JP2022158845A - Insulation wire and wire harness - Google Patents

Abstract

To provide an insulation wire which allows easy processing involving removal of insulation coating while having a flat part where the cross section of a conductor is flat-shaped; and to provide a wire harness with such an insulation wire.SOLUTION: An insulation wire 1 has a conductor 11 obtained by twisting a plurality of single wires, and insulation coating 13 coating an outer periphery of the conductor 11. The insulation wire 1 has a flat part 20 and a low flat part 30 along an axial direction x with each of the single wires constituting the conductor 11 and the insulation coating 13 continuing mutually. The outer shape of the conductor 11 on a cross section orthogonal to the axial direction x of the insulation wire 1, on the flat part 20, has a flat shape, and on the low flat part 30, has a shape with a flatness degree smaller than that of the flat part 20. An adhesion force between the conductor 11 and the insulation coating 13 is smaller than that of the flat part 20 on the low flat part 30.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to insulated wires and wire harnesses.

A flat cable constructed using flat conductors is known. By using a flat cable, it is possible to reduce the space occupied during wiring as compared with the case of using a general electric wire having a conductor with a substantially circular cross section.

In conventional general flat cables, rectangular conductors are often used as conductors, as disclosed in Patent Documents 1 and 2 and the like. A rectangular conductor is formed by forming a metal single wire into a rectangular cross section. In addition, Patent Documents 3 to 5 filed by the applicants disclose electric wire conductors in which a twisted wire obtained by twisting a plurality of strands is molded into a flat shape from the viewpoint of achieving both flexibility and space saving. there is

JP 2014-130739 A JP 2019-149242 A WO2019/093309 WO2019/093310 WO2019/177016

As disclosed in Patent Documents 3 to 5, a flat electric wire provided with a conductor formed by flattening a stranded wire is excellent in both space saving and flexibility. However, for flat electric wires of this type, tools such as a wire stripper for removing the insulating coating, and terminals attached to the ends have conventionally been used for general electric wires with a substantially circular cross section (round electric wires). cannot be applied as is. Moreover, flat electric wires tend to have a higher adhesion between the insulating coating and the conductor due to the larger surface area of the conductor compared to the round electric wire having the same conductor cross-sectional area. Then, a large force is required to remove the insulation coating from the end portion of the flat electric wire in order to attach a terminal or the like. As described above, it may be difficult to process the terminal portion of the flat electric wire or the like, which involves removal of the insulating coating.

In view of the above, an insulated wire that has a flat portion with a flattened cross-section of the conductor and can be easily processed with removal of the insulation coating, and a wire harness equipped with such an insulated wire. The task is to

An insulated wire according to a first embodiment of the present disclosure is an insulated wire including a conductor in which a plurality of strands are twisted together, and an insulating coating covering an outer periphery of the conductor, wherein the conductor comprises the Each of the strands of wire and the insulating coating are connected to each other to have a flat portion and a low flat portion along the axial direction, and the outer shape of the conductor in a cross section orthogonal to the axial direction of the insulated wire is , the flat portion has a flat shape, and the low flat portion has a shape with a smaller degree of flatness than the flat portion, and the adhesion between the conductor and the insulating coating is such that in the low flat portion, It is smaller than the flat portion.

In the insulated wire according to the second embodiment of the present disclosure, a conductor in which a plurality of strands are twisted is compressed into a flat shape, and the outer periphery is covered with an insulating coating to form an insulated wire, and then in the axial direction of the insulated wire. A force is applied from the outside in the width direction of the flat shape toward the inside in a partial region along the flat shape to reduce the flatness of the conductor, thereby forming a low flat portion and the low flat portion. It is manufactured by leaving the area other than the flattened area as a flat portion.

The insulated wire according to the third embodiment of the present disclosure is an insulated wire formed by covering the outer periphery of a conductor in which a plurality of wires are twisted with an insulating coating, and then partially extending along the axial direction of the insulated wire. In the region, a flat portion is formed by increasing the flatness of the conductor by applying a force to compress the insulated wire from directions facing each other, and the region other than the flat portion is a low flat portion It is manufactured by leaving as

A wire harness of the present disclosure includes the insulated wire.

The insulated wire and the wire harness according to the present disclosure are an insulated wire that can be easily processed by removing the insulation coating while having a flat portion in which the cross section of the conductor is flat, and such an insulated wire. It becomes a wire harness with

1A-1C are schematic diagrams illustrating an insulated wire according to one embodiment of the present disclosure. FIG. 1A is a perspective view. 1B is a cross-sectional view showing a flat portion corresponding to the AA cross section in FIG. 1A, and FIG. 1C is a cross-sectional view showing a low flat portion corresponding to the BB cross section in FIG. 1A. In each figure, the strands constituting the conductor are omitted. 2A and 2B are cross-sectional views respectively showing a flat portion and a low flat portion of the insulated wire according to the embodiment. FIG. 3 is a schematic diagram showing an insulated wire having a plurality of regions with different flattening directions as flattened portions. FIG. 3A is a perspective view. FIG. 3B is a cross-sectional view showing the first region corresponding to the CC cross section and the third region corresponding to the EE cross section in FIG. 3A. FIG. 3C is a cross-sectional view showing the second area corresponding to the DD cross section in FIG. 3A. In each figure, the strands constituting the conductor are omitted. FIG. 4 is a diagram for explaining the method of manufacturing the insulated wire according to the above embodiment. FIG. 5 is a diagram illustrating a method of manufacturing an insulated wire according to another embodiment of the present disclosure. 6A and 6B are tables summarizing cross-sectional images and various evaluation results for the flat portion and low flat portion of Sample 1 and Sample 2, respectively.

[Description of Embodiments of the Present Disclosure]
First, the embodiments of the present disclosure will be listed and described.
An insulated wire according to a first embodiment of the present disclosure is an insulated wire including a conductor in which a plurality of strands are twisted together, and an insulating coating covering an outer periphery of the conductor, wherein the conductor comprises the Each of the strands of wire and the insulating coating are connected to each other to have a flat portion and a low flat portion along the axial direction, and the outer shape of the conductor in a cross section orthogonal to the axial direction of the insulated wire is , the flat portion has a flat shape, and the low flat portion has a shape with a smaller degree of flatness than the flat portion, and the adhesion between the conductor and the insulating coating is such that in the low flat portion, It is smaller than the flat portion.

The insulated wire has a flat portion in which the conductor has a flat shape and a low-flat portion in which the flatness is small. Compared to the flat part, the low flat part has a cross-sectional shape that is closer to that of a conventional round electric wire. By performing these processes on the flat portion, it is easy to apply tools such as wire strippers and external members such as terminals that are conventionally used for round electric wires. Furthermore, since the adhesion force between the conductor and the insulating coating is smaller in the low flat portion than in the flat portion, the insulating coating can be removed with a small force in the low flat portion. In this way, by performing processing on the low flat portion while obtaining the effect of improving space saving by the flat portion, it is possible to easily perform processing of the insulated wire that involves removal of the insulation coating. . In the flat part, the insulation coating adheres to the conductor with a large adhesive force, so even if the adhesion strength is small in the low flat part, the positional deviation between the insulation coating and the conductor occurs as a whole insulated wire. In addition, heat dissipation from the conductor through the insulating coating can be ensured during energization.

