JP2016046380A - Superconducting electromagnet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a superconducting electromagnet in which peeling of a wound tape wire can be suppressed.SOLUTION: In a superconducting electromagnet 1 according to the present embodiment, sticking of a tape wire 4 and an impregnation material 5 to each other is suppressed since a lubricant 3 is interposed between the tape wire 4 and the impregnation material 5. Therefore even if the tape wire 4 and the impregnation material 5 are shrunk with different thermal shrinkage when the superconducting electromagnet 1 is cooled, acting of force on the tape wire 4 can be suppressed. Further, the tape wire 4 to be wound around a bobbin 2 is coated with the lubricant 3 in each circumference of the tape wire 4, so that acting of force on the tape wire 4 can be uniformly suppressed in each circumference of the tape wire 4. Therefore, peeling of the wound tape wire 4 can be suppressed.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a superconducting electromagnet.

  2. Description of the Related Art Conventionally, a superconducting electromagnet is known in which a superconducting coil is formed by winding a tape wire having a superconducting layer laminated thereon, and the tape wire is shaped by an impregnating material such as resin. The tape wire is firmly bonded to the impregnating material when the impregnating material is cured.

  When such a superconducting electromagnet is cooled, a force acts on the tape wire due to the difference in thermal shrinkage between the tape wire and the impregnating material. As a technique for suppressing the peeling of the tape wire due to this force, for example, a technique described in Patent Document 1 is known. In Patent Document 1, a superconducting tape wire and an insulating tape coated with a resin are superposed to form a composite tape, and the composite tape is wound around a winding core so that the inner / outer diameter ratio approaches a predetermined size. Sometimes a superconducting electromagnet is described that weakens the adhesion between adjacent composite tapes.

JP 2010-267835 A

  However, in the superconducting electromagnet as described above, it is intended to suppress the tape wire from peeling between the composite tapes with weakened adhesive force. On the other hand, for the part where the adhesive force is not weakened, the tape wire is separated separately. It is necessary to suppress by this method.

  Then, an object of this invention is to provide the superconducting electromagnet which can suppress peeling of the tape wire wound.

  In order to solve the above-described problems, a superconducting electromagnet according to the present invention includes an annular winding frame, a tape wire wound around the winding frame and at least a substrate and a superconducting layer laminated, and a winding frame embedded with the tape wire The tape wire is coated with a lubricant that suppresses the tape wire and the impregnating material from sticking to each other around the winding frame.

  According to the superconducting electromagnet according to the present invention, since the lubricant is interposed between the tape wire and the impregnation material, adhesion between the tape wire and the impregnation material is suppressed. For this reason, even when the superconducting electromagnet is cooled and the tape wire and the impregnating material shrink due to different heat shrinkage rates, it is possible to suppress the force from acting on the tape wire. Furthermore, since the lubricant is applied to each circumference of the tape wire wound around the winding frame, it is possible to uniformly suppress the force acting on the tape wire around each circumference of the tape wire. Therefore, peeling of the wound tape wire can be suppressed.

  In the superconducting electromagnet according to the present invention, the tape wire may be coated with a lubricant over the entire circumference of a cross section perpendicular to the winding direction of the tape wire. Thereby, peeling of a tape wire can be suppressed over the perimeter of a cross section perpendicular | vertical with respect to the winding direction of a tape wire, and a lubricant can be easily apply | coated to a tape wire.

  In the superconducting electromagnet according to the present invention, the thermal conductivity of the lubricant may be higher than the thermal conductivity of the impregnating material. Thereby, even if the lubricant is interposed between the tape wire and the impregnating material, the heat transfer efficiency between the tape wire and the impregnating material can be maintained.

  According to the present invention, peeling of the wound tape wire can be suppressed.

It is a top view which shows the superconducting electromagnet which concerns on embodiment of this invention. It is a fragmentary sectional view along the II-II line of FIG. It is a figure which shows the laminated structure of a tape wire. It is a fragmentary sectional view of the superconducting electromagnet which concerns on a comparative example.

  Hereinafter, an embodiment of a superconducting electromagnet according to the present invention will be described in detail with reference to the drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 is a plan view showing a superconducting electromagnet according to an embodiment of the present invention. FIG. 2 is a partial cross-sectional view taken along line II-II in FIG. 1 and schematically shows a tape wire wound around a winding frame of a superconducting electromagnet. FIG. 3 is a view showing a laminated structure of tape wires. As shown in FIGS. 1 to 3, the superconducting electromagnet 1 includes a winding frame 2, a tape wire 4 coated with a lubricant 3, and an impregnation material 5. The superconducting electromagnet 1 is, for example, a superconducting cyclotron, a deflecting electromagnet in a charged particle beam therapy apparatus, a silicon single crystal pulling apparatus (MCZ), a magnetic resonance imaging apparatus (MRI apparatus), a nuclear magnetic resonance apparatus (NMR apparatus), etc. The present invention can be applied to various devices using the conductive electromagnet 1.

