JPH08288125A - Superconducting magnetic levitation apparatus and magnetizing method of its superconductor - Google Patents

Abstract

PURPOSE: To provide the magnetizing method of a superconductor by which the superconductor can be magnetized easily and, further, a high power superconducting magnet can be obtained and to provide a superconducting magnetic levitation apparatus which can be utilized as it is as a high power superconducting magnet after the magnetization is completed. CONSTITUTION: A plurality of annular main permanent magnets 11 and 12 are coaxially provided so as to have their different poles face each other in the counter direction of a superconducting element. An annular auxiliary permanent magnet 13 is provided between the respective annular magnets and the magnet 13 is radially magnetized so as to have polarities different from those of the polarities of the counter poles of the adjacent main magnets. A new magnetic circuit is composed of the annular main and auxiliary permanent magnets and the gap permeance between the permanent magnets and the counter plane of the superconductor is elevated to increase the effective flux in the gap substantially and hence increase the magnetizing force for the superconductor substantially. Moreover, the magnetic characteristics of the superconducting magnet can be improved substantially.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a magnetic levitation device of a superconducting type and a method of magnetizing a superconductor, and more particularly, between the rings of main permanent magnets of a rotary disk composed of coaxial main composite permanent magnets. The present invention relates to a superconducting magnetic levitation apparatus in which a radial anisotropic magnet is arranged to increase a generated magnetic flux to improve a magnetic levitation force or a magnetizing force, and a method for magnetizing a superconductor thereof.

[0002]

2. Description of the Related Art Conventionally, a lot of research has been conducted on techniques utilizing the physical characteristics of superconductors. In particular, recently, a non-contact type utilizing the superconducting levitation force by the magnetic levitation effect and the pinning effect has been developed. The superconducting levitation type rotating device has been studied for use in magnetic bearing devices, large flywheels for electric power storage devices, etc., because it enables energy-free, low friction, and high-speed rotation in principle.

In particular, the discovery of an oxide superconductor capable of obtaining a superconducting phenomenon in the liquid nitrogen temperature region has made it possible to use liquid nitrogen, which is inexpensive and easy to handle, as a cooling body, and has a strong superconducting levitation force. The development of high-temperature superconducting bulk material has been a major impetus for research utilizing the levitation force for superconductors.

The electric power storage by the flywheel is one in which electric power is stored in rotational energy and is taken out and used as electric power when necessary. Larger superconducting flywheels allow more power storage, and such larger devices can be achieved by increasing the number of permanent magnets and superconductors. Further, by magnetizing the superconductor with a strong magnetic field, it is possible to achieve a magnetically stronger superconducting magnet.

[0005]

In the superconducting type magnetic levitation device, when the ambient temperature of the superconductor falls below the critical temperature, the superconducting phenomenon occurs and the superconductor is magnetized by the magnetic field of the permanent magnet to become the superconducting magnet. Repulsion or suction works between them, causing magnetic levitation. Therefore,
In the device in which the permanent magnet body on the rotating side and the superconductor on the stationary side are opposed to each other, the superconductor must be magnetized in advance in accordance with the magnetic pole arrangement of the permanent magnet body.

[0006] For example, in a magnetic levitation device comprising a fixed plate in which a plurality of disc-shaped yttrium-based superconductors are annularly arranged and a rotary plate in which a plurality of ring-shaped permanent magnets are embedded, a superconductor is formed in a required magnetic pole pattern. Considering the magnetizing method, in general coil magnetization for superconductor magnetization, it is necessary to perform complicated windings to form various magnetic poles in the superconductor arranged in an annular shape. Since it is extremely difficult to do so, it was magnetized using a permanent magnet.
Moreover, the magnetization using a permanent magnet cannot be magnetized with a strong magnetic field like a coil, and thus there is a problem that a strong magnetic levitation force and driving energy cannot be obtained in the magnetic levitation device.

In view of the problem of magnetizing a superconductor in a superconducting magnetic levitation device, the present invention is a strong superconducting magnet that can be easily magnetized with an arbitrary magnetic pole pattern in magnetizing using a permanent magnet. It is an object of the present invention to provide a method for magnetizing a superconductor in a superconducting magnetic levitation device capable of obtaining the above, and a superconducting magnetic levitation device that can be used as a powerful superconducting magnet as it is after the magnetization is completed.

