JPH0159725B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for generating strong magnetic fields.

In recent years, in order to investigate the properties of materials, research in so-called condensed matter science has been actively conducted under extreme conditions such as ultra-high temperatures, ultra-low temperatures, ultra-high pressures, ultra-vacuum, and ultra-strong magnetic fields. Various proposals have been made for means of creating extreme conditions.

By the way, as conventional strong magnetic field generating means, there are the following. In other words, there are the Quenelle method and the implosion method, which generate a strong magnetic field instantaneously, and the multilayer coil method (Osaka University method) and the MIT method (Massachusetts Institute of Technology method), which generate a relatively long pulsed strong magnetic field. ), and there is also a superconducting coil system that continuously generates a strong magnetic field.

In the quenelle method, as shown in Figure 1, a charged capacitor bank C1 closes a switch SW1, and a large current (approximately 1 million amperes) is passed through a single-turn coil L1. ) is a method of compressing liner a and, as a result, concentrating the magnetic flux inside liner a to instantaneously obtain a strong magnetic field. In this method, a strong magnetic field of about 280 T (Tesla) is generated for only about one millionth of a second. can be generated.

In the implosion method, as shown in Figure 2, switch SW2 is closed using capacitor bank C2, a current is passed through coil L2 to generate magnetic flux, and then gunpowder b is detonated to concentrate the magnetic flux and instantaneously This method can generate a strong magnetic field of about 300 T for about one millionth of a second.

Furthermore, the multilayer coil method (Osaka University method)
uses coils with unique shapes and dimensions for each layer to equalize the electromagnetic force acting on each layer.As a result, a current of several hundred thousand amperes generates a non-destructive, relatively long pulsed strong magnetic field. In this method, the pulse width
A strong magnetic field of maximum 100T can be obtained in 100μs (microseconds).

In addition, the MIT method uses a specially shaped coil to obtain a strong magnetic field of maximum value 40T with a pulse width of 100μs.Although a continuous magnetic field can be obtained with an ordinary iron-core electromagnet, , its maximum value is about several T.

Furthermore, the superconducting coil method is a method of passing a current through a superconducting coil to obtain a continuous, constant strong magnetic field, and currently obtains a strong magnetic field of about 15 T, but the theoretical upper limit is 17.2 T.

Here, a graph comparing the strong magnetic fields obtained by each of the above methods is shown in Fig. 3. In this Fig. 3, symbol A is the characteristic obtained by the Quenelle method, and B is the characteristic obtained by the implosion method. Characteristics: C shows the characteristics obtained by the multilayer coil method, D shows the characteristics obtained by the MIT method, and E shows the characteristics obtained by the superconducting coil method.

However, conventional means have the following various problems. In other words, in the Quenelle method and the implosion method, although the maximum value is quite high, the duration is extremely short, and furthermore, there is a problem that the coil or sample is destroyed every time a strong magnetic field is applied.

In addition, the multilayer coil method and the MIT method have various advantages such as relatively long pulse width and non-destructive properties, but depending on the research topic, the duration may be short and the pulse may have a certain intensity. The problem is that it is not possible to obtain a magnetic field.

Furthermore, although it is possible to obtain a continuous and constant strong magnetic field with the superconducting coil method, it requires large-scale equipment and has the problem of not being able to obtain a strong magnetic field of 17 T or higher.

The present invention aims to solve these problems by converting the kinetic energy of a high-speed rotating disk into electromagnetic energy and maintaining a constant strong magnetic field of 20 to 30 T for more than a few seconds, which has been difficult to achieve in the past. An object of the present invention is to provide a high-speed rotating disk-type strong magnetic field generating device that can generate magnetic fields at high speed.

