Noise filter

Abstract

The present invention reduces the size of a coil body part in the axial direction.　A noise filter (1) comprises: a first edgewise coil (21A) having a spiral first coil part (22A); and a second edgewise coil (21B) having a spiral second coil part (22B). The first coil part (22A) and the second coil part (22B) make up a coil body part (22) formed of a single flat wire (30) alone. The second coil part (22B) is disposed so as to surround the first coil part (22A), and is disposed in the same region as the first coil part (22A) in the axial direction.

Description

Noise Filter

[0001] The present disclosure relates to noise filters.

[0002] Patent Document 1 discloses a noise filter having a coil member made of an insulated electric wire. The insulated electric wire is spirally wound so as to be aligned in the axial direction of the coil member.

[0003] Japanese Patent Application Laid-Open No. 2016-076565

[0004] The noise reduction function of the above noise filter can be improved by increasing the number of turns of the coil member, but increasing the number of turns of the coil member increases the axial dimension of the coil member, which is a problem.

[0005] The noise filter of the present disclosure was completed based on the above circumstances, and aims to reduce the size of the coil body in the axial direction.

[0006] The noise filter of the present disclosure comprises a first edgewise coil having a spiral first coil portion, and a second edgewise coil having a spiral second coil portion, wherein the first coil portion and the second coil portion form a coil main body portion made of only a single flat wire, and the second coil portion is arranged so as to surround the first coil portion and is arranged in a region common to the first coil portion in the axial direction.

[0007] According to the present disclosure, it is possible to reduce the size of the coil main body in the axial direction.

[0008] FIG. 1 is a perspective view of a noise filter of Example 1. FIG. 2 is a plan view of the noise filter. FIG. 3 is a front view of the noise filter. FIG. 4 is a left side view of the noise filter. FIG. 5 is a cross-sectional view taken along line XX in FIG. 2. FIG. 6 is a cross-sectional view taken along line YY in FIG. 3.

[0009] [Description of Embodiments of the Present Disclosure] First, embodiments of the present disclosure will be listed and described. Any combination of the following multiple embodiments without causing any contradiction is also included in the embodiments for carrying out the invention. The noise filter of the present disclosure includes: (1) a first edgewise coil having a spiral first coil portion, and a second edgewise coil having a spiral second coil portion, the first coil portion and the second coil portion constituting a coil main body portion made only of a single rectangular wire, the second coil portion being disposed so as to surround the first coil portion and being disposed in a region common to the first coil portion in the axial direction.

[0010] In the present disclosure, the first coil portion and the second coil portion are each made of a single rectangular wire and form a single coil body. The second coil portion is arranged to surround the first coil portion, and the first coil portion and the second coil portion are arranged in a common axial area. Therefore, the axial dimension of the coil body can be reduced compared to a coil made by spirally winding a rectangular wire with a constant circumferential length. According to the present disclosure, the axial size of the coil body can be reduced.

[0011] (2) In (1), the flat wire preferably has a folded portion and a pair of extending portions extending parallel to each other adjacent to each other from the folded portion, the pair of extending portions constituting the first coil portion and the second coil portion, the first edgewise coil having a first connection terminal connected to an end of one of the extending portions and protruding from the first coil portion, the second edgewise coil having a second connection terminal connected to an end of the other of the extending portions and protruding from the second coil portion, the first connection terminal and the second connection terminal being located at one end of the first coil portion and the second coil portion in the axial direction. With this configuration, the first connection terminal and the second connection terminal are connected to a pair of extending portions extending parallel to each other adjacent to each other from the folded portion, thereby realizing the first connection terminal and the second connection terminal being located at one end of the first coil portion and the second coil portion in the axial direction.

[0012] (3) In (2), it is preferable that the first connection terminal portion and the second connection terminal portion are arranged at positions that are rotationally symmetric when the first coil portion and the second coil portion are viewed in the axial direction. With this configuration, the first connection terminal portion and the second connection terminal portion can be arranged at predetermined positions without considering the circumferential orientation of the first edgewise coil and the second edgewise coil.

[0013] (4) In (1) to (3), it is preferable that the first coil portion is disposed radially inward and the second coil portion is disposed radially outward. With this configuration, the axial dimensions of the first coil portion and the second coil portion can be kept small.

