JPH05109526A - Magnetic levitation apparatus - Google Patents

Abstract

PURPOSE:To reduce consumed electric energy by a suction electromagnet with a magnetic material levitated and maintained stably at a fixed position by magnetically connect upper and lower yokes via at least one permanent magnet. CONSTITUTION:An upper yoke 14 is elongated horizontally, and a lower yoke 16 magnetically connected to the upper yoke 14 with a space is arranged below this upper yoke. An electromagnet 18 is magnetically connected to the upper yoke 14 which generates a magnetic flux attracting a magnetic material 12. A magnetic pole 20 having a downward projection that is a magnetic pole is connected to the upper yoke 14 to make a magnetic flux generated by the electromagnet 18 act on the magnetic material 12. Further, a flux generator 22 is arranged below the projection to make a repulsive force act on the magnetic material 12. This design enables the magnetic material to be levitated and maintained stably at a fixed position and consumed electric energy by a suction electromagnet to be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic levitation device for maintaining a magnetic body in a state of being levitated by a magnetic attraction force.

[0002]

2. Description of the Related Art Generally, a magnetic levitation device generally includes an electromagnet for exerting a magnetic attraction force on a magnetic body, a distance sensor for detecting a distance between a magnetic pole surface of the electromagnet and the magnetic body, and an output signal of the sensor. And a control circuit for controlling an exciting current supplied to the electromagnet to generate a magnetic flux that floats the magnetic body and maintains the magnetic body in that state. In such a magnetic levitation device, the magnetic body is levitated at a predetermined height above the magnetic pole surface of the electromagnet by the magnetic flux passing through the magnetic pole surface of the electromagnet and is maintained in that state.

In this type of magnetic levitation device, in order to levitate the magnetic substance and maintain it in that state stably, the magnetic substance and the magnetic pole of the electromagnet when the magnetic substance is levitated to a predetermined height and is stable. It is desirable to have the distance between the faces as large as possible. This is because the magnetic attractive force changes in inverse proportion to the square of the distance. Therefore, if the distance between the magnetic body and the magnetic pole surface is small, even if there is a slight change in the distance, it is supplied to the electromagnet. This is because unless the exciting current is significantly and quickly corrected, the magnetic body cannot be stably maintained, and it is extremely difficult to control the exciting current.

Therefore, in the conventional magnetic levitation device, the distance between the magnetic body and the magnetic pole surface is increased by using a large electromagnet having a large magnetic pole surface. However, in a magnetic levitation device having a large flat magnetic pole surface, the magnetic flux that levitates the magnetic body tends to be biased toward the peripheral edge of the magnetic pole surface, so the magnetic flux that acts on the magnetic body becomes irregular, and as a result, the magnetic body I can't keep it stable. In particular, when trying to levitate a small magnetic body, due to the bias of the magnetic flux, the magnetic attraction site to the peripheral edge of the magnetic pole surface is not fixed, and as a result, the position where the distance sensor should be placed is not fixed. It is not possible to stably ascend and maintain the body. Further, in the conventional magnetic levitation device, since the magnetic body is merely attracted to the magnetic pole surface arranged above the magnetic body, a large amount of electric power must be supplied to the electromagnet.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides a magnetic levitation device capable of stably floating and maintaining a magnetic body at a predetermined position and reducing the amount of power consumed by an electromagnet for attraction. The purpose is to

[0006]

A magnetic levitation device according to the present invention comprises an upper yoke extending in a horizontal direction, and a lower yoke which is disposed below the upper yoke with a space therebetween and is magnetically connected to the upper yoke. , Generate a magnetic flux that attracts a magnetic material,
An electromagnet magnetically connected to the upper yoke, and a magnetic pole magnetically connected to the upper yoke for causing a magnetic flux generated by the electromagnet to act on the magnetic body, the magnetic pole having a downwardly projecting portion. And a magnetic flux generator disposed below the convex portion to cause a magnetic flux for repulsion to act on the magnetic body.

