JP2018045855A - Flat cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flat cable having light weight and also excellent mechanical characteristics.SOLUTION: The flat cable is provided, comprising: a plurality of insulated wires each of which comprises a conductor and an insulating coating covering the conductor; and a sheath part integrally covering the plurality of insulated wires while the insulated wires are arranged side by side. In the flat cable, a conductor of at least one insulated wire of the plurality of insulated wires is a metal-coated wire that comprises a center element wire composed of an aluminum alloy and a metal layer composed of copper or copper alloy that covers the center element wire, and the tensile strength of the metal-coated wire is 130 MPa or larger and 250 MPa or smaller, and the elongation at break of the metal-coated wire is 6% or larger.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a flat cable.

  As a cable used for indoor wiring of a house or the like, there is a flat vinyl insulated vinyl sheath cable (VVF). As shown in FIG. 1 of Patent Document 1, the VVF includes a plurality of insulated wires in which the outer periphery of a conductor (conducting wire) is covered with an insulation coating of polyvinyl chloride, and a poly which integrally covers the plurality of insulated wires in a side-by-side state. A flat cable having a vinyl chloride sheath. Conventionally, a copper wire has been used as a conductor of an insulated wire (specification [0025] of Patent Document 1).

JP 2012-038648 A

Weight reduction is desired for flat cables such as VVF.
Since the flat cable using the above-mentioned insulated wire conductor as a copper wire is heavy, it is desired to reduce the burden on the operator from the transportation to the laying. For example, when laying indoor wiring in a building such as a house or building, it is carried into a laying site from a transport vehicle, a cable wound in a coil is drawn out to remove bending wrinkles, wiring in the building, cable The operator performs operations such as attaching the terminal to the end and connecting the terminal to the connector. In these operations, a heavy load is imposed on the operator with a heavy flat cable.

It is also desirable to satisfy predetermined mechanical characteristics while being lightweight.
For example, when a flat cable is used for indoor wiring, the flat cable is flexible enough to be bent by an operator, and is momentarily pulled by a large force or sudden impact is applied. It is desirable to have strength and toughness that does not cause disconnection in the event of breakage.

  Therefore, an object is to provide a flat cable that is lightweight and excellent in mechanical characteristics.

A flat cable according to an aspect of the present disclosure is provided.
A plurality of insulated wires comprising a conductor and an insulating coating covering the conductor;
A sheath portion that integrally covers the plurality of insulated wires side by side,
Among the plurality of insulated wires, the conductor of at least one insulated wire is:
A metal-coated wire comprising a central strand composed of an aluminum alloy and a metal layer composed of copper or a copper alloy covering the central strand;
The tensile strength of the metal-coated wire is 130 MPa or more and 250 MPa or less, and the breaking elongation of the metal-coated wire is 6% or more.

  The flat cable described above is lightweight and has excellent mechanical properties.

1 is a schematic cross-sectional view showing a flat cable according to Embodiment 1. FIG.

[Description of Embodiment of the Present Invention]
First, embodiments of the present invention will be listed and described.
(1) A flat cable according to an aspect of the present invention is:
A plurality of insulated wires comprising a conductor and an insulating coating covering the conductor;
A sheath portion that integrally covers the plurality of insulated wires side by side,
Among the plurality of insulated wires, the conductor of at least one insulated wire is:
A metal-coated wire comprising a central strand composed of an aluminum alloy and a metal layer composed of copper or a copper alloy covering the central strand;
The tensile strength of the metal-coated wire is 130 MPa or more and 250 MPa or less, and the breaking elongation of the metal-coated wire is 6% or more.

  In the above flat cable, a conductor of at least one insulated wire among a plurality of insulated wires includes a central strand made of an aluminum alloy (hereinafter sometimes referred to as an Al alloy) that is lighter than copper. Therefore, the flat cable is lighter than the case where the above-described copper conductor is provided. If it is a flat cable including a central strand made of an Al alloy, the conductors of all insulated wires are lighter. Moreover, the tensile strength and breaking elongation of this lightweight conductor satisfy a specific range. Therefore, the above flat cable is excellent in mechanical characteristics. Specifically, the above-described flat cable is flexible enough to be bent by an operator, but is not easily broken even when it is pulled with a large force or a sudden impact is applied. Has a certain degree of strength and toughness. Therefore, the above-described flat cable is lightweight and excellent in mechanical properties, and can be suitably used for indoor wiring that requires the above-mentioned flexibility, strength, toughness, impact resistance, etc. This contributes to reducing the burden on the user.

