JPH05164131A - Superconductive bearing device - Google Patents

Abstract

PURPOSE:To increase load capacity and rigidity in the radial direction without complicating or enlarging a structure. CONSTITUTION:A permanent magnet 10 is fixed to the periphery of a. rotation axis 5. The permanent magnet 10 is composed of a plurality of permanent magnet elements 11a, 11b, 11c which are respectively axially magnetized and serially combined. The adjacent permanent magnet elements 11a, 11b and 11c have the same poles opposed to each other. In a housing 12 provided on the circumference of the permanent magnet 10, a superconductor 9 is held. A coolant is fed to a cooling jacket 15, so that the superconductor 9 is brought into a superconductive state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The superconducting bearing device according to the present invention is used, for example, to support a rotating shaft rotating at high speed in a non-contact state.

[0002]

2. Description of the Related Art A rotating shaft rotating at a high speed cannot be supported by a normal bearing device such as a sliding bearing or a rolling bearing, and it is necessary to support the rotating shaft in a non-contact state. As described above, as a bearing device for supporting the rotating shaft in a non-contact state, a superconducting bearing device that supports the rotating shaft in a floating state by utilizing the pinning effect of the superconductor has been studied in recent years.

11 to 12 show, among the conventionally proposed superconducting bearing devices, those described on page 18 of "Summary of Abstracts of 1991 Spring Low Temperature Engineering and Superconductivity Society".

This conventionally known superconducting bearing device is intended for bearings in the thrust direction. As shown in FIG. 11 showing the principle, the annular permanent magnet 1 is made of a plurality of superconducting materials. The pellets 2 and 2 are opposed to each other. The permanent magnet 1 and the pellets 2 and 2 are embedded in copper disks 3 and 4, respectively. The pellets 2 made of an yttrium-based oxide superconducting material (for example, YBa ₂ Cu ₃ Ox) are arranged concentrically and face the permanent magnet 1.

By cooling the disk 4 in which the pellets 2 and 2 are embedded to bring the pellets 2 and 2 into a superconducting state, a pinning effect that acts between the pellets 2 and 2 and the permanent magnet 1 is obtained. A force is generated in a direction that prevents the distance between the pellets 2 and 2 and the permanent magnet 1 from changing. That is, when the pellets 2 and 2 are in a superconducting state, the magnetic flux emitted from the permanent magnet 1 is restrained in the pellets 2 and 2.
Pinning force is generated.

When the distance between the permanent magnet 1 and the pellets 2 and 2 tends to increase due to this pinning force, an attractive force acts between the two members 1 and 2, and the permanent magnet 1 on the contrary.
When the distance between the pellets 2 and the pellets 2 tends to be narrowed, a repulsive force acts between the members 1 and 2. Due to such attraction or repulsion, the distance between the permanent magnet 1 and the pellets 2, 2 is kept constant. Also, the positional relationship between the permanent magnet 1 and the pellets 2 and 2 is prevented from shifting in the surface direction based on the pinning force. Therefore, if the permanent magnet 1 is fixed to the rotary shaft, the rotary shaft can be rotatably supported in a floating state.

FIG. 12 shows a state in which the rotary shaft 5 is rotatably supported by the superconducting bearing device having the above-described principle. A pair of circular plates 4a and 4a in which a plurality of pellets 2 and 2 are respectively embedded are arranged in parallel with each other with a space therebetween, and can be freely cooled by liquid nitrogen stored in the cooling jacket 7 of the housing 6. There is. An annular plate 3a is fixed between the pair of annular plates 4a and 4a at an intermediate portion of the rotary shaft 5 inserted through the inside of the pair of annular plates 4a and 4a. The permanent magnets 1 and 1 embedded in the upper and lower surfaces of the circular plate 3a face the pellets 2 and 2, respectively. An electric motor 8 is provided at the end of the rotary shaft 5 so that the rotary shaft 5 can be driven to rotate.