The magnetic substance is induced by the magnetic flux generated from the electromagnet so that the polarity on the upper side is opposite to that of the convex portion and the polarity on the lower side is the same as that of the convex portion. The magnetic flux generated from the electromagnet is concentrated on the convex portion, whereby the magnetic body is always attracted toward the convex portion. Therefore, according to the present invention, the magnetic body can be stably levitated and maintained at a predetermined position, and even a particularly small magnetic body can be stably levitated and maintained at a large distance from the magnetic pole surface. can do. Further, the magnetic flux generator generates a magnetic flux whose polarity on the upper side of the magnetic flux generator is the same as that on the lower side of the magnetic body, and therefore the magnetic flux generator exerts a repulsive force that pushes up the magnetic body on the magnetic body. Therefore, according to the present invention,
The power consumption of the suction electromagnet can be reduced.

The magnetic flux generator can be formed in a tubular shape by at least one permanent magnet. In this case, the permanent magnet is magnetized in the axial direction of the magnetic flux generator, and is arranged on the lower yoke so that the magnetization direction is the vertical direction. The magnetic flux generator may include an exciting coil wound in an annular shape. In this case, the exciting coil is arranged on the lower yoke such that the axial direction of the exciting coil is the vertical direction. In any of the above magnetic flux generators, the repulsive force of the surrounding portion is larger than the repulsive force of the axial portion, so that the magnetic body is stably maintained on the axial line. In particular, in the case of a magnetic body that is long in the vertical direction, its lower end is stably maintained.

At least one of the upper and lower yokes
It is preferable to magnetically connect via two permanent magnets. As a result, the power consumption of the electromagnet can be further reduced. However, the electromagnet may be formed of an iron core and an exciting coil wound around the iron core, and the upper and lower yokes may be magnetically connected via the iron core. Alternatively, both yokes may be magnetically connected by a simple magnetic body. You may connect to. An exciting coil of the electromagnet may be wound around the magnetic pole.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, a magnetic levitation device 10 is used as a device for maintaining a state in which a magnetic body 12 is levitated by a magnetic attraction force.

The magnetic levitation device 10 includes an upper yoke 14 extending in the horizontal direction, a lower yoke 16 arranged below the upper yoke 14 with a gap, and a magnetic flux which is arranged on the upper yoke 14 and attracts the magnetic body 12. Electromagnet 18 for generating
A magnetic pole 20 for causing the magnetic flux generated by the electromagnet 18 to act on the magnetic body 12, a magnetic flux generator 22 for exerting a magnetic flux for repulsion on the magnetic body 12, and a plurality of magnetically connecting the two yokes 14, 16. It includes a connector 24, a sensor 26 for detecting the strength of the magnetic field acting on the magnetic body 12, and a control circuit 28 for controlling the exciting current supplied to the electromagnet 12.

Each of the yokes 14 and 16 is made of a circular or quadrangular plate-shaped magnetic body. The electromagnet 18 has an exciting coil 30 wound around a magnetic pole 20. Magnetic pole 20
Has a circular cross section, and the upper yoke 14
Extends downward from the underside of the. In the illustrated example, the magnetic pole 20
Also acts as an iron core of the electromagnet 18.

The magnetic pole 20 has a downwardly projecting projection 32 at its lower end. The lower end surface of the convex portion 32 acts as one magnetic pole surface. In the illustrated example, the protrusion 32 has a short cylindrical shape as shown in FIG. However, as shown in FIG.
As shown in (E), it may be a short prism, a truncated cone, a truncated pyramid, or a hemispherical convex portion 34, 36, 38, or 40. In addition, as shown in FIGS. 2F to 2H, the protrusions 42, 44, or 4 formed by forming the corresponding ends of the magnetic pole 20 into a truncated cone shape, a truncated pyramid shape, or a hemispherical shape.
It may be six.

The magnetic flux generator 22 for repulsion is formed in a cylindrical shape by a cylindrical permanent magnet 48 as shown in FIG. 3 (A). However, the magnetic flux generator 22 may be formed in a cylindrical shape by a plurality of permanent magnets 50 as shown in FIG. Also, instead of using a cylindrical magnetic flux generator, as shown in FIG.
As shown in (C), a rectangular tube-shaped magnetic flux generator may be formed by at least one permanent magnet 52.

