JP2016178111A

JP2016178111A - Current lead

Info

Publication number: JP2016178111A
Application number: JP2015054886A
Authority: JP
Inventors: 秀夫菅根; Hideo Sugane; 康雄引地; Yasuo Hikichi; 昌啓箕輪; Masahiro Minowa; 敬塩原; Kei Shiohara; 足立　和久; Kazuhisa Adachi; 和久足立
Original assignee: SWCC Showa Cable Systems Co Ltd
Current assignee: SWCC Corp
Priority date: 2015-03-18
Filing date: 2015-03-18
Publication date: 2016-10-06
Anticipated expiration: 2035-03-18
Also published as: JP6484471B2

Abstract

PROBLEM TO BE SOLVED: To provide a current lead which can prevent the reduction in work efficiency due to the installation of a reinforcement cylinder and has high reliability and stable characteristics.SOLUTION: A current lead includes: a low temperature-side electrode; a normal temperature-side electrode; a thermoelectric element; and a reinforcement cylinder which is fixed to an element unit including the electrodes and the element and surrounds the periphery of a junction part including a low temperature-side junction part between the thermoelectric element and the low temperature-side electrode and a normal temperature-side junction part between the thermoelectric element and the normal temperature-side electrode. The reinforcement cylinder has a notch window on a part of the peripheral surface.SELECTED DRAWING: Figure 4

Description

本発明は、低温部に設置される超電導応用機器と常温部に設置される外部機器を接続する電流リードに関し、特に熱電変換素子を用いた熱電冷却型の電流リードに関する。 The present invention relates to a current lead for connecting a superconducting application device installed in a low temperature part and an external device installed in a room temperature part, and more particularly to a thermoelectric cooling type current lead using a thermoelectric conversion element.

近年、超電導ケーブルや超電導マグネット等、超電導を利用した超電導応用機器の分野では、実用化に向けてさかんに研究、開発が行われている。一般に、超電導応用機器は低温部（低温容器）に設置され、常温部に設置された外部機器（例えば電源）と、電流リードを介して接続される。超電導応用機器の運転は、極低温環境下で行われるため、低温部の断熱性が極めて重要となる。低温部の断熱性が悪く、低温部への熱侵入が大きいと、超電導応用機器の冷却効率が低下して超電導状態を維持するための冷却コストが増大することとなり、場合によっては超電導応用機器を運転できなくなってしまう。この低温部への熱侵入の経路としては、低温容器を伝熱する経路、又は電流リードを伝熱する経路が考えられる。 In recent years, in the field of superconducting applied equipment using superconductivity such as superconducting cables and superconducting magnets, research and development have been conducted for practical use. In general, a superconducting application device is installed in a low temperature part (low temperature container) and connected to an external device (for example, a power source) installed in the normal temperature part via a current lead. Since the operation of superconducting equipment is performed in a cryogenic environment, the heat insulation of the low temperature part is extremely important. If the heat insulation property of the low temperature part is poor and the heat penetration into the low temperature part is large, the cooling efficiency of the superconducting application equipment will decrease and the cooling cost for maintaining the superconducting state will increase. It becomes impossible to drive. As a path of heat penetration into the low temperature portion, a path for transferring heat through the low temperature container or a path for transferring heat through the current leads can be considered.

低温容器を介した熱侵入を防止するための手法としては、液体窒素等の冷媒及び超電導応用機器を収容する冷媒槽と、冷媒槽の外側に設けられる真空槽とを有する二重構造の低温容器が知られている。この低温容器によれば、真空断熱により低温部への熱侵入が低減される。 As a technique for preventing heat intrusion through a cryogenic vessel, a dual-structure cryogenic vessel having a refrigerant tank containing a refrigerant such as liquid nitrogen and a superconducting application device and a vacuum tank provided outside the refrigerant vessel It has been known. According to this low-temperature container, heat penetration into the low-temperature part is reduced by vacuum insulation.

電流リードを介した熱侵入を防止するための手法としては、酸化物超電導体を用いた超電導電流リードが提案されている。酸化物超電導体は、金属導体に比較して電気抵抗が小さく、かつ熱伝導率が小さいため（銅の数１０分の１）、超電導電流リードにおけるジュール熱の発生はなく、低温部への伝熱量も極めて小さい。したがって、超電導電流リードによれば、低温部への熱侵入が低減される。しかし、超電導電流リードを採用する場合、電流リードの超電導状態を維持できる様に冷却設備を設けなければならず、冷却コストが増大してしまうという課題がある。 As a technique for preventing heat intrusion through the current lead, a superconducting current lead using an oxide superconductor has been proposed. Oxide superconductors have lower electrical resistance and lower thermal conductivity than metal conductors (a few tenths of copper), so there is no Joule heat generation in the superconducting current leads, and transmission to the low temperature part. The amount of heat is very small. Therefore, according to the superconducting current lead, heat penetration into the low temperature portion is reduced. However, when a superconducting current lead is employed, a cooling facility must be provided so that the superconducting state of the current lead can be maintained, and there is a problem that the cooling cost increases.

そこで、電流リードを介した熱侵入を防止するための他の手法として、熱電変換素子（以下「ペルチェ素子」と称する）を利用した熱電冷却型電流リードが提案されている（例えば特許文献１〜３）。熱電冷却型電流リードにおいては、低温部の超電導応用機器に接続される低温側電極と、常温部の外部機器に接続される常温側電極とが、ペルチェ素子を介して接続される。具体的には、低温側電極とペルチェ素子の一端面が半田により接合され、同様に、ペルチェ素子の他端面と常温側電極が半田により接合される。以下において、低温側電極と常温側電極を区別しない場合は、単に電極と称することとする。 Therefore, thermoelectric cooling type current leads using thermoelectric conversion elements (hereinafter referred to as “Peltier elements”) have been proposed as other methods for preventing heat intrusion via current leads (for example, Patent Documents 1 to 3). 3). In a thermoelectric cooling type current lead, a low temperature side electrode connected to a superconducting application device in a low temperature part and a normal temperature side electrode connected to an external device in a normal temperature part are connected via a Peltier element. Specifically, one end face of the low temperature side electrode and the Peltier element are joined by solder, and similarly, the other end face of the Peltier element and the room temperature side electrode are joined by solder. Hereinafter, when the low temperature side electrode and the normal temperature side electrode are not distinguished, they are simply referred to as electrodes.

ペルチェ素子は、通電したときに一端側から吸熱し、他端側から放熱する機能を有する。ペルチェ素子は、例えばＢｉＴｅ（ビスマス−テルル）系の化合物半導体で構成される。ペルチェ素子がｐ型半導体で構成される場合は、電流の流入側で吸熱が生じ、流出側で発熱が生じる。逆に、ペルチェ素子がｎ型半導体で構成される場合は、電流の流入側で発熱が生じ、流出側で吸熱が生じる。したがって、熱電冷却型電流リードにおける通電方向に応じて、ｐ型半導体又はｎ型半導体で構成されるペルチェ素子を用いることで、通電時に低温部から常温部に向けて熱を移動させることができるので、低温部への熱侵入が低減される。 The Peltier element has a function of absorbing heat from one end side and releasing heat from the other end side when energized. The Peltier device is made of, for example, a BiTe (bismuth-tellurium) -based compound semiconductor. When the Peltier element is made of a p-type semiconductor, heat is absorbed on the current inflow side and heat is generated on the outflow side. Conversely, when the Peltier element is composed of an n-type semiconductor, heat is generated on the current inflow side and heat is absorbed on the outflow side. Therefore, by using a Peltier element composed of a p-type semiconductor or an n-type semiconductor according to the energization direction in the thermoelectrically cooled current lead, heat can be transferred from the low temperature portion to the normal temperature portion during energization. , Heat penetration into the low temperature part is reduced.