The above flat cable is based on the following knowledge.
The present inventors consider the weight reduction of flat cables used for indoor wiring and the like and the required mechanical properties (the above-mentioned flexibility, strength, toughness, impact resistance, etc.) It was studied that the conductors of these were made of Al alloy. Here, when laying indoor wiring, there is a possibility that a large stress, steep repeated bending, impact, or the like may be locally applied to the flat cable under the following conditions. This situation means that a cable wound in a coil shape is pulled out with a large momentary momentary force, or the pulled-out cable is swung like a wave to remove curl, or when a terminal is being installed or connected to a connector. For example, the cable may be dropped during work. Pure aluminum is soft and easy to bend but has low strength. Therefore, if the conductor of the insulated wire is a pure aluminum wire, there is a possibility of disconnection under the above situation. If alloyed, strength such as tensile strength can be increased, but it cannot be said that the above requirements such as flexibility, toughness and impact resistance are sufficiently satisfied. On the other hand, by setting both the tensile strength and the elongation at break to a specific range, while having the above-described flexibility, it is excellent in strength, toughness, etc., and can be hardly broken during the above-described laying operation. , And got the knowledge.
Also, in order to use a metal-coated wire having a metal layer made of copper or copper alloy on the surface of the Al alloy wire as a conductor, the conductor metal layer and the terminal are in a state where the terminal is attached to the conductor at the cable end. Contact resistance can be lowered by contact. Here, when the conductor of the insulated wire is an Al wire or an Al alloy wire, when the insulation coating is removed at the end of the cable and the terminal is attached to the conductor, the conductor surface is exposed to the atmosphere, so that the Al wire or Al A natural oxide film is formed on the surface of the alloy wire. Therefore, the natural oxide film, which is an electrical insulating material, is interposed between the conductor and the terminal, which can increase the connection resistance. On the other hand, if the metal-coated wire is a conductor, the surface of the Al alloy wire is not exposed to the atmosphere when connecting the above-mentioned terminals, and an increase in the connection resistance between the cable and the terminal is suppressed, and electrical connection is made. Obtained that it can be performed well. In addition, when the terminal is a widely used copper or copper alloy terminal, the contact point with the terminal in the cable can be a copper or copper alloy metal layer, thereby reducing the connection resistance. easy.

(2) As an example of the above flat cable,
The said aluminum alloy contains 0.005 mass% or more and 2.2 mass% or less of Fe, and the form whose remainder is Al and an unavoidable impurity is mentioned.

  The above form is excellent in strength by including Fe in a specific range, for example, can satisfy a tensile strength of 130 MPa or more, and is excellent in elongation by performing a softening treatment in the manufacturing process, for example, elongation at break of 6% The above can be satisfied. Therefore, the said form is lightweight and is excellent also in a mechanical characteristic. Moreover, since the said form contains Fe in a specific range, the fall of the electrical conductivity by Fe containing can be reduced, it can have high electrical conductivity, or the adhesive force with a terminal can be raised.

(3) As an example of the flat cable of (2) containing Fe in a specific range,
The aluminum alloy further includes one or more elements selected from Mg, Si, Cu, Zn, Ni, Mn, Ag, Cr, Zr, and Y in total of 0.005% by mass to 1.0% by mass. The form to contain below is mentioned.

  In addition to Fe, the above-mentioned form can further increase at least one of tensile strength and breaking elongation by including the listed elements in a specific range, and further decrease the conductivity due to the inclusion of these elements. Can be reduced. Therefore, the said form is lightweight, is excellent in mechanical characteristics, and is excellent also in electroconductivity.

(4) As an example of the above flat cable,
The form whose area ratio of the said metal layer in the cross section of the said metal-coated wire is 10% or more and 30% or less is mentioned.

  Since the said form is equipped with a metal layer in a specific range, the reduction effect of the connection resistance by provision of a metal layer and the effect of weight reduction by provision of Al alloy can be acquired favorably.

