JP2006135060A - Superconductive magnet and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a superconductive magnet wherein a superconductor is rigidly fixed at a specified position and which is superior in workability of manufacture and disassembly, and to provide its manufacturing method. <P>SOLUTION: This method is used to manufacture a superconductive magnet by winding plural layers of superconductor 3 around a winding frame 1 with an interlayer sheet 2 in-between. In this case, adhesive agents 5 and 6 are applied to the surfaces of the superconductor 3, the winding frame 1 and the interlayer sheet 2, and they are fused and are made integral with them, so that the superconductor 3 is adhered to the winding frame 1 or the interlayer 2 for fixation. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a superconducting magnet used for a particle accelerator and the like and a method for manufacturing the same.

  Superconducting magnets used in particle accelerators, etc., require that the conductors in the coil be accurately arranged as designed in order to generate a magnetic field with the required accuracy. There is an example where is required. In addition, since many superconducting magnets are used after being cooled to a very low temperature, the coil is required to have a structure that does not cause any abnormalities such as peeling, cracking, and excessive strain with respect to the thermal stress generated by cooling.

  When the coil has a high current density and a large size, the generated magnetic field increases accordingly, so that a large electromagnetic force is generated and structural support and fixing are important. If the coil is not sufficiently fixed, a quench phenomenon may occur in which the superconducting state is broken when the conductor is slightly moved due to disturbance such as electromagnetic force, and the performance of the device cannot be exhibited. In addition, since the superconducting magnet used for the particle accelerator is exposed to radiation, the radiation resistance property of the material is also required.

  In the case of a superconducting magnet with two or more poles generally used for large particle accelerators, a cable called Rutherford type is formed by gathering several single-conductor superconducting conductors, twisting them, and then forming them into a trapezoid shape with a die. Use a conductor. In the case of coil molding, the cable conductor is formed into a bowl shape and is assembled around the beam through-hole to generate a necessary magnetic field (see Non-Patent Document 1 below). However, since the cable conductor is a conductor in which a plurality of single wires are stranded, the cross-sectional area becomes large, and this is applied to a superconducting magnet that is inevitably used at a large current.

  On the other hand, apart from the above, in the case of a superconducting magnet used at a small current, a round wire or a single wire of a square wire is used, but a saddle coil is formed and the conductors are aligned to improve the conductor position accuracy. There is currently no established method for efficient winding. Although it is not efficient, as a method of winding a single superconducting wire with high positional accuracy, there is a method of winding while directly bonding and fixing the conductor to the structure around the beam through hole with a winding machine capable of coordinate control . In this winding method, an acrylic instantaneous adhesive or an epoxy thermosetting resin is used as the adhesive. Furthermore, the support and fixing of the electromagnetic force accompanying the thermal stress and excitation during cooling of the coil depend on the adhesive strength of the adhesive at the time of winding or depend on the mechanical constraint from the coil outer peripheral side.

The superconducting magnet used with the above-mentioned small current is as shown in FIG. That is, a coil is formed by winding the superconducting conductor 3 while being bonded and fixed by a numerically controlled winding machine while sandwiching the interlayer sheet 2 around the structure 1 constituting the beam through hole. FIG. 8 is a detailed cross-sectional view showing a conductor portion. The interlayer sheet 2 and the superconducting conductor 3 are bonded and fixed by an instantaneous adhesive 9 applied between the superconducting conductor 3 and the interlayer sheet 2.
“Superconductivity Engineering” published by the Institute of Electrical Engineers, sold by Ohm, published on October 15, 1991, page 247

  In the superconducting magnet configured as described above, when the superconducting conductor 3 of the upper layer is disposed on the portion where the superconducting conductor 3 of the lower layer is not provided, the space 10 in which there is nothing directly below the upper conductor is formed. For this reason, the interlayer sheet 2 falls to the lower layer side, and the conductor position accuracy of the upper layer may deteriorate. Further, since the instantaneous adhesive 9 bonds the interlayer sheet 2 and the superconducting conductor 3 in a state close to point contact, there is a problem that sufficient adhesive strength cannot be secured. Furthermore, since there is no space 10 between the superconducting conductors 3, there is a problem that the rigidity of the coil itself as a structure is low and it cannot withstand thermal stress and electromagnetic force.

  Thus, in the case of a multi-layer coil, the interlayer sheet 2 falls into a portion where the superconducting conductor 3 is not arranged in the lower layer in the stage of winding, and the conductor position accuracy of the upper layer deteriorates. There is a problem that the position accuracy of the superconducting conductor 3 cannot be ensured as the winding proceeds to the upper layer. In addition, when the electromagnetic force becomes strong, the adhesive strength at the time of the support winding of the conductor is not sufficient, and there is a problem that it cannot withstand the thermal stress due to cooling and the electromagnetic force due to excitation. There is a problem that it cannot be applied to a superconducting magnet that uses.