上述したように、ペルチェ素子と電極とは半田付けにより接合されるので、接合強度が低く破損しやすい。そのため、電流リードの設置時などに、意図しない外力が接合部に直接加わらないように、接合部の周囲には補強筒が配置される。この場合、ペルチェ素子及び電極を含む素子ユニット（例えば電極）が補強筒に固定されるため、使用時に熱応力が生じてペルチェ効果が低下したり、ペルチェ素子が破損したりする虞がある。そのため、可撓性を有するフレキシブル導体を利用して、熱応力がフレキシブル導体によって吸収され、ペルチェ素子に加わらないようになっている（例えば特許文献２）。 As described above, since the Peltier element and the electrode are joined by soldering, the joining strength is low and they are easily damaged. Therefore, a reinforcing cylinder is arranged around the joint so that unintended external force is not directly applied to the joint when the current lead is installed. In this case, since an element unit (for example, an electrode) including a Peltier element and an electrode is fixed to the reinforcing cylinder, there is a possibility that a thermal stress is generated during use and the Peltier effect is lowered or the Peltier element is damaged. Therefore, using a flexible conductor having flexibility, thermal stress is absorbed by the flexible conductor and is not applied to the Peltier element (for example, Patent Document 2).

特開２００４−６８５９号公報JP 2004-6859 A 特開２０１３−１０５９０６号公報JP 2013-105906 A 特開２０１４−１０３３２４号公報JP 2014-103324 A

従来は、強度向上の効果を最大限に得るために、補強筒として完全な円筒体のものが適用され、補強筒の内部が閉空間となっている。このような補強筒では、電流リードが真空槽内に配置される場合に、補強筒の内部のガスを一気に排気することはできない（少量ずつ漏れ出す）ため、補強筒を用いない電流リードに比較して、真空排気に時間を要するという問題がある。また、接合部の周囲が完全に覆われているために、電流リードに不具合が生じた際、接合部の外観を容易に観察することができない。すなわち、接合部を観察するためには、補強筒を取り外す必要があり、取外し作業を慎重に行わなければ、接合部に応力が加わり破損を招く虞もある。このように、電流リードに補強筒を設けることは、強度を向上する点からは有効であるが、作業効率が低下するという課題が生じる。 Conventionally, in order to obtain the effect of improving the strength to the maximum, a complete cylindrical body is applied as the reinforcing cylinder, and the inside of the reinforcing cylinder is a closed space. In such a reinforcing cylinder, when the current lead is arranged in the vacuum chamber, the gas inside the reinforcing cylinder cannot be exhausted at a stretch (leaks out little by little), so compared to the current lead that does not use the reinforcing cylinder Therefore, there is a problem that it takes time to evacuate. Further, since the periphery of the joint is completely covered, the appearance of the joint cannot be easily observed when a problem occurs in the current lead. That is, in order to observe the joint portion, it is necessary to remove the reinforcing cylinder, and unless the removal operation is performed carefully, stress may be applied to the joint portion and damage may occur. Thus, providing the reinforcing cylinder on the current lead is effective from the viewpoint of improving the strength, but there arises a problem that the working efficiency is lowered.

本発明の目的は、補強筒を設けることに伴い作業効率が低下するのを防止でき、安定した特性を有する信頼性の高い電流リードを提供することである。 An object of the present invention is to provide a highly reliable current lead having stable characteristics that can prevent a reduction in work efficiency due to provision of a reinforcing cylinder.

本発明に係る電流リードは、低温部に設置される超電導応用機器と常温部に設置される外部機器とを接続する電流リードであって、
前記超電導応用機器に接続される低温側電極と、
前記外部機器に接続される常温側電極と、
一方の面に前記低温側電極が接合され、他方の面に前記常温側電極が接合される熱電変換素子と、
前記熱電変換素子、前記低温側電極、及び前記常温側電極を含む素子ユニットに固定され、前記熱電変換素子と前記低温側電極との低温側接合部、及び前記熱電変換素子と前記常温側電極との常温側接合部を含む接合部の周囲を取り囲む補強筒と、を備え、
前記補強筒は、周面の一部に、切欠窓を有することを特徴とする。 The current lead according to the present invention is a current lead for connecting a superconducting application device installed in a low temperature part and an external device installed in a room temperature part,
A low temperature side electrode connected to the superconducting application device;
A room temperature side electrode connected to the external device;
A thermoelectric conversion element in which the low temperature side electrode is bonded to one surface and the room temperature side electrode is bonded to the other surface;
Fixed to an element unit including the thermoelectric conversion element, the low temperature side electrode, and the room temperature side electrode, a low temperature side junction between the thermoelectric conversion element and the low temperature side electrode, and the thermoelectric conversion element and the room temperature side electrode. A reinforcing cylinder surrounding the periphery of the joint including the room temperature side joint of
The reinforcing cylinder has a cutout window in a part of the peripheral surface.

本発明によれば、補強筒を設けることに伴い作業効率が低下するのを防止できるとともに、接合部の外観観察を容易に行うことができる。したがって、安定した特性を有する信頼性の高い電流リードが提供される。 According to the present invention, it is possible to prevent the work efficiency from being lowered due to the provision of the reinforcing cylinder, and it is possible to easily observe the appearance of the joint portion. Therefore, a highly reliable current lead having stable characteristics is provided.

本発明の一実施の形態に係る電流リードを用いた超電導磁石装置の一例を示す図である。It is a figure which shows an example of the superconducting magnet apparatus using the current lead which concerns on one embodiment of this invention. 実施の形態に係る電流リードの詳細な構成を示す図である。It is a figure which shows the detailed structure of the current lead which concerns on embodiment. ペルチェ素子と低温側電極及び常温側電極との接合部を示す図である。It is a figure which shows the junction part of a Peltier device, a low temperature side electrode, and a normal temperature side electrode. 補強筒を示す図である。It is a figure which shows a reinforcement cylinder. 低温側電極を示す図である。It is a figure which shows a low temperature side electrode.

以下、本発明の実施の形態を図面に基づいて詳細に説明する。
図１は、本発明の一実施の形態に係る電流リード１０を用いた超電導磁石装置１を示す図である。図１に示すように、超電導磁石装置１は、低温部に設置される超電導コイル１１と、常温部に設置される電源１２と、電源１２と超電導コイル１１を電気的に接続する電流リード１０を備える。２つの電流リード１０を区別する場合は、電流リード１０Ａ、１０Ｂと称する。 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a diagram showing a superconducting magnet device 1 using a current lead 10 according to an embodiment of the present invention. As shown in FIG. 1, the superconducting magnet device 1 includes a superconducting coil 11 installed in a low temperature part, a power supply 12 installed in a room temperature part, and a current lead 10 that electrically connects the power supply 12 and the superconducting coil 11. Prepare. When the two current leads 10 are distinguished, they are referred to as current leads 10A and 10B.

超電導コイル１１は、例えば、端末容器１４内に設置された真空断熱構造を有する低温容器１３内に収容され、液体ヘリウムによって冷却される。電源１２は、超電導コイル１１を励磁するのに必要な電流を、電流リード１０を介して供給する。 The superconducting coil 11 is accommodated in, for example, a cryogenic container 13 having a vacuum heat insulating structure installed in the terminal container 14 and cooled by liquid helium. The power source 12 supplies a current necessary for exciting the superconducting coil 11 via the current lead 10.

電流リード１０は、ペルチェ効果を利用した熱電冷却型の電流リードである。電流リード１０は、ペルチェ素子１０１、低温側電極１０２、及び常温側電極１０３を備える。低温側電極１０２、常温側電極１０３は、電気抵抗の面からＣｕ含有量が９０重量％以上であることが好ましく、例えば純度９９．９９％以上の無酸素銅で構成される。 The current lead 10 is a thermoelectric cooling type current lead utilizing the Peltier effect. The current lead 10 includes a Peltier element 101, a low temperature side electrode 102, and a normal temperature side electrode 103. The low temperature side electrode 102 and the normal temperature side electrode 103 preferably have a Cu content of 90% by weight or more from the viewpoint of electrical resistance, and are made of oxygen-free copper having a purity of 99.99% or more, for example.

ペルチェ素子１０１の一方の面に低温側電極１０２が接合され、他方の面に常温側電極１０３が接合される。低温側電極１０２は超電導コイル１１に接続され、常温側電極１０３は電源１２に接続される。電流リード１０と超電導コイル１１、及び電流リード１０と電源１２は、例えば銅リード１５、１６によって接続される。 The low temperature side electrode 102 is bonded to one surface of the Peltier element 101, and the normal temperature side electrode 103 is bonded to the other surface. The low temperature side electrode 102 is connected to the superconducting coil 11, and the normal temperature side electrode 103 is connected to the power source 12. The current lead 10 and the superconducting coil 11 and the current lead 10 and the power source 12 are connected by, for example, copper leads 15 and 16.

