JP5810647B2 - High temperature superconducting coil and laminated high temperature superconducting coil - Google Patents

Description

  The present invention relates to a high temperature superconducting coil and a laminated high temperature superconducting coil.

  As oxide superconducting wires such as bismuth (Bi) or yttrium (Y), superconducting wires having a band-like surface are widely used. The influence of the magnetic field on the characteristics of such a superconducting wire has anisotropy. Specifically, it is known that in this superconducting wire, when the magnetic field perpendicular to the belt-like surface (vertical magnetic field) becomes high, performance degradation such as reduction in critical current and increase in AC loss occurs. As a technique for suppressing this performance degradation, for example, there is a technique related to a superconducting coil disclosed in Japanese Patent Application Laid-Open No. 2008-244280.

  According to this publication, the winding of the superconducting wire is changed between the central side and both ends in the axial direction of the superconducting coil. The wide surface of the superconducting wire on the center side in the axial direction is aligned with the axis of the coil, and the wide surface of the superconducting wire on the inner peripheral side is inclined with respect to the axis of the coil at both ends in the axial direction. The surface is orthogonal to the coil axis. More specifically, in the coil portion where the winding direction of the superconducting wire is changed, the inclination angle of the wide surface of the superconducting wire with respect to the axis of the winding frame is gradually increased for each turn from the inner peripheral side to the outer peripheral side. .

JP 2008-244280 A

  According to the technique of the above publication, the superconducting wire needs to be wound on the outer peripheral side of the superconducting coil while the wide surface (strip-shaped surface) of the superconducting wire is largely inclined with respect to the coil axis (winding shaft). . In particular, at both ends and the outer peripheral side of the superconducting coil, the superconducting wire needs to be wound around the winding axis while the strip surface of the superconducting wire is substantially perpendicular to the winding axis. In this case, a large stress is applied to the superconducting wire in the in-plane direction of the belt-like surface. Such stress causes large distortion of the oxide superconducting wire. When such a large strain exceeds the allowable value and is applied to the oxide superconducting wire, a significant deterioration in electrical characteristics occurs, for example, a deterioration in critical current characteristics of the superconducting coil.

  Therefore, the object of the present invention can suppress at least one of a decrease in critical current and an increase in AC loss due to a vertical magnetic field while avoiding remarkable deterioration of electrical characteristics due to distortion of the superconducting wire. It is to provide a high temperature superconducting coil and a laminated high temperature superconducting coil.

  The high-temperature superconducting coil of the present invention is formed by winding an oxide superconducting wire having a band-like surface around a virtual winding axis, and includes a pair of straight portions and a pair of curved portions. Have The pair of linear portions are opposed to each other with the winding shaft therebetween, and extend in parallel to each other. In at least a part of the pair of straight portions, the belt-like surface is inclined with respect to the winding axis. The pair of curved portions together with the pair of straight portions form a race track shape. The maximum value of the angle between the band surface and the winding axis in the pair of curved portions is smaller than the maximum value of the angle between the band surface and the winding axis in the pair of straight portions.

  According to the high temperature superconducting coil of the present invention, the belt-like surface of the superconducting wire has a portion inclined with respect to the winding axis. Thereby, unlike the case where all of the belt-like surfaces are parallel to the winding axis, the direction of the belt-like surface can be adjusted so that the vertical magnetic field received by the superconducting wire from the magnetic field inclined with respect to the winding shaft is reduced. Therefore, at least one of a decrease in critical current and an increase in AC loss can be suppressed.

  Further, the maximum value of the angle of the belt-shaped surface with respect to the winding axis is made smaller in the curved portion than in the straight portion. As a result, the stress of the superconducting wire is reduced as compared with the case where the belt-like surface is inclined at the curved portion to the same extent as the straight portion. Therefore, since the distortion of the superconducting wire due to the stress is reduced, the remarkable deterioration of the electrical characteristics of the superconducting wire can be avoided more reliably.

  As described above, the high-temperature superconducting coil of the present invention suppresses at least one of the decrease in the critical current and the increase in the AC loss due to the vertical magnetic field while avoiding the remarkable deterioration of the electrical characteristics due to the distortion of the superconducting wire. can do.