[0014] (5) In (2) or (3), it is preferable that the first connection terminal abuts against the second coil portion in the axial direction, and the second connection terminal abuts against the first coil portion in the axial direction. Because the thickness direction of the flat wire in the first coil portion and the second coil portion is oriented in the axial direction, they can elastically deform individually to expand in the axial direction. If the first coil portion and the second coil portion elastically deform in different ways, there is a concern that the magnetic field may become unstable. To address this issue, the first connection terminal abuts against the second coil portion in the axial direction, and the second connection terminal abuts against the first coil portion in the axial direction. This configuration prevents the first coil portion and the second coil portion from elastically deforming in different ways, thereby avoiding magnetic field instability.

[0015] (6) In (2) or (3), it is preferable that the pair of extending portions includes a first extending portion constituting the first coil portion and a second extending portion constituting the second coil portion, and the first extending portion and the second extending portion are alternately arranged in the axial direction of the first coil portion and the second coil portion. With this configuration, it is possible to reduce the projected areas of the first coil portion and the second coil portion when viewed in the axial direction of the first coil portion and the second coil portion.

[0016] [Details of the Embodiments of the Present Disclosure] [Example 1] A noise filter 1 according to Example 1 embodying the present disclosure will be described with reference to FIGS. 1 to 6. The present invention is not limited to these examples, but is defined by the claims, and includes all modifications within the meaning and scope of the claims. In Example 1, the F direction in FIGS. 1, 2, 4, and 6 is defined as the front. The H direction in FIGS. 1, 3 to 5 is defined as the up. The L direction in FIGS. 1 to 3, 5, and 6 is defined as the left. The up and down direction and the axial direction are used interchangeably.

[0017] The noise filter 1 of the first embodiment is configured to include one core 10 and one edgewise coil 20. The core 10 is a member made of a magnetic substance such as iron or a member containing a magnetic material. The core 10 has a prismatic shaft portion 11 and upper and lower flange portions 12 and 13 formed on both axial ends of the shaft portion 11. The core 10 is used with its axis oriented in the vertical direction.

[0018] In an axial view (plan view) of the core 10 viewed in the axial direction of the shaft portion 11, the shaft portion 11, the upper flange portion 12, and the lower flange portion 13 form a square. The centers of the upper flange portion 12 and the lower flange portion 13 when viewed in the axial direction coincide with the center of the shaft portion 11. The length of one side of the lower flange portion 13 is greater than the length of one side of the upper flange portion 12. Four protrusions 14 are formed on the lower surface of the upper flange portion 12 (the surface facing the lower flange portion 13). The four protrusions 14 are located at the center positions of each side of the upper flange portion 12 in the longitudinal direction.

[0019] The edgewise coil 20 is a single component formed by bending a single rectangular wire 30. The cross-sectional shape of the rectangular wire 30 is a rectangular wire with a relatively large ratio of long sides to short sides. The rectangular wire 30 is arranged with the short side (thickness direction) of the cross-sectional shape facing the axial direction (vertical direction). The rectangular wire 30 is a component in which a conductor made of a conductive material such as copper, aluminum, or carbon nanotubes is surrounded by an insulating coating. As shown in FIG. 6 , the rectangular wire 30 has a folded portion 33, a first extending portion 31 extending from the folded portion 33, and a second extending portion 32 extending from the folded portion 33. The first extending portion 31 and the second extending portion 32 are bent to form a square when viewed in the axial direction.

[0020] The edgewise coil 20 is composed of a first edgewise coil 21A and a second edgewise coil 21B. The first edgewise coil 21A has a first coil portion 22A and a first connection terminal portion 27A. The second edgewise coil 21B has a second coil portion 22B and a second connection terminal portion 27B. The first coil portion 22A and the second coil portion 22B form a coil main body 22. When viewed in the axial direction, the coil main body 22 (the first coil portion 22A and the second coil portion 22B) has a square shape as a whole.

[0021] The coil main body 22 is disposed so as to surround the shaft portion 11 when viewed in the axial direction. When viewed in the axial direction, the first coil portion 22A is located radially inward, and the second coil portion 22B is located radially outward. The first coil portion 22A is disposed coaxially with the shaft portion 11, with its inner circumferential surface directly adjacent to and facing the outer circumferential surface of the shaft portion 11. The second coil portion 22B is disposed coaxially with the shaft portion 11 and the first coil portion 22A, with its inner circumferential surface directly adjacent to and facing the outer circumferential surface of the first coil portion 22A. The coil main body 22 is placed on the upper surface of the lower flange portion 13. When viewed from the front of the noise filter 1, the coil main body 22 is disposed so as to be sandwiched between the upper flange portion 12 and the lower flange portion 13.

