise filter in which the inductance element described above is disposed inside a metal housing having an input terminal, an output terminal, and an external grounding terminal, and both ends of the coil are connected to the input terminal and the output terminal. And a grounding terminal is connected to the external grounding terminal, whereby a noise filter is obtained.

  According to the present invention, it is possible to obtain a noise filter further including a capacitor element connected between at least one of an input terminal and an output terminal.

  According to the present invention, it is possible to obtain a noise filter characterized by further including a capacitor element connected between the external grounding terminal and each of the input terminal or the output terminal.

  According to the inductance element of the present invention, the degree of freedom in design is increased, the electromagnetic performance is improved, and further, one end of the conductor is pulled out to the outside of the insulating case as it is and is used as a grounding terminal. Since the conductor connection process by soldering etc. can be eliminated, the assembly process can be simplified and the cost can be reduced, the mounting on the power supply board can be greatly improved, and the space for mounting can be saved. It becomes possible.

  Further, if the noise filter is configured using the inductance element according to the present invention, the structure is simple, so that the number of assembling steps can be reduced, the cost can be reduced and the size can be reduced, and the magnetic core having a high permeability can be used for the inductance element. By using this, it is possible to improve the attenuation characteristics in the low frequency band.

FIG. 1A is a partially transparent plan view, FIG. 1B is a side view, and FIG. 1C is an AA cross section of FIG. 1A. FIG. 1D is an external perspective view of a conductor integrated with a grounding terminal. FIG. 2A is a partially transparent plan view, FIG. 2B is a side view, and FIG. 2C is a cross-sectional view taken along line BB in FIG. 2A. FIG. 2D is an external perspective view of a conductor integrated with a grounding terminal. 3A and 3B are diagrams illustrating a lateral inductance element according to the present invention, FIG. 3A is a partially transparent plan view, FIG. 3B is a side view, and FIG. FIG. 3D is an external perspective view of a conductor integrated with a grounding terminal. 4A and 4B are diagrams illustrating a noise filter according to the present invention, FIG. 4A is a plan transparent view, and FIG. 4B is a side transparent view. The figure explaining the conventional inductance element.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
The inductance element in the embodiment described below is for the common mode, and is configured by dividing the entire circumference of the annular magnetic core into two regions symmetrically and winding the same coil in each region. However, the present invention is not limited to this, and can be applied to an inductance element for normal mode in which only one coil is wound. Furthermore, although the inductance element in the embodiment described below is a horizontal type, it can also be applied to a vertical type.

(First embodiment)
FIG. 1 is a diagram for explaining a lateral inductance element according to the present invention. FIG. 1 (a) is a partially transparent plan view, FIG. 1 (b) is a side view, and FIG. 1 (c) is FIG. FIG. 1D is an external perspective view of a conductor integrated with a grounding terminal. In the figure, the magnetic core and the conductor integrated with the grounding terminal are indicated by hatching.

  As shown in FIG. 1, the inductance element 20a according to the present invention has a structure in which a toroidal magnetic core 1a and a headband-shaped conductor 5a made of a thin plate such as copper are arranged inside an annular insulating case 2a. It is. The conductor 5a is inserted between the protrusion 3a provided inside the insulating case 2a and the inner wall of the insulating case 2a so as to surround the outside of the magnetic core 1a. It is pulled out to the outside of the insulating case 2a through a slit (not shown) provided in a part of the mounting surface side of 2a, and its tip is used as a grounding terminal 6a. In this state, the coils 8a and 8b are formed on the outer periphery of the insulating case 2a.

In addition, protrusions 3a are formed on the inner wall of an insulating case 2a formed by fitting two upper and lower portions, so that the magnetic core 1a and the conductor 5a are not in contact with each other. The protrusion 3a may be formed so as to surround the entire outer periphery of the magnetic core. The conductor 5a and the magnetic core 1a are structurally insulated by the protrusion 3a.
Further, a step 4 is formed on the joint surface of the insulating case 2a formed by fitting the two upper and lower parts, respectively, to secure an insulating distance (creeping distance) between the inside and the outside of the insulating case.

  The magnetic core 1a has a magnetic permeability of about 10,000, which is about twice that of a general magnetic material having a magnetic permeability of about 5000. Thus, by using a high magnetic permeability material, the attenuation characteristic in the low frequency band can be improved, or the volume of the product can be reduced while maintaining the attenuation characteristic.

