JPS623967B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a superconducting electromagnet used in superconducting magnetic levitation vehicles and the like.

In recent years, much research and development has progressed regarding magnetic levitation vehicles using superconducting electromagnets, and small, lightweight, yet powerful superconducting electromagnets have begun to be manufactured. For this reason, the ampere turns of superconducting electromagnets have increased to an extremely high level, and the structure of superconducting electromagnets has been made into a race track shape, that is, an oval structure, in order to flow an effective magnetic flux to the levitation coil on the ground side.
At the same time, in order to ensure as effective a space between the electromagnet structure and the ground coil as possible, the cross section of the superconducting electromagnet structure itself is flattened, and the resulting margin allows the ampere turns of the electromagnet to be reduced, reducing overall consumption. The idea of reducing power consumption has also arisen. If the structure of the superconducting electromagnet is made into a racetrack type with a flattened cross section, for example, 800KAT can be generated between the coil parts on opposite sides of the racetrack type coil body.
In this case, a huge repulsive force of up to 26 tons/m acts, which acts to force the racetrack-shaped coil body into a circular shape. In this way, the acting force of 26 tons/m is extremely excessive for a vehicle that desires to be lightweight, and as shown in Figure 1, the inner tank is configured in the same racetrack shape to house and hold the coil body. Even if an attempt is made to prevent the deformation by arranging the central connecting beam 2 and the end connecting beams 3A and 3B so as to particularly connect the long parallel parts of the 1, it will not be possible if electromagnetic force acts on the coil body housed inside. Although the amount is small, the inner tank 1 is deformed as shown by the dotted line. In this way, even a slight deformation of the inner tank 1 affects the superconducting coil core wire of the inner coil body, resulting in superconductor breakdown, so-called quenching. In particular, if the inner tank 1 is also made to have a flat cross-section to match the coil body, the above-mentioned deformation is likely to occur easily, making the superconducting electromagnet extremely unstable and potentially useless. As a countermeasure to this problem, it may be possible to construct the inner tank 1 from a thick plate, but this would increase the thickness of the inner tank, which has been reduced in size by making it flat, and would also damage the weight reduction that has been made with great effort. Furthermore, if the inner tank is made of a thick plate, the structure may be difficult to establish due to other aspects such as poor adhesion when fixing the inner coil body through a spacer.

The present invention was made in view of the above circumstances, and its purpose is to provide an extremely stable and high-performance superconducting electromagnet that is lightweight and effectively strengthens the inner tank without affecting the flat cross-sectional dimensions. It is to do so.

Before explaining the embodiments of the present invention, FIG.
To explain the general structure and problems of the flat cross-section superconducting electromagnet in a little more detail with reference to FIG. 3, FIG. Although not shown, it is housed and held inside an outer tank that is vacuumed and specially insulated, and inside the inner tank 1, a coil body 5 in which superconducting wire is wound and solidified and fixed by molding or the like is stored and held, and is laid downward (not shown). It is designed to face the ground side coil for levitation. The inner tank 1 has a two-part structure consisting of an inner circumferential wall 1A and an outer circumferential wall 1B, and a spacer 6 is attached to the coil main body 5, and the inner and outer circumferential walls 1A and 1B are covered to cover the outer circumference of the coil body 5, and weld beads 4A and 4B are formed. Joined by
The overall structure is a race track shape. Here, spacers 6 (third
) is in contact with the inner and outer circumferential walls 1A and 1B of the inner tank 1, and the electromagnetic force acting on the coil body 5 is transferred to the inner layer 1.
The coil main body 5 and the inner tank 1 combine to have strength. Further, the spacer 6 (not shown, but is made in two parts and assembled by welding or the like while surrounding the outer periphery of the coil main body 5) is provided with a hole 7, a groove 8, etc., and the inner tank 1
The liquid helium poured into the inner tank passes through the holes 7 and the grooves 8 and cools the coil body 5 to 4 to 5 degrees over the entire area inside the inner tank 1 to maintain the superconducting state, and the vaporized helium Gas can be vented upwards through the grooves 8 and the like.

In a superconducting electromagnet having such a configuration, since the spacers 6 are arranged at regular intervals, the section of the inner tank 1 that is in contact with the spacers 6 can maintain a cross section that is relatively close to the shape of the spacers 6;
Since the inner tank 1 has a flat cross-section in the portions not in contact with the spacer 6, the portions 1AA and 1BA of the inner and outer circumferential walls 1A and 1B with large radii of curvature tend to be easily deformed. FIG. 3 shows a racetrack-shaped inner tank 1 and a curved section of the coil body 5. The inner tank 1 almost maintains its cross-sectional shape where the spacer 6 is provided, but where the spacer 6 is not provided, the inner tank 1 maintains its cross-sectional shape. Deformation occurs as shown by the dotted line. In other words, the second
1 of the inner and outer peripheral walls 1A and 1B of the inner tank 1 shown in the figure.
Since the parts corresponding to AA and 1BA are easily deformed, when the coil body 5 is energized, a large electromagnetic force acts on the inner tank 1, and the outer circumference of the inner tank 1 is fixed at the position of the spacer 6 as shown by the dotted line in Figure 3. The wall 1B is buckled outward, and the inner peripheral wall 1A is deformed into a nearly straight polygonal shape with the spacer 6 as a node. This can generally be explained by the curved beam theory, which states that when a beam undergoes partial deformation, it cannot effectively exert its strength, but since the influence of the spacer 6 is very strong, the curved beam theory This is a very difficult problem to analyze honestly.
However, in any case, the inner and outer peripheral walls 1A and 1B of the inner tank 1
It is clear that the portions corresponding to 1AA and 1BA are extremely weak and have only a very small reinforcing effect on the coil body 5.

