JP2972266B2 - Non-contact levitation device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention relates to a non-contact levitation device using a superconductor.

(Prior Art) Conventionally, as a floating phenomenon caused by a superconductor, those caused by the Meissner effect and the suspension effect are known. The Meissner effect floats due to the action of the superconductor to eliminate the magnetic flux of the magnet. The suspension effect is that the magnetic flux that has entered the superconductor is fixed by the pinning effect and floats at regular intervals.

(Problems to be Solved by the Invention) The levitation action by the Meissner effect is unstable because it has no binding force against external force in a direction different from the magnetic flux.
On the other hand, levitation by the suspension effect is more stable than the Meissner effect, but has a problem that it is difficult to move.

An object of the present invention is to obtain a structure that floats stably using a superconductor.

[Constitution of the Invention] (Means for Solving the Problems) In the present invention, a cylindrical superconductor made of an oxide-based superconducting material having a large critical current density and a large pinning effect is cooled to a superconducting state. Remove the external magnetic field after applying an external magnetic field strong enough to penetrate into the superconductor,
Alternatively, by applying a magnetic field to the cylindrical superconductor in the normal conducting state and cooling it to a superconducting state by removing the external magnetic field, the magnetic field may be introduced into the tubular superconductor made of an oxide-based superconducting material. The trap is made into a superconducting magnet, and the magnet is inserted into the inside to float.

(Operation) The superconducting magnet used in the present invention is manufactured in a tubular structure using an oxide-based superconducting material. Various oxide superconducting materials can be used, but the critical current density is large,
Those having a large pinning effect are desirable.
A bismuth-based superconducting material as shown in the figure is used.

In order to magnetize a cylindrical superconductor made of such a material, it is necessary to apply a magnetic field from the outside. An external magnetic field can be applied by cooling the cylindrical superconductor into a superconducting state, applying an external magnetic field strong enough to penetrate the inside of the superconductor, removing the external magnetic field, and then magnetizing the superconductor. There are two methods of trapping the magnetic field in the superconductor by removing the external magnetic field after cooling to a superconducting state by applying an external magnetic field while applying the external magnetic field.

As the external magnetic field, any of an electromagnet and a permanent magnet may be used as long as a magnetic field having a desired strength can be applied. Also,
The application of the external magnetic field may be performed from inside or outside the cylindrical body for the purpose. In order to form a superconducting magnet by applying an external magnetic field to the superconductor in this way, it is essential to use a superconducting material having a large critical current density and a strong pinning force.

Here, the cross-sectional shape of the cylindrical superconducting magnet may be a continuous shape such as a circle or a polygon. Further, it is possible to select the shape of the superconducting magnet according to the purpose, such as parallel, taper and curvature in the axial direction. However, in any of these shapes, it is necessary to have a shape and a structure that do not hinder the induced current flowing in the superconductor in a direction perpendicular to the external magnetic field when the external magnetic field is applied. Then, superconducting magnets of various shapes satisfying such conditions can be used.

FIG. 1 shows a state of a floating phenomenon in the non-contact floating structure of the present invention. The cylindrical superconductor 1 is a superconducting magnet by magnetizing means including application of an external magnetic field. This cylindrical superconductor 1
When the permanent magnet 2 is inserted inside the
Levitating and stationary without contact with the poles facing. FIG. 1 (a) shows a horizontal state, FIG. 1 (b) shows a vertical state, and FIG. As shown in this figure, the floating state is constant even when the posture of the cylindrical superconductor is changed to vertical, horizontal, and oblique positions. Also, even if an external force is applied to the levitating and stationary magnet, it returns to its original position and stands still.

The reason why the magnet inserted into the cylindrical superconductor is stationary in the axial direction is that the N / S pole of the magnet and the N / S due to the residual magnetic field of the superconductor.
This is because the poles repel the suction. Also, the stationary in the diameter direction is due to the repulsion of the force trying to prevent the intrusion of the magnetic flux coming out of the magnet due to the strong pinning force of the superconductor, so that the gap between the magnet and the wall of the superconductor is equal. Keep a distance and stand still. Conditions for stopping the magnet inside the superconductor include (1) a superconducting material having a large pinning force, and (2) the presence of a magnetic field in the superconductor.

As the cross-sectional shape of the cylindrical superconductor, various types can be used, such as those having a constant axial cross-sectional shape and those having a changed axial cross-sectional shape. The structure of the cylindrical superconductor may be integrally formed in the axial direction and the circumferential direction, or may be formed by a combination of a plurality of members if the structure does not hinder the flow of current.

In the above description, the magnetic field distribution of the cylindrical superconductor is set in the axial direction of the cylindrical body, but this is not necessarily limited to this.
It is also possible to form the magnetic field distribution in the diametric direction or in a direction inclined with respect to the axial direction and the diametric direction by changing the application direction of the external magnetic field. Furthermore, by applying a plurality of external magnetic fields, a cylindrical superconductor having a plurality of magnetic field peaks can be obtained. At this time, the polarity of the magnetic field can be freely selected. As for the floating body, a magnetized superconductor may be used instead of the permanent magnet.

