JPH07320928A - Superconducting magnet - Google Patents
Superconducting magnetInfo
- Publication number
- JPH07320928A JPH07320928A JP11324194A JP11324194A JPH07320928A JP H07320928 A JPH07320928 A JP H07320928A JP 11324194 A JP11324194 A JP 11324194A JP 11324194 A JP11324194 A JP 11324194A JP H07320928 A JPH07320928 A JP H07320928A
- Authority
- JP
- Japan
- Prior art keywords
- magnet
- conductor
- superconducting
- stress
- coil
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
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- Containers, Films, And Cooling For Superconductive Devices (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は磁気共鳴画像診断装置
（ＭＲＩ）等に使用されるソレノイド状に巻回した超伝
導磁石に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solenoidally wound superconducting magnet used in a magnetic resonance imaging system (MRI) or the like.
【０００２】[0002]
【従来の技術】超伝導磁石は、無損失で高磁界を安定的
に維持できるため核磁気共鳴を利用した医療用画像診断
装置（ＭＲＩ）を始めとして、超伝導エネルギー貯蔵装
置（ＳＭＥＳ）や超伝導発電機等に応用が広がってきて
いる。2. Description of the Related Art Since a superconducting magnet can maintain a high magnetic field stably without loss, it can be used in medical image diagnostic equipment (MRI) utilizing nuclear magnetic resonance, superconducting energy storage equipment (SMES) and Applications are spreading to conduction generators.
【０００３】超伝導磁石の性能の上限は、超伝導現象が
破れ常電導状態に転移するいわゆるクエンチ現象により
規定されるが、磁石のクエンチ点は種々の擾乱により、
コイルに使用されている超伝導導体のクエンチ電流（臨
界電流）に到達しない場合が多い。The upper limit of the performance of a superconducting magnet is defined by the so-called quench phenomenon in which the superconducting phenomenon breaks and the superconducting phenomenon is transferred to the normal conducting state.
In many cases, the quench current (critical current) of the superconducting conductor used for the coil is not reached.
【０００４】これら擾乱には、導体接続部の発熱や、交
流損失やフラックスジャンプの様に導体に起因する擾乱
や、導体が動くことによる機械的擾乱がある。接続部の
発熱は設計手法により、また導体に起因するものは導体
開発が進むにつれて解決されており、現在、高性能超伝
導マグネットの性能を制限する最大の原因は機械的擾乱
となっている。[0004] These disturbances include heat generation at the conductor connection portion, disturbances caused by the conductors such as AC loss and flux jump, and mechanical disturbances caused by movement of the conductors. The heat generation of the connection part has been solved by the design method, and the one caused by the conductor has been solved as the conductor development progressed, and at present, the mechanical disturbance is the biggest cause of limiting the performance of the high performance superconducting magnet.
【０００５】図５に従来の超伝導磁石の縦断面図を示
す。同図に示すように、超伝導磁石は、巻枠１に導体２
を巻き付けてコイル３とし、導体２が動くことによる機
械的擾乱を低減するためにエポキシ等の充填材４を用い
て導体同志を接着して導体の動きを抑制する手法が採ら
れている。FIG. 5 shows a vertical sectional view of a conventional superconducting magnet. As shown in the figure, the superconducting magnet includes a winding frame 1 and a conductor 2
Is used to form a coil 3, and in order to reduce mechanical disturbance caused by the movement of the conductor 2, a conductor 4 is bonded by using a filler 4 such as epoxy to suppress the movement of the conductor.
【０００６】[0006]
【発明が解決しようとする課題】このように、エポキシ
等の充填材４を用いて導体同志を接着して導体の動きを
抑制する手法を用いた磁石では、エポキシ等の充填材４
に亀裂が生じたりして特性が劣化したり、経年的に性能
が低下する問題点がある上、含浸剤を用いるため材料費
や製造過程が複雑になり高価となる問題があった。As described above, in the magnet using the technique of adhering the conductors to each other by using the filler 4 such as epoxy to suppress the movement of the conductor, the filler 4 such as epoxy is used.
There are problems that properties are deteriorated due to cracks in the product, performance deteriorates over time, and material costs and manufacturing processes are complicated and expensive due to the use of the impregnating agent.