Therefore, the high-speed rotating disk-type strong magnetic field generating device of the present invention has a first rotating disk made of two metal rotating disks disposed with their peripheral edges close to each other so as to form a first slit on the same plane. A pair of rotating disks, and two metal sheets disposed with their peripheral edges close to each other to form a second slit in a direction orthogonal to the first slit on the same level on another plane different from the above-mentioned plane. a second pair of rotating disks made of rotating disks, and a small hole formed in the axial direction of the rotating disk by the first and second slits is arranged so as to be interposed between the magnetic poles. a driving device capable of driving each rotating disk in the first and second rotating disk pair to rotate at high speed in order to generate a strong magnetic field by converging the magnetic field generated by the magnet in the small hole. It is characterized by the fact that it was established.

Hereinafter, a high-speed rotating disk-type strong magnetic field generator as an embodiment of the present invention will be explained with reference to the drawings. FIG. 4 is a schematic diagram for explaining the arrangement of the first and second rotating disk pairs; FIG. 5 is an explanatory diagram showing the overall schematic configuration with the second pair of rotating disks omitted, FIG. 6 is an enlarged view showing the magnetic pole part with the second pair of rotating disks omitted, and FIG. An enlarged view showing a part of the magnetic pole part in more detail, Figure 8 is a schematic diagram to explain its action, Figures 9 and 10 are graphs to explain its action, and Figure 11 is its principle. FIG. 12 is a schematic diagram showing an enlarged magnetic pole portion to explain the effect thereof, and FIGS. 13 a to 13 c are graphs to explain the respective effects.

As shown in FIG. 4, two metal rotating disks 1 and 2 are arranged on the same plane so that their peripheral edges 1a and 2a are brought close together to form the first slit S1. These rotating disks 1 and 2 constitute a first rotating disk pair 5.

In addition, a second slit in a direction perpendicular to the first slit S1
In order to form the slit S2, the two metal rotating disks 3 and 4 are arranged so that their peripheral edges 3a and 4a are brought close to each other on a lower plane close to the first rotating disk pair arrangement plane. These rotating disks 3 and 4 constitute a second rotating disk pair 6.

As a result, the first and second pairs of rotating disks 5 and 6 are disposed perpendicularly and close to each other, and as a result, the first and second slits S1 and S
2, small holes H are formed in the axial direction of the rotating disks 1 to 4.

As shown in FIG. 7, the peripheral edge 2a of the rotating disk 2 is made of copper as a good conductive material, but the peripheral edge 2a of the other rotating disks 1, 3, 4 is
The same applies to a and 4a.

Further, other parts of the rotating disks 1 to 4 are made of iron material having sufficient mechanical strength.

By the way, as shown in FIGS. 5 and 6, a DC electromagnet is provided so that a small hole H is interposed between the gaps of magnetic poles N and S.

Note that a coil 7b is wound around a layered iron core (magnetic core) 7a of this electromagnet 7.
A DC power supply E is connected to b via a switch SW.

Furthermore, the opposing surfaces of the magnetic poles N and S have a spherical concave shape, and a sample insertion hole 8 is provided on the magnetic pole N side.
is formed.

Further, a drive device 9 capable of driving each of the rotating disks 1 to 4 of the first and second rotating disk pairs 5 and 6 to rotate at high speed is provided, and as this drive device 9, for example, an induction motor is used. .

Note that the rotation directions of the rotating disks 1 to 4 by the drive device 9 are as shown in FIGS. 4 to 6.

With the above-described configuration, when the rotating disks 1 to 4 are rotated at high speed, the magnetic flux φ generated in the iron core 7a of the electromagnet 7
As shown in FIG. 6, it is possible to converge into a small hole H between the magnetic poles N and S and generate a strong magnetic field in this small hole H. The principle thereof will be explained below.

Now, to simplify the explanation, we will use one metal rotating disk (this disk will be designated with the symbol 1 to represent it).
The effect will be explained below.

Now, as shown in Fig. 11, suppose that there is a disk 1 rotating at high speed between the magnetic poles N and S of the electromagnet 7 having opposing semi-circular arc-shaped pole faces, and if the switch SW is turned on in this state, A DC current i flows from the DC power supply E to excite the electromagnet 7, and a magnetic flux φ is generated between the magnetic poles N and S. As a result, an eddy current flows in the rotating disc 1, and a braking force is generated.

