JPH0352592B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a spiral vacuum vessel for a nuclear fusion device, and is particularly suitable for a nuclear fusion device in which a vacuum vessel in which plasma is housed and held is formed in a spiral shape. The present invention relates to a method for manufacturing a spiral vacuum container.

A spiral vacuum vessel in a conventional nuclear fusion device will be explained with reference to FIGS. 1 and 2, and its manufacturing technology will be explained with reference to FIG. 3.

FIG. 1 shows a schematic configuration of a spiral torus-shaped vacuum vessel for a nuclear fusion device, where 1 is a spiral torus-shaped vacuum vessel, 2 is a center line in the large radius direction,
The vacuum container 1 revolves around the center line 2 in the large radial direction,
It is configured in a torus shape while being wound with a winding radius of r ₀ .

For example, as shown in FIG. 3, the spiral torus-shaped vacuum container 1 constructed in this manner is constructed by winding a single right circular tube 1a along an annular winding frame 3 while heating it, and As shown in the figure, the winding frame 3 is moved along the center line 2 in the large radial direction in order to make one turn in the large radial direction, and the right circular tube 1a is further bent.

The material used for this spiral torus-shaped vacuum container 1 is required to maintain vacuum and have low magnetic permeability, and stainless steel is usually used. If this material is bent along the winding frame 3 while being heated as described above, it will be difficult to bend due to its large bending rigidity and the workability will be very poor. In addition, the small diameter cross section of the vacuum container 1 is
Since a compressive force is generated at the part in contact with and a tensile force is generated at the opposite side, the center of the small diameter cross section is eccentric toward the winding frame 3 side, and its shape becomes an inertia circle. Due to these phenomena, the tube thickness t of the vacuum vessel 1 becomes non-uniform, with thick portions and thin portions. These phenomena, namely, the fact that the small-diameter cross section does not become a perfect circle and the non-uniformity of the tube thickness t, make it impossible to provide an effective spiral torus-shaped vacuum vessel 1 when maintaining plasma within the vacuum vessel 1. It means that. In addition, the winding frame 3
If the small radius r' of the vacuum container 1 is smaller than the outer radius _r1 of the vacuum container 1, the rigidity of the winding frame 3 will be smaller than that of the vacuum container 1, and machining may become impossible. There are disadvantages such as limitations on the shape of the vacuum container.

The present invention has been made in view of the above-mentioned points, and its purpose is to provide a vacuum container with a small-diameter cross-sectional shape that is a perfect circle, and to have a uniform tube thickness, so that the shape of the vacuum container that can be manufactured using the conventional technology is It is an object of the present invention to provide a method for manufacturing a spiral vacuum vessel for a nuclear fusion device that has good dimensional accuracy and eliminates the drawback of limited space.

The present invention provides an arcuate tube having a uniform thickness, a perfect circular small-diameter cross section, and a radius of curvature, angle, and cross-sectional diameter of the vacuum vessel determined from the helical specifications of the helical vacuum vessel. A predetermined number of partial vacuum containers are formed by sequentially shifting and connecting a predetermined number according to the rotation angle determined by the specifications, and a predetermined number of these partial vacuum containers are sequentially connected to form a continuous spiral and torus shape. , consists of an upper die and a lower die whose dividing plane is the outline of the vacuum vessel when viewed from the pressing direction of a spirally formed vacuum vessel, and these dividing planes are curved surfaces, and The helical vacuum container is held and pressed using a pressing mold having a spiral groove, and when the arcuate tubes are sequentially shifted and connected, the winding center is the same as that of the torus-shaped vacuum container. The intended purpose was achieved by modifying it so that it became a smooth circle in the direction of the large radius.

Hereinafter, the present invention will be explained based on embodiments shown in the drawings.

FIG. 4 shows an embodiment of the present invention. As shown in the figure, the spiral torus-shaped vacuum container of this example is
A plurality of circular arc tubes 4a, 4b, 4c, 4 having the same shape having a radius of curvature, an angle, and a cross-sectional diameter of the vacuum container determined from the spiral specification of the spiral vacuum container.
d, 4e can be expressed as the helical specifications of the vacuum vessel 1 (at rectangular coordinates X, Y, and Z in FIG. 1, the coordinate calculation formula representing the helical specifications can be expressed as follows.