  Preferably, in the above high-temperature superconducting coil, the strip surface and the winding axis are parallel to each other in the pair of curved portions. Thereby, the stress of a superconducting wire can be made smaller. Therefore, the remarkable deterioration of the electrical characteristics due to the distortion of the superconducting wire can be avoided more sufficiently.

  Preferably, the high-temperature superconducting coil has an outer dimension smaller than a dimension obtained by adding half the width dimension to the width dimension of the belt-shaped surface in the direction of the winding axis. Thereby, the shape of the superconducting coil can be made flat within an error range that is half the width of the belt-like surface.

  Preferably, in at least a part of the pair of straight portions, the belt-like surface on the outer peripheral side has a larger inclination with respect to the winding axis than the belt-like surface on the inner peripheral side. Thereby, the inclination of the strip | belt-shaped surface of a superconducting wire can be changed so that it may respond | correspond to the magnetic field distribution which the direction inclines with respect to a winding axis, so that it leaves | separates from a winding axis. Therefore, the vertical magnetic field received by the superconducting wire can be reduced in a wider area. Therefore, at least one of a decrease in critical current and an increase in AC loss can be further suppressed.

  The laminated high-temperature superconducting coil of the present invention is formed by laminating a plurality of high-temperature superconducting coils, and has a first high-temperature superconducting coil and a second high-temperature superconducting coil. The first high-temperature superconducting coil is formed by winding an oxide superconducting wire having a first band-like surface around a virtual winding axis. The first high-temperature superconducting coil has a pair of straight portions that face each other across the winding axis and extend in parallel to each other. In at least a part of the pair of straight portions, the first belt-like surface is inclined with respect to the winding axis. The first high-temperature superconducting coil has a pair of curved portions that form a racetrack shape together with a pair of straight portions. The maximum value of the angle between the first belt surface and the winding axis in the pair of curved portions is smaller than the maximum value of the angle between the first belt surface and the winding shaft in the pair of straight portions. The second high-temperature superconducting coil is formed by winding an oxide superconducting wire having a second band-shaped surface around a winding axis. In the second high-temperature superconducting coil, the second strip surface and the winding axis are parallel to each other.

  According to the multilayer high-temperature superconducting coil of the present invention, the first high-temperature superconducting coil is disposed in a magnetic field region having a large inclination with respect to the winding axis under a magnetic field distribution in which the inclination with respect to the winding axis is not constant in the stacking direction. By disposing the second high-temperature superconducting coil in the magnetic field region where the inclination with respect to is small, the vertical magnetic field received by the superconducting wire can be reduced in a wider region. Therefore, at least one of a decrease in critical current and an increase in AC loss can be further suppressed. In addition, since the belt-like surface of the second high-temperature superconducting coil is parallel to the winding axis, the superconducting wire winding work for manufacturing the second high-temperature superconducting coil can be easily performed.

  As described above, according to the high-temperature superconducting coil of the present invention, at least one of the decrease in the critical current and the increase in the AC loss due to the vertical magnetic field while avoiding the remarkable deterioration of the electrical characteristics due to the distortion of the superconducting wire. Can be suppressed.