Liquid nitrogen is fed into the cooling jacket 7 and the pellets 2 and 2 embedded in the respective discs 4a and 4a.
In the superconducting state, the circular plate 3a fixed to the intermediate portion of the rotary shaft 5 does not move far and far with respect to the circular plates 4a and 4a, and the rotary shaft 5 is in the floating state. The rotation shaft 5 can be rotated.

[0009]

However, in the superconducting bearing device including the structure proposed above, the rigidity in the radial direction tends to be lower than the rigidity in the thrust direction. In the case of the structure shown in FIG. 12, since the pellets 2 and 2 made of a superconducting material and the permanent magnets 1 and 1 are opposed to each other in the thrust direction, the rigidity and load capacity particularly in the radial direction are improved. Although it is low, even if the superconductor 9 and the permanent magnet 1 magnetized in the axial direction are made to face each other in the radial direction, as shown in FIG. It is not always possible to obtain sufficient radial rigidity and load capacity although the rigidity and load capacity are improved.

That is, in the superconducting bearing device, since the magnetic flux generated from the permanent magnet 1 is pinned (restricted) inside the superconductor 9 (pellets 2 and 2), the rigidity and the rigidity in the magnetizing direction of the permanent magnet 1 are increased. Even if the load capacity could be increased, it was difficult to increase the rigidity and the load capacity in the direction perpendicular to the magnetization direction.

The present invention has been conceived in view of the above circumstances, and provides a superconducting bearing device having a simple structure and a large rigidity and load capacity in the direction perpendicular to the magnetizing direction of the permanent magnet. It is a thing.

[0012]

A superconducting bearing device of the present invention comprises a shaft, a mating member which is provided around the shaft so as to be rotatable relative to the shaft, an outer peripheral surface of the shaft and a mating member. A permanent magnet fixed to one peripheral surface of the inner peripheral surface and a superconductor fixed to the other peripheral surface and facing the permanent magnet with a radial gap therebetween.

In particular, in the superconducting bearing device of the present invention, a plurality of permanent magnet elements, each of which is magnetized in the axial direction of the above-mentioned permanent magnet, are arranged in series in the axial direction and have the same poles. It is configured by combining them in a state of facing each other.

[0014]

In the superconducting bearing device of the present invention configured as described above, the magnetic flux generated from the end faces of the adjacent permanent magnet elements is
They repel each other and spread in a direction perpendicular to the axial direction.
Therefore, a magnetic flux in a direction perpendicular to the magnetization direction of each permanent magnet element exists around the permanent magnet composed of a plurality of permanent magnet elements.

As a result, a large force can be applied between the permanent magnet and the superconductor based on the pinning force, and a superconducting bearing device having a large rigidity in the radial direction and a large load capacity can be constructed.

[0016]

1 to 4 show an embodiment of the present invention. The permanent magnet 10 is externally fitted and fixed to the outer peripheral surface of the intermediate portion of the rotary shaft 5 provided in the vertical direction. This permanent magnet 10
Each of the three permanent magnet elements 11a and 1a is formed in an annular shape and is magnetized in the axial direction (vertical direction in FIG. 1).
It is configured by arranging 1b and 11c in series along the axial direction. In addition, adjacent permanent magnet elements 11a, 1
Spacers 16 and 16 made of a non-magnetic material are sandwiched between 1b and 11b and 11c, respectively, or a space is provided between them. Furthermore, adjacent permanent magnet elements 11a, 11
As shown in FIG. 2, b and 11b and 11c have the same poles (S poles and N poles) opposed to each other.

On the other hand, around the permanent magnet 10, there is provided a housing 12 having a U-shaped cross section with an opening on the inner peripheral side and having an annular shape as a whole. Then, an annular superconductor 9 which is in a superconducting state at the liquid nitrogen temperature, such as YBa ₂ Cu ₃ Ox, is fixed to the opening of the inner side of the housing 12. A coolant supply port 13 is provided on a part of the outer surface of the housing 12, and a coolant discharge port 14 is provided on the opposite side of the housing 12.
A coolant such as liquid nitrogen can be supplied freely into the cooling jacket 15 surrounded by the inner peripheral surface of 2.