In this way, an insulated wire having both a flat portion and a low flat portion, and in which the adhesive force between the conductor and the insulation coating is reduced in the low flat portion is a flat conductor with an insulation coating formed on the outer periphery of the flat conductor. In a part of the electric wire, a force is applied to compress the conductor from the outside in the width direction of the flat shape to deform the conductor, thereby lowering the flatness of the conductor and forming a low-flat portion. be able to. Alternatively, in a part of a low-flat electric wire, such as a round electric wire, in which an insulating coating is formed on the outer periphery of a conductor with a small flatness, a force is applied so as to compress the conductor from a direction facing each other to deform it, thereby flattening the conductor. Such an insulated wire can be easily manufactured by a method of increasing the strength and forming a flat portion.

Here, it is preferable that the adhesion force between the conductor and the insulating coating is 20% or more smaller in the low flat portion than in the flat portion. Then, the insulating coating can be removed particularly easily in the low flat portion.

It is preferable that a porosity, which is a ratio of voids not occupied by wires, to the area of the region surrounded by the inner circumference of the insulating coating in the cross section is larger in the low flat portion than in the flat portion. In the low-flat portion, the gap formed between the conductor and the insulating coating reduces the adhesion between the conductor and the insulating coating. In addition, the voids formed between the conductor and the insulating coating and the voids formed between the strands of the conductor increase the flexibility of the low-flat portion. Therefore, since the porosity of the low flat portion is larger than that of the flat portion, it is possible to effectively improve the peelability and flexibility of the insulating coating in the low flat portion. An insulated wire in which the low flat portion has a higher porosity than the flat portion can be easily manufactured by applying force to the flat electric wire to form the low flat portion.

In this case, the porosity in the cross section is preferably 20% or more higher in the low flat portion than in the flat portion. As a result, the ease of peeling and the flexibility of the low-flat portion can be particularly effectively enhanced.

In the cross section of the low-flat portion, regions outside the conductor along directions corresponding to the width direction and the height direction of the flat shape are defined as a width direction outside conductor region and a height direction outside conductor region, respectively. Preferably, in the width direction outside conductor region, a gap larger than that in the height direction outside conductor region is formed between the conductor and the insulating coating. As described above, the gap formed between the conductor and the insulating coating reduces the adhesion between the conductor and the insulating coating. When a force is applied to the flat electric wire from the outside in the width direction to form the low flat portion, in the low flat portion, the dimension of the conductor in the width direction is reduced, so that in the width direction outside conductor area, there is a gap between the conductor and the insulation coating. voids are likely to form.

In the cross section, the difference in length of the inner periphery of the insulating coating between the flat portion and the low flat portion is preferably 5% or less of the length of the inner periphery of the insulating coating in the flat portion. . When the flat electric wire is deformed by applying force to form the low flat portion, the change in length of the inner circumference of the insulating coating is restricted by the inner peripheral surface of the insulating coating. Therefore, an insulated wire in which the difference in the length of the inner circumference of the insulating coating between the flat portion and the low flat portion is suppressed to 5% or less of the length of the inner circumference of the insulating coating in the flat portion is made from the flat electric wire. As such, it can be manufactured easily.

The insulated wire may have, as the flattened portion, a plurality of regions having different flattened directions. The flat portion exhibits high flexibility in bending in the height direction of the flat shape. Therefore, if the insulated wire is provided with a plurality of regions having different flattened directions as the flattened portions, each region can be easily bent in the height direction of each flattened shape, so that a single insulated wire can be formed. A plurality of portions having different bending directions can be formed inside. For example, when an insulated wire needs to be bent into a complicated shape such as for three-dimensional routing, for each part of the insulated wire, multiple regions are formed so that the height direction of the flat shape faces the direction you want to bend. is set to form a flat portion, the wire can be bent without difficulty even if it has a complicated shape.

The insulated wire preferably has the low flat portion on at least one side of the flat portion along the axial direction. An insulated wire with a low flat part on at least one side of the flat wire, such as a terminal part, utilizes the space-saving properties of the flat part for wiring, and uses the low flat part to remove insulation coating, terminals, etc. Processing such as attachment of a connector can be easily performed. By processing the low flat portion having a cross-sectional shape with low flatness, there is no need to use a flat terminal or connector that matches the shape of the flat portion.

In the insulated wire according to the second embodiment of the present disclosure, a conductor in which a plurality of strands are twisted is compressed into a flat shape, and the outer periphery is covered with an insulating coating to form an insulated wire, and then in the axial direction of the insulated wire. A force is applied from the outside in the width direction of the flat shape toward the inside in a partial region along the flat shape to reduce the flatness of the conductor, thereby forming a low flat portion and the low flat portion. It is manufactured by leaving the area other than the flattened area as a flat portion.

In the insulated wire according to the second embodiment, the flat electric wire in which the flat conductor is covered with an insulating coating is subjected to an operation of compressing the conductor by applying force from the outside in the width direction, so that the low flat portion , the adhesion between the conductor and the insulation coating is reduced. Therefore, in the low-flat portion, it becomes easier to perform processing involving removal of the insulation coating, in combination with the effect of the low flatness itself. Therefore, the insulated wire is excellent in both space saving properties due to the flattened portion and ease of processing in the low flattened portion. Furthermore, the operation of applying force to the flat wire from the outside in the width direction to compress the conductor tends to form a void not occupied by the wires in the region inside the insulation coating in the low flat portion. Such voids are highly effective in reducing adhesion between the conductor and the insulating coating and improving flexibility in the low-flat portion.

The insulated wire according to the third embodiment of the present disclosure is an insulated wire formed by covering the outer periphery of a conductor in which a plurality of wires are twisted with an insulating coating, and then partially extending along the axial direction of the insulated wire. In the region, a flat portion is formed by increasing the flatness of the conductor by applying a force to compress the insulated wire from directions facing each other, and the region other than the flat portion is a low flat portion It is manufactured by leaving as

In the insulated wire according to the third form as well, the insulated wires with low flatness are compressed from the directions facing each other, so that the adhesion between the conductor and the insulation coating is reduced at the low flat portion rather than at the flat portion. power becomes smaller. Therefore, in the low-flat portion, it is easy to perform the processing accompanied by the removal of the insulating coating in combination with the effect of the low flatness itself. Therefore, the insulated wire is excellent in both space saving properties due to the flattened portion and ease of processing in the low flattened portion. By applying force to an insulated wire that has a conductor with low flatness such as a round wire and deforming it to form a flattened portion, an insulated wire that integrates a low flattened portion and a flattened portion can be converted into a general-purpose insulated wire. As a raw material, it can be easily formed.

A wire harness according to the present disclosure includes the insulated wire according to the present disclosure. As described above, in the insulated wire according to the present disclosure, the flat portion exhibits high space saving properties and flexibility, and the low flat portion can be easily processed to remove the insulating coating. The wire harness as a whole can also be suitably used for applications such as connection between devices in places where space is limited, such as in automobiles, by utilizing these characteristics.

[Details of the embodiment of the present disclosure]
Insulated wires and wire harnesses according to embodiments of the present disclosure will be described in detail below with reference to the drawings. In this specification, regarding the shape of each part of the insulated wire, the concept of the shape and arrangement of the member, such as straight, parallel, and vertical, is approximately ±15% in length and approximately ±15° in angle. Errors from the geometrical concept are included within the allowable range for this type of insulated wire, such as deviation of In this specification, unless otherwise specified, the cross section of an insulated wire or conductor indicates a cross section taken perpendicularly to the axial direction (longitudinal direction).