[Details of the embodiment of the present invention]
Hereinafter, a specific example of a flat cable according to an embodiment of the present invention will be described with reference to the drawings.
[Embodiment 1]
With reference to FIG. 1, the flat cable 1 of Embodiment 1 is demonstrated. FIG. 1 is a cross-sectional view of a flat cable 1 cut along a plane perpendicular to the longitudinal direction thereof. The flat cable 1 is integrally formed with a plurality of insulated wires 2 (two insulated wires 2A and 2B in FIG. 1) provided with a conductor 20 and an insulation coating 25 covering the conductor 20, and a plurality of insulated wires 2 arranged side by side. And a sheath portion 3 covering the surface. The flat cable 1 of the first embodiment is characterized in that the conductor 20 of at least one insulated wire 2 among the plurality of insulated wires 2 has a specific structure and satisfies specific characteristics. The conductor 20 having this specific structure is a metal-coated wire including a center wire 22 made of an aluminum alloy (Al alloy) and a metal layer 24 made of copper or a copper alloy covering the center wire 22. is there. The tensile strength of the metal-coated wire is 130 MPa or more and 250 MPa or less, and the breaking elongation of the metal-coated wire is 6% or more. Hereinafter, the flat cable 1 and the metal-coated wire will be described in order.

(Flat cable)
The flat cable 1 can typically take a basic structure of a known cable such as a 600 V vinyl insulated vinyl sheath cable (VVF), a 600 V polyethylene insulated polyethylene sheath cable (EEF), or the like. The flat cable 1 of this example includes two insulated wires 2A and 2B arranged in parallel, and a sheath portion 3 that collectively covers the outer periphery of both insulated wires 2A and 2B, and is a flat formed in a racetrack shape. Cable. The number of insulated wires 2 can be changed as appropriate, and can be three, or four or more.

Insulated wire Each insulated wire 2 includes a conductor 20 and an insulating coating 25, and is typically a round wire having a circular cross section. The constituent material and size of each insulated wire 2 are basically the same. The conductor 20 in this example is a single wire having a predetermined wire diameter, but is a stranded wire formed by twisting a plurality of strands such as seven stranded wires, or a compression formed by compressing a stranded wire into a predetermined shape and size. It can be a stranded wire or the like. At least one of the plurality of strands constituting the stranded wire is a metal-coated wire. When it is a stranded wire consisting of only a metal-coated wire, or a mixed stranded wire consisting of a metal-coated wire and one wire selected from a copper wire and a copper alloy wire, copper or a copper alloy is interposed between adjacent strands. , Good conduction between the strands. Further weight reduction can be achieved by using a mixed stranded wire of a metal-coated wire (eg, outer peripheral wire) and one wire (eg, center wire) selected from an aluminum wire and an aluminum alloy wire.

  The insulating coating 25 is made of a resin having insulating properties, flexibility, heat resistance, water resistance, etc., typically, polyvinyl chloride (PVC), polyethylene (PE), or the like. The insulating coating 25 is formed by extrusion coating on the conductor 20. The insulation coating 25 of each insulated wire 2 can be colored differently (for example, one is black and the other is white) so that an operator can visually identify each insulated wire 2. A known structure can be used as the basic structure of the insulated wire 2.

-Sheath part The sheath part 3 hold | maintains and protects the several insulated wires 2A and 2B integrally, and is formed in the thickness which has predetermined mechanical strength and electrical insulation performance. Insulated wires 2A and 2B are arranged in parallel, and melted resin (resin that becomes sheath portion 3 after solidification) is extruded and coated around these to form a sheath portion 3 by forming in a racetrack shape or the like. The The sheath portion 3 is made of a resin having insulating properties, flexibility, heat resistance, and water resistance, typically a resin such as PVC or PE described in the section of the insulating coating 25. Examples of other resins include foamed resins containing bubbles by mixing foaming agents with resins such as PVC and PE. The sheath part 3 can also be given an appropriate color (for example, gray).

(Metal-coated wire)
The metal-coated wire includes a central strand 22 made of an Al alloy and a metal layer 24 made of copper or a copper alloy, and the tensile strength and breaking elongation satisfy a specific range. Hereinafter, the center strand 22, the metal layer 24, and the characteristics will be described in order.

-Center strand The Al alloy which comprises the center strand 22 can be made into the various composition with which the tensile strength and breaking elongation of a metal-coated wire satisfy | fill a specific range. As an example, an Al alloy containing Fe in a specific range described later, an Al alloy including one or more elements selected from a specific element group described below in addition to Fe, an element having a crystal fine effect described later, and the like. Can be mentioned. Hereinafter, the additive elements will be described. The element content is set to a mass ratio (mass%) with the Al alloy as 100 mass%.

