JPH048912A - Non-contact bearing using superconductor - Google Patents

Abstract

PURPOSE:To control movement of a non-contact bearing in the shaft direction by constituting a part or the whole of a shaft and a bearing by way of assembling a superconductor and a permanent magnet and making polarities of the magnetized superconductor and the permanent magnet in the same direction. CONSTITUTION:A bearing 1 of an oxide superconductor is magnetized so that it is to be in the same direction as the polarity of a permanent magnet arranged on a rotating shaft 2. Consequently, the rotating shaft 2 comes to a standstill in the center of the bearing 1, and it is possible to support it non-contactly and simplify a structure without a device to prevent movement in the axial direction.

Description

[Detailed description of the invention] [Purpose of the invention] Field of use in commercial industry) The present invention relates to a non-contact bearing using a superconductor.

(Prior Art) Several reports have been made regarding non-contact bearings that utilize the Meissner effect of superconductors. In this conventional non-contact bearing, either a permanent magnet or a superconductor is used in the shaft or the bearing part, and the permanent magnet and the superconductor are arranged facing each other. In such an arrangement, the Meissner effect on the superconductor is mainly utilized as the force for levitating the shaft.

FIG. 3 is an explanatory diagram of a conventional non-contact bearing device using the Meissner effect. The rotating shaft 11 is a superconductor, and the bearing I2
is made up of permanent magnets. Although it acts as a non-contact bearing in the direction perpendicular to the rotating shaft 11, it hardly acts against forces in the axial direction, so it is necessary to separately arrange the superconductors 15 and 14 at the end of the shaft.

FIG. 4 is an explanatory diagram of an example of a conventional non-contact bearing device using the Meissner effect, in which the rotation axis is vertical.

A permanent magnet 22, 23 is attached to the rotating shaft 21, superconductor bearings 24, 25 and a superconductor 26 are arranged to counteract the axial force.

(Problems to be Solved by the Invention) In the non-contact bearing that utilizes the Meissner effect described above, the shaft floats and rotates, but the Meissner effect does not work against forces in the axial direction. Therefore, due to the movement in the axial direction, the positions of the permanent magnet and the superconductor shift from their opposing positions,
The function as a bearing may be impaired. Therefore, the third
As shown in FIG. 4 and FIG. 4, it was necessary to arrange a combination of a permanent magnet and a superconductor at the end of the shaft to apply the Meissner effect in the axial direction as well to prevent the shaft from moving. An object of the present invention is to provide a non-contact bearing that can also control movement in the axial direction.

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above problems, in a non-contact bearing using a superconductor, a superconducting material having a large Meissner effect and a large pinning effect of the superconductor is magnetized. Taking advantage of this property, the shaft and bearing part are composed of a combination of a magnetized superconductor and a permanent magnet, and the two are placed facing each other, so that the polarity of the magnetized superconductor and the polarity of the permanent magnet are aligned in the same direction. A non-contact bearing can be achieved by adopting a similar configuration.

(Operation) The operation of the non-contact bearing device of the present invention will be explained based on FIG. 5. A cylindrical body 31 corresponding to a bearing is made of a superconductor. It is desirable that the superconducting material used here has a large critical current density and a large pinning effect. In order to magnetize a cylinder made of such a superconducting material, it is necessary to apply a magnetic field from the outside. The method of applying an external magnetic field is to cool the cylinder to a superconducting state, apply an external magnetic field strong enough to penetrate inside the superconductor, and then remove the external magnetic field to wrap the magnetic field and turn it into a magnet. Another method is to turn a superconductor into a superconductor state by cooling it while applying an external magnetic field in a normal conductor state, and then removing the external magnetic field to trap the magnetic field within the superconductor and turning it into a magnet. FIG. 5 shows the case where the former magnetization method is used.

As shown in FIG. 5(a), a coil 32 applies an external magnetic field strong enough to enter the inside of the superconductor to the cylinder 31 which is in a superconducting state in a coolant 34 in the axial direction of the cylinder 31. As shown in Figure 5(b), when the external magnetic field is removed,
The magnetic field that enters the superconducting cylinder is trapped by the strong pinning effect of the superconductor, and the superconducting cylinder becomes a magnet.

As shown in FIG. 5(C), when a permanent magnet 35 is inserted into the magnetized superconducting cylinder 31, it floats to the center of the superconducting cylinder 31 and remains stationary.

Since the superconducting cylindrical body 31 is magnetized, the cylindrical body 3
It maintains its balance and stands still at the center position, where the magnetic field is the strongest. Under such conditions, even if the permanent magnet 35 is moved in the axial direction, it has the property of returning to the center. This is caused by the Meissner effect in the direction perpendicular to the axis, and by the cylindrical body 31 made of a permanent magnet 35 and a magnetized superconductor in the axial direction.
This is thought to be due to the attraction and repulsion of the N-8 pole.

The present invention utilizes the special properties of such magnetized superconductors. In the above description, the bearing corresponds to a cylindrical body made of a superconductor, but it may also be a polygonal cylindrical body. Alternatively, the bearing may be made of a permanent magnet, and the part corresponding to the shaft, which is placed inside the cylindrical body, may be made of a magnetized superconductor.

(Example) Examples of the present invention will be described below. FIG. 1 is an explanatory diagram showing a bearing device according to an embodiment of the present invention. A cylindrical oxide superconductor is placed as the bearing 1, and a permanent magnet is placed on the rotating shaft 2. It is desirable that the superconducting material used here has a large critical current density and a large pinning effect, such as a bismuth-based superconducting material whose manufacturing method is shown in FIG. 6. Of course, other superconducting materials can also be used if they meet the required performance.

When the superconductor bearing 1 is magnetized in the same direction as the polarity of the permanent magnet placed on the rotating shaft 2, the rotating shaft 2 remains stationary at the center of the bearing 1 and operates as a non-contact bearing. FIG. 2 is a diagram showing another embodiment of the present invention in the case of a vertical rotating shaft.

It is also possible to similarly construct a non-contact bearing by using a permanent magnet in the bearing part and a magnetized superconductor in the shaft part.

[Effects of the invention] Since the non-contact bearing device of the present invention can stably hold the shaft at a specific position in space, the conventional non-contact bearing device that uses the Meissner effect is not a device that prevents movement in the axial direction. Since there is no need to provide a , the structure becomes simpler.

[Brief explanation of drawings]

FIGS. 1 and 2 are explanatory diagrams of the apparatus according to the embodiment of the present invention, and FIG.
4 and 4 are explanatory diagrams of a conventional non-contact bearing device, FIG. 5 is an explanatory diagram of the operation of the device of the present invention, and FIG. 6 is a diagram illustrating a manufacturing method of an example of the superconducting material used in the present invention. . 1.6.12...bearing, 2.5.11...rotating shaft,
3.7.33...Insulated container, 31...Cylindrical body, 32
... Coil, 4, 8, 16, 27, 34 ... Refrigerant,
22°23.35...Permanent magnet. Figure 3 Figure 4 Figure 1 Figure 2 Figure 5

Claims (1)

[Claims] (1) In a non-contact bearing in which part or all of the shaft and the bearing portion are composed of a combination of a superconductor and a permanent magnet, and the shaft and the bearing portion are arranged to face each other, the superconductor is magnetized, A non-contact bearing characterized in that the polarity of a magnetized superconductor and the polarity of a permanent magnet are aligned in the same direction.