JPH0921421A - Superconductive bearing for rotary equipment and electric power storing flywheel using this superconductive bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a superconductive bearing for rotary equipment, which can obtain a large levitation force with the combination of a permanent magnet at a small diameter and a superconductor, and provide an electric power storing flywheel using this superconductive bearing. SOLUTION: Permanent magnets are superposed on each other in a rotating member at multiple stages in the axial direction, and a superconductor is arranged in a fixed member opposite to the permanent magnet so as to form a superconductive bearing with the pin-lock effect. In an electric power storing flywheel, a hollow outer rotor 5 is stood inside of a rotating outer ring 3, and permanent magnets 10 are superposed at multiple stages in the axial direction along the inner periphery of the outer rotor 5, and a superconductor 11 is arranged in the periphery of a fixed shaft 2, which is inserted into the outer rotor 5, opposite to the permanent magnets 10, and the outer rotor 5 is levitated by the pin-lock effect.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a superconducting bearing used in a rotating device such as a flywheel for power storage, and more particularly to a superconducting rotating device in which a large supporting force can be obtained by combining a small-diameter permanent magnet and a superconductor. The present invention relates to a bearing and a flywheel for power storage using the bearing.

[0002]

2. Description of the Related Art There is known a concept of a flywheel for storing electric power, which stores electric power energy in the form of kinetic energy in order to store the surplus electric energy and to take out the electric power when it is insufficient. The flywheel for power storage can store a large amount of kinetic energy by rotating a rotating body such as a top having a predetermined mass (inertial mass) at a very high speed. Since the mass is large and the rotation is very fast, it is important to suppress the friction loss in the bearing.

A flywheel for electric power storage, which has been conventionally envisioned, has a rotating outer ring portion 41 as shown in FIG.
A rotary body composed of the shaft core 42 and the shaft core 42 connected thereto is provided, and the magnetic bearing 43 for levitation, the radial control type magnetic bearing 44, and the generator motor 4 are provided along the axial direction of the shaft core 42.
5 are arranged in series. The levitation magnetic bearing (thrust bearing) 43 is composed of a superconducting bearing utilizing the property of superconductivity.

The superconducting bearing is known from Japanese Patent Laid-Open No. 6-233479, and the enlarged diameter portion 4 is provided on the outer circumference of the shaft center portion 42.
6 is provided, and the permanent magnet 47 is arranged on the lower surface of the expanded diameter portion 46. By providing a superconductor facing the permanent magnet 47, a magnetic levitation force is obtained to levitate the entire rotating body. Since the levitation force that can be obtained per unit area is limited, the ring-shaped permanent magnets 47 having different diameters are arranged concentrically to obtain the area facing the superconductor.

[0005]

By the way, in order to increase the storage capacity of the flywheel for power storage, it is necessary to increase the size, weight and speed of the flywheel. As the weight increases, the magnetic bearing for levitation is required to have increased levitation force.
For that purpose, the diameter of the enlarged diameter portion is increased in order to increase the area facing the superconductor. Therefore, the diameter of the permanent magnet arranged outside the expanded diameter portion becomes very large.

However, if the diameter of the permanent magnet becomes large, the centrifugal force becomes large, and if the breaking strength is not enough to withstand this centrifugal force, the permanent magnet will break. Therefore, the diameter of the permanent magnet cannot be made too large.

Further, in the conventional flywheel for storing electric power, since the magnetic bearing for levitation, the radial control type magnetic bearing, and the generator motor are arranged in series in the axial direction, it is necessary to lengthen the axial length. The long shaft length reduces the critical speed. While a high level of control technology is required to stabilize the rotation of the flywheel for power storage, a lower critical speed hinders higher speeds and lowers the efficiency of power storage.

Therefore, an object of the present invention is to solve the above problems and to provide a superconducting bearing for a rotating machine and a flywheel for storing electric power using the superconducting bearing, which can obtain a large levitation force by combining a small-diameter permanent magnet and a superconductor. To provide.

[0009]

In order to achieve the above object, a superconducting bearing of a rotating device according to the present invention is a rotating device which fixes either one of a shaft member and an outer member surrounding the outer periphery and rotates the other. In a superconducting bearing that supports thrust load, permanent magnets are superposed on the rotating member in multiple stages in the axial direction, and a fixed conductor is placed with a superconductor facing the permanent magnets to support the thrust load by pinning effect. It is a thing.

In the flywheel for power storage, a hollow outer rotor is erected inside a rotating outer ring portion, permanent magnets are superposed axially in multiple stages along the inner circumference of the outer rotor, and fixed inside the outer rotor. A superconductor is arranged on the outer periphery of the shaft so as to face the permanent magnet, and the outer rotor is levitated by a pinning effect.

The superconductor may be cooled to a critical temperature at which a pinning effect is produced after the outer rotor is previously positioned at a predetermined axial position.

An electromagnet forming a radial control magnetic bearing and an electromagnet forming a thrust control magnetic bearing may be arranged on the outer circumference of the outer rotor.