ペルチェ素子１０１には、室温以下の低温において、性能指数Ｚ（＝α²／（κρ）、α：ゼーベック係数、κ：熱伝導率、ρ：比抵抗）の値が最大となるように組成が調整された半導体を使用することが好ましい。ペルチェ素子１０１は、例えばＢｉＴｅ系、ＢｉＴｅＳｂ系、又はＢｉＳｂ系の化合物半導体で構成される。 The composition of the Peltier element 101 is such that the values of the figure of merit Z (= α ² / (κρ), α: Seebeck coefficient, κ: thermal conductivity, ρ: specific resistance) are maximized at a low temperature below room temperature. It is preferable to use a conditioned semiconductor. The Peltier device 101 is made of, for example, a BiTe-based, BiTeSb-based, or BiSb-based compound semiconductor.

特に、熱電変換効率の面から、Ｔｅ含有量が５〜５０重量％であるＢｉＴｅ系半導体又はＢｉＴｅＳｂ系半導体が好適である。ＢｉＴｅ系半導体又はＢｉＴｅＳｂ系半導体を適用した場合、常温から２００Ｋ付近までの温度範囲で良好な冷却能力が得られる。また、ＢｉＳｂ系半導体を適用した場合、２００Ｋ付近から液体窒素温度（７７Ｋ）付近までの温度範囲で良好な冷却能力が得られる。 In particular, from the viewpoint of thermoelectric conversion efficiency, a BiTe-based semiconductor or BiTeSb-based semiconductor having a Te content of 5 to 50% by weight is preferable. When a BiTe-based semiconductor or BiTeSb-based semiconductor is applied, a good cooling capacity can be obtained in a temperature range from room temperature to around 200K. In addition, when a BiSb-based semiconductor is applied, a good cooling capacity can be obtained in a temperature range from around 200K to around liquid nitrogen temperature (77K).

電源１２の正極側に接続される電流リード１０Ａのペルチェ素子１０１にはｎ型半導体が適用され、負極側に接続される電流リード１０Ｂのペルチェ素子１０１にはｐ型半導体が適用される。例えば、ＢｉＴｅ系半導体の導電型は、ＳｂＩ₃を添加することによりｎ型に制御され、ＰｂＩ₃を添加することによりｐ型に制御される。また、構成元素の量を化学量論比からわずかにずらすことによって、ＢｉＴｅ系半導体の導電型を制御することもできる。 An n-type semiconductor is applied to the Peltier element 101 of the current lead 10A connected to the positive side of the power supply 12, and a p-type semiconductor is applied to the Peltier element 101 of the current lead 10B connected to the negative side. For example, the conductivity type of BiTe-based semiconductor is controlled in n-type by adding SbI _3, it is controlled in p-type by adding PbI _3. In addition, the conductivity type of the BiTe semiconductor can be controlled by slightly shifting the amount of the constituent element from the stoichiometric ratio.

電流リード１０Ａ、１０Ｂにおいては、ペルチェ素子１０１の低温側で吸熱が生じ、常温側で発熱が生じる。すなわち、ペルチェ素子１０１において、通電時に低温側から常温側に向けて熱が移動するので、低温部への熱侵入が低減され、超電導コイル１１を効率よく冷却することができる。 In the current leads 10A and 10B, heat absorption occurs on the low temperature side of the Peltier element 101, and heat generation occurs on the normal temperature side. That is, in the Peltier element 101, heat is transferred from the low temperature side to the normal temperature side when energized, so that heat penetration into the low temperature part is reduced and the superconducting coil 11 can be efficiently cooled.

端末容器１４は、例えば有底円筒形状を有し、上部の開口に電流リード固定用フランジユニット２０（以下「フランジユニット２０」と称する）が取り付けられる。端末容器１４は密閉され、超伝導磁石装置１の使用時（通電時）には、真空に排気される。 The terminal container 14 has, for example, a bottomed cylindrical shape, and a current lead fixing flange unit 20 (hereinafter referred to as a “flange unit 20”) is attached to an upper opening. The terminal container 14 is hermetically sealed and is evacuated to vacuum when the superconducting magnet device 1 is used (when energized).

フランジユニット２０は、固定フランジ２０１及び輻射熱防止板２０２（常温側バッフル板２０２Ａ及び低温側バッフル板２０２Ｂ）を有する。固定フランジ２０１には、輻射熱防止板２０２を固定するためのシャフト２０３（常温側バッフル板用シャフト２０３Ａ及び低温側バッフル板用シャフト２０３Ｂ）が垂設される。低温側バッフル板用シャフト２０３Ｂは、常温側バッフル板２０２Ａの貫通穴（図示略）に挿通される。低温側バッフル板用シャフト２０３Ｂの外径は、常温側バッフル板２０２Ａの貫通穴の内径よりも小さく、互いに接触しない、すなわち直接熱伝導が行われないようになっている。 The flange unit 20 includes a fixed flange 201 and a radiant heat prevention plate 202 (a normal temperature side baffle plate 202A and a low temperature side baffle plate 202B). Shafts 203 (room temperature side baffle plate shaft 203A and low temperature side baffle plate shaft 203B) for fixing the radiant heat prevention plate 202 are suspended from the fixing flange 201. The low temperature side baffle plate shaft 203B is inserted into a through hole (not shown) of the normal temperature side baffle plate 202A. The outer diameter of the low temperature side baffle plate shaft 203B is smaller than the inner diameter of the through hole of the normal temperature side baffle plate 202A, and is not in contact with each other, that is, direct heat conduction is not performed.

常温側バッフル板用シャフト２０３Ａ及び低温側バッフル板用シャフト２０３Ｂは、例えば同一円周上に等間隔で複数本設けられる。常温側バッフル板用シャフト２０３Ａの一端が固定フランジ２０１に固定され、他端には常温側バッフル板２０２Ａが固定される。低温側バッフル板用シャフト２０３Ｂの一端が固定フランジ２０１に固定され、他端には低温側バッフル板２０２Ｂが固定される。 A plurality of room temperature side baffle plate shafts 203A and low temperature side baffle plate shafts 203B are provided, for example, at equal intervals on the same circumference. One end of the room temperature side baffle plate shaft 203A is fixed to the fixing flange 201, and the other end of the room temperature side baffle plate 202A is fixed. One end of the low temperature side baffle plate shaft 203B is fixed to the fixing flange 201, and the low temperature side baffle plate 202B is fixed to the other end.

固定フランジ２０１は、電流リード１０の取り付け位置に貫通穴（図示略）を有する。この貫通穴に電流リード１０が挿通され、常温側電極１０３が外部に露出した状態で固定フランジ２０１に固定される。同様に、常温側バッフル板２０２Ａ及び低温側バッフル板２０２Ｂは、電流リード１０の取り付け位置に、電流リード１０の外径よりも大径の貫通穴（図示略）を有する。固定フランジ２０１に電流リード１０が取り付けられる際、電流リード１０は常温側バッフル板２０２Ａ及び低温側バッフル板２０２Ｂの貫通穴に挿通される。 The fixing flange 201 has a through hole (not shown) at a position where the current lead 10 is attached. The current lead 10 is inserted into the through hole, and the room temperature side electrode 103 is fixed to the fixing flange 201 in a state exposed to the outside. Similarly, the normal temperature side baffle plate 202 </ b> A and the low temperature side baffle plate 202 </ b> B have through holes (not shown) having a diameter larger than the outer diameter of the current lead 10 at the mounting position of the current lead 10. When the current lead 10 is attached to the fixed flange 201, the current lead 10 is inserted into the through holes of the normal temperature side baffle plate 202A and the low temperature side baffle plate 202B.

ペルチェ素子１０１と低温側電極１０２との接合部Ｊ１（以下「低温側接合部Ｊ１」と称する）及びペルチェ素子１０１と常温側電極１０３との接合部Ｊ２（以下「常温側接合部Ｊ２」と称する）を含む接合部Ｊは、端末容器１４内に収容される。電流リード１０とフランジユニット２０を合わせて「電流リード付きフランジユニット」と称する。 A junction J1 between the Peltier element 101 and the low temperature side electrode 102 (hereinafter referred to as “low temperature side junction J1”) and a junction J2 between the Peltier element 101 and the room temperature side electrode 103 (hereinafter referred to as “room temperature side junction J2”). ) Including the joint member J is accommodated in the terminal container 14. The current lead 10 and the flange unit 20 are collectively referred to as a “flange unit with a current lead”.

