JPH02133115A - Manufacture of arcuate race track shaped coil - Google Patents

Abstract

PURPOSE:To obtain a superconducting coil excellent in stability by winding a wire round a straight race track-shaped coil, then, pressing an arcuate project ing die in contact with the coil and reducing the distance between both end parts while tension is given to the wire. CONSTITUTION:An inside forming projection die 8 and a forming projection die 9 are moved integrally and a projecting part having a prescribed radius of curvature is brought into contact with the straight parts 6, 6' of the coil 5 and pressed gradually. At the same time, in such consideration that no loose ness occurs or no excessive tension is given on a superconducting wire compos ing the coil 5, the distance MN between the centers of the cylindrical plates 2, 3 are reduced gradually to be formed into an arcuate race track shaped coil 11. Then, the inner and the outer peripheral surface of the coil 11 are fixed, inserted into a heating furnace, heated, cured and integrated. Thus, the looseness and the excessive tension, etc., do not occur to obtain the superconducting coil excellent in stability.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method of manufacturing an arc-shaped racetrack coil.

[Conventional technology]

In synchrotrons that accelerate or accumulate charged particles such as electrons and protons, dipole electromagnets are used to apply Lorentz force to the charged particles and cause them to follow circular or arcuate orbits.

Usually, this bipolar electromagnet is an arcuate racetrack coil (11) wound with superconducting wire shaped as shown in Figure 4.
are arranged above and below the point where the charged particle beam is caused to draw an arcuate trajectory.

Such an arcuate racetrack coil (1l) generally consists of two linear racetrack coils with both ends semicircular and two straight sections connecting them, as shown in Figure 7. In order to give the charged particle beam a bending angle θ with a predetermined radius of curvature R, the straight line portions are formed into an arc shape with a radius of curvature R and an angle of θ at the center of curvature 0 in the same direction within the plane in which these straight line portions are formed. This is what I did.

The above-mentioned arcuate racetrack coil is manufactured, for example, by the following method.

As shown in FIG. 7, both ends are semicircular and have a uniform width W, and the center line of the width is within the range of the bending angle θ of the charged particle beam determined by the coil design. Using a winding form (l3) with a radius of curvature R relative to the center of curvature point O, one end of the superconducting wire at the beginning of the winding is fixed to the winding form (13) with an appropriate fixing jig, and then the required number of turns is sequentially determined. Then, by winding the required number of layers, an arcuate racetrack type coil (11) is manufactured.

By the way, when the above-mentioned coil is used as a superconducting electromagnet, the wire of the coil is subjected to Lorentz force by its own magnetic field. For this reason, if the wire is not fixed enough, it will move and
The superconducting state is destroyed and the state shifts to normal conduction.

Therefore, in order to prevent this, when forming a coil, the wire is usually wound with tension applied to the wire. To explain this using the case shown in FIG. 7 above, when applying tension to the wire and winding it around the outer peripheral surface of the arc-shaped winding form (l3), the convex portion of the outer peripheral surface, that is, the TRI. tlV. In the vS part, the wire is wound into a winding type (l3
). However, at the concave portion of the outer circumferential surface, that is, the ST section, tension is applied to the wire, so the S point and T
Since the points are stretched straight, the wire has a winding form (1
3), the coil is separated from the ST portion, making it impossible to obtain the desired coil shape. The following methods are available to deal with this.

First, [A] When winding the wire, once the ST section is stretched straight, a press mold (l4) having a convex surface with the same curvature as the arc ST is
) to obtain the necessary circular arc shape for the wire, and then when winding the next wire on top of that wire, first remove the pressing die (14), then wind it, and then press the pressing die (14) again. 14). Following the same procedure, the wire is wound a predetermined number of turns, and then the entire wire is bonded with resin or the like to fix the wire to each other to produce the arcuate race 1/rack type coil.

Or [mouth] When winding wire rods in any layer without gaps, press a plurality of identically shaped pressing dies (14') having a thickness equal to or less than the thickness of the wire rods onto the winding die (13) for each turn. ,1
A method of fixing each layer with resin.

[Problem to be solved by the invention]

However, in the above method [A], since the pressing die (14) is once removed from the winding die (13) during the next winding of the wire, the wire becomes loose, which spreads in the longitudinal direction of the wire. For this reason, even if tension is applied to the wire for winding, sufficient tension is not actually applied, resulting in instability during operation.

