JP5501258B2 - Superconducting wire connection structure and manufacturing method thereof - Google Patents

Superconducting wire connection structure and manufacturing method thereof Download PDF

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JP5501258B2
JP5501258B2 JP2011008579A JP2011008579A JP5501258B2 JP 5501258 B2 JP5501258 B2 JP 5501258B2 JP 2011008579 A JP2011008579 A JP 2011008579A JP 2011008579 A JP2011008579 A JP 2011008579A JP 5501258 B2 JP5501258 B2 JP 5501258B2
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JP2012150978A (en
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一宗 児玉
毅 和久田
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Hitachi Healthcare Manufacturing Ltd
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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C9/00—Alloys based on copper
    • C22C9/06—Alloys based on copper with nickel or cobalt as the next major constituent
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
    • H01R4/00—Electrically-conductive connections between two or more conductive members in direct contact, i.e. touching one another; Means for effecting or maintaining such contact; Electrically-conductive connections having two or more spaced connecting locations for conductors and using contact members penetrating insulation
    • H01R4/58—Electrically-conductive connections between two or more conductive members in direct contact, i.e. touching one another; Means for effecting or maintaining such contact; Electrically-conductive connections having two or more spaced connecting locations for conductors and using contact members penetrating insulation characterised by the form or material of the contacting members
    • H01R4/68—Connections to or between superconductive connectors
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N60/00—Superconducting devices
    • H10N60/20—Permanent superconducting devices
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N60/00—Superconducting devices
    • H10N60/80—Constructional details

Description

本発明は、超電導線材同士の電気的な接続に関し、特に交流通電の超電導機器や永久電流スイッチに用いられ高いクエンチ耐性を有する接続構造体およびその製造方法に関するものである。   The present invention relates to electrical connection between superconducting wires, and particularly relates to a connection structure having high quench resistance and used for a superconducting device and a permanent current switch that are energized with alternating current, and a method for manufacturing the same.

超電導線材同士を電気的に接続する技術は、超電導線材を応用するにあたっての重要な技術のうちの１つである。最も簡便に接続する方法は、超電導線材同士を十分な長さでオーバーラップさせてはんだ付けする方法である（はんだ接続法と称する）。ここで、超電導線材は、一般に、超電導体からなる多数の超電導フィラメントが母材（例えば、銅やアルミニウムなど）に覆われた構造をしているため、はんだ接続法による接続では、一方の超電導フィラメントから流れてきた電流が、母材、はんだ、母材を経由して他方の超電導フィラメントへと流れ込むことになる。すなわち、はんだ接続法における接続抵抗は母材とはんだとの電気抵抗を含み、その結果、数メートル長さで超電導線材同士をオーバーラップさせた場合でも10-9Ω程度の接続抵抗となる。 The technology for electrically connecting superconducting wires is one of important technologies for applying superconducting wires. The simplest connection method is a method in which superconducting wires are overlapped with a sufficient length and soldered (referred to as a solder connection method). Here, since a superconducting wire generally has a structure in which a number of superconducting filaments made of a superconductor are covered with a base material (for example, copper, aluminum, etc.), one of the superconducting filaments is connected by a solder connection method. The current that has flowed from the current flows into the other superconducting filament via the base material, solder, and base material. That is, the connection resistance in the solder connection method includes the electrical resistance between the base material and the solder. As a result, even when the superconducting wires are overlapped with each other by several meters, the connection resistance is about 10 −9 Ω.

超電導線材およびそれによる超電導磁石を利用した代表的な製品として核磁気共鳴分析装置（NMR）や核磁気共鳴画像装置（MRI）があり、バイオテクノロジー分野や医療分野で広く利用されている。これらの装置は、通常、永久電流モードで運転され、磁場精度において0.1 ppm/h以下という極めて小さな磁場減衰率が要求されている。そして、永久電流モードや該磁場減衰率を達成するためには、少なくとも10-12Ω以下の低い接続抵抗での接続（いわゆる超電導接続）が必須の技術となる。 Typical products using superconducting wires and superconducting magnets there are a nuclear magnetic resonance analyzer (NMR) and a nuclear magnetic resonance imaging device (MRI), which are widely used in the biotechnology field and the medical field. These devices are normally operated in a permanent current mode, and require extremely small magnetic field attenuation rates of 0.1 ppm / h or less in magnetic field accuracy. In order to achieve the permanent current mode and the magnetic field attenuation factor, connection with a low connection resistance of at least 10 −12 Ω (so-called superconducting connection) is an essential technique.

そのような低い接続抵抗を達成する方法として、接続する超電導線材同士の接続予定部で母材を除去して超電導フィラメントを露出させ、その後、露出させた超電導フィラメント同士を重ね合わせて金属パイプに挿入し該金属パイプを加圧して潰すことで相互の超電導線フィラメントを圧着接続する方法（かしめ接続法と称する）が報告されている（例えば、特許文献１や非特許文献１参照）。かしめ接続法では、接続する相互の超電導線フィラメントが母材やはんだ等の常電導体を介さずに直接接触しているため、10-13Ω以下の接続抵抗を実現できる。このため、かしめ接続法は、接続抵抗に厳しい要求のあるNMRやMRIの超電導磁石における超電導接続部にもしばしば適用されている。 As a method to achieve such a low connection resistance, the superconducting filament is exposed by removing the base material at the connection portion between the superconducting wires to be connected, and then the exposed superconducting filaments are overlapped and inserted into a metal pipe. A method of crimping and connecting the superconducting wire filaments by pressurizing and crushing the metal pipe (referred to as a caulking connection method) has been reported (for example, see Patent Document 1 and Non-Patent Document 1). In the caulking connection method, since the superconducting wire filaments to be connected are in direct contact without passing through a normal conductor such as a base material or solder, a connection resistance of 10 −13 Ω or less can be realized. For this reason, the caulking connection method is often applied to superconducting connections in NMR and MRI superconducting magnets, which have strict requirements on connection resistance.

また、特許文献２には、かしめ接続法の一種であり、接続する相互の超電導線フィラメント間に二硼化マグネシウムを含む超電導粉末を接触介在させる超電導接続構造が開示されている。特許文献２によると、超電導線接続部が高磁場中に配置されていても低い電気抵抗での接続が可能であるとされている。   Patent Document 2 discloses a superconducting connection structure, which is a kind of caulking connection method, in which a superconducting powder containing magnesium diboride is interposed between the superconducting wire filaments to be connected. According to Patent Document 2, it is said that connection with a low electric resistance is possible even if the superconducting wire connection portion is arranged in a high magnetic field.

特開平４−３１９２８０号公報JP-A-4-319280 特開２００３−０２２７１９号公報JP 2003-022719 A

下畑賢司，山本俊二，中村史朗，川口武男：「NbTi超電導線の超電導接続」，低温工学 Vol. 30 pp. 70-75。Kenji Shimohata, Shunji Yamamoto, Shiro Nakamura, Takeo Kawaguchi: “Superconducting connection of NbTi superconducting wires”, Cryogenic Engineering Vol. 30 pp. 70-75.

超電導線材や超電導磁石に通電したとき、定格電流よりも低い電流値で超電導性が突然消失するクエンチと呼ばれる現象が発生することがある。クエンチの発生は、超電導線材を用いた製品の運転安定性・信頼性に係わる問題であり、クエンチの防止は、超電導製品における最重要課題のうちの１つである。   When a superconducting wire or a superconducting magnet is energized, a phenomenon called quenching may occur in which superconductivity suddenly disappears at a current value lower than the rated current. Generation | occurrence | production of a quench is a problem regarding the operation stability and reliability of the product using a superconducting wire, and prevention of quench is one of the most important subjects in a superconducting product.

かしめ接続法を適用した超電導接続部（例えば、特許文献１や非特許文献１参照）は、それ以外の部分と比較してクエンチが特に発生しやすい箇所である。その原因の１つは、接続のために母材を除去したためと考えられる。母材は、超電導線材の熱容量を大きくして擾乱による温度上昇を抑制するとともに、発生した熱の拡散を促す役割がある。しかしながら、かしめ接続法は接続のためにこれを除去することから、クエンチ耐性を低下させることつながったと考えられる。また、特許文献２に記載の超電導接続構造においても、クエンチ耐性が必ずしも十分とは言えなかった。   A superconducting connection portion to which the caulking connection method is applied (see, for example, Patent Document 1 and Non-Patent Document 1) is a portion where quenching is particularly likely to occur compared to other portions. One of the causes is considered that the base material is removed for connection. The base material has a role of enlarging the heat capacity of the superconducting wire to suppress the temperature rise due to disturbance and promoting the diffusion of the generated heat. However, since the caulking connection method removes this for connection, it is considered that the quench resistance is reduced. Moreover, even in the superconducting connection structure described in Patent Document 2, the quench resistance is not always sufficient.