When the rotating shaft 5 is supported in a floating state by the superconducting bearing device of the present invention configured as described above,
With the rotary shaft 5 raised slightly from the state of use, the coolant is fed into the cooling jacket 15,
After cooling the superconductor 9 into a superconducting state, the force that has raised the rotating shaft 5 is released. As a result, the rotary shaft 5 is slightly lowered due to its own weight. In this state, the rotary shaft 5
The magnetic flux emitted from the permanent magnet 10 fixed to the
It is pinned inside to prevent the rotary shaft 5 from further descending.

Particularly, in the case of the superconducting bearing device of the present invention, as shown in FIG. 3, adjacent permanent magnet elements 11a, 11b,
The magnetic fluxes emitted from the end surface of 11c repel each other and spread in a direction perpendicular to the axial direction. Thus, the permanent magnet elements 11a, 11b, 1b, 1b, 1c are arranged around the permanent magnet 10 composed of the three permanent magnet elements 11a, 11b, 11c.
A magnetic flux exists in a direction perpendicular to the magnetization direction of 1c.

By pinning the magnetic flux in the superconductor 9, the force for holding the permanent magnet 10 in the same position is large in the direction of the magnetic flux and small in the direction perpendicular to the direction of the magnetic flux. Therefore, as described above, each permanent magnet element 1
When there is a magnetic flux in a direction perpendicular to the magnetizing directions of 1a, 11b and 11c, these permanent magnet elements 11a, 11b and 11c
The force for holding the permanent magnet 10 constituted by c in the radial direction becomes large. In other words, the rigidity and load capacity of the superconducting bearing device in the radial direction are increased.

When the present inventor analyzed the magnetic field lines and the magnetic flux density distribution of the permanent magnet 10 constituting the superconducting bearing device of the present invention by the finite element method, the results shown in FIGS. 3 to 4 were obtained. 3 shows the magnetic force lines, and FIG. 4 shows the magnetic flux density distribution in the axial direction of the portion distant from the outer peripheral surface of the permanent magnet 10 in the radial direction by a constant distance. As shown in Fig. 2, the solid line in Fig. 4 shows an inner diameter of 25m.
The magnetic flux density distribution is 0.5 mm away from the outer peripheral surface of the permanent magnet 10 having m, outer diameter 36 mm, and length 20 mm, the broken line is the magnetic flux density distribution 0.75 mm apart, and the chain line is 1 mm apart. The magnetic flux density distribution of each portion is shown. The permanent magnet 10 is 24 mm to 4 mm on the horizontal axis of FIG.
It exists between 4 mm.

On the other hand, the magnetic lines of force of a single permanent magnet 1 as shown in FIG. 5 (which is not a combination of a plurality of permanent magnet elements) constituting the superconducting bearing device shown in FIG. 13 are shown in FIG. Similarly, the magnetic flux density distribution is as shown in FIG. Also, the three permanent magnet elements 11a, 11b,
Even when 11c are combined in series, when different poles (S pole and N pole, N pole and S pole) are opposed to each other as shown in FIG. 8, the magnetic force lines are the same as shown in FIG. The magnetic flux density distribution is as shown in FIG.

The vertical axis of FIG. 4 showing the magnetic flux density distribution of the permanent magnet 10 used in the present invention is a little more than twice the vertical axis of FIGS. 7 and 10 showing the magnetic flux density distribution of other permanent magnets. It represents the magnetic flux density.

Comparing FIGS. 3, 6 and 9 showing the lines of magnetic force and FIGS. 4, 7 and 10 showing the magnetic flux density distribution, the radial direction of the permanent magnet 10 used by being incorporated in the superconducting bearing device of the present invention. It is understood that the magnetic flux density is high, and as a result, the rigidity and load capacity in the radial direction of the superconducting bearing device become much larger.

