JPH08284957A - Radial bearing - Google Patents

Abstract

PURPOSE: To provide a radial bearing capable of stably support a rotary body in a non-contact manner by the magnetic repulsion which is sufficiently large to the magnetic flux from a permanent magnet provided on the rotary body. CONSTITUTION: A bearing to rotatably support a rotary body 2 in combination with a magnet 24 provided on the rotary body is provided a high temperature super-conductive body 23 where the surface on which the critical current value is higher than that of the other surface is positioned in the same direction as the center axis of the rotary body.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radial bearing using a high temperature superconductor.

[0002]

2. Description of the Related Art A high-temperature superconductor is used as a component of a bearing that rotatably supports a rotating body, as one of the uses of its characteristics. This bearing is used in combination with a magnet provided in a rotating body, and a magnetic repulsive force is applied to a magnet of the rotating body by a high temperature superconductor to float and support the rotating body from the bearing.

This bearing is used, for example, to support a rotating portion in a power generator / motor. FIG. 3 shows the structure of a conventional generator / motor using a bearing. In the figure, reference numeral 1 denotes a container, and a rotor shaft 2 is provided upright inside the container 1. A flywheel 3 for accumulating the rotational energy is formed below the rotor shaft 2. 4 is a rotor attached to the upper end of the rotor shaft 2,
5 is a stator attached to the container 1 surrounding the rotor 4,
Reference numeral 6 denotes a stator coil provided on the stator 5.

Reference numeral 7 is a permanent magnet for a radial bearing, which is provided on the upper and lower portions of the rotor shaft 2 and is made of, for example, a neodymium-based material, and is formed in a cylindrical shape and fitted to the rotor shaft 2.

Reference numeral 8 denotes a radial bearing which is arranged facing the respective permanent magnets 7 and is provided in the container 1. The radial bearing 8 is formed of a high temperature superconductor, for example, a sintered body of yttrium-based material, and is shown in FIG. The permanent magnet 7 has a cylindrical body as shown in
It is arranged around.

The radial bearing 8 applies a magnetic force in the opposite direction along the radial direction of the rotor shaft 2 to the magnetic force of each permanent magnet 7 for the radial bearing provided on the rotor shaft 2. The shaft 2 is rotatably supported without contact.

Reference numeral 9 denotes a permanent magnet for a thrust bearing provided on the upper surface and the lower surface of the flywheel 3 of the rotor shaft 2, which has a circular ring shape made of, for example, a neodymium-based material. It is arranged concentrically with the slave shaft 2 and attached to the flywheel 3.

Reference numeral 10 denotes a thrust bearing which is arranged in opposition to each permanent magnet 9 and is provided in the container 1. This thrust bearing is made of a high temperature superconductor, for example, a sintered body of yttrium-based material, and is the same as the permanent magnet 9. It has a circular ring shape as shown in FIG.

The thrust bearing 10 applies a magnetic force in the opposite direction along the axial direction of the rotor shaft 2 to the magnetic force of each permanent magnet 9 for thrust bearing provided on the flywheel 3 to flywheel 3. Is rotatably supported without contact.

These bearings 8 and 10 support the rotor shaft 2 by levitating it in a non-contact state by utilizing the principle that magnetic repulsion force is generated when the magnetic flux generated from a permanent magnet is restricted inside the high temperature superconductor. The feature is that there is almost no bearing friction loss.

That is, as shown in FIG. 5, when the north poles of the permanent magnets 7, 9 approach the bearings 8, 10, the bearings 8,
An N pole is generated on the surface of 10 facing the permanent magnets 7 and 9, and an annular current flows in such a direction as to generate a magnetic repulsive force that prevents the magnetic flux from entering from the permanent magnets 7 and 9. Therefore, this current supports the rotor, that is, the rotor shaft 2 and the flywheel 3 in a non-contact state by the magnetic repulsive force against the magnetic flux of the permanent magnet provided in the rotor.