一方、交流通電する超電導機器に用いられる超電導線材や、永久電流モードで運転する超電導機器に必須な永久電流スイッチに用いられる超電導線材などにおいては、通常の超電導線材の母材（例えば無酸素銅）よりも電気抵抗率が高い母材（例えば銅ニッケル合金）を用いた超電導線材が通常使用されるため、はんだ接続法の適用は不適当と考えられる。さらに、電気抵抗率が高い金属は熱伝導率が低いことから、これらの超電導線材では、母材が付いている状態であっても通常の超電導線材よりもクエンチ耐性が低下する傾向があり、クエンチ耐性の高い接続方法および接続構造体が強く望まれていた。   On the other hand, in a superconducting wire used for a superconducting device that is energized with alternating current or a superconducting wire used in a permanent current switch that is essential for a superconducting device that operates in a permanent current mode, a base material of an ordinary superconducting wire (for example, oxygen-free copper) Since a superconducting wire using a base material (for example, a copper-nickel alloy) having a higher electrical resistivity than that of the solder is generally used, it is considered that the solder connection method is inappropriate. Furthermore, since metals with high electrical resistivity have low thermal conductivity, these superconducting wires tend to be less resistant to quenching than ordinary superconducting wires, even when the base material is attached. A highly durable connection method and connection structure have been highly desired.

従って、本発明の目的は、交流通電の超電導機器や永久電流スイッチに用いられる超電導線材同士の電気的接続において、低い接続抵抗と高いクエンチ耐性とを兼ね備えた接続構造体およびその製造方法を提供することにある。   Accordingly, an object of the present invention is to provide a connection structure having both a low connection resistance and a high quench resistance in an electrical connection between superconducting wires used for an alternating current superconducting device and a permanent current switch, and a method for manufacturing the same. There is.

本発明は上記目的を達成するため、複数の超電導フィラメントが母材に覆われた構造を有する第１の超電導多芯線材と第２の超電導多芯線材とを電気的に接続する接続構造体であって、
前記第１および第２の超電導多芯線材のうちの少なくとも一方は、交流通電用または永久電流スイッチ用の超電導線材であり、
前記第１の超電導多芯線材の母材が除去されて露出した第１の超電導フィラメントの先端領域と、前記第２の超電導多芯線材の母材が除去されて露出した第２の超電導フィラメントの先端領域とは、かしめ接続されたジョイント部を構成し、
前記露出した第１の超電導フィラメントの残りの領域と、前記露出した第２の超電導フィラメントの残りの領域とは、被覆部材を介して接続されたバイパス部を構成し、
前記被覆部材は、前記接続構造体の運転環境下において、前記交流通電用または永久電流スイッチ用の超電導線材の母材よりも電気抵抗率が低い金属材料からなることを特徴とする超電導線材の接続構造体を提供する。 In order to achieve the above object, the present invention provides a connection structure for electrically connecting a first superconducting multicore wire and a second superconducting multicore wire having a structure in which a plurality of superconducting filaments are covered with a base material. There,
At least one of the first and second superconducting multicore wires is a superconducting wire for alternating current conduction or a permanent current switch,
A tip region of the first superconducting filament exposed by removing the base material of the first superconducting multicore wire, and a second superconducting filament exposed by removing the base material of the second superconducting multicore wire. The tip region constitutes a joint part that is caulked and connected,
The remaining area of the exposed first superconducting filament and the remaining area of the exposed second superconducting filament constitute a bypass portion connected via a covering member;
The covering member is made of a metal material having an electric resistivity lower than that of the base material of the superconducting wire for the alternating current conduction or the permanent current switch under the operating environment of the connection structure. Provide a structure.

また、本発明は上記目的を達成するため、複数のニオブチタン合金フィラメントが母材に覆われた構造を有する第１の超電導多芯線材と第２の超電導多芯線材とを電気的に接続する接続構造体の製造方法であって、
前記第１および第２の超電導多芯線材のうちの少なくとも一方は、交流通電用または永久電流スイッチ用の超電導線材であり、
前記第１および第２の超電導多芯線材における接続予定領域の前記母材を除去して第１および第２のニオブチタン合金フィラメントを露出させるフィラメント露出工程と、
前記露出した第１および第２のニオブチタン合金フィラメントの先端領域を金属パイプ内に挿入し、前記金属パイプを押圧変形することによって前記第１および第２のニオブチタン合金フィラメント同士を圧着してジョイント部を形成するジョイント部形成工程と、
前記接続構造体の運転環境下において、前記交流通電用または永久電流スイッチ用の超電導線材の母材よりも電気抵抗率が低い金属材料である被覆部材を、前記露出した第１の超電導フィラメントの残りの領域と、前記露出した第２の超電導フィラメントの残りの領域とに被覆・一体化してバイパス部を形成するバイパス部形成工程とを有することを特徴とする超電導線材の接続構造体の製造方法を提供する。 In order to achieve the above object, the present invention electrically connects a first superconducting multicore wire having a structure in which a plurality of niobium titanium alloy filaments are covered with a base material and a second superconducting multicore wire. A structure manufacturing method comprising:
At least one of the first and second superconducting multicore wires is a superconducting wire for alternating current conduction or a permanent current switch,
A filament exposing step of removing the base material in the connection planned region in the first and second superconducting multicore wires to expose the first and second niobium titanium alloy filaments;
Inserting the exposed tip regions of the first and second niobium titanium alloy filaments into a metal pipe and pressing and deforming the metal pipe, the first and second niobium titanium alloy filaments are crimped together to form a joint portion. A joint part forming step to be formed;
Under the operating environment of the connection structure, a covering member made of a metal material having a lower electrical resistivity than the base material of the superconducting wire for the alternating current conduction or the permanent current switch is left behind the exposed first superconducting filament. And a bypass portion forming step of forming a bypass portion by covering and integrating the remaining region of the exposed second superconducting filament with the remaining region of the exposed second superconducting filament. provide.

本発明によれば、交流通電の超電導機器や永久電流スイッチに用いられる超電導線材同士の電気的接続において、低い接続抵抗と高いクエンチ耐性とを兼ね備えた接続構造体およびその製造方法を提供することができる。   ADVANTAGE OF THE INVENTION According to this invention, in the electrical connection of the superconducting wire used for the superconducting apparatus and permanent current switch of alternating current conduction, the connection structure which has low connection resistance and high quench tolerance, and its manufacturing method are provided. it can.

かしめ接続による超電導線材同士の従来の接続構造体の１例を示す斜視模式図である。It is a perspective schematic diagram which shows an example of the conventional connection structure of the superconducting wire material by caulking connection. 本発明に係る超電導線材の接続構造体の１例を示す斜視模式図とバイパス部の断面模式図である。1 is a schematic perspective view showing an example of a superconducting wire connecting structure according to the present invention and a schematic cross-sectional view of a bypass portion. 本発明に係る超電導線材の接続構造体を示す等価回路である。It is an equivalent circuit which shows the connection structure of the superconducting wire which concerns on this invention. 本発明に係る超電導線材の接続構造体の他の１例を示す斜視模式図とバイパス部の断面模式図である。It is the perspective schematic diagram which shows another example of the connection structure of the superconducting wire which concerns on this invention, and the cross-sectional schematic diagram of a bypass part. 本発明に係る超電導線材の接続構造体の他の１例を示す斜視模式図とバイパス部の断面模式図である。It is the perspective schematic diagram which shows another example of the connection structure of the superconducting wire which concerns on this invention, and the cross-sectional schematic diagram of a bypass part. 本発明に係る超電導線材の接続構造体のジョイント部の変形例を示す断面模式図である。It is a cross-sectional schematic diagram which shows the modification of the joint part of the connection structure of the superconducting wire which concerns on this invention. 超電導線材の接続構造体の通電特性を測定するためのサンプル形状を示す模式図である。It is a schematic diagram which shows the sample shape for measuring the electricity supply characteristic of the connection structure of a superconducting wire. 本発明に係る実施例１を示す斜視模式図とバイパス部の断面模式図である。It is the perspective schematic diagram which shows Example 1 which concerns on this invention, and the cross-sectional schematic diagram of a bypass part. 超電導線材の接続構造体の通電特性を測定するための試験系を示す模式図である。It is a schematic diagram which shows the test system for measuring the electricity supply characteristic of the connection structure of a superconducting wire. 比較例１の通電特性の結果（捕捉した磁束の時間変化）の１例を示すチャートである。It is a chart which shows one example of the result of energization characteristics of comparative example 1 (time change of the captured magnetic flux). 実施例１の通電特性の結果（捕捉した磁束の時間変化）の１例を示すチャートである。It is a chart which shows one example of the result of energization characteristics of Example 1 (time change of the captured magnetic flux).

以下、本発明に係る実施形態について、図面を参照しながら説明する。ただし、本発明はここで取り上げた実施形態に限定されることはなく、要旨を変更しない範囲で適宜組み合わせや改良が可能である。   Hereinafter, embodiments according to the present invention will be described with reference to the drawings. However, the present invention is not limited to the embodiments taken up here, and can be appropriately combined and improved without departing from the scope of the invention.

前述したように、本発明に係る超電導線材の接続構造体は、複数の超電導フィラメントが母材に覆われた構造を有する第１の超電導多芯線材と第２の超電導多芯線材とを電気的に接続する接続構造体であって、
前記第１および第２の超電導多芯線材のうちの少なくとも一方は、交流通電用または永久電流スイッチ用の超電導線材であり、
前記第１の超電導多芯線材の母材が除去されて露出した第１の超電導フィラメントの先端領域と、前記第２の超電導多芯線材の母材が除去されて露出した第２の超電導フィラメントの先端領域とは、かしめ接続されたジョイント部を構成し、
前記露出した第１の超電導フィラメントの残りの領域と、前記露出した第２の超電導フィラメントの残りの領域とは、被覆部材を介して接続されたバイパス部を構成し、
前記被覆部材は、前記接続構造体の運転環境下において、前記交流通電用または永久電流スイッチ用の超電導線材の母材よりも電気抵抗率が低い金属材料からなることを特徴とする。 As described above, the superconducting wire connecting structure according to the present invention electrically connects the first superconducting multicore wire and the second superconducting multicore wire having a structure in which a plurality of superconducting filaments are covered with a base material. A connection structure connected to
At least one of the first and second superconducting multicore wires is a superconducting wire for alternating current conduction or a permanent current switch,
A tip region of the first superconducting filament exposed by removing the base material of the first superconducting multicore wire, and a second superconducting filament exposed by removing the base material of the second superconducting multicore wire. The tip region constitutes a joint part that is caulked and connected,
The remaining area of the exposed first superconducting filament and the remaining area of the exposed second superconducting filament constitute a bypass portion connected via a covering member;
The covering member is made of a metal material having an electric resistivity lower than that of the base material of the superconducting wire for the AC energization or the permanent current switch in the operating environment of the connection structure.