It is a perspective view which shows schematically the structure of the laminated high temperature superconducting coil in Embodiment 1 of this invention. It is a perspective view which shows roughly one structure of the several high temperature superconducting coil which the laminated | stacked high temperature superconducting coil of FIG. 1 has. It is a perspective view which shows roughly one structure of the several high temperature superconducting coil which the laminated | stacked high temperature superconducting coil of FIG. 1 has. It is a cross-sectional perspective view which shows roughly an example of a structure of the oxide superconducting wire used for the laminated | stacked high temperature superconducting coil of FIG. FIG. 2 is a schematic plan view of the laminated high temperature superconducting coil of FIG. 1. It is a schematic sectional drawing in alignment with line VI-VI of FIG. FIG. 6 is a schematic cross-sectional view taken along line VII-VII in FIG. 5. It is sectional drawing corresponding to the visual field of FIG. 6 of the laminated | stacked high temperature superconducting coil of a 1st comparative example. It is a figure which shows an example of the simulation result of the magnetic field distribution in xy plane of FIG. It is a graph which shows an example of the average perpendicular magnetic field added to each high temperature superconducting coil in each of a 1st comparative example and Embodiment 1 of this invention. It is a graph which shows an example of the alternating current loss which arises in each high temperature superconducting coil in each of a 1st comparative example and Embodiment 1 of this invention. It is a schematic top view of the high temperature superconducting coil of the 2nd comparative example. It is a schematic sectional drawing in alignment with line XIII-XIII of FIG. It is a schematic diagram which shows the part in which the stress added to an oxide superconducting wire in the high temperature superconducting coil of FIG. 12 is calculated. It is sectional drawing corresponding to the visual field of FIG. 6 which shows the structure of the multilayer high temperature superconducting coil in Embodiment 2 of this invention roughly.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following drawings, the same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated.

(Embodiment 1)
Referring to FIG. 1, laminated high temperature superconducting coil 90 of the present embodiment is formed by laminating high temperature superconducting coils 80a to 80h. Each of the high-temperature superconducting coils 80a to 80h is formed by winding the high-temperature superconducting wire 10 around a virtual winding axis AX. The number of turns is, for example, about 25 turns.

  Further, referring to FIGS. 2 and 3, in the present embodiment, a pair of high temperature superconducting coils 80a and 80b constitute a so-called double pancake coil. That is, the high temperature superconducting coils 80a and 80b are wound in opposite directions. Further, the inner peripheral side ends TI of the high-temperature superconducting wires 10 of the high-temperature superconducting coils 80a and 80b are electrically connected to each other. A pair of high temperature superconducting coils 80c and 80d, a pair of high temperature superconducting coils 80e and 80f, and a pair of high temperature superconducting coils 80g and 80h also constitute a double pancake coil. Adjacent double pancakes are connected in series using the outer peripheral end TE of the high-temperature superconducting wire 10. Therefore, the inductance of the laminated high temperature superconducting coil 90 is the sum of the inductances of the high temperature superconducting coils 80a to 80h.

  Referring to FIG. 4, high-temperature superconducting wire 10 extends over an arbitrary length with a width dimension W and a thickness dimension T. The width dimension W is larger than the thickness dimension T. Therefore, high-temperature superconducting wire 10 includes a strip-shaped surface SP having a width dimension W as a main surface. For example, the width dimension W is about 4 mm, and the thickness dimension is about 0.3 mm.

  In each of the high temperature superconducting coils 80a to 80h, as shown in FIGS. 1 to 3, the position of the high temperature superconducting wire 10 in the direction of the winding axis AX is kept approximately constant. For this reason, each of the high-temperature superconducting coils 80a to 80h has an outer dimension HT smaller than the dimension obtained by adding half the width dimension W to the width dimension W of the strip surface SP in the direction of the winding axis AX.

  The high temperature superconducting wire 10 includes, for example, a plurality of superconductor portions 12a, a sheath portion 12b, a laminate portion 11a, and a joint portion 11b. The superconductor portion 12a extends linearly. The sheath portion 12b covers the superconductor portion 12a. The pair of laminate portions 11a sandwich the sheath portion 12b. The pair of laminate portions 11a are joined to each other by a joint portion 11b. The material of the superconductor portion 12a is preferably, for example, a bismuth-based superconductor having a Bi-Pb-Sr-Ca-Cu-O-based composition. In particular, the atomic ratio of bismuth and lead: strontium: calcium: copper is approximately 2: A material containing the Bi2223 phase represented approximately by a ratio of 2: 2: 3 is optimal. The material of the sheath portion 12b is, for example, silver or a silver alloy. The material of the laminate part 11a is, for example, stainless steel. The material of the joint portion 11b is, for example, solder.