The high temperature superconductor forming the bearings 8 and 10 is
For example, the yttrium-based material has a crystal structure as shown in FIG. This crystal structure has a c-axis direction and a and b directions perpendicular to the c-axis direction.
As shown in FIGS. 7A and 7B, the conventional superconductor bearings 8 and 10 are formed with the c-axis direction of the crystal aligned with the direction of the central axis of the bearing.

Reference numerals 11 and 12 denote liquid nitrogen pockets provided in the container 1 so as to surround the bearings 8 and 10, in which liquid nitrogen for cooling the bearings 8 and 10 to a critical temperature of 90 K or less is stored. A liquid nitrogen supply tank 13 supplies liquid nitrogen to the liquid nitrogen pockets 11 and 12. 14 is a liquid nitrogen supply tank 13 and liquid nitrogen pockets 11 and 12
This is a valve provided in the passage that connects with.

The container 1 is evacuated by a vacuum pump 15 via a valve 16 to reduce windage loss when the rotor shaft 2 rotates. In the generator / motor configured as described above, the rotor shaft 2 is rotated by the combination of the rotor 4 and the stator 5. The flywheel 3 stores the kinetic energy of the rotor shaft 2, and the stored energy is represented by the following formula.

E = 1 / 2Iω ² E: kinetic energy I: moment of inertia (in the case of a right cylinder rotor: I = m
^{(R 2/2), m} : a right circular cylinder rotor, r: a right circular cylinder radius) omega: rotational angular speed rotor shaft 2 floats in a non-contact state by the combination of the permanent magnet 7, 9 and the bearing 8, 10 Supported. Each superconductor bearing 8, 10 is cooled with liquid nitrogen.

FIG. 4 shows the motion modes of the flywheel 3. A is in a standby state, and the flywheel 3 rotates at a low speed. B is an input state in which energy is externally input to the flywheel 3, and the rotational speed of the flywheel 3 gradually increases, and energy is input as rotational energy.
C is energy storage / holding state, D is flywheel 3
Shows the state in which the rotational energy of is released to the outside, and the rotational speed of the flywheel 3 decreases.

[0017]

However, the conventional superconductor bearings 8 and 10 have the following problems. In the high temperature superconductor, the critical current in the ab plane of the crystal shown in FIG.
Greater than the critical current in the c-axis direction of the crystal, eg a
Critical current in b-plane 3: Critical current in c-axis direction 1
There is a property. That is, a of the crystal of the high temperature superconductor
The magnetic repulsive force against the magnetic flux generated from the outside and generated by the current on the b-plane is
It is larger than the magnetic repulsive force against the magnetic flux generated from the outside and invading from the outside.

As described above, the conventional bearings 8 and 10 are formed so that the c-axis direction of the high temperature superconductor is along the bearing center axis as shown in FIGS. 3 and 7. Therefore, in the thrust bearing 10, the ab plane of the crystals of the high temperature superconductor matches the direction of the bearing surface facing the rotor, and the permanent magnet 9 that is the rotor provided on the flywheel 3 of the rotor shaft 2 is used. To face.

That is, in the thrust bearing 10, the ab plane having a large magnetic repulsive force against the magnetic flux generated from the outside and generated by the current is aligned with the direction of the bearing surface, and is installed on the flywheel 3 of the rotor shaft 2. It faces the magnet 9.
As a result, the flywheel 3 can be stably supported in a non-contact state by a sufficiently large magnetic repulsive force against the magnetic flux from the permanent magnet 9 provided on the flywheel 3.

On the other hand, in the radial bearing 8, the ab plane of the crystals of the high temperature superconductor does not match the orientation of the bearing surface facing the rotor, and other ac planes and bc planes are provided on the rotor shaft 2. It faces the permanent magnet 7, which is a rotating body.