<Fe: 0.005% to 2.2%>
Fe can improve the strength of the Al alloy without causing much decrease in the conductivity of the Al alloy. Inclusion of 0.005% or more of Fe contributes to increasing the strength of the Al alloy, and the greater the amount of Fe, the easier it is to obtain a strength improvement effect. By including Fe in the range of 2.2% or less, there is little decrease in toughness and electrical conductivity, and it is easy to have high breaking elongation and high electrical conductivity, and it is easy to reduce disconnection at the time of wire drawing. Also excellent. Since the strength can be increased, it is easy to have a high strength even when subjected to a softening treatment. When Fe is contained in an amount of 0.2% or more, further 0.5% or more, 0.9% or more, 1.0% or more, or 1.05% or more, the strength is easily increased. When Fe is contained in the range of 2.0% or less, and further 1.8% or less, it tends to have high elongation at break and high electrical conductivity.

<Element group: One or more elements selected from Mg, Si, Cu, Zn, Ni, Mn, Ag, Cr, Zr, and Y in total 0.005% to 1.0%>
By including one element selected from the above element group, or two or more elements, an improvement in at least one characteristic such as strength, toughness, and impact resistance of the Al alloy can be expected. Although Mg has a large decrease in conductivity, the effect of improving strength is high. In particular, when Mg and Si are contained at the same time, the strength is easily increased. Although Mn, Ni, Zr, and Cr have a large decrease in electrical conductivity, the effect of improving the strength is high. Ag and Zn have a small decrease in conductivity and a certain degree of strength improvement effect. Cu has little decrease in conductivity and has an effect of improving strength. As described above, Si is contained at the same time as Mg, so that the effect of improving strength is high. Y has the effect of improving the strength while making the crystal grains fine. Examples of the content of each element include the following.
Mg: 0.05% to 0.5%, 0.05% to 0.4%, 0.1% to 0.4% Mn, Ni, Zr, Zn, Cr and Ag: 0 in total 0.005% or more and 0.2% or less, and in total 0.005% or more and 0.15% or less Cu: 0.01% or more and 0.5% or less, and further 0.05% or more and 0.4% or less Si: 0 .05% to 0.3%, Si: 0.05% to 0.2% Y: 0.01% to 0.5%, further 0.01% to 0.3% Mg, Cu When Zn, Ni, Mn, Ag, Cr, and Zr are contained in the above range, the strength is excellent, and the toughness and conductivity are reduced by reducing the toughness and conductivity, and disconnection is hardly caused. When Si is contained in the above range, the strength is excellent, and also the toughness and conductivity are reduced by reducing the decrease in toughness and conductivity. When Y is contained in the above range, the strength and toughness are excellent.

<Crystal refinement element: at least one of Ti of 0.01% or more and 0.05% or less and B of 0.001% or more and 0.005% or less>
When at least one of Ti of 100 ppm to 500 ppm and B of 10 ppm to 50 ppm are contained by mass ratio, it is easy to make Al alloy crystals fine at the time of casting. An Al alloy having a fine crystal structure tends to have high strength. Moreover, when at least one of Ti and B is contained in said range, the fall of electrical conductivity will be reduced and it will be excellent also in electroconductivity.

Specific examples of the composition of the Al alloy containing the above-described additive element include the following.
(1) Fe is contained in an amount of 0.005% to 2.2%, and the balance is Al and inevitable impurities. (2) Fe is 0.005% to 2.2%, Mg, Si, Cu, Zn , Ni, Mn, Ag, Cr, Zr, and Y containing a total of one or more elements selected from 0.005% to 1.0%, with the balance being Al and inevitable impurities (3) The above (1) or (2) further contains at least one of 0.01% to 0.05% Ti and 0.001% to 0.005% B.

Specific examples of the composition (2) include the following.
(2-1) Fe from 0.9% to 1.2%, Mg from 0.1% to 0.25% (2-2) Fe from 1.0% to 2.2%, Mg 0.05% or more and 0.5% or less, and one or more elements selected from Si, Mn, Ni, Zr, Zn, Cr, and Ag in total 0.005% or more and 0.2% or less (2- 3) Fe is 0.05% or more and 2.2% or less (further 0.1% or more, 0.5% or more, 1.0% or more), Cu is 0.01% or more and 0.5% or less (further 0 .02% or more, 0.05% or more)
(2-4) Fe of 1.0% to 2.2%, Cu of 0.05% to 0.5%, Mg of 0.1% to 0.5% and Si of 0.05% At least one (2-5) Fe of not less than 0.3% is not less than 0.005% and not more than 0.6%, Mg is not less than 0.2% and not more than 0.5%, Si is not less than 0.2% and not more than 0.00%. 35% or less, Cu 0.05% to 0.1%, Mn 0.005% to 0.1%, Y 0.01% to 0.5%