  Referring to FIG. 5, laminated high temperature superconducting coil 90 has a racetrack shape in a viewpoint along winding axis AX, that is, in a plan view. For this reason, the high-temperature superconducting coil 80a also has a racetrack shape. Specifically, the high-temperature superconducting coil 80a has a pair of straight line portions ST and a pair of curved line portions CR. The pair of straight lines ST and the pair of curved lines CR form a racetrack shape. The pair of straight line portions ST face each other across the winding axis AX and extend in parallel to each other. Each of high temperature superconducting coils 80b-80h also has a racetrack shape. For example, the length of the straight portion ST is about 1300 mm, and the radius of the curved portion CR is about 150 mm on the inner peripheral side and about 160 mm on the outer peripheral side.

  Further, with reference to FIGS. 6 and 7, the inclination of the strip surface SP (also referred to as a first strip surface) of the high temperature superconducting wire 10 in each of the high temperature superconducting coils 80a to 80h with respect to the winding axis AX will be described below.

  The strip surface SP (also referred to as a first strip surface) of the high temperature superconducting wire 10 forming each of the high temperature superconducting coils 80a, 80b, 80g and 80h is inclined at the central portion STa of the straight portion ST with respect to the winding axis AX. Yes. Specifically, as shown in FIG. 6, the strip surface SP is inclined so that the strip surface SP moves away from the winding shaft AX toward the end of the multilayer high temperature superconducting coil 90 in the direction of the winding shaft AX. This inclination is gradually reduced as the distance from the central portion STa increases in the boundary portion STb. For this reason, in the curved part CR connected through the central part STa and the boundary part STb, the inclination of the strip surface SP with respect to the winding axis AX is smaller than the inclination in the central part STa. Therefore, the maximum value of the angle between the strip surface SP and the winding axis AX in the pair of curved portions CR is smaller than the maximum value of the angle between the strip surface SP and the winding axis AX in the pair of straight portions ST.

  Preferably, in the curved portion CR, as shown in FIG. 7, the strip surface SP and the winding axis AX are parallel to each other. That is, the angle between the strip surface SP and the winding axis AX is zero. In this case, considering the tension in the extending direction of the superconducting wire 10, the main stress applied to the superconducting wire 10 may be only due to the twist of the superconducting wire 10 at the linear boundary STb. it can. Thereby, it is not necessary to provide a portion where the superconducting wire 10 is bent while being twisted.

  The strip surface SP (also referred to as a second strip surface) of the high temperature superconducting wire 10 forming each of the high temperature superconducting coils 80c to 80f and the winding axis AX are in the straight portion ST and the curved portion CR, that is, in the entire circumference. They are parallel to each other.

Next, the first comparative example will be described below.
Referring to FIG. 8, laminated high temperature superconducting coil 99 of the first comparative example is replaced with high temperature superconducting coils 80aZ, 80bZ, 80gZ and 80gZ instead of high temperature superconducting coils 80a, 80b, 80g and 80h of the present embodiment. 80 hZ. The high-temperature superconducting coils 80aZ, 80bZ, 80gZ, and 80hZ have a strip surface SP that is parallel to the winding axis AX over the entire circumference, like the high-temperature superconducting coils 80c to 80f of the present embodiment.

  Further, referring to FIG. 9, according to the simulation result of the magnetic field distribution in the xy plane having the y direction along the winding axis AX and the x direction from the winding axis AX toward the outer circumferential direction, the x component of the magnetic field vector, that is, the winding The perpendicular magnetic field with respect to the strip surface SP parallel to the axis AX increased as y increased.

  Referring to FIG. 10, average vertical magnetic field H applied to each strip surface SP of high temperature superconducting coils 80 a to 80 h at central portion STa (FIG. 5) of straight line portion ST of stacked high temperature superconducting coil 90 of the present embodiment is expressed as follows. The results calculated using the simulation results of the magnetic field distribution are shown on the right side of items a to h. Moreover, the same result in the laminated high temperature superconducting coil 99 (FIG. 8) of the first comparative example is shown on the left side of the items a to h. From this result, the average vertical magnetic field can be reduced by replacing each of the high-temperature superconducting coils 80aZ, 80bZ, 80gZ and 80hZ (FIG. 8) with the high-temperature superconducting coils 80a, 80b, 80g and 80h (FIG. 6). It was found that the high-temperature superconducting coils 80a and 80h located at the ends in the direction of the winding axis AX were large. In general, since the critical current increases due to the reduction of the vertical magnetic field, the critical current is replaced by replacing each of the high-temperature superconducting coils 80aZ, 80bZ, 80gZ and 80hZ (FIG. 8) with the high-temperature superconducting coils 80a, 80b, 80g and 80h (FIG. 6). It is considered that this effect is large in the high-temperature superconducting coils 80a and 80h located at the ends in the direction of the winding axis AX.

