JP4103978B2

JP4103978B2 - Manufacturing method of hermetic wire

Info

Publication number: JP4103978B2
Application number: JP08449899A
Authority: JP
Inventors: 真洋中山
Original assignee: Kurabe Industrial Co Ltd
Current assignee: Kurabe Industrial Co Ltd
Priority date: 1999-02-19
Filing date: 1999-02-19
Publication date: 2008-06-18
Anticipated expiration: 2019-02-19
Also published as: JP2000243151A

Description

【０００１】
【発明の属する技術分野】
本発明は、油や水などが毛細管現象によって電線内部に浸入したり、電線端末部から漏出するのを確実に防止できるとともに、端末加工が容易で生産性にも優れた気密電線に関するものである。
【０００２】
【従来の技術】
各種機器のリード線として使用される電線においては、屈曲性を向上させる目的から複数本の導体素線を撚り合わせた撚線導体が導体として使用されている。通常、この種の電線は、端末部分の絶縁体を除去して撚線導体を露出させた後、各種の用途に応じて適宜に端末加工処理を施して実使用に供されるのであるが、その際、電線端末部付近に油や水などが存在していると、毛細管現象によってそれらが導体内部を伝わって電線の長手方向に浸入して種々の問題を引き起こしてしまう。このような現象は、例えば、自動車の自動変速機のオイルケース内に配置されて使用されるリード線のように、電線の両端末間に圧力差があるような環境下で使用された場合に特に顕著であった。
【０００３】
そこで従来では、電線内部への油や水の浸入、電線端末部からの油の漏出を防ぐための手段として、例えば、特公平１−５９４６７号公報に開示されているように、電線をオイルケースに固定するための電線保持ケースの内部に導体露出部を形成した電線を配置し、該電線の露出した導体素線間にエポキシ樹脂等の熱硬化性樹脂を充填する方法や、特許公報第２８２５１４３号公報に開示されているように、複数の端子を装着した基板の端子挿入孔と該端子との間をハンダ付けにより密封して形成した端子保持板を筒状のハウジングと一体に成形し、該筒状のハウジングの電線導入部に液体漏出防止用の封止体を装着してあるコネクタを使用する方法や、特開平１０−２６９８６１号公報に開示されているように、電線として撚線導体を構成する各導体素線の外周面及び隙間にポリエチレン系樹脂等の水密材を充填した構成のものを使用する方法、などが提案されている。
【０００４】
【発明が解決しようとする課題】
しかしながら、まず、特公平１−５９４６７号公報に開示されている方法の場合は、充填材として使用するエポキシ樹脂等の熱硬化性樹脂が熱膨張や熱収縮に対して追従性が無くクラックが入り易いため、場合によっては油漏れを起こしてしまうという恐れがあった。この問題に対しては、例えば、特許第２７６６５５８号公報が、追従性が良くクラックの入りにくい樹脂材を使用することのできる油漏防止用電線保持ケースを提案しているのであるが、このような電線保持ケースは、上述した特許公報第２８２５１４３号公報に開示されているようなコネクタと同様に、その形状が非常に複雑で特殊であることからコストが上昇してしまうという問題があった。
【０００５】
次に、特開平１０−２６９８６１号公報に開示されているような、導体素線の外周面及び隙間に水密材を充填した構成の電線を使用する方法の場合は、水密材が導体素線に付着した状態で硬化しているため、例えば、電線端末部に圧着端子を接続する場合など、導体素線に強固に付着した水密材を除去しなければならず、端末加工に長時間を要してしまうという問題があった。
【０００６】
本発明はこのような点に基づいてなされたもので、その目的とするところは、油や水などが毛細管現象によって電線内部に浸入したり、電線端末部から漏出するのを確実に防止できるとともに、端末加工が容易で生産性にも優れた気密電線を安価に提供することにある。
【０００７】
【課題を解決するための手段】
上記目的を達成するべく本発明による気密電線の製造方法は、複数本の導体素線と、熱可塑性樹脂からなる繊維束とを最外層には導体素線が配置されるように撚り合せて撚線導体を構成し、該撚線導体について、最外層に配置された各導体素線が相互に密着するように径方向に圧縮し、該導体素線の長さ方向の少なくとも一部を加熱することで繊維束を溶融して該繊維束を構成する熱可塑性樹脂を各導体素線間に充填し、上記導体素線の外周に絶縁体を被覆することを特徴とするものである。
【０００８】
【発明の実施の形態】
導体素線の構成材料は特に限定されず、従来公知の導体材料をいずれも使用することができる。
【０００９】
本発明で使用される熱可塑性樹脂からなる繊維束とは、熱可塑性樹脂繊維を束ねたものである。熱可塑性樹脂繊維としては、従来より様々な種類のものが公知であり、例えば、ポリエステル繊維、ポリフッ化ビニリデン繊維、ポリ塩化ビニリデン繊維、ポリプロピレン繊維、ポリエチレン繊維、ポリアミド繊維などが挙げられる。これらは、本発明によって得られる電線の使用条件（用途、要求機能等）や、後述する絶縁体の種類、気密部の形成方法（加熱方法等）などを考慮して適宜に選択すれば良い。