<Overview of insulated wire>
FIG. 1A shows a perspective view of an insulated wire 1 according to an embodiment of the present disclosure. 1B and 1C are simplified cross-sectional views taken along lines AA and BB in FIG. 1A, respectively. Further, FIGS. 2A and 2B display in detail the cross-sections of the flattened portion corresponding to FIG. 1B and the low flattened portion corresponding to FIG. 1C, respectively.

An insulated wire 1 according to this embodiment has a conductor 11 and an insulating coating 13 . The conductor 11 is configured as a twisted wire in which a plurality of wires 12 are twisted together. The insulating coating 13 covers the entire circumference of the conductor 11 . The insulated wire 1 has a flat portion 20 and a low flat portion 30 along the axial direction (x direction). The flat portion 20 and the low flat portion 30 are integrally continuous along the axial direction of the insulated wire 1 . That is, the wires 12 forming the conductor 11 are integrally continuous between the flat portion 20 and the low flat portion 30 . Further, the insulating coating 13 that covers the conductor 11 is also integrally continuous between the flat portion 20 and the low flat portion 30 .

In the flat portion 20, the cross section of the conductor 11 has a flat shape. Here, the fact that the outer shape of the conductor 11 has a flat shape means that the length of the longest straight line among the straight lines that cross the cross section parallel to the sides or diameters that make up the cross section and that covers the entire cross section. A state in which w is greater than the height h, which is the length of a straight line that is perpendicular to the straight line and covers the entire cross section. The cross section of the conductor 11 may have any specific shape as long as it is flat, but in the present embodiment, the cross section of the conductor 11 has a shape that approximates a rectangle. Flat shapes other than rectangles include, for example, elliptical, oval, and oval shapes (shapes in which circular arcs are joined to both ends of a rectangle). From the viewpoint of enhancing space saving and enhancing continuity with the low-flat portion 30, the aspect ratio w/h of the flat portion 20 is preferably about 2 or more and 6 or less, for example. Hereinafter, in the entire area of the insulated wire 1 including the low flat portion 30, the directions corresponding to the width direction and the height direction of the flat shape of the flat portion 20 are set to the width equivalent direction (y direction) and the height equivalent direction ( z-direction).

The low flat portion 30 has a shape in which the flatness of the conductor 11 is smaller than that of the flat portion 20 in cross section. Here, the low flatness of the conductor 11 means that the cross-sectional aspect ratio w/h of the conductor 11 is small and the cross-sectional shape is low in flatness. The specific shape of the low flat portion 30 is not particularly limited. A shape that can be approximated to a rectangle, ellipse, or oval with a small aspect ratio w/h can also be exemplified. The flatness of the low-flat portion 30 is preferably as small as possible, and it is particularly preferable that the low-flat portion 30 have a circular or square-like cross section with an aspect ratio w/h of 1. Furthermore, a form that can approximate a circular cross section is most preferable. However, if the aspect ratio w/h of the low-flat portion 30 is set to, for example, 2 or less, the effect of improving the workability of the low-flat portion 30, which will be described later, can be sufficiently obtained. Also, the aspect ratio w/h of the low-flat portion 30 may be approximately 20% or more and 70% or less of the aspect ratio w/h of the flat portion 20 . In the low-flat portion 30, it is preferable that the dimension w in the width equivalent direction is not smaller than the dimension h in the height equivalent direction (w/h≧1). In other words, it is preferable that the low flat portion 30 does not have a vertically long cross-sectional shape. However, this does not prevent the low flat portion 30 from having a vertically long cross-sectional shape. It is preferable to keep Furthermore, from the viewpoint of improving the workability of the low flat portion 30, the aspect ratio h/w of the low flat portion 30 should be 2 or less, like the aspect ratio w/h in the case of the oblong shape mentioned above. Just do it. Also, the aspect ratio h/w of the low-flat portion 30 may be approximately 20% or more and 70% or less of the aspect ratio w/h of the flat portion 20 .

As shown in FIG. 4, the insulated wire 1 integrally having the flat portion 20 and the low flat portion 30 can be suitably manufactured from the raw material flat wire 9 obtained by deforming the conductor 11 into a flat shape. . The raw material flat electric wire 9 can be manufactured by compressing a conductor 11 having a circular cross section in which a plurality of strands 12 are twisted together into a flat shape and covering the outer periphery of the conductor 11 with an insulating coating 13 . At this time, as described in Patent Documents 3 to 5, the conductor 11 can be suitably compressed by using rollers from both sides in the height direction and optionally from both sides in the width direction. can. Formation of the insulating coating 13 on the outer circumference of the compressed conductor 11 is preferably carried out by extrusion molding of a resin composition. In the raw material flat electric wire 9 obtained in this way, in a part of the region along the axial direction, specifically, in the region where the low flat portion 30 is desired to be formed, from outside the raw material flat electric wire 9 in the width direction (y direction) from the outside toward the inside to deform the conductor 11 . The application of the force F1 reduces the dimension of the conductor 11 in the width direction and reduces the flatness of the conductor 11 . By this operation, the low flat portion 30 can be formed. The force F1 can be applied by manual processing, or by processing using a tool such as a hammer, a molding die, a press machine, or the like. The force F1 applied to the conductor 11 at this time is preferably smaller than the force applied for flattening the conductor 11 when forming the raw flat wire 9 . In the raw material flat electric wire 9 , the area other than the area where the low flat portion 30 is formed by the application of the force F1 is left as the flat portion 20 .

After forming the low-flat portion 30 by applying the force F1, it is better not to heat the insulating coating 13 at a location including the low-flat portion 30 to bring the insulating coating 13 into close contact with the conductor 11. good. This is to keep the adhesion between the conductor 11 and the insulating coating 13 small and leave many gaps in the region surrounded by the insulating coating 13 in the low flat portion 30, as will be described later. However, by heating the insulating coating 13 at a location including the low flat portion 30 to deform the insulating coating 13, a gap may be arranged at a desired location between the conductor 11 and the insulating coating 13. . For example, when the low-flat portion 30 has a vertically long cross-sectional shape (w/h<1), the gaps are unevenly distributed outside the conductor 11 in the direction corresponding to the height, that is, outside in the longitudinal direction. , a form in which the insulating coating 13 is deformed is conceivable.

The insulated wire 1 according to the present embodiment is provided with the flat portion 20 having a flat cross-sectional shape, so that it exhibits a high space saving property, and can be installed in a narrow space or in a state close to other members. It can also be suitably used for wiring. On the other hand, since the low-flat portion 30 has a cross-sectional shape with a low degree of flatness and has a cross-sectional shape similar to that of a conventional general round electric wire, tools and devices such as wire strippers that are applied to conventional round electric wires can be used. is used to facilitate processing such as removal of the insulating coating 13 from the low flat portion 30 . Also, as external members such as terminals and connectors to be attached to the insulated wire 1, conventional ones for round wires can be easily applied without preparing special shapes matching the flat shape. By processing the insulated wire 1 using the low-flat portion 30 in this manner, processing such as removal of the insulating coating 13 can be easily performed. The insulated wire 1 according to the present embodiment is suitable for places where wiring space is limited, such as in automobiles, and processing involving removal of the insulating coating 13 is required for connection with external members. can be applied.