If the magnetic flux generator 22 is formed by at least one permanent magnet, the permanent magnet is
Are magnetized in the axial direction, and are arranged in the lower yoke 16 so that the magnetization direction is the vertical direction and the polarity of the upper end is the same as the polarity of the lower end of the magnetic body 12 due to the magnetic flux of the electromagnet 18. When the magnetic flux generator 22 is formed of a plurality of permanent magnets, adjacent permanent magnets may or may not be in contact with each other.

The magnetic flux generator 22 may be an electromagnet including an exciting coil wound in an annular shape, or an electromagnet including a cylindrical iron core and an exciting coil wound around the iron core. In this case, the exciting coil is arranged in the lower yoke 16 so that the axis of the magnetic flux generator 22 is in the vertical direction, and the polarity of the upper side portion is the same as the lower end polarity of the magnetic body 12 due to the magnetic flux of the electromagnet 18. Receiving an exciting current such that

Each connecting body 24 is composed of a permanent magnet magnetized in the vertical direction, and also connects both yokes 14 and 16 to each other.

In the illustrated example, the sensor 26 detects the amount of magnetic flux passing through the convex portion 32, and is arranged on the convex portion 32. As such a sensor 26, a Hall element, a magnetoresistive element, a search coil or the like can be used. Whichever type of sensor is used, the sensor can be arranged on the end surface of the convex portion 32. If a search coil is used, it may be arranged around the convex portion 32.

The control circuit 28, based on the output signal of the position setter 54 for setting the distance between the convex portion 32 and the magnetic body 12 and the sensor 26, outputs an electric signal corresponding to the amount of magnetic flux passing through the sensor 26. Based on the output signal of the comparator 58, which compares the generated detection circuit 56 with the output signals of the position setter 54 and the detection circuit 56 and outputs an electrical signal corresponding to the difference between the two signals, The power amplifier 60 is provided to adjust the exciting current supplied to the exciting coil 30 so that the distance between the body 12 and the convex portion 32 becomes a value set in the position setter 54.

The magnetic body 12 has a spherical shape in the illustrated example. However, the shape of the magnetic body 12 may be a rectangular parallelepiped shape, a pyramidal shape, a columnar shape, or the like. The magnetic body 12 is arranged between the magnetic flux generator 22 and the convex portion 32. The portion of the magnetic body 12 facing the convex portion 32 preferably has a shape in which magnetic flux is concentrated, like a convex portion similar to the convex portion 32.

In the illustrated example, the magnetic pole 20 has a cylindrical shape, but it may have another shape such as a prismatic shape or an elliptic cylindrical shape. The planar shape of the magnetic levitation device 10 can be a circle, an ellipse, a quadrangle, or the like.

Assuming that the magnetization directions of the magnetic flux generator 22 and the coupling body 24 are as shown in FIG.
An exciting current for exciting is supplied to the exciting coil 30 as shown in FIG. As a result, the upper polarity of the magnetic body 12 is opposite to that of the convex portion 32, and the lower polarity of the magnetic body 12 is the same as the upper side of the magnetic flux generator 22.

The magnetic flux generated by the exciting coil 30 is
Although it passes through the paths indicated by reference numerals 62 and 64 in FIG. 1, most of it concentrates on the convex portion 32 and attracts the magnetic body 12 toward the convex portion 32. Further, the magnetic flux generated by the magnetic flux generator 22 passes through the paths shown by reference numerals 66 and 68 in FIG.
It acts as a magnetic flux for repulsion that pushes it up.

Therefore, the magnetic body 12 floats at a position where the own weight of the magnetic body 12 is balanced with the sum of the magnetic attraction force due to the magnetic flux from the electromagnet 18 and the magnetic repulsive force due to the magnetic flux from the magnetic flux generator 22. And maintained in that state. Also,
The power consumption of the exciting coil 30 is reduced by a value corresponding to the repulsive magnetic flux of the magnetic flux generator 22.

