Edgewise coil and method for manufacturing edgewise coil

Abstract

The present invention improves workability in bending a rectangular wire.　An edgewise coil (20) includes a first coil section (22A) and a second coil section (22B) formed by bending a rectangular wire (30). In the axial-direction view in which the first coil section (22A) is viewed in the axial direction, the first coil section (22A) has a plurality of first linear sections (23A) and first bent sections (24A) that connect circumferentially adjacent first linear sections (23A) to each other. The first bent sections (24A) have narrowed sections (25) having a smaller cross-sectional area than the first linear sections (23A). In the axial-direction view, the second coil section (22B) has a plurality of second linear sections (23B) and second bent sections (24B) that connect circumferentially adjacent second linear sections (23B) to each other. The second bent sections (24B) have narrowed sections (25) having a smaller cross-sectional area than the second linear sections (23B).

Description

Edgewise Coil and Method for Manufacturing Edgewise Coil

[0001] The present disclosure relates to an edgewise coil and a method for manufacturing an edgewise coil.

[0002] Patent Document 1 discloses an edgewise coil formed by helically winding a flat wire having a rectangular cross-sectional shape. The coil portion of the edgewise coil is formed into a square in an axial direction view when viewed parallel to the axis of the coil portion.

[0003] Japanese Patent Application Laid-Open No. 2019-021796

[0004] Since the flat wire is bent with the short side in the cross section facing the axial direction of the coil portion, there is a concern that stress concentration and irregular deformation may occur in the bent portion, and there is a problem that processing is difficult. In particular, in the case of a square coil portion, the bending curvature of the bent portion where two sides are connected at a right angle is large, so the processing difficulty is high.

[0005] The edgewise coil of the present disclosure has been completed based on the above circumstances, and aims to improve the workability when bending a flat wire.

[0006] The edgewise coil of the present disclosure includes a coil portion formed by bending a flat wire. The coil portion has, in an axial direction view when viewed in the axial direction of the coil portion, a plurality of straight portions and bent portions connecting the adjacent straight portions in the circumferential direction. The bent portion has a narrow portion with a smaller cross-sectional area than the straight portion.

[0007] According to the present disclosure, it is possible to improve the workability when bending a flat wire.

[0008] FIG. 1 is a perspective view of the 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 X-X of FIG. 2. FIG. 6 is a cross-sectional view taken along line Y-Y of FIG. 3. FIG. 7 is a plan view showing the manufacturing process of the edgewise coil.

[0009] [Description of Embodiments of the Disclosure] First, embodiments of the Disclosure will be listed and described. Any combination of the following embodiments, to the extent that they do not cause contradictions, is also included as a form for carrying out the invention. The edgewise coil of the Disclosure (1) comprises a coil portion formed by bending a flat wire, the coil portion having, in an axial view when the coil portion is viewed in the axial direction, a plurality of straight portions and a bent portion connecting adjacent straight portions in the circumferential direction, the bent portion having a narrow portion with a smaller cross-sectional area than the straight portions. According to the configuration of the Disclosure, in the process of bending a flat wire so as to bend the plate thickness surface in an axial view, there is a concern that stress concentration or abnormal deformation may occur in the bent portion. However, since the bent portion has a narrow portion with a smaller cross-sectional area than the straight portions, the stress generated in the bent portion during bending is small, and there is no risk of abnormal deformation of the bent portion. Therefore, it is possible to improve the processability when bending a flat wire into a rectangular tube shape.

[0010] (2) In (1), it is preferable that a pair of opposing surfaces facing each other in the circumferential direction of the coil portion are formed in the region of the bent portion from the narrow portion to the inner peripheral edge of the coil portion. With this configuration, at the inner peripheral edge of the bent portion, two straight portions are arranged in close proximity in the circumferential direction, so that the strength of the magnetic field at the bent portion does not become extremely low.

[0011] (3) In (2), it is preferable that the pair of opposing surfaces are in contact with each other. With this configuration, the pair of opposing surfaces are in contact in the circumferential direction, which stabilizes the shape of the bent portion.