また、本発明は、上記の発明に係る超電導線材の接続構造体において、以下のような改良や変更を加えることができる。
（１）前記交流通電用または永久電流スイッチ用の超電導線材の超電導フィラメントがニオブチタン合金であり、該超電導線材の母材が銅ニッケル合金、銅マンガン合金、または銅マンガンニッケル合金のいずれかであり、前記被覆部材が銅、アルミニウム、インジウム、スズ、ビスマス、およびこれらの元素から構成される合金のいずれかである。
（２）前記バイパス部は、前記被覆部材の外周に前記被覆部材と異なる外層部材が更に配設されており、前記外層部材は、前記接続構造体の運転環境下において、前記交流通電用または永久電流スイッチ用の超電導線材の母材よりも熱伝導率が高い金属材料からなる。
（３）前記外層部材が銅、アルミニウム、インジウム、スズ、ビスマス、およびこれらの元素から構成される合金のいずれかである。
（４）前記バイパス部は、前記第１の超電導フィラメントと前記被覆部材との間、および前記第２の超電導フィラメントと前記被覆部材との間に前記被覆部材と異なる中間層が更に配設されており、前記中間層は、前記接続構造体の運転環境下において、前記交流通電用または永久電流スイッチ用の超電導線材の母材よりも電気抵抗率が低い金属材料からなる。
（５）前記中間層が銅、アルミニウム、インジウム、スズ、ビスマス、およびこれらの元素から構成される合金のいずれかである。
（６）前記ジョイント部における前記第１の超電導フィラメントと前記第２の超電導フィラメントとの間に介在超電導体が当接して設けられ、前記介在超電導体は、前記接続構造体の運転環境下において、前記第１および第２の超電導フィラメントよりも低い臨界電流密度を有している。
（７）前記介在超電導体はプレート形状であり、前記介在超電導体の一方の主表面に前記第１の超電導フィラメントが電気的に接続され、前記介在超電導体の他方の主表面に前記第２の超電導フィラメントが電気的に接続されている。
（８）上記の超電導線材の接続構造体を具備する超電導機器である。
（９）上記の超電導線材の接続構造体を具備する核磁気共鳴分析装置または核磁気共鳴画像装置である。 In addition, the present invention can be improved or changed as follows in the superconducting wire connecting structure according to the present invention.
(1) The superconducting filament of the superconducting wire for alternating current or permanent current switch is a niobium titanium alloy, and the base material of the superconducting wire is any one of a copper nickel alloy, a copper manganese alloy, or a copper manganese nickel alloy, The covering member is any one of copper, aluminum, indium, tin, bismuth, and alloys composed of these elements.
(2) In the bypass portion, an outer layer member different from the covering member is further disposed on the outer periphery of the covering member, and the outer layer member is used for the AC energization or permanent in the operating environment of the connection structure. It is made of a metal material having a higher thermal conductivity than the base material of the superconducting wire for the current switch.
(3) The outer layer member is any one of copper, aluminum, indium, tin, bismuth, and an alloy composed of these elements.
(4) In the bypass portion, an intermediate layer different from the covering member is further disposed between the first superconducting filament and the covering member and between the second superconducting filament and the covering member. The intermediate layer is made of a metal material having an electrical resistivity lower than that of the base material of the superconducting wire for the AC energization or permanent current switch in the operating environment of the connection structure.
(5) The intermediate layer is any one of copper, aluminum, indium, tin, bismuth, and an alloy composed of these elements.
(6) An intervening superconductor is provided in contact with the first superconducting filament and the second superconducting filament in the joint portion, and the interposing superconductor is operated under the operating environment of the connection structure. The critical current density is lower than that of the first and second superconducting filaments.
(7) The intervening superconductor has a plate shape, the first superconducting filament is electrically connected to one main surface of the intervening superconductor, and the second main surface of the intervening superconductor is connected to the second main surface. A superconducting filament is electrically connected.
(8) A superconducting device including the connection structure of the superconducting wire.
(9) A nuclear magnetic resonance analyzer or a nuclear magnetic resonance imaging apparatus comprising the above-described superconducting wire connecting structure.

上述の接続構造体に加えて、本発明に係る超電導線材の接続構造体の製造方法は、複数のニオブチタン合金フィラメントが母材に覆われた構造を有する第１の超電導多芯線材と第２の超電導多芯線材とを電気的に接続する接続構造体の製造方法であって、
前記第１および第２の超電導多芯線材のうちの少なくとも一方は、交流通電用または永久電流スイッチ用の超電導線材であり、
前記第１および第２の超電導多芯線材における接続予定領域の前記母材を除去して第１および第２のニオブチタン合金フィラメントを露出させるフィラメント露出工程と、
前記露出した第１および第２のニオブチタン合金フィラメントの先端領域を金属パイプ内に挿入し、前記金属パイプを押圧することによって前記第１および第２のニオブチタン合金フィラメント同士を圧着してジョイント部を形成するジョイント部形成工程と、
前記接続構造体の運転環境下において、前記交流通電用または永久電流スイッチ用の超電導線材の母材よりも電気抵抗率が低い金属材料である被覆部材を、前記露出した第１の超電導フィラメントの残りの領域と、前記露出した第２の超電導フィラメントの残りの領域とに被覆・一体化してバイパス部を形成するバイパス部形成工程とを有することを特徴とする。 In addition to the connection structure described above, the method for manufacturing a connection structure for a superconducting wire according to the present invention includes a first superconducting multicore wire having a structure in which a plurality of niobium titanium alloy filaments are covered with a base material, and a second structure. A method of manufacturing a connection structure for electrically connecting a superconducting multicore wire,
At least one of the first and second superconducting multicore wires is a superconducting wire for alternating current conduction or a permanent current switch,
A filament exposing step of removing the base material in the connection planned region in the first and second superconducting multicore wires to expose the first and second niobium titanium alloy filaments;
The exposed tip region of the first and second niobium titanium alloy filaments is inserted into a metal pipe, and the metal pipe is pressed to crimp the first and second niobium titanium alloy filaments together to form a joint portion. A joint part forming step,
Under the operating environment of the connection structure, a covering member made of a metal material having a lower electrical resistivity than the base material of the superconducting wire for the alternating current conduction or the permanent current switch is left behind the exposed first superconducting filament. And a bypass portion forming step of forming a bypass portion by covering and integrating the exposed region and the remaining region of the exposed second superconducting filament.

また、本発明は、上記の発明に係る超電導線材の接続構造体の製造方法において、以下のような改良や変更を加えることができる。
（１０）前記バイパス部形成工程の後に、前記被覆部材の外周に前記被覆部材と異なる金属材料からなる外層パイプを被せ、前記外層パイプを押圧することによって前記被覆部材と一体化した外層部材を形成する外層部材配設工程を更に有する。 In addition, the present invention can be improved or changed as follows in the method of manufacturing a superconducting wire connection structure according to the present invention.
(10) After the bypass portion forming step, an outer layer pipe made of a metal material different from the covering member is placed on the outer periphery of the covering member, and the outer layer member integrated with the covering member is formed by pressing the outer layer pipe. And an outer layer member disposing step.

（本発明の第１の実施形態）
以下、本発明をより詳細に説明する。はじめに、従来の接続構造体について説明する。図１は、かしめ接続による超電導線材同士の従来の接続構造体の１例を示す斜視模式図である。 (First embodiment of the present invention)
Hereinafter, the present invention will be described in more detail. First, a conventional connection structure will be described. FIG. 1 is a schematic perspective view showing an example of a conventional connection structure between superconducting wires by caulking connection.

図１に示したように、かしめ接続による従来の接続構造体14は、２本の超電導多芯線材4の母材がそれぞれ除去されて露出した超電導フィラメント6（第１の超電導フィラメント61、第２の超電導フィラメント62）が金属パイプ（例えば、無酸素銅パイプ15’）内に挿入され、該金属パイプが押圧変形されて超電導フィラメント6同士が圧着接合されたジョイント部1を有している。ジョイント部1は、超電導フィラメント6同士が直接接合していることから、10-13Ω以下の非常に低い接続抵抗が得られる。 As shown in FIG. 1, the conventional connection structure 14 by caulking connection is such that the superconducting filament 6 (first superconducting filament 61, second superconductor filament 61, second superconductor filament 61, and second superconductor filament) exposed by removing the base materials of the two superconducting multicore wires 4 respectively. The superconducting filament 62) is inserted into a metal pipe (for example, an oxygen-free copper pipe 15 '), and the metal pipe is pressed and deformed to have a joint portion 1 in which the superconducting filaments 6 are joined by pressure bonding. In the joint portion 1, since the superconducting filaments 6 are directly joined to each other, a very low connection resistance of 10 −13 Ω or less can be obtained.