In this way, when adopting a method of winding while superimposing a superconducting conductor directly on the structure around the beam through-hole with a coordinate controllable winding machine, the position accuracy of the superconducting conductor is the mechanical property of the winding machine. Although it can be ensured by the control accuracy, when an instantaneous adhesive is used for fixing the superconducting conductor, the adhesive strength is lowered at a very low temperature, and sufficient strength cannot be obtained. In addition, when bonded and fixed with an epoxy-based thermosetting resin, the strength at extremely low temperatures can be secured, but a certain thermosetting time is required, and it is necessary to wait for the adhesive in the winding to cure, and the winding speed is low. It drops significantly. In addition, with epoxy resin thermosetting adhesives, a strong molecular network is formed by the cross-linking reaction, so it does not flow even when reheated. There is.
Accordingly, an object of the present invention is to provide a superconducting magnet in which a superconducting conductor is firmly fixed at a predetermined position and has good workability in manufacturing and disassembling, and a manufacturing method thereof.

  According to a first aspect of the present invention, there is provided a method of manufacturing a superconducting magnet in which a superconducting conductor is wound in a plurality of layers by interposing an interlayer sheet around a winding frame, the surface of the superconducting conductor, the surface of the winding frame, and the interlayer sheet. The superconductive conductor is bonded and fixed to the winding frame or the interlayer sheet by applying an adhesive to the surface and fusing and integrating the adhesive.

  The invention of claim 5 includes a winding frame, a superconducting conductor wound around the winding frame in a plurality of layers via an interlayer sheet, a dummy conductor disposed between the superconducting conductors, and the winding frame. The interlayer sheet, the superconducting conductor, and the dummy conductor are provided with an adhesive that adheres at least two of them.

  According to the present invention, it is possible to provide a superconducting magnet having a superconducting conductor firmly fixed at a predetermined position and having good workability in manufacturing and disassembling, and a manufacturing method thereof.

An embodiment of the present invention will be described with reference to FIGS.
As shown in FIG. 1, a superconducting conductor 3 is wound around a beam through-hole structure 1 which is a winding frame by a winding machine capable of coordinate control (not shown). A dummy conductor 4 is disposed in a space between the superconducting conductor 3 and the superconducting conductor 3. As this dummy conductor 4, a superconducting conductor of the same type as that used for the coil is cut short. As shown in FIG. 2, the superconducting conductor 3 is wound in multiple layers with the interlayer sheet 2 interposed therebetween. As shown in FIG. 3, the superconducting conductor 3 presses and vibrates the superconducting conductor 3 from the upper part of the superconducting conductor 3 to the interlayer sheet 2 using the ultrasonic vibrator 8. The superconducting conductor 3 is firmly fixed with high positional accuracy by fusing and integrating the adhesive 6 applied onto the interlayer sheet 2 and the adhesive 5 applied around the conductor, which are heated by vibration friction. FIG. 4 is an enlarged cross-sectional view of a coil portion composed of two layers, an upper layer and a lower layer, formed through the bonding process of FIG. 3, and this coil portion is formed from an epoxy resin containing a silica filler in the space between the conductors 3. The filling resin 7 is filled. The epoxy resin is a general bisphenol A type and has a molecular structure as shown in FIG.

  In actual winding, the ultrasonic transducer 8 passes while pressing on the superconducting conductor 3, and a winding method is adopted in which the superconducting conductor 3 is bonded and fixed to the interlayer sheet 2. A phenoxy resin having a molecular structure shown in FIG. 5 is used for the adhesive 5 around the superconducting conductor 3 and the adhesive 6 on the surface of the interlayer sheet 2. Regarding the application of the adhesive to the superconducting conductor 3, the same method as that described in Japanese Patent No. 2597724 can be used.

  In the superconducting magnet of the present embodiment configured as described above, adhesives 5 and 6 made of phenoxy resin are applied to the periphery of the superconducting conductor 3 and the interlayer sheet 2, and the ultrasonic vibrator 8 is used. The adhesives 5 and 6 are melted by the frictional heat generated by pressing the superconducting conductor 3 against the interlayer sheet 2. The superconducting conductor 3 is firmly fixed at a predetermined position with high accuracy by integrating the phenoxy resin layer in the process of melting and re-solidification by passing through the ultrasonic vibrator 8 while being pressed.

  Since the phenoxy resin is thermoplastic, it can be remelted unlike a thermosetting resin, so that it is possible to correct the winding and improve workability. Moreover, the melting and re-solidification of the phenoxy resin converges in a short time, so that the winding work can be speeded up. Moreover, since the phenoxy resin has a high adhesive strength and has a sufficient adhesive strength even at an extremely low temperature, the conductor does not peel off due to a decrease in the adhesive strength caused by cooling to an extremely low temperature.

  In addition, by placing a dummy conductor 4 having the same dimensions and the same adhesive applied in a large gap between the superconducting conductors 3, the interlayer spacer 2 between the upper layers does not fall to the lower layer side, and the lower layer to the upper layer. The position accuracy of the superconducting conductor 3 in increasing the winding is increased. Further, by arranging a conductor made of the same material as that of the superconducting conductor 3 as the dummy conductor 4, the rigidity as the coil structure is enhanced. Although a superconducting conductor is used as the dummy conductor 4 in the present embodiment, a GFRP (glass fiber reinforced plastic) spacer or the like having an equivalent cross-sectional dimension can be used instead.