  Referring to FIG. 11, the result of calculating the AC loss L of each of the high-temperature superconducting coils 80a to 80h included in the laminated high-temperature superconducting coil 90 of the present embodiment using the simulation result of the average vertical magnetic field is item a. Shown on the right side of ~ h. In addition, the calculation result of the AC loss L of each of the high-temperature superconducting coils 80aZ, 80bZ, 80c to 80f, 80gZ, and 80hZ included in the multilayer high-temperature superconducting coil 99 of the first comparative example is calculated using the simulation result of the average vertical magnetic field. Shown on the left side of items ah. From this result, it is possible to reduce AC loss by replacing the high-temperature superconducting coils 80aZ, 80bZ, 80gZ and 80hZ (FIG. 8) with the high-temperature superconducting coils 80a, 80b, 80g and 80h (FIG. 6), respectively. It was found that the high-temperature superconducting coils 80a and 80h located at the ends in the direction of the axis AX were large.

  As described above, it has been found that, according to the present embodiment, it is possible to suppress a decrease in critical current as compared with the first comparative example. It was also found that an increase in AC loss can be suppressed.

Next, a second comparative example will be described.
Referring to FIG. 12, the high-temperature superconducting coil 89 of the second comparative example has a circular shape having an outer radius R, not a track shape. That is, the high-temperature superconducting coil 89 is composed only of a curved portion having a constant radius of curvature and does not have a straight portion.

  Referring to FIG. 13, strip surface SP of high temperature superconducting coil 89 is inclined with respect to winding axis AX.

Further, referring to FIG. 14, at an arbitrary position of high-temperature superconducting wire 10 of high-temperature superconducting coil 89, the distance between winding axis AX and the center position of high-temperature superconducting wire 10 (position indicated by a point in FIG. 14) is r ₀ , When the distance between the winding axis AX and the outer peripheral side end (upper right end in FIG. 14) of the high-temperature superconducting wire 10 is defined as r ₁ and the angle between the winding axis AX and the strip surface SP is defined as TH, the following equation (1) is obtained. It holds.

(W / 2) · sinTH = r ₁ −r ₀ (1)
Using the center position of the high-temperature superconducting wire 10 as a boundary, it is approximated that tensile stress occurs on the outer peripheral side and compressive stress occurs on the inner peripheral side. Since it is considered that the tensile stress has a greater influence on the deterioration of the electrical characteristics than the compressive stress, the strain on the outer peripheral side is particularly examined. The strain ε at the outer peripheral side end of the high-temperature superconducting wire 10 satisfies the following formula (2).

(2πr ₁ ) / (2πr ₀ ) = 1 + ε (2)
When r ₁ is eliminated from the equations (1) and (2), the following equation (3) is obtained.

r ₀ = (W · sinTH) / (2ε) (3)
If the upper limit of the strain ε is 0.002 (that is, the upper limit of strain is 0.2%) in securing the characteristics of the high-temperature superconducting wire 10, the allowable lower limit of the distance r ₀ is the angle TH of 10 °, 45 In each of ° and 80 °, they are 190 mm, 760 mm, and 1060 mm. Therefore, if the high-temperature superconducting coil 89 of the second comparative example is formed with the same radius of curvature as the high-temperature superconducting coil 80a of the present embodiment (for example, the radius of curvature of the inner peripheral portion of the curved portion CR is about 150 mm), It is considered that the distortion of the wire 10 becomes excessively large and the electrical characteristics are significantly deteriorated.

  As described above, it can be seen that according to the present embodiment as compared with the second comparative example, it is possible to avoid a remarkable deterioration of the electrical characteristics due to the distortion of the high-temperature superconducting wire 10.