【００１０】
絶縁体は、従来公知の様々な絶縁被覆材料を公知の押出機を用いて撚線導体上に押出被覆することにより形成されるものであり、絶縁被覆材料の種類によっては適宜に架橋処理が施される。絶縁被覆材料の種類は、本発明によって得られる電線の使用条件（用途、要求機能等）を考慮して選択されるものであり特に限定されない。
【００１１】
本発明においては、上記した熱可塑性樹脂からなる繊維束と導体素線とを少なくとも最外層には導体素線が配置されるように撚り合わせて撚線導体を形成するのであるが、この際、最外層に配置された各導体素線が相互に密着するように径方向に圧縮しておくことが考えられる。こうしておけば、撚線導体に気密部を形成する際、繊維束を加熱することによって溶融した熱可塑性樹脂が導体素線の隙間から流出してしまうのを効果的に防止することができ、端子加工の際などに導体素線に付着した樹脂材をわざわざ除去する必要が無くなる。尚、導体素線への圧縮加工は、撚線導体の形成時に行わなくても、撚線導体を形成した後の気密部形成時に所定の圧力を加えながら行っても良い。
【００１２】
気密部は、油や水などが毛細管現象によって電線内部に浸入したり、電線内部に浸入した油や水が電線端末部から漏出するのを防止するためのものであり、上記の熱可塑性樹脂繊維束を加熱溶融させることによって、撚線導体の長さ方向の少なくとも一部（一部分、複数部分又は全部）に形成される。この気密部を撚線導体の一部分に形成するか、複数部分に形成するか、全部に形成するかは、本発明によって得られる電線の使用条件（用途、要求機能等）を考慮して選択されるものであり特に限定されない。又、その形成方法も特に限定されず様々な方法が考えられる。
【００１３】
例えば、絶縁体を被覆する前の撚線導体の長さ方向の少なくとも一部を各種の加熱装置で加熱して熱可塑性樹脂繊維束を溶融させる方法、絶縁体を押出被覆する際の熱で撚線導体を長さ方向に連続的に加熱して熱可塑性樹脂繊維束を溶融させる方法、絶縁体形成後の電線の長さ方向の少なくとも一部を加熱して熱可塑性樹脂繊維束を溶融させる方法、絶縁体に加熱架橋を施す場合には、その熱によって熱可塑性樹脂繊維束を溶融させる方法などが挙げられる。これらの方法は、電線製造時における形成方法の一例であるが、これらの方法以外にも、例えば、所定の長さに切断した電線に端末加工を施して組立品とする際に形成することも考えられる。
【００１４】
例えば、端末加工を施す際に、接続端子のインシュレーションバレル部分を各種の加熱装置で加熱して熱可塑性樹脂繊維束を溶融させる方法、電線組立品の長さ方向の少なくとも一部を、予め加熱しておいたカシメ金具でカシメることによって熱可塑性樹脂繊維束を溶融させる方法、電線組立品の長さ方向の所定位置にブッシングをモールド成形により形成し、その際の射出樹脂の熱と圧力によって熱可塑性樹脂繊維束を溶融させる方法など挙げられる。尚、これらの方法の中でも、電線組立品の少なくとも一部にカシメ部を形成する方法の場合には、予め撚線導体が圧縮されていなくても、カシメ時に加わる圧力によって各導体素線が径方向に圧縮されることになる。
【００１５】
【実施例】
以下に本発明の実施例を比較例と併せて説明する。尚、本実施例では、導体素線として錫メッキ軟銅線を使用した。又、熱可塑性樹脂繊維束としては、ポリエチレンテレフタレート繊維束を使用した。
【００１６】
本実施例
素線径０．１８ｍｍの錫メッキ軟銅線１６本と、融点２６０℃、太さ５００デニールのポリエチレンテレフタレート繊維束３束をピッチ７．０ｍｍで最外層には錫メッキ軟銅線が配置されるように撚り合わせた後、最外層に配置された錫メッキ軟銅線同士が相互に密着するように径方向に圧縮して外径０．８２５ｍｍの撚線導体を形成した。次に、この撚線導体上にフッ素ゴム混合物を０．４ｍｍの肉厚で押出被覆して絶縁体を形成し、公知の方法で架橋して仕上外径１．７ｍｍの電線を得た。そして最後に、電線表面の幅２０ｍｍの部分に３００℃の熱風を２０秒間当てることによりポリエチレンテレフタレート繊維束を加熱溶融させて気密部を形成した。本実施例では、この作業を電線の長さ方向に３００ｍｍの間隔をあけながら繰り返し、長さ方向に複数の気密部が形成された気密電線を製造した。図１は、このようにして得られた気密電線の気密部における断面図である。ここで、符号１が撚線導体、符号１ａが導体素線、符号１ｂが気密部、符号２が絶縁体である。
【００１７】
比較例
この例では、実施例で用いたポリエチレンテレフタレート繊維束を使用せずに、素線径０．１８ｍｍの錫メッキ軟銅線１９本を撚り合わせた後、径方向に圧縮して外径０．８２５ｍｍの撚線導体を形成した。次に、この撚線導体上にフッ素ゴム混合物を０．４ｍｍの肉厚で押出被覆して絶縁体を形成し、公知の方法で架橋して図２に示すような仕上外径１．７ｍｍの電線を得た。図２において、符号１１が撚線導体、符号１１ａが導体素線、符号１２が絶縁体である。
【００１８】
ここで、上記２種類の電線を試料として、気密性、漏油性及び端子加工性（端末加工性）についての評価を行った。評価方法は以下に示す通りである。評価結果は表１に示した。
【００１９】
気密性
長さ５００ｍｍに切断した試料の片端末に２．０ｋｇｆ／ｃｍ^２の空気圧をかけ、５分間で試料の他端末から漏出した空気の量を測定した。
漏油性