[0008]

The inventor has conventionally magnetized a composite permanent magnet ring of a rotating disk by directly contacting the superconductor with a magnetic field parallel to the superconductor opposing direction, that is, the rotation axis direction. However, in this case, the magnetizing magnetic field strength of the superconductor mainly depends on the surface magnetic flux density peculiar to the permanent magnet, and it cannot be magnetized by a large magnetic force. By arranging the ring-shaped magnets coaxially so that the different magnetic poles face each other, the magnetizing force on the superconductor and the magnetic levitation characteristics can be improved.In addition to this, a ring-shaped auxiliary permanent magnet is placed between each ring-shaped magnet. , If it is magnetized in the radial direction and has a different polarity from the facing magnetic pole surface of the adjacent ring-shaped main magnet, a magnetic circuit is newly formed by the ring-shaped main and slave permanent magnets, and the gap permeance between the facing surfaces of the superconductor increases. , And effective magnetic flux is increased significantly to the gap, it can increase the magnetizing force of the superconductor also found that to increase the substantial magnetic properties of the superconducting magnet, thereby completing the present invention.

That is, the present invention comprises a stationary plate made of an annularly arranged superconductor, and a rotating plate made of a coaxially arranged composite ring-shaped main permanent magnet opposed to the fixed plate. A ring magnetized in the thickness direction and coaxially arranged with the different magnetic poles facing the superconductor, and in the radial direction between the rings of the composite ring-shaped main permanent magnet and the magnetized different magnetic poles with the peripheral end face of the adjacent main magnet. Is a superconducting magnetic levitation device, in which an auxiliary permanent magnet is provided. Further, in the present invention, in the above-mentioned configuration, the auxiliary permanent magnet also has a superconducting magnetic levitation device in which the thickness of the main permanent magnet is half or less in the thickness direction of the main permanent magnet, and the superconducting magnetic levitation device is arranged on the opposite side of the main permanent magnet. suggest.

Further, according to the present invention, in a superconducting magnetic levitation device in which a coaxially arranged composite ring-shaped permanent magnet and a superconductor are opposed to each other, the composite ring-shaped main permanent magnet is magnetized in the thickness direction to have different magnetic poles. A ring-shaped permanent magnet is arranged coaxially opposite to the superconductor, and a ring-shaped auxiliary permanent magnet magnetized in a radial direction between the adjacent main magnet peripheral end faces and a different magnetic pole is arranged between the rings of the composite ring-shaped permanent magnet. Is a method of magnetizing a superconductor in a superconducting magnetic levitation apparatus, wherein the magnetic pole pattern formed on the facing surface is brought into contact with the facing surface of the superconductor to magnetize the superconductor.

[0011]

The operation of the superconducting magnetic levitation device according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a semi-longitudinal sectional view showing a superconducting magnetic levitation device according to an embodiment of the present invention. First, the superconducting magnetic levitation device uses a permanent magnet having a large magnet thickness and a large residual magnetic flux density in order to secure its levitation force. For example, the rotating side rotary plate 10 facing the fixed plate 1 made of a superconductor is used. , If only the ring-shaped main permanent magnets 11 and 12 magnetized in the opposing direction of the superconductor are used, a large air gap exists between the ring-shaped main magnets and the magnetic leakage is large, and the magnetic energy held by the magnets is concentrated in the main opposing gap. Impossible to do.

Therefore, the magnetic levitation characteristics are improved by arranging the composite ring-shaped main permanent magnets coaxially arranged with different magnetic poles facing each other in the superconductor facing direction, but magnetic leakage to the air gap is avoided. First, it is necessary to further improve the efficiency of magnetic flux. On the other hand, if a yoke is used between the main ring-shaped permanent magnets, the weight will increase significantly and the size will increase, making it difficult to secure a floating gap as a rotary disk (flywheel).