常温側バッフル板２０２Ａは、低温側接合部Ｊ１よりも低温側に位置する。低温側バッフル板２０３は、低温側バッフル板２０２よりも低温側に位置する。電流リード１０に通電したとき、低温側接合部Ｊ１及び常温側接合部Ｊ２においてジュール熱が生じるが、このジュール熱の低温側への輻射は常温側バッフル板２０２Ａ及び低温側バッフル板２０２Ｂにより遮断される。そして、常温側バッフル板用シャフト２０３Ａ及び低温側バッフル板用シャフト２０３Ｂを通じて、固定フランジ２０１に伝達され、放熱される。 The room temperature side baffle plate 202A is located on the lower temperature side than the low temperature side joint J1. The low temperature side baffle plate 203 is located on the lower temperature side than the low temperature side baffle plate 202. When the current lead 10 is energized, Joule heat is generated in the low temperature side joint J1 and the room temperature side joint J2, and the radiation of the Joule heat to the low temperature side is blocked by the room temperature side baffle plate 202A and the low temperature side baffle plate 202B. The And it is transmitted to the fixed flange 201 through the room temperature side baffle plate shaft 203A and the low temperature side baffle plate shaft 203B, and is radiated.

固定フランジ２０１、常温側バッフル板２０２Ａ、低温側バッフル板２０２Ｂ、常温側バッフル板用シャフト２０３Ａ、及び低温側バッフル板用シャフト２０３Ｂは、例えばガラス繊維をプラスチックに混入して強度を向上させたガラス繊維強化プラスチック（ＧＦＲＰ：Glass Fiber Reinforced Plastics）で形成される。ＧＦＲＰ製のものを用いることにより、輻射熱の流入を効果的に遮断することができる。 The fixing flange 201, the room temperature side baffle plate 202A, the low temperature side baffle plate 202B, the room temperature side baffle plate shaft 203A, and the low temperature side baffle plate shaft 203B are made of glass fiber whose strength is improved by mixing glass fiber with plastic, for example. It is made of reinforced plastic (GFRP: Glass Fiber Reinforced Plastics). By using a product made of GFRP, the inflow of radiant heat can be effectively blocked.

図２は、実施の形態に係る電流リード１０の詳細な構成を示す図である。図３は、ペルチェ素子１０１と低温側電極１０２及び常温側電極１０３との接合部Ｊを示す図である。図３Ａは接合部Ｊの側面図であり、図３Ｂは図３ＡにおけるＡ矢視断面図である。図４は、補強筒１０４を示す図である。図４Ａは補強筒１０４の側面図であり、図４Ｂは図４ＡにおけるＢ矢視断面図である。図５は、低温側電極１０２を示す図である。図５Ａは低温側電極１０２の側面図（フレキシブル導体接続前）であり、図５Ｂは図５ＡにおけるＣ矢視平面図である。図５Ｃはフレキシブル導体１０６を接続した後のかしめ部１０２ｃを示す平面図である。 FIG. 2 is a diagram illustrating a detailed configuration of the current lead 10 according to the embodiment. FIG. 3 is a view showing a joint J between the Peltier element 101 and the low temperature side electrode 102 and the normal temperature side electrode 103. 3A is a side view of the joint J, and FIG. 3B is a cross-sectional view taken along arrow A in FIG. 3A. FIG. 4 is a view showing the reinforcing cylinder 104. 4A is a side view of the reinforcing cylinder 104, and FIG. 4B is a cross-sectional view taken along arrow B in FIG. 4A. FIG. 5 is a diagram showing the low temperature side electrode 102. FIG. 5A is a side view of the low temperature side electrode 102 (before connection of the flexible conductor), and FIG. 5B is a plan view as viewed in the direction of arrow C in FIG. 5A. FIG. 5C is a plan view showing the caulking portion 102c after the flexible conductor 106 is connected.

図２に示すように、電流リード１０は、ペルチェ素子１０１、低温側電極１０２、常温側電極１０３、及び補強筒１０４を備える。電流リード１０の構成要素であるペルチェ素子１０１、低温側電極１０２、及び常温側電極１０３が配列される方向（図２において上下方向）を「軸方向」、軸方向に直交する方向を「径方向」と称する。 As shown in FIG. 2, the current lead 10 includes a Peltier element 101, a low temperature side electrode 102, a normal temperature side electrode 103, and a reinforcing cylinder 104. The direction (vertical direction in FIG. 2) in which the Peltier element 101, the low temperature side electrode 102, and the normal temperature side electrode 103, which are the components of the current lead 10, are arranged is “axial direction”, and the direction orthogonal to the axial direction is “radial direction”. ".

また、電流リード１０は、低温側電極１０２のさらに低温側（軸方向下側）に、低温側補助電極１０５を備える。低温側電極１０２と低温側補助電極１０５は可撓性を有するフレキシブル導体１０６によって接続される。電流リード１０において、補強筒１０４が固定される部分、すなわちペルチェ素子１０１、低温側電極１０２、常温側電極１０３、低温側補助電極１０５、及びフレキシブル導体１０６を含む部分を「素子ユニット」と称する。 The current lead 10 further includes a low temperature side auxiliary electrode 105 on the low temperature side (lower side in the axial direction) of the low temperature side electrode 102. The low temperature side electrode 102 and the low temperature side auxiliary electrode 105 are connected by a flexible conductor 106 having flexibility. A portion of the current lead 10 to which the reinforcing cylinder 104 is fixed, that is, a portion including the Peltier element 101, the low temperature side electrode 102, the normal temperature side electrode 103, the low temperature side auxiliary electrode 105, and the flexible conductor 106 is referred to as an “element unit”.

ペルチェ素子１０１は、例えば複数の円柱形状又は角柱形状を有し、低温側電極１０２及び常温側電極１０３によって挟持された状態で固定される。ペルチェ素子１０１は、１つであってもよいし、複数であってもよい。ここでは、低温側電極１０２と常温側電極１０３との間に１４個のペルチェ素子１０１が配置されているものとする（図３参照）。 The Peltier element 101 has, for example, a plurality of columnar shapes or prismatic shapes, and is fixed in a state of being sandwiched between the low temperature side electrode 102 and the normal temperature side electrode 103. There may be one Peltier element 101 or a plurality of Peltier elements 101. Here, it is assumed that 14 Peltier elements 101 are arranged between the low temperature side electrode 102 and the normal temperature side electrode 103 (see FIG. 3).

低温側電極１０２は、図５に示すように、略円柱形状のペルチェ固定部１０２ａ、ペルチェ固定部１０２ａよりも大径のフランジ部１０２ｂ、及びかしめ部１０２ｃを有する。ペルチェ固定部１０２ａの端面にペルチェ素子１０１の一方の面が接合される。フランジ部１０２ｂは軸方向に貫通する貫通孔１０２ｇを有し、この貫通孔１０２ｇに電極固定ボルト１０８が挿通される。 As shown in FIG. 5, the low temperature side electrode 102 has a substantially cylindrical Peltier fixing part 102a, a flange part 102b having a diameter larger than that of the Peltier fixing part 102a, and a caulking part 102c. One surface of the Peltier element 101 is joined to the end surface of the Peltier fixing portion 102a. The flange portion 102b has a through hole 102g penetrating in the axial direction, and the electrode fixing bolt 108 is inserted into the through hole 102g.

かしめ部１０２ｃは、軸方向に形成された導体挿入口１０２ｆを有する。かしめ部１０２ｃは、導体挿入口１０２ｆにフレキシブル導体１０６の一端が挿入された状態で平面加圧される。かしめ部１０２ｃが塑性変形することにより、低温側電極１０２とフレキシブル導体１０６とがかしめにより接続される。適切に平面加圧を行うためには、かしめ部１０２ｃのかしめ治具と当接する面（図５Ｂにおけるかしめ部１０２ｃの左右の面）は平坦であることが好ましい。 The caulking portion 102c has a conductor insertion opening 102f formed in the axial direction. The caulking portion 102c is plane-pressurized with one end of the flexible conductor 106 inserted into the conductor insertion opening 102f. When the caulking portion 102c is plastically deformed, the low temperature side electrode 102 and the flexible conductor 106 are connected by caulking. In order to perform the flat surface pressure appropriately, it is preferable that the surfaces (the left and right surfaces of the caulking portion 102c in FIG. 5B) that come into contact with the caulking jig of the caulking portion 102c are flat.