また、従来の接続構造体14では、ジョイント部1近傍の機械的保護やワイヤームーブメントの抑制を目的として、しばしばジョイント部1近傍の超電導多芯線材4がはんだ16で固定される。なお、一般的に、超電導フィラメント6とはんだ16とは濡れ性があまり良くないことから、はんだ固定は主に母材が被覆されている領域（母材が除去されていない領域）で行われる。   Further, in the conventional connection structure 14, the superconducting multi-core wire 4 in the vicinity of the joint portion 1 is often fixed with the solder 16 for the purpose of mechanical protection in the vicinity of the joint portion 1 and suppression of wire movement. In general, the superconducting filament 6 and the solder 16 are not so good in wettability, so that the solder is fixed mainly in a region where the base material is coated (a region where the base material is not removed).

ここで、超電導多芯線材4の母材が共に無酸素銅のような電気抵抗率の低い材料からなる場合には、ジョイント部1で常電導領域（クエンチの芽）が生じた際に、はんだ固定部分がはんだ接続として機能してクエンチの拡大を抑制する効果（すなわち、クエンチ耐性が向上する効果）が期待できる。しかしながら、前述したように、交流通電用や永久電流スイッチ用の超電導線材においては、超電導フィラメント間の電気的結合を抑制するために電気抵抗率が高い母材（例えば、銅ニッケル合金、銅マンガン合金、または銅マンガンニッケル合金）を使用することから、従来の接続構造体14ではクエンチ耐性が極めて弱いことが、本発明者等の調査・研究で確認された（詳細は後述する）。   Here, when both the base materials of the superconducting multi-core wire 4 are made of a material having a low electrical resistivity such as oxygen-free copper, when a normal conduction region (quenching bud) occurs in the joint portion 1, The effect that the fixed portion functions as a solder connection and suppresses the expansion of quenching (that is, the effect of improving quench resistance) can be expected. However, as described above, in a superconducting wire for alternating current conduction or a permanent current switch, a base material having a high electrical resistivity (for example, a copper nickel alloy, a copper manganese alloy, etc.) is used to suppress electrical coupling between superconducting filaments. In addition, it has been confirmed by the present inventors' investigation and research (details will be described later) that the conventional connection structure 14 has extremely low quench resistance.

図２は、本発明に係る超電導線材の接続構造体の１例を示す斜視模式図とバイパス部の断面模式図である。本発明に係る超電導線材の接続構造体11では、２本の超電導多芯線材4（第１の超電導多芯線材41、第２の超電導多芯線材42）のうちの少なくとも一方が交流通電用または永久電流スイッチ用の超電導線材であり、２本の超電導多芯線材4の母材がそれぞれ除去されて露出した超電導フィラメント6の先端領域が金属パイプ15（例えば、無酸素銅パイプ15’）内に挿入され、該金属パイプ15が押圧変形されて超電導フィラメント6同士が圧着接合されたジョイント部1を有している。また、図２に示したように、露出した超電導フィラメント6の残りの領域では、被覆材料5を介して接続されたバイパス部2が形成されている。このとき、被覆材料5は、接続構造体11の運転環境下において、交流通電用または永久電流スイッチ用の超電導線材の母材よりも電気抵抗率が低い金属材料（例えば、銅、アルミニウム、インジウム、スズ、ビスマス、またはこれらの元素から構成される合金）からなる。   FIG. 2 is a schematic perspective view showing an example of a superconducting wire connecting structure according to the present invention and a schematic cross-sectional view of a bypass portion. In the superconducting wire connecting structure 11 according to the present invention, at least one of the two superconducting multicore wires 4 (the first superconducting multicore wire 41 and the second superconducting multicore wire 42) is used for alternating current conduction or A superconducting wire for a permanent current switch, and the tip region of the superconducting filament 6 exposed by removing the base material of the two superconducting multicore wires 4 is in a metal pipe 15 (for example, an oxygen-free copper pipe 15 '). The joint portion 1 is inserted, the metal pipe 15 is pressed and deformed, and the superconducting filaments 6 are joined by pressure bonding. Further, as shown in FIG. 2, a bypass portion 2 connected via a coating material 5 is formed in the remaining region of the exposed superconducting filament 6. At this time, the coating material 5 is a metal material (for example, copper, aluminum, indium, etc.) having an electrical resistivity lower than that of the base material of the superconducting wire for AC conduction or permanent current switch in the operating environment of the connection structure 11. Tin, bismuth, or an alloy composed of these elements).

（接続構造体の製造方法）
本発明に係る超電導線材の接続構造体11の製造プロセスの１例は、次のようなものである。なお、言うまでもなく下記に限定されるものではない。
（i）２本の超電導多芯線材4（第１の超電導多芯線材41、第２の超電導多芯線材42）における接続予定領域の母材を硝酸などで溶解して、超電導フィラメント6（第１の超電導フィラメント61、第２の超電導フィラメント62）を露出させる（フィラメント露出工程）。
（ii）露出させた超電導フィラメント6の先端領域を金属パイプ15内に挿入し、第１の超電導フィラメント61と第２の超電導フィラメント62とをかしめ接続法によって接続してジョイント部1を形成する（ジョイント部形成工程）。
（iii）露出させた超電導フィラメント6の残りの領域に対して被覆部材5を被覆して、被覆部材5と超電導フィラメント6とが一体化したバイパス部2を形成する（バイパス部形成工程）。より具体的には、露出させた超電導フィラメント6の残りの領域の束の外周にスズ、インジウム、ビスマス、またはこれらの合金からなる被覆材料5を被せた後に、その外周に銅またはアルミニウムのパイプを被せ、該パイプを加圧変形させて被覆材料5が超電導フィラメント6間の隙間に十分入り込むようにして一体化する。なお、被覆部材5と超電導フィラメント6とを一体化した後、一体化に用いたパイプを除去してもよいし、除去しなくてもよい。 (Method for manufacturing connection structure)
An example of the manufacturing process of the superconducting wire connecting structure 11 according to the present invention is as follows. Needless to say, it is not limited to the following.
(I) The superconducting filament 6 (first superconducting filament 6 (first superconducting multicore wire 41, first superconducting multicore wire 41, second superconducting multicore wire 42) is dissolved in nitric acid or the like in the region to be connected. The first superconducting filament 61 and the second superconducting filament 62) are exposed (filament exposing step).
(Ii) The exposed tip region of the superconducting filament 6 is inserted into the metal pipe 15, and the first superconducting filament 61 and the second superconducting filament 62 are connected by a caulking connection method to form the joint portion 1 ( Joint part forming step).
(Iii) Covering the remaining region of the exposed superconducting filament 6 with the covering member 5 to form the bypass portion 2 in which the covering member 5 and the superconducting filament 6 are integrated (bypass portion forming step). More specifically, after covering the outer periphery of the bundle of the remaining region of the superconducting filament 6 exposed with a coating material 5 made of tin, indium, bismuth, or an alloy thereof, a copper or aluminum pipe is applied to the outer periphery. Then, the pipe is deformed under pressure so that the coating material 5 is sufficiently integrated into the gap between the superconducting filaments 6 and integrated. Note that after the covering member 5 and the superconducting filament 6 are integrated, the pipe used for the integration may or may not be removed.

（本発明の効果の考察）
次に、本発明の効果について等価回路でモデル化して説明する。図３は、本発明に係る超電導線材の接続構造体を示す等価回路である。図３に示したように、ジョイント部1の抵抗をRjと表記し、バイパス部2の抵抗をRbと表記し、ジョイント部1とバイパス部2とからなる接続構造体ループ3のインダクタンスをLjと表記する。また、２本の超電導多芯線材4（第１の超電導多芯線材41、第２の超電導多芯線材42）に接続される超電導コイルのインダクタンスをLc（一般的には10〜100 H程度）とする。 (Consideration of effects of the present invention)
Next, the effect of the present invention will be described by modeling with an equivalent circuit. FIG. 3 is an equivalent circuit showing a superconducting wire connecting structure according to the present invention. As shown in FIG. 3, the resistance of the joint part 1 is expressed as R j , the resistance of the bypass part 2 is expressed as R b, and the inductance of the connection structure loop 3 composed of the joint part 1 and the bypass part 2 is L j is written. Also, the inductance of the superconducting coil connected to the two superconducting multicore wires 4 (first superconducting multicore wire 41 and second superconducting multicore wire 42) is L c (generally about 10 to 100 H). ).

例えば、接続構造体11に接続された超電導コイル（超電導磁石）を永久電流モード運転で運転する場合を想定する。永久電流モードの定常時には「Rj ＜＜ Rb」であるため、電流はジョイント部1を流れる。ここで、ジョイント部1で常電導領域（クエンチの芽）が生じたとする。このとき、次のような過程に従う。
（a）ジョイント部1における常電導領域の発生に伴ってRjが大きくなりRjNとなる（Rj ＜ RjN）。
（b）「RjN ＞ Rb」となると、ジョイント部1の電流はバイパス部2に移る（Rbは、典型的には10-8〜10-7Ωの程度である）。
（c）ジョイント部1におけるジュール発熱が収まり冷却されるため、ジョイント部1は超電導状態に復帰する（Rj ＜＜ Rb）。
（d）電流が再びジョイント部1に戻る。 For example, it is assumed that the superconducting coil (superconducting magnet) connected to the connection structure 11 is operated in the permanent current mode operation. Since “R j << R b ” in the steady state of the permanent current mode, current flows through the joint portion 1. Here, it is assumed that a normal conducting region (quenching bud) is generated in the joint portion 1. At this time, the following process is followed.
(A) With the occurrence of the normal conducting region in the joint portion 1, R j increases and becomes R jN (R j <R jN ).
(B) When “R jN > R b ”, the current of the joint portion 1 moves to the bypass portion 2 (R b is typically about 10 −8 to 10 −7 Ω).
(C) Since the Joule heat generation in the joint portion 1 is settled and cooled, the joint portion 1 returns to the superconducting state (R j << R b ).
(D) The current returns to the joint 1 again.