長さ５００ｍｍに切断した試料の片端末を油の中に浸漬し、油面に２．０ｋｇｆ／ｃｍ^２の圧力をかけ、２４時間で試料の他端末から漏出した油の量を測定した。試験油は、日産マチックフルードＤオイルを使用した。
端子加工性（端末加工性）
本実施例による試料については、気密部が形成された部分の絶縁体をストリップして撚線導体表面への熱可塑性樹脂の付着状態を目視にて確認した。又、比較例による試料については、長さ方向の任意の位置の絶縁体を幅２０ｍｍだけストリップして撚線導体表面への絶縁被覆材料の付着状態を目視にて確認した。
【００２０】
【表１】

【００２１】
その結果、比較例の電線では空気漏れと油漏れが確認されたのに対して、本実施例による電線では空気漏れも油漏れも全く確認されなかった。つまり、本実施例による電線は、油や水などが毛細管現象によって電線内部へ浸入したり、電線端末部から漏出したりすることを確実に防止できる電線であることがわかった。又、本実施例による電線は、端子加工性（端末加工性）についても、撚線導体の表面に樹脂が全く付着しておらず、比較例の電線と同等の加工性を有していた。
【００２２】
【発明の効果】
以上詳述したように本発明の気密電線は、撚線導体の長さ方向の少なくとも一部に、熱可塑性樹脂繊維束を加熱溶融させることによって形成された気密部が設けられているので、油や水などが毛細管現象によって電線内部に浸入したり、電線端末部から漏出するのを確実に防止できる。又、端末加工が容易であるとともに、通常の電線を製造する場合と同様の方法で簡単に製造することができるため、低コストで提供することができる。従って、例えば、自動車の自動変速機のオイルケース内に配置されるリード線など、幅広い用途で好適に使用することが可能である。
【図面の簡単な説明】
【図１】本発明の一実施例を示す図で、気密電線の断面図である。
【図２】比較例を示す図で、気密部を形成していない電線の断面図である。
【符号の説明】
１…撚線導体
１ａ…導体素線
１ｂ…気密部
２…絶縁体[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an airtight electric wire that can reliably prevent oil or water from entering the inside of a wire by a capillary phenomenon or leaking from the end portion of the wire, and is easy to process the end and excellent in productivity. .
[0002]
[Prior art]
In electric wires used as lead wires for various devices, a stranded wire conductor obtained by twisting a plurality of conductor strands is used as a conductor for the purpose of improving flexibility. Usually, this type of electric wire is used for actual use after removing the insulator of the terminal part and exposing the stranded conductor, and then appropriately processing the terminal according to various applications. At that time, if oil, water, or the like is present near the end portion of the electric wire, they are transmitted through the inside of the conductor due to a capillary phenomenon, and enter the longitudinal direction of the electric wire, thereby causing various problems. Such a phenomenon occurs when used in an environment where there is a pressure difference between both ends of the wire, such as a lead wire that is used in an oil case of an automatic transmission of an automobile. It was particularly remarkable.
[0003]