That is, when the superconducting bearing apparatus as shown in FIGS. 1 and 13 is constructed, the load capacity in the radial direction of this superconducting bearing apparatus is the magnetic flux existing between the permanent magnets 10 and 1 and the superconductor 9. The higher the density, the larger. Comparing FIGS. 3, 6, 9 and FIGS. 4, 7, 10 on this premise, the superconducting bearing device of the present invention incorporating the permanent magnet 10 having the above-described structure can obtain a large radial load capacity. I understand.

On the other hand, the rigidity of the superconducting bearing device in the radial direction increases as the magnetic flux strength of the permanent magnets 10 and 1 changes greatly in the radial direction. In other words, the magnetic flux density distribution shown in FIGS.
Then, the greater the difference between the solid line and the broken line and the greater the difference between the broken line and the chain line, the greater the radial rigidity. Comparing FIGS. 4, 7 and 10 on this assumption, it can be seen that the superconducting bearing device of the present invention can obtain a large radial rigidity.

In the illustrated embodiment, non-magnetic spacers 16 and 16 are sandwiched between the adjacent permanent magnet elements 11a and 11b and between the adjacent permanent magnet elements 11b and 11c, respectively. Since the air gap is provided, each permanent magnet element 11a,
Of the end faces of 11b and 11c, the magnetic flux emitted from the faces facing each other is reliably derived in the radial direction. On the other hand, when the end faces of the permanent magnet elements 11a, 11b, 11c are directly brought into contact with each other, the magnetic flux emitted from the end faces is hard to be derived in the radial direction, and the load capacity and rigidity in the radial direction are reduced. May not always be high enough.

In the illustrated embodiment, the case where the rotary shaft 5 is supported inside the fixed housing 12 in a floating state has been described, but conversely, a rotor or the like is provided around the fixed pivot. It can also be supported in a floating state. In this case,
The permanent magnet 10 is fixed to the inner peripheral surface of the rotor, the superconductor 9 is fixed to the outer peripheral surface of the pivot, and the cooling jacket 15 is provided on the pivot.

[0029]

Since the superconducting bearing device of the present invention is constructed and operates as described above, it is possible to increase the load capacity and rigidity in the radial direction in spite of its simple structure and small size. For this reason, it becomes possible to support the rotating shaft and the like, which are heavy in weight.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of the present invention.

FIG. 2 is a vertical sectional view of a permanent magnet used in the present invention.

FIG. 3 is a diagram showing magnetic lines of force of this permanent magnet.

FIG. 4 is a diagram similarly showing a magnetic flux density distribution.

FIG. 5 is a sectional view of a single permanent magnet.

FIG. 6 is a diagram showing magnetic lines of force of this permanent magnet.

FIG. 7 is a diagram similarly showing a magnetic flux density distribution.

FIG. 8 is a longitudinal sectional view of a permanent magnet in which permanent magnet elements are combined in a state different from that of the present invention.

FIG. 9 is a diagram showing magnetic lines of force of this permanent magnet.

FIG. 10 is a diagram showing a magnetic flux density distribution.

FIG. 11 is a perspective view showing the basic principle of a conventional example.

FIG. 12 is a perspective view showing a specific configuration of a conventional example.

FIG. 13 is a longitudinal sectional view of a superconducting bearing device considered prior to the present invention.

[Explanation of symbols]

 1 Permanent Magnet 2 Pellet 3 Disc 3a Disc 4 Disc 4a Disc 5 Rotating shaft 6 Housing 7 Cooling jacket 8 Electric motor 9 Superconductor 10 Permanent magnet 11a Permanent magnet element 11b Permanent magnet element 11c Permanent magnet element 12 Housing 13 Coolant Supply Port 14 Coolant Discharge Port 15 Cooling Jacket 16 Spacer

Claims (1)

[Claims] 1. A shaft, a mating member provided around the shaft so as to be rotatable relative to the shaft, and fixed to one peripheral surface of an outer peripheral surface of the shaft and an inner peripheral surface of the mating member. A permanent magnet, and a superconductor fixed to the other circumferential surface and facing the permanent magnet with a radial gap therebetween, the superconducting bearing device comprising: A superconducting bearing device constituted by combining a plurality of magnetized permanent magnet elements in series in the axial direction with the same poles facing each other.