X = (R + r ₀ cosω ₀ ) cosψ Y = (R + r ₀ cosω ₀ ) sinψ Z = r ₀ sinω ₀ , where R: large radius, r ₀ : winding radius, n: number of cycles, ψ: angle in the large radial direction, A predetermined number of partial vacuum vessels are sequentially connected to each other according to the rotation angle determined by ω ₀ : winding angle), and a predetermined number of these partial vacuum vessels are sequentially connected to form a continuous spiral and torus shape. will be produced in That is, as shown in FIG. 4, if the arc tube 4a is the first arc tube, the arc tube 4b connected to it is as shown in FIG.
It is connected to the arcuate tube 4a at an angle of δ, and then similarly connected to the arcuate tubes 4c, 4d, and 4e in sequence to produce one partial vacuum vessel. (The above angle δ is expressed as δ=360/n when n elbows are used between 1 pitch.) Then, by sequentially connecting a predetermined number of these partial vacuum vessels, a continuous spiral shape is formed. A spiral toroidal vacuum vessel having a torus shape is manufactured.

According to the manufacturing method of this embodiment, the problems of non-uniformity of the tube thickness t and eccentricity of the small diameter cross section of the vacuum vessel 1 in the prior art can be solved by having the tube thickness t uniform and the small diameter cross section being perfectly circular. Using a certain arc tube, and
By manufacturing it, bending is not necessary, no special force is applied, and the tube thickness t and perfect circular shape can be maintained, making it possible to solve the problem.

Moreover, FIG. 6 shows a vacuum container 6 previously formed into a spiral shape by the method described above, which is being corrected using a three-dimensional press die 7 to obtain highly accurate dimensions. In other words, the fourth
As shown in the figure, arc tubes 4a, 4b, 4c, 4
When d and 4e are sequentially shifted and connected according to the rotation angle determined by the spiral specification of the vacuum container, the winding center 2a becomes a straight line. for example,
When a spiral vacuum vessel is manufactured using a 45° arc tube, the center point of the radius of curvature of the arc tube lies on the center line of the straight line in FIG. Therefore, when this structure is closed in the large radial direction as shown in FIG. 1, that is, when it is closed 360 degrees, the center of the torus becomes a closed polygon as shown in FIG. 8.

Further, although welding is generally used as a method for connecting a plurality of arcuate tubes, thermal deformation due to welding is inevitable. Therefore, we changed the center line of the polygon to form a smooth circle in the direction of the large radius.
Alternatively, in order to correct thermal deformation during welding, it is necessary to press the arcuate tube using the three-dimensional pressing die 7 to correct the thermal deformation.

In FIG. 9, this three-dimensional press die 7 is a 3-dimensional press die 7, when the vacuum container 1 is pressed by the three-dimensional press die 7, and the pressing direction is perpendicular to the plane of the paper. The outer lines of the vacuum vessel 1 that are formed at the time are 10a and 10b, and when these outer lines 10a and 10b are viewed from the side, as shown in FIG.
This becomes the curve b. Press molds generally have a flat surface that divides the mold, but in the case of a spiral structure like this vacuum container 1, if the dividing surface is a flat surface, the vacuum container 1 and the press mold will be separated. will interfere with each other geometrically, making it impossible to press. In order to avoid this geometric interference, the ninth
Outline 10 of the vacuum container 1 shown in FIGS.
The dividing plane may be formed by a and 10b. In addition, a groove 9 of a pressing mold for directly pressing the vacuum container 1 is provided.
is constituted by a theoretical value of the outer circumferential surface of the vacuum vessel 1.

Three-dimensional press mold 7 manufactured as above
As shown in FIG. 6, when the vacuum container 6 is pressed, the upper mold and the lower mold come into close contact with each other at the dividing surface 8, and the groove 9 for modifying the vacuum container becomes a spiral shape, creating a three-dimensional shape. Suitable for use as a press mold. FIG. 11 is a schematic diagram of the lower die of the three-dimensional pressing die 7, and the dividing surface 8 formed by the outer lines 10a and 10b of the vacuum container 1 is a curved surface as shown in the figure, and the groove 9 is the boundary. The two surfaces will have different curved surfaces.