かしめ部１０２ｃの径方向断面（図５Ｂ参照）において、導体挿入口１０２ｆは略矩形状を有し、かしめ方向（図５の左右方向）に片寄って配置される。フランジ部１０２ｂとかしめ部１０２ｃの境界部分において、導体挿入口１０２ｆに対応する部分には、切欠溝１０２ｅが形成される。かしめ部１０２ｃの一部（導体挿入口１０２ｆが形成されている部分）は、かしめ方向と直交する方向に膨出する（図５Ｃ参照）。導体挿入口１０２ｆをかしめ方向に片寄って配置することにより、フランジ部１０２ｂとかしめ部１０２ｃの連結部分の長さを確保することができるので、切欠溝１０２ｅを形成しても、強度が著しく低下することはない。 In the radial cross section of the caulking portion 102c (see FIG. 5B), the conductor insertion opening 102f has a substantially rectangular shape and is arranged to be offset in the caulking direction (left-right direction in FIG. 5). A cutout groove 102e is formed in a portion corresponding to the conductor insertion opening 102f at the boundary portion between the flange portion 102b and the caulking portion 102c. A part of the caulking portion 102c (the portion where the conductor insertion opening 102f is formed) bulges in a direction orthogonal to the caulking direction (see FIG. 5C). By arranging the conductor insertion opening 102f so as to be offset in the caulking direction, it is possible to secure the length of the connecting portion between the flange portion 102b and the caulking portion 102c. Therefore, even if the notch groove 102e is formed, the strength is significantly reduced. There is nothing.

図５Ｃに示す状態において、フレキシブル導体１０６の占積率は、５０％以上であることが好ましく、より好ましくは７０％以上である。これにより、接続抵抗が低く抑えられ、ジュール熱の発生を抑制できるので、電流リード１０を介した熱侵入を低減することができる。また、所定の接続強度が確保されるので、耐久性にも優れる。占積率とは、かしめ部１０２ｃの断面積におけるフレキシブル導体１０６が占める割合である。占積率は、例えば導体挿入口１０２ｆの形状、大きさ、及びかしめ時の加圧力により調整することができる。 In the state shown in FIG. 5C, the space factor of the flexible conductor 106 is preferably 50% or more, and more preferably 70% or more. As a result, the connection resistance is kept low and the generation of Joule heat can be suppressed, so that heat penetration through the current lead 10 can be reduced. Moreover, since predetermined connection strength is ensured, it is excellent also in durability. The space factor is a ratio occupied by the flexible conductor 106 in the cross-sectional area of the caulking portion 102c. The space factor can be adjusted by, for example, the shape and size of the conductor insertion opening 102f and the pressure applied during caulking.

また、低温側電極１０２は、ペルチェ固定部１０２ａの端面の周縁部に沿って、軸方向に突出する突出枠部１０２ｄを有する（図３参照）。すなわち、ペルチェ素子１０１が配置される部分は、凹部となっている。なお、突出枠部１０２ｄは、ペルチェ素子１０１が配置される部分を取り囲むように形成されていればよく、ペルチェ固定部１０２ａの端面の周縁部に沿って形成されていなくてもよい。 Moreover, the low temperature side electrode 102 has the protrusion frame part 102d which protrudes in an axial direction along the peripheral part of the end surface of the Peltier fixing | fixed part 102a (refer FIG. 3). That is, the portion where the Peltier element 101 is disposed is a recess. Note that the protruding frame portion 102d only needs to be formed so as to surround the portion where the Peltier element 101 is disposed, and may not be formed along the peripheral edge portion of the end surface of the Peltier fixing portion 102a.

突出枠部１０２ｄの幅Ｗは、素子接合面の外径Ｄの３％よりも小さいと、突出枠部１０２ｄの強度が低く、加工性も悪くなる。一方、突出枠部１０２ｄの幅Ｗが素子接合面の外径Ｄの５％よりも大きいと、通電容量を考慮して電極径（素子接合面の外径Ｄ）を最適化した場合にペルチェ素子１０１の配置領域を確保できなくなる。したがって、突出枠部１０２ｄの幅Ｗは、低温側電極１０２の素子接合面の外径Ｄの３〜５％であることが好ましい。 If the width W of the protruding frame portion 102d is smaller than 3% of the outer diameter D of the element bonding surface, the strength of the protruding frame portion 102d is low, and the workability is deteriorated. On the other hand, when the width W of the protruding frame portion 102d is larger than 5% of the outer diameter D of the element bonding surface, the Peltier element is optimized when the electrode diameter (outer diameter D of the element bonding surface) is optimized in consideration of the current carrying capacity. The arrangement area 101 cannot be secured. Therefore, the width W of the protruding frame portion 102d is preferably 3 to 5% of the outer diameter D of the element bonding surface of the low temperature side electrode 102.

突出枠部１０２ｄの高さＨは、高すぎると、強度低下に繋がり、加工性も悪くなる。また引っ掛かりやすくなるために取扱性も低下する。したがって、突出枠部１０２ｄの高さＨは、極端に高くする必要はなく、溶融半田が乗り越えて流出しない程度であればよい。 If the height H of the protruding frame portion 102d is too high, it leads to a decrease in strength and the workability also deteriorates. Moreover, since it becomes easy to catch, handling property also falls. Therefore, the height H of the projecting frame portion 102d does not need to be extremely high, and may be as long as the molten solder gets over and does not flow out.

常温側電極１０３は、略円柱形状のペルチェ固定部１０３ａ、ペルチェ固定部１０３ａよりも大径のフランジ部１０３ｂ、及び胴部１０３ｃを有する。ペルチェ固定部１０３ａの端面にペルチェ素子１０１の他方の面が接合される。フランジ部１０３ｂは軸方向に貫通する貫通孔（図示略）を有し、この貫通孔に電極固定ボルト１０９が挿通される。また、フランジ部１０３ｂは、径方向に形成されるボルト固定穴（図示略）を有し、このボルト固定穴に補強筒固定ボルト１１３が螺合される。胴部１０３ｃは、フランジユニット２０の固定フランジ２０１の貫通穴に挿通され、この状態でシール金具１１４が取り付けられる。フランジ固定ナット１１５が胴部１０３ｃの雄ねじ部（図示略）に螺合され、シール金具１１４を介して固定フランジ２０１に締め付けられることにより、電流リード１０は固定フランジ２０１に固定される。 The room temperature side electrode 103 includes a substantially cylindrical Peltier fixing part 103a, a flange part 103b having a larger diameter than the Peltier fixing part 103a, and a body part 103c. The other surface of the Peltier element 101 is joined to the end surface of the Peltier fixing portion 103a. The flange portion 103b has a through hole (not shown) penetrating in the axial direction, and the electrode fixing bolt 109 is inserted into the through hole. The flange portion 103b has a bolt fixing hole (not shown) formed in the radial direction, and the reinforcing cylinder fixing bolt 113 is screwed into the bolt fixing hole. The trunk portion 103c is inserted into the through hole of the fixed flange 201 of the flange unit 20, and the seal fitting 114 is attached in this state. The flange fixing nut 115 is screwed into a male screw portion (not shown) of the body portion 103 c and is fastened to the fixing flange 201 via the seal fitting 114, whereby the current lead 10 is fixed to the fixing flange 201.

また、常温側電極１０３は、低温側電極１０２と同様に、ペルチェ固定部１０３ａの端面の周縁部に沿って、軸方向に突出する突出枠部１０３ｄを有する（図３参照）。すなわち、ペルチェ素子１０１が配置される部分は、凹部となっている。なお、突出枠部１０３ｄは、ペルチェ素子１０１が配置される部分を取り囲むように形成されていればよく、ペルチェ固定部１０３ａの端面の周縁部に沿って形成されていなくてもよい。 Similarly to the low temperature side electrode 102, the normal temperature side electrode 103 has a protruding frame portion 103d protruding in the axial direction along the peripheral edge portion of the end face of the Peltier fixing portion 103a (see FIG. 3). That is, the portion where the Peltier element 101 is disposed is a recess. The protruding frame portion 103d only needs to be formed so as to surround a portion where the Peltier element 101 is disposed, and may not be formed along the peripheral edge portion of the end surface of the Peltier fixing portion 103a.

