JPS6136687B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a toroidal coil in which a plurality of coil conductors are arranged in a torus shape and are divided into upper and lower parts and are fastened together at a joint in a strong magnetic field generator used in, for example, a torus-shaped nuclear fusion device. It is related to.

Generally, a torus-shaped nuclear fusion device is composed of a vacuum vessel 2, a plurality of toroidal coils 1, an air-core current transformer coil, (poloidal coil) 3, etc., as shown in FIGS. 1 and 2. The vacuum vessel 2 has a donut-like or circular cross section, and the plasma 4 is confined therein by magnetic fields in the toroidal direction, poloidal direction, and perpendicular direction. Heating of the plasma 4 is performed by generating an induced voltage in the plasma 4 by an air-core current transformer coil 3 wound around the vacuum vessel 2, and by using a current generated by the induced voltage.

As can be seen from FIGS. 1 and 2, this nuclear fusion device is assembled with a toroidal coil 1, a vacuum vessel 2, and an air-core current transformer coil 3 interlaced with each other.
5A and 5B are joint parts of the toroidal coil 1 divided into upper and lower parts.

Therefore, when manufacturing the device, as shown in FIG. It cannot be assembled unless you divide it into two parts.

The conventional toroidal coil and the toroidal coil of the present invention also have a structure in which the former toroidal coil is divided into two parts.

The junction of the two halves of a conventional toroidal coil is as shown in FIG.

The toroidal coil 1 is constructed by winding a coil conductor 6 several turns. 11 is interlayer insulation. At a junction 5A between the conductors 6a and 6b, which are divided into two parts, the two conductors 6a and 6b are collectively tightened using a tightening bolt 7 and a nut 8, thereby forming an integrated toroidal coil 1. 6c is a through hole in the thickness direction of the conductors 6a and 6b in the joint portion 5A, 9 is an insulating washer, and 10 is an insulating tube. 13
A pin is provided to prevent mutual slippage between the conductors 6a and 6b, and is provided for each turn. Note that the tightening bolt 7, insulating tube 10, insulating washer 9, and nut 8 are also provided on the joint 5B side in the same way as on the joint 5A side.
are tightened and connected.

However, since a strong electromagnetic force acts on the toroidal coil 1, the toroidal coil 1 is normally surrounded and supported by an outer frame (not shown). On the other hand, the toroidal coil 1 thermally expands due to Joule heat, but since it is restrained by the outer frame, a large compressive force is accumulated inside, and this force is applied to the frictional force of the joints 5A and 5B. When the pin shear force is overcome, the toroidal coil 1 slips at the joints 5A and 5B. This slippage occurs repeatedly in response to fluctuations in the value of the current flowing through the toroidal coil 1. When the fusion device is operated for a long period of time, this repeated slipping causes the upper and lower coils, which are divided into two parts, to seize at the contact surfaces 12 of their joints, and become restrained and unable to slide. Therefore, a large compressive force is repeatedly applied to the toroidal coil 1, leading to fatigue failure of the conductor.

Therefore, the joints 5A and 5B must have a structure that does not slip due to the frictional force and the shear strength of the pin 13 against the tensile force caused by electromagnetic force or the compressive force caused by heat.

In response to such demands, a structure as shown in FIG. 4 has been proposed. That is, the bolt 7 constituting the first coupling means has a long joint length.
In addition, the number of pins 13 serving as the second coupling means was increased to provide a structure that can sufficiently withstand electromagnetic force and thermal force.

However, with the recent progress in nuclear fusion research, the current flowing through the toroidal coil 1 has increased and the electromagnetic force acting on the toroidal coil 1 has also become stronger.

Therefore, simply increasing the number of bolts and pins as described above will result in uneven load distribution between the bolts, or the first coupling means, and the pins, or the second coupling means, which may cause fatigue failure of the toroidal coil. I'm getting old.

This invention was made in order to eliminate the above-mentioned drawbacks, and it is possible to maintain the strength of the joint by providing the same number of second coupling means on both sides of the first coupling means provided on the joint conductor. The purpose is to provide a device that can.