  The conductor 5a is obtained by processing a thin strip-like copper plate and tinning the surface to prevent corrosion. The plating may be tin, nickel, or an alloy thereof. The conductor 5a may be various conductive thin plates or foils instead of the copper plate, and may be, for example, an aluminum foil, a silver foil, a gold foil, or an alloy foil containing these metals. In addition, the conductor 5a may be arranged so as to cover not only a part of the outer peripheral surface of the magnetic core 1a but also the entire outer periphery. As long as the coils 8a and 8b and a capacitor having a sufficiently large capacity can be formed, a conductor having another shape may be used instead of the thin plate-like conductor 5a.

  Since the headband-shaped conductor 5a is arranged along the inner wall of the insulating case 2a so as to form coils 8a and 8b and a capacitor, it is more stable than the case where the magnetic core 1a is directly grounded. The obtained capacitance can be obtained, and variations in capacitance due to the clearance inside the insulating case 2a for housing the magnetic core 1a can be suppressed. Furthermore, the capacitance can be adjusted by changing the dimensions of the thin plate-like conductor 5a, and can be appropriately changed depending on the number of turns, the thickness and the length of the coils 8a and 8b, the size of the magnetic core 1a, the material characteristics, and the like. can do.

  The grounding terminal 6a is communicated in the circumferential direction and the vertical direction from an arbitrary position of the headband-shaped conductor 5a, and the outer end of the grounding terminal 6a passes through a slit (not shown) provided in a part on the mounting surface side of the insulating case 2a It is a structure drawn to Here, the inductance element 20a may be configured to ensure the positioning of the mounting terminals by using a pedestal or the like externally attached.

  The tips of the coils 8a and 8b are drawn out to the mounting surface side of the insulating case 2a as in the case of the grounding terminal 6a. However, in order to ensure the positioning of the terminals during mounting, a pedestal or the like is used. It may be a structure drawn through a through hole provided in the pedestal.

  Thus, by using the inductance element 20a having a structure for grounding the grounding terminal 6a, it is possible to obtain a good attenuation characteristic over a relatively wide frequency range without deterioration of the attenuation characteristic even in a high frequency band. it can.

(Second Embodiment)
2A and 2B are diagrams illustrating a lateral inductance element according to the present invention. FIG. 2A is a partially transparent plan view, FIG. 2B is a side view, and FIG. 2C is FIG. 2A. FIG. 2D is an external perspective view of the conductor integrated with the grounding terminal. In the figure, the magnetic core and the conductor integrated with the grounding terminal are indicated by hatching.

  As shown in FIG. 2, the inductance element 20 b of the present invention is the same as the horizontal inductance element 20 a shown in the first embodiment described above, but the external shape of the conductor 5 b is changed and the arrangement position thereof is changed. In the example, it is a structure that has a donut shape and is disposed on the mounting surface side of the magnetic core.

  The inductance element 20b has a structure in which a toroidal magnetic core 1b and a donut-shaped conductor 5b made of a thin plate such as copper are arranged inside an annular insulating case 2b. The conductor 5b is arranged on the mounting surface side of the magnetic core 1b, and is inserted between the protrusion 3b provided inside the insulating case 2b and the inner wall of the insulating case 2b so as to insulate from an arbitrary position of the conductor 5b. It is pulled out to the outside of the insulating case 2b through a slit (not shown) provided in a part on the mounting surface side of the case 2b, and its tip is used as a grounding terminal 6b. In this state, the coils 8a and 8b are formed on the outer periphery of the insulating case 2a.

In addition, protrusions 3b are formed on the inner wall of the insulating case 2b formed by fitting the two upper and lower parts, so that the magnetic core 1b and the conductor 5b are not in contact with each other. The protrusion 3b may be formed so as to surround the entire outer periphery of the magnetic core 1b. The conductor 5b and the magnetic core 1b are structurally insulated by the protrusion 3b.
Furthermore, a step 4 is formed on each joint surface of the insulating case 2b formed by fitting the two upper and lower portions, thereby ensuring an insulation distance (creeping distance) between the inside and the outside of the insulating case.

(Third embodiment)
3A and 3B are diagrams for explaining a lateral inductance element according to the present invention. FIG. 3A is a partially transparent plan view, FIG. 3B is a side view, and FIG. 3C is FIG. FIG. 3D is an external perspective view of the conductor integrated with the grounding terminal. In the figure, the magnetic core and the conductor integrated with the grounding terminal are indicated by hatching.

  As shown in FIG. 3, the inductance element 20c of the present invention has a structure in which the first embodiment and the second embodiment described above are combined.