  Finally, the space between the superconducting conductors 3 is filled with a filler resin 7 having a thermal contraction rate close to that of the superconducting conductors 3 by silica filler, and has a structure that can withstand the thermal stress and large electromagnetic force accompanying cooling and excitation. When an epoxy resin is used as a filler between the superconducting conductors 3 bonded and fixed with a phenoxy resin, the phenoxy resin and the epoxy resin are similar in molecular structure, so their physical properties are similar and the compatibility is good. When resin materials are used in combination, problems such as peeling that occur at the interface do not occur. Therefore, it is possible to firmly fix the superconducting conductor 3. In addition, both epoxy resin and phenoxy resin have high radiation resistance.

  As shown in FIGS. 1, 2, 3 and 4, the superconducting magnet of the present embodiment is obtained by applying phenoxy resin to the periphery of the superconducting conductor 3, the outer periphery of the beam through-hole structure 1, and the surface of the interlayer sheet 2. The coil is formed by bonding and fixing, so that the positional accuracy of the superconducting conductor 3 during winding can be ensured, the workability is good, and high bonding strength can be obtained.

  Further, by vibrating the superconducting conductor 3 with the ultrasonic vibrator 8, the adhesives 5 and 6 are fused by using the frictional heat generated between the superconducting conductor 3 and the interlayer sheet 2 that is the adherend. Local heating and adhesion that does not affect the other parts can be performed at high speed, and stable superconducting conductor position accuracy can be ensured and workability can be improved.

  Further, by disposing a dummy conductor 4 having the same size and the same adhesive in a large space between the superconducting conductors 3, the dimensional accuracy of the upper layer side conductor is deteriorated due to the interlayer sheet 2 dropping to the lower layer side. The rigidity as an overall coil structure is also improved by preventing and reducing the space without a conductor.

  Further, the gap between the conductors is filled with a filling resin 7 of an epoxy resin containing filler, thereby fixing the position of the superconducting conductor 3 and fixing against the thermal stress and electromagnetic force. Epoxy resin is similar in molecular structure to phenoxy resin. No peeling phenomenon at the resin interface occurs. Epoxy resins and phenoxy resins are materials with high resistance to radiation, and therefore have high radiation resistance as coils and superconducting magnets.

  Although the above description has been made with respect to a superconducting magnet of a saddle coil, the present invention can also be applied to a superconducting magnet of a solenoid type or the like.

The perspective view which shows the superconducting magnet of embodiment of this invention. The partial detail sectional view of the coil part of the superconducting magnet of an embodiment of the invention. The conceptual diagram which shows the adhesion process by the ultrasonic heating at the time of winding of the superconducting magnet of embodiment of this invention. The fragmentary detailed sectional view which shows arrangement | positioning of the adhesive agent and filling resin of the coil part of the superconducting magnet of embodiment of this invention. The figure which shows the chemical structure of the phenoxy resin used as an adhesive agent in the superconducting magnet of embodiment of this invention. The figure which shows the chemical structure of the epoxy resin which comprises filling resin in the superconducting magnet of embodiment of this invention. Sectional drawing which shows the conventional superconducting magnet. Detailed sectional drawing of the coil part of the conventional superconducting magnet.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Beam through-hole structure, 2 ... Interlayer sheet, 3 ... Superconducting conductor, 4 ... Dummy conductor, 5 ... Adhesive apply | coated around the conductor, 6 ... Adhesive apply | coated to the interlayer sheet surface, 7 ... Filling between conductors Resin, 8 ... Ultrasonic vibrator, 9 ... Instant adhesive, 10 ... Space.

Claims (6)

  In a method of manufacturing a superconducting magnet in which a superconducting conductor is wound in a plurality of layers with an interlayer sheet interposed around a winding frame, an adhesive is applied to the surface of the superconducting conductor, the surface of the winding frame, and the surface of the interlayer sheet. A method of manufacturing a superconducting magnet, wherein the superconducting conductor is bonded and fixed to the winding frame or the interlayer sheet by fusing and integrating the adhesive.   The method of manufacturing a superconducting magnet according to claim 1, wherein the adhesive is made of a thermoplastic resin.   The method of manufacturing a superconducting magnet according to claim 1, wherein the adhesive is made of phenoxy resin.   2. The method of manufacturing a superconducting magnet according to claim 1, wherein ultrasonic vibration is used as a heating means for fusing the adhesive.   A winding frame, a superconducting conductor wound around the winding frame in a plurality of layers via an interlayer sheet, a dummy conductor disposed between the superconducting conductors, the winding frame, the interlayer sheet, and the superconducting conductor And a superconducting magnet comprising an adhesive for adhering at least two of the dummy conductors to each other. 6. A superconducting magnet according to claim 5, wherein a gap between the superconducting conductor or the dummy conductor is filled with an epoxy resin containing a filler.

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