Therefore, in the present invention, an auxiliary magnet magnetized in the radial direction is used. That is, in the superconducting magnetic levitation apparatus in FIG. 1, a fixed plate 1 constituted by annularly embedding a disc-shaped superconductor using, for example, a YBaCuO-based oxide superconductor as a superconductor on the bottom surface of a cryotank (not shown) is fixedly arranged. The composite ring-shaped permanent magnets 11 and 12 are used for the upper rotary disk 10 facing the upper rotary disk 10. The superconductor of the fixed plate 1 is composed of a pair of inner and outer ring-shaped superconductors 2 and 3, and the rotary plate 10 is arranged so that the ring-shaped permanent magnets 11 and 12 face the respective ring-shaped superconductors 2 and 3.
Is arranged, and a ring-shaped auxiliary permanent magnet 13 magnetized in the radial direction is arranged on the side opposite to the facing surface of the fixed platen 1 between the permanent magnets 11 and 12.

Ring-shaped permanent magnets 11 and 12 of the turntable 10
Is magnetized in a direction parallel to the rotation axis (M direction in the figure). In the figure, the facing surface of the ring-shaped permanent magnet 11 on the outer peripheral side is the N pole, the opposite side is the S pole, and the ring-shaped permanent magnet 12 on the inner peripheral side is The opposing surface is an S pole, and the opposite side is an N pole. The ring-shaped auxiliary permanent magnet 13 is magnetized in the radial direction of the rotating disk 10, the N pole on the outer peripheral side and the S pole on the inner peripheral side in the radial direction.

Here, in order to increase the permeance and improve the magnet efficiency of the ring-shaped auxiliary permanent magnet 13, the thickness of the main permanent magnets 11 and 12 is set to half or less in the thickness direction,
It is desirable to arrange the main permanent magnets 11 and 12 on the side opposite to the surface facing the superconductor, but it is also possible to further increase the thickness in the axial direction or stack a plurality of layers of magnets. As the material, Nd-Fe-B system or Pr-Fe- with high magnetic performance is used.
B-based magnets, or lightweight Nd-based bonded magnets and ferrite magnets are suitable. It should be noted that a yoke may be used in order to improve the magnetic characteristics although the weight is somewhat reduced.

With this structure, in addition to the magnetic energy possessed by the auxiliary permanent magnet 13, the leakage magnetic flux is reduced by forming a magnetic circuit by the main and sub magnets, and the ring-shaped permanent magnet 11 serving as the main magnet is relatively small in weight. It is possible to effectively utilize the magnetic properties of No. 12. That is, if the magnetic poles are magnetized in the radial direction and have different polarities from the opposing magnetic pole surfaces of the adjacent ring-shaped permanent magnets 11 and 12, a magnetic circuit is newly formed by the ring-shaped main and slave permanent magnets and the permeance between the superconductor opposing surfaces is increased. Is increased, the effective magnetic flux to the gap is greatly increased, and the magnetizing force to the superconductor can be increased.

When magnetized, the stationary platen 1 is cooled to a temperature below its critical temperature by a refrigerant such as liquid nitrogen filled in a cryotank and becomes a superconducting excited state, and the ring-shaped main permanent magnets 11 and 12 and the ring-shaped auxiliary magnets. By directly contacting the rotating plate 10 including the permanent magnet 13 with the superconductor of the fixed plate 1, the supply magnetic flux is concentrated and the magnetic fields having high magnetic flux density are obtained by the permanent magnets 11 and 12 as described above. Therefore, a stronger superconducting magnet can be obtained, and a superconducting magnetic levitation device that generates a stronger magnetic levitation force can be obtained.

As a characteristic temperature characteristic of the permanent magnet body,
The magnetized magnet has a small ambient temperature and a large magnetic energy in a low temperature region. Therefore, when magnetizing the above-mentioned superconductor, the magnetized temperature characteristic difference is utilized to make the ring-shaped permanent magnet of the rotating disk 11. Similarly to the superconductor, 12 and 13 are also placed in a low temperature atmosphere to be cooled, and the superconductor is magnetized by the obtained large magnetic field, so that a strong superconducting magnet can be obtained. After the magnetization is completed, only the cooling medium of the permanent magnet is removed to remove the frictional resistance of the cooling medium. Especially, if the surroundings of the magnet are placed in a vacuum state, the magnetic levitation force with less friction loss can be obtained. Driving energy will be obtained.