  The inductance element 20c is formed from a toroidal magnetic core 1c, two bowl-shaped conductors 5c1 and 5c2 made of a thin plate such as copper, and a thin plate such as copper inside the annular insulating case 2c. The toroidal conductor 5c3 is arranged. The headband-shaped conductor 5c1 is disposed inside the magnetic core 1c, the headband-shaped conductor 5c2 is disposed so as to surround the outside of the magnetic core 1c, and the donut-shaped conductor 5c3 is mounted on the mounting surface of the magnetic core 1c. The mounting surface of the insulating case 2c is arranged from any position of each of the conductors 5c1, 5c2, 5c3 by being inserted between the protrusion 3c provided inside the insulating case 2c and the inner wall of the insulating case 2c. It is pulled out to the outside of the insulating case 2c through a slit (not shown) provided in a part of the side, and the tip portions thereof are ground terminals 6c1, 6c2, and 6c3, respectively. In this state, the coils 8a and 8b are formed on the outer periphery of the insulating case 2c.

In addition, the protrusion 3c formed on the inner wall of the insulating case 2c formed by fitting the two upper and lower parts is formed so that the magnetic core 1c and the conductors 5c1, 5c2, 5c3 are not in contact with each other. Alternatively, it may be formed in a scattered manner or may be formed so as to surround the entire outer periphery of the magnetic core. The conductors 5c1, 5c2, 5c3 and the magnetic core 1c are structurally insulated by the protrusion 3c.
Further, a step 4 is formed on the joint surface of the insulating case 2c formed by fitting the two upper and lower parts, respectively, to secure an insulating distance (creeping distance) between the inside and the outside of the insulating case.

(Fourth embodiment)
4A and 4B are diagrams for explaining a noise filter according to the present invention. FIG. 4A shows a plan transparent view, and FIG. 4B shows a side transparent view.

  In general, a noise filter is not only an inductance element but also a capacitor element (hereinafter referred to as “X-con”) for removing normal mode noise generated between input lines, and generated between the input line and another potential. Although there is an element including a capacitor element (hereinafter referred to as “Y-con”) for removing common mode noise, a case where only an X-con is provided will be described.

  As shown in FIG. 4, the noise filter 30 according to the present invention is a noise filter that includes the horizontal inductance element 20 a according to the first embodiment described above and an X-con 32 and is covered with a metal casing 31. .

  The metal casing 31 includes a commercial power input socket 36 having input terminals 33 and 34 and a ground terminal 35, output terminals 37 and 38, and an external grounding terminal 39. Both ends of the coil 8b of the inductance element 20a are electrically connected to the input terminal 33 and the output terminal 37, respectively, and both ends of the coil 8a are electrically connected to the input terminal 34 and the output terminal 38, respectively. Further, the ground terminal 6 a is electrically connected to the ground terminal 35. The two terminals of the X-con 32 are electrically connected to the input terminal 33 and the input terminal 34, respectively.

  Further, as shown in FIG. 4B, the ground terminal 35 is electrically connected to the metal casing 31, and the metal casing 31 is grounded via the external grounding terminal 39.

The noise filter 30 described above does not include a Y-con, but it may have a configuration in which a Y-con is further provided between the output terminals 37 and 38 and the metal casing 31, and only the Y-con is used instead of the X-con. It is good also as a structure provided. Further, the X capacitor may be connected to the output terminal side. Further, one or more of these X-con and Y-con may be provided.
Y-con has the characteristic of removing common mode noise. On the other hand, it is desirable that Y-con is appropriately selected according to the required characteristics because it also leaks a signal that is originally required.

  In any of the cases described above, the specific characteristics of the inductance element can be adjusted by adjusting the area where the conductor and coil face each other and the material and thickness of the intervening insulating case, and the capacitance of the capacitor element. By adjusting this, it is possible to adjust the attenuation characteristic as a noise filter.

The magnetic cores 1a, 1b, and 1c may be any material as long as the material is a magnetic material having a high magnetic permeability, such as Mn—Zn based or Ni—Zn based ferrite materials, amorphous or permalloy metal based materials, iron based It may be a powder material made of a conductive material such as an iron alloy or other metal powder, and is preferably selected as appropriate according to required characteristics. By using a material with high magnetic permeability, the attenuation characteristics in the low frequency band can be improved as noise characteristics, or the volume of the product can be reduced while maintaining the attenuation characteristics as it is. A material having a magnetic permeability of 10,000 or more is preferably used.
Further, the outer shape may be any shape such as a circle, an ellipse, and a rectangle, and the cross-sectional shape may be any shape such as a circle, an ellipse, an oval, and a polygon.

The insulating cases 2a, 2b, and 2c may be made of any material as long as it is a resin material that covers the magnetic core 1 in an insulating manner, such as an epoxy-based or phenol-based thermosetting resin, polypropylene (PP), polystyrene (PS), or polybutylene. Either terephthalate (PBT) or nylon thermoplastic resin may be used. Moreover, you may have a partition part which divides | segments the center space part of a cyclic | annular insulation case into plurality.
The insulating case is provided with a slit (hole) for drawing out the conductor to the outside of the insulating case.