However, in this case, the disk 1 between the magnetic poles N and S
When the peripheral velocity v (m/s) of is sufficiently high, the magnetic flux generated by the eddy current in the disk 1
The magnetic flux φ between the magnetic poles S is opposite in direction and equal in magnitude, so the magnetic flux between the magnetic poles N and S cannot go straight and penetrate the disk 1, but instead travels in a curved manner as shown in Figure 12. It passes along the outside of the edge of the disk 1.

In such a state, the peripheral velocity v of the disk 1
(m/s) continues for a sufficiently high time, and when the speed decreases due to the braking force, the magnetic flux travels straight and penetrates the disk 1, and thereafter acts simply as a braking force. In other words, if the disk 1 rotates at high speed and has a large moment of inertia, the magnetic flux between the magnetic poles N and S will continue to curve and pass outside the edge of the disk 1 for a considerable time. .

In addition, each dimension m, n (8th
(see figure) is changed appropriately, the peripheral velocity v of the disk 1 is
The amount of passing magnetic flux and braking force with respect to (m/s) are shown in FIGS. 9 and 10, respectively. From these graphs, it can be seen that the smaller the dimension n of the amount of passing magnetic flux, the more the magnetic flux can be curved at a lower speed.As for the braking force, when the dimension m is large, the braking force peaks at a relatively small speed. , suggests that it is possible to reduce the braking force by rotating the disk 1 at a speed greater than this peak.

This suggests that by setting the dimensions m and n of the magnetic poles N and S to appropriate values, it is possible to bend the magnetic flux within a small braking force range.

The above operation remains the same even when the small holes H are formed between the magnetic poles N and S in the four high-speed rotating disks 1 to 4, and as a result, as shown in FIG. 6, the operation is uniform in the iron core 7a. The magnetic flux φ distributed between the magnetic poles N and S is converged into the small hole H, and a constant strong magnetic field is generated in the small hole H.

Fig. 13 is a graph showing the progress of strong magnetic field generation by this device; Fig. 13 a shows the change in current i and magnetic flux φ in the iron core 7a after the switch SW is turned on, and Fig. 13 b shows the braking of eddy current. It shows the attenuation state of the rotational speed of the disk due to the action.

v _nio in Fig. 13b is the minimum speed required to converge the magnetic flux into the small hole H, and when the peripheral speed of the disk is lower than v _nio , the magnetic flux travels straight through the disk, and the magnetic flux The convergence power decreases rapidly.
Figure 13c shows the density characteristics of the magnetic flux converged in the small hole H, and from this graph, after the switch is turned on,
From time t ₁ when the current increases and the iron core 7a becomes saturated,
It can be seen that the strong magnetic field in the small hole H is kept at a nearly constant value until time T ₃ when the rotational speed of the disk becomes lower than v _nio .

Note that the dimensions of each member for the experimental apparatus were set as shown in FIG. That is, the diameter of the disk is
700 mm, and the copper peripheral part of the disk has a thickness of 20 mm.
mm, width 150mm.

The cross sections of the magnetic poles N and S are 50 to 50 (mm ² ), and the inner diameter of the spherical magnetic pole surface is 50 mm.

Furthermore, the minimum distance between the magnetic pole and the disk is 10 mm.

In addition, the disc rotation speed is 3600 rpm (peripheral speed is 132
m/s), and the weight of the rotating part is approximately 450 kg.

Furthermore, the strong magnetic field characteristics F obtained by the present invention
FIG. 3 shows the results for comparison with the strong magnetic field characteristics A to E obtained by various conventional means.

Note that three or more pairs of rotating disks may be provided vertically. For example, when four pairs of rotating disks are provided, the first and third pairs of rotating disks are provided in the same phase, and the second By providing the fourth pair of rotating disks in the same phase, the first and third pair of rotating disks can have a common disk rotation axis, and the second and fourth pair of rotating disks can have a common disk rotation axis. Can be shared.