上記の過程による超電導磁石における磁場減衰率について説明する。電流がジョイント部1からバイパス部2に移動するのに掛る所要時間Δtj→bは「Δtj→b ＝ Lj/RjN」であり、この間の磁場の減衰時定数τj→bは「τj→b ＝ Lc/RjN」と表わされる。一方、電流がバイパス部2からジョイント部1に復帰するのに掛る所要時間Δtb→jは「Δtb→j ＝ Lj /Rb」であり、この間の磁場の減衰時定数τb→jは「τb→j＝Lc/Rb」と表わされる。したがって、超電導磁石の中心磁束密度は上記（a）〜（d）の過程を経て、式１で与えられる割合で減衰する。なお、B0：初期磁束密度、ΔB：（a）〜（d）過程１サイクルの磁束密度変化量とする。 The magnetic field decay rate in the superconducting magnet by the above process will be described. The time Δt j → b required for the current to move from the joint part 1 to the bypass part 2 is “Δt j → b = L j / R jN ”, and the decay time constant τ j → b of the magnetic field during this time is “ τ j → b = L c / R jN ”. On the other hand, the time Δt b → j required for the current to return from the bypass part 2 to the joint part 1 is “Δt b → j = L j / R b ”, and the decay time constant τ b → j of the magnetic field during this time Is expressed as “τ b → j = L c / R b ”. Therefore, the central magnetic flux density of the superconducting magnet is attenuated at a rate given by Equation 1 through the processes (a) to (d). B 0 : Initial magnetic flux density, ΔB: (a) to (d) The amount of change in magnetic flux density in one cycle of the process.

Figure 0005501258
Figure 0005501258

本発明に係る超電導線材の接続構造体11は、被覆部材5として交流通電用または永久電流スイッチ用の超電導線材の母材よりも電気抵抗率の低い金属材料を用いていることから、バイパス部2の抵抗Rbを小さくすることができる。そのため、バイパス部2に電流が移ったときでもジュール発熱を抑制することができる。また、バイパス部2では、各超電導フィラメント6が熱伝導性に優れた被覆部材5で覆われているため、熱を速やかに逃すことができる。これらの効果によって、バイパス部2におけるクエンチを防止することができる。 Since the superconducting wire connecting structure 11 according to the present invention uses a metal material having a lower electrical resistivity than the base material of the superconducting wire for AC energization or permanent current switch as the covering member 5, the bypass portion 2 The resistance Rb can be reduced. Therefore, Joule heat generation can be suppressed even when the current is transferred to the bypass unit 2. Further, in the bypass portion 2, since each superconducting filament 6 is covered with the covering member 5 having excellent thermal conductivity, heat can be quickly released. With these effects, quenching in the bypass unit 2 can be prevented.

さらに、Lcは前述したように10〜100 Hの程度であり、Ljはジョイント部1とバイパス部2とを十分に近づければ10-9 H程度まで小さくすることができる。よって、式１から概算すると、（a）〜（d）過程１サイクルによる磁場減衰率ΔB/Bは、わずか1 ppb程度である。これは、NMR分析装置やMRI装置の稼働上で問題とならないレベルである。 Furthermore, L c is about 10 to 100 H as described above, and L j can be reduced to about 10 −9 H if the joint portion 1 and the bypass portion 2 are sufficiently brought close to each other. Therefore, when approximated from Equation 1, the magnetic field attenuation rate ΔB / B by one cycle of the steps (a) to (d) is only about 1 ppb. This is a level that does not cause a problem in the operation of the NMR analyzer and the MRI apparatus.

以上のことから、本発明に係る超電導線材の接続構造体は、かしめ接続法で作製したジョイント部で常電導領域が発生してもその拡大が防止され、永久電流モード運転する超電導磁石の中心磁束密度の減衰が微小量に抑制されるという効果がある。言い換えると、本発明に係る超電導線材の接続構造体は、NMR分析装置やMRI装置などの超電導機器での使用に適していると言える。   From the above, the connection structure of the superconducting wire according to the present invention is prevented from expanding even if a normal conduction region is generated in the joint part produced by the caulking connection method, and the central magnetic flux of the superconducting magnet operated in the permanent current mode. There is an effect that the attenuation of the density is suppressed to a minute amount. In other words, it can be said that the superconducting wire connecting structure according to the present invention is suitable for use in superconducting equipment such as an NMR analyzer and an MRI apparatus.

（本発明の第２の実施形態）
図４は、本発明に係る超電導線材の接続構造体の他の１例を示す斜視模式図とバイパス部の断面模式図である。図４に示したように、第２の実施形態に係る接続構造体12は、バイパス部2において、被覆部材5と異なる外層部材7が被覆部材5の外周に配設されている点でのみ第１の実施形態に係る接続構造体11と異なる。外層部材7は、接続構造体の運転環境下において、交流通電用または永久電流スイッチ用の超電導線材の母材よりも熱伝導率が高い金属材料からなり、例えば、銅、アルミニウム、インジウム、スズ、ビスマス、またはこれらの元素から構成される合金が好適に用いられる。 (Second embodiment of the present invention)
FIG. 4 is a perspective schematic view showing another example of a superconducting wire connection structure according to the present invention and a cross-sectional schematic view of a bypass portion. As shown in FIG. 4, the connection structure 12 according to the second embodiment is different from the bypass portion 2 only in that an outer layer member 7 different from the covering member 5 is disposed on the outer periphery of the covering member 5. Different from the connection structure 11 according to the first embodiment. The outer layer member 7 is made of a metal material having higher thermal conductivity than the base material of the superconducting wire for alternating current or permanent current switch under the operating environment of the connection structure, for example, copper, aluminum, indium, tin, Bismuth or an alloy composed of these elements is preferably used.

第２の実施形態に係る接続構造体12は、第１の実施形態に係る接続構造体11と同様の効果に加えて、被覆部材5の外周に外層部材7を配設することでバイパス部2の熱容量が大きくなることから、バイパス部2に電流が移ったときの温度上昇が抑制される。これにより、バイパス部2のクエンチが更に防止される効果がある。   In addition to the same effects as the connection structure 11 according to the first embodiment, the connection structure 12 according to the second embodiment provides the bypass portion 2 by disposing the outer layer member 7 on the outer periphery of the covering member 5. Therefore, the temperature rise when the current is transferred to the bypass unit 2 is suppressed. Thereby, there is an effect that quenching of the bypass unit 2 is further prevented.

（本発明の第３の実施形態）
図５は、本発明に係る超電導線材の接続構造体の他の１例を示す斜視模式図とバイパス部の断面模式図である。図５に示したように、第３の実施形態に係る接続構造体13は、バイパス部2において、被覆部材5と異なる中間層8が被覆部材5と超電導フィラメント6との間に配設されている点でのみ第１の実施形態に係る接続構造体11と異なる。中間層8は、接続構造体の運転環境下において、交流通電用または永久電流スイッチ用の超電導線材の母材よりも電気抵抗率が低い金属材料からなり、例えば、銅、アルミニウム、インジウム、スズ、ビスマス、またはこれらの元素から構成される合金が好適に用いられる。 (Third embodiment of the present invention)
FIG. 5 is a schematic perspective view showing another example of the superconducting wire connecting structure according to the present invention and a schematic cross-sectional view of the bypass portion. As shown in FIG. 5, in the connection structure 13 according to the third embodiment, an intermediate layer 8 different from the covering member 5 is disposed between the covering member 5 and the superconducting filament 6 in the bypass portion 2. It differs from the connection structure 11 according to the first embodiment only in that it is. The intermediate layer 8 is made of a metal material having an electrical resistivity lower than that of the base material of the superconducting wire for alternating current or permanent current switch under the operating environment of the connection structure, for example, copper, aluminum, indium, tin, Bismuth or an alloy composed of these elements is preferably used.

第３の実施形態に係る接続構造体13は、第１の実施形態に係る接続構造体11と同様の効果に加えて、被覆材料5と超電導フィラメント6との間に中間層8を配設することで被覆材料5と超電導フィラメント6との密着性が高まることから、バイパス部2の抵抗Rbを更に低減することができる。なお、中間層8の形成プロセスとしては、例えば、蒸着などの気相成膜法が好適に用いられる。 In addition to the same effects as the connection structure 11 according to the first embodiment, the connection structure 13 according to the third embodiment has an intermediate layer 8 disposed between the coating material 5 and the superconducting filament 6. As a result, the adhesiveness between the coating material 5 and the superconducting filament 6 is increased, so that the resistance Rb of the bypass portion 2 can be further reduced. As the formation process of the intermediate layer 8, for example, a vapor phase film formation method such as vapor deposition is preferably used.