  The protrusions 3a, 3b, and 3c may be formed on the inner wall of the insulating case so that the magnetic core and the conductor are not in direct contact with each other. You may install so that the whole outer periphery of may be covered. The inner wall of the insulating case that is the installation location may be at least part of the outer diameter side, inner diameter side, upper surface side, and bottom surface (mounting surface) side of the magnetic core. It is also preferable to adjust the thickness as appropriate in consideration of the line capacity. Furthermore, it is good also as a groove part instead of a projection part.

  The step 4 may be formed on a part or the whole of the joint surface of the insulating case formed by fitting the two parts, but is preferably the whole surface from the viewpoint of the insulation distance (creeping distance). In addition, the cross-sectional shape may be any of a substantially Z shape or an uneven shape.

The conductor 5a, 5b, 5c1, 5c2, 5c3 may be any material as long as it has conductivity, such as metal materials such as copper, aluminum, stainless steel, and brass, alloys thereof, metal material powder and resin. Any of a metal resin mixed with may be used.
The outer shape of the conductor is a plate shape, foil shape, strip shape, or the like, which has a so-called headband shape or donut shape in which both ends are coupled and short-circuited (short-circuited), but both ends are not coupled and short-circuited (short-circuited). It is good also as what is called a C-shape. Further, the conductors may be disposed at least a part on the outer diameter side, the inner diameter side, the upper surface side, and the bottom surface (mounting surface) side of the magnetic core. It is necessary to avoid contact with each other. This is to prevent generation of eddy current due to magnetic flux. In addition, since a capacity | capacitance characteristic will become large if it arrange | positions a conductor to the perimeter part of a magnetic core, it is preferable to set suitably according to a required characteristic.

  The grounding terminals 6a, 6b, 6c1, 6c2, and 6c3 may have any structure that can be easily pulled out to the outside of the insulating case. Space can be achieved. Further, when pulling out one end of the conductor to the outside of the insulating case, it may be arranged so as not to be in direct contact with the coils 8a and 8b, and it is preferable to design appropriately according to the requirements of the insulation distance based on various safety standards.

  The coils 8a and 8b may be made of any conductive wire such as enameled copper wire with a natural resin or synthetic resin paint baked on the conductor, or a PVC coated electric wire with improved insulation. The cross-sectional shape of the conducting wire may be any of a circle, an ellipse, an oval, a rectangle, and the like. Furthermore, it is preferable that the wire diameter, the number of turns, and the number of the coils 8a and 8b are appropriately designed and adjusted according to required characteristics.

  As the X capacitor 32 and the Y capacitor (not shown), any type of capacitor such as electrolysis, film, or multilayer ceramic may be used.

Hereinafter, it explains in full detail using an Example.
Of the above embodiments, an example of the noise filter in the fourth embodiment shown in FIG. 4 will be described in detail.

  First, the horizontal inductance element 20a according to the first embodiment shown in FIG. 1 was used as the inductance element.

As the magnetic core 1a, a Ni—Zn ferrite material was used, and the shape was a toroidal shape with an outer diameter of 22 mm, an inner diameter of 14 mm, and a height of 10 mm.
As the insulating case 2a, a molded body made of PBT resin and having an outer diameter of φ27 mm, an inner diameter of φ9 mm, a height of 18 mm, and a wall thickness of 0.9 mm was used to house the magnetic core 1a.
Inside the insulating case 2a, projections 3a having a thickness of 1 mm, a height of 3 mm, and a width of 3 mm are provided on the outer periphery of the magnetic core 1a, and a gap between the inner wall of the insulation case 2a and the projection 3a is 1 mm. It was. As a conductor 5a, a copper plate having a thickness of 0.3 mm is 7 mm wide and 78 mm long, and protrudes in a T-shape from the center in the length direction in a direction perpendicular to the length direction. It cut out to the shape used as the terminal 6a, and also soldered the both ends of the length direction.
As the coils 8a and 8b, polyester coated copper wires (PEW wires) with a wire diameter of φ0.6 mm were used, and the semicircular portions of the outer peripheral portion of the insulating case 2a were respectively symmetrically wound with 44 turns each. .

  As the X-con 32, a film capacitor having a capacity of 0.47 pF, a length of 10 mm, a width of 16 mm, and a height of 16 mm was prepared.