-Metal layer The metal layer 24 is comprised with copper or a copper alloy. The copper here is so-called pure copper containing 99.9% by mass or more of Cu. Since copper is generally softer than a copper alloy and excellent in conductivity, the metal-coated wire including the copper metal layer 24 is excellent in flexibility such as bending and easily has high conductivity. A copper alloy contains an additive element and the balance is composed of Cu and inevitable impurities. Examples of the additive element include one or more elements selected from Zn, Pb, Sn, Al, and Fe. The total content is, for example, about 0.1% by mass to 10% by mass. Since a copper alloy is generally superior in strength to pure copper, a metal-coated wire including the metal layer 24 of the copper alloy is excellent in strength.

  As the area ratio of the metal layer 24 in the cross section of the metal-coated wire is smaller, the weight can be reduced. The larger the area ratio of the metal layer 24, the better the conductivity, strength, toughness and the like. Considering the balance between weight reduction and good characteristics, the area ratio of the metal layer 24 is 10% to 50%, more preferably 10% to 40%, particularly preferably 10% to 30%, and more preferably 15% or more. It can be 30% or less, particularly 20% or more and 30% or less.

-Shape and size A typical metal-coated wire is a round wire having a circular cross section. In addition, examples of the metal-coated wire include curved lines such as an elliptical cross-sectional shape, and irregular lines such as a polygonal shape such as a rectangle or a hexagon. The wire diameter of the metal-coated wire (in the case of a deformed wire, the diameter of the envelope circle) can be appropriately selected within a range that satisfies a predetermined conductor diameter according to the application. For indoor wiring applications, the wire diameter is about 0.2 mm or more and 3.2 mm or less.

・ Characteristics Metal-coated wire has both high strength and high toughness, excellent impact resistance, and easy bending because its tensile strength satisfies both 130 MPa and 250 MPa and elongation at break of 6% or more. In addition, it is difficult to break even when subjected to a large stress momentarily, an impact, or repeated bending. In addition, because the tensile strength is high, it is excellent in rigidity, so that it can maintain a linear state after removal of the bending wrinkles, maintain its shape when it is bent locally and made into a predetermined shape, etc. Excellent shape retention. In order that the tensile strength and elongation at break satisfy the above ranges, the kind and amount of additive element of Al alloy or copper alloy, the area ratio of the metal layer 24, manufacturing conditions (drawing degree of the central strand 22, softening conditions, The formation conditions of the metal layer 24 and the like may be adjusted (this applies to the conductivity and 0.2% proof stress described later).

  The higher the tensile strength of the metal-coated wire is in the above range, the better the strength is, and the more difficult it is to break, and the lower the range is, the easier it is to increase elongation at break and electrical conductivity. The tensile strength can be 130 MPa or more and 200 MPa or less, further 140 MPa or more and 190 MPa or less, and 160 MPa or more and 180 MPa or less.

  The higher the breaking elongation of the metal-coated wire is in the above range, the better the flexibility and toughness, the easier it is to bend, and the more difficult it is to break, and the lower the range, the easier it is to increase the tensile strength. The elongation at break can be 8% or more, more preferably 10% or more, and 13% or more.

  Since the metal-coated wire constitutes the conductor 20, it is preferable that the conductivity is high, and it is preferably 65% IACS or more, more preferably 66% IACS or more, and 67% IACS or more.

  The metal-coated wire preferably has a high 0.2% proof stress. This is because when the tensile strength is the same, the higher the 0.2% proof stress, the better the adhesion to the terminal. The 0.2% yield strength of the metal-coated wire is preferably 80 MPa or more, more preferably 100 MPa or more, and further preferably 120 MPa or more.

[Flat cable manufacturing method]
The above-described flat cable 1 can be typically manufactured by arranging a plurality of insulated wires 2 side by side and forming the sheath portion 3 on the outer periphery thereof by extrusion or the like in this side-by-side state. The insulated wire 2 can be typically manufactured by forming the insulating coating 25 on the outer periphery of the conductor 20 by extrusion or the like. As a basic manufacturing method of the flat cable 1 and the insulated wire 2, a known manufacturing method can be used.

  The metal-coated wire constituting the conductor 20 can be manufactured by forming the metal layer 24 on the outer periphery of the central strand 22. A known method for producing a copper wire can be used as a basic method for producing a metal-coated wire. Typically, an Al alloy wire having a predetermined wire diameter is inserted and arranged in a pipe material made of copper or a copper alloy to form a composite material, and this composite material is subjected to wire drawing to produce an Al alloy wire and a copper tube, etc. Can be integrated, and a metal-coated wire can be manufactured by drawing until the composite material has a predetermined wire diameter. A softening treatment can be appropriately performed during the drawing process or before or after the drawing process.