That is, the ab surface having a large magnetic repulsive force against the magnetic flux generated from the outside generated by the current does not match the direction of the bearing surface, and the other surface having a small magnetic repulsive force against the magnetic flux entering from the outside is the bearing surface. It faces the permanent magnet 7 provided on the rotor shaft 2 in the same direction. As a result, in the radial bearing 10, the magnetic repulsive force against the magnetic flux from the permanent magnet 7 provided on the rotor shaft 2 is not large enough to stably support the rotor shaft 2 in a non-contact state, It was difficult to stably support the rotor shaft 2 in a non-contact state.

The present invention has been made in view of the above circumstances, and a radial bearing capable of stably supporting a rotating body in a non-contact state by a sufficiently large magnetic repulsive force against a magnetic flux from a permanent magnet provided on the rotating body. The purpose is to provide.

[0023]

In order to achieve the above-mentioned object, the radial bearing of the present invention is a bearing in which a rotating body is rotatably supported in combination with a magnet provided on the rotating body and has a critical current value of It is characterized in that it is provided with a high temperature superconductor in which a surface higher than other surfaces is arranged in the same direction as the central axis of the rotating body.

[0024]

In the radial bearing of the present invention, specifically, the c-axis of the crystal of the high temperature superconductor is provided in a direction orthogonal to the bearing surface facing the magnet, and the ab surface faces the bearing surface facing the magnet. It is provided in accordance with. Therefore, in the high temperature superconductor of the radial bearing of the present invention, the surface having a large magnetic repulsive force against the magnetic flux generated by the current and invading from the outside matches the direction of the bearing surface, and the permanent magnet provided in the rotating body. opposite. As a result, the radial bearing of the present invention can stably support the rotating body in a non-contact state by a sufficiently large magnetic repulsive force generated by the current flowing through the bearing surface.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. This embodiment is applied to a radial bearing that supports a rotor shaft in the generator / motor shown in FIG. FIG. 1 shows the radial bearing of this embodiment, and FIG.
It shows the part where the radial bearing is built into the generator / motor shown in. 2, the same parts as those in FIG. 3 are indicated by the same reference numerals.

In the figure, reference numeral 21 denotes a radial bearing, which is a bearing bush 22 and this bearing bush 22.
And a plurality of high temperature superconductors 23 embedded in. The bearing bush 22 has a cylindrical shape, and the inner diameter thereof is a size surrounding the periphery of the permanent magnet 25 provided on the rotor shaft 2 in the generator / motor, as described later. The bearing bush 22 is made of a metal such as copper or aluminum.

The high temperature superconductor 23 is made of a high temperature superconducting material such as an yttrium-based material. The high temperature superconductor 23 is, for example, in the shape of a round bar, and is formed so that the direction of the c-axis of the crystal coincides with the direction of the central axis of the round bar. Therefore, the end surface 23a of the high temperature superconductor 23 in the shape of a round bar is the ab surface.

A plurality of high-temperature superconductors 23 are prepared, and the rod-shaped high-temperature superconductors 23 are oriented inside the bearing bush 22 so as to be positioned at right angles to the central axis O of the bearing bush 22. The bearing bushes 22 are set and arranged side by side in the circumferential direction of the bearing bush 22 and embedded. That is, the plurality of high-temperature superconductors 23 are radially arranged around the center axis O of the bearing bush 22 and are radially arranged and embedded in the bearing bush 22.

As a result, the ab surface which is the end surface 23a of the rod-shaped high temperature superconductor 23 is located in the bearing bush 22 along the direction of the central axis O thereof. In this radial bearing 21, the surface along the direction of the central axis O of the bearing bush 22 becomes the bearing surface, as will be described later, but the end surface 23 of the high temperature superconductor 23.
The ab surface which is a has the same direction as this bearing surface. Also,
In this embodiment, one end surface 22a of the high temperature superconductor 23 is
Is exposed to the outside at the inner peripheral surface of the bearing bush 22 having a cylindrical shape. The inner peripheral surface of the bearing bush 22 and the exposed end surface 23a of the high-temperature superconductor 23 serve as a bearing surface that directly faces the permanent magnet 25 provided on the rotor shaft 2.