[0012] (4) In (3), it is preferable that the pair of opposing surfaces are in surface contact. With this configuration, since the cross-sectional area of ​​the narrow portion is smaller than that of the straight portion, there is a concern that the electrical resistance will increase in the bent portion. However, by having the pair of opposing surfaces in surface contact, the contact area between the pair of opposing surfaces increases, so the increase in electrical resistance in the bent portion can be avoided.

[0013] (5) The method for manufacturing the edgewise coil described in (1) involves forming a plurality of narrow sections by forming a plurality of notches on the side edge along the length direction of the flat wire while the flat wire is in a straight shape, and then forming the bent section by bending the flat wire at the narrow section. According to this manufacturing method, by forming a plurality of narrow sections on a straight flat wire in advance, the straight section and the bent section of the coil can be formed continuously.

[0014] In (6) and (5), it is preferable to bend the rectangular wire so that the notch closes in the narrow portion. According to this manufacturing method, a bent portion having a pair of opposing surfaces on the inner circumference side of the narrow portion can be formed.

[0015] [Details of Embodiments of the Disclosure] [Example 1] An embodiment of the present disclosure, a noise filter 1 of Embodiment 1, will be described with reference to Figures 1 to 7. The present invention is not limited to these examples, but is shown by the claims, and all modifications within the meaning and range equivalent to the claims are included. In Embodiment 1, the front-to-back direction is defined as the F direction in Figures 1, 2, 4, and 6. The up-and-down direction is defined as the H direction in Figures 1, 3 to 5. The left-to-right direction is defined as the L direction in Figures 1 to 3, 5, and 6. The up-and-down direction and the axial direction are used synonymously.

[0016] The noise filter 1 of this embodiment 1 comprises one core 10 and one edgewise coil 20. The core 10 is made of a magnetic material such as iron, or a material containing a magnetic material. The core 10 has a prismatic shaft portion 11, and upper flange portions 12 and lower flange portions 13 formed at both ends of the shaft portion 11 in the axial direction. The core 10 is used with its axis oriented in the vertical direction.

[0017] In an axial view (plan view) of the core 10 along the axis of the shaft portion 11, the shaft portion 11, the upper flange portion 12, and the lower flange portion 13 form a square. 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.

[0018] The edgewise coil 20 is a single component formed by bending a flat rectangular wire 30. As shown in Figure 5, the cross-sectional shape of the flat rectangular wire 30 is a rectangle with a relatively large ratio between the long side in the horizontal direction and the short side in the vertical direction. The flat rectangular wire 30 is a wire in which a conductor (not shown) made of a conductive material such as copper, aluminum, or carbon nanotubes is surrounded by an insulating coating (not shown).

[0019] 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 coil body portion 22 is composed of the first coil portion 22A and the second coil portion 22B.

[0020] In an axial view, the coil body 22 (first coil section 22A and second coil section 22B) forms a square as a whole. The coil body 22 is arranged to coaxially surround the shaft section 11 in an axial view. The coil body 22 is placed on the upper surface of the lower flange section 13. In a front view of the noise filter 1, the coil body 22 is arranged to be sandwiched between the upper flange section 12 and the lower flange section 13. The first coil section 22A is located radially inward, and its inner circumferential surface is positioned directly (without intervening other members) and in close proximity to the outer circumferential surface of the shaft section 11. The second coil section 22B is located radially outward, and its inner circumferential surface is positioned directly and in close proximity to the outer circumferential surface of the first coil section 22A.

[0021] The first coil section 22A is a portion formed by bending a rectangular wire 30 spirally so that it forms a square when viewed in the axial direction. The rectangular wire 30 is bent so that the thickness surface is bent when viewed in the axial direction. The thickness surface is the surface corresponding to the short side in the cross-section of the rectangular wire 30. The first coil section 22A has four first straight sections 23A and four first bent sections 24A that connect two first straight sections 23A that are perpendicular to each other and adjacent in the circumferential direction. The second coil section 22B is a portion formed by bending a rectangular wire 30 spirally so that it forms a square when viewed in the axial direction. The second coil section 22B has four second straight sections 23B and four second bent sections 24B that connect two second straight sections 23B that are perpendicular to each other and adjacent in the circumferential direction. At the lowest part of the coil body 22, the first base end 28A of the first coil section 22A and the second base end 28B of the second coil section 22B are connected in a U-turn shape via the folded portion 29.