  The Al alloy wire constituting the central strand 22 can be typically manufactured through steps of casting, rolling, wire drawing, and appropriate softening treatment (may be during wire drawing). If the softening treatment is performed to make it easy to stretch to some extent, it is easy to reduce disconnection during the wire drawing process in the process of forming the metal layer 24. As a basic method for producing an Al alloy wire, a known method for producing an Al alloy wire can be used.

  The conditions for the softening treatment applied to the Al alloy wire and the composite material are preferably adjusted in a range where the tensile strength of the finally obtained metal-coated wire satisfies both 130 MPa and 250 MPa and the elongation at break of 6% or more. As the softening treatment, either batch treatment or continuous treatment can be used. Examples of the batch processing conditions include a heating temperature of about 250 ° C. to 500 ° C. and a holding time of about 0.5 hours to 6 hours. When the atmosphere of the softening process is an atmosphere having a low oxygen content such as an air atmosphere or a non-oxidizing atmosphere, the oxidation of the Al alloy wire and the metal layer 24 can be reduced. Examples of the non-oxidizing atmosphere include a reduced pressure atmosphere, an inert gas atmosphere, a reducing gas atmosphere containing hydrogen, carbon dioxide gas, and the like and an inert gas.

[effect]
In the flat cable 1 according to the first embodiment, the conductor 20 of at least one insulated wire 2 among the plurality of insulated wires 2 is a metal-coated wire mainly composed of an Al alloy, so that the conductors of all the insulated wires are made of copper. It is lightweight compared to the case. And since the flat cable 1 of Embodiment 1 has a tensile strength of the metal-coated wire of 130 MPa or more and 250 MPa or less and an elongation at break of 6% or more, it has mechanical properties such as flexibility, strength, toughness, and impact resistance. Also excellent. This effect will be specifically described in test examples described later.

  Since the metal-coated wire is substantially composed of an Al alloy (center wire 22) and copper or a copper alloy (metal layer 24), the conductivity is high. Further, when the conductor 20 is exposed by removing the insulation coating 25 from the insulated wire 2 by attaching a terminal or the like, the outer peripheral surface of the metal layer 24 is exposed to the atmosphere, but the central strand 22 made of an Al alloy is exposed. The outer peripheral surface is substantially not exposed to the atmosphere. Therefore, when a terminal is attached to the conductor 20 at the end of the flat cable 1, a natural oxide film that can be formed on the Al alloy surface is not substantially interposed between the conductor 20 and the terminal. Therefore, the flat cable 1 can construct a connection structure with a low connection resistance between the conductor 20 and the terminal.

  The flat cable 1 according to the first embodiment can be used for indoor wiring, particularly low-voltage (typically 600 V or less) wiring laid in a building such as a house or apartment. When using the flat cable 1 for indoor wiring, since the flat cable 1 is lightweight, it can reduce the burden on the operator when laying.

[Test Example 1]
The mass and mechanical characteristics of a flat cable in which an Al alloy wire composed of an aluminum alloy is used as a central wire and a metal-coated wire having a copper metal layer on the outer periphery of the central wire is used as a conductor of an insulated wire were investigated. .

In this test, an Al alloy wire composed of an Al alloy containing the following additive elements and the balance being Al and inevitable impurities is used as a central strand. The unit of content of each element is mass%.
(1) 2.0% Fe
(2) 1.0% Fe, 0.2% Mg, 0.02% Ti, 0.004% B
(3) 1.0% Fe, 0.2% Mg, 0.04% Si, 0.03% Ti, 0.005% B
(4) 0.1% Fe, 0.05% Cu, 0.02% Ti, 0.004% B
(5) Fe 0.8%, Cu 0.02%
(6) 0.001% Fe, 0.02% Ti, 0.004% B

  An Al alloy melt having the above composition is prepared, and an Al alloy wire is produced through the steps of casting, rolling, wire drawing, and softening treatment as appropriate. The obtained Al alloy wire is inserted and arranged in a pipe material made of pure copper having a Cu content of 99.9% by mass or more to form a composite material, and this composite material is subjected to wire drawing. A softening treatment is appropriately performed to adjust the tensile strength and breaking elongation of the finally obtained metal-coated wire. Here, a metal-coated wire having a wire diameter (conductor diameter) of 2.0 mm or 2.6 mm, a metal layer area ratio of 15%, and a circular cross-sectional shape is produced. The area ratio of the metal layer is the ratio of the area of the metal layer to the entire cross-sectional area of the metal-coated wire having the above-mentioned wire diameter ([(cross-sectional area of the metal layer / cross-sectional area of the metal-coated wire)] × 100). It is preferable to adjust the thickness of the pipe material and the degree of wire drawing so that the area ratio of the metal layer is 15%.