Furthermore, instead of using a highly conductive material at the peripheral edge of the rotating disk, a member having good magnetic permeability may be used.

Furthermore, if there is a risk that the disc will become hot due to the generation of eddy currents, appropriate cooling means will be used.

As detailed above, according to the high speed rotating disk type strong magnetic field generator of the present invention, the following effects and advantages can be obtained.

(1) Since it is only necessary to convert the kinetic energy possessed by the high-speed rotating disk into electromagnetic energy, there is no need for large-scale power supply equipment as with conventional methods. A current on the order of a few hundred amperes is sufficient to obtain this.

(2) Since it is possible to maintain a constant strong magnetic field for a relatively long time (several seconds or more), it is possible to conduct not only physical research using instantaneous pulsed strong magnetic fields, but also engineering research, such as dissolution in strong magnetic fields. It will also be possible to study recrystallization of solids inside and friction phenomena between weakly magnetic metals.

[Brief explanation of drawings]

Figures 1 and 2 are schematic diagrams for explaining conventional strong magnetic field generation means, Figure 3 is a graph comparing the strong magnetic field characteristics obtained by various methods, and Figures 4 to 13 are graphs showing the characteristics of the strong magnetic field generated by the present invention. This figure shows a high-speed rotating disk-type strong magnetic field generator as an example of the fourth embodiment.
The figure is a schematic diagram for explaining the arrangement of the first and second pairs of rotating disks, FIG. 5 is an explanatory diagram showing the overall configuration with the second pair of rotating disks omitted, and FIG. 7 is an enlarged view showing the magnetic pole part with the second pair of rotating disks omitted, FIG. 7 is an enlarged view showing a part of the magnetic pole part in more detail, and FIG. 8 is a schematic diagram for explaining its function. , Figures 9 and 10 are graphs to explain the effect, Figure 11 is a schematic diagram to explain the principle, and Figure 12 is a schematic diagram showing the magnetic pole part enlarged to explain the effect. Figure, 1st
Figures 3a to 3c are graphs for explaining the effects, respectively. 1 to 4...Rotating disk, 1a, 2a, 3a, 4a
...Periphery of the rotating disk, 5...First rotating disk pair,
6...Second rotating disk pair, 7...Electromagnet, 7a...
Iron core, 7b...Coil, 8...Sample insertion hole, 9...
...Drive device, E...DC power supply, H...Small hall,
N, S...magnetic pole, S1...first slit, S2...
...Second slit, SW...switch.

Claims (1)

[Scope of Claims] 1. A first rotating disk pair consisting of two metal rotating disks disposed with their peripheral edges close to each other so as to form a first slit on the same plane, and a first pair of rotating metal disks arranged on the same plane so as to form a first slit; a second rotating circle consisting of two metal rotating disks disposed with their peripheral edges close together to form a second slit in a direction perpendicular to the first slit on the same level in another plane with a different angle; a pair of plates, and a magnet disposed such that a small hole formed in the axial direction of the rotating disk by the first and second slits is interposed between the magnetic poles,
A driving device capable of driving each rotating disk in the first and second rotating disk pair to rotate at high speed is provided to converge the magnetic field of the magnet in the small hole to generate a strong magnetic field. A high-speed rotating disk type strong magnetic field generator. 2. The high speed rotating disk type strong magnetic field generating device according to claim 1, wherein the peripheral edge of each rotating disk in the first and second rotating disk pair is made of a highly conductive material. 3. The high speed rotating disk type strong magnetic field generating device according to claim 1, wherein the first and second rotating disk pairs are provided close to each other. 4. The high speed rotating disk type strong magnetic field generator according to claim 1, wherein the magnetic pole surface of the magnet has a curved concave surface. 5. The high-speed rotating disk type strong magnetic field generator according to claim 1 or 4, wherein the magnet is configured as an electromagnet.