Therefore, conventionally, as a means for preventing the intrusion of oil and water into the electric wire and the leakage of the oil from the end portion of the electric wire, for example, as disclosed in Japanese Patent Publication No. 1-59467 , the electric wire is connected to the oil case. An electric wire in which a conductor exposed portion is formed inside an electric wire holding case for fixing to an electric wire, and a method in which a thermosetting resin such as epoxy resin is filled between exposed conductor wires of the electric wire, or Japanese Patent Publication No. 2825143. As disclosed in the publication, a terminal holding plate formed by sealing between a terminal insertion hole of a substrate on which a plurality of terminals are mounted and the terminal is formed integrally with a cylindrical housing, A method of using a connector in which a sealing body for preventing liquid leakage is attached to an electric wire introduction portion of the cylindrical housing, or a twisted conductor as an electric wire as disclosed in JP-A-10-269861 Configure How to use a structure filled with watertight material such as polyethylene resin, and the like have been proposed to the outer peripheral surface and gaps between the conductor wires that.
[0004]
[Problems to be solved by the invention]
However, first, in the case of the method disclosed in Japanese Patent Publication No. 1-59467, a thermosetting resin such as an epoxy resin used as a filler has no followability with respect to thermal expansion and contraction and cracks occur. Since it was easy, there was a risk of causing oil leakage in some cases. For this problem, for example, Japanese Patent No. 2766558 proposes an oil leakage prevention electric wire holding case that can use a resin material that has good followability and is difficult to crack. As in the case of the connector disclosed in the above-mentioned Japanese Patent Publication No. 2825143, the simple electric wire holding case has a problem that its shape is very complicated and special, which increases the cost.
[0005]
Next, in the case of a method of using an electric wire having a structure in which a watertight material is filled in the outer peripheral surface and gaps of a conductor wire as disclosed in JP-A-10-269861, the watertight material is used as the conductor wire. Because it is hardened in the attached state, for example, when connecting a crimp terminal to the end of the wire, the watertight material that adheres firmly to the conductor wire must be removed, which requires a long time for terminal processing. There was a problem that.