In the present embodiment, in the axial direction of the insulated wire 1, the position and number of the low flat portions 30 are not particularly limited. A flat portion 30 may be formed. As described above, the low flat portion 30 can be formed only by applying the force F1 that deforms the conductor 11 from the outside of the insulating coating 13 to the raw material flat electric wire 9. Therefore, using the common raw material flat electric wire 9, Various insulated wires 1 having different locations where the low flat portion 30 is required can be easily manufactured. As a preferred form, a form having low flat portions 30 on at least one side or both sides of the flat portion 20 along the axial direction of the insulated wire 1 can be cited. Furthermore, a low flat portion 30 is formed on at least one end or both ends of one insulated wire 1, and the remaining region such as the middle region of the insulated wire 1 sandwiched between the two low flat portions 30 is A form of the flat portion 20 is preferable. Then, when routing the insulated wire 1, the space-saving property of the flat portion 20 can be used for routing in the middle area, etc., and at least one of the ends of the insulated wire 1 can be conveniently connected to an external member. When it is more convenient to provide the low flat portion 30 than the flat portion 20 from the viewpoint of quality, etc., by providing the low flat portion 3 at the end thereof, the insulation coating 13 can be removed and the terminal can be It is possible to easily perform processing necessary for connection with an external member such as a connector or the like.

In the insulated wire 1 according to the present embodiment, the material and wire diameter of the wire 12 constituting the conductor 11, and the cross-sectional area of the conductor are not particularly limited. However, it is preferable to use the conductor 11 having a relatively large conductor cross-sectional area from the viewpoint of improving the space-saving effect of the flat portion 20 and improving the workability of the low-flat portion 30 . From this point of view, as the material of the conductor 11, it is preferable to use aluminum or an aluminum alloy, which often has a large conductor cross-sectional area because of its low conductivity compared to copper and copper alloys. Moreover, the cross-sectional area of the conductor is preferably 10 mm ² or more, more preferably 50 mm ² or more, or 100 mm ² or more. As an outer diameter of the wire 12 constituting the conductor 11, a range of 0.3 mm or more and 1.0 mm or less can be exemplified.

The insulated wire 1 according to the present embodiment may be used alone or as a constituent member of the wire harness according to the embodiment of the present disclosure. A wire harness according to an embodiment of the present disclosure includes the insulated wire 1 according to the above embodiment. The wire harness may include a plurality of the insulated wires 1 described above, or may include other types of insulated wires in addition to the insulated wires 1 described above. In a wire harness including a plurality of insulated wires, the plurality of insulated wires are often connected to a common connector at the end portion. In this case, if the terminal of the insulated wire includes a flat shape, the entire connector must be wide to match the flat shape, and a large space may be required for arranging the connector. However, if a wire harness is configured using the insulated wire 1 according to the present embodiment in which the low-flat portion 30 is formed at the terminal portion, excessive widening of the connector can be avoided.

<Comparison between the flat part and the low flat part>
The flat portion 20 and the low flat portion 30 of the insulated wire 1 according to this embodiment have differences in structure and characteristics in addition to the difference in flatness in the cross-sectional shape of the conductor 11 .

(1) Adhesion between Conductor and Insulating Coating In the insulated wire 1 according to the present embodiment, the adhesion between the conductor 11 and the insulating coating 13 is smaller in the flat portion 30 than in the flat portion 20 . Since the flat portion 20 has a large surface area due to its flat shape, the flat portion 20 comes into contact with the insulating coating 13 over a large area. Therefore, the adhesion force per unit length along the axial direction is increased between the conductor 11 and the insulating coating 13 . However, in the low-flat portion 30, since the cross-sectional flatness is low, the surface area of the conductor is smaller than that of the flat portion 20 having the same conductor cross-sectional area, and the contact area with the insulating coating 13 is smaller. Therefore, in the low flat portion 30 , the adhesion force per unit length along the axial direction between the conductor 11 and the insulating coating 13 is smaller than that in the flat portion 20 .

Further, when forming the low-flat portion 30 by deforming the raw material flat electric wire 9, the adhesion between the conductor 11 and the insulating coating 13 in the low-flat portion 30 tends to be further reduced. In the flat portion 20, the raw material flat electric wire 9 is kept in contact with the outer periphery of the conductor 11 by extrusion molding or the like, and the insulating coating 13 is formed. A significant adhesion force is generated. However, since the low flat portion 30 deforms the conductor 11 by applying the force F1 to the conductor 11 from the outside of the insulating coating 13 with respect to the raw flat wire 9, the application of the force F1 and the deformation of the conductor 11 cause the insulating coating to deform. Adhesion between 13 and conductor 11 is eliminated or reduced. Therefore, in the low flat portion 30 , the adhesion between the insulating coating 13 and the conductor 11 tends to be significantly smaller than in the flat portion 20 .

In the low-flat portion 30, the adhesive force between the conductor 11 and the insulation coating 13 is reduced, so that the insulation coating 13 is removed in addition to the effect of the shape itself that the flatness is low as described above. The ease of processing of the low flat portion 30 is improved. This is because the insulating coating 13 exerts only a low adhesion force to the conductor 11, so that only a small force is required to peel and remove the insulating coating 13 from the outer periphery of the conductor 11 at the low flat portion 30. From the viewpoint of enhancing the effect of improving the peelability of the insulating coating 13, it is preferable that the adhesion force in the low flat portion 30 is small. 20% or more, preferably 30% or more. That is, where A1 is the adhesion force of the flat portion 20 and A2 is the adhesion force of the low flat portion 20, the adhesion force difference rate ΔA expressed by the following formula (1) is ΔA≦−5%, further ΔA≦− 10%, ΔA≦−20%, and ΔA≦−30%.
ΔA=(A2-A1)/A1 (1)
From the viewpoint of improving the peelability of the insulating coating 13, there is no particular lower limit for the adhesion force of the low flat portion 30, but from the viewpoint of preventing misalignment of the insulating coating 13 with respect to the conductor 11, for example, the adhesion force difference rate is within the ranges of ΔA≧−90% and ΔA≧−80%.

The low flat portion 30 enhances the peelability of the insulating coating 13 due to the low adhesion between the conductor 11 and the insulating coating 13 . is in close contact with the conductor 11, the displacement of the insulating coating 13 with respect to the conductor 11 is suppressed. In addition, when the conductor 11 is energized and the conductor 11 generates heat, the heat is efficiently transmitted to the edge coating 13 without passing through a layer of air at the place where the insulating coating 13 and the conductor 11 are in close contact with each other. high heat dissipation in the flat portion 20 is ensured. The effects of suppressing the displacement and improving the heat dissipation in the flat portion 20 are exhibited as the characteristics of the insulated wire 1 as a whole.

The adhesion between the conductor 11 and the insulation coating 13 can be evaluated by a pull-out test. As a specific test method, for example, a portion containing only the flat portion 20 or a portion containing only the low flat portion 30 is cut out from the insulated wire 1, and the insulating coating 13 is applied over a region of a predetermined length at the end. Peel off to expose conductor 11 . Then, the exposed conductor 11 is inserted into the through-hole having the same shape as the outer shape of the conductor 11 , and the conductor 11 is pulled at a predetermined speed to pull the conductor 11 out of the insulating coating 13 . The load required for pulling out is measured with a load cell or the like, and the maximum load is taken as the adhesion force of the insulating coating 13 to the conductor 11 . Then, the flat portion 20 and the low flat portion 30 cut to the same length may be compared with each other in the measured adhesion force.

(2) Distribution of voids In the cross section of the insulated wire 1 according to this embodiment, there is also a difference in the distribution of voids between the flat portion 20 and the low flat portion 30 in the region surrounded by the insulating coating 13 . In the insulated wire 1 according to this embodiment, the low flat portion 30 tends to have a higher porosity than the flat portion 20 . Here, the porosity refers to the ratio of the area of voids not occupied by the wires 12 to the area of the region surrounded by the inner periphery of the insulating coating 13 in the cross section of the insulated wire 1 .

