JPH03184215A - Superconductive wire - Google Patents

Abstract

PURPOSE:To obtain a superconductive wire whose insulating thread coiled helically on the wire are hard to shift and whose insulation is hard to deteriorate by forming ruggedness on the surface of the wire. CONSTITUTION:A superconductive wire with a pillar cross-section shape is manufactured by four rolls and pillar dies and ruggedness 5 is formed on the four planes of the wire by net-knurling machining. When Kevlar threads prepared by bundling fillaments 4 are coiled helically on the rough surface, fillaments 4 of the Kevlar threads get in the caved parts 5 of the rough surface and thus the Kevlar threads become hard to shift. In this way, the insulating threads coiled helically on the wire become hard to shift on the surface of the wire by forming ruggedness 5 on the wire surface and insulation property can be improved.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to improvements in superconducting wires.

[Conventional technology]

The insulation of superconducting wires used in superconducting coils that are immersed in cooling is generally coated with an insulating varnish such as formal and then baked. On the other hand, indirect cooling type superconducting coils require impregnation with resin such as epoxy to improve cooling of the coil. Superconducting wires insulated with metal are used. This superconducting wire is, for example,
It is manufactured as follows. That is, a superconducting wire with a round cross section is rolled with four rolls or passed through a rectangular die to form a rectangular superconducting wire, and Kevlar thread is tightly wound helically in the longitudinal direction of the wire around the outer periphery of the superconducting wire.

[Problem to be solved by the invention]

For superconducting wires insulated by winding threads such as glass or Kevlar, the insulating threads on the surface of the wires are wound in the process of being wound onto a bobbin by a take-up machine or winding machine immediately after insulation processing, and in the coil @ wire process. A force tends to shift in the longitudinal direction.

Incidentally, the metal surface roughness of the wire manufactured by the above-mentioned method corresponds to JIS MJ, 3S to 65, and has an extremely smooth surface. Therefore, the coefficient of friction between the insulating thread and the metal surface of the wire becomes small, causing the insulating thread to shift and exposing the metal surface of the wire, resulting in a problem that the insulation performance deteriorates.

[Means and actions to solve the problem]

The present invention provides a superconducting wire that solves the above problems, and is characterized in that the superconducting wire is formed by helically winding an insulating thread in the longitudinal direction of the superconducting wire, and the surface of the wire is provided with irregularities. It is something to do.

By providing unevenness on the surface of the wire in this way, the helically wound insulating thread becomes difficult to shift on the surface of the wire, improving insulation performance.

〔Example〕

Hereinafter, the present invention will be explained based on Examples.

A superconducting wire with a rectangular cross section was produced using four rolls and a rectangular die, and a twill low left process was applied to the four sides of the wire to form irregularities.

The results of measuring the surface roughness thus obtained are shown in FIG. According to this result, the peak of the roughness curve (1) (
The difference H between 2) and the valley (3) was 12±5−. On this rough surface, 200 filaments with an equivalent diameter of 12μ were bundled.
When Duur's Kevlar thread was wound helically, the filaments (4) of the Kevlar thread were stuck in the recesses (5) on the rough surface, as shown in Figure 2, making it difficult for the Kevlar thread to slip off.

In this example, the wire surface was roughened by knurling, but the same effect could be obtained by hairline processing.

〔Effect of the invention〕

As explained above, according to the present invention, since the surface of the wire is provided with irregularities, it is possible to obtain a superconducting wire that is less susceptible to insulation deterioration when the insulating thread helically wound on the wire surface is dislodged. It has a positive effect.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a roughness curve of the wire surface roughness of an embodiment of the superconducting wire according to the present invention, and FIG. 2 is a partial cross-sectional view of the superconducting wire wound with Kevlar yarn. l...Roughness curve, 2...Mountain, 3...Valley,
4...Filament, 5...Recess.

Claims (1)

[Claims] A superconducting wire in which an insulating thread is helically wound in the longitudinal direction of a superconducting wire, characterized in that the surface of the wire has irregularities.