Here, the direction of the central axis of the bearing bush 22 coincides with the direction of the central axis of the rotor shaft 2 which is a rotating body supported by the bearing bush 22. Therefore, the c-axis of the crystal of the high temperature superconductor 23 is located in the direction perpendicular to the central axis of the rotor axis 2, and the end face 2 which is the ab plane of the high temperature superconductor 23.
2a is located along the direction of the central axis of the rotor shaft 2.

As described above, in each high-temperature superconductor 23, the ab plane, which has a large magnetic repulsive force against the magnetic flux generated from the outside and which is generated by the electric current, is a rotating body in conformity with the orientation of the bearing surface facing the rotating body. Permanent magnet 25 provided on the rotor shaft 2
To face.

As shown in FIG. 1, the group of high temperature superconductors 23 arranged in this way are arranged in a plurality of stages in the direction of the central axis O of the bearing bush 22 and embedded. The radial bearing 21 is provided in the container 1 so as to surround a magnet portion, which will be described later, provided on the rotor shaft 2. The configuration of the magnet section will be described. In FIG. 2, reference numeral 24 denotes a magnet holder, which is a cylindrical body and is fitted and fixed to the rotor shaft 2.
The magnet holder 24 has a circular ring-shaped permanent magnet 2
5 is arranged so as to face the group of high temperature superconductors 23 radially embedded in the bearing bush 22 of the radial bearing 21 and is embedded therein. The outer peripheral surface of the permanent magnet 25 is exposed at the outer peripheral surface of the magnet holder 24.

Further, the circular ring-shaped permanent magnet 25 faces the group of high temperature superconductors 23 of each stage arranged in the bearing bush 22 in the central axis direction of the bearing bush 22, and is spaced in the central axis direction of the magnet holder 24. There are a plurality of embedded and embedded.
Each permanent magnet 25 is arranged so that the N pole and the S pole face each other.

The reason why the permanent magnets 25 are divided and provided so as to face the groups of high temperature superconductors 23 in each stage is to increase the radial magnetic flux of the permanent magnets. In the radial bearing 21 incorporated in the generator / motor in this way, the high temperature superconductor 23 of each stage embedded in the bearing bush 22 is attached to the magnet holder 24 provided on the rotor shaft 2 as shown in FIG. Each circular ring-shaped permanent magnet 25 held
To face. Each permanent magnet 25 is a high temperature superconductor 23 of each stage.
The magnetic flux acts in the radial direction. As a result, in the ab surface, which is the end surface 23a of the high temperature superconductor 23 of each stage of the radial bearing 21 facing the permanent magnets 25, a magnetic repulsive force that prevents magnetic flux from entering from the permanent magnets 25 is generated. An annular current flows.

Therefore, the ab surface, which is the end face 23a of the high temperature superconductor 23 in each stage facing the permanent magnets 25 due to this annular current, acts against the magnetic flux from the permanent magnets 25 provided on the rotor shaft 2. Magnetic repulsion occurs. Then, the magnetic force from each permanent magnet 25 provided on the rotor shaft 2 and the high temperature superconductor 23 at each stage of the radial bearing 21.
The mutual repulsion of the magnetic flux from the permanent magnets 25 and the magnetic repulsion force causes the rotor shaft 2 to directly contact the inner peripheral surface of the bearing bush 22 of the radial bearing 21 and the ab surface of the high temperature superconductor 23 at each stage. It is supported in a non-contact state without contact.

Here, the high temperature superconductor 23 in the radial bearing 21 is provided so that the c axis of the crystal is orthogonal to the bearing surface facing the permanent magnet 25, and the ab of the crystal is ablated.
The surface is provided in the same direction as the bearing surface facing the permanent magnet 25. For this reason, the high temperature superconductor 23 at each stage of the radial bearing 21 has a larger magnetic repulsive force with respect to the magnetic flux generated from the outside and invading from the outside, as compared with the ac surface and the bc surface, which are ab and ab. The surface faces the permanent magnet 25 provided on the rotor shaft 2 in the same direction as the bearing surface.

