JP2777727B2 - Superconducting magnetic bearing device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a superconducting magnetic bearing device that supports a rotating shaft in a thrust direction and a radial direction using a force generated on a magnet of a superconducting material.

<Conventional technology> A conventional bearing device of this type is capable of stable high-speed rotation due to the Meissner effect of a superconducting material. For example, a measuring instrument (for example, a gyroscope) that performs various measurements while rotating.
It is promising to be used in disk drives and disk drives.

For example, when the rotating shaft is supported in the radial direction and the thrust direction in a non-contact manner, a magnet such as a permanent magnet or an electromagnet is attached to the periphery and the end of the rotating shaft, respectively, and a fixing member at a position facing each magnet is provided. Each of the superconducting materials is attached, and further, temperature maintaining means for maintaining the superconducting material at a predetermined critical temperature Tc or less indicating a superconducting state (for example,
(Using heat conduction) are provided near each superconducting material.

As described above, in order to facilitate the temperature control of the superconducting material by the temperature maintaining means, conventionally, the superconducting material is fixedly arranged.

<Problem to be Solved by the Invention> By the way, in the above configuration, when the rotating shaft is stopped, since the magnetism attached to the rotating shaft is affected by the geomagnetism, the magnet and the rotating shaft are always fixed at predetermined positions. It is stopped at a fixed position. The influence of the geomagnetism on the magnet becomes a rotational resistance when rotating the rotating shaft, and the magnet tends to be unstable particularly when the rotating shaft is driven at a low speed.

Therefore, it is sufficient to attach the magnet to the fixed member and attach the superconducting material to the rotating shaft.In this case, however, it is difficult to arrange and configure temperature maintaining means for keeping the temperature of the superconducting material below the critical temperature. Has not been reached.

The rotation of the rotating shaft is detected by detecting a mark formed on the rotating shaft with an optical tachometer, but when a superconducting material that needs to be cooled to a low temperature is used, the superconducting material is used. Due to the temperature difference between the periphery and the periphery of the rotating shaft where the mark is formed, frost and water droplets are attached to the rotating shaft, and the weight balance of the rotating shaft is disturbed, or the mark on the rotating shaft is hidden and rotation detection can not be performed. Inconvenience also occurs.

The present invention has been made in view of such circumstances,
It is an object of the present invention to devise means for maintaining the superconducting material at a critical temperature or lower so that the rotating shaft can be driven stably at a low rotation speed, and that problems associated with rotation detection can be solved.

<Means for Solving the Problems> In order to achieve such an object, the present invention provides a superconducting magnetic bearing that supports a rotating shaft in a thrust direction and a radial direction using a force generated on a magnet of a superconducting material. The device has the following configuration.

A superconducting magnetic bearing device according to the present invention includes: a superconducting material for thrust support and a radial support provided on a rotating shaft; a magnet fixed and arranged to face each of the superconducting materials; and a chamber surrounding the rotating shaft. And gas supply means for supplying a temperature maintaining gas for maintaining the superconducting material at a critical temperature or lower into the chamber, and the rotating shaft has a temperature maintaining It is characterized in that a turbine unit for receiving the service gas and rotating the rotary shaft is provided.

<Operation> According to the above configuration, since the superconducting material is kept at a critical temperature or lower in the chamber, the superconducting material exhibits a Meissner effect in which the superconducting material repels a magnet disposed opposite to the superconducting material. It is levitated and supported in the state.

Therefore, since the magnet is fixed, the influence of geomagnetism on the magnet can be ignored. In addition, since the superconducting material attached to the rotating shaft is kept at a critical temperature or lower in the chamber by the temperature maintaining gas, the temperature control of the superconducting material is simplified.

Further, since the predetermined temperature maintaining gas supplied into the chamber is used as a rotation driving source of the rotating shaft, the configuration of the temperature control of the chamber and the driving control of the rotating shaft are further simplified.

Further, for example, if the rotation of the rotation shaft is detected in the chamber, the occurrence of inconvenience caused by frost, water droplets, and the like as in the related art can be avoided.

<Example> Hereinafter, an example of the present invention will be described in detail with reference to the drawings. 1 and 2 show a basic configuration of the present invention.