ペルチェ素子１０１と低温側電極１０２、及びペルチェ素子１０１と常温側電極１０３は、例えば半田付けにより接合される。この場合に用いられる半田としては、Ｓｎ含有量が９０〜９９重量％であるＳｎ−Ａｇ−Ｃｕ（いわゆる鉛フリー半田）が耐熱性の面から好適である。半田付けにより所定の接合強度を確保するため、ペルチェ素子１０１は、両端面（低温側電極１０２及び常温側電極１０３との接合面）に、Ｎｉめっき層を有することが好ましい。また、低温側電極１０２、常温側電極１０３は、ペルチェ素子１０１との接合面に、Ａｇめっき層を有することが好ましい。 The Peltier element 101 and the low temperature side electrode 102, and the Peltier element 101 and the normal temperature side electrode 103 are joined by soldering, for example. As the solder used in this case, Sn—Ag—Cu (so-called lead-free solder) having a Sn content of 90 to 99% by weight is preferable from the viewpoint of heat resistance. In order to ensure a predetermined bonding strength by soldering, the Peltier element 101 preferably has Ni plating layers on both end surfaces (bonding surfaces between the low temperature side electrode 102 and the normal temperature side electrode 103). Moreover, it is preferable that the low temperature side electrode 102 and the normal temperature side electrode 103 have an Ag plating layer on the joint surface with the Peltier element 101.

低温側電極１０２及び常温側電極１０３によってペルチェ素子を挟持した状態で、低温側電極１０２の貫通孔１０２ｇに電極固定ボルト１０８が挿通され、連結スペーサー１０７に螺合される。また、常温側電極１０３の貫通孔（図示略）に電極固定ボルト１０９が挿通され、連結スペーサー１０７に螺合される。このとき、低温側電極１０２とペルチェ素子１０１との間及び常温側電極１０３とペルチェ素子１０１との間には、所定厚さの半田が配置される。 In a state where the Peltier element is sandwiched between the low temperature side electrode 102 and the normal temperature side electrode 103, the electrode fixing bolt 108 is inserted into the through hole 102 g of the low temperature side electrode 102 and screwed to the connecting spacer 107. Further, an electrode fixing bolt 109 is inserted into a through hole (not shown) of the room temperature side electrode 103 and is screwed to the connecting spacer 107. At this time, solder having a predetermined thickness is disposed between the low temperature side electrode 102 and the Peltier element 101 and between the normal temperature side electrode 103 and the Peltier element 101.

電極固定ボルト１０９と常温側電極１０３のフランジ部１０３ｂとの間には、圧縮ばね１１０及び圧縮ばね押さえ金具１１１が介在する。これにより、電極固定ボルト１０９を締め付けたときに、圧縮ばね押さえ金具１１１とフランジ部１０３ｂとの間で圧縮ばね１０９が圧縮され、付勢力が生じる。この付勢力により、接合部Ｊに適切な圧力が付与される。すなわち、圧縮ばね１１０及び圧縮ばね押さえ金具１１１により圧力調整機構が構成され、固定ボルト１０９の連結スペーサー１０７への締め込み量を調整することにより、接合部Ｊに加わる圧力を適宜に調整することができる。 Between the electrode fixing bolt 109 and the flange portion 103 b of the room temperature side electrode 103, a compression spring 110 and a compression spring holding metal fitting 111 are interposed. Thereby, when the electrode fixing bolt 109 is tightened, the compression spring 109 is compressed between the compression spring pressing metal 111 and the flange portion 103b, and an urging force is generated. Due to this urging force, an appropriate pressure is applied to the joint J. In other words, the compression spring 110 and the compression spring pressing metal 111 constitute a pressure adjustment mechanism, and the pressure applied to the joint J can be appropriately adjusted by adjusting the amount of fastening of the fixing bolt 109 to the connection spacer 107. it can.

低温側電極１０２と常温側電極１０３との間にペルチェ素子１０１が挟持された状態で半田接合が行われる。具体的には、ペルチェ素子１０１と低温側電極１０２との接合は、突出枠部１０２ｄが上方を向くように配置し、低温側電極１０２に通電して半田の溶融温度（約２５０℃）まで加熱することにより行われる。同様に、ペルチェ素子１０１と常温側電極１０３との接合は、突出枠部１０３ｄが上方を向くように配置し、常温側電極１０３に通電して半田の溶融温度（約２５０℃）まで加熱することにより行われる。 Solder bonding is performed in a state where the Peltier element 101 is sandwiched between the low temperature side electrode 102 and the normal temperature side electrode 103. Specifically, the Peltier element 101 and the low temperature side electrode 102 are joined so that the protruding frame portion 102d faces upward, and the low temperature side electrode 102 is energized and heated to the melting temperature of the solder (about 250 ° C.). Is done. Similarly, the Peltier element 101 and the room temperature side electrode 103 are joined such that the protruding frame portion 103d faces upward, and the room temperature side electrode 103 is energized and heated to the melting temperature of the solder (about 250 ° C.). Is done.

溶融に伴い半田は接合面から押し出されるが、突出枠部１０２ｄで堰止められるので、接合面（半田層）に凹凸やボイド（微小な空隙）等の欠陥は生じない。したがって、これらの欠陥に起因して、熱伝導性が低下したり、電気抵抗が増大したりするのを防止できる。 Solder is pushed out from the joint surface as it melts, but is dammed by the protruding frame portion 102d, so that defects such as irregularities and voids (minute voids) do not occur on the joint surface (solder layer). Therefore, it is possible to prevent the thermal conductivity from decreasing or the electrical resistance from increasing due to these defects.

低温側補助電極１０５は、低温側電極１０２と軸方向にほぼ対称な構造を有する。すなわち、低温側補助電極１０５は、リード固定部１０５ａ、リード固定部１０５ａよりも大径のフランジ部１０５ｂ、及びかしめ部１０５ｃを有する。リード固定部１０５ａに銅リード１５が接続される。フランジ部１０５ｂは、径方向に形成されるボルト固定穴を有し、このボルト固定穴に補強筒固定ボルト１１２が螺合される。かしめ部１０５ｃは、軸方向に形成された導体挿入口（図示略）を有する。この導体挿入口にフレキシブル導体１０６の他端が挿入された状態で平面加圧される。かしめ部１０５ｃが塑性変形することにより、低温側補助電極１０５とフレキシブル導体１０６とがかしめにより接続される。かしめ部１０５ｃの構造は、低温側電極１０２のかしめ部１０２ｃと同様であるので説明を省略する。 The low temperature side auxiliary electrode 105 has a substantially symmetrical structure with the low temperature side electrode 102 in the axial direction. That is, the low temperature side auxiliary electrode 105 includes a lead fixing portion 105a, a flange portion 105b having a larger diameter than the lead fixing portion 105a, and a caulking portion 105c. The copper lead 15 is connected to the lead fixing portion 105a. The flange portion 105b has a bolt fixing hole formed in the radial direction, and the reinforcing cylinder fixing bolt 112 is screwed into the bolt fixing hole. The caulking portion 105c has a conductor insertion opening (not shown) formed in the axial direction. Flat pressure is applied in a state where the other end of the flexible conductor 106 is inserted into the conductor insertion port. As the caulking portion 105c is plastically deformed, the low temperature side auxiliary electrode 105 and the flexible conductor 106 are connected by caulking. The structure of the caulking portion 105 c is the same as that of the caulking portion 102 c of the low temperature side electrode 102, and thus description thereof is omitted.

フレキシブル導体１０６は、例えば平編み銅線で構成される。フレキシブル導体１０４は、電流リード１０に生じる曲げや歪み、特にペルチェ素子１０１、低温側電極１０２、常温側電極１０３の接合部Ｊに生じる曲げや歪みを吸収する。 The flexible conductor 106 is made of, for example, a flat knitted copper wire. The flexible conductor 104 absorbs bending and distortion generated in the current lead 10, particularly bending and distortion generated in the joint J of the Peltier element 101, the low temperature side electrode 102, and the normal temperature side electrode 103.