[0022] The inner square region of the first coil section 22A is positioned so as to tuck beneath the upper flange section 12. The projections 14 of the upper flange section 12 are pressed against the upper surfaces of the two first straight sections 23A located at the top of the first coil section 22A. The first coil section 22A is held in a state where it is sandwiched vertically between the lower flange section 13 and the upper flange section 12 by the pressure of the projections 14.

[0023] The first connection terminal portion 27A is a portion that extends to the right without bending from the right end (extended end) of the first straight portion 23A, which is located at the uppermost stage of the first coil portion 22A. The portion of the first connection terminal portion 27A that protrudes to the right of the upper flange portion 12 is positioned so as to abut or face the uppermost end surface of the second straight portion 23B from above. Therefore, there is no risk of the second coil portion 22B moving upward relative to the first coil portion 22A.

[0024] The second connection terminal portion 27B is a portion that extends to the left from the left end (extended end) of the second straight portion 23B, which is located at the uppermost stage of the second coil portion 22B. The second connection terminal portion 27B has a first bent portion 27C that bends backward along the left edge of the upper flange portion 12, and a second bent portion 27D that bends to the left at the rear end of the portion that extends backward from the first bent portion 27C. The second bent portion 27D is positioned so as to abut or face the uppermost end surface of the first straight portion 23A from above. Therefore, there is no risk of the first coil portion 22A moving upward relative to the second coil portion 22B.

[0025] In the axial direction of the core 10 and edgewise coil 20, the first connection terminal portion 27A and the second connection terminal portion 27B are located only at one end (upper end). In an axial view, the first connection terminal portion 27A and the second connection terminal portion 27B are arranged in a rotationally symmetrical positional relationship. A communication circuit (not shown) that is the target of noise countermeasures by the noise filter 1 is connected to the first connection terminal portion 27A and the second connection terminal portion 27B. One of the first connection terminal portion 27A and the second connection terminal portion 27B functions as an input terminal, and the other functions as an output terminal.

[0026] The first coil section 22A and the second coil section 22B are formed by bending a rectangular wire 30. The rectangular wire 30 is pre-processed to facilitate bending. The rectangular wire 30 is manufactured in a straight state. When the rectangular wire 30 is in a straight state, multiple notches 33 are formed on both side edges along the length of the rectangular wire 30 by partially cutting and removing them. The positions where the notches 33 are formed are the parts that will be formed by bending as a folded portion 29, multiple first bent portions 24A, multiple second bent portions 24B, a first bent portion 27C, and a second bent portion 27D. In the notches 33, the conductor constituting the rectangular wire 30 is exposed. In a plan view of the rectangular wire 30 viewed parallel to the short side of its cross-section, the notches 33 form a right-angled isosceles triangle. The dimensions of the notch 33 formed in the width direction perpendicular to the side edge of the rectangular wire 30 are half the width dimension of the rectangular wire 30. The portion of the rectangular wire 30 adjacent to the notch 33 in the width direction is defined as the narrow portion 25.

[0027] The flat rectangular wire 30, on which the notch 33 is formed, is bent at the narrow portion 25, starting from the end that will become the first connection terminal portion 27A, to form the first edgewise coil 21A (first coil portion 22A and first connection terminal portion 27A). The first edgewise coil 21A may also be formed by bending the narrow portion 25 starting from the folded portion 29 side. After forming the first edgewise coil 21A, the second edgewise coil 21B is formed. The second edgewise coil 21B (second coil portion 22B and second connection terminal portion 27B) is formed by bending the narrow portion 25 starting from the folded portion 29 side.

[0028] The cross-sectional area of ​​the narrow portion 25 in the rectangular wire 30 is smaller than the cross-sectional area of ​​the region other than the narrow portion 25. Therefore, when bending the narrow portion 25, the compressive stress generated on the inside of the bend and the tensile stress generated on the outside of the bend are smaller than when bending the other parts of the wire. Thus, when bending the narrow portion 25, abnormal deformation is less likely to occur in the narrow portion 25. Therefore, bending is easier.