As shown in the figure, the superconducting magnetic bearing device of this embodiment
A rotating shaft 1 made of a non-magnetic material, disk-shaped superconducting materials A and B for thrust support attached to both ends of the rotating shaft 1, and a radial attached to a peripheral portion at a predetermined position near both ends of the rotating shaft 1. Ring-shaped superconducting members C and D for support, a chamber 2 surrounding such a rotating shaft 1, disk-shaped superconducting members A and B for thrust support outside the chamber 2 and a ring-shaped member for radial support A plurality of electromagnets 3 fixedly arranged at positions facing each of the superconducting materials C and D, and a temperature maintaining gas for keeping the superconducting materials A to D below the critical temperature are supplied into the chamber 2. It comprises a gas supply means 4 and an optical tachometer 5 for detecting the number of revolutions of the rotating shaft 1.

 These components will be specifically described.

Each of the superconducting materials A to D is made of, for example, an oxide high-temperature superconducting material (YBCO) having a relatively high critical temperature Tc indicating a superconducting state.
(Material). Of course, it may be appropriately formed of another material.

The lower portion of the chamber 2 is formed in a substantially triangular cross section, and a plurality of electromagnets 3 are arranged so as to oppose left and right inclined walls 2A and 2B via a predetermined gap. Each of the electromagnets 3 faces each of the superconducting materials A to D provided on the rotating shaft 1 with the inclined walls 2A and 2B interposed therebetween.

The gas supply unit 4 sends out a temperature maintaining gas such as a helium gas cooled with liquid nitrogen, for example.
It is configured to supply the gas into the chamber 2 through a plurality of gas introduction pipes 7 each provided with an open / close valve 6 and to collect the gas through a gas discharge pipe 8. At least one of the gas introduction pipes 7 is arranged to inject a temperature maintaining gas toward a turbine unit 9 provided at a central position of the rotating shaft 1. The rotary shaft 1 is driven to rotate in accordance with the injection amount of the rotation.

The optical tachometer 5 detects the number of rotations of the mark 1A formed on the peripheral surface near the turbine section 9 on the rotating shaft 1, and
The number of rotations of the rotating shaft 1 is measured. The optical tachometer 5 is mounted on the upper wall of the chamber 2 and its sensor part faces the mark 1A.
It is projected into.

In the present embodiment, the chamber 2 and the electromagnet 3 are surrounded by the case 10, and a dehydrating gas is introduced into the case 10, or the inside of the case 10 is evacuated to a vacuum state. Frost and water droplets generated on the outer wall of the chamber 2 due to the temperature difference between the inside and the outside of the chamber 2 are removed. Note that the case 10
The above-mentioned electromagnets 3 are fixed via the respective 11.

 Next, the operation will be described.

First, the cooled helium gas is supplied from the gas supply unit 4 into the chamber 2 and the current supplied to each electromagnet 3 is controlled. The helium gas introduced into the chamber 2 directly cools the superconducting materials A to D and also cools the rotating shaft 1 so that the superconducting materials A to D are indirectly cooled by the cooling heat from the rotating shaft 1. Is cooled, and each of the superconducting materials A to D is kept almost stably below the critical temperature Tc to be in a superconducting state.

Therefore, each of the superconducting materials A to D repels the magnetic field generated from each of the electromagnets 3 by the Meissner effect, so that the rotating shaft 1 is stably levitated and supported in the thrust direction and the radial direction according to the repulsive force. Will be. Incidentally, the repulsive force between the superconducting materials A and B for supporting the thrust and the corresponding electromagnet 3 and the repulsive force between the superconducting materials C and D for supporting the radial and the corresponding electromagnet 3 are shown in FIG. Although not shown, it is desirable to control each separately by a control circuit.

On the other hand, since the helium gas introduced from one of the gas introduction pipes 7 is injected toward the turbine section 9 of the rotating shaft 1, the helium gas is injected based on the injection amount. Is driven to rotate. This rotating shaft 1
Can be appropriately controlled while being detected by the optical tachometer 5.

Thus, even if the superconducting materials A to D are arranged on the rotation side,
With the simple configuration as described above, superconducting materials A to D can be kept at a critical temperature or lower. For this reason, the electromagnet 3 can be arranged on the fixed side, and the influence of the geomagnetism on the electromagnet 3 can be eliminated. As a result, the rotating shaft 1 can be stably driven even at low speed rotation.