（本発明の第４の実施形態）
図６は、本発明に係る超電導線材の接続構造体のジョイント部の変形例を示す断面模式図である。図６に示したように、第４の実施形態に係るジョイント部1’は、第１の超電導フィラメント61と第２の超電導フィラメント62との間にプレート形状の介在超電導体17が当接して設けられている。また、介在超電導体17は、接続構造体の運転環境下において、第１の超電導フィラメント61および第２の超電導フィラメント62よりも低い臨界電流密度を有している。 (Fourth embodiment of the present invention)
FIG. 6 is a schematic cross-sectional view showing a modification of the joint portion of the connection structure of the superconducting wire according to the present invention. As shown in FIG. 6, the joint portion 1 ′ according to the fourth embodiment is provided with a plate-shaped intercalating superconductor 17 in contact between the first superconducting filament 61 and the second superconducting filament 62. It has been. The intervening superconductor 17 has a lower critical current density than the first superconducting filament 61 and the second superconducting filament 62 under the operating environment of the connection structure.

超電導線材は、一般的に、使用環境における最大経験磁場でその臨界電流がある程度のマージンを持つように設計される（または、そうなるように機器（例えば超電導コイル）を設計する）。一方、超電導線材同士の接続構造体は、設置場所の空間的な制約や超電導安定性の観点から、低磁場領域に設置されることが通常である。そのため、接続構造体の設置される低磁場領域では、接続構造体内の超電導フィラメントが運転電流に対して過大な臨界電流を有することになり、多数の超電導フィラメントの内の極一部を利用するだけで運転電流を輸送することが可能と考えられる。そのため、時間が経過するにつれて、超電導フィラメント6間の電流分布は良好な接合界面を有する超電導フィラメントのみに偏っていくと考えられる。その結果、クエンチの芽が生じた時に、過度の偏流に起因した大きなジュール熱が起こり易いと考えられる。   A superconducting wire is generally designed such that its critical current has some margin at the maximum empirical magnetic field in the environment of use (or the device (eg, superconducting coil) is designed to do so). On the other hand, the connection structure between the superconducting wires is usually installed in a low magnetic field region from the viewpoint of spatial restriction of the installation location and superconducting stability. Therefore, in the low magnetic field region where the connection structure is installed, the superconducting filament in the connection structure has an excessive critical current with respect to the operating current, and only a part of the poles among the many superconducting filaments is used. It is considered possible to transport the operating current at Therefore, as time passes, the current distribution between the superconducting filaments 6 is considered to be biased only to the superconducting filaments having a good bonding interface. As a result, it is considered that when Jolt buds are generated, large Joule heat due to excessive drift is likely to occur.

上述したように、第４の実施形態に係るジョイント部1’では、第１および第２の超電導フィラメント61，62の間に該超電導フィラメントよりも低い臨界電流密度を有する介在超電導体17を配設しているため、介在超電導体17の臨界電流密度の制約により輸送電流が超電導フィラメント6の極一部に偏流することを抑制し、均等な電流分布に近づく。その結果、輸送電流における過度の偏流に起因する大きなジュール熱を抑制し、ジョイント部におけるクエンチの発生を抑制することができる効果がある。なお、言うまでもなく、第４の実施形態は前述の第１〜第３の実施形態のいずれとも組み合わせることができる。   As described above, in the joint portion 1 ′ according to the fourth embodiment, the intervening superconductor 17 having a lower critical current density than the superconducting filament is disposed between the first and second superconducting filaments 61 and 62. For this reason, the transport current is prevented from drifting to a part of the pole of the superconducting filament 6 due to the limitation of the critical current density of the interposing superconductor 17, and the current distribution approaches an even current distribution. As a result, there is an effect that it is possible to suppress large Joule heat due to excessive drift in the transport current and to suppress the occurrence of quenching in the joint portion. Needless to say, the fourth embodiment can be combined with any of the first to third embodiments described above.

以下、実施例により本発明の具体例を説明する。なお、本発明は以下の実施例に限定されるものではない。   Hereinafter, specific examples of the present invention will be described by way of examples. In addition, this invention is not limited to a following example.

図７は、超電導線材の接続構造体の通電特性を測定するためのサンプル形状を示す模式図である。図７に示したように、測定サンプルは２本の超電導多芯線材4から構成されている。第１の超電導多芯線材41は、超電導フィラメント6の材質がニオブチタン合金であり、母材の材質が無酸素銅である。第２の超電導多芯線材42は、超電導フィラメント6の材質がニオブチタン合金であり、母材の材質が銅ニッケル合金（Cu-10mass％Ni）である。第１の超電導多芯線材41は途中にループ部を形成し、第２の超電導多芯線材42は直状のままとした。また、ループ部を挟んで互いに反対側の２箇所で接続構造体を形成して第１の超電導多芯線材41と第２の超電導多芯線材42とを接続した。なお、第１の超電導多芯線材41と第２の超電導多芯線材42とは、母材の材質以外は同じ構成とした。   FIG. 7 is a schematic diagram showing a sample shape for measuring the current-carrying characteristics of the superconducting wire connecting structure. As shown in FIG. 7, the measurement sample is composed of two superconducting multi-core wires 4. In the first superconducting multi-core wire 41, the material of the superconducting filament 6 is a niobium titanium alloy, and the material of the base material is oxygen-free copper. In the second superconducting multi-core wire 42, the material of the superconducting filament 6 is a niobium titanium alloy, and the material of the base material is a copper nickel alloy (Cu-10 mass% Ni). The first superconducting multicore wire 41 formed a loop part in the middle, and the second superconducting multicore wire 42 remained straight. Further, a connection structure was formed at two locations opposite to each other across the loop portion, and the first superconducting multicore wire 41 and the second superconducting multicore wire 42 were connected. The first superconducting multicore wire 41 and the second superconducting multicore wire 42 have the same configuration except for the material of the base material.

比較例１として、従来の接続構造体14（図１参照）を次のような手順で作製した。第１および第２の超電導多芯線材41，42のそれぞれ両端部35 mmを硝酸に浸漬して母材を溶解し、超電導フィラメントを露出させた。次に、露出した第１および第２の超電導フィラメント61，62を重ねて無酸素銅パイプ15’（肉厚5 mm、長さ25 mm）に挿入した。該無酸素銅パイプ15’を一軸加圧して潰すことで、無酸素銅パイプ15’内で２つの超電導フィラメント61，62を一体化（圧着）させたジョイント部1を形成した。また、母材を除去した境界から25 mm長さで２本の超電導多芯線材41，42の母材同士をはんだ16で固定した。   As Comparative Example 1, a conventional connection structure 14 (see FIG. 1) was produced by the following procedure. Each of the first and second superconducting multi-core wires 41 and 42 was immersed in nitric acid at both end portions 35 mm to dissolve the base material, thereby exposing the superconducting filament. Next, the exposed first and second superconducting filaments 61 and 62 were stacked and inserted into an oxygen-free copper pipe 15 '(thickness 5 mm, length 25 mm). The oxygen-free copper pipe 15 'was uniaxially pressed and crushed to form the joint portion 1 in which the two superconducting filaments 61 and 62 were integrated (crimped) in the oxygen-free copper pipe 15'. In addition, the base materials of the two superconducting multi-core wires 41 and 42 having a length of 25 mm from the boundary from which the base material was removed were fixed with solder 16.

実施例１として、第２の実施形態に係る接続構造体12’（図８参照）を次のような手順で作製した。図８は、本発明に係る実施例１を示す斜視模式図とバイパス部の断面模式図である。第１および第２の超電導多芯線材41，42のそれぞれ両端部50 mmを硝酸に浸漬して母材を溶解し、超電導フィラメントを露出させた。次に、露出した第１および第２の超電導フィラメント61，62を重ね、露出した超電導フィラメントの先端領域（先端からの距離が0〜25 mmの領域）を無酸素銅パイプ15’（肉厚5 mm、長さ25 mm）に挿入した。該無酸素銅パイプ15’を一軸加圧して潰すことで、無酸素銅パイプ15’内で２つの超電導フィラメント61，62を一体化（圧着）させたジョイント部1を形成した。   As Example 1, a connection structure 12 ′ (see FIG. 8) according to the second embodiment was produced by the following procedure. FIG. 8 is a schematic perspective view showing the first embodiment according to the present invention and a schematic cross-sectional view of the bypass portion. Each of the first and second superconducting multicore wires 41 and 42 was immersed in nitric acid at 50 mm on both ends to dissolve the base material to expose the superconducting filament. Next, the exposed first and second superconducting filaments 61 and 62 are stacked, and the tip region of the exposed superconducting filament (region having a distance from the tip of 0 to 25 mm) is connected to an oxygen-free copper pipe 15 ′ (thickness 5). mm, length 25 mm). The oxygen-free copper pipe 15 'was uniaxially pressed and crushed to form the joint portion 1 in which the two superconducting filaments 61 and 62 were integrated (crimped) in the oxygen-free copper pipe 15'.

次に、露出した第１および第２の超電導フィラメント61，62の残りの領域（先端からの距離が25〜50 mmの領域）に被覆部材5’としてインジウムシートを巻き付けた。巻き付けたインジウムシートの外周に予め挿入しておいた無酸素銅パイプ15”（肉厚5 mm、長さ25 mm）を被せた。その後、インジウムの被覆部材5’が各超電導フィラメント6の隙間に十分入り込むように該無酸素銅パイプ15”を一軸加圧して潰してバイパス部2を形成した。   Next, an indium sheet was wound as a covering member 5 ′ on the remaining regions of the exposed first and second superconducting filaments 61 and 62 (regions having a distance from the tip of 25 to 50 mm). An oxygen-free copper pipe 15 ”(5 mm thick, 25 mm long) previously inserted was placed on the outer periphery of the wound indium sheet. After that, the indium covering member 5 ′ was placed in the gap between each superconducting filament 6. The oxygen-free copper pipe 15 ″ was uniaxially pressed and crushed so as to sufficiently enter, thereby forming the bypass portion 2.