[0022] The first coil portion 22A is a portion of the first extension portion 31 formed into a spiral shape so as to form a square when viewed in the axial direction. The first coil portion 22A has a first front edge portion 23A, a first rear edge portion 24A, a first right edge portion 25A, and a first left edge portion 26A. The second coil portion 22B is a portion of the second extension portion 32 formed into a spiral shape so as to form a square when viewed in the axial direction. When viewed in the axial direction, the second coil portion 22B has a second front edge portion 23B, a second rear edge portion 24B, a second right edge portion 25B, and a second left edge portion 26B.

[0023] 6, the front end of the first extending portion 31 located at the bottom of the first left edge 26A is defined as the first base end 28A. The front end of the second extending portion 32 located at the bottom of the second left edge 26B is defined as the second base end 28B. The folded portion 33 of the rectangular wire 30 is a portion at the bottom of the coil main body 22 where the first base end 28A and the second base end 28B are connected in a U-turn shape.

[0024] The first extending portion 31 extends spirally from the first base end 28A through the first left edge 26A, the first rear edge 24A, the first right edge 25A, the first front edge 23A, and back to the first left edge 26A, thereby constituting the first coil portion 22A. The second extending portion 32 extends spirally from the second base end 28B through the second left edge 26B, the second rear edge 24B, the second right edge 25B, the second front edge 23B, and back to the second left edge 26B, thereby constituting the second coil portion 22B. The first extending portion 31 and the second extending portion 32 extend from the folded portion 33 parallel to each other and adjacent to each other in the long side direction of the cross section of the rectangular wire 30, thereby constituting a single deemed flat wire 35. The assumed wire 35 extends from the folded portion 33 in a spiral shape so as to form a square along the outer circumferential surface of the shaft portion 11, thereby constituting the coil main body 22. The assumed wire 35 (the first coil portion 22A and the second coil portion 22B) has a flattened shape, and is therefore capable of elastic deformation in a form that expands in the axial direction.

[0025] The portions of the first extending portion 31 that form the first rear edge 24A, the first right edge 25A, and the first left edge 26A are arranged horizontally in a front view and in a side view of the noise filter 1. The portion of the first extending portion 31 that forms the first front edge 23A is inclined upward from the right end toward the left end in a front view. The portion of the first extending portion 31 that forms the first front edge 23A is arranged to connect the front end of the right edge to the front end of the first left edge 26A, which is one step higher than the right edge.

[0026] The square region on the inner periphery of the first coil portion 22A is positioned so as to be recessed under the upper flange portion 12. The protrusions 14 of the upper flange portion 12 press against the upper surfaces of the first left edge portion 26A and the first rear edge portion 24A of the topmost section of the first coil portion 22A. The first coil portion 22A is sandwiched in the vertical direction between the lower flange portion 13 and the upper flange portion 12 by the pressure of the protrusions 14. Therefore, the first coil portion 22A is held in a state in which its movement relative to the core 10 in the vertical direction (axial direction) is restricted.

[0027] The first connection terminal 27A is continuous with the extending end of the first extending portion 31. The first connection terminal 27A is a portion that extends rightward from the extending end of the first extending portion 31 at the right end (extending end) of the uppermost stage of the first rear edge 24A of the first coil portion 22A. When viewed in the axial direction, the first connection terminal 27A extends rightward without bending the right end portion of the first rear edge 24A.

[0028] The portion of the first connection terminal 27A that protrudes to the right of the upper flange 12 is bent so as to ride on the uppermost end surface of the second right edge 25B in a front view and is disposed so as to abut against or face closely to the rear end of the uppermost end surface of the second right edge 25B from above, thereby preventing the second coil 22B from moving upward relative to the first coil 22A.

[0029] The portions of the second extending portion 32 that form the second rear edge 24B, the second right edge 25B, and the second left edge 26B are horizontally disposed in front and side views. The portion of the second extending portion 32 that forms the second front edge 23B is inclined upward from the right end toward the left end in front view. The portion of the second extending portion 32 that forms the second front edge 23B is disposed so as to connect the front end of the second right edge 25B to the front end of the second left edge 26B, which is one step higher than the second right edge 25B. The inclination angle of the portion of the second extending portion 32 that forms the second front edge 23B on the acute angle side relative to the horizontal direction (left-right direction) is smaller than the inclination angle of the portion of the first extending portion 31 that forms the first front edge 23A on the acute angle side relative to the horizontal direction.

