JPH07327338A - Superconducting levitation rotary system - Google Patents

Abstract

PURPOSE:To obtain a superconducting levitation rotary system comprising a permanent magnet and a superconductor arranged oppositely each other in which stabilized rotation free from shift of the shaft is ensured for a levitation rotor. CONSTITUTION:Permanent ring magnets 11, 12 are supported on a rotary disc 10 and an annular auxiliary permanent magnet 14 producing a field in the radial direction is disposed independently on the outer peripheral surface of the permanent ring magnet 12. Consequently, repelling force is generated between the annular auxiliary permanent magnet 14 and the superconductor to increase the horizontal locking power of the rotary disc 10. Since the outer peripheral repelling force effect is superposed on the magnetic levitation effect and/or the pinning effect, a large centripetal force is produced and stabilized rotary characteristics free from shift of the shaft can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-contact superconducting levitation type rotating device for use in a flywheel or a magnetic bearing device for a power storage device utilizing the superconducting magnetic levitation force of a superconductor, and to a rotating side. The present invention relates to a superconducting levitation-type rotating device that suppresses the rotational axis deviation of the above and enables an extremely smooth rotation of a turntable.

[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 oxide superconductors operating in the liquid nitrogen temperature range has made it possible to use liquid nitrogen as a cooling body, which is inexpensive and easy to handle, and high-temperature superconducting bulk having a strong superconducting levitation force. The development of the material was a major impetus for research that used the levitation force on 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.

Also in the magnetic bearing, in order to maintain stable rotation even when a large load is applied, and from the viewpoint of expansion of applications, it is required to increase their size. The following configurations are known as specific configurations of the bearing. 5 (Shikoku Electric Power Co., Inc., Shikoku Research Institute, published in June 1991, Research Bulletin No. 57 (pages 52 to 61), written by Muneaki Shibayama and Ryoichi Takahata. This is explained with reference to “Basic characteristics of superconducting magnetic bearings and study of application to large flywheel bearings”), and a pair of discs 5 in which eight disc-shaped yttrium-based superconductors 6 are annularly embedded are provided as voids. The rotating discs 3 are formed so as to face each other, and the ring-shaped permanent magnets 1 are embedded on both surfaces in the space, and are arranged concentrically with the discs with a predetermined gap from the surface of each superconductor. The ring-shaped permanent magnet 1 is usually composed of a plurality of arc-shaped Nd-Fe-B-based permanent magnets,
It is embedded in the rotary disk 3 made of a non-magnetic material and integrated with the shaft 2. A drive motor 7 is installed above the shaft 2.

[0006]

In the above device,
When a rotating force is applied to the turntable 3 incorporating the permanent magnets by the drive motor 7, the magnetic field generated by the permanent magnets and the levitation generated by the same polarity magnetic field on the opposing surface forming the shielding current flowing in the superconductor so as to cancel it. In principle, the force causes semi-permanent rotation while maintaining the non-contact state. However, in reality, due to factors such as exceeding the centripetal force due to the pinning effect peculiar to a superconductor during high-speed rotation, deviation of the center of gravity from the axis center, and non-uniformity of the magnetic field from the center, an excessive external force acts to cause levitation rotation. The body may be misaligned to stop rotation, or the levitation body may fall off.

In view of the above-mentioned problems, the present invention provides a superconducting levitation type rotating device in which a permanent magnet and a superconductor are arranged so as to face each other, and a structure in which stable rotation of the levitation rotor without axial misalignment is secured. Has an aim.

[0008]

SUMMARY OF THE INVENTION The present invention is a superconducting levitation type rotating device in which a permanent magnet body and a superconductor facing each other with a gap therebetween are rotatably arranged, and the permanent magnet body outer peripheral side. The superconducting levitation type rotating device is characterized in that an annular auxiliary permanent magnet having a magnetization direction component in the radial direction is arranged in the.

In the present invention, since the superconductor used requires strong superconducting magnetic repulsion, YBa ₂ Cu is used.
₃ O _x, an oxide high-temperature superconductor such as _{Bi 2 Sr 2 Ca 2 Cu 3} O x is used. In particular, yttrium-based and samarium-based superconductors, which can obtain strong repulsive force and stability against axis deviation, are suitable.