The effects of the present embodiment will be summarized below.
According to the high temperature superconducting coil 80a (FIG. 6) of the present embodiment, the strip surface SP of the high temperature superconducting wire 10 has a portion inclined with respect to the winding axis AX. Thus, unlike the high-temperature superconducting coil 80aZ (FIG. 8) where all of the belt-like surfaces SP are parallel to the winding axis AX, the vertical magnetic field received by the high-temperature superconducting wire 10 from the magnetic field inclined with respect to the winding axis AX is reduced. The direction of the surface SP can be adjusted. Therefore, at least one of a decrease in critical current and an increase in AC loss can be suppressed.

  Further, the maximum value of the angle of the strip surface SP with respect to the winding axis AX is made smaller in the curved portion CR than in the straight portion ST. As a result, the stress of the high-temperature superconducting wire 10 is reduced as compared with the case where the band-shaped surface SP is inclined in the curved portion CR to the same extent as the straight portion ST. Therefore, since the distortion of the superconducting wire due to the stress is reduced, the remarkable deterioration of the electrical characteristics of the high temperature superconducting wire 10 can be prevented more reliably.

  From the above, according to the high-temperature superconducting coil 80a of the present embodiment, at least one of the decrease in critical current and the increase in AC loss is suppressed while avoiding remarkable deterioration of electrical characteristics due to distortion of the high-temperature superconducting wire 10. can do.

  Preferably, the strip surface SP and the winding axis AX are parallel to each other in the pair of curved portions CR. Thereby, the stress of the high temperature superconducting wire 10 can be further reduced. Therefore, the remarkable deterioration of the electrical characteristics due to the distortion of the high temperature superconducting wire 10 can be avoided more sufficiently.

  Preferably, high temperature superconducting coil 80a has outer dimension HT (FIG. 2) smaller than the dimension obtained by adding half the width dimension W to width dimension W (FIG. 4) of strip surface SP in the direction of winding axis AX. . Thereby, the shape of the superconducting coil can be made flat within an error range that is half of the width dimension W of the strip surface SP. That is, the coil can be made flat while suppressing distortion of the high-temperature superconducting wire 10.

  According to the laminated high temperature superconducting coil 90 (FIG. 6) of the present embodiment, the inclination with respect to the winding axis AX under a magnetic field distribution in which the inclination with respect to the winding axis AX in the lamination direction (inclination with respect to the y direction in FIG. 9) is not constant. The high-temperature superconducting coil 80a (having a large inclination of the band-shaped surface SP with respect to the winding axis AX) is disposed in a magnetic field region where the magnetic field is large, and the high-temperature superconducting coil 80d (the band-shaped surface SP with respect to the winding axis AX) By arranging the one having a small inclination or zero, the vertical magnetic field received by the high-temperature superconducting wire 10 can be reduced in a wider area. In other words, the belt-like surface SP can be roughly aligned with the magnetic field vector in a wider region. Therefore, at least one of a decrease in critical current and an increase in AC loss can be further suppressed.

  Further, since the belt-like surface SP is parallel to the winding axis AX in the high-temperature superconducting coil 80d, the winding operation of the superconducting wire for manufacturing the high-temperature superconducting coil 80d can be easily performed.

(Embodiment 2)
Referring to FIG. 15, laminated high temperature superconducting coil 90V of the present embodiment is replaced with high temperature superconducting coils 80a, 80b, 80g and 80h in the first embodiment, respectively. Have Each of the high-temperature superconducting coils 80aV, 80bV, 80gV and 80hV has a spacer 19 in the middle of winding of the high-temperature superconducting wire 10 in at least a part of the pair of straight line portions ST (FIG. 5). The spacer 19 has such a shape as to fill a gap between the high-temperature superconducting wire 10 located on the inner peripheral side where the inclination of the belt-like surface SP is small and the high-temperature superconducting wire 10 located on the outer peripheral side where the inclination of the belt-like surface SP is large. Have. FIG. 15 shows an example in which the inclination of the belt-like surface SP is zero on the inner peripheral side and about 45 ° on the outer peripheral side.