[0030] The second connection terminal 27B is continuous with the extending end of the second extending portion 32. The second connection terminal 27B is a portion of the second coil portion 22B that extends from the extending end of the second extending portion 32 at the left end (extending end) of the uppermost stage of the second rear edge portion 24B. When viewed in the axial direction, the second connection terminal 27B bends from the left end of the second front edge portion 23B to extend rearward along the left edge of the upper flange portion 12, and then bends leftward from the rear end of the extending portion to extend away from the upper flange portion 12. The portion of the second connection terminal 27B along the left edge of the upper flange portion 12 is positioned to abut against or closely face the uppermost end surface of the first left edge portion 26A from above. Therefore, there is no risk of the first coil portion 22A moving upward relative to the second coil portion 22B.

[0031] The first connection terminal 27A and the second connection terminal 27B are arranged at one end (upper end) in the axial direction of the core 10 and the edgewise coil 20. When viewed in the axial direction, the first connection terminal 27A and the second connection terminal 27B have a rotationally symmetrical positional relationship. A communication circuit (not shown) that is the target of noise suppression by the noise filter 1 is connected to the first connection terminal 27A and the second connection terminal 27B. One of the first connection terminal 27A and the second connection terminal 27B functions as an input terminal, and the other functions as an output terminal.

[0032] The noise filter 1 of the first embodiment includes a first edgewise coil 21A having a spiral first coil portion 22A and a second edgewise coil 21B having a spiral second coil portion 22B. The first coil portion 22A and the second coil portion 22B form a coil main body 22 made of only a single rectangular wire 30. The second coil portion 22B is disposed so as to surround the first coil portion 22A and is disposed in a region common to the first coil portion 22A in the axial direction.

[0033] In the first embodiment, the first coil portion 22A and the second coil portion 22B are each made of a single rectangular wire 30 and form a single coil body 22. The second coil portion 22B is arranged to surround the first coil portion 22A. The first coil portion 22A and the second coil portion 22B are arranged within a common axial area (within a certain height range). Therefore, compared to a coil made of a rectangular wire wound spirally with a constant circumferential length, the axial (height) dimension of the coil body 22 is kept small, achieving a low profile. The noise filter 1 of the first embodiment can improve noise reduction performance without increasing the axial size of the coil body 22.

[0034] Since one assumed wire 35 has a divided structure consisting of two extending portions (first extending portion 31 and second extending portion 32), the process of forming the assumed wire 35 into a spiral can be performed on each extending portion individually (first extending portion 31 and second extending portion 32 separately). The cross-sectional area of ​​the first extending portion 31 is smaller than that of one assumed wire 35. The cross-sectional area of ​​the second extending portion 32 is smaller than that of one assumed wire 35. Therefore, compared to bending one rectangular wire having the same cross-sectional area as one assumed wire 35 into a spiral, the noise filter 1 of this embodiment 1 has an easier process of bending the flat wire 30 (first extending portion 31 and second extending portion 32) into a spiral.

[0035] The rectangular wire 30 has a folded portion 33 and a pair of extending portions (first extending portion 31 and second extending portion 32) extending from the folded portion 33 in a parallel and adjacent relationship. The first extending portion 31 constitutes the first coil portion 22A, and the second extending portion 32 constitutes the second coil portion 22B. The first edgewise coil 21A is connected to the extending end of the first extending portion 31 and has a first connection terminal 27A protruding from the first coil portion 22A. The second edgewise coil 21B is connected to the extending end of the second extending portion 32 and has a second connection terminal 27B protruding from the second coil portion 22B. The first connection terminal 27A and the second connection terminal 27B are connected to the pair of extending portions (first extending portion 31 and second extending portion 32) extending from the folded portion 33 in a parallel and adjacent relationship. This configuration makes it possible to position the first connection terminal portion 27A and the second connection terminal portion 27B at one end (upper end) in the axial direction (vertical direction) of the coil main body portion 22 (first coil portion 22A and second coil portion 22B).

[0036] The first connection terminal 27A and the second connection terminal 27B are arranged at positions that are rotationally symmetric when viewed in the axial direction of the coil main body 22 (the first coil portion 22A and the second coil portion 22B). With this configuration, the first connection terminal 27A and the second connection terminal 27B can be arranged at predetermined positions without considering the circumferential orientation of the first edgewise coil 21A and the second edgewise coil 21B.