[0006]
The present invention has been made based on such points, and the object of the present invention is to reliably prevent oil or water from entering the inside of the electric wire or leaking out from the electric wire end portion by capillary action. It is to provide an airtight electric wire which is easy to process a terminal and excellent in productivity at low cost.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the method of manufacturing an airtight electric wire according to the present invention twists a plurality of conductor strands and a fiber bundle made of thermoplastic resin by twisting them so that the conductor strands are arranged in the outermost layer. A wire conductor is formed, and the stranded wire conductor is compressed in the radial direction so that the conductor wires arranged in the outermost layer are in close contact with each other, and at least a part of the length of the conductor wire is heated. Thus, the fiber bundle is melted and the thermoplastic resin constituting the fiber bundle is filled between the conductor strands, and the outer periphery of the conductor strand is covered with an insulator .
[0008]
DETAILED DESCRIPTION OF THE INVENTION
The constituent material of the conductor strand is not particularly limited, and any conventionally known conductor material can be used.
[0009]
The fiber bundle made of a thermoplastic resin used in the present invention is a bundle of thermoplastic resin fibers. Various types of thermoplastic resin fibers are conventionally known, and examples thereof include polyester fibers, polyvinylidene fluoride fibers, polyvinylidene chloride fibers, polypropylene fibers, polyethylene fibers, and polyamide fibers. These may be appropriately selected in consideration of the use conditions (uses, required functions, etc.) of the electric wire obtained by the present invention, the type of insulator described later, the formation method of the airtight part (heating method, etc.), and the like.
[0010]
The insulator is formed by extruding and coating various conventionally known insulating coating materials on a stranded conductor using a known extruder. Depending on the type of the insulating coating material, an appropriate crosslinking treatment is performed. Is done. The type of the insulation coating material is not particularly limited, and is selected in consideration of the use conditions (application, required function, etc.) of the electric wire obtained by the present invention.
[0011]
In the present invention, the fiber bundle made of the thermoplastic resin and the conductor strand are twisted so that the conductor strand is disposed at least on the outermost layer to form a stranded conductor. It is conceivable that the conductor wires arranged on the outermost layer are compressed in the radial direction so that they are in close contact with each other. If it does in this way, when forming an airtight part in a strand wire conductor, it can prevent effectively that the thermoplastic resin which melted by heating a fiber bundle flows out from the crevice between conductor wires, and a terminal. There is no need to remove the resin material adhering to the conductor wire during processing. In addition, you may perform the compression process to a conductor strand, applying a predetermined pressure at the time of formation of the airtight part after forming a stranded wire conductor, without performing it at the time of formation of a stranded wire conductor.
[0012]
The airtight part is intended to prevent oil or water from entering the inside of the electric wire due to capillary action, or to prevent oil or water that has entered the inside of the electric wire from leaking out from the end of the electric wire. By heating and melting the bundle, it is formed in at least a part (a part, a plurality of parts, or the whole) of the stranded wire conductor in the length direction. Whether the airtight part is formed in a part of the stranded wire conductor, a plurality of parts, or the whole is selected in consideration of the use conditions (application, required function, etc.) of the electric wire obtained by the present invention. There is no particular limitation. Also, the formation method is not particularly limited, and various methods are conceivable.
[0013]
For example, a method of melting a thermoplastic resin fiber bundle by heating at least a part of the length direction of a stranded wire conductor before coating the insulator with various heating devices, and twisting with heat at the time of extrusion coating of the insulator A method of melting a thermoplastic resin fiber bundle by heating the wire conductor continuously in the length direction, and a method of melting at least a part of the length direction of the electric wire after forming the insulator to melt the thermoplastic resin fiber bundle In the case where the insulator is subjected to heat crosslinking, a method of melting the thermoplastic resin fiber bundle by the heat, and the like can be mentioned. These methods are examples of the forming method at the time of manufacturing the electric wire, but other than these methods, for example, it is also possible to form the wire by cutting the electric wire into a predetermined length to make an assembly. Conceivable.