According to this embodiment, the vacuum vessel 1 can be fixed to the above-mentioned non-uniformity of the tube thickness t, eccentricity of the small diameter cross section,
It is possible to eliminate thermal deformation caused by welding,
It becomes possible to obtain a smooth spiral torus-shaped vacuum vessel closed in the large radius direction 2, and as a result,
Sufficiently withstands external forces such as electromagnetic force and vacuum force,
This has the effect of making it possible to obtain a nuclear fusion device that can generate good plasma.

According to the method of manufacturing a helical vacuum vessel for a nuclear fusion device of the present invention described above, the tube thickness is uniform, the small diameter cross section is a perfect circle, and the radius of curvature determined from the helical specifications of the helical vacuum vessel is A partial vacuum vessel is formed by connecting a predetermined number of circular arc tubes having the same shape and angle and cross-sectional diameter of the vacuum vessel by sequentially shifting them according to the rotation angle determined by the spiral specifications of the vacuum vessel, and forming a partial vacuum vessel. A predetermined number of vacuum containers are sequentially connected to form a continuous spiral and torus shape, and the outer shape of the vacuum container formed in the spiral shape when viewed from the pressing direction is the dividing plane. Consists of an upper mold and a lower mold,
These dividing surfaces are curved surfaces, and when pressed using a pressing die having a spiral groove for direct pressing that holds the spiral vacuum container, and connects the arcuate tubes by sequentially shifting them. Since the winding center has been modified to be a smooth circle in the direction of the large radius of the torus-shaped vacuum vessel, there is no deformation of the vacuum vessel during manufacturing, the small diameter cross section is perfectly circular, and the tube thickness is small. Since a uniform state is maintained, it is possible to overcome the disadvantage of the prior art in that the shape of the vacuum container that can be manufactured is limited, and to obtain a spiral vacuum container for a nuclear fusion device with good dimensional accuracy.

[Brief explanation of drawings]

Figure 1 is a plan view schematically showing a spiral vacuum vessel for a general fusion device, and Figure 2 is A-A in Figure 1.
3 is a partial perspective view showing a spiral vacuum container manufactured by a conventional manufacturing technique, and FIG. 4 is a partial perspective view showing a spiral vacuum container manufactured by a manufacturing technique according to an embodiment of the present invention. Figure 5 is a diagram for explaining the state of misalignment between adjacent circular arc tubes, Figure 6 is a perspective view showing the state in which a spiral vacuum container is pulled with a three-dimensional push mold, and Figure 7 is a diagram for explaining the state of misalignment of adjacent arcuate tubes. A diagram showing the position of the center point of the radius of curvature of an arc tube when trying to manufacture a spiral vacuum vessel using an arc tube,
FIG. 8 is a diagram showing the position of the center of the torus when the one in FIG.
The side view in the figure and FIG. 11 are perspective views showing an example of the lower mold of the three-dimensional press mold. 4...Circular tube, 5...Elbow joint surface, 6...Spiral vacuum container, 7...Three-dimensional press mold, 8...Divided surface of three-dimensional press mold, 9...Groove of three-dimensional press mold, 10a, 10
b...Outline of the spiral toroidal vacuum container.

Claims (1)

[Claims] 1 An arcuate tube of the same shape with uniform tube thickness, a perfect circular small-diameter cross section, and a radius of curvature, angle, and cross-sectional diameter of the vacuum vessel determined from the helical specifications of the helical vacuum vessel is A predetermined number of partial vacuum containers are formed by sequentially shifting and connecting a predetermined number according to the rotation angle determined by the helical specifications, and a predetermined number of partial vacuum containers are sequentially connected to form a continuous spiral and torus shape. In addition, the spirally formed vacuum container is made up of an upper mold and a lower mold whose dividing surface is the outline of the vacuum container when viewed from the pressing direction, and these dividing surfaces are curved and , the helical vacuum container is held and pressed directly using a pressing die having a spiral groove, and when the arc tubes are sequentially shifted and connected, the winding center is a torus-shaped vacuum container. 1. A method for manufacturing a spiral vacuum vessel for a nuclear fusion device, characterized in that the spiral vacuum vessel is modified to form a smooth circle in a large radius direction.