[0037] The first coil portion 22A is disposed radially inside the coil main body 22. The second coil portion 22B is disposed radially outside the coil main body 22. With this configuration, the axial (vertical) dimension of the coil main body 22 (the first coil portion 22A and the second coil portion 22B) can be kept small.

[0038] Because the thickness direction of the flat wire 30 (first extension 31 and second extension 32) is oriented in the axial direction, the first coil portion 22A and the second coil portion 22B can elastically deform independently, stretching in the axial direction. If the first coil portion 22A and the second coil portion 22B elastically deform in different ways, there is a concern that the magnetic field may become unstable. To address this issue, the first connection terminal portion 27A abuts against the uppermost end of the second coil portion 22B from above in the axial direction, and the second connection terminal portion 27B abuts against the uppermost end of the first coil portion 22A from above in the axial direction. This configuration prevents the first coil portion 22A and the second coil portion 22B from elastically deforming in different ways, thereby avoiding magnetic field instability.

[0039] [Other Examples] The present invention is not limited to the examples described above and illustrated in the drawings, but is defined by the claims. The present invention includes the meaning equivalent to the claims and all modifications within the scope of the claims, including the following embodiments.

[0040] The shapes of the outer peripheral surface of the shaft portion, the first coil portion, and the second coil portion are not limited to a square, and may be polygonal, trapezoidal, circular, or curved. The first connection terminal portion and the second connection terminal portion may be arranged in positions other than rotational symmetry. The noise filter may not have a core. The first connection terminal portion may have a curved shape when viewed in the axial direction. The first edgewise coil and the second edgewise coil may be displaceable relative to the core in the axial direction. The upper flange portion may be sized to overlap the entire first coil portion, the inner peripheral region of the second coil portion, or the entire second coil portion when viewed in the axial direction. A flange portion may be provided at the upper end of the shaft portion of the core to restrict relative axial displacement of the first coil portion and the second coil portion.

[0041] REFERENCE SIGNS LIST 1...Noise filter 10...Core 11...Shaft portion 12...Upper flange portion 13...Lower flange portion 14...Protrusion portion 20...Edgewise coil 21A...First edgewise coil 21B...Second edgewise coil 22...Coil main body portion 22A...First coil portion 22B...Second coil portion 23A...First front edge portion 23B...Second front edge portion 24A...First rear edge portion 24B...Second rear edge portion 25A...First right edge portion 25B...Second right edge portion 26A...First left edge portion 26B...Second left edge portion 27A...First connection terminal portion 27B...Second connection terminal portion 28A...First base end portion 28B...Second base end portion 30...Rectangular wire 31...First extension portion (extension portion, one extension portion) 32... Second extending portion (extending portion, other extending portion) 33... Turned-back portion 35... Deemed wire

Claims

1. A noise filter comprising a first edgewise coil having a spiral first coil portion, and a second edgewise coil having a spiral second coil portion, wherein the first coil portion and the second coil portion form a coil body made of only a single flat wire, and the second coil portion is disposed so as to surround the first coil portion and is disposed in a common area with the first coil portion in the axial direction.

2. The noise filter according to claim 1, wherein the flat wire has a folded portion and a pair of extending portions extending parallel to each other adjacent to each other from the folded portion, the pair of extending portions constituting the first coil portion and the second coil portion, the first edgewise coil being continuous with the extending end of one of the extending portions and having a first connecting terminal portion protruding from the first coil portion, the second edgewise coil being continuous with the extending end of the other of the extending portions and having a second connecting terminal portion protruding from the second coil portion, and the first connecting terminal portion and the second connecting terminal portion are located at one axial end of the first coil portion and the second coil portion.

3. A noise filter as described in claim 2, wherein the first connection terminal portion and the second connection terminal portion are arranged in positions that are rotationally symmetrical when viewed in the axial direction of the first coil portion and the second coil portion.

4. A noise filter according to any one of claims 1 to 3, wherein the first coil portion is arranged radially inward, and the second coil portion is arranged radially outward.

5. A noise filter according to claim 2 or claim 3, wherein the first connection terminal abuts against the second coil portion in the axial direction, and the second connection terminal abuts against the first coil portion in the axial direction.

6. A noise filter as claimed in claim 2 or claim 3, wherein the pair of extension portions includes a first extension portion constituting the first coil portion and a second extension portion constituting the second coil portion, and the first extension portion and the second extension portion are arranged alternately in the axial direction of the first coil portion and the second coil portion.

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