JPS6019645B2 - Pancake-shaped coil - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pancake-shaped coil, particularly for nuclear fusion installation,
It also relates to large pancake-shaped coils used in energy storage devices and the like.

For example, a toroidal magnetic field coil used in a nuclear fusion device such as a critical plasma testing device has a nearly uniform field in the torus direction of a metal vacuum vessel that forms a plasma confinement space to stabilize the toroidal plasma. It is a coil for generating a strong magnetic field and is formed in the shape of a pancake. A plurality of these pancake-shaped coils are arranged in a torus shape at equal intervals on a vacuum container. This coil is made as thin as possible in order to attach it to the vacuum container and to increase the available space between the coils, but the main radius is approximately $m,
It is large with an inner radius of approximately 1.9h. It then generates a strong magnetic field of about 4 arcs. Since the pancake-shaped coil generates a strong magnetic field in this way, a strong electromagnetic force and a large thermal stress due to heating and cooling are generated. Therefore, the pancake-shaped coil must be able to withstand these large electromagnetic forces and thermal stresses. A conventional buncake-shaped coil made based on this viewpoint is shown in FIG. Generally, a pancake-shaped coil 1 is constructed by winding an electric conductor 2 in multiple layers in a pancake shape, inserting an interlayer insulator 3 between the layers, and bonding the layers of the electric conductor 2 with the interlayer insulator 3. There is.

By the way, as is clear from the same figure, in the conventional pancake-shaped coil, the cross section of the electrical conductor 2 from the beginning to the end of the winding is unchanged from the normal part other than the end of the winding, and the thickness of the interlayer insulator 3 is also the same. It remains unchanged until the end of the winding. Therefore, the thickness of the electrical conductor 4 and the interlayer insulator 5 at the end of the winding is the same as in the normal part. In other words, an electrical conductor or interlayer insulator of the same thickness is used as is until the end of the winding. A current-carrying terminal 6 is provided on the conductor 4 at the end of the winding. In this case, the interlayer insulator 3 is made of, for example, a composite insulating material made of polyamide paper having glass nonwoven fabric on both sides semi-cured with epoxy resin. By the way, with such a structure, the breaking stress 7 of the adhesive layer (interlayer insulator) near the end of the winding is large as shown in Figure 6, and the adhesive tends to peel off from the end of the winding. there were.

FIG. 6 is a study of the shear stress of the adhesive layer of the conventional coil shown in FIG. 4. 7 in the same figure
is the length of the coil drawn out linearly near the winding end, where 1 is the length of one turn, and x is the length measured along the final turn including the winding end. Furthermore, 0 is the average tensile stress of the conductor. The trout breaking stress at the end of this winding is 4.
It is believed that this is related to the thickness of the interlayer insulator near the winding end and the thickness of the electrical conductor, and elucidating these and reducing trout shear stress has been a major problem. The present invention has been made in view of the above points, and an object thereof is to provide a pancake-shaped coil that does not peel off by reducing the bonding stress of the adhesive layer near the end of the winding.

That is, the present invention makes the cross-sectional area of the electrical conductor at the end of the winding smaller than the cross-sectional area of the electrical conductor at the end of the winding, and the thickness of the interlayer insulator at the end of the winding is made smaller than the thickness of the interlayer insulator at the end of the winding. It is designed to be larger than that in order to achieve the above purpose.

Hereinafter, the present invention will be explained in detail based on illustrated embodiments.

FIG. 1 shows an embodiment thereof. Note that parts that are the same as those in the conventional model are given the same reference numerals, and therefore their explanations will be omitted. In this embodiment, the cross-sectional area of the electrical conductor 4 at the end of the winding is made small,
The thickness of the interlayer insulator 5 at the end of the winding is increased while the cross-sectional area is reduced. The current-carrying terminal 6 is attached to the electrical conductor 2 immediately before its cross-sectional area is reduced. Note that the interlayer insulator 5 at the end of the winding is formed to protrude longer than the electrical conductor 4 at the end of the winding, and this is to prevent discharge from the electrical conductor 4 in the shape of a winding. By doing this, the shearing stress of the trout near the fish end can be reduced. The results of the study are shown in Figure 5. As is clear from the figure, the shear stress at the end of the winding is much smaller than that of the conventional one shown in FIG. This is due to the following reasons. In Fig. 5, the second layer conductor indicated by B and the third layer conductor indicated by C each receive a tensile stress of 〇.

/E (E: Young's modulus of the conductor). On the other hand, the tensile stress is zero at the winding end, but the strain of the second layer conductor is transmitted to the winding end of the first layer conductor, indicated by A in the figure, through the insulator, and the first layer is forced to buckle. Breaking stress acts on the adhesive layer to cause distortion. By the way, this shear stress is in the second layer,
When the elongation of the third layer conductor is constant, the thicker the first layer electrical conductor subjected to forced strain, the harder it is to elongate. In other words, it takes more force to stretch it than if it were thinner. In other words, the Nada shear stress is large. Therefore, in order to reduce the shear stress, it is sufficient to reduce the thickness of the conductor by 4 mm. On the other hand, for interlayer insulators, as clarified by the experimental formula 7 = Gy/h (G: rigidity of the insulator, y: amount of strain, h: thickness of the insulator), the larger the thickness h, the more easily distorted. That is, the chick shear stress 7 is small. Therefore, in order to reduce scale shear stress, it is sufficient to increase the thickness of the insulator. From the above, the shear stress 7 near the winding end of the adhesive layer is 7=.

Fuwaniman ． ...(Represented by 1'.

