JPH0221026A - Rotor supporting construction - Google Patents

Abstract

PURPOSE:To stably support an axis of rotation both in its radial direction and in its thrust direction, by providing cylindrical superconducting members so disposed as to surround permanent magnets together, and repulsion members each having magnetic repulsion against each of said permanent magnets. CONSTITUTION:A first and a second permanent magnets 25, 26 are fixed on the lower end and the axial middle portion of an axis 22 of rotation, respectively. Cylindrical superconducting members 30-33 are so disposed as to surround the permanent magnets together. When each of the superconducting members 30-33 is cooled down to its critical temperature, each of said superconducting members 30-33 is put in a superconducting condition and then expresses complete diamagnetism against each of the permanent magnets 25, 26, so that the superconducting member 30 located in the bottom of its housing and the permanent magnet 25 have axial repulsion against each other, thereby urging the whole body of the axis 22 of rotation to float up. Thus, the axis of rotation can stably be supported both in its radial and thrust directions without any complex control.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a rotating body support structure configured to support a rotating body in a non-contact manner.

<Prior Art> There has been a demand for a structure that supports a rotating body in a non-contact manner, and various fields of application are being considered, such as motor spindles for scanning laser beams in laser beam printers.

Conventionally, a magnetic bearing is a typical non-contact bearing that does not use rolling elements. This is a structure in which permanent magnets or a permanent magnet and an electromagnet are arranged facing each other, and the attraction or repulsion of the magnets is utilized.

By the way, the bearing action of magnetic force is stable when using attractive force as there is a centripetal action in the direction perpendicular to the attracting direction, but it is unstable in the attracting direction, and when using repulsive force there is a repulsive force. While it is stable in the direction of , it is unstable in the direction perpendicular to the direction of repulsion. Therefore, in practice, an electromagnet is provided on the radial support side or the thrust support side, and stabilization is achieved by controlling the magnetic force of this electromagnet.

<Problems to be Solved by the Invention> As explained above, in the conventional magnetic bearing, it is necessary to control the electromagnet to achieve stability, and it is pointed out that the control is complicated.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a rotating body support structure that can support a rotating shaft in both the radial direction and the thrust direction without complicated control.

Means for Solving the Problems> In order to achieve the above objects, the present invention has the following configuration.

That is, the rotating body support structure according to the present invention includes a permanent magnet fixed to a rotating shaft, a cylindrical superconducting member arranged to surround this permanent magnet, and an end face of the permanent magnet fixed to the rotating shaft. It is characterized in that it includes a repelling member that is arranged to face each other in the axial direction and magnetically repulses the permanent magnet.

<Effect> The effects of the configuration of the present invention are as follows.

In the superconducting state, the superconducting member surrounding the permanent magnet fixed to the rotating shaft exhibits complete diamagnetic properties toward the permanent magnet due to the so-called Meissner effect, and the two repel each other, supporting the radial load of the rotating shaft. It will be done.

Further, the permanent magnet and a repelling member such as a superconducting member or a permanent magnet having the same polarity that opposes the permanent magnet in the axial direction repel in the axial direction, so that the thrust load of the rotating body is supported.

<Example> Hereinafter, an example of the present invention will be described in detail based on the drawings.

FIG. 1 shows the basic configuration of the rotating body support structure of the present invention.

In the figure, 20 is a cylindrical housing with a bottom, and this housing 20 is attached to the lower surface of the substrate 21 with its open end facing upward. A rotating shaft 22 as a support shaft for a rotating body is housed in the hollow interior of the housing 20, and the upper end of the rotating shaft 22 is inserted into a hole 23 formed in the substrate 21 and protrudes above the substrate 21. has been done. A rotary blade 24 as a rotary body to be supported is attached to the upper end of the rotary shaft 22, and the rotary shaft 22 is configured to be rotationally driven by air blown against the rotary blade 24. Further, the lower end and the axially intermediate portion of the rotating shaft 22 are provided with a first. Second permanent magnet 25.26
is fixed.

Incidentally, a circular plate-shaped superconducting member 30 is disposed on the bottom surface of the housing 20, a ring-shaped superconducting member 31 is disposed on the top surface of this superconducting member 30, and a ring-shaped superconducting member 31 is disposed on the axially intermediate portion and near the upper end of the housing 20. Part 32.3
3 are attached to each.

In this embodiment, spacers 40, 41 made of non-magnetic material are interposed between each of the superconducting members 31, 32, 33. Note that this spacer 40.41 can be eliminated, for example, the second
As shown in the figure, it is also conceivable to make the superconducting members 30 to 33 continuous molded products in the axial direction. Examples of these superconducting members include oxide high temperature superconductors, etc.
It does not matter if it is something else.

This housing 20 is immersed in a vacuum container 60 filled with liquid nitrogen 50, and the temperature of each of the superconducting members 30 to 33 inside the housing 20 is maintained below its critical temperature Tc.

In the rotating body support structure having the above configuration, superconducting members 30 to
33 has not decreased to the critical temperature Tc, the superconducting members 30 to 33 are in a normal conductive state, so the rotating shaft 2
The permanent magnets 25 and 26 fixed at position 2 have been lowered to the position shown by the dashed line, but the superconducting members 30 to 33 have reached the critical temperature Tc.
When the superconducting members 30 to 33 are cooled down to a temperature of The permanent magnets 25 repel in the axial direction and levitate the entire rotating shaft 22. On the other hand, the superconducting member 31 near the bottom of the housing and the first
The permanent magnet 25, the other superconducting members 32, 33, and the second permanent magnet 26 at the intermediate portion of the rotating shaft repel each other in the radial direction, so that the superconducting member and the permanent magnet are positioned coaxially. In this state, the second permanent magnet 26 does not face the superconducting members 32 and 33 in the radial direction, but is held in the axially intermediate position between the two conductive members.

When the rotating shaft 22 is floated and supported in this way, the relative position between the superconducting member and the permanent magnet is stabilized in both the radial direction and the thrust direction. When the rotary shaft 22 is driven to rotate, the rotary shaft 22 rotates stably in the radial direction and the thrust direction in a non-contact manner without complicated control.

By the way, it goes without saying that the rotor support structure described above can be applied to 18 different types of equipment, and can be embodied within the scope of the spirit of the present invention. Although the rotating body support structure described above is an example of a vertical axis, it is also applicable to a horizontal axis. Furthermore, in the above embodiment, the superconducting member 30 at the bottom of the housing that supports the thrust direction may be a permanent magnet with a polarity that repels the first permanent magnet 25 at the lower end of the rotating shaft.

<Effects of the Invention> As explained above, the rotating body support structure of the present invention supports the rotating shaft by utilizing the perfect diamagnetism of the superconducting member with respect to the permanent magnet, so it is possible to move the rotating shaft in the radial direction without complicated control. It can also be stably supported in the thrust direction, and the structure is simple, so manufacturing costs can be kept low. Furthermore, since the superconducting member is placed outside, it is easy to take measures to cool it.

In this way, it is possible to provide a rotating body support structure that exhibits excellent rotational performance with a simple configuration.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional front view showing one embodiment of the basic configuration of a rotating body support structure of the present invention, and FIG. 2 is a longitudinal sectional front view of a support portion according to another embodiment of the invention. 22...Rotating shaft, 25.26...Permanent magnet, 3
0-33...Superconducting member.

Claims (1)

[Claims] (1) A permanent magnet fixed to a rotating shaft; a cylindrical superconducting member arranged to surround this permanent magnet; A rotating body support structure comprising: a repulsive member that magnetically repels a magnet;