【０００７】本発明は上記の課題を解決するためになさ
れたものであり、エポキシ等の充填材を用いずに導体の
動きによる機械的擾乱を発生せず、励磁途中で超伝導現
象が破れ常電導状態に転移するいわゆるクエンチ現象を
起こさずに、コイルに使用されている超伝導導体のクエ
ンチ電流（臨界電流）を達成し、経年的に性能が劣化せ
ずに安価に製造できるソレノイド状超伝導磁石を提供す
る事を目的とする。The present invention has been made in order to solve the above-mentioned problems. It does not generate mechanical disturbance due to the movement of the conductor without using a filler such as epoxy, and the superconducting phenomenon is always broken during excitation. Solenoid-like superconductivity that achieves the quench current (critical current) of the superconducting conductor used in the coil without causing the so-called quench phenomenon that transitions to the conductive state, and can be manufactured inexpensively without deterioration in performance over time. The purpose is to provide a magnet.
【０００８】[0008]
【課題を解決するための手段】本発明においては超伝導
磁石は、超伝導線材をソレノイド状に巻回し、エポキシ
等の充填材による固定法を用いず、熱収縮により発生す
る磁石内応力を巻線張力による応力で補償し、前記磁石
冷却後に磁石内応力が僅かに圧縮状態になるように巻線
張力を調整して構成する。In the present invention, a superconducting magnet has a structure in which a superconducting wire is wound in a solenoid shape and the stress in the magnet generated by thermal contraction is wound without using a fixing method with a filler such as epoxy. The coil tension is compensated by the stress due to the linear tension, and the winding tension is adjusted so that the stress in the magnet is slightly compressed after cooling the magnet.
【０００９】[0009]
【作用】上記のような手段を講ずることにより、所定の
運転電流を通電した際には磁石コイルが巻枠から浮き上
がり離型し、コイル内の径方向応力による超伝導導体に
径方向に作用する力と、電磁力等により軸方向に作用す
る力の比が、導線同志の静止摩擦係数より大きくなり、
励磁初期に軸方向の導体の動きが容易に発生する。By taking the above-mentioned means, when a predetermined operating current is applied, the magnet coil is lifted from the winding frame and released from the mold, and acts radially on the superconducting conductor due to the radial stress in the coil. The ratio of the force to the force acting in the axial direction due to electromagnetic force, etc., is greater than the static friction coefficient of the conductors,
The movement of the conductor in the axial direction easily occurs at the initial stage of excitation.
【００１０】これにより、巻枠１とコイル３は離型する
ために機械的に擦れて発熱する事がなく、機械的擾乱が
発生しない。また導体同志の動きは、上記の力の比が静
止摩擦係数より大きくなっているため、超伝導導体の臨
界温度に対する裕度の大きい励磁初期に発生する。この
ため励磁途中でクエンチ現象を発生せずに、コイルに使
用されている超伝導導体のクエンチ電流（臨界電流）を
達成する。また、経年的に性能が劣化せずに、製造費も
安価となる。As a result, since the reel 1 and the coil 3 are released from each other, they are not mechanically rubbed to generate heat and no mechanical disturbance occurs. Further, the movement of the conductors occurs in the initial stage of excitation, which has a large margin with respect to the critical temperature of the superconducting conductor, because the ratio of the forces is larger than the static friction coefficient. Therefore, the quenching current (critical current) of the superconducting conductor used in the coil is achieved without causing the quenching phenomenon during the excitation. Further, the performance is not deteriorated over time, and the manufacturing cost is low.
【００１１】[0011]
【実施例】以下本発明の実施例を、ホルマール被覆が施
されたＮｂＴｉ超伝導導体を用いて構成する場合の図面
を参照して説明する。図１は、本発明によるソレノイド
状超伝導磁石の縦断面を示す図である。Embodiments of the present invention will be described below with reference to the drawings in the case of using a NbTi superconducting conductor having a formal coating. FIG. 1 is a view showing a longitudinal section of a solenoidal superconducting magnet according to the present invention.
【００１２】同図に示すように超伝導磁石は、巻枠１に
ホルマール被覆を施した導体２を、図２に示す様に、熱
収縮により発生する磁石内応力を巻線張力による応力で
補償し、前記磁石冷却後に磁石内応力が僅かに圧縮状態
になるように巻線張力を調整して巻き付けてコイル３と
して構成する。In the superconducting magnet as shown in the figure, the conductor 2 having a formal coating on the winding frame 1 is used to compensate the stress in the magnet generated by thermal contraction by the stress due to the winding tension as shown in FIG. Then, the coil tension is adjusted so that the stress in the magnet is slightly compressed after cooling the magnet, and the coil 3 is wound to form the coil 3.