When the distance between the magnetic body 12 and the convex portion 32 changes, the amount of magnetic flux passing through the sensor 26 changes accordingly. Therefore, the control circuit 28 directs the exciting coil 30 to correct the change in the distance. Controls the exciting current supplied.

Even when the amount of magnetic flux generated by the exciting coil 30 changes, the amount of magnetic flux passing through the sensor 26 also changes. Therefore, the control circuit 28 supplies the exciting coil 30 with an exciting magnetic field to correct the change in the amount of magnetic flux. Control the current.

According to the magnetic levitation device 10, the magnetic flux generator 2
Since 2 is cylindrical, the repulsive force of the surrounding portion is larger than the repulsive force of the axial portion of the magnetic flux generator 22. As a result, the valley of the repulsion magnetic field is formed below the magnetic body 12 by the magnetic flux 68 of the magnetic flux generator 22, and the magnetic body 12 is stably maintained on the axis of the magnetic flux generator 22, that is, in the valley of the repulsion magnetic field. To be done. Especially in the case of a magnetic material that is long in the vertical direction,
Its lower end is maintained stable.

Further, according to the magnetic levitation apparatus 10, since the permanent magnet is used as the connecting body 24, the power consumption of the exciting coil 30 of the electromagnet 18 can be further reduced. However, instead of using a permanent magnet as the connecting body 24, a connecting magnetic body may be used, or the connecting magnetic body may be used as an iron core of an electromagnet, and an exciting coil may be arranged around this. Alternatively, the connecting magnetic body may be used as an iron core of the electromagnet 18, and the exciting coil 30 of the electromagnet 18 may be arranged around the iron core.

The magnetic levitation device of the present invention can be used for an article display device for displaying a magnetic body itself, an ornament combined with a magnetic body, a decorative body, and the like. It can also be used as a device or the like for holding the magnetic body in a non-contact manner when spray coating the entire surface of the magnetic body.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a magnetic levitation device of the present invention.

FIG. 2 is a perspective view showing an example of a convex portion.

FIG. 3 is a plan view showing an embodiment of a repulsion magnetic flux generator.

[Explanation of symbols]

10 magnetic levitation device 12 magnetic body 14 upper yoke 16 lower yoke 18 electromagnet 20 magnetic pole 22 repulsive magnetic flux generator 24 coupling body 26 sensor 28 control circuit 30 exciting coil 32, 34, 36, 38, 40, 42, 44, 46 convex Part 48, 50, 52 Permanent magnet

Claims (6)

[Claims] 1. An upper yoke that extends in the horizontal direction, a lower yoke that is arranged below the upper yoke and is spaced apart from the upper yoke, and is magnetically connected to the upper yoke, and generates a magnetic flux that attracts a magnetic material. An electromagnet magnetically connected to the upper yoke, and a magnetic pole magnetically connected to the upper yoke for causing a magnetic flux generated by the electromagnet to act on the magnetic body, the magnetic pole having a downwardly projecting portion. And a magnetic levitation device including a magnetic flux generator disposed below the convex portion to cause a magnetic flux for repulsion to act on the magnetic body. 2. The magnetic flux generator is formed in a tubular shape by at least one permanent magnet, the permanent magnet is magnetized in the axial direction of the magnetic flux generator, and the permanent magnet is magnetized in the upper and lower directions. The magnetic levitation device according to claim 1, wherein the magnetic levitation device is arranged on the lower yoke so as to be oriented. 3. The magnetic flux generator according to claim 1, wherein the magnetic flux generator includes an exciting coil wound in an annular shape, and the exciting coil is arranged on the lower yoke such that an axial direction of the exciting coil is a vertical direction. Magnetic levitation device. 4. The upper and lower yokes are magnetically connected by at least one permanent magnet,
The magnetic levitation device according to claim 1, 2, or 3. 5. The electromagnet includes an iron core and an exciting coil wound around the iron core, and the upper and lower yokes are magnetically connected via the iron core.
2. The magnetic levitation device according to 2 or 3. 6. The magnetic levitation apparatus according to claim 1, wherein the electromagnet includes an exciting coil wound around the magnetic pole, and the magnetic pole also serves as an iron core of the electromagnet.