JPH11168008A - Manufacture of oxide superconducting coil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing an oxide superconducting coil through which manufacturing steps can be simplified greatly. SOLUTION: A coil is formed by winding an oxide superconducting wire material and a ribbon-like glass tape so as to be overlapped upon one another. The glass tape is formed by bonding glass fibers which are arranged in one direction with a semi-hardened thermosetting resin. Then, the coil is subjected to heat treatment, such that the thermosetting resin is cured and the oxide superconducting wire material and the glass tape are solidified into an integral body. In this case, the glass tape has a tensile strength of 450 MPa or higher in the semi-hardened condition, and 750 MPa or higher in the cured condition, and has a dielectric breakdown voltage of 3.5 KV/0.1 mm or higher.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a superconducting coil, and more particularly to an improvement in a method for manufacturing an oxide superconducting coil suitable for a high magnetic field to which a large electromagnetic force is applied.

[0002]

2. Description of the Related Art When an oxide superconducting wire is coiled and used as an insert coil for generating a high magnetic field, a large electromagnetic force is applied to this coil. However, since the strength characteristics of the oxide superconducting wire are low, the characteristics are deteriorated by this electromagnetic force.

Further, there is a problem that the coil is quenched by the movement of the superconducting wire due to electromagnetic force.

In order to prevent such a problem from occurring, conventionally, the coil is fixed as follows.

First, an oxide superconducting wire is wound together with a reinforcing wire such as a SUS wire into a coil shape.
Next, the work of fixing each wire in the coil after winding is performed. Specifically, for example, after placing a coil housed in an impregnation case in a vacuum vessel and evacuating, a thermosetting resin such as an epoxy resin is filled in the case, and a resin is filled in a gap between each wire. After impregnating with the liquid, releasing the vacuum as necessary and applying pressure, finally taking out the case filled with the thermosetting resin from the vacuum container, heat-treating it at a predetermined temperature to heat the resin. Each wire is fixed by curing.

[0006]

However, the above-mentioned conventional coil manufacturing method has the following problems.

(A) It is necessary to impart electrical insulation to SUS wire or the like used as a reinforcing wire. (B) Since the coil is housed in an impregnation case, it is difficult to make the coil compact. (C) When the resin is impregnated, a container for accommodating the resin and special equipment for performing vacuum evacuation are required, and the production cost is increased. (D) The resin is interposed between the superconducting wires constituting the coil. It takes a long time to impregnate, and (e) it is very difficult to sufficiently impregnate the resin between the superconducting wires in view of the gap between the wires and the viscosity of the resin.

The present invention solves the above-mentioned problems in the conventional method of manufacturing an oxide superconducting coil, and eliminates the work of electrically insulating a reinforcing wire and the operation of impregnating a resin with a method of manufacturing an oxide superconducting coil. The purpose is to provide.

[0009]

In order to achieve the above-mentioned object, in the present invention, an oxide superconducting wire and a semi-cured glass tape obtained by bonding glass yarns with a thermosetting resin are superposed. After the coil is formed by winding, the coil is subjected to a heat treatment to cure the thermosetting resin, whereby the oxide superconducting wire and the glass tape are solidified integrally.

In the above invention, it is preferable to use a glass tape made of a semi-cured glass tape in which glass yarns arranged in parallel are bonded with a thermosetting resin.

Further, as the glass tape, a glass tape having a tensile strength of 450 MPa or more in a semi-cured state, 750 MPa or more in a cured state, and having a dielectric breakdown voltage of 3.5 kV / 0.1 mm or more may be used. preferable.

As such a glass tape, a PG tape manufactured by Arisawa Seisakusho Co., Ltd. (Joetsu City, Niigata Prefecture) can be used.

This PG tape is a flat semi-cured (semi-cured) glass tape having insulating properties, flexibility and moderate adhesive strength, in which alkali-free glass yarns are arranged in parallel and bonded with a thermosetting resin. By heating,
The bonded resin is melted, and when further heated, has a property of being cured and integrated. Further, since this glass tape is not a textile tape, it has high strength and high impact force. Specifically, PG402 (F
This tape is, for example, 10 mm × 0.33 mm and is 550 MPa in a semi-cured state.
As described above, the cured state has a tensile strength of about 950 MPa.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, first, a tape-shaped oxide superconducting wire and a ribbon-shaped glass tape to be described later are overlapped and wound in a coil shape. At this time, in order to suppress the stress load applied to the oxide superconducting wire, it is preferable to wind the wire around a glass tape.