In addition, the temperature maintaining gas introduced into the chamber 2 for keeping the superconducting materials A to D below the critical temperature is supplied to the rotating shaft 1.
, The cooling of the superconducting materials A to D and the driving of the rotating shaft 1 are performed in a less wasteful manner than in the case where the rotating shaft 1 is driven by different means, and the entire structure is simplified. In addition, when the driving means is provided separately, since a motor generally used as the driving means has a portion that generates heat,
A structure for thermally insulating the driving means and the temperature maintaining gas flow path is required. Otherwise, the heat generated by the driving means raises the temperature of the temperature maintaining gas, and the superconducting materials A to D
It is difficult to maintain the superconducting state. On the other hand, in the present embodiment, there is no need to separately provide a driving means for the rotating shaft 1, so that it is not necessary to provide the above-described thermal cutoff structure, and the configuration can be further simplified. However, those separated from each other are also included in the present invention.

Further, since the rotation of the rotating shaft is detected in the chamber 2, the inconvenience due to frost, water droplets, and the like as in the prior art can be avoided, and accurate rotation detection can be performed.

By the way, it is needless to say that the superconducting magnetic bearing device can be applied to various devices and can be embodied without departing from the gist of the present invention. Further, the configuration of the superconducting magnetic bearing device can be implemented in other forms. For example, a structure in which the axis of rotation is a horizontal axis and the axis of rotation is a vertical axis, a case
There can be various structures such as a structure for omitting.

Further, in the superconducting magnetic bearing device having the above-described configuration, when the rotating shaft 1 is not levitated and supported, the rotating support 1 and the rotating superconducting materials C and D do not directly contact the bottom surface of the chamber 2. Alternatively, a means for receiving the rotating shaft 1 can be provided in one of the chambers 2.
In the embodiment, the electromagnet 3 facing the radially supporting superconducting materials C and D is described as being provided only below the chamber 2. However, an electromagnet may be provided separately above the chamber 2. Good.

<Effects of the Invention> As described above, according to the present invention, the magnet is fixed and the influence of geomagnetism on the magnet is ignored, so that the rotating shaft can be driven stably even at low speed rotation. Become. Moreover, regarding the means for keeping the superconducting material attached to the rotating shaft below the critical temperature, the superconducting material and the rotating shaft are housed inside the chamber to which the temperature maintaining gas is supplied, and the temperature is controlled. Therefore, the configuration for temperature control is simple.

In addition, since the temperature maintaining gas supplied into the chamber is used as a rotation driving source of the rotating shaft, the overall configuration can be simplified as compared with a case where the chamber temperature maintaining means and the rotating shaft driving means are separated. In addition, when a separate driving means is provided, a motor that is generally used as the driving means has a portion that generates heat, so that a structure that thermally shuts off the driving means and the temperature maintaining gas flow path is provided. Will be needed.
Otherwise, the heat generated by the driving means raises the temperature of the temperature maintaining gas, making it difficult to maintain superconductivity. On the other hand, in the present invention, since it is not necessary to separately provide a driving means for the rotating shaft, it is not necessary to provide the above-described thermal cutoff structure, and the configuration can be further simplified.

Furthermore, for example, if the rotation of the rotating shaft is detected in the chamber, accurate rotation detection can be performed without the inconvenience associated with the conventional frost and water droplets.

[Brief description of the drawings]

1 and 2 relate to an embodiment of the present invention, and FIG.
The figure is a longitudinal sectional side view showing the basic configuration of the superconducting magnetic bearing device,
FIG. 2 is a sectional view taken along the line II-II of FIG. 1 ... rotating shaft, 2 ... chamber, 3 ... electromagnet, 4 ... gas supply means, A, B ... superconducting material for thrust support, C, D ... superconducting material for radial support.

Claims (1)

(57) [Claims] 1. A superconducting magnetic bearing device for supporting a rotating shaft in a thrust direction and a radial direction by utilizing a force generated on a magnet of a superconducting material, wherein the superconducting material for a thrust support and a radial support provided on the rotating shaft is provided. A magnet fixedly arranged to face each of these superconducting materials, a chamber surrounding the rotation axis, and a temperature maintaining gas for keeping the superconducting materials at a critical temperature or lower is supplied into the chamber. A superconducting gas turbine, wherein the rotating shaft is provided with a turbine section for receiving the temperature maintaining gas supplied into the chamber and rotating the rotating shaft. Magnetic bearing device.