In the present invention, a conventional cast magnet, a ferrite magnet or the like is used as the permanent magnet body used for the magnetization and the movable body. Particularly, a strong magnetic flux is generated on the surface facing the superconductor, and the permanent magnet body is used for the apparatus. A rare earth permanent magnet such as a radial anisotropic Nd-Fe-B system having a high maximum energy product that enables downsizing is preferable, and particularly when cooled simultaneously at the time of magnetization, it has excellent low-temperature magnetic characteristics at -100 ° C or less. A radial anisotropic Pr-Fe-B magnet is optimal. The turntable that supports the permanent magnet body may have any configuration as long as it can concentrically support one ring-shaped magnet or a plurality of ring-shaped magnets and does not impede relative rotation with the superconductor. A non-magnetic material such as Al or Cu is used for.

[0020]

EXAMPLE As in FIG. 1, in a cryotank whose bottom and outer peripheral portions are covered with a heat insulating material (not shown), a fixed plate in which a disc-shaped superconductor made of YBaCuO as a superconductor is embedded in a ring is fixed. Two ring-shaped permanent magnets which are arranged and have different magnetic poles opposed to each other in a superconductor-opposing direction and which have different inner and outer diameters and have a predetermined distance between magnets; and a radial anisotropic auxiliary permanent magnet arranged between them. The rotating plate consisting of is opposed to the fixed plate. As a magnet, the outer ring-shaped main permanent magnet has an outer diameter of 99 mm, an inner diameter of 70 mm, and a height of 7 m.
m size Nd-Fe-B system magnet, inner ring-shaped main permanent magnet outer diameter 48 mm, inner diameter 20 mm, height 7 mm Nd-Fe-B system magnet, ring-shaped auxiliary permanent magnet approximately outer diameter 70 mm, Nd- with inner diameter of 48 mm and height of 2.5 mm
When the Fe-B magnet was used, the magnetic flux density was found to increase by about 30% at the position where the main gap was 2 mm, while the weight increase was 17%.

[0021]

According to the present invention, a radial anisotropic magnet is arranged between the rings of the main permanent magnets of the rotating disk which is composed of coaxially arranged composite ring-shaped main permanent magnets with different magnetic poles facing each other in the superconductor facing direction. It is characterized in that a magnetic circuit is newly formed by the master-slave permanent magnets in the shape of a circle to increase the generated magnetic flux and to improve the magnetic levitation force or the magnetizing force at the time of magnetization. It is particularly important in a levitation device to reduce the weight of a rotating disk made of permanent magnets, to properly secure a facing gap between the rotating disk and a fixed plate made of a superconductor, and to form a high magnetic field in the facing gap, thus providing a high-performance device. Obtainable.

[Brief description of drawings]

FIG. 1 is a semi-longitudinal sectional view showing a superconducting magnetic levitation device according to an embodiment of the present invention.

[Explanation of symbols]

 1 fixed plate 2,3 ring-shaped superconductor 10 rotating plate 11,12 ring-shaped main permanent magnet 13 ring-shaped auxiliary permanent magnet

Claims (3)

[Claims] 1. A stationary plate made of a superconductor arranged in an annular shape, and a rotary plate made of a coaxially arranged composite ring-shaped main permanent magnet opposed to the fixed plate, the composite ring-shaped main permanent magnet having a thickness direction. Ring-shaped auxiliary permanent magnets that are magnetized in the same direction and are coaxially arranged with their different magnetic poles facing the superconductor, and that are magnetically polarized between the rings of the composite ring-shaped main permanent magnet in the radial direction and the adjacent main magnet peripheral end face and the different magnetic poles. A superconducting magnetic levitation device, characterized in that 2. The superconducting magnetic levitation according to claim 1, wherein the auxiliary permanent magnet is arranged on the surface of the main permanent magnet opposite to the surface facing the superconductor in a thickness of half or less in the thickness direction of the main permanent magnet. apparatus. 3. A superconducting magnetic levitation device in which a composite ring-shaped permanent magnet coaxially arranged and a superconductor are opposed to each other,
The composite ring-shaped main permanent magnets are magnetized in the thickness direction and are coaxially arranged with their different magnetic poles facing the superconductor, and between the rings of the composite ring-shaped permanent magnets in the radial direction and between the adjacent main magnet peripheral end faces and different magnetic poles. Superconducting magnetic levitation characterized by arranging a magnetized ring-shaped auxiliary permanent magnet and magnetizing the superconductor by bringing the magnetic pole pattern formed on the facing surface of the ring-shaped permanent magnet into contact with the facing surface of the superconductor. Method of magnetizing a superconductor in an apparatus.