Conventional permanent magnet bodies used in the present invention include conventional cast magnets and ferrite magnets. In particular, a strong magnetic flux is generated on the surface facing the superconductor, which enables the miniaturization of the apparatus. High energy product Nd-Fe-
A rare earth permanent magnet such as a Pr-Fe-B magnet having excellent B-system and low-temperature characteristics is preferable. Further, the permanent magnet body may have any structure as long as a magnetic field having high uniformity can be obtained, but a structure in which a plurality of ring-shaped permanent magnets are arranged concentrically with the rotating shaft is preferable. When the outer diameter of the ring-shaped permanent magnet is small, a seamless integrated permanent magnet can also be used, and when the outer diameter is large, a plurality of bow-shaped magnets are connected as in the embodiment so that the ring-shaped permanent magnet has a required inner and outer diameter. Can be assembled into The superconductor may have any structure as long as it achieves a good magnetic levitation effect and / or pinning effect by these permanent magnets, and a plurality of disc-shaped superconductors are opposed to the permanent magnet to form an annular shape. It can be appropriately selected according to various characteristics required such as arrangement.

In the permanent magnet body and the superconductor, not only the superconductor is arranged only on one magnetic pole facing surface of the permanent magnet body, but at least one permanent magnet is arranged concentrically between a pair of superconductors. Various configurations can be adopted. The magnetizing direction of the permanent magnet body is the same as the facing direction to the superconductor in any case, but the magnetic poles (N,
It is desirable that S) be selected according to the gap size (opposing distance) between the permanent magnet body and the superconductor.

By fixing a soft metal magnetic material such as pure iron or a steel plate having good magnetic characteristics as a yoke on the surface of the permanent magnet body facing the rotary disk as a yoke, or by fixing them as a rotary disk to the permanent magnet body. Therefore, it is preferable to make the surface magnetic flux density of the permanent magnet body uniform. The metal soft magnetic material is preferably a material having a high saturation magnetic flux density, such as permendur, but may be permalloy or pure iron. The thickness of the metallic soft magnetic material is appropriately selected depending on the material described later and the dimensions of the permanent magnet. As for the method of joining the metal soft magnetic material and the permanent magnet, the metal soft magnetic material may simply be installed on the permanent magnet and fixed by the attractive force of the permanent magnet, but considering the use at high speed rotation, the adhesive It is desirable to firmly fix them by using such means as.

The rotary disk for supporting the above-mentioned permanent magnet body is not limited to the disk-shaped structure shown in the embodiment, but can support one ring-shaped magnet or a plurality of ring-shaped magnets concentrically. Any form may be used as long as it does not hinder the relative rotation with the superconductor, and the material is A
A non-magnetic material such as l or Cu is used.

In the present invention, the annular auxiliary permanent magnet is
The permanent magnet is provided around the outer peripheral end surface of the permanent magnet body or the turntable supporting the permanent magnet body, and any magnet may be used as long as it has a magnetization direction component in the radial direction with respect to the central axis. In addition to the annular one, various configurations can be selected such as a plurality of arcuate permanent magnets joined and integrated, and a plurality of annular permanent magnets having different diameters joined and integrated. Also, in terms of material, R containing Nd or Pr
When the -Fe-B system permanent magnet is used, the maximum energy product is high and a larger centripetal force can be obtained. Furthermore, as will be described later, the cross-sectional shape of the magnet is not only rectangular but also a magnetic flux generated by a right triangle or a substantially trapezoid. It is possible to face the superconductor and a greater centripetal force can be obtained. Further, the object of the present invention can be achieved even if the outer peripheral end surface is composed of a composite magnet in combination with a yoke such as pure iron, or the outer peripheral portion has a high frequency, so that it is composed of a soft ferrite magnet excellent in high frequency characteristics. It

[0015]

The operation of the superconducting levitation type rotating device according to the present invention will be described in detail with reference to the drawings. 1 and 2 show an example of a permanent magnet turntable and a superconductor turntable for a superconducting levitation type rotating device according to the present invention. 3A, 3B, 3C and 3D are longitudinal explanatory views in the diametrical direction showing another embodiment of the rotating disk according to the present invention, and the lower side of the drawing is the surface facing the superconductor.
A ring-shaped permanent magnet body 11 made of Nd-Fe-B system permanent magnets concentrically around the rotation axis on one surface of the non-magnetic rotary disk 10 and having a magnetization direction (M) in the direction opposite to the superconductor. , 12, 13 are embedded, and an annular auxiliary permanent magnet 14 composed of an Nd-Fe-B system permanent magnet having a magnetization direction component in the radial direction of the rotation axis is further provided on the outer peripheral surface of the outer ring-shaped permanent magnet body 13. It is set around. The superconductor is
As shown in FIG. 2, a plurality of superconductor blocks 15 are arranged to form two inner and outer pseudo ring-shaped superconductors 16 and 17.