  The winding frame 2 is for winding the tape wire 4 and holding it in a coil shape. The winding frame 2 has an annular shape, and a concave portion that is accommodated while the tape wire 4 is wound is provided over the entire circumference of the winding frame 2 on the outer peripheral side. Specifically, when the winding frame 2 is viewed in a cross section perpendicular to the circumferential direction of the winding frame 2 (state shown in FIG. 2), the back plate 2a disposed on the inner peripheral side and both ends of the back plate 2a And side plates 2b and 2c extending toward the outer peripheral side.

  The tape wire 4 is wound around the winding frame 2 to form an annular superconducting coil. The tape wire 4 is configured by laminating a first portion 6 including a substrate 8 and a second portion 7 including a layer formed on the substrate 8. The second portion 7 is a portion where peeling is likely to occur from the surface of the substrate 8. The tape wire 4 is formed so that the thickness in the stacking direction is about 0.1 mm to 0.2 mm and the width is about 4 mm to 12 mm. Note that the lubricant 3 is applied to the outer surface of the tape wire 4. The lubricant 3 will be described later.

  The first portion 6 is configured by laminating a substrate portion metal layer 9 on a substrate 8, and the substrate portion metal layer 9 includes a silver layer 10 in contact with the substrate 8, a copper layer 11 in contact with the silver layer 10, Consists of. The substrate 8 is formed to have a thickness of about 50 μm, the silver layer 10 has a thickness of about 1.8 μm, and the copper layer 11 has a thickness of about 20 μm.

  The second portion 7 is in contact with the substrate 8, the buffers 12 to 16 are stacked on the opposite side of the substrate portion metal layer 9, the superconductive layer 17 is stacked so as to be in contact with the buffer 16, and the superconductive layer 17 is The film-forming part metal layer 18 is laminated so as to be in contact therewith. The film forming portion metal layer 18 includes a silver layer 19 in contact with the superconducting layer 17 and a copper layer 20 in contact with the silver layer 19. The buffers 12 to 16 and the superconducting layer 17 are formed by a film forming process such as vapor deposition or sputtering. The buffers 12 to 16 are formed to have a thickness of about 0.2 μm, the superconductive layer 17 has a thickness of about 1 μm, the silver layer 19 has a thickness of about 2 μm, and the copper layer 20 has a thickness of about 20 μm.

  The superconducting layer 17 is composed of an RE123-based superconducting layer. The RE123-based superconducting layer refers to an oxide superconducting layer containing rare earth elements (RE) such as gadolinium and yttrium, barium, and copper in a ratio of 1: 2: 3. The superconducting layer 17 is wound in a ring as a part of the tape wire 4 to form a superconducting coil, and is brought into a superconducting state by being cooled to a predetermined temperature or lower by a refrigerator (not shown). The superconducting layer 17 on which the superconducting coil is formed has an annular shape with a rectangular cross section, and generates a strong magnetic field by being fed by a power source (not shown).

  The impregnating material 5 is provided on the winding frame 2 so as to embed the tape wire 4, and ensures thermal conductivity between the tape wire 4 formed with the superconducting coil and the refrigerator and the tape wire 4 formed with the superconducting coil. Keep shape. The impregnating material 5 is made of a material that hardens from a flowing state such as gel or liquid, and is made of, for example, epoxy resin, wax, cyanoacrylate (instant adhesive), candle brazing material, or the like. The impregnating material 5 does not need to apply the above-mentioned material, and other materials may be applied as long as the thermal conductivity with the superconducting coil can be secured and the superconducting coil can be shaped. By impregnating the tape wire 4 in the winding frame 2 when the impregnating material 5 is in a flowing state, the impregnating material 5 enters a gap generated when the tape wire 4 is wound, thereby ensuring good thermal conductivity can do. Further, since the impregnating material 5 is cured after entering the gap generated when the tape wire 4 is wound, the tape wire 4 on which the superconducting coil is formed can be retained.

  Subsequently, the lubricant 3 will be described.

  The lubricant 3 is applied to the tape wire 4 so that the tape wire 4 and the impregnating material 5 are lubricated and the tape wire 4 and the impregnating material 5 are prevented from adhering to each other. In particular, the lubricant 3 is applied to the tape wire 4 on each circumference wound around the winding frame 2. Thereby, unlike the case where the lubricant 3 is applied after the tape wire 4 is wound a plurality of times, the lubricant 3 is always interposed between the tape wire 4 and the impregnating material 5. .