  Table 1 shows the tensile strength (MPa), 0.2% yield strength (MPa), elongation at break (%), and electrical conductivity (% IACS) of the metal-coated wires. Tensile strength, 0.2% proof stress, and elongation at break were measured using a general-purpose tensile tester in accordance with JIS Z 2241 (metal material tensile test method, 1998). The conductivity was measured by the bridge method. Table 1 shows a sample having a wire diameter of 2.0 mm. When compared with the same composition, the sample with a wire diameter of 2.6 mm tends to have lower tensile strength and 0.2% proof stress than the wire diameter of 2.0 mm, and tends to have higher elongation at break. The rate is substantially the same.

  An insulation coating (here, polyvinyl chloride, thickness 0.8 mm) is formed on the outer periphery of the metal-coated wire to form an insulated wire, and a sheath portion (here, polyvinyl chloride) with two or three insulated wires arranged side by side , Thickness 1.5 mm). All the conductors of each insulated wire provided in the flat cable of each sample are metal-coated wires. Tables 2 to 5 show the mass of the flat cable of each sample (approximate mass (kg) per km). Tables 2 to 5 also show the mass of a flat cable having a copper conductor insulated wire as a comparative cable. Specifications such as the insulation coating and the sheath material and thickness of the comparison cable are the same as those of the flat cable of each sample provided with the above-described metal-coated wire.

(Flexibility)
About the flat cable and comparative cable of each sample, the following bending amount was measured and the flexibility was evaluated. The evaluation results are shown in Tables 2 to 5.
For the amount of bending, a test wire having a length of 200 mm is taken from each cable, one end of the test wire arranged horizontally is fixed, and a load is applied to the other end. Here, assuming that the worker bends the VVF for indoor wiring by hand, a load selected in the range of 5N to 10N is applied, and the other end of the test wire is bent downward. With the other end of the test wire bent by application of the predetermined load, the vertical distance L1 from the initial position at the other end of the test wire is measured downward. Thereafter, in the unloaded state, the downward vertical distance L2 from the initial position at the other end of the test wire is measured. When the test wire is bent downward by the application of the predetermined load (in this case, the vertical distance L1 is 100 mm or more), it is considered that the test wire has flexibility enough to be bent by an operator. . When the bent state after unloading is maintained to some extent (here, when the difference between the distance L1 in the load application state and the distance L2 after unloading is 80 mm or less), the degree to which the bent state can be maintained Is considered to have shape retention. Here, the case where the vertical distance L1 in the load application state is 100 mm or more is evaluated as A, and the case where it is less than 100 mm is evaluated as B. The case where the above-mentioned distance difference (L1-L2) is 80 mm or more is evaluated as a, and the case where it is less than 80 mm is evaluated as b.

(Difficult to disconnect)
About the flat cable of each sample, and the comparison cable, the following bending tests were done and the difficulty of disconnection was evaluated. Evaluation results (disconnection) are shown in Tables 2 to 5.
The bending test is performed according to JIS C 3005 (2014) 4.27.4 (a) “flat structure (code)”. The diameter of the cylinder along which the test piece is placed is 20 mm. The work of rotating about 180 ° alternately to the left and right is set as one time, and after 50 times of continuous rotating work at a speed of about 10 times per minute, the number of conductors and the like are visually checked. The number of conductor breaks when a bending test is performed for each sample by five is examined, and the number of conductor breaks is used as an evaluation parameter.

(Impact resistance)
The following tensile impact strength test was performed on the flat cable and the comparative cable of each sample to evaluate the impact resistance. The evaluation results (impact resistance) are shown in Tables 2 to 5.
A test wire having a length of 1000 mm is taken from each cable, and one end of the test wire is fixed. A weight of 3 kg is suspended from the tip (the other end) of the test wire, and the weight is lifted to the fixed end while a current of about 0.1 A is applied to the test wire, and then dropped. This operation is performed five times to check whether or not the current is interrupted during the five operations, and whether or not the current is interrupted is used as an evaluation parameter. If the current is not interrupted, it can be said that the impact resistance is excellent.