補強筒１０４は、電流リード１０の設置時などに意図しない外力が働いたときに、この外力を直接受ける補強部材であり、少なくともペルチェ素子１０１と、低温側電極１０２及び常温側電極１０３ａとの接合部Ｊの周囲を取り囲むように配置される。補強筒１０４は、補強筒固定ボルト１１２、１１３により、低温側補助電極１０５及び常温側電極１０３に固定される。 The reinforcing cylinder 104 is a reinforcing member that directly receives an external force when an unintended external force is applied, for example, when the current lead 10 is installed. At least the Peltier element 101 is joined to the low temperature side electrode 102 and the normal temperature side electrode 103a. It arrange | positions so that the circumference | surroundings of the part J may be surrounded. The reinforcing cylinder 104 is fixed to the low temperature side auxiliary electrode 105 and the normal temperature side electrode 103 by reinforcing cylinder fixing bolts 112 and 113.

補強筒１０４には、ＧＦＲＰ製のものが好適である。ＧＦＲＰ製の補強筒１０４を用いることにより、外部からの熱の流入を遮断することができるので、補強筒１０４で覆われた内部の素子ユニットの温度上昇、及びこれに伴う機器の損傷、劣化を防止することができる。 The reinforcing cylinder 104 is preferably made of GFRP. By using the reinforcing tube 104 made of GFRP, it is possible to block the inflow of heat from the outside, so that the temperature rise of the internal element unit covered with the reinforcing tube 104 and the damage and deterioration of the equipment accompanying this increase. Can be prevented.

補強筒１０４は、周面の一部に切欠窓１０４ａを有する。切欠窓１０４ａの数、形状、大きさ、及び位置は特に制限されない。補強筒１０４に切欠窓１０４ａを設けることにより、補強筒１０４を用いない場合と同様に、効率よく真空排気を行うことができる。 The reinforcing cylinder 104 has a cutout window 104a in a part of its peripheral surface. The number, shape, size, and position of the cutout window 104a are not particularly limited. By providing the cutout window 104a in the reinforcing cylinder 104, it is possible to perform evacuation efficiently as in the case where the reinforcing cylinder 104 is not used.

切欠窓１０４ａは、外部から接合部Ｊの全部を観察できるように、形状、大きさ、及び位置が設定されるのが好ましい。外部から接合部Ｊを観察する観点から、切欠窓１０４ａは、機械的な強度が確保される範囲で、大きい方が好ましい。切欠窓１０４ａの寸法は、補強筒１０４の材料と厚みを考慮して適宜に設定される。 The cutout window 104a is preferably set in shape, size, and position so that the entire joint J can be observed from the outside. From the viewpoint of observing the joint portion J from the outside, it is preferable that the cutout window 104a is larger as long as mechanical strength is ensured. The dimensions of the cutout window 104a are appropriately set in consideration of the material and thickness of the reinforcing cylinder 104.

ここでは、切欠窓１０４ａは、例えば軸方向の長さが接合部Ｊの軸方向の長さ以上である矩形窓である。また、切欠窓１０４ａは、周方向に沿って等間隔で設けられる。この場合、形成間隔（図４Ｂの角度φに相当）は中心角で９０°未満であることが好ましい。これにより、外部から接合部Ｊの全部を容易に観察することができる。 Here, the cutout window 104a is, for example, a rectangular window whose axial length is equal to or greater than the axial length of the joint J. The cutout windows 104a are provided at equal intervals along the circumferential direction. In this case, the formation interval (corresponding to the angle φ in FIG. 4B) is preferably less than 90 ° in the central angle. Thereby, the whole junction part J can be easily observed from the outside.

このように、電流リード１０は、超電導コイル１１（超電導応用機器）に接続される低温側電極１０２と、電源１２（外部機器）に接続される常温側電極１０３と、一方の面に低温側電極１０２が接合され、他方の面に常温側電極１０３が接合されるペルチェ素子１０１（熱電変換素子）と、ペルチェ素子１０１、低温側電極１０２、及び常温側電極１０３を含む素子ユニットに固定され、ペルチェ素子１０１と低温側電極１０２との低温側接合部、及びペルチェ素子１０１と常温側電極１０３との常温側接合部を含む接合部Ｊの周囲を取り囲む補強筒１０４と、を備える。補強筒１０４は、周面の一部に、切欠窓１０４ａを有する。 As described above, the current lead 10 includes the low temperature side electrode 102 connected to the superconducting coil 11 (superconducting application device), the normal temperature side electrode 103 connected to the power source 12 (external device), and the low temperature side electrode on one surface. Is fixed to an element unit including a Peltier element 101 (thermoelectric conversion element) in which a room temperature side electrode 103 is bonded to the other surface, a Peltier element 101, a low temperature side electrode 102, and a room temperature side electrode 103. And a reinforcing cylinder 104 surrounding the periphery of the junction J including the low temperature side junction between the element 101 and the low temperature side electrode 102 and the normal temperature side junction between the Peltier element 101 and the normal temperature side electrode 103. The reinforcing cylinder 104 has a cutout window 104a in a part of its peripheral surface.

電流リード１０によれば、補強筒１０４を設けることに伴い作業効率が低下するのを防止できるとともに、接合部Ｊの外観観察を容易に行うことができる。したがって、電流リード１０は、安定した特性を有する信頼性の高いものとなる。 According to the current lead 10, it is possible to prevent the work efficiency from being lowered due to the provision of the reinforcing cylinder 104, and it is possible to easily observe the appearance of the joint portion J. Therefore, the current lead 10 has a stable characteristic and high reliability.

[実施例１]
実施例１では、図２に示す電流リード１０において、補強筒１０４の周面に、接合部Ｊから低温側補助電極１０５のかしめ部１０５ｃにわたって切欠窓１０４ａを形成した。切欠窓１０４ａの軸方向の長さは２５ｍｍ、幅は中心角で６０°、形成間隔は中心角で３０°とした。 [Example 1]
In Example 1, in the current lead 10 shown in FIG. 2, a notch window 104 a was formed on the peripheral surface of the reinforcing cylinder 104 from the joint J to the caulking part 105 c of the low temperature side auxiliary electrode 105. The cutout window 104a has an axial length of 25 mm, a width of 60 ° in the central angle, and a formation interval of 30 ° in the central angle.

[実施例２]
実施例２では、図２に示す電流リード１０において、補強筒１０４の周面に、接合部Ｊに対応する位置に切欠部１０４ａを形成した。切欠部１０４ａの軸方向の長さは８ｍｍ、幅及び形成間隔は実施例１と同様とした。 [Example 2]
In the second embodiment, in the current lead 10 shown in FIG. The length of the notch 104a in the axial direction was 8 mm, and the width and formation interval were the same as in Example 1.

［比較例］
比較例では、図２に示す電流リード１０において、切欠窓１０４ａのない補強筒１０４を採用した。 [Comparative example]
In the comparative example, in the current lead 10 shown in FIG.

実施例１、実施例２、及び比較例の電流リード１０を、それぞれ固定フランジ２０１に３７本固定した電流リード付きフランジユニットを端末容器１４（真空容器）に取り付け、真空ポンプで排気した。目標とする真空度を１．０×１０^−２Ｐａとした。同様の実験を３回繰り返し、真空排気時間を評価した。また、３７本の電流リード１０のうち、１０本の接合部Ｊの外観観察を行い、所要時間を計測した。評価結果を表１に示す。 A flange unit with current leads in which 37 current leads 10 of Example 1, Example 2, and Comparative Example were each fixed to a fixed flange 201 was attached to the terminal container 14 (vacuum container), and evacuated with a vacuum pump. The target degree of vacuum was set to 1.0 × 10 ⁻² Pa. The same experiment was repeated three times, and the evacuation time was evaluated. Further, out of the 37 current leads 10, the appearance of 10 joints J was observed, and the required time was measured. The evaluation results are shown in Table 1.

表１に示すように、実施例１、２では、補強筒１０４に切欠窓１０４ａを設けているので、比較例よりも排気時間を大幅に短縮することができた。 As shown in Table 1, in Examples 1 and 2, since the reinforcing cylinder 104 is provided with the notch window 104a, the exhaust time can be significantly shortened compared to the comparative example.