[0014]
For example, when terminal processing is performed, the insulation barrel portion of the connection terminal is heated with various heating devices to melt the thermoplastic resin fiber bundle, and at least a part of the length direction of the wire assembly is preheated. A method of melting a thermoplastic resin fiber bundle by caulking with a caulking metal fitting, a bushing is formed at a predetermined position in the length direction of the electric wire assembly by molding, and the heat and pressure of the injection resin at that time Examples include a method of melting a thermoplastic resin fiber bundle. Of these methods, in the case of a method of forming a crimped portion in at least a part of an electric wire assembly, each conductor wire is diametrically affected by pressure applied during crimping even if the twisted conductor is not compressed in advance. Will be compressed in the direction.
[0015]
【Example】
Examples of the present invention will be described below together with comparative examples. In this example, tin-plated annealed copper wire was used as the conductor wire. A polyethylene terephthalate fiber bundle was used as the thermoplastic resin fiber bundle.
[0016]
Example: Sixteen tin-plated annealed copper wires having a wire diameter of 0.18 mm and three bundles of polyethylene terephthalate fiber bundles having a melting point of 260 ° C and a thickness of 500 denier and a pitch of 7.0 mm and tin-plated annealed copper as the outermost layer After twisting the wires so that the wires were arranged, they were compressed in the radial direction so that the tin-plated annealed copper wires arranged in the outermost layer were in close contact with each other to form a twisted wire conductor having an outer diameter of 0.825 mm. Next, the fluororubber mixture was extruded and coated with a thickness of 0.4 mm on the stranded conductor to form an insulator, which was then crosslinked by a known method to obtain an electric wire having a finished outer diameter of 1.7 mm. And finally, the polyethylene terephthalate fiber bundle was heated and melted by applying hot air at 300 ° C. for 20 seconds to a 20 mm wide part on the surface of the electric wire to form an airtight part. In this example, this operation was repeated with an interval of 300 mm in the length direction of the electric wire, and an airtight electric wire in which a plurality of airtight portions were formed in the length direction was manufactured. FIG. 1 is a cross-sectional view of the hermetic portion of the hermetic wire thus obtained. Here, reference numeral 1 denotes a stranded conductor, reference numeral 1a denotes a conductor wire, reference numeral 1b denotes an airtight portion, and reference numeral 2 denotes an insulator.
[0017]
Comparative example In this example, without using the polyethylene terephthalate fiber bundle used in the examples, 19 tin-plated annealed copper wires having a strand diameter of 0.18 mm were twisted and then compressed in the radial direction. A stranded conductor having an outer diameter of 0.825 mm was formed. Next, an insulator is formed by extrusion coating the fluororubber mixture with a thickness of 0.4 mm on the stranded wire conductor, and is crosslinked by a known method to have a finished outer diameter of 1.7 mm as shown in FIG. I got an electric wire. In FIG. 2, the code | symbol 11 is a stranded wire conductor, the code | symbol 11a is a conductor strand, and the code | symbol 12 is an insulator.
[0018]
Here, airtightness, oil leakage, and terminal processability (terminal processability) were evaluated using the two types of electric wires as samples. The evaluation method is as follows. The evaluation results are shown in Table 1.
[0019]
Air tightness An air pressure of 2.0 kgf / cm ² was applied to one end of the sample cut to a length of 500 mm, and the amount of air leaked from the other end of the sample in 5 minutes was measured.
Oil leakage property One end of a sample cut to a length of 500 mm is immersed in oil, pressure of 2.0 kgf / cm ² is applied to the oil surface, and oil leaks from the other end of the sample in 24 hours. The amount of was measured. The test oil used was Nissan Matic Fluid D oil.