【００１３】このような構成による超伝導磁石を励磁す
ると、図３に示すように、コイル内の径方向応力による
超伝導導体に径方向に作用する力で、電磁力等により軸
方向に作用する力を除した比が、ホルマール被覆を施し
た導線同志の静止摩擦係数０．２６より大きくなり、励
磁初期に軸方向の導体の動きが容易に発生する。また、
図２に示したように励磁初期にコイル内径側の径方向応
力が零となり磁石コイルが巻枠から浮き上がり、所定の
運転電流を通電した際には磁石コイルが巻枠から離型す
る。When the superconducting magnet having such a structure is excited, as shown in FIG. 3, the force acting in the radial direction on the superconducting conductor due to the radial stress in the coil acts in the axial direction by the electromagnetic force or the like. The ratio obtained by dividing the force becomes larger than the static friction coefficient of 0.26 between the formal-coated conductors, and the movement of the conductor in the axial direction easily occurs at the initial stage of excitation. Also,
As shown in FIG. 2, the radial stress on the inner diameter side of the coil becomes zero in the initial stage of excitation, and the magnet coil floats up from the winding frame. When a predetermined operating current is applied, the magnet coil is released from the winding frame.
【００１４】これにより、巻枠１とコイル３は離型する
ために、機械的に擦れて発熱する事がなくなり、機械的
擾乱が発生しない。また導体同志の動きは、上記のよう
に、超伝導導体の臨界温度に対する裕度の大きい励磁初
期に発生するため励磁途中でクエンチ現象を発生せず
に、図４に示すようにコイルに使用されている超伝導導
体のクエンチ電流（臨界電流）を達成する。また、従来
のように導体の動きを抑制するためにエポキシ等の充填
材を用いないので、エポキシ等の充填材の亀裂の発生で
特性が劣化したり、経年的に性能が低下することがな
く、製造費も安価となる。As a result, the winding frame 1 and the coil 3 are released from each other, so that they are not mechanically rubbed to generate heat, and no mechanical disturbance occurs. As described above, the movement of the conductors occurs in the initial stage of the excitation, which has a large margin with respect to the critical temperature of the superconducting conductor, and therefore does not cause the quench phenomenon during the excitation and is used for the coil as shown in FIG. To achieve a quenching current (critical current) of a superconducting conductor that is in operation. In addition, since a filler such as epoxy is not used to suppress the movement of the conductor as in the conventional case, there is no deterioration in the characteristics due to the occurrence of cracks in the filler such as epoxy or deterioration in performance over time. Also, the manufacturing cost will be low.
【００１５】尚、本発明は以上のホルマル被覆のＮｂＴ
ｉ超伝導導体を用いた場合の実施例に限定されるもので
はなく、例えば酸化皮膜や、金属皮膜を用いたＮｂＴｉ
導体やＮｂ3 Ｓｎ導体、さらに円形断面を有する導体
等、その要旨を変更しない範囲で種々変形して実施でき
ることは勿論である。The present invention is based on the above formal-coated NbT.
The embodiment is not limited to the case of using a superconducting conductor, and for example, NbTi using an oxide film or a metal film is used.
It is needless to say that various modifications such as a conductor, an Nb 3 Sn conductor, and a conductor having a circular cross section can be implemented without changing the gist thereof.
【００１６】[0016]
【発明の効果】以上説明した様に本発明によれば、エポ
キシ等の充填材を用いずに導体の動きによる機械的擾乱
を発生せず、励磁途中で超伝導現象が破れ常電導状態に
転移するいわゆるクエンチ現象を起こさずに、コイルに
使用されている超伝導導体のクエンチ電流（臨界電流）
を達成し、経年的に性能が劣化せずに安価に製造できる
ソレノイド状超伝導磁石を提供する事ができる。As described above, according to the present invention, a mechanical disturbance due to the movement of the conductor is not generated without using a filler such as epoxy, the superconducting phenomenon is broken during the excitation, and the state is changed to the normal conducting state. Quench current (critical current) of the superconducting conductor used in the coil without causing the so-called quench phenomenon.
