JPH05144635A - Current lead of oxide superconductor - Google Patents

Abstract

PURPOSE:To increase the mechanical strength by a method wherein an FRP reinforcement structure body is provided on the outer peripheral surface of a superconductor oxide in the title current lead using the superconductor oxide. CONSTITUTION:The specific position on an oxide superconductor 2 is covered with a prepreg 5 cut in required size to be held by upper and lower tables 4. The prepreg 5 is pressure-rolled by sliding the tales 4. Later, when heated, the resin impregnated in the prepreg 5 is melted down making the fiber and the oxide superconductor 2 bond onto each other to be formed into one body. Through these procedures, the reinforcement structure can be formed on the center peripheral surface of the superconductor oxide by an easy process within a short time.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to oxide superconductor current leads having a reinforcing structure.

[0002]

2. Description of the Related Art Oxide superconductors have the characteristics that they can obtain a superconducting state in a relatively high temperature range around the temperature of liquid nitrogen and have a low thermal conductivity at low temperatures. Therefore, it has been applied and developed as a material for a current lead for the purpose of feeding power to equipment used at extremely low temperatures.

On the other hand, since the oxide superconductor is a brittle material having a small mechanical strength, cracks and damages are likely to occur due to bending stress and impact force during processing or when used as a product. A current lead using an oxide superconductor is required to have a structure integrated with a reinforcing material that prevents damage and the like.

Conventionally, a means for reinforcing an oxide superconductor by using a metal material such as copper or silver has been adopted. However, when used as a current lead, such a metal material has a high thermal conductivity and a large amount of heat entering a cryogenic device, so that the characteristics of the oxide superconductor have not been fully utilized.

[0005]

Instead of using the above metal material for reinforcement, a material having a small thermal conductivity which does not impair the superconducting property is used so as to make use of the characteristics of the oxide superconductor. It is desirable to reinforce. Also, as a reinforcing material, it is easier to handle if its own weight is smaller,
In many cases, it is advantageous in that it is not damaged when subjected to an impact force.

An object of the present invention is to provide a current lead using an oxide superconductor with a lightweight, heat conductive and durable reinforcement.

[0007]

In order to solve the above problems, the present invention uses a lightweight and excellent strength FRP (fiber reinforced composite material) as a reinforcement of an oxide superconductor current lead. Carbon fibers, glass fibers, etc., which are usually used for FRP, have a thermal conductivity of 1
It is as small as 1/000, and F using these fibers
The thermal conductivity of RP is also small.

The oxide superconductor current lead of the present invention has a structure in which a sheet of glass fiber or the like impregnated with a resin (hereinafter referred to as a prepreg) is wound around an oxide superconductor and cured by heating to be integrated. This forms a reinforcing body.

The structure of the oxide superconductor current lead of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view in the circumferential direction in an example of the oxide superconductor current lead of the present invention, and FIG. 2 is a cross-sectional view in the axial direction. An FRP reinforcing portion 3 is provided on the outer circumference of the cylindrical oxide superconductor 2, and terminals are connected to the electrode portions at both ends of the oxide superconductor 2. In this example, a current lead using a cylindrical oxide superconductor is shown.
It can also be applied to the one using other bulk-shaped ones.

An example of a method of forming the reinforcing portion of the oxide superconductor current lead of the present invention will be described. FIG. 3 shows an example of the forming method by the tube winding method. A prepreg 5 cut to a required size is laid at a predetermined position of the oxide superconductor and sandwiched between the upper and lower tables 4. Slide the table 4 as shown by the arrow in the figure, and wind the prepreg while applying pressure. When a plurality of prepregs are wound or a plurality of prepregs are wound and laminated, the strength is increased. After that, when heated, the resin impregnated in the prepreg is melted and the fiber and the oxide superconductor are adhered to each other to form an integrated structure.

When the oxide superconductor current lead shown in FIGS. 1 and 2 is molded by the above method, the prepreg is cut into a width that leaves the terminal connection portions at both ends of the oxide superconductor, and the prepreg is applied with a table. Wrap while pressing. After that, the terminals are connected to both ends of the oxide superconductor to which the prepreg is adhered by heating by adhesion or soldering to complete. in this way,
The time required for the process is short, and a simple reinforcing means for the oxide superconductor current lead can be obtained.

As another method of forming the FRP reinforcing member on the oxide superconductor current lead, there is a FW (filament winding) method in which glass fiber or carbon fiber is wound around the outer periphery of the oxide superconductor and is reinforced with a resin.

When the FRP reinforcing body is formed by the FW method, since the oxide superconductor forming the current lead is generally in the shape of a curved surface such as a cylinder or a cylinder, the fiber is surrounded by a pin or groove. A fixing structure is required. It is like integrally molding the pins or winding a fiber through the pins or grooves around a superconductor formed by forming grooves and reinforcing it with resin. The fiber is wound around leaving a predetermined electrode portion for connecting the terminal.

The FW method requires a little more time and labor compared to the FRP manufacturing method using a prepreg. In advance, it is necessary to determine the electrode and terminal connection portions and provide a structure for fixing the reinforcing fiber when forming the oxide superconductor. It is difficult to select the reinforcing portion of the oxide superconductor after molding. Further, since the connection surface of the terminal is held, the reinforcing portion may be limited. When connecting the terminals, post-machining may be required to form the terminal insertion portion.

[0015]

The FRP-reinforced oxide superconductor current lead of the present invention has a small amount of heat penetration because of the small thermal conductivity of the FRP, is lightweight, and has the effect of obtaining excellent mechanical strength. In particular, the FRP reinforced oxide superconductor current lead, which forms a reinforcing structure using a prepreg, can form the reinforcing structure in a short time and with a simple process, and is used for post-machining for connecting terminals and fiber fixing. There is an advantage that the formation of a structure is unnecessary.

[Brief description of drawings]

FIG. 1 is a cross-sectional view in the circumferential direction of an example of an oxide superconductor current lead of the present invention.

FIG. 2 is a sectional view in the axial direction of an example of an oxide superconductor current lead of the present invention.

FIG. 3 is a diagram illustrating an example of a method for manufacturing an oxide superconductor current lead of the present invention.

[Explanation of symbols]

 1 terminal 2 oxide superconductor 3 FRP reinforcement 4 table 5 prepreg

Claims (2)

[Claims] 1. A current lead using an oxide superconductor, wherein an FRP reinforcing structure is provided on the outer peripheral surface of the oxide superconductor. 2. The FRP reinforcing structure is characterized in that a prepreg obtained by impregnating a sheet of reinforcing fibers with a resin is wound around an outer peripheral surface of an oxide superconductor and cured by heating to be integrated. The oxide superconductor current lead according to claim 1.