JPH0715847B2 - Method for manufacturing superconducting coil bandage - Google Patents

Description

TECHNICAL FIELD The present invention relates to an improvement in a method for manufacturing a superconducting coil bandage.

(Prior art and its problems) Conventional superconducting magnets for accelerators and the like have a center pipe (1), a saddle type coil (2), as shown in FIG.
(2 '), center post (3), (3'), end spacers (4), (4 '), etc., which are assembled into a superconducting coil unit (5) as shown in FIG. Further, as shown in FIG. 5, an FRP bandage (6) is formed on the surface of the coil, and further an iron return yoke (7) is formed to form a superconducting magnet.

Since the coils (2) and (2 ') are formed by two coils, one is a top coil and the other is a bottom coil. Since this bandage sufficiently tightens the coil and at the same time transmits the electromagnetic force acting on the coil to the outer return yoke (7) during excitation, it must be integrated with the return yoke without any gap. For this reason, the bandage is required to have a high accuracy of outer diameter.

Conventionally, the bandage is produced by winding a high-strength thread or tape such as glass, polyester, or Kepler on the surface of the coil and the spacer while applying sufficient tension. It is a method of winding while applying a resin such as epoxy with excellent characteristics to cure the epoxy resin to form FRP, and then machining the outer surface to obtain the required outer diameter accuracy.

The FRP bandage formed by the above method integrates the thread or tape whose resin is a strength member, and the wire material of the coil, and also infiltrates between the wire materials of the coil to integrate the wire materials. there were. When this superconducting magnet is cooled by liquid helium and excited, the resin cracks due to cooling strain and electromagnetic stress, and the resin in contact with the wire moves the wire, causing the superconducting state to collapse and normal conduction to be achieved. It causes a so-called quench, which causes a shift, and there are drawbacks that the number of times the magnet is trained is increased and sufficient performance is not achieved.

(Means for Solving Problems) The present invention has been conceived in view of the above problems. The resin is applied while winding the FRP tension member in order to tighten the superconducting coil, and the resin is cured to form FRP. In the method of manufacturing a superconducting coil bandage,
Without impregnating the resin on the inner layer of the bandage,
Only the tension member is wound, only the outer layer of the bandage
A method for producing a superconducting coil bandage, which is characterized by forming FRP.

As the above tension member, glass, polyester, yarn or tape of Kepler or the like is used, and as the resin, epoxy resin is used.

As a superconductor, Nb ₃ Sn monolithic conductor is wound in a racetrack shape, and it is a superconductor that is heat-treated after press-molding into a saddle shape.Other than this, V ₃ Ga or NbTi may also be used directly. It may be wound around.

The center post and end spacers prevent quenching due to movement of the wire during excitation, and must be in contact with the coil without any gap. As a material, G-FRP, ceramic, etc., which are excellent in non-magnetic property, electric insulation, and low temperature characteristics are preferable, and stainless steel, cupro nickel, etc. having high electric resistance may be used after being insulated.

The method of assembling the superconducting coil by the above parts is the same as the conventional method shown in FIG. 4. However, according to the present invention, the coil bandage formed on the surface of this superconducting coil unit is formed with the bandage inner layer portion (8) as shown in FIG. In (), only the tension member is wound without impregnating the resin, and the tension member is wound while the resin is applied only to the bandage outer layer portion (9) to form the FRP only in the bandage outer layer portion.

The winding of the coil bandage of the present invention is carried out while maintaining a constant tension and may be done manually, but it is usually wound by a winding machine and the resin is applied manually or automatically by a brush or the like. is there.

(Example) An example of the present invention will be described below.

As shown in Fig. 2, on a center pipe of 132 mmφ x 850 mm
Using a superconducting coil unit in which a Nb ₃ Sn monolithic conductor was formed into a saddle shape and then heat treated, the Kevlar thread (10) was attached to the bobbin (1
1) Roll out, back tension roll (12), (1
2 ') and then the coil unit (5).

The back tension roll was a grooved roll having an outer diameter of 100φ and a length of 300 mm, and was helically wound 5 to 10 times by two rolls. The Kevlar yarn was wound around the coil unit (5) using 8500 denier (thickness: about 1 mmφ) with a tension of 50 kg / mm ² or more.

The pinch roll (13) is a roll for preventing the roll (12 ') and the Kevlar yarn from slipping, and the Kevlar yarn is pressed against the roll 12' by a spring, an air cylinder or the like.

(14 ') is a powder brake for applying a braking torque to the roll (12), and the current of the powder brake can be set by the power supply device (15).

As shown in FIG. 4, the coil unit (5) has a shape such that it is not fixed, and it is necessary to integrate each member during Kevlar winding, so tighten as shown in FIG. The ring (16) is integrated for tightening.

The tightening rings were arranged on the unit (5) at axial distances of 50 mm each. The axial length (thickness) of the tightening ring is also 50 mm.

In FIG. 2, the coil unit (5) integrated with the tightening ring was rotated by an appropriate driving device to wind the Kevlar yarn around the valley between the tightening rings.

The Kevlar layer having a thickness of 5 mm in contact with the coil was wound only with the Kevlar thread without resin impregnation, and the upper layer (5 mm) was wound while applying a room temperature curable epoxy with a brush. Next, the tightening ring was removed and the same bandage was applied.

After FRP is formed on the outer layer of the bandage by curing the epoxy resin, the outer periphery of this FRP layer is uniformly processed by a lathe.
The state shown in the figure was used. After that, although not shown, a return yoke of low carbon iron for preventing a leakage magnetic field at the time of excitation was assembled to form a superconducting magnet.

(Effect) Since the inner layer portion of the superconducting coil bandage according to the present invention is not impregnated with epoxy resin, even if a crack occurs in the outer layer epoxy resin during cooling or operation of this superconducting magnet, the inner layer portion contacting the coil is Since this is not impregnated with epoxy resin, this bandage acts to mitigate the movement of the coil wire and it is difficult to cause quenching, and as a result, the number of trainings can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view of a superconducting coil bandage of the present invention,
FIG. 2 is a perspective view illustrating a method for manufacturing a superconducting coil bandage according to the present invention. FIG. 3 is a perspective view illustrating components of a conventional superconducting coil, FIG. 4 is a perspective view of a conventional superconducting coil unit, and FIG. 5 is a cross-sectional view of a conventional coil bandage. 1 ... Center pipe, 2 and 2 '... Coil, 3 and 3'
... Center post, 4, 4 '... End spacer, 5
…… Electromotive coil unit, 6 …… Bandage, 7 ……
Return yoke, 8 ... bandage inner layer, 9 ... bandage outer layer, 10 ... Kevlar thread, 11 ... bobbin, 12,
12 '…… Back tension roll, 13 …… Pinch roll, 14 …… Powder brake, 15 …… Power supply unit, 16 ……
Tightening ring

Claims (1)

[Claims] 1. A method for manufacturing a superconducting coil bandage in which a resin is applied while winding a tension member of the FRP to tighten the superconducting coil, and the resin is cured to form an FRP. In the method, an inner layer portion of the bandage is impregnated with the resin. A method for manufacturing a superconducting coil bandage, characterized in that only the tension member is wound without being applied, and the tension member is wound while the resin is applied only to the outer layer portion of the bandage to form the FRP only on the outer layer portion of the bandage.