It is possible to provide a solenoid-shaped superconducting magnet that can be manufactured at low cost by achieving the above, without deteriorating the performance over time.
【図１】本発明による超伝導磁石の縦断面。FIG. 1 is a longitudinal section of a superconducting magnet according to the present invention.
【図２】本発明の一実施例のホルマール被覆を施した超
伝導導体を用いた際のコイル内の半径方向成分応力の半
径方向分布図。FIG. 2 is a radial distribution diagram of radial component stress in a coil when a formal-coated superconducting conductor according to an embodiment of the present invention is used.
【図３】実施例の磁石を励磁した際のコイル内径位置で
の磁界を横軸に取った、コイル内の径方向応力による超
伝導導体に径方向に作用する力で、電磁力等により軸方
向に作用する力を除した比。FIG. 3 is a force acting in a radial direction on a superconducting conductor due to a radial stress in the coil, in which the magnetic field at the inner diameter position of the coil when the magnet of the embodiment is excited is plotted on the horizontal axis. Ratio divided by the force acting in the direction.
【図４】実施例の磁石を励磁した際の励磁回数と、使用
したＮｂＴｉ超伝導導体の臨界電流に対する到達割合を
示したもの。FIG. 4 is a graph showing the number of times of excitation when the magnet of the example was excited and the reaching ratio of the used NbTi superconducting conductor to the critical current.
【図５】従来のエポキシ等の充填材を用いて導体の動き
による機械的擾乱を抑制した超伝導磁石の縦断面図。FIG. 5 is a vertical cross-sectional view of a superconducting magnet in which a mechanical disturbance due to movement of a conductor is suppressed by using a conventional filler such as epoxy.
１…コイル巻枠 ２…超伝導導体 ３…超伝導磁石 ４…エポキシ等充填材 1 ... Coil winding frame 2 ... Superconducting conductor 3 ... Superconducting magnet 4 ... Filling material such as epoxy
Claims (1)
浸剤による固定法を用いない超伝導磁石に於いて、熱収
縮による磁石内応力を巻線張力による応力で補償し、前
記磁石冷却後に磁石内応力が僅かに圧縮状態になるよう
にし、所定の運転電流を通電した際には磁石コイルが巻
枠から浮上し離型し、コイル内の径方向応力による超伝
導導体に径方向に作用する力で、電磁力等による軸方向
に作用する力を除した比が、使用冷媒温度での導線同志
の静止摩擦係数より大きく、励磁初期に軸方向の導体の
動きが容易に発生するよう巻線張力の調整を行うことを
特徴とする超伝導磁石。1. In a superconducting magnet in which a superconducting wire is wound in a solenoid shape and a fixing method using an impregnating agent is not used, stress in the magnet due to thermal contraction is compensated by stress due to winding tension, and after cooling the magnet. The stress inside the magnet is slightly compressed, and when a predetermined operating current is applied, the magnet coil floats from the bobbin and separates from it, acting on the superconducting conductor in the radial direction due to the radial stress in the coil. The ratio obtained by dividing the force acting in the axial direction due to the electromagnetic force, etc. is larger than the coefficient of static friction between the conductors at the temperature of the refrigerant used, so that the conductor can easily move in the axial direction at the initial stage of excitation. A superconducting magnet characterized by adjusting the linear tension.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11324194A JPH07320928A (en) | 1994-05-27 | 1994-05-27 | Superconducting magnet |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11324194A JPH07320928A (en) | 1994-05-27 | 1994-05-27 | Superconducting magnet |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH07320928A true JPH07320928A (en) | 1995-12-08 |
Family
ID=14607151
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP11324194A Pending JPH07320928A (en) | 1994-05-27 | 1994-05-27 | Superconducting magnet |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH07320928A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100443702B1 (en) * | 2002-05-18 | 2004-08-09 | 한국표준과학연구원 | Apparatus for stabilizing magnetic field |
| JP2008140905A (en) * | 2006-11-30 | 2008-06-19 | Sumitomo Electric Ind Ltd | Superconductive coil |
-
1994
- 1994-05-27 JP JP11324194A patent/JPH07320928A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100443702B1 (en) * | 2002-05-18 | 2004-08-09 | 한국표준과학연구원 | Apparatus for stabilizing magnetic field |
| JP2008140905A (en) * | 2006-11-30 | 2008-06-19 | Sumitomo Electric Ind Ltd | Superconductive coil |
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