Furthermore, an imbalance occurs in the tension inside the coil, causing significant deformation of the coil unit, making it difficult to incorporate it into an iron core or coil former. Furthermore, since the coil shape is determined by the stamping die, the same number of stamping dies as the number of layers is required, resulting in high cost.

In addition, the method described above requires a large number of stamping molds, which increases the cost and also increases the time required for fixing with the resin, making the delivery period extremely long.

Furthermore, as another method for fixing the wire along the ST part of the winding form (13) shown in FIG.
The publication describes a method in which a wire rod having a thermosetting resin layer on the outer periphery is wound while being pressed onto a winding form using a heated roller. However, this method requires time for the resin to harden, so it is difficult to apply tension to the wire rod. In addition, winding the wire would require a very long manufacturing time, making it impractical.

[Means to solve the problem]

In view of this, as a result of various studies, the present invention solves the conventional problems and provides a method for manufacturing a high-performance arcuate racetrack coil in a short period of time and at low cost.

That is, the present invention provides a method for manufacturing an arcuate racetrack coil, in which, after winding a wire into a linear racetrack coil, arcuate convex molds each having a predetermined radius of curvature are formed on two parallel straight sections. The wire rods at both ends of the coil are pressed together in the same direction, and at the same time, without moving the wire rods in the winding direction, the distance between the two ends is reduced while applying tension to the wire rods by stretching the wire rods at both ends of the coil. It is characterized by this.

[Effect]

In this way, the straight sections of the straight racetrack coil are pressed in the same direction by two convex molds having the desired radius of curvature, while applying tension to the wires while decreasing the distance between the ends of the coil. The reason for press forming is that it is possible to form an arcuate racetrack coil in a predetermined shape with tension acting on the wire.

After that, in order to assemble this coil into a coil support structure while maintaining its shape and the tension applied to the wire, the press die and other jigs used for the above-mentioned forming are not removed from the arc-shaped racetrack coil, and the wire is attached to the coil. These jigs may be used as part of the magnet by incorporating them into an electromagnet with tension applied, or the wire may be coated with an insulating material treated with epoxy repreg, and then the above molding may be performed.
The entire coil may be inserted into a heating furnace while maintaining its shape and tension state, heated and cured, and then the coil may be taken out and incorporated into an electromagnet.

Also, when press forming a straight section, the wire rods at both ends of the coil are not moved in the winding direction for the following reason.If they are moved, the tension will change between the wire rods on the outer and inner circumferences of the arc section. This is because not only does it become difficult to mold, but also it becomes impossible to obtain a coil with uniform characteristics.

That is, as shown in FIG. 8(a), the center distance 00 is RXθ
A linear racetrack coil (5) is formed by winding a tape-shaped conductor with a thickness t in n turns around cylindrical plates (2) and (3) with a radius r separated by 5
) is press-formed with a radius of curvature R so that the angle between the center of the cylindrical plate O゜,0゛ and the center of curvature 0 is θ, as shown in Fig. 8 (opening).
), compare the lengths of the first conductor from the innermost circumference of the coil. For convenience, each part of the coil is numbered as shown in the figure.

In Fig. 8 (mouth), line segment A'B'C' on the inner circumferential side
The length D' is equal to the straight line length AB in FIG. 8(a), as shown in the following first equation. Further, the arc length ε゛H゜ on the outer peripheral side of FIG. 8 (mouth) is equal to the length l of the line segment εFGI+ in FIG. 8 (a), as shown in the second equation.

L=2X (r+iXt) Xθ/2 + (R-r-iXt)
= (R + r + ixt) .

〔Example〕

Next, one embodiment of the present invention will be described.

As shown in Figure 1, two cylindrical plates (2
) and (3) were provided so that their center-to-center distances could be moved by an appropriate drive device (not shown), but not rotated in the circumferential direction.

Then, a glass stave prebrigged with epoxy resin was wrapped around the NbTi superconducting wire of 1.8 mm height x 1.2 mm width as an insulating material, and the finished dimensions of the cross section of the wire were 1.9 mm high x 1.3 mm wide. , one end of this superconducting wire (4) is fixed to one cylindrical plate (2), and the wire (4) is moved downward between it and the other cylindrical plate (3), that is, the base (
1) Laminated from the side upwards and then wound 14 turns to form the first layer. Next, the continuous wire (4) is similarly wound 14 turns on top of it to form the second layer, and the other end of the wire (4) is wound on the cylindrical plate (3) in a suitable manner by winding it sequentially up to the IO layer. Fixed with fixtures and straight racetrack type coil (
5) was produced.