As a result, the high temperature superconductor 23 at each stage of the radial bearing 21 can stably support the rotor shaft 2 in a non-contact state by a sufficiently large magnetic repulsive force generated by the electric current.

Further, in this embodiment, each high temperature superconductor 23
By embedding the bearing bush 22 in the bearing bush 22, the strength of each high-temperature superconductor 23 is increased and each high-temperature superconductor 23 has sufficient rigidity.
I support.

The present invention is not limited to the above-described embodiments, but can be modified in various ways. For example, the radial bearing is not limited to the generator / motor, but can be used for supporting the rotating portion on other equipment. Further, the shape of the high temperature superconductor and the holding structure are not limited to those in the above-mentioned embodiments.

[0040]

As described above, according to the radial bearing of the present invention, the high temperature superconductor is arranged such that the surface having a higher critical current value than the other surface faces the magnet provided on the rotating body. Since, since the surface of the high temperature superconductor has a large magnetic repulsive force against the magnetic flux entering from the outside, which is generated by the current in the high temperature superconductor, the surface of the high temperature superconductor faces the magnet provided on the rotating body in the same direction as the bearing surface. As a result, the rotating body can be stably supported in a non-contact state by a sufficiently large magnetic repulsive force generated by the current flowing through the bearing surface.

[Brief description of drawings]

FIG. 1A is a cross-sectional view showing a radial bearing according to an embodiment of the present invention broken along an axial direction. (B) is sectional drawing which fracture | ruptures and shows the radial bearing in the Example along a diameter direction.

FIG. 2A is a cross-sectional view showing a structure in which the radial bearing of the same embodiment is incorporated in a power generator / motor cut along the axial direction. (B) is sectional drawing which fractures | ruptures and shows the same structure along a diameter direction.

FIG. 3A is a cross-sectional view showing a conventional generator / electric motor incorporating a bearing. 3B is a sectional view taken along line XX of FIG.

FIG. 4 is a diagram showing an operation mode of a conventional generator / motor.

FIG. 5 is a diagram showing the relationship between the magnetic force of a high temperature superconductor and the magnetic force of a magnet.

FIG. 6 is a diagram showing a crystal structure of a high temperature superconductor.

FIG. 7A is a diagram showing a conventional bearing. (B) is a figure which shows the bearing of a prior art example.

[Explanation of Codes] 1 ... Container, 2 ... Rotor shaft, 3 ... Flywheel, 7 ... Permanent magnet, 8 ... Bearing, 9 ... Permanent magnet, 10 ... Bearing, 21 ... Radial bearing, 22 ... Bush, 23 ... High temperature Superconductor 24 ... Magnet holder, 25 ... Permanent magnet.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Masaharu Minami 2-1-1, Niihama, Arai-cho, Takasago, Hyogo Prefecture Mitsubishi Heavy Industries, Ltd. Takasago Laboratory (72) Inventor, Makoto Takenaka 2--1, Niihama, Arai-cho, Takasago, Hyogo Prefecture No. 1 Mitsubishi Heavy Industries, Ltd. Takasago Laboratory (72) Inventor Masao Takahashi 2-1-1 Niihama, Arai-cho, Takasago-shi, Hyogo Prefecture Mitsubishi Heavy Industries Ltd. Takasago Laboratory (72) Inventor Yu Kawashima Niihama, Arai-cho, Takasago-shi Hyogo Prefecture 1-1 Mitsubishi Heavy Industries, Ltd. Takasago Plant (72) Inventor Tatsuya Sato 2-1-1, Niihama, Arai-cho, Takasago, Hyogo Prefecture Mitsubishi Heavy Industries Ltd. Takasago Plant

Claims (1)

[Claims] 1. In a bearing that rotatably supports a rotating body in combination with a magnet provided on the rotating body, a surface having a higher critical current value than other surfaces is the same as the central axis of the rotating body. A radial bearing having a high-temperature superconductor arranged in a facing direction.