Here, a fourth embodiment of the superconducting electromagnet of the present invention will be described.
This will be explained using the cross section of the inner tank shown in the figure. The one shown in Fig. 4 effectively reinforces the inner tank 1, which has the same flat cross-sectional structure as shown in Fig. 2, and satisfies all the conditions necessary for a superconducting electromagnet, such as weight reduction, strengthening of the effective cross-section with limited dimensions, and secure fixation of the spacer. Consideration has been given to the functionality.

That is, the inner tank 1 of this superconducting electromagnet has liquid helium cooled to an extremely low temperature inside, and if the superconducting state is broken due to some inconvenience, the current flowing inside the coil body 5 becomes normal conductive. Heat is consumed in some coils, the entire coil is heated by that heat, almost all of the coils become normal conductive, and the heat vaporizes the cooling liquid helium. Although this vaporized helium gas is released by a safety valve, the pressure inside the inner tank inevitably increases temporarily. For this reason, due to the relationship between the expected rising pressure and the internal volume of the inner tank 1, it may be subject to legal regulations as a pressure vessel.For this reason, the thickness of the inner and outer peripheral walls 1A and 1B of the inner tank 1 is legally required to be a certain thickness. This is required.
Although it is possible to configure the inner tank 1 with this legally required minimum plate thickness without any problem, with this plate thickness, the
It is difficult to prevent deformation of portions 1AA and 1BA with large curvature radii of inner and outer peripheral walls 1A and 1B of inner tank 1 as shown in the figure. However, according to the legally required minimum inner tank plate thickness, when forming the inner tank 1 by joining the inner and outer peripheral walls 1A and 1B with weld beads 4A and 4B, the spacer 6 and the inner tank 1 are securely connected by the welding shrinkage. It is possible to fix it tightly. For this reason, as already mentioned, when the thickness of the inner tank 1 is increased, the weight increases and the adhesion between the spacer 6 and the inner tank 1 deteriorates, and the electromagnetic force induces the spacer 6 to move. There is a risk that this may affect the superconducting coil core wire of the coil body 5 and cause quenching.

Therefore, in the superconducting electromagnet of the present invention shown in FIG. 4, the inner tank 1, its inner and outer circumferential walls 1A, 1B, welding beads 4A, 4B, coil body 5, and spacer 6 are the same as those in FIG. 2 above.
Corners 1AC, 1AD, and 1BC with a small radius of curvature of the inner and outer peripheral walls 1A, 1B of the inner tank 1 are welded and assembled with a coil main body 5 having a flat cross section housed therein via a spacer 6, and are assembled to have a flat cross section. Reinforcement plates 9A, 9B and 10A, 10 are installed on each outer surface of 1BD.
B is polymerized and welded. The reinforcing plates 9A, 9B and 10A, 10B are plates having an arcuate cross section curved along the outer surfaces of the corners 1AC, 1AD and 1BC, 1BD with small curvature radii, and the reinforcing plates 9A, 9B and 10A, 10B are curved along the outer surfaces of the corners 1AC, 1AD and 1BC, 1BD with a small radius of curvature. The opposing large radius of curvature parts 1AA, 1BA are selected to have a width and wall thickness that hardly protrudes outward from the opposite sides of each other, and each end is attached to the weld bead 4A for assembling the inner tank peripheral wall on both sides. They are fixed to the outer surfaces of the inner and outer circumferential walls 1A and 1B, respectively, by weld beads 11 at positions that do not overlap with the inner and outer circumferential walls 1A and 1B.

Now, to explain the function of the inner tank structure of the superconducting electromagnet according to the present invention, since the inner and outer peripheral walls 1A and 1B of the inner tank 1 are constructed with the minimum plate thickness legally required as a pressure vessel, the weld bead 4A ,4
Welding shrinkage during welding assembly by B was achieved well,
The spacer 6 is firmly contacted and fixed to the inner surfaces of the inner and outer circumferential walls 1A and 1B of the inner tank 1, so that even when a strong electromagnetic force is transmitted to the inner tank 1, the spacer 6 does not move even slightly. Next, reinforcing plates 9A, 9B, 1
0A and 10B are corners 1AC of the flat cross section of the inner tank 1,
1AC, 1AD, and 1AD, and each end is located outward from the opposite side dimension of the inner tank 1, which is the part with the large radius of curvature, 1AA, 1BA, which is particularly trying to be small in terms of space. Since almost no pores come out, it is possible to reinforce the inner tank without changing the external dimensions of the inner tank, which is a matter of several millimeters.