  Here, the lubricant 3 is applied to the tape wire 4 in each circumference to be wound, for example, the tape wire 4 shown on the innermost side in FIG. When the tape wire 4 shown in Fig. 2 is the second round and similarly, the third and subsequent rounds (not shown) are continued, it means that the lubricant 3 is applied to each round portion of the tape wire 4. Or at the time of manufacture, it means the state in which the lubricant 3 is applied over the entire length of the tape wire 4 to be wound.

  As the lubricant 3, a material having high thermal conductivity and being difficult to adhere to a material (for example, epoxy resin) constituting the impregnating material 5 can be used, and for example, a heat conductive grease can be used. In particular, it is preferable to use a thermal conductive grease in which the thermal conductivity of the lubricant 3 is higher than that of the impregnating material 5. Specifically, the lubricant 3 such as Apiezon (registered trademark) N grease can be applied. Thereby, since the lubricant 3 is interposed between the tape wire 4 and the impregnating material 5, good thermal conductivity can be ensured even if the tape wire 4 and the impregnating material 5 are not in direct contact.

  Note that the lubricant 3 is not necessarily limited to those that are distributed for the purpose of lubrication, and includes a wide variety of lubricants that can prevent the tape wire 4 and the impregnating material 5 from being fixed. For example, the lubricant 3 may be distributed as a mold release agent, or may be distributed as a wax or candle brazing material.

  Then, the manufacturing method of the superconducting electromagnet 1 is demonstrated. First, the impregnating material 5 in a fluidized state before curing is poured into a recess provided on the outer circumference side of the annular winding frame 2 over the entire circumference. Next, the tape wire 4 having the surface coated with the lubricant 3 is wound around the winding frame 2 into which the impregnating material 5 is injected. At this time, even if a gap occurs in the wound tape wire 4, the impregnating material 5 enters the gap because it is in a state of flowing. Next, the impregnating material 5 is cured over time or by a predetermined method such as heating. Accordingly, since the impregnating material 5 is cured after entering the gap generated when the tape wire 4 is wound, the tape wire 4 on which the superconducting coil is formed can be retained. Further, since the tape wire 4 is impregnated in the impregnating material 5 with the lubricant 3 applied to the surface over the entire length, the tape wire 4 and the impregnating material 5 are wound around the winding frame 2. In each circumference, the lubricant 3 is interposed.

  In addition to the manufacturing method described above, the superconducting electromagnet 1 is first wound around the winding frame 2 with the impregnating material 5 attached to the tape wire 4 having the lubricant 3 applied to the entire surface. May be manufactured. In this case, the impregnating material 5 may be additionally injected into the winding frame 2 after winding. Also in this method, since the impregnating material 5 enters and cures in the gap generated when the tape wire 4 is wound, the tape wire 4 on which the superconducting coil is formed can be retained. Further, the tape wire 4 and the impregnating material 5 are in a state in which the lubricant 3 is interposed in each circumference where the tape wire 4 is wound around the winding frame 2.

  Then, the effect | action by the structure of the superconducting electromagnet 1 is demonstrated.

  As described above, the tape wire 4 is mainly composed of metal or the like, whereas the impregnating material 5 is composed of epoxy resin or the like, so that the tape wire 4 and the impregnating material 5 have different thermal shrinkage rates. Therefore, as shown in FIG. 2, there is a difference between the thermal contraction (arrow A1) of the tape wire 4 when the superconducting electromagnet 1 is cooled and the thermal contraction (arrow A2) of the impregnating material 5, and the superconducting electromagnet. Thermal stress is generated with the cooling of 1. As a result, a force in the direction of separating the second portion 7 from the first portion 6 acts particularly between the second portion 7 and the impregnating material 5.

  Here, in the superconducting electromagnet 1, since the lubricant 3 is interposed between the tape wire 4 and the impregnating material 5, the lubricant 3 flows even when the superconducting electromagnet 1 is cooled. Therefore, generation of thermal stress can be suppressed. Therefore, peeling can be suppressed in each circumference of the wound tape wire 4.

  Next, the superconducting electromagnet 100 according to the comparative example will be described. FIG. 4 is a diagram schematically showing a tape wire wound around a winding frame of a superconducting electromagnet according to a comparative example.

  As shown in FIG. 4, in the superconducting electromagnet 100 according to the comparative example, the lubricant 3 is not interposed between the tape wire 4 and the impregnating material 5. For this reason, when the impregnating material 5 is cured, the impregnating material 5 is firmly bonded to the tape wire 4. Here, the thermal stress generated by the difference between the thermal contraction (arrow A1) of the tape wire 4 when the superconducting electromagnet 100 is cooled and the thermal contraction (arrow A2) of the impregnating material 5 causes the second portion 7 to A force in the direction of separating the second portion 7 from the first portion 6 acts with the impregnating material 5. In the superconducting electromagnet 100 according to the comparative example, since the lubricant 3 is not interposed between the tape wire 4 and the impregnating material 5, the second portion 7 is peeled off from the first portion 6, and the superconducting coil. May be damaged.