  As shown in Table 2 to Table 5, as a conductor of an insulated wire provided in a flat cable, when a metal-coated wire in which an outer periphery of a central element wire made of an Al alloy is covered with a copper metal layer is provided, It turns out that it is lightweight compared with the case where it provides. Here, it can be seen that the weight can be reduced by 25% or more, and further by about 30%. In addition, by satisfying the tensile strength of this metal-coated wire of 130 MPa or more and 250 MPa or less and the elongation at break of 6% or more, it has flexibility, strength, toughness, impact resistance, etc. comparable to copper conductors. It turns out that it is hard to break.

  From the above description, a conductor of an insulated wire is a metal-coated wire comprising a central element wire made of an Al alloy and a copper or copper alloy metal layer, the tensile strength and elongation satisfying a specific range. It has been shown that the flat cable provided for is lightweight and has excellent mechanical properties. Also. The Al alloy constituting the central strand is assumed to contain Fe in a specific range, or include Fe and the above-mentioned specific element in a specific range, and appropriately subjected to softening treatment, whereby the above-described tensile strength and It has been shown that a metal-coated wire having an elongation at break satisfying a specific range can be obtained.

The present invention is not limited to these exemplifications, but is defined by the scope of the claims, and is intended to include all modifications within the scope and meaning equivalent to the scope of the claims. For example, the following modifications can be made to the flat cable shown in the first embodiment and the first test example.
(1) Change the number of insulated wires provided in the flat cable, the conductor diameter, the thickness of the insulating coating, the thickness of the sheath, the constituent materials of the insulating coating and the sheath, and the like.
(2) As an insulated wire provided in a flat cable, an insulated wire having a different Al alloy constituting the central element wire of the conductor is provided.
(3) A ground wire is provided. In this case, the sheath part may be formed integrally with a holding part that holds the ground wire. A flat cable provided with a grounding wire can be used for electrical wiring such as an electric machine device requiring grounding, for example, an air conditioner, an electric water heater, and an IH cooking heater.

[Appendix]
As a flat cable that is lightweight and excellent in mechanical characteristics, the following configuration can be adopted.
[Appendix 1]
A plurality of insulated wires comprising a conductor and an insulating coating covering the conductor;
A sheath portion that integrally covers the plurality of insulated wires side by side,
Among the plurality of insulated wires, the conductor of at least one insulated wire is:
A metal-coated wire comprising a central strand composed of an aluminum alloy and a metal layer composed of copper or a copper alloy covering the central strand;
The aluminum alloy contains 0.005% by mass to 2.2% by mass of Fe, and the balance is Al and inevitable impurities.
[Appendix 2]
The aluminum alloy further includes one or more elements selected from Mg, Si, Cu, Zn, Ni, Mn, Ag, Cr, Zr, and Y in total of 0.005% by mass to 1.0% by mass. The flat cable according to Supplementary Note 1, which is contained below.
[Appendix 3]
The aluminum alloy further contains at least one of Ti of 0.01% by mass to 0.05% by mass and B of 0.001% by mass to 0.005% by mass of [Appendix 1] or [Appendix 2]. ] Flat cable described in the above.

DESCRIPTION OF SYMBOLS 1 Flat cable 2, 2A, 2B Insulated electric wire 20 Conductor 22 Center element wire 24 Metal layer 25 Insulation coating 3 Sheath part

Claims (4)

A plurality of insulated wires comprising a conductor and an insulating coating covering the conductor;
A sheath portion that integrally covers the plurality of insulated wires side by side,
Among the plurality of insulated wires, the conductor of at least one insulated wire is:
A metal-coated wire comprising a central strand composed of an aluminum alloy and a metal layer composed of copper or a copper alloy covering the central strand;
A flat cable in which the metal-coated wire has a tensile strength of 130 MPa or more and 250 MPa or less, and the metal-coated wire has a breaking elongation of 6% or more.   The flat cable according to claim 1, wherein the aluminum alloy contains 0.005 mass% or more and 2.2 mass% or less of Fe, with the balance being Al and inevitable impurities.   The aluminum alloy further includes one or more elements selected from Mg, Si, Cu, Zn, Ni, Mn, Ag, Cr, Zr, and Y in total of 0.005% by mass to 1.0% by mass. The flat cable according to claim 2, which is contained below.   The flat cable according to any one of claims 1 to 3, wherein an area ratio of the metal layer in a cross section of the metal-coated wire is 10% or more and 30% or less.

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