The ribbon-shaped glass tape used is a flat composite material in which glass fibers such as glass yarns are aligned in one direction to form a core, and each glass fiber is bound with an epoxy resin or a polyester resin. is there. Accordingly, the tape is electrically insulating as a whole, and has a flexibility and an appropriate adhesive strength at room temperature because the semi-cured thermosetting resin forms a matrix. Then, when the heat treatment is performed, the thermosetting resin is once fluidized, and finally converted into a non-melting resin cured product, and the whole becomes a high-strength, high-impact insulator.

Next, heat treatment is performed on the coil. The thermosetting resin of the ribbon-shaped glass tape once melts and penetrates into the gaps between the respective wires of the coil, and is then thermoset to fix the wires.

If the temperature during the heat treatment is too low, the molten state of the resin does not appear, so that the resin is impregnated into the gaps between the wires.
In other words, the wire cannot be fixed and hardened, and if the temperature is too high, foaming of the resin and rapid thermal hardening occur, and the wire fixing effect cannot be obtained. In addition, even if the temperature is appropriate, if the processing time is too short, the melting of the resin and the penetration into the gap between the wires do not sufficiently proceed, and if the processing time is too long, the effect of fixing the wire becomes sufficient. However, it is time consuming and reduces productivity.

From the above, the temperature and time of the heat treatment depend on the properties of the ribbon-shaped glass tape to be used, but for example, the preheating temperature of the coil frame is 70 to 100 ° C.
As the curing temperature of the epoxy resin, 150 × 3 to 15 hours (PG402) can be adopted.

[0019]

EXAMPLES Bi-based (2212) manufactured by silver sheath method
Phase) Superconducting tape and ribbon-shaped glass tape (PG40
After superimposing 2), the resultant was wound into a double puncture to form a coil.

The coil is placed in a constant temperature premises at a temperature of 150 ° C.
Heat treatment was performed for 0 hour to produce a superconducting coil having the following specifications.

Coil inner diameter: 40 mm Coil outer diameter: 100 mm Coil height: 50 mm Number of punctures: 5 Total number of turns: 566 Total wire length: 125 m Operating current: 100 A Generated magnetic field: 0.8 T (4.2 K) , OT) On the other hand, as a result of comparison with a superconducting coil of the same specification manufactured using an SUS wire as a reinforcing wire and an epoxy resin as an impregnating resin, there was no significant difference in coil characteristics when no external magnetic field was applied. The coil characteristics (stability) in a high magnetic field have been improved. This is considered to be due to the resin being sufficiently impregnated between the wires. In addition, the time required to manufacture the coil has been significantly reduced since no impregnation step is required.

[0022]

As is clear from the above description, in the method of manufacturing a superconducting coil of the present invention, the steps of performing the electrical insulation on the reinforcing wire and the step of impregnating the resin as in the prior art are omitted. The manufacturing process is greatly simplified, and the manufacturing cost is greatly reduced. Further, since the case for impregnation is not used unlike the conventional case, the size of the coil itself can be reduced. Furthermore, since the resin can be sufficiently impregnated between the wires, the coil characteristics can be improved.

Claims (3)

[Claims] 1. A coil is formed by laminating and winding an oxide superconducting wire and a semi-cured glass tape in which glass yarn is bonded with a thermosetting resin, and then subjecting the coil to heat treatment. A method for manufacturing an oxide superconducting coil, wherein the thermosetting resin is cured to solidify the oxide superconducting wire and the glass tape integrally. 2. The method for manufacturing an oxide superconducting coil according to claim 1, wherein the glass tape is a semi-cured glass tape in which glass yarns arranged in parallel are bonded with a thermosetting resin. 3. The glass tape is 450MP in a semi-cured state.
3. The method for producing an oxide superconducting coil according to claim 1 or 2, having a tensile strength of 750 MPa or more in a hardened state and a dielectric breakdown voltage of 3.5 kV / 0.1 mm or more. .