上記で作製した測定サンプルの通電特性は、次のようにして測定した。図９は、超電導線材の接続構造体の通電特性を測定するための試験系を示す模式図である。図９に示したように、クライオスタット20内に誘導コイル21、サンプルヒータ22、ホール素子23から構成される試験系を組み、測定サンプルのループ部が誘導コイル21の領域内に入るように測定サンプルを設置した。クライオスタット20内に液体ヘリウムを満たして次の手順で測定サンプルに通電した。   The energization characteristics of the measurement sample prepared above were measured as follows. FIG. 9 is a schematic diagram showing a test system for measuring the current-carrying characteristics of the superconducting wire connection structure. As shown in FIG. 9, a test system composed of an induction coil 21, a sample heater 22, and a hall element 23 is assembled in the cryostat 20, and the measurement sample is placed so that the loop portion of the measurement sample enters the region of the induction coil 21. Was installed. The cryostat 20 was filled with liquid helium, and the measurement sample was energized in the following procedure.

まず、サンプルヒータ22を加熱し、測定サンプルの一部（超電導多芯線材4の一部）の超電導性を消失させた。この状態で誘導コイル21に通電し、測定サンプルのループ部を貫通するように磁束を発生させた。次に、サンプルヒータ22の加熱を止めて測定サンプルの超電導性を復帰させた後、誘導コイル21の通電を止めると測定サンプルのループ部内の磁束が保存されるように超電導多芯線材4に電流が流れる。このとき、ループ部の中心磁束密度をホール素子23で計測し、その時間変化を記録した。   First, the sample heater 22 was heated, and the superconductivity of a part of the measurement sample (part of the superconducting multicore wire 4) was lost. In this state, the induction coil 21 was energized, and a magnetic flux was generated so as to penetrate the loop portion of the measurement sample. Next, after heating of the sample heater 22 is stopped and the superconductivity of the measurement sample is restored, when the energization of the induction coil 21 is stopped, a current is supplied to the superconducting multi-core wire 4 so that the magnetic flux in the loop portion of the measurement sample is preserved. Flows. At this time, the center magnetic flux density of the loop portion was measured by the Hall element 23, and the change with time was recorded.

図１０は、比較例１の通電特性の結果（捕捉した磁束の時間変化）の１例を示すチャートである。図１０に示したように、測定開始から約300秒経過時に中心磁束密度の不連続な減少が突然起こった。これは、従来の接続構造体14においてクエンチが発生し、測定サンプルに保持されていた磁気エネルギーがジュール熱となって消失したためと考えられた。このときの磁場減衰率は約90％であった。   FIG. 10 is a chart showing an example of a result of energization characteristics of Comparative Example 1 (time change of captured magnetic flux). As shown in FIG. 10, a discontinuous decrease in the central magnetic flux density suddenly occurred after about 300 seconds from the start of measurement. This was thought to be because quenching occurred in the conventional connection structure 14 and the magnetic energy held in the measurement sample disappeared as Joule heat. The magnetic field decay rate at this time was about 90%.

図１１は、実施例１の通電特性の結果（捕捉した磁束の時間変化）の１例を示すチャートである。図１１に示したように、測定開始から約1500秒経過時に中心磁束密度の不連続な減少が突然起こった。これも、第２の実施形態に係る接続構造体12’においてクエンチが発生したことに起因すると考えられた。ただし、このときの磁場減衰率はわずか1％程度であった。なお、他の実施形態に係る接続構造体においても、同様の結果が得られることを別途確認した。   FIG. 11 is a chart showing an example of a result of energization characteristics of Example 1 (change in captured magnetic flux with time). As shown in FIG. 11, a discontinuous decrease in the center magnetic flux density suddenly occurred after about 1500 seconds from the start of measurement. This was also thought to be due to the occurrence of quenching in the connection structure 12 'according to the second embodiment. However, the magnetic field attenuation rate at this time was only about 1%. In addition, it confirmed separately that the same result was obtained also in the connection structure which concerns on other embodiment.

上記の結果を図３に示した等価回路で考察する。測定サンプルのインダクタンスは10-7 H程度であり、ジョイント部1とバイパス部2とからなるループ3のインダクタンスは10-9 H程度である。これらインダクタンスと電気抵抗率とを式１に代入して計算すると、実施例１に関しては磁場減衰率がよく一致した。すなわち、図３の等価回路で説明したモデルの現象が起きていると考えられた。また、この接続構造体12’を一般的な超電導磁石（10〜100 H）に適用したとすると、式１からその磁場減衰率は0.1 ppb程度となることが示唆される。これは、NMR分析装置やMRI装置で要求されるレベルを十分満足している。 The above results will be considered with the equivalent circuit shown in FIG. The inductance of the measurement sample is about 10 −7 H, and the inductance of the loop 3 including the joint portion 1 and the bypass portion 2 is about 10 −9 H. When these inductance and electrical resistivity were substituted into Equation 1, the magnetic field attenuation rate for Example 1 was in good agreement. That is, the model phenomenon described in the equivalent circuit of FIG. 3 is considered to have occurred. Further, if this connection structure 12 ′ is applied to a general superconducting magnet (10 to 100 H), it is suggested from Equation 1 that the magnetic field attenuation rate is about 0.1 ppb. This sufficiently satisfies the level required for NMR analyzers and MRI apparatuses.

一方、比較例１に関しては、式１の結果と一致しなかった。これは、ジョイント部1で常電導領域が生じてはんだ固定部に電流が移った際、はんだ固定部におけるジュール発熱が大き過ぎて熱拡散が追い付かず、はんだ固定部の温度が上昇して測定サンプル全体にクエンチが進展したためと考えられた。   On the other hand, Comparative Example 1 did not agree with the result of Formula 1. This is because when a normal conduction region occurs in the joint part 1 and current flows to the solder fixing part, Joule heat generation in the solder fixing part is too large to catch up with heat diffusion, and the temperature of the solder fixing part rises and the measurement sample This was thought to be due to the progress of quenching throughout.

以上説明したように、本発明に係る超電導線材の接続構造体は、ジョイント部1で常電導領域（クエンチの芽）が発生してもその拡大が防止され、永久電流モード運転する超電導磁石の磁場減衰率を極小に抑制できるという効果を実証した。すなわち、低い接続抵抗と高いクエンチ耐性とを兼ね備えていると言える。そのため、本発明に係る超電導線材の接続構造体は、NMR分析装置やMRI装置をはじめとして、大型超電導マグネット、電力貯蔵装置、磁気分離装置、磁気浮上列車、超電導発電機、核融合炉用マグネットなどの超電導機器に適用可能である。   As described above, the connection structure of the superconducting wire according to the present invention is prevented from expanding even if a normal conduction region (quenching bud) occurs in the joint portion 1, and the magnetic field of the superconducting magnet operated in the permanent current mode. The effect that the attenuation rate can be suppressed to the minimum was demonstrated. That is, it can be said that it has both low connection resistance and high quench resistance. Therefore, the superconducting wire connection structure according to the present invention includes an NMR analyzer, an MRI apparatus, a large superconducting magnet, a power storage device, a magnetic separation device, a magnetic levitation train, a superconducting generator, a fusion reactor magnet, etc. It can be applied to superconducting equipment.

1，1’… ジョイント部、2…バイパス部、
3…ジョイント部とバイパス部とからなる接続構造体ループ、
4…超電導多芯線材、41…第１の超電導多芯線材、42…第２の超電導多芯線材、
5，5’…被覆部材、6…超電導フィラメント、
61…第１の超電導フィラメント、62…第２の超電導フィラメント、
7…外層部材、8…中間層、11，12，12’，13，14…接続構造体、
15…金属パイプ、15’，15”…無酸素銅パイプ、16…はんだ、17…介在超電導体、
20…クライオスタット、21…誘導コイル、22…サンプルヒータ、23…ホール素子。 1, 1 '... Joint part, 2 ... Bypass part,
3. Connection structure loop consisting of joint part and bypass part,
4 ... Superconducting multicore wire, 41 ... First superconducting multicore wire, 42 ... Second superconducting multicore wire,
5,5 '... covering member, 6 ... superconducting filament,
61 ... first superconducting filament, 62 ... second superconducting filament,
7 ... outer layer member, 8 ... intermediate layer, 11, 12, 12 ', 13, 14 ... connection structure,
15 ... metal pipe, 15 ', 15 "... oxygen-free copper pipe, 16 ... solder, 17 ... intervening superconductor,
20 ... Cryostat, 21 ... Induction coil, 22 ... Sample heater, 23 ... Hall element.