In this), k = horse's trunk. ...[21 H: Average tensile stress of conductor t: Conductor thickness b: Insulator thickness G: Insulator rigidity E: Conductor Young's modulus 1: 1 Turn length x: Last turn including end of winding In the length measured along the winding end, x=1 indicates the end of the winding, and x=0 indicates the inner turn to be glued to the end of the winding.

Another embodiment of the invention is shown in FIG.

In this embodiment, the inside of the electrical conductor 4 at the end of the winding is shaved, and the thickness is made oblique so that the thickness gradually decreases toward the tip. The cross-sectional area of the conductor 2 is made smaller than that of the conductor 2, and the thickness of the interlayer insulator 5 at the end of the winding opposite to the electrical conductor 4 on the inclined side increases as the thickness of the interlayer insulator 3 at the end of the winding increases toward the tip. It is formed with a slope so that it gradually becomes larger than the thickness of . Even with such a configuration, the same operations and effects as those of the above-mentioned embodiments can be achieved. FIG. 3 shows yet another embodiment. In the embodiment shown in FIG. 3, both the inner and outer sides of the electrical conductor 4 at the end of the winding are shaved, and the thickness becomes gradually thinner toward the tip. The cross-sectional area of the electrical conductor 4 at the end of the winding is made smaller than the cross-sectional area of the electrical conductor 2 other than the end of the winding. The interlayer insulator 3 is formed with a slope so that the thickness gradually becomes larger toward the tip than the thickness of the interlayer insulator 3 other than the ends of the winding.

Even with such a configuration, the operation and effect are exactly the same as those of the above-described embodiment. According to this embodiment, the cross-sectional area of the conductor near the end of the winding is reduced and the thickness of the interlayer insulator near the end of the winding is increased. Can reduce stress, peeling of adhesive,
Unraveling can be prevented.

Further, since the current-carrying terminal is taken out immediately before the cross-sectional area of the conductor decreases, it is possible to secure a cross-sectional area of the conductor that does not hinder current flow. As described above, the present invention makes the cross-sectional area of the electrical conductor smaller than the cross-sectional area of the electrical conductor other than the end of the winding, and also makes the thickness of the interlayer insulator at the end of the winding larger than the thickness of the interlayer insulator at the end of the winding. Therefore, the trout shearing stress in the adhesive layer near the end of the winding is reduced, and a pancake-shaped coil without peeling can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of a pancake-shaped coil showing an embodiment of the present invention, Fig. 2 is a perspective view of a pancake-shaped coil showing another embodiment of the invention, and Fig. 3 is a perspective view of a pancake-shaped coil showing another embodiment of the invention. A perspective view of a pancake-shaped coil showing one embodiment, FIG. 4 is a perspective view of a conventional pancake-shaped coil, and FIG. 5 is a relationship between the shear stress of the adhesive layer of the present invention and the distance from the winding end. FIG. 6 is a characteristic diagram showing the relationship between the pear breaking stress of the conventional adhesive layer and the distance from the winding end. DESCRIPTION OF SYMBOLS 1... Pancake-shaped coil, 2... Electric conductor, 3... Interlayer insulator, 4... Electric conductor at the winding end, 5...・Insulation between the eyebrows at the end of the roll, 6...
...Electricity terminal. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6

Claims (1)

[Claims] 1. An electrical conductor wound in multiple layers in a pancake shape, an interlayer insulator inserted between the layers of the electrical conductor and bonding the layers, and a winding start and a winding of the electrical conductor. In a pancake-shaped coil equipped with a current-carrying terminal provided near the last winding end, the cross-sectional area of the electrical conductor at the winding end is smaller than the cross-sectional area of the electrical conductor other than the winding end, and the winding end A pancake-shaped coil characterized in that the thickness of the interlayer insulator is greater than the thickness of the interlayer insulator other than the end of the winding. 2. In claim 1, the current-carrying terminal is
A pancake-shaped coil, characterized in that it is provided on the electrical conductor near the winding end immediately before the cross-sectional area is reduced. 3. An electrical conductor wound in multiple layers in the shape of a pancake, an interlayer insulator inserted between the layers of the electrical conductor and bonding the layers, and an electrical conductor near the winding end at the beginning and end of the winding. In a pancake-shaped coil equipped with a current-carrying terminal, the inside of the electrical conductor at the end of the winding is formed with an inclination so that the wall thickness gradually becomes thinner toward the tip. The cross-sectional area of the electrical conductor is made smaller than the cross-sectional area of the electrical conductor other than at the end of the winding, and the thickness of the interlayer insulator at the end of the winding that faces the electrical conductor on the inclined side is made smaller as it goes toward the tip. A pancake-shaped coil characterized in that it is formed with a slope so that the thickness of the interlayer insulator becomes gradually larger than that of other interlayer insulators. 4. An electrical conductor wound in multiple layers like a pancake, an interlayer insulator inserted between the layers of the electrical conductor and bonding the layers, and an electrical conductor near the winding ends at the beginning and end of the winding. In a pancake-shaped coil equipped with a current-carrying terminal, both the inner and outer sides of the electrical conductor at the end of the winding are sloped so that the wall thickness gradually becomes thinner toward the tip. The cross-sectional area of the electrical conductor is made smaller than the cross-sectional area of the electrical conductor other than the end of the winding, and the thickness of the interlayer insulator at the end of the winding opposite to the inside of the slanted electrical conductor is decreased as the thickness of the interlayer insulator increases toward the tip. A pancake-shaped coil characterized in that it is formed with a slope so that the thickness of the interlayer insulator becomes gradually larger than that of other interlayer insulators.