  As described above, according to the superconducting electromagnet 1 according to the present embodiment, since the lubricant 3 is interposed between the tape wire 4 and the impregnating material 5, the tape wire 4 and the impregnating material 5 Sticking is suppressed. For this reason, even when the superconducting electromagnet 1 is cooled and the tape wire 4 and the impregnating material 5 shrink due to different thermal shrinkage rates, it is possible to suppress the force from acting on the tape wire 4. Furthermore, since the lubricant 3 is applied to each circumference of the tape wire 4 wound around the winding frame 2, it is possible to uniformly suppress the force acting on the tape wire 4 on each circumference of the tape wire 4. . Therefore, peeling can be suppressed in each circumference of the wound tape wire 4.

  In the superconducting electromagnet 1 according to the present invention, the lubricant 3 is applied to the tape wire 4 over the entire circumference of the cross section perpendicular to the winding direction of the tape wire 4. Thereby, while being able to suppress peeling of the tape wire 4 over the perimeter of a cross section perpendicular | vertical with respect to the direction where the tape wire 4 is extended, the lubricant 3 can be easily apply | coated to the tape wire 4. FIG.

  In the superconducting electromagnet 1 according to the present invention, the thermal conductivity of the lubricant 3 is higher than that of the impregnating material 5. Thereby, even if the lubricant 3 is interposed between the tape wire 4 and the impregnating material 5, the heat transfer efficiency between the tape wire 4 and the impregnating material 5 can be maintained.

  The present invention is not limited to the above embodiment. For example, although the tape wire 4 is provided with both the substrate part metal layer 9 and the film forming part metal layer 18, only the film forming part metal layer 18 may be provided.

  Further, the number of turns around which the tape wire 4 is wound is not particularly limited as long as it is a plurality of times, and can be freely changed depending on the usage purpose of the superconducting electromagnet 1 and the thickness of the tape wire 4. In FIG. 2, the tape wire 4 is wound so as to be aligned in the radial direction, but may be wound side by side in the axial direction, or may be wound while being shifted in the axial direction or the radial direction. .

  The annular winding frame 2 has a cross-sectional shape perpendicular to the circumferential direction of the winding frame 2, and side plates 2 b and 2 c erected from the both ends of the back plate 2 a toward the outer peripheral side. However, the cross-sectional shape of the winding frame 2 may be different as long as the impregnating material 5 can be provided so as to wind the tape wire 4 and embed the tape wire 4.

  Further, the lubricant 3 may not be applied to the tape wire 4 over the entire circumference of the cross section perpendicular to the winding direction of the tape wire 4, and at least as shown in FIG. The lubricant 3 may be applied in a range (region R) from the outer peripheral surface of the second portion 7 of the tape wire 4 to the upper surface and the lower surface to the position past the upper surface and the lower surface. Even in this case, since the lubricant 3 is interposed between the second portion 7 and the impregnating material 5, peeling can be suppressed in each circumference of the wound tape wire 4. In addition, when the lubricant 3 is not applied to the tape wire 4 and the tape wire 4 and the impregnating material 5 are fixed, the second portion 7 and the substrate 8 out of the upper surface and the lower surface of the second portion 7 At the boundary position, stress concentration due to the difference in thermal shrinkage between the tape wire 4 and the impregnating material 5 is likely to occur. On the other hand, since the lubricant 3 is applied to a position past the upper surface and the lower surface of the second portion 7, it is possible to suppress an excessive force from acting on the tape wire 4 due to stress concentration. By the above, peeling can be suppressed in each circumference | surroundings of the tape wire 4 wound.

  DESCRIPTION OF SYMBOLS 1 ... Superconducting electromagnet, 2 ... Winding frame, 3 ... Lubricant, 4 ... Tape wire material, 5 ... Impregnation material, 8 ... Substrate, 17 ... Superconducting layer.

Claims (3)

An annular reel,
A tape wire wound around the winding frame and laminating at least a substrate and a superconducting layer;
An impregnating material provided on the reel so as to embed the tape wire,
A superconducting electromagnet in which the tape wire is coated with a lubricant that prevents the tape wire and the impregnating material from adhering to each other around the winding frame.   The superconducting electromagnet according to claim 1, wherein the lubricant is applied to the tape wire over the entire circumference of a cross section perpendicular to the winding direction of the tape wire.   The superconducting electromagnet according to claim 1 or 2, wherein a thermal conductivity of the lubricant is higher than a thermal conductivity of the impregnating material.

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