  As the metal casing 31, a commercial power input socket 36 having input terminals 33, 34 and a ground terminal 35 in an aluminum box having a length of 60 mm, a width of 33 mm, and a height of 23 mm, output terminals 37, 38, and an external grounding terminal 39 are provided. We prepared for each one.

  Both ends of the coil 8b are respectively connected to the input terminal 33 and the output terminal 37, both ends of the coil 8a are respectively connected to the input terminal 34 and the output terminal 38, the ground terminal 6b is connected to the ground terminal 35, and the two terminals of the X-con 32 are connected. The noise filter 30 of the present invention shown in FIG. 6 was obtained by connecting to the input terminal 33 and the input terminal 34 by soldering.

(Comparative example)
As a comparative example, a conventional inductance element 51 shown in FIG. 5 and a noise filter using the same were prepared using the same members as in the above-described embodiment and provided with a grounding terminal using a lead wire.

  Attenuation characteristics were measured for each of the noise filters of Examples and Comparative Examples produced according to the above procedure, and further, processing and assembly workability was confirmed for each of the inductance elements of Examples and Comparative Examples.

  As a result of the confirmation, almost the same characteristics were obtained in the attenuation characteristics of the noise filters of the example and the comparative example, and the difference was not seen. Compared to the comparative example, the working example of the conductor is easier in the embodiment, and the soldering work of the conductor and the grounding terminal is no longer necessary. Further, it has been found that there is a significant cost reduction effect. Further, it was found that when the inductance element is mounted on the power supply board, it can be mounted as it is, so that the board mounting property at the customer is greatly improved.

  As described above, only the noise filter 30 using the inductance element 20a according to the first embodiment has been described as the form of the noise filter of the present invention. Similarly, the inductance according to the second embodiment and the third embodiment is described. A noise filter using the elements 20b and 20c can also be configured. In that case, the connection method of the coils 8a and 8b, the ground terminals 6b, 6c1, 6c2, 6c3, the housing, etc. may be changed as appropriate. . Further, in place of the magnetic element having the toroidal shape such as the inductance element according to the first to third embodiments, the magnetic core such as EI type and EE type that is used and mounted when an insulating bobbin is used. It is also possible to use an inductance element having a structure in which a coil is wound around an insulating bobbin.

  The embodiments of the present invention have been described above using the embodiments. However, the present invention is not limited to these embodiments, and the present invention is not limited to the scope of the present invention. Included in the invention. That is, various changes and modifications that can be naturally made by those skilled in the art are also included in the present invention.

  With the inductance element of the present invention, not only high performance (wideband) of noise filters mounted on various electronic devices, but also miniaturization, cost reduction, and further improvement in workability and mountability can be achieved in the EMC and EMI markets. It can also contribute to technology construction.

1a, 1b, 1c Magnetic core 2a, 2b, 2c Insulating case 3a, 3b, 3c Protrusion 4 Step 5a, 5b, 5c1, 5c2, 5c3 Conductor 6a, 6b, 6c1, 6c2, 6c3 Grounding terminal 8a, 8b Coil
20a, 20b, 20c Inductance element 30 Noise filter 31 Metal housing 32 X-con 33, 34 Input terminal 35 Ground terminal 36 Commercial power input sockets 37, 38 Output terminal 39 External ground terminal 51 Inductance element 52 Magnetic core 53 Insulation Case 54 Copper foil 55, 56 Winding 57 Ground connection terminal

Claims (6)

A toroidal-shaped magnetic core; an insulating case that houses the magnetic core; a coil formed by winding a coated conductor around the outer periphery of the insulating case; An inductance element comprising a conductor forming a capacitor through a case and a grounding terminal electrically connected to the conductor, wherein the insulating case has a step in at least a part of the fitting portion. consists of two parts forming the projections on at least one of the inner walls, together with the electrically insulates more the magnetic core and the conductor in the protrusion, the ground terminal, from the inside of the insulating case , the inductance element, characterized in that the draw out parallel to the central axis of the magnetic core.   The inductance element according to claim 1, wherein the conductor and the grounding terminal are made of an integral conductive material.   The inductance element according to claim 1, wherein the magnetic core has a magnetic permeability of 10,000 or more.   A noise filter in which the inductance element according to any one of claims 1 to 3 is disposed inside a metal housing having an input terminal, an output terminal, and an external grounding terminal, wherein both ends of the coil are connected to the end of the coil. A noise filter, wherein the noise filter is connected to an input terminal and an output terminal, and the grounding terminal is connected to the external grounding terminal.   The noise filter according to claim 4, further comprising a capacitor element connected between at least one of the input terminal and the output terminal.   The noise filter according to claim 4, further comprising a capacitor element connected between the external grounding terminal and each of the input terminal or the output terminal.

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