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 5, reference numeral 13 indicates two pins serving as second coupling means provided at both ends of the tightening bolt 7 in the longitudinal direction of the joint. This pin 13 is provided to withstand the tensile force of the conductors 6a and 6b due to the strong electromagnetic force generated in the coil and the compressive force of the conductor due to thermal force, and to increase the fatigue strength of the conductor joint. It is inserted every time.

As nuclear fusion devices become larger, such as recent nuclear fusion devices, unless the load distribution on the pins is equalized, there is an increased risk not only of the strength of the pins at uneven locations, but also of stress in the conductors. Loads include electromagnetic force and thermal force, and these loads act in opposite directions.

In this way, by providing the same number of pins 13 on both sides of the pair of bolts 7 and nuts 8, the load sharing at the weakest part 14 of the coil conductors 6a, 6b against forces in opposite directions is minimized. You can.

The optimality of providing the same number of pins 13 on both sides of the bolt 7 will be explained with reference to the schematic diagrams shown in FIGS. 6 to 9.

Note that FIGS. 6 to 9 correspond to the coil 1 in FIG. 5 when the bolt 7 and nut 8 are not attached when viewed from the direction of arrow A, and FIGS.
In each figure, a indicates a tensile force, and b indicates a compressive force.

Reference numeral 14 indicates the tightening bolt portion of the joint conductor, and this portion is usually the weakest portion where the conductor stress is maximum.

Figure 6 shows the case where the number of pins is one, and as for the force applied to the weakest part 14, as is clear from the figure, the magnitude of both the tensile force P ₁ and the compressive force P ₂ is P. .

FIG. 7 shows a case where the number of pins is two, and the force applied to the weakest part 14 is as shown in the figure, the tensile force is P ₁ ,
Both compressive forces _P2 are P/2. In the case shown in FIG. 7, the pins 13 are provided at substantially equal distances from both ends of the through hole 6c.

FIG. 8 shows a case where there are three pins, and the forces acting on the weakest part 14 are both 2P/3, tensile force P ₁ and compressive force P ₂ as shown.

FIG. 9 shows a case where the number of pins is four, and in this case, the force applied to the weakest part 14 is both tensile force P ₁ and compressive force P ₂ of 3P/ It is 4.

In this way, it is understood that when the number of pins is two, the force applied to the weakest part 14 is the smallest and optimal.

In the above embodiment, an example of a toroidal coil joint of a nuclear fusion device has been described, but the same effects as in the above embodiment can be achieved in other coils in which tensile force and compressive force act in opposite directions.

Further, in the embodiment, one pin 13 is provided on each side of the bolt 7, but the same number of pins 13 are provided on both sides of the bolt 7.
may be provided.

As described above, according to the present invention, the same number of second coupling means of the joint part are provided on both sides of the first coupling means, so that the tensile and compressive load applied to the second coupling means and the joint conductor is reduced. It is possible to share the load equally, prevent seizure of joints and fatigue, and provide a safe device.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a conventional nuclear fusion device, Figure 2 is a plan view of the one shown in Figure 1, Figures 3 and 4 are cross-sectional views showing conventional joints, and Figure 5 is the invention. 6 to 9 are schematic diagrams for explaining the effects of the present invention. In the figure, 1 is a toroidal coil, 5a is a joint, 6a and 6b are coil conductors, 6c is a through hole,
7 is a tightening bolt, 8 is a nut, 13 is a pin, 14
indicates the weakest part. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Scope of Claims] 1. Coil conductors that form a pair, a bolt that passes through a joint provided on these coil conductors, and a nut that is screwed onto the bolt, which presses and tightens both coil conductors at the joint. The first coupling means includes a second coupling means for suppressing mutual slippage in the longitudinal direction of the two coil conductors by means of a pin implanted in the joint surface substantially perpendicular to the contact surface, A toroidal coil characterized in that the same number of coupling means are provided on both sides of the first coupling means in the longitudinal direction. 2. The toroidal coil according to claim 1, wherein the second coupling means is provided equidistantly from the position of the first coupling means.