The fact that the porosity of the low flat portion 30 tends to increase is related to the method of forming the low flat portion 30 . When the low flat portion 30 is formed by applying a force F1 from the outside of the raw material flat wire 9, the conductor 11 is deformed in the cross section of the insulated wire 1, and the shape of the insulating coating 13 is also changed in the direction of decreasing flatness. Although it changes, the inner peripheral length of the insulating coating 13 does not substantially change. If the inner peripheral length of the insulating coating 13 is the same, the area of the region surrounded by the inner periphery of the insulating coating 13 increases as the insulating coating 13 deforms into a shape with a lower flatness. At this time, since the area occupied by the wires 12 does not change in the region surrounded by the inner circumference of the insulating coating 13, the area of the voids not occupied by the wires 12 increases, and the porosity increases.

Since the force F1 is applied to the conductor 11 from the outside of the insulating coating 13 when forming the low flat portion 30 , a gap is likely to be formed between the outer periphery of the conductor 11 and the inner periphery of the insulating coating 13 . The formation of the gap between the conductor 11 and the insulation coating 13 also contributes to the reduction of adhesion between the conductor 11 and the insulation coating 13 . In particular, the force F1 for deforming the conductor 11 is applied from the outer side to the inner side in the width direction, and the dimension of the conductor 11 is compressed in the width direction. Gaps are likely to be unevenly distributed in the outer region in the equivalent direction. That is, in the width direction outer conductor region Rw corresponding to the outer region of the conductor 11 along the width equivalent direction (y direction), the height direction outer conductor region corresponding to the outer region of the conductor 11 along the height equivalent direction (z direction) A larger void is more likely to be formed than in the region Rh. As a result, the distance between the conductor 11 and the inner peripheral surface of the insulating coating 13 tends to be larger in the width direction outer conductor region Rw than in the height direction outer conductor region Rh, and between the conductor 11 and the insulating coating 13 is likely to be smaller in the width equivalent direction than in the height equivalent direction. Note that, not only in the low flat portion 30 but also in the boundary portion between the low flat portion 30 and the flat portion 20, uneven distribution of voids in the width direction outer conductor region Rw may occur.

The increased porosity in the low flat portion 30 not only reduces the adhesion between the conductor 11 and the insulating coating 13, but also increases the bending flexibility of the insulated wire 1 in the low flat portion 30. also have an effect. This is because, when the conductor 11 is bent, the flexible bending of the insulated wire 1 is assisted by the movement of the wire 12 into the gap. Gaps formed between the conductor 11 and the insulating coating 13, such as the width direction outside conductor region Rw, also have an effect of improving flexibility. , which is particularly effective in improving flexibility. Therefore, from the viewpoint of increasing the bending flexibility of the low flat portion 30, in the low flat portion 30, not only the gap in the entire area surrounded by the inner circumference of the insulating coating 13 but also the gap in the area inside the conductor 11 , the porosity is preferably larger than that of the flat portion 20 .

A specific porosity in the low flat portion 30 is not particularly limited. However, it is preferable that the porosity of the low flat portion 30 is 5% or more, further 10% or more, 20% or more, 30% or more, or 45% or more higher than that of the flat portion 20 . That is, when the porosity in the flat portion 20 is V1 (%) and the porosity in the low flat portion 30 is V2 (%), the porosity difference rate ΔV expressed by the following formula (2) is ΔV≧+5%, Further, it is preferable that ΔV≧+10%, ΔV≧+20%, ΔV≧+30%, and ΔV≧+45%.
ΔV=(V2−V1)/V1 (2)
Moreover, the value of the porosity (V2) in the low-flat portion 30 is preferably 30% or more, further 35% or more, or 40% or more. Then, in the low-flat portion 30, it becomes easy to reduce the adhesion force between the insulating coating 13 and the conductor, and it becomes easy to secure high flexibility. Also in the flat portion 20, the porosity (V1) of the flat portion 20 is preferably 10% or more, more preferably 20% or more, from the viewpoint of ensuring bending flexibility in the height equivalent direction (z direction). . From the viewpoint of flexibility, there is no particular upper limit to the porosity (V1, V2). , should be approximately 50% or less.

As described above, when the low flat portion 30 is formed by applying the force F1 to the raw material flat wire 9 to deform the conductor 11, the length of the inner circumference (inner circumference length) of the insulating coating 13 is The porosity of the low-flat portion 30 increases due to the increase in the area associated with the low-flatness of the region surrounded by the inner periphery of the insulating coating 13, which remains almost unchanged. From the viewpoint of enhancing the effect of increasing the porosity in the low flat portion 30 by this mechanism, the amount of change in the inner peripheral length of the insulating coating 13 accompanying the formation of the low flat portion 30, that is, the insulation between the flat portion 20 and the low flat portion 30 It is preferable that the difference in inner circumference length of the coating 13 is small. For example, the difference in inner circumference length of the insulating coating 13 between the flat portion 20 and the low flat portion 30 is preferably 5% or less with respect to the inner circumference length of the insulating coating 13 in the flat portion 20 . That is, the inner peripheral length of the insulating coating 13 in the flat portion 20 is D1, and the inner peripheral length of the insulating coating 13 in the low flat portion 30 is D2. |≤5%. Further, it is preferable that |ΔD|≦2%.
ΔD=(D2-D1)/D1 (3)

In addition, from the viewpoint of enhancing the effect of increasing the porosity in the low flat portion 30 by the above mechanism, the area (inner area) of the region surrounded by the inner circumference of the insulating coating 13 is greatly increased along with the formation of the low flat portion 30. preferably. That is, it is preferable that the inner area of the low flat portion 30 is larger than that of the flat portion 20 . For example, the inner area of the low flat portion 30 may be 30% or more, or preferably 50% or more larger than that of the flat portion 20 . That is, assuming that the inner area of the flat portion 20 is S1 and the inner area of the low flat portion 30 is S2, the inner area difference rate ΔS expressed by the following formula (4) is ΔS≧+10%, or further ΔS≧+20%. It should be above.
ΔS=(S2-S1)/S1 (4)

(3) Deformation of wire When manufacturing the insulated wire 1 according to the present embodiment by applying a force F1 from the width direction to the raw material flat wire 9 to form the low flat portion 30, Corresponding to the manufacturing method, in the flat portion 20 and the low flat portion 30, the deformation rate of the wire 12 in the cross section tends to be unevenly distributed. Here, the deformation rate of the wire 12 is an index indicating how much the wire 12 has a cross-sectional shape that deviates from a circular shape. , the deformation rate increases.

Specifically, as shown in FIGS. 2A and 2B , in both the flat portion 20 and the low flat portion 30, of the outer peripheral portion facing the outer periphery of the conductor 11, along the width equivalent direction (y direction), the outer ( In the width direction end (e.g., region R2) corresponding to the region of both ends), the central portion (e.g., region R1) located inside the outer peripheral portion and the outer (both ends) region along the height equivalent direction (z direction). The deformation rate of the wire 12 tends to be smaller than at the ends in the height direction (for example, the region R3). In other words, in the flat portion 20 and the low flat portion 30, the wires 12 at the ends in the width direction are more likely to have a shape closer to a circle than the wires 12 at the central portion and the ends in the height direction.