比較例は、補強筒１０４を固定するための補強筒固定ボルト１１２、１１３を取り外す作業や、補強筒１０４を慎重に抜き取る作業、接合部Ｊを観察した後に再度補強筒１０４を取り付ける作業が必要となるため、外観観察に１０分程度の時間がかかった。また、比較例では、１０本の電流リード１０のうち２本の電気抵抗が１０％以上増大した。外観観察作業により接合部Ｊに応力が加わったためと考えられる。 The comparative example requires an operation of removing the reinforcing cylinder fixing bolts 112 and 113 for fixing the reinforcing cylinder 104, an operation of carefully removing the reinforcing cylinder 104, and an operation of attaching the reinforcing cylinder 104 again after observing the joint portion J. Therefore, it took about 10 minutes to observe the appearance. In the comparative example, the electrical resistance of two of the ten current leads 10 increased by 10% or more. This is probably because stress was applied to the joint J by the appearance observation work.

これに対して、実施例１、２では、補強筒１０４を解体することなく接合部Ｊを視認できるため、１分以内と極めて容易に外観観察を行うことができた。また、実施例１、２では、外観観察後に電流リード１０の性能低下は見られなかった。実施例１は実施例２よりも切欠窓１０４ａが大きいため、より簡単に外観観察を行うことができた。 On the other hand, in Examples 1 and 2, since the joint portion J can be visually recognized without dismantling the reinforcing cylinder 104, it was possible to observe the appearance very easily within 1 minute. Further, in Examples 1 and 2, a decrease in performance of the current lead 10 was not observed after appearance observation. Since the cutout window 104a is larger in the first embodiment than in the second embodiment, the appearance can be observed more easily.

以上、本発明者によってなされた発明を実施の形態に基づいて具体的に説明したが、本発明は上記実施の形態に限定されるものではなく、その要旨を逸脱しない範囲で変更可能である。 As mentioned above, the invention made by the present inventor has been specifically described based on the embodiment. However, the present invention is not limited to the above embodiment, and can be changed without departing from the gist thereof.

低温側電極１０２及び常温側電極１０３の構造、並びに素子ユニットを補強筒１０４に固定する構造は、実施の形態で説明したものに限定されず、例えば特許文献３に記載の構造を適用することもできる。すなわち、低温側電極１０２を、熱電変換素子１０１に接合される低温側コア電極と、一端側が超電導応用機器に接続され他端側がプラグ・ソケット構造により低温側コア電極に接続される低温側キャップ電極と、を有する構成とし、常温側電極１０３を、熱電変換素子１０１に接合される常温側コア電極と、一端側が前記外部機器に接続され他端側がプラグ・ソケット構造により常温側コア電極に接続される常温側キャップ電極と、を有する構成としてもよい。この場合、低温側コア電極と低温側キャップ電極との間、及び常温側コア電極と常温側キャップ電極との間に多点接触式の接触子を介在し、固定部材により低温側キャップ電極と常温側キャップ電極とを連結する。素子ユニットは、熱電変換素子、低温側コア電極、及び常温側コア電極を含んで構成され、軸方向端部側に隙間がある状態で低温側キャップ電極と常温側キャップ電極とに挟持され、軸方向に移動可能な状態で維持される。 The structure of the low temperature side electrode 102 and the room temperature side electrode 103 and the structure for fixing the element unit to the reinforcing cylinder 104 are not limited to those described in the embodiment, and for example, the structure described in Patent Document 3 may be applied. it can. That is, the low temperature side electrode 102 is joined to the thermoelectric conversion element 101, the low temperature side core electrode is connected to the superconducting application device, and the other end side is connected to the low temperature side core electrode by the plug and socket structure. The room temperature side electrode 103 is joined to the thermoelectric conversion element 101, and one end side is connected to the external device, and the other end side is connected to the room temperature side core electrode by a plug and socket structure. And a room temperature side cap electrode. In this case, a multipoint contact is interposed between the low temperature side core electrode and the low temperature side cap electrode and between the normal temperature side core electrode and the normal temperature side cap electrode, and the low temperature side cap electrode and the normal temperature are fixed by a fixing member. Connect the side cap electrode. The element unit includes a thermoelectric conversion element, a low temperature side core electrode, and a normal temperature side core electrode, and is sandwiched between the low temperature side cap electrode and the normal temperature side cap electrode in a state where there is a gap on the axial end side. It is kept movable in the direction.

今回開示された実施の形態はすべての点で例示であって制限的なものではないと考えられるべきである。本発明の範囲は上記した説明ではなくて特許請求の範囲によって示され、特許請求の範囲と均等の意味および範囲内でのすべての変更が含まれることが意図される。 The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

１超電導磁石装置
１０電流リード
１１超電導コイル
１２電源
１３低温容器
１４端末容器
１５、１６銅リード
１０１ペルチェ素子
１０２低温側電極
１０２ｃかしめ部
１０２ｄ突出枠部
１０３常温側電極
１０３ｄ突出枠部
１０４補強筒
１０４ａ切欠窓
１０５低温側補助電極
１０５ｃかしめ部
１０６フレキシブル導体
２０電流リード固定用フランジユニット
２０１固定フランジ
２０２輻射熱防止板
２０２Ａ常温側バッフル板
２０２Ｂ低温側バッフル板
２０３シャフト
２０３Ａ常温側バッフル板用シャフト
２０３Ｂ低温側バッフル板用シャフト DESCRIPTION OF SYMBOLS 1 Superconducting magnet apparatus 10 Current lead 11 Superconducting coil 12 Power supply 13 Low temperature container 14 Terminal container 15, 16 Copper lead 101 Peltier element 102 Low temperature side electrode 102c Caulking part 102d Protruding frame part 103 Room temperature side electrode 103d Protruding frame part 104 Reinforcing cylinder 104a Notch Window 105 Low temperature side auxiliary electrode 105c Caulking portion 106 Flexible conductor 20 Current lead fixing flange unit 201 Fixed flange 202 Radiation heat prevention plate 202A Room temperature side baffle plate 202B Low temperature side baffle plate 203 Shaft 203A Room temperature side baffle plate shaft 203B Low temperature side baffle plate Shaft

Claims

A current lead for connecting a superconducting application device installed in a low temperature part and an external device installed in a normal temperature part,
A low temperature side electrode connected to the superconducting application device;
A room temperature side electrode connected to the external device;
A thermoelectric conversion element in which the low temperature side electrode is bonded to one surface and the room temperature side electrode is bonded to the other surface;
Fixed to an element unit including the thermoelectric conversion element, the low temperature side electrode, and the room temperature side electrode, a low temperature side junction between the thermoelectric conversion element and the low temperature side electrode, and the thermoelectric conversion element and the room temperature side electrode. A reinforcing cylinder surrounding the periphery of the joint including the room temperature side joint of
The reinforcing lead has a notch window in a part of its peripheral surface.

2. The current lead according to claim 1, wherein the cutout window has a shape, a size, and a position so that the whole of the joint portion can be observed from the outside.

3. The current lead according to claim 2, wherein the cutout window has an axial length equal to or greater than an axial length of the joint portion and is formed at a height equivalent to the joint portion.

The current lead according to claim 3, wherein the reinforcing cylinder has a plurality of the cutout windows provided in a circumferential direction.

5. The current lead according to claim 4, wherein the interval between the plurality of cutout windows is less than 90 ° in central angle.

The current lead according to any one of claims 1 to 5, further comprising a pressure adjusting mechanism capable of adjusting a pressure applied to the joint portion.

The low temperature side electrode is bonded to the thermoelectric conversion element, the low temperature side core electrode is connected to the superconducting application device, and the other end is connected to the low temperature side core electrode by a plug and socket structure. And having
The room temperature side core electrode joined to the thermoelectric conversion element, the room temperature side electrode connected to the external device, and the other end side connected to the room temperature side core electrode by a plug and socket structure, Have
A multipoint contact type contact between the low temperature side core electrode and the low temperature side cap electrode, and between the normal temperature side core electrode and the normal temperature side cap electrode,
A fixing member for connecting the low temperature side cap electrode and the normal temperature side cap electrode,
The element unit is configured to include the thermoelectric conversion element, the low temperature side core electrode, and the normal temperature side core electrode, and the low temperature side cap electrode and the normal temperature side cap electrode in a state where there is a gap on the axial end side. 6. The current lead according to claim 1, wherein the current lead is maintained in a state of being movable in the axial direction.