Claims (12)

複数の超電導フィラメントが母材に覆われた構造を有する第１の超電導多芯線材と第２の超電導多芯線材とを電気的に接続する接続構造体であって、
前記第１および第２の超電導多芯線材のうちの少なくとも一方は、交流通電用または永久電流スイッチ用の超電導線材であり、
前記第１の超電導多芯線材の母材が除去されて露出した第１の超電導フィラメントの先端領域と、前記第２の超電導多芯線材の母材が除去されて露出した第２の超電導フィラメントの先端領域とは、かしめ接続されたジョイント部を構成し、
前記露出した第１の超電導フィラメントの残りの領域と、前記露出した第２の超電導フィラメントの残りの領域とは、被覆部材を介して接続されたバイパス部を構成し、
前記被覆部材は、前記接続構造体の運転環境下において、前記交流通電用または永久電流スイッチ用の超電導線材の母材よりも電気抵抗率が低い金属材料からなることを特徴とする超電導線材の接続構造体。 A connection structure for electrically connecting a first superconducting multicore wire and a second superconducting multicore wire having a structure in which a plurality of superconducting filaments are covered with a base material,
At least one of the first and second superconducting multicore wires is a superconducting wire for alternating current conduction or a permanent current switch,
A tip region of the first superconducting filament exposed by removing the base material of the first superconducting multicore wire, and a second superconducting filament exposed by removing the base material of the second superconducting multicore wire. The tip region constitutes a joint part that is caulked and connected,
The remaining area of the exposed first superconducting filament and the remaining area of the exposed second superconducting filament constitute a bypass portion connected via a covering member;
The covering member is made of a metal material having an electric resistivity lower than that of the base material of the superconducting wire for the alternating current conduction or the permanent current switch under the operating environment of the connection structure. Structure. 請求項１に記載の超電導線材の接続構造体において、
前記交流通電用または永久電流スイッチ用の超電導線材の超電導フィラメントがニオブチタン合金であり、
該超電導線材の母材が銅ニッケル合金、銅マンガン合金、または銅マンガンニッケル合金のいずれかであり、
前記被覆部材が銅、アルミニウム、インジウム、スズ、ビスマス、およびこれらの元素から構成される合金のいずれかであることを特徴とする超電導線材の接続構造体。 In the connection structure of the superconducting wire according to claim 1,
The superconducting filament of the superconducting wire for the AC energization or permanent current switch is a niobium titanium alloy,
The base material of the superconducting wire is either a copper nickel alloy, a copper manganese alloy, or a copper manganese nickel alloy,
The superconducting wire connecting structure, wherein the covering member is one of copper, aluminum, indium, tin, bismuth, and an alloy composed of these elements. 請求項１または請求項２に記載の超電導線材の接続構造体において、
前記バイパス部は、前記被覆部材の外周に前記被覆部材と異なる外層部材が更に配設されており、
前記外層部材は、前記接続構造体の運転環境下において、前記交流通電用または永久電流スイッチ用の超電導線材の母材よりも熱伝導率が高い金属材料からなることを特徴とする超電導線材の接続構造体。 In the connection structure of the superconducting wire according to claim 1 or 2,
The bypass portion is further provided with an outer layer member different from the covering member on the outer periphery of the covering member,
The outer layer member is made of a metal material having a higher thermal conductivity than the base material of the superconducting wire for the AC current supply or the permanent current switch under the operating environment of the connection structure. Structure. 請求項３に記載の超電導線材の接続構造体において、
前記外層部材が銅、アルミニウム、インジウム、スズ、ビスマス、およびこれらの元素から構成される合金のいずれかであることを特徴とする超電導線材の接続構造体。 In the connection structure of the superconducting wire according to claim 3,
A superconducting wire connecting structure, wherein the outer layer member is one of copper, aluminum, indium, tin, bismuth, and an alloy composed of these elements. 請求項１乃至請求項４のいずれかに記載の超電導線材の接続構造体において、
前記バイパス部は、前記第１の超電導フィラメントと前記被覆部材との間、および前記第２の超電導フィラメントと前記被覆部材との間に前記被覆部材と異なる中間層が更に配設されており、
前記中間層は、前記接続構造体の運転環境下において、前記交流通電用または永久電流スイッチ用の超電導線材の母材よりも電気抵抗率が低い金属材料からなることを特徴とする超電導線材の接続構造体。 In the connection structure of the superconducting wire according to any one of claims 1 to 4,
The bypass portion is further provided with an intermediate layer different from the covering member between the first superconducting filament and the covering member and between the second superconducting filament and the covering member,
The intermediate layer is made of a metal material having an electrical resistivity lower than that of the base material of the superconducting wire for the alternating current conduction or the permanent current switch under the operating environment of the connection structure. Structure. 請求項５に記載の超電導線材の接続構造体において、
前記中間層が銅、アルミニウム、インジウム、スズ、ビスマス、およびこれらの元素から構成される合金のいずれかであることを特徴とする超電導線材の接続構造体。 In the connection structure of the superconducting wire according to claim 5,
A connection structure for a superconducting wire, wherein the intermediate layer is one of copper, aluminum, indium, tin, bismuth, and an alloy composed of these elements. 請求項１乃至請求項６のいずれかに記載の超電導線材の接続構造体において、
前記ジョイント部における前記第１の超電導フィラメントと前記第２の超電導フィラメントとの間に介在超電導体が当接して設けられ、
前記介在超電導体は、前記接続構造体の運転環境下において、前記第１および第２の超電導フィラメントよりも低い臨界電流密度を有していることを特徴とする超電導線材の接続構造体。 In the connection structure of the superconducting wire according to any one of claims 1 to 6,
An interposed superconductor is provided in contact with the first superconducting filament and the second superconducting filament in the joint portion,
A superconducting wire connecting structure, wherein the intervening superconductor has a lower critical current density than the first and second superconducting filaments in an operating environment of the connecting structure. 請求項７に記載の超電導線材の接続構造体において、
前記介在超電導体はプレート形状であり、
前記介在超電導体の一方の主表面に前記第１の超電導フィラメントが電気的に接続され、前記介在超電導体の他方の主表面に前記第２の超電導フィラメントが電気的に接続されていることを特徴とする超電導線材の接続構造体。 In the connection structure of the superconducting wire according to claim 7,
The intervening superconductor is plate-shaped,
The first superconducting filament is electrically connected to one main surface of the intervening superconductor, and the second superconducting filament is electrically connected to the other main surface of the interposing superconductor. A superconducting wire connection structure. 請求項１乃至請求項８のいずれかに記載の超電導線材の接続構造体を具備していることを特徴とする超電導機器。   A superconducting device comprising the connection structure for a superconducting wire according to any one of claims 1 to 8. 請求項１乃至請求項８のいずれかに記載の超電導線材の接続構造体を具備していることを特徴とする核磁気共鳴分析装置または磁気共鳴画像装置。   A nuclear magnetic resonance analyzer or a magnetic resonance imaging apparatus comprising the superconducting wire connecting structure according to any one of claims 1 to 8. 複数のニオブチタン合金フィラメントが母材に覆われた構造を有する第１の超電導多芯線材と第２の超電導多芯線材とを電気的に接続する接続構造体の製造方法であって、
前記第１および第２の超電導多芯線材のうちの少なくとも一方は、交流通電用または永久電流スイッチ用の超電導線材であり、
前記第１および第２の超電導多芯線材における接続予定領域の前記母材を除去して第１および第２のニオブチタン合金フィラメントを露出させるフィラメント露出工程と、
前記露出した第１および第２のニオブチタン合金フィラメントの先端領域を金属パイプ内に挿入し、前記金属パイプを押圧変形することによって前記第１および第２のニオブチタン合金フィラメント同士を圧着してジョイント部を形成するジョイント部形成工程と、
前記接続構造体の運転環境下において、前記交流通電用または永久電流スイッチ用の超電導線材の母材よりも電気抵抗率が低い金属材料である被覆部材を、前記露出した第１の超電導フィラメントの残りの領域と、前記露出した第２の超電導フィラメントの残りの領域とに被覆・一体化してバイパス部を形成するバイパス部形成工程とを有することを特徴とする超電導線材の接続構造体の製造方法。 A method for producing a connection structure for electrically connecting a first superconducting multicore wire having a structure in which a plurality of niobium titanium alloy filaments are covered with a base material and a second superconducting multicore wire,
At least one of the first and second superconducting multicore wires is a superconducting wire for alternating current conduction or a permanent current switch,
A filament exposing step of removing the base material in the connection planned region in the first and second superconducting multicore wires to expose the first and second niobium titanium alloy filaments;
Inserting the exposed tip regions of the first and second niobium titanium alloy filaments into a metal pipe and pressing and deforming the metal pipe, the first and second niobium titanium alloy filaments are crimped together to form a joint portion. A joint part forming step to be formed;
Under the operating environment of the connection structure, a covering member made of a metal material having a lower electrical resistivity than the base material of the superconducting wire for the alternating current conduction or the permanent current switch is left behind the exposed first superconducting filament. And a bypass portion forming step of forming a bypass portion by covering and integrating the region and the remaining region of the exposed second superconducting filament. A method for manufacturing a connection structure of a superconducting wire. 請求項１１に記載の超電導線材の接続構造体の製造方法において、
前記バイパス部形成工程の後に、前記被覆部材の外周に前記被覆部材と異なる金属材料からなる外層パイプを被せ、前記外層パイプを押圧することによって前記被覆部材と一体化した外層部材を形成する外層部材配設工程を更に有することを特徴とする超電導線材の接続構造体の製造方法。 In the manufacturing method of the connection structure of the superconducting wire according to claim 11,
After the bypass portion forming step, an outer layer member formed by covering the outer periphery of the covering member with an outer layer pipe made of a metal material different from the covering member and pressing the outer layer pipe to form an outer layer member integrated with the covering member The manufacturing method of the connection structure of a superconducting wire characterized by further having an arrangement process.
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