Here, when the inner tank 1 having a flat cross section is subjected to a large electromagnetic force, the parts 1AA and 1BA of the inner and outer circumferential walls 1A and 1B with large radii of curvature are likely to be displaced in the vertical direction, causing a strength problem. Therefore, it is necessary to reinforce that entire part, but as mentioned above, this is impossible due to the restrictions on the external dimensions of the inner tank 1. small corners 1AC, 1AD and 1BC, 1BD
reinforcing plates 9A, 9B and 10 on each outer surface of
A and 10B are polymerized and welded, but by providing each reinforcing plate 9A, 9B, 10A, 10B, each reinforcing plate 9A, 9B, 10A, 10B
As the thickness of the plate increases in the area corresponding to the width of The bending rigidity of the inner tank peripheral wall is improved more than the increase, and abnormal vertical displacement of the portions 1AA and 1BA with large radii of curvature can be significantly prevented.

In addition, when the inner tank 1 is subjected to a bending force in the longitudinal direction due to a strong electromagnetic force with the weld beads 4A and 4B on both sides as neutral axes, even if a reinforcing plate is provided near the neutral axis and the plate thickness is increased, the bending will not be affected. It doesn't help much in improving rigidity. In other words, this is a part where reinforcement is difficult in terms of strength and rigidity, and increasing the plate thickness due to reinforcement has a big disadvantage of increasing weight. For this reason, as mentioned above, by separating the reinforcing plates 9A, 9B on the inner circumferential wall 1A side and the reinforcing plates 10A, 10B on the outer circumferential wall 1B side, there is no need to unnecessarily increase the weight. The cross section of the inner tank becomes effective in ensuring the strength of the inner tank.

Also, these reinforcing plates 9A, 9B, 10A, 10B
In addition to fillet welding of the weld beads 11, it is also possible to perform plug welding at the center of each reinforcing plate, but when configuring the inner tank 1, the weld beads 4A, 4
1AA, 1BA when B or inner tank 1 is divided vertically
Although it is possible to place welded parts in the parts, these welding beads 4A and 4B and welding bead 1 for reinforcement mounting may be used.
1 do not overlap, so there is very little risk of defects occurring during welding work, and although it is not necessarily necessary to continuously weld the weld bead 11, it increases the tightening force for fixing the inner tank 1 to the spacer 6. It can be made to act effectively.

Since the present invention is made as detailed above, the installation of the reinforcing plate itself is relatively simple, but the effect obtained by the reinforcing installation is extremely large, and is extremely important for stably continuing excitation of a large-capacity superconducting electromagnet. In addition to achieving the desired effect, it is also possible to reduce the dimensions required for a superconducting magnetically levitated vehicle by a few millimeters, and at the same time, it is possible to obtain an extremely significant effect in reducing the weight in grams. Become.

[Brief explanation of the drawing]

Figure 1 is a side view of the inner tank of a general superconducting magnetically levitated vehicle superconducting electromagnet with a racetrack-shaped inner tank and an explanatory diagram showing the deformation during energization, and Figure 2 is a superconducting electromagnet with a flat cross section. A basic cross-sectional view of the inner tank. Fig. 3 is a cross-sectional view showing the relationship between the coil body, spacer, and inner tank with respect to a race track-shaped curved part, and an explanatory diagram that also shows the deformation of the inner tank that occurs during energization and excitation. , FIG. 4 is a basic sectional view of an inner tank of a reinforced superconducting electromagnet with a flat cross section showing an embodiment of the present invention. 1... Inner tank, 1A, 1B... Inner and outer peripheral walls, 2, 3
A, 3B... Connection beam connecting opposite sides of the inner tank, 4
A, 4B...Welding bead for assembling the inner tank peripheral wall, 5...
...Coil body, 6...Spacer, 7...Hole, 8...
... Groove, 9A, 9B, 10A, 10B ... Reinforcement plate, 11 ... Welding bead for reinforcement installation, 1AA, 1
BA……The part where the cross-sectional curvature radius of the inner tank is large, 1AC,
1AD... Corner with a small cross-sectional curvature radius of the inner tank.

Claims (1)

[Claims] 1. In a superconducting electromagnet using an inner tank assembled by welding with a flat cross-section, in which a coil body with a flat cross-section that is solidified and fixed by a mold etc. is housed and held inside via a spacer, the radius of curvature of the peripheral wall of the inner tank with a flat cross-section is A reinforcing plate is provided on each of the outer surfaces of the four small corners, and these plates hardly protrude outward from the opposite sides of the mutually opposing portions of the inner tank peripheral wall with a large radius of curvature, and overlap with the weld bead for assembling the peripheral wall of the inner tank. A superconducting electromagnet characterized by being constructed by polymerization welding to the extent that it does not occur.