(Example) Hereinafter, an example of the non-contact floating structure of the present invention will be described with reference to the drawings. A cylindrical superconductor is manufactured using an oxide superconducting material. As the oxide-based superconducting material, a material having a large critical current density and a large pinning effect is desirable. Here, a bismuth-based superconducting material produced by a manufacturing method as shown in FIG. 2 is used. Of course, other superconducting materials can be used as long as the required performance is satisfied.

FIG. 3 shows a means for causing a non-contact levitation phenomenon in the present invention. FIG. 3A shows a state in which the cylindrical superconductor 3 is immersed in liquid nitrogen 4 and an electromagnet 5 is arranged outside. Although the cylindrical superconductor 3 is in a superconducting state in the liquid nitrogen 4, in this state, it does not float but falls even if a magnet is inserted inside. Next, an electric current is applied to the electromagnet 5 to apply an axial magnetic field to the cylindrical superconductor 3 as shown in FIG. 3 (b). A magnetic field having a distribution as shown in FIG. The distribution of the residual magnetic field in the axial direction of the superconductor is strong at the center as shown in FIG. Also,
As shown in FIG. 5, the residual magnetic field in the diametrical direction has a distribution in which the wall is strongest and lower at the center. As shown in FIG. 3D, when the magnet 7 is dropped into the superconductor 3 where such a residual magnetic field exists, as shown in FIG. Surface. The position in the axial direction of the levitation corresponds to the position of the peak of the residual magnetic field shown in FIG. Therefore, by changing the position of the electromagnet 5 and changing the peak position of the magnetic field distribution, the position where the magnet stops can be changed.

(Application) Since the non-contact levitation device of the present invention can stably and non-contactly float at any position, non-contact bearings, positioning devices, various levitation transport devices, switches, support for magnetic heads, electromagnetic actuators, Antenna support device, spirit level, inkjet head, image forming, spring, lighting device support, wind direction changing device, heat drive engine, gyro, heating device support, floating head, various collision prevention devices, vibration prevention device, caster , Probing equipment for semiconductor device testing, magnetic tape guide, carriage locking device, stirring device rotated by light irradiation, temperature detection device, flow control valve, liquid coagulation device, semiconductor wafer, ball joint, gear, electromagnetic oscillation Dynamic planar scanning optical device, overcurrent cutoff device, floating mouse device, precision weighing device, satellite attitude control device, It can be applied to a wide range of fields such as displays.

[Effect of the Invention] The levitation in the present invention is levitation in a three-dimensional space, and the levitation height is large. In addition, floating and stationary at the same distance are performed in the diameter direction of the cylindrical superconductor. By adjusting the distribution of the magnetic field strength in the cylinder axis direction, there is an effect that the rest position can be changed.

[Brief description of the drawings]

FIG. 1 is an explanatory view of the floating phenomenon of the non-contact floating structure of the present invention,
FIG. 2 is a view showing a method for producing a bismuth-based superconducting material, FIG. 3 is an explanatory view showing a means for causing a non-contact levitation phenomenon in the present invention, and FIG. 4 is a shaft of a cylindrical superconductor of an embodiment of the present invention. FIG. 5 shows the distribution of the magnetic field in the diameter direction of the cylindrical superconductor. 1 ... cylindrical superconductor, 2, 7 ... permanent magnet, 3 ... cylindrical superconductor, 4 ... liquid nitrogen, 5 ... electromagnet, 6 ... cooling tank.

Claims (2)

(57) [Claims] The present invention relates to a method of cooling a cylindrical superconductor made of a superconducting material having a large pinning effect so that a superconducting state is obtained and then applying an external magnetic field penetrating into the superconductor in the axial direction of the cylinder, and then removing the external magnetic field. Or, by applying a magnetic field to the cylindrical superconductor in a normal conducting state and cooling it while applying an external magnetic field in the axial direction of the tube to remove the external magnetic field after the superconducting state is obtained, the magnetic field in the tubular superconductor is removed. A non-contact levitation apparatus characterized in that a magnetized object is levitated inside the cylindrical superconductor in which a magnetic field distribution is formed by trapping a magnetic field. 2. The cylindrical superconductor having the magnetic field distribution,
After cooling the cylindrical superconductor made of a superconducting material having a large pinning effect to make it superconductive and applying an external magnetic field penetrating into the superconductor in the axial direction of the cylinder, the external magnetic field is removed, or Applying an external magnetic field to the cylindrical superconductor in a state while applying the external magnetic field in the axial direction of the cylinder to make the superconducting state and then removing the external magnetic field to a plurality of locations of the cylindrical superconductor. The non-contact levitation apparatus according to claim 1, wherein a plurality of magnetic fields are trapped in the cylindrical superconductor to form a magnetic field distribution having peaks at a plurality of positions.