[0029] Since the notch 33 forms a right-angled isosceles triangle, the folded portion 29, the first bent portion 24A, the second bent portion 24B, the first bent portion 27C, and the second bent portion 27D formed by the bending of the narrow portion 25 have a pair of opposing surfaces 26 facing each other in the circumferential direction formed by the two inner surfaces constituting the notch 33. Since the notch 33 forms a right-angled isosceles triangle and the narrow portion 25 is bent at a right angle, the pair of opposing surfaces 26 come into contact with each other in a surface contact state. When the notch 33 is cut, a conductor is exposed on the inner surface of the notch 33, so the pair of opposing surfaces 26 are electrically connected to each other. The inner edge of the bend in the first bent portion 24A does not become curved because the side edges of the first straight portion 23A abut at a right angle. Therefore, in an axial view, the gap between the outer edge of the shaft portion 11 and the inner edge of the first coil portion 22A can be narrowed. Similarly, the inner edges of the bends in the folded portion 29, the second bend portion 24B, the first bend portion 27C, and the second bend portion 27D do not become curved surfaces because the straight side edges of the flat wire 30 are abutted at right angles to each other.

[0030] The edgewise coil 20 of this embodiment 1 comprises a first coil portion 22A and a second coil portion 22B formed by bending a flat wire 30. The first coil portion 22A, when viewed in the axial direction, has a plurality of first straight portions 23A and a first bent portion 24A connecting adjacent first straight portions 23A in the circumferential direction. The second coil portion 22B, when viewed in the axial direction, has a plurality of second straight portions 23B and a second bent portion 24B connecting adjacent second straight portions 23B in the circumferential direction. The first bent portion 24A has a narrow portion 25 with a smaller cross-sectional area than the first straight portion 23A, and the second bent portion 24B has a narrow portion 25 with a smaller cross-sectional area than the second straight portion 23B.

[0031] With this configuration, in the process of bending the rectangular wire 30 so that the plate thickness surface is bent when viewed in the axial direction, there is a concern that stress concentration or abnormal deformation may occur at the first bent portion 24A and the second bent portion 24B. However, since the first bent portion 24A and the second bent portion 24B have narrower sections 25 with a smaller cross-sectional area than the first straight portion 23A and the second straight portion 23B, the stress generated in the first bent portion 24A and the second bent portion 24B during bending is small, and there is no risk of abnormal deformation occurring in the first bent portion 24A and the second bent portion 24B. Therefore, the processability when bending the rectangular wire 30 into a rectangular tube shape can be improved.

[0032] In the region of the first bent portion 24A from the narrow portion 25 to the inner periphery of the first coil portion 22A, a pair of opposing surfaces 26 are formed that face each other in the circumferential direction of the first coil portion 22A. In the region of the second bent portion 24B from the narrow portion 25 to the inner periphery of the second coil portion 22B, a pair of opposing surfaces 26 are also formed that face each other in the circumferential direction of the second coil portion 22B. With this configuration, at the inner periphery of the first bent portion 24A, the two first straight portions 23A are arranged in close proximity in the circumferential direction, so that the strength of the magnetic field at the first bent portion 24A does not become extremely low. Similarly, at the inner periphery of the second bent portion 24B, the two second straight portions 23B are arranged in close proximity in the circumferential direction, so that the strength of the magnetic field at the second bent portion 24B does not become extremely low.

[0033] The pair of opposing surfaces 26 are in contact with each other. With this configuration, the pair of opposing surfaces 26 are in contact in the circumferential direction, which stabilizes the bent shape of the first bent portion 24A and the second bent portion 24B. Since the cross-sectional area of ​​the narrow portion 25 is smaller than that of the first straight portion 23A and the second straight portion 23B, there is a concern that the electrical resistance will increase in the first bent portion 24A and the second bent portion 24B. However, because the pair of opposing surfaces 26 are in surface contact, the contact area between the pair of opposing surfaces 26 increases, which prevents an increase in the electrical resistance in the first bent portion 24A and the second bent portion 24B.