Next, as shown in Fig. 2, a molding convex mold (8) ( 9) facing the same direction, and further these convex shapes (8) (9)
) is a hydraulic cylinder (1) attached to the base (1).
0) allows for movement on the base (1) at right angles to the line connecting the centers M and N of the cylindrical plates (2) and (3).

After that, actuate the hydraulic cylinder (10) to operate the convex shape (8) (
9) were moved together, and the convex portion having a predetermined radius of curvature was brought into contact with the straight portion (6) (6°) of the coil (5) and was gradually pressed. At the same time, the center distance UN of the cylindrical plates (2) and (3) is gradually decreased while taking care not to loosen the superconducting wire constituting the coil (5) or apply excessive tension. Form into an arcuate racetrack type coil (l1) with a bending angle of 60° as shown in the figure.

After that, in order to maintain this coil shape, the above base,
After fixing the inner and outer circumferential surfaces of the coil (l1) in the above shape using a convex jig and a fixing jig (not shown), the whole is inserted into a heating furnace, and the coil (ll) is heated and cured. Integrated.

After heat curing, the above-mentioned jigs, etc. have been subjected to mold release treatment, so the coil itself can be easily taken out, and the fourth
The integrated arcuate racetrack coil shown in the figure (l
1) was obtained.

In this example, a method for manufacturing an arcuate racetrack coil with a bending angle of 60° was explained, but this bending angle was 0°.
Applicable up to a range of 180°. However, if the bending angle is large (for example, 180° as shown in Figure 5)
When , the molding convex mold (8°) is placed inside the coil.
The width must be smaller than the diameter of the cylindrical plate, so it is a split type.

Furthermore, although this embodiment deals with manufacturing a planar arc-shaped racetrack coil, the method of the present invention can produce a saddle-shaped coil (12) with both ends of the coil raised as shown in FIG. Manufacturing is also possible.

〔Effect of the invention〕

As described above, according to the method of the present invention, the circumference of the wire rods constituting each layer remains unchanged before and after forming a linear racetrack coil into an arc shape, so that the wire rods do not become loose or overtensioned due to forming. A superconducting coil with excellent stability can be obtained. In addition, since the tension of each wire can be made equal, the coil as a whole has less deformation and excellent dimensional accuracy, making it easy to incorporate into iron cores and formers.Furthermore, the gap between the iron core and the like can be made smaller, allowing the wire to move during operation. is significantly reduced, and stability is further improved. Furthermore, since the number of convex molds for molding is small and the molding operation is simple, it is possible to manufacture coils at low cost and in a short period of time, which brings about remarkable industrial effects.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing a method of winding a linear racetrack type coil, Fig. 2 is a plan view showing the coil before being formed into an arc shape in an embodiment of the method of the present invention, and Fig. 3 is a diagram of the method of the present invention. FIG. 4 is a perspective view showing an arcuate racetrack coil, and FIG. 5 is an arcuate racetrack coil with a bending angle of 180°. FIG. 6 is a perspective view showing a saddle-shaped coil, FIG. 7 is a plan view showing the conventional method, and FIG. FIG. 3 is an explanatory diagram for showing that the line length remains unchanged. l- Base 2.1 Cylindrical plate 4 Superconducting wire 5 Straight racetrack coil 6, 6' Straight section plate 7 Connecting plate 8.8" Inner molded convex type, 9 .9' ~ Convex mold for molding 101 Hydraulic cylinder 111 Arc-shaped racetrack coil 12 One saddle-shaped coil 13 One-turn mold 14. 14° / one-press mold Fig. 3 Fig. 4

Claims (1)

[Claims] (1) In the method for manufacturing an arcuate racetrack coil, after winding the wire into a linear racetrack coil,
An arc-shaped convex mold having a predetermined radius of curvature is brought into contact with two parallel straight parts, respectively, and press-formed in the same direction, and at the same time, without moving the wire at both ends of the coil in the winding direction. A method for manufacturing an arcuate racetrack coil, which comprises reducing the distance between both ends of the coil while applying tension to the wire rod.