As described above, when the insulated wire 1 according to the present embodiment is formed from the raw material flat electric wire 9 containing the flattened stranded conductor, the conductor 11 included in the raw material flat electric wire 9 is formed using a roller. It was deformed flat by applying a gentle force to the twisted wire. Due to this, as described in Patent Documents 3 to 5, the outer peripheral portion, particularly the width direction end portion, has a smaller wire deformation ratio than the central portion. When the insulated wire 1 according to the present embodiment is manufactured from the raw material flat electric wire 9 , the structure of the conductor 11 in the raw material flat electric wire 9 is inherited substantially as it is in the flat portion 20 . In the low-flat portion 30 as well, the outer shape of the conductor 11 as a whole is deformed into a shape with a low degree of flatness, but the shape of each wire 12 is substantially unchanged. Therefore, the distribution of the deformation rate of the wires 12 occurring in the raw material flat electric wire 9 is carried over to the low flat portion 30 almost as it is. Therefore, in the flat portion 20 and the low flat portion 30 of the insulated wire 1 according to the present embodiment, similarly to the raw material flat wire 9, the deformation rate of the wire 12 is smaller than the ends.

<Deformed form: A form in which the flattening direction of the flattened portion is changed>
In the above, the low flat portions 30 are formed at both ends of one insulated wire 1, and the flat portions 20 having a uniform shape are formed at positions sandwiched between the low flat portions 30. explained. However, the number and arrangement of the flattened portions 20 and the low flattened portions 30 are not limited thereto, and any number of them can be provided in any arrangement order. For example, as the flat portion 20, a plurality of regions with different flattening directions can be provided. The plurality of regions may be provided adjacent to each other or may be provided with the low flat portion 30 interposed therebetween.

As an example of providing a plurality of regions in the flat portion, in FIGS. 3A to 3C, the flat portion 20A is provided with a first region 21, a second region 22, and a third region 23 as a plurality of regions with different flattening directions. Insulated wire 1A is shown. These three regions 21 to 23 are continuously provided in this order along the axial direction of the insulated wire 1A. In addition, although illustration is omitted, along the axial direction of the insulated wire 1A, the insulating Both ends of the electric wire 1A are provided with low flat portions. In the flat portion 20A, the first region 21, the second region 22, and the third region 23 have different flattening directions. Here, the flat direction refers to the direction of the flat shape of the cross section, that is, the direction in which the flat shape extends in the width direction.

Specifically, the first region 21 and the third region 23 have oblong flat shapes with the flattened direction oriented in the y direction. On the other hand, the second region 22 has a vertically elongated flattened shape whose flattening direction is oriented in the z-direction. The regions 21-23 are directly adjacent to each other, except for regions that inevitably occur with abrupt changes in the flattening direction.

The flat part of the insulated wire does not show very high flexibility in the width direction of the flat shape (that is, the flat direction), making it difficult to bend the insulated wire. Easy to bend. In this way, the flat portion has anisotropic flexibility, and when there are a plurality of regions with different flattening directions as the flat portion, the direction in which the insulated wire is likely to bend in the plurality of regions is different. In the example shown in FIGS. 3A-3C, the horizontally elongated first region 21 and the third region 23 tend to bend in the vertical direction (z direction), while the vertically elongated second region 22 tends to bend in the horizontal direction (y direction). direction).

Thus, by providing a plurality of regions 21 to 23 with different flattening directions as the flattened portion 20A, each portion of the flattened portion 20A of the insulated wire 1A can be easily bent in different directions. By bending the insulated wire 1A in different directions in these regions 21 to 23, for applications that require bending into complicated shapes, such as three-dimensional routing and routing along articles with complicated shapes, The insulated wire 1A can be preferably used. In the insulated wire 1A, depending on the specific wiring route, a required number of flat-shaped regions with the height direction facing the direction to be bent may be formed at the position where the bend is to be formed. .

In each of the regions 21 to 23 of the flat portion 20A, the specific flattening direction may be appropriately determined according to the direction in which the insulated wire 1A should be bent, as described above, and the difference in flattening direction between adjacent regions , is not particularly limited. For example, if the difference in flattening direction between adjacent regions is set to 10° or more, it is possible to sufficiently obtain the effect of realizing bending in various directions by providing a plurality of regions with different flattening directions. . However, the greater the difference in the flattening direction between adjacent regions, the easier it is to bend into a complicated shape. For example, in the embodiment shown in FIGS. 3A-3C, the difference in the plane direction between the first region 21 and the second region 22 and between the second region 22 and the third region 23 are both 90°. Thus, in the flat portion 20A, it is preferable to set the difference in the flattening direction between adjacent regions to 45° or more, particularly 80° or more.

When a plurality of regions 21 to 23 with different flattening directions are provided in the flat portion 20A, if each of the plurality of regions 21 to 23 has a higher degree of flatness than the low flat portion, each region 21 to The specific flatness of 23 (the aspect ratio of the flat shape of the cross section) and the flatness relationship between those regions 21 to 23 are not particularly limited. However, in order to allow each of the regions 21 to 23 to exhibit the same degree of flexibility in the height direction of each flat shape and to bend the insulated wire 1A in the same degree of flexibility in each direction, It is preferable that the plurality of regions 21 to 23 with different flattening directions exhibit the same degree of flattening. For example, in the flat portion 20A, it is preferable that the aspect ratio of the cross-sectional shape of one region is used as a reference, and the aspect ratio of the cross-sectional shape of the adjacent region is 80% or more and 120% or less. In the illustrated form, the flatness of the three regions 21-23 is the same.

Thus, the insulated wire 1A having a plurality of regions 21 to 23 with different flattening directions as the flattened portion 20A is also the raw material obtained by deforming the conductor 11 into a flattened shape, similarly to the insulated wire 1 described in detail above. The flat electric wire 9 can be suitably manufactured by selectively applying a force to a required area to partially deform the flat electric wire 9 . At this time, one of the plurality of flattened regions having different flattening directions or a plurality of flattened regions having the same flattening direction is left without deforming the raw material flat electric wire 9 from the original flat shape. Just do it. On the other hand, by applying force from the outside to the inside along the width direction (y direction) of the raw material flat electric wire 9, the original raw material flat electric wire is applied to the necessary portions of the low flat portion and the flat portion 20A. 9 and a region having a different flattening direction may be formed. At this time, a larger force is applied to a portion where a flat region having a different flattening direction from the original flat electric wire 9 is formed than at a portion where a low flat portion is formed, and the raw material flat electric wire 9 is moved from its original state to its flattened direction. It is greatly deformed until the state changes. When manufacturing the insulated wire 1A shown in FIGS. 3A to 3C, for example, the flattening direction of the raw flat wire 9 is oriented in the y direction, and in the middle of the axial direction of the raw flat wire 9, along the width direction (y direction) The second region 22 can be formed by applying a force from the outside to the inside of the cross section and changing the cross-sectional shape from a horizontally long state to a vertically long state. On the other hand, the first region 21 and the third region 23 can be formed by leaving the oblong flat shape of the raw material flat electric wire 9 unchanged at both sides of the second region 22 in the axial direction.

<Another embodiment>
In the insulated wire 1 according to the embodiment described above, by processing the raw material flat wire 9 including the flat conductor 11, the low flat portion 30 is formed in a part of the region, and the other region is is left as the flat portion 20, the flat portion 20 and the low flat portion 30 coexist. However, an insulated wire in which flat portions and low flat portions coexist can be produced by another method. An insulated wire 1' formed by another method will be briefly described below. In the following, descriptions of the same configurations as those of the above-described embodiment are omitted, and the description will focus on points that differ from the above.

