JPH02309613A - Supporting method for superconductor coil - Google Patents

Abstract

PURPOSE:To reduce friction heat and hence avoid temperature rise even when there is produced sliding between a superconducting coil and a supporter by bringing only the neighbourhood of the center of the outer peripheral surface of the superconducting coil into contact with the supporter when the coil is not excited, increasing a contact surface between the superconducting coil outer peripheral surface and the supporter as an excitation current is increased, and bringing substantially the entire surface of the coil into contact with the supporter upon completion of the excitation. CONSTITUTION:Although electromagnetic force is sustained in the vicinity of the center of an outer peripheral surface 8 of a superconducting coil upon the starting of excitation of the superconducting coil 1, any sliding between the coil and a supporter produces less friction heat because the electromagnetic force is small in itself. The electromagnetic force is increased in the course of the excitation but a contact area is also increased, so that a significant increase of the stress on the outer peripheral surface 8 of the superconducting coil can be avoided. At the time when the excitation of the superconducting coil 1 is completed, the uniform electromagnetic force is exerted over the entire surface of the semiconducting coil outer peripheral surface 8, so that the upper limit of the force can sharply be reduced. Hereby, any sliding between the superconducting coil 1 and the supporter 2 produces less friction heat to suppress the temperature rise of a superconducting wire. Thus, a stable performance superconducting coil 1 for which quenching is unlikely to occur is yielded.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a superconducting coil made by winding four superconducting wires into a rectangular cross-section and fixing them with impregnation, such as an on-board superelectric wind coil for a magnetic levitation railway. This relates to a support method.

[Conventional technology]

Conventional on-vehicle superelectric field coils for magnetic levitation railways Superconducting wires with a low copper ratio are wound in a racetrack shape as shown in Figure 5, and MAj! I am using one that has been impregnated and fixed with IJ. And so far m?
A method has been developed in which a floating blade is obtained by arranging the iti coil and its peripheral equipment in the positional relationship shown in Fig. 6 and using the induced repulsive force with the normal conducting coil in the orbit (for example, see Journal of the Japan Society of Mechanical Engineers, No. 81817, No. 1353). - pages 1359, Railway Research Institute Report No. 2@No. 6, pages 44-52, etc.) In Fig. 6, the superconducting coil 1 is in a liquid helium container for cooling to an extremely low temperature (
Covered by an electromagnetic force support 2 that also serves as an inner tank),
It is housed in a heat insulating container 3. The smaller the distance #H from the center of the cross section of the superconducting coil l to the center of the cross section of the normal conducting coil 4 for levitation, the tighter the T&magnetic coupling between the two becomes, and the larger the levitation blade when the vehicle is running. Therefore.

It is necessary to shorten the portion other than the effective gap as much as possible to make 11 smaller. Regarding the cross section of the superconducting coil,
If the IiT products are equal, the rectangular h can be made smaller than the circular h, as shown in Figure 7.

This is advantageous for shortening H in FIG. In addition to this reason, a rectangular cross section allows the maximum experienced magnetic field of a superconducting coil to be smaller than a circular cross section, and winding work is easier.

Superconducting coils with a rectangular cross section are used as onboard superconducting coils for floating railways.

By the way, when current is applied to the racetrack type superconducting coil, electromagnetic force as shown by the eighth arrow is applied to the superconducting coil 1 due to the interaction between the magnetic field generated by the superconducting coil itself and the current, and the superconducting coil 4 is about to be expanded. This electromagnetic force cannot be supported by the rigidity of the superconducting coil itself.

Some mechanical reinforcement support is required. Compared to the conventional method As shown in FIG. 9, a superconducting coil 1 is surrounded by a flat support 2,
It supported electromagnetic forces. outside the superconducting coil)? The support that holds the fJ plane is made of a highly rigid material, such as stainless steel, from the perspective of making 11 in Figure 6 as short as possible, but it must be designed to be as thin as possible so that its yield stress does not fall below the electromagnetic stress at Miff. There is.

With such a support structure, when the superconducting coil is energized, the superconducting coil expands in the direction of the electromagnetic force shown in FIG. 8, the outer circumferential surface 8 of the superconducting coil shown in FIG. Trying to extend in the rotational direction. Then, since the rigidities of the superconducting coil 1 and the support body 2 are different, slippage occurs between the superconducting coil outer circumferential surface 8 and the support body 2 due to the difference in the amount of deformation as the excitation current increases. Further, when the vehicle is running, the electromagnetic excitation force that the superconducting coil receives causes a slight sliding vibration between the outer circumferential surface 8 of the superconducting coil 8 and the support 2.

(Problem to be Solved by the Invention) When a superconducting coil, which is attached to a flat support before excitation as shown in FIG. 9, is excited, the superelectric field coil 1 and the support 2 are deformed as shown in FIG. Superconducting coil outer surface 8
The stress distribution becomes as shown by the arrow in FIG. That is,
Compressive stress concentrates at ends A and B of the outer circumferential surface of the superconducting coil, and near the center of the outer circumferential surface of the superconducting coil, the supporting body hardly supports electromagnetic force, or in extreme cases, the supporting body is separated. The situation is as follows. Therefore, if there is slippage between the superconducting coil and the support during excitation, the I
Since the aI heat is also concentrated at the corner of the outer circumferential surface of the superconducting coil, the temperature of the superconducting wire in this area does not rise.<,P! There is a problem in that the temperature exceeds the field temperature and causes a normal conduction transition. If even a part of a coil wound with a superconducting material having a small copper ratio undergoes a normal conduction transition, this will propagate to the entire superconducting coil, making it impossible to conduct electricity.