[0034] The edgewise coil 20 is manufactured by performing the following first and second processing steps. In the first processing step, as shown in Figure 7, while the rectangular wire 30 is in a straight shape, multiple narrow sections 25 are formed by creating multiple notches 33 on the side edges along the length direction of the rectangular wire 30. In the second processing step that follows, the rectangular wire 30 is bent at the narrow sections 25 to form the first bent section 24A and the second bent section 24B.

[0035] According to this manufacturing method, by forming a plurality of narrow sections 25 in the straight rectangular wire 30 in advance, the first straight section 23A and the first bent section 24A in the first coil section 22A can be formed continuously, and the second straight section 23B and the second bent section 24B in the second coil section 22B can also be formed continuously. In the second processing step, the rectangular wire 30 is bent so that the notches 33 in the narrow sections 25 are closed. According to this processing step, the first bent section 24A and the second bent section 24B, which have a pair of opposing surfaces 26 on the inner circumference side of the narrow section 25, can be formed.

[0036] [Other Embodiments] The present invention is not limited to the embodiments described above and in the drawings, but is shown in the claims. The present invention includes the meaning of equivalences to the claims and all modifications within the claims, and also includes the following embodiments. The narrow portion may constitute only the inner periphery of the coil portion. The narrow portion may be bent in the direction of opening the notch. The opposing surfaces may consist only of curved surfaces, or may consist of flat and curved surfaces. The area in which a pair of opposing surfaces are formed in the width direction of the rectangular wire may be less than half the width dimension of the rectangular wire, or greater than half. The pair of opposing surfaces may be facing each other in a non-contact state. The pair of opposing surfaces may be in point contact or line contact at multiple locations. The area in which a pair of opposing surfaces are in surface contact may be the entire area of ​​the opposing surfaces, or only a part of the area of ​​the opposing surfaces. The pair of opposing surfaces may not be formed in the bent portion, and the narrow portion may constitute the inner periphery of the bent portion. In a plan view (axial view), the coil body is not limited to a square, but may be formed into polygons such as rectangles or hexagons, or into circles or ellipses. One of the two terminal connection parts may be placed at the upper end of the coil body, and the other terminal may be placed at the lower end of the coil body. An edgewise coil may have only one coil part. The plan view shape of the notch is not limited to a right-angled isosceles triangle, but may be a scalene triangle, a shape other than a triangle, or a slit-like cutout. The core shape is not limited to a prism, but may be a cylinder, an elliptical column in plan view, etc.

[0037] 1...Noise filter 10...Core 11...Shaft 12...Upper flange 13...Lower flange 14...Protrusion 20...Edgewise coil 22...Coil body 22A...First coil section (coil part) 22B...Second coil section (coil part) 23A...First straight section (straight part) 23B...Second straight section (straight part) 24A...First bent section (bent part) 24B...Second bent section (bent part) 25...Narrow section 26...Opposite surface 27A...First connection terminal section 27B...Second connection terminal section 27C...First bend 27D...Second bend 28A...First base end 28B...Second base end 29...Folded section 30...Flat wire 33...Notch

Claims

1. An edgewise coil comprising a coil portion formed by bending a flat wire, wherein the coil portion, when viewed in the axial direction, has a plurality of straight sections and bent sections connecting adjacent straight sections in the circumferential direction, and the bent sections have narrow sections with a smaller cross-sectional area than the straight sections.

2. The edgewise coil according to claim 1, wherein a pair of opposing surfaces facing each other in the circumferential direction of the coil portion are formed in the region of the bent portion from the narrow portion to the inner peripheral edge of the coil portion.

3. The edgewise coil according to claim 2, wherein the pair of opposing surfaces are in contact with each other.

4. The edgewise coil according to claim 3, wherein the pair of opposing surfaces are in surface contact.

5. A method for manufacturing the edgewise coil according to claim 1, comprising: forming a plurality of narrow portions by forming a plurality of notches on the side edge along the longitudinal direction of the flat wire while the flat wire is in a straight shape; and forming the bent portion by bending the flat wire at the narrow portion.

6. The method for manufacturing an edgewise coil according to claim 5, wherein the flat wire is bent so that the notch closes in the narrow portion.

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