  Since the configuration other than the above is substantially the same as the configuration of the first embodiment described above, the same or corresponding elements are denoted by the same reference numerals, and description thereof is not repeated.

  According to the present embodiment, in at least a part of the pair of straight line portions ST (FIG. 5), the outer peripheral belt-like surface SP is more inward of the winding axis AX than the inner peripheral belt-like surface SP. Has a large slope. Thereby, the inclination of the strip surface SP of the high-temperature superconducting wire 10 can be changed so as to correspond to the magnetic field distribution in which the direction is more inclined with respect to the winding axis AX as the distance from the winding axis AX increases. Thereby, the vertical magnetic field received by the high temperature superconducting wire 10 can be reduced in a wider area. Therefore, at least one of a decrease in critical current and an increase in AC loss can be further suppressed.

  As shown in FIG. 15, the high-temperature superconducting coil has a higher number of turns in the inner peripheral side of the high-temperature superconducting wire 10, that is, in the portion of the high-temperature superconducting wire 10 where the inclination of the belt-like surface SP is small or zero. More may be done at 80 bV. In this case, as shown in FIG. 9, the influence of the vertical magnetic field can be reduced under a magnetic field distribution in which the vertical magnetic field tends to be smaller as it is closer to the center of the winding axis AX (the origin of FIG. 8).

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above-described embodiment but by the scope of claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

  10 High-temperature superconducting wire, 19 spacer, 80a to 80h, 80aV, 80bV, 80gV, 80hV High-temperature superconducting coil, 90, 90V Laminated high-temperature superconducting coil, AX winding axis, CR curved portion, SP strip surface, ST straight portion, STa center Part, STb boundary part.

Claims (5)

A high temperature superconducting coil formed by winding an oxide superconducting wire having a band-like surface around a virtual winding axis,
A pair of linear portions facing each other across the winding axis and extending parallel to each other,
The belt-like surface is inclined with respect to the winding axis in at least a part of the pair of straight portions, and further includes a pair of curved portions that form a racetrack shape together with the pair of straight portions,
The maximum value of the angle between the said fascia winding axis of the pair of curved portions, rather smaller than the maximum value of the angle between the said fascia in the linear portion of the pair winding axis, and the The high-temperature superconducting coil in which the strip surface and the winding axis are parallel to each other in a pair of curved portions . The high-temperature superconducting coil is in the direction of the winding axis, has a smaller outside dimension than the dimension of the dimension plus the half of the width to the width of the strip surface, the high temperature superconducting coil according to claim 1. Wherein at least a portion of the linear portion of the pair, than the fascia it is the inner circumferential side of the strip surface of the outer peripheral side has a greater inclination relative to the winding shaft, according to claim 1 or claim 2 The high-temperature superconducting coil described in 1. A laminated high temperature superconducting coil formed by laminating a plurality of high temperature superconducting coils,
A first high-temperature superconducting coil formed by winding an oxide superconducting wire having a first belt-like surface around a virtual winding axis;
The first high-temperature superconducting coil has a pair of straight portions facing each other with the winding axis therebetween and extending in parallel with each other, and the first belt-like surface is formed on at least a part of the pair of straight portions. Is inclined with respect to the winding axis, and the first high-temperature superconducting coil has a pair of curved portions that form a racetrack shape together with the pair of straight portions, and the pair of curved portions in the pair of curved portions The maximum value of the angle between the first belt-shaped surface and the winding shaft is smaller than the maximum value of the angle between the first belt-shaped surface and the winding shaft in the pair of linear portions, and In the curved portion, the first band-shaped surface and the winding axis are parallel to each other, and an oxide superconducting wire having a second band-shaped surface is formed by being wound around the winding axis. With high temperature superconducting coil
In the second high-temperature superconducting coil, the second high-temperature superconducting coil, wherein the second band-shaped surface and the winding axis are parallel to each other. 5. The stacked high temperature superconducting coil according to claim 4, wherein the first high temperature superconducting coil is disposed closer to an end side of the stacked high temperature superconducting coil than the second high temperature superconducting coil along the direction of the winding axis. Superconducting coil .

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