An insulated wire 1' according to this alternative embodiment can be manufactured using a raw low-flat wire 9', as shown in FIG. Here, the raw material low-flat electric wire 9' is an insulated electric wire 1' in which the outer periphery of a conductor 11 in which a plurality of wires 12 are twisted is covered with an insulating coating 13, and the cross section of the conductor 11 is approximately It has an outer shape with low flatness, such as a circular shape. For example, a general-purpose round electric wire can be used as it is as the raw material low-flat electric wire 9'.

A flat portion 20 ′ is formed by increasing the flatness of the conductor 11 by applying a compressive force F<b>2 to the raw material low-flat electric wire 9 ′ from the directions facing each other in some regions. A region other than the flat portion 20' is left as a low flat portion 30'. Thereby, an insulated wire 1' having a flat portion 20' and a low flat portion 30' can be manufactured. That is, in the insulated wire 1 according to the embodiment described above, the low flat portion 30 is formed by processing the raw material flat wire 9, and the remaining portion is the flat portion 20. In the insulated wire 1' according to the embodiment, a flat portion 20' is formed by processing a raw material low-flat electric wire 9', and the remaining portion is a low-flat portion 30'.

In the insulated wire 1' according to this other embodiment, similarly to the insulated wire 1 described above, the flat portion 20' is in contact with the conductor 11 over a wider area than the low flat portion 30'. Therefore, the adhesion force between the conductor 11 and the insulating coating 13 is smaller in the low flat portion 30' than in the flat portion 20'. Therefore, by providing the low-flatness portion 30' at the terminal portion of the insulated wire 1' or the like, the adhesive force between the conductor 11 and the insulation coating 13 can be improved in combination with the effect of the low flatness of the outer shape itself. Due to the effect of the small size, the processing of the insulated wire 1' that involves the removal of the insulation coating 13 can be easily performed in the low flat portion 30'. Also in this embodiment, for example, the adhesion force in the low flat portion 30′ can be reduced by 20% or more, further 30% or more in comparison with the adhesion force in the flat portion 20′ (ΔA≦−20 %, or even ΔA≦−30%).

However, in the insulated wire 1' according to this other embodiment, unlike the insulated wire 1 described above, the low flat portion 30' is more It is difficult to form a state with a large porosity. Further, when the raw material low-flat electric wire 9' is compressed into a flat shape, the inner peripheral length of the insulating coating 13 may be stretched as the flatness increases. By stretching the inner peripheral length of the insulating coating 13, the adhesion between the conductor 11 and the insulating coating 13 is strengthened at the widthwise outer portion, and the adhesion force is greater in the flat portion 20' than in the low flat portion 30'. In order to prevent excessive load from being applied to the insulating coating 13 when the inner peripheral length of the insulating coating 13 is stretched, it is preferable to use a material that has a relatively low tensile modulus and is easily stretched as the insulating coating 13. Furthermore, in the insulated wire 1' of this form, the conductor 11 is deformed into the low-flat portion 30' both during the production of the raw low-flat wire 9' and during processing from the raw low-flat wire 9'. No force can be applied. Therefore, in the cross section of the low flat portion 30', the wire 12 maintains a shape close to a circular cross section with a small deformation rate regardless of the position.

An insulated wire 1A including a plurality of regions 21 to 23 with different flattening directions can be manufactured as a flat portion 20A as shown in FIGS. . In this case, when forming the flat portion 20A by applying force to the raw material low-flat electric wire 9′, by setting a plurality of regions with different directions of applying force, the plurality of regions 21 to 23 with different flattening directions are set. can be formed. When manufacturing the insulated wire 1A having the shape shown in FIGS. 3A to 3C, the raw material low-flat wire 9′ is placed along the z direction at the positions where the horizontally long first region 21 and the third region 23 are to be formed. A compressing force is applied, and a compressing force is applied along the y-direction to the position where the elongated second region 22 is to be formed.

Examples are shown below. However, the present invention is not limited to these examples. Here, for two types of insulated wires, the states were compared between the flat portion and the low flat portion.

(Sample preparation)
(1) Sample 1
First, a raw material flat electric wire was produced. First, a stranded wire having a substantially circular cross section was prepared by twisting aluminum alloy strands, and a conductor was produced by compressing the stranded wire into a flat shape with a roller. The stranded wire used had a conductor cross-sectional area of 130 mm ² and a wire diameter of 0.42 mm. The aspect ratio w/h of the flat shape was about 3. An insulating coating was formed on the outer periphery of the produced conductor by extrusion molding to obtain a raw material flat electric wire. Crosslinked polyethylene was used as a constituent material of the insulating coating, and the thickness of the insulating coating was set to 2 mm.

A low-flat portion was formed by applying a force directed from the outside in the width direction of the flat shape to the inside in some regions of the raw material flat electric wire to reduce the flatness of the flat shape of the conductor. . Areas where no force was applied were left as flattened areas. The aspect ratio w/h of the conductor in the low flat portion was about 1. Formation of the low flat portion was performed by press working at room temperature.

(2) Sample 2
First, a raw low-flat electric wire was produced. First, a stranded wire having a substantially circular cross section was prepared by twisting aluminum alloy strands. As the stranded wire, a wire having a conductor cross-sectional area of 60 mm ² and a wire diameter of 0.32 mm was used. An insulating coating was formed on the outer periphery of the produced conductor by extrusion molding to obtain a raw material low-flat electric wire. Polyvinyl chloride was used as a constituent material of the insulation coating, and the thickness of the insulation coating was 2 mm.

A flattened portion was formed by applying pinching force from opposite directions to the low-raw material flat wire to compress the conductor and increase the degree of flatness in some regions. Areas where no force was applied were left as low flattened areas. The aspect ratio w/h of the conductor in the flat portion was about 3. The flat portion was formed by press working at room temperature.

(Evaluation method)
Cross-sectional observation was performed for each of the flat portion and the low flat portion of Samples 1 and 2 produced above. Each sample was embedded and fixed in acrylic resin. Then, cross-sectional samples were obtained by cutting the insulated wire perpendicularly to the axial direction at each of the flat portion and the low flat portion. The obtained cross-sectional sample was observed with a microscope, and image analysis was performed on the observed image to evaluate the void area, inner area, porosity, and inner peripheral length of the region inside the insulating coating. For the low flat portion of sample 1 and the flat portion of sample 2, cross-sectional samples were prepared at three positions 1 to 3 and evaluated, and the obtained values were averaged at the three positions.

Separately, for the insulated wires of Samples 1 and 2, the adhesion between the conductor and the insulation coating was evaluated in each of the flat portion and the low flat portion. A region containing only the flat portion or only the low flat portion of each sample was cut to 70 mm, and the insulating coating was peeled off in a region of 25 mm from the end to expose the conductor. A through-hole having the same shape as the outer shape of the conductor was formed in the metal plate, and the exposed conductor was inserted through the through-hole. Then, the conductor was pulled at a speed of 250 mm/sec to pull the conductor out of the insulating coating. The load required for drawing was measured with a load cell, and the maximum load was defined as the adhesion of the insulating coating to the conductor.