[Means to solve the problem]

In order to solve the above-mentioned problems, one aspect of the present invention is that the outer circumferential surface of a superconducting coil and a support body are in contact with the support body only at the vicinity of the center of the outer circumferential surface of the superconducting coil when not excited.

When the excitation current increases and the electromagnetic force increases,
The contact surface between the K coil outer circumferential surface and the support body also increases.

The super 11! This paper proposes a method for supporting conductive coils.

[Operation] When the superconducting coil starts excitation, the electromagnetic force is supported near the center of the outer circumferential surface of the superconducting coil, but since the uf force itself is small, even if slippage occurs, the frictional heat is small. Although the force increases, the contact surface also increases, making it possible to avoid a sudden increase in stress on the outer peripheral surface of the superconducting coil.

When the excitation of the superconducting coil is completed, a uniform t iff force acts on the entire outer circumferential surface of the superconducting coil.

The maximum value can be significantly reduced compared to the case where the present invention is not applied. Therefore, even if slippage occurs between the superconducting coil and the support, the frictional heat is small and the temperature rise of the superconducting wire is suppressed, so that -quenching is less likely to occur and a superconducting coil with stable performance can be obtained.

〔Example〕

Embodiments of the present invention will be specifically described based on the drawings.

FIG. 1 shows one embodiment of the present invention, in which a shows a non-excited state. When the electromagnetic force acting on the support is applied as a uniformly distributed load when the excitation is completed, the bending shape is shown (Fig. 2b). Therefore, before excitation, only the center of the outer peripheral surface 8 of the superconducting coil is the support 2. However, as the excitation current increases, the curvature of the support 2 is depressed as shown in Figure 1 (C), and when the excitation is completed, the support 2 deforms into a flat plate as shown in Figure 1 C. The compressive stress on the outer circumferential surface 8 of the conducting coil is approximately equally distributed as shown by the arrows.

FIG. 3 shows two other embodiments of the present invention. This fruit 8! li
In the example, an arcuate cross-section spacer 9 having a curved surface on one side and a flat surface on the other side is sandwiched between the super TIER coil outer circumference w8 and the support body 2. In this example.

Since the manufacture of the support body 2, which involves welding work, and the manufacture of the arcuate cross-section spacer 9 can be performed independently, dimensional control during manufacture is easy.

FIG. 4 shows another embodiment of the present invention. A flat plate spacer 10 having a Young's modulus equal to or higher than that of the support is attached between the support and the superconducting coil. This flat plate spacer 1O makes it possible to equalize the compressive stress on the outer circumferential surface 8 of the superconducting coil even before the excitation is completed.

〔Effect of the invention〕

According to the support structure for a superconducting coil according to the present invention.

Since the maximum stress on the outer peripheral surface of the superconducting coil during excitation is suppressed, even if slippage occurs between the superconducting coil and the support, the frictional heat is small and the temperature rise is low.

Quenching is less likely to occur (superconducting coils that exhibit stable performance can be obtained).

[Brief explanation of the drawing]

FIG. 1 shows one embodiment of the method for supporting a superconducting coil according to the present invention, in which a diagram shows a state when the coil is not excited, and a diagram b shows a state when the exciting current is increasing. C is a diagram showing the state when excitation is completed, Figure 2 explains the deflection when applying evenly distributed loads to a beam fixed at both ends, a is a diagram showing the state with no load applied, and b is a diagram showing a state in which a uniformly distributed load is applied. 3 and 4 are views showing other embodiments of the present invention, and FIG. 5 is a view showing an example of a race-trunk type superconducting coil.
Figure 6 is a diagram showing the cross-sectional structure of a magnetic levitation railway vehicle and track, Figure 7 is a diagram showing a cross-sectional comparison of superconducting coils, and Figure 8 is a diagram showing the electromagnetic force that acts when the racetrack coil is energized. 9 is a diagram showing a conventional method of supporting a superconducting coil, and FIG. 10 is a diagram showing deformation of electromagnetic force when energized in a conventional method of supporting a mix coil. 1.--Super 1 conductive coil, 2.--Support,
3...-Insulation/Container, 4...Normal conductive coil for levitation, 5-Bogie-6...Car body,
7... Orbit, 8... Superconducting coil outer peripheral surface, 9-... Arcuate cross section spacer, 10...
・・Flat plate spacer, 11・・・・Both ends fixed beam, A, B
-・-・-End of outer surface of superconducting coil Patent applicant Railway Technical Research Institute Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10

Claims (4)

[Claims] (1) Regarding the electromagnetic support of a superconducting coil in which a superconducting wire is wound into a rectangular cross-section and fixed with an impregnating agent, when it is not excited, only the center of the outer circumferential surface of the superconducting coil is in contact with the support, and the exciting current A method for supporting a superconducting coil, characterized in that the contact area between the outer circumferential surface of the superconducting coil and the support increases as the superconducting coil increases, so that almost the entire outer circumferential surface of the superconducting coil comes into contact with the support upon completion of excitation. (2) Claim 1, characterized in that the cross-sectional shape of the support in contact with the outer circumferential surface of the superconducting coil before excitation has a curved shape protruding toward the outer circumferential surface of the superconducting coil.
A method for supporting a superconducting coil as described in . (3) An arcuate cross-sectional spacer having a flat cross-sectional shape on one side and a convex curved surface on the other side is sandwiched between the superconducting coil and the support so that the convex curved surface is on the side of the superconducting coil,
A method for supporting a superconducting coil according to claim 1. (4) A superconductor according to claims 1 to 3, characterized in that a flat plate spacer having a Young's modulus equal to or higher than that of the support is attached to the outer peripheral surface of the superconducting coil. How to support the coil.