The annular auxiliary permanent magnet 14 has a trapezoidal cross section and has a magnetization direction (M) perpendicular to the inclined surface on the outer peripheral surface side, and supports the ring-shaped permanent magnets 11, 12, 13. By disposing another annular permanent magnet that gives a magnetic field in the radial direction of the shaft on the outer peripheral surface side of the rotating disk 10, a repulsive force is generated between the annular auxiliary permanent magnet 14 and the superconductor,
As a result, the centripetal force in the horizontal direction of the turntable 10 is increased, and in addition to the magnetic levitation effect due to the shielding current perpendicular to the facing surface and the pinning effect parallel to the facing surface, the outer peripheral repulsive force effect is superimposed, which is large. A centripetal force can be obtained, and stable rotation characteristics without axis deviation can be obtained.

Although it is possible to make the cross section of the annular auxiliary permanent magnet 14 in FIG. 1 rectangular, as shown in FIG. 3, the annular auxiliary permanent magnet 14 has a substantially right-angled triangular cross section so that the magnetic flux generated from the inclined surface is generated. It is preferable to exert a strong centripetal repulsive force on the rotating disk 10 by acting on opposing superconductors. Further, as shown in FIG. 3A, an annular auxiliary permanent magnet 14 having a cross section of a substantially right triangle is provided on the outer peripheral surface of the rotating disk 10 and 3
The ring-shaped permanent magnet bodies 11, 12, 13 may be embedded and arranged. Further, as shown in FIGS. 3B and 3D, a plate-shaped back yoke 18 can be provided on the opposite side of the ring-shaped permanent magnet bodies 11, 12, 13 from the surface facing the superconductor. It is also possible to provide the ring-shaped back yokes 19 on the three ring-shaped permanent magnet bodies 11, 12, and 13, respectively, as shown in FIG.

[0018]

EXAMPLE An outer diameter of 99 mm and an inner diameter of 89 were added to the above-described turntable 10 shown in FIG. 1 having an outer diameter of 89 mm and a height of 10 mm.
mm, and a height of 10 mm, a ring-shaped permanent magnet made of Nd-Fe-B system permanent magnet was installed, and this was incorporated into a superconducting levitation-type rotating device using the yttrium-based superconductor having the configuration shown in FIG. It was measured. In the superconducting levitation type rotation device of FIG. 4, the rotating plate 10 of FIG. 1 is suspended horizontally on a shaft 21 of a drive motor 20 and a fixed plate 22 is arranged facing the shaft 21. 2 is arranged and is immersed in the liquid nitrogen 25 stored in the tank 24 arranged in the concave portion of the heat insulating material 23. The rotation characteristics were also measured in the same superconducting levitation type rotating device except that the annular permanent magnet according to the present invention was not provided. Regarding the rotation characteristics, in the comparative example device, the swing of the rotation of the turntable is large, but in the device using the annular permanent magnet according to the present invention,
Rotational runout was improved by about 8% in both the vertical and horizontal directions, the rotation of the turntable was stable, and high-speed rotation for a long time was possible.

[0019]

The superconducting levitation type rotating device according to the present invention has a permanent magnet body which is magnetically levitated on the superconductor or a permanent disk which supports the permanent magnet body and has a permanent repulsive force in the radial direction of the central axis. By joining the magnet,
In addition to the pinning effect in the superconducting phenomenon, an outer peripheral repulsive force effect is added, and a large centripetal force is obtained, so that stable rotation characteristics without rotation axis deviation can be obtained.

[Brief description of drawings]

FIG. 1 (A) is a partially cutaway top view showing an example of a turntable used in a superconducting levitation type rotating device according to the present invention, and FIG. 1 (B) is a longitudinal cross-section view in FIG. 1 (A).

FIG. 2 is an explanatory view showing an example of an arrangement of superconductors used in the superconducting levitation type rotating device according to the present invention.

3 (A), (B), (C) and (D) are longitudinal diametrical explanatory views showing another embodiment of the rotating disk according to the present invention.

FIG. 4 is a vertical cross-sectional explanatory view of a superconducting levitation type rotating device according to the present invention.

FIG. 5 is a partially cutaway perspective view showing an example of a superconducting levitation type rotating device.

[Explanation of symbols]

 1 Ring-shaped permanent magnet 2 Axis 3, 10 Rotating disk 4 Metal soft magnetic material 5 Disk 6 Yttrium-based superconductor 7, 20 Drive motor 11, 12, 13 Ring-shaped permanent magnet body 14 Annular auxiliary permanent magnet 15 Superconductor block 16, 17 ring-shaped superconductor 18, 19 back yoke 21 shaft 22 fixed plate 23 heat insulating material 24 tank 25 liquid nitrogen

Claims (1)

[Claims] 1. A superconducting levitation type rotating device in which a permanent magnet body and a superconductor which face each other with a gap are formed so as to be rotatable relative to each other, and a rotary disk supporting the outer peripheral portion of the permanent magnet body or the permanent magnet body. A superconducting levitation type rotating device, wherein an annular auxiliary permanent magnet having a radial magnetization direction is arranged on the outer peripheral side.