Terminal processability (terminal processability)
About the sample by a present Example, the insulator of the part in which the airtight part was formed was stripped, and the adhesion state of the thermoplastic resin to the strand wire conductor surface was confirmed visually. Moreover, about the sample by a comparative example, the insulator of the arbitrary positions of a length direction was stripped only 20 mm in width, and the adhesion state of the insulation coating material to the strand wire conductor surface was confirmed visually.
[0020]
[Table 1]

[0021]
As a result, air leakage and oil leakage were confirmed in the electric wire of the comparative example, whereas neither air leakage nor oil leakage was confirmed in the electric wire according to this example. That is, it has been found that the electric wire according to the present example is an electric wire that can reliably prevent oil, water, and the like from entering the inside of the electric wire and leaking from the end portion of the electric wire due to a capillary phenomenon. Moreover, the electric wire according to this example also had terminal machinability (terminal machinability), and no resin adhered to the surface of the stranded conductor, and had the same machinability as the electric wire of the comparative example.
[0022]
【The invention's effect】
As described above in detail, the hermetic wire of the present invention is provided with an airtight part formed by heating and melting a thermoplastic resin fiber bundle at least in a part of the length direction of the stranded conductor. It is possible to reliably prevent water and water from entering the inside of the electric wire and leaking from the end portion of the electric wire due to a capillary phenomenon. Moreover, since it is easy to process the terminal, it can be easily manufactured by the same method as that for manufacturing an ordinary electric wire, so that it can be provided at low cost. Therefore, for example, it can be suitably used in a wide range of applications such as a lead wire disposed in an oil case of an automatic transmission of an automobile.
[Brief description of the drawings]
FIG. 1 is a diagram showing an embodiment of the present invention and a cross-sectional view of an airtight electric wire.
FIG. 2 is a cross-sectional view of an electric wire in which an airtight portion is not formed, showing a comparative example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Twisted wire conductor 1a ... Conductor strand 1b ... Airtight part 2 ... Insulator

Claims

A plurality of conductor strands and a fiber bundle made of thermoplastic resin are twisted so that the conductor strands are arranged in the outermost layer to form a stranded conductor, and the stranded conductor is arranged in the outermost layer. Thermoplastic that forms the fiber bundle by compressing in the radial direction so that the respective conductor wires are in close contact with each other and heating at least part of the length of the conductor strand to melt the fiber bundle A method for producing an airtight electric wire in which a resin is filled between conductor wires and an outer periphery of the conductor wire is covered with an insulator.

A plurality of conductor strands and a fiber bundle made of thermoplastic resin are twisted so that the conductor strands are arranged in the outermost layer to form a stranded conductor, and the stranded conductor is arranged in the outermost layer. The conductor strands are compressed in a radial direction so that they are in close contact with each other, and an insulator is extruded and coated on the outer periphery of the conductor strands, and at the same time, the fiber bundle is melted by heat during the extrusion coating. A method for manufacturing an airtight electric wire, in which a thermoplastic resin constituting a fiber bundle is filled between conductor wires.

A plurality of conductor strands and a fiber bundle made of thermoplastic resin are twisted so that the conductor strands are arranged in the outermost layer to form a stranded conductor, and the stranded conductor is arranged in the outermost layer. By compressing in a radial direction so that the conductor wires are in close contact with each other, covering the outer periphery of the conductor wires with an insulator to form an electric wire, and heating at least a part of the length of the electric wire by heating A method for producing an airtight electric wire, in which a fiber bundle is melted and a thermoplastic resin constituting the fiber bundle is filled between conductor wires.

A plurality of conductor strands and a fiber bundle made of thermoplastic resin are twisted so that the conductor strands are arranged in the outermost layer to form a stranded conductor, and the stranded conductor is arranged in the outermost layer. The conductor wires are compressed in the radial direction so that they are in close contact with each other, and the insulator is coated on the outer periphery of the conductor wires, and the insulator is heated and crosslinked at the same time as the heat during the heating and crosslinking. A method for producing an airtight electric wire, in which a fiber bundle is melted and a thermoplastic resin constituting the fiber bundle is filled between conductor wires.