(Evaluation results)
6A and 6B show the cross-sectional images at each position, the evaluation results of the state of the cross-sections, and the measurement results of the adhesion force for the samples 1 and 2, respectively. In the cross-sectional images, the scales of the flat portion and the low-flat portion are appropriately changed. Also shown in the table is the rate of difference between the flattened portion and the low flattened portion for each measured value. Here, the rate of difference indicates how much the value of the low flat portion changes with respect to the value of the flat portion. That is, the difference rate is expressed by the following formula (5).
Differential rate = (low flat portion value - flat portion value) / flat portion value x 100% (5)
When cross-sections are evaluated at multiple positions, the average value is used to calculate the differential ratio. In FIGS. 6A and 6B, the values used to calculate the difference rate and the calculated difference rate are displayed in bold.

According to the cross-sectional image of Sample 1 shown in FIG. 6A, it is confirmed that the low flat portion formed by applying force to the raw material flat electric wire has a shape with a lower degree of flatness than the flat portion. Comparing the measurement results of the adhesion force between the flat portion and the low flat portion, the low flat portion has a smaller value, and the difference rate is ΔA≦−30%. In other words, the adhesion between the insulating coating and the conductor is reduced by 30% or more due to the low flatness.

Focusing on the distribution of voids not occupied by wires in the cross-sectional image, first, in the flat portion, the insulating coating adheres to the outer periphery of the conductor, and the voids between the conductor and the insulating coating are very small. On the other hand, in the low-flat part, a clear air gap occurs between the conductor and the insulation coating. Furthermore, the gaps are unevenly distributed in the width equivalent direction (horizontal direction of the image). The uneven distribution of voids is particularly noticeable at positions 2 and 3. Furthermore, it can be seen that the gap in the region between the strands inside the conductor is also larger in the low flat portion than in the flat portion. From these facts, it can be seen that the voids formed in the region surrounded by the inner circumference of the insulating coating are larger in the low flat portion than in the flat portion. These results are more clearly shown by the fact that the measured values of the void area and the porosity are larger in the low flattened portion than in the flattened portion, and the difference value between them is a positive value. . Regarding the porosity, the value of the flat portion is larger than that of the flat portion by 50% or more (ΔV≧+50%).

The inner peripheral length of the insulating coating does not change between the flat portion and the low flat portion (ΔD=0%). On the other hand, the inner area of the insulating coating is 20% or more larger in the low flat portion than in the flat portion (ΔS≧+20%).

From the above results, when a force is applied to the raw material flat wire from the outside in the width direction to form a low flat portion, the conductor deforms into a low flat shape inside the space where the change in the inner circumference length of the insulation coating is restricted. By doing so, it is interpreted that the area of the space surrounded by the inner peripheral surface of the insulating coating increases, thereby increasing the porosity. It is believed that the increase in porosity, particularly the formation of voids in the region between the conductor and the insulation coating, reduces the adhesion between the insulation coating and the conductor.

Next, according to the cross-sectional image of sample 2 shown in FIG. 6B , the low flat portion, which retains the structure of the raw material low-flat electric wire, has a flatter degree than the flat portion formed by applying a compressive force to the raw low-flat electric wire. It is confirmed that it has a low profile. Comparing the measurement results of the adhesion force between the flat portion and the low flat portion, the low flat portion has a smaller value, and the difference ratio is ΔA≦−30%. That is, the compression of the raw material low-flat wire increases the adhesion between the insulating coating and the conductor, and the low-flat portion remains at a state where the adhesion is 30% or more lower than that of the flat portion formed through compression.

Focusing on the distribution of voids in the cross-sectional image, there are almost no voids formed between the conductor and the insulating coating in both the flat portion and the low flat portion. It can be seen that the gap between the wires inside the conductor is larger in the flat part than in the low flat part. That is, it can be seen that the gap formed in the region surrounded by the inner circumference of the insulating coating is larger in the flat portion than in the low flat portion. These results are more clearly shown by the fact that the measured values of void area and void ratio are larger in the flattened portion than in the low flattened portion, and the difference rate is also negative. This result implies that the compression from the low profile shape to the flat shape increases the void inside the conductor.

In sample 1, the inner circumference length of the insulating coating did not change through the formation of the low flat portion due to the application of force. The length is longer (difference ratio ΔD≦0), and the inner peripheral length of the insulating coating is extended through the formation of a flat portion due to the application of force. This phenomenon is considered to be due to the extension of the insulation coating along with the deformation of the conductor when the conductor is compressed by the application of force.

Although the embodiments of the present disclosure have been described in detail above, the present invention is by no means limited to the above embodiments, and various modifications are possible without departing from the gist of the present invention.

1, 1', 1A Insulated wire 11 Conductor 12 Wire 13 Insulation coating 20, 20', 20A Flat portion 21 First region 22 Second region 23 Third region 30, 30' Low flat portion 9 Raw flat wire 9′ Raw material low-flat electric wire h Conductor height w Conductor width x Insulated wire axial direction y Width equivalent direction z Height equivalent direction F1 Force F2 Force R1 Central region R2 Width direction end region R3 Height direction Edge region Rh Height direction outside conductor region Rw Width direction outside conductor region

Claims (11)

a conductor in which a plurality of strands are twisted together;
An insulated wire having an insulating coating that covers the outer periphery of the conductor,
Each of the wires constituting the conductor and the insulating coating are connected to each other to have a flat portion and a low flat portion along the axial direction,
The outer shape of the conductor in a cross section orthogonal to the axial direction of the insulated wire has a flattened shape at the flattened portion, and a flatter shape at the low flattened portion than the flattened portion,
The insulated wire, wherein adhesion between the conductor and the insulating coating is smaller in the low flat portion than in the flat portion. 2. The insulated wire according to claim 1, wherein the adhesion between said conductor and said insulating coating is 20% or more smaller in said low flat portion than in said flat portion. 2. A porosity, which is a ratio of voids not occupied by wires, in the area of the region surrounded by the inner circumference of the insulating coating in the cross section, is larger in the low flat portion than in the flat portion. The insulated wire according to claim 2. The insulated wire according to claim 3, wherein the porosity in the cross section is 20% or more larger in the low flat portion than in the flat portion. In the cross section of the low-flat portion, regions outside the conductor along directions corresponding to the width direction and the height direction of the flat shape are defined as a width direction outside conductor region and a height direction outside conductor region, respectively. ,
5 . The insulated wire according to claim 1 , wherein in the width direction outside conductor region, a gap larger than that in the height direction outside conductor region is formed between the conductor and the insulation coating. In the cross section, the difference in length of the inner circumference of the insulating coating between the flat portion and the low flat portion is 5% or less of the length of the inner circumference of the insulating coating in the flat portion. The insulated wire according to any one of claims 1 to 5. The insulated wire according to any one of claims 1 to 6, wherein the flattened portion has a plurality of regions with different flattened directions. The insulated wire according to any one of claims 1 to 7, wherein the insulated wire has the low flat portion on at least one side of the flat portion along the axial direction. After compressing a conductor in which a plurality of wires are twisted together into a flat shape and covering the outer periphery with an insulating coating to make an insulated wire,
A low-flat portion is formed by reducing the flatness of the conductor by applying a force from the outside in the width direction toward the inside of the flat shape in a partial region along the axial direction of the insulated wire. ,
An insulated wire manufactured by leaving a flat portion other than the low flat portion. After covering the outer periphery of the conductor in which a plurality of wires are twisted together with an insulating coating to form an insulated wire,
In some regions along the axial direction of the insulated wire, a flat portion is formed by increasing the flatness of the conductor by applying a force that compresses the insulated wire from mutually opposing directions, and
An insulated wire manufactured by leaving a region other than the flattened portion as a low flattened portion. A wire harness comprising the insulated wire according to any one of claims 1 to 10.

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