With the above structure, between the permanent magnet of the rotating member and the superconductor of the fixed member, and between the permanent magnet of the outer rotor and the superconductor of the fixed shaft in the flywheel for power storage, The pinning effect works. The pinning effect is not due to the property of rejecting the entry of magnetic flux like the Meissner effect, but is due to the property of preserving the magnetic flux in the superconductor, and repels relative movement between the superconductor and the permanent magnet. Generate force. That is, a force repulsive to the fall of the outer rotor is generated, whereby the outer rotor is floated on the fixed shaft in a non-contact manner.

Before the superconductor reaches the critical temperature, the outer rotor is positioned at a predetermined axial position to establish the magnetic flux. Then, when the superconductor is cooled to the critical temperature, superconductivity starts to work, and the pinning effect acts so that the original magnetic flux is preserved.

Since the permanent magnet forming the magnetic bearing for levitation is arranged on the inner circumference of the outer rotor, the electromagnet forming the radial control magnetic bearing and the electromagnet forming the thrust control magnetic bearing are arranged on the outer circumference of the outer rotor. Then, these bearings can be arranged overlapping in the axial direction,
The shaft length can be shortened accordingly.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION A shaft member is formed in a cylindrical shape and fixed to form a fixed shaft, and a superconductor is arranged on the outer periphery of the fixed shaft. On the other hand, a hollow cylindrical outer member that surrounds the outer circumference of the fixed shaft serves as a rotating outer rotor, and permanent magnets are axially stacked in multiple stages along the inner circumference of the outer rotor. On the contrary, when rotating the shaft member to fix the outer member, a permanent magnet may be arranged on the shaft member and a superconductor may be arranged on the outer member. In the superconducting bearing of these rotating devices, the rotating member supports the thrust load in a non-contact manner with the fixed member due to the pinning effect. When the shaft member and the outer member are erected, the superconducting bearing of the present invention becomes a magnetic bearing for levitation. The shaft member and the outer member may be arranged horizontally.

The present invention is not limited to flywheels for the purpose of power storage, but can be used in other rotating equipment such as pumps and turbines.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to the accompanying drawings.

A power storage flywheel using a superconducting bearing according to the present invention has a rotating body 1 as shown in FIG.
And a fixed shaft 2 arranged at the center of the rotating body 1. The rotating body 1 includes an outer ring portion 3 formed in a ring shape and arranged horizontally, and a hub 4 formed in a conical shell shape and inscribed in the outer ring portion 3.
And an outer rotor 5 which is formed in a hollow cylindrical shape and stands vertically through the center of the hub 4. The fixed shaft 2 is inserted into the outer rotor 5, and the upper end and the lower end are fixed.

In this flywheel for power storage, a magnetic bearing 6 for levitation for levitating the rotor and a magnetic bearing 7 for radial control for maintaining the stability of the rotor.
A generator motor 8 for applying a rotational force to the rotating body or vice versa for extracting electric power, and an auxiliary control type thrust bearing 9.

The magnetic bearings 6 for levitation are arranged above and below the outer rotor 5, respectively. In the magnetic bearing 6 for levitation, permanent magnets 10 are stacked in a multi-stage axial direction along the inner circumference of the outer rotor 5, and the fixed shaft 2 is made to face the permanent magnets 10.
The superconductor 11 is arranged on the outer periphery of the. The radial control magnetic bearings 7 are arranged above and below the outer rotor 5 so as to overlap the levitation magnetic bearings 6. The magnetic bearing 7 for radial control is the outer rotor 5
A plurality of laminated steel plates 12 are stacked along the outer circumference in the axial direction, and a plurality of fixed electromagnets (not shown) are provided on the outer circumference. The generator motor 8 is arranged in the middle of the outer rotor 5. The generator motor 8 has permanent magnets 13 stacked axially along the inner circumference of the outer rotor 5 and an electromagnetic coil 14 provided on the outer circumference of the fixed shaft 2. The auxiliary control type thrust bearing 9 is provided with an enlarged diameter portion 15 made of a magnetic material on the outer periphery of the outer rotor 5, and a plurality of fixed electromagnets 16 provided so as to sandwich the enlarged diameter portion 15 from above and below. .

The magnetic bearing 6 for levitation will be described in detail.

As shown in FIG. 2, the permanent magnet 10 has a ring shape having a predetermined height, and has an S pole on the upper surface,
An N pole is formed on the lower surface, an N pole is formed on the upper surface, and an S pole is formed on the lower surface. A large number of the permanent magnets 10 are stacked with the same polarity facing each other via a spacer 21. Superconductor 1
Reference numeral 1 denotes a high-temperature superconductor that exhibits superconductivity even at high temperatures, and this high-temperature superconductor is formed by closely joining pellets 22 that are divided and formed at a predetermined height and a predetermined circumferential angle. As shown in FIG. 3, one pellet 22 has a shape in which a rectangular parallelepiped is curved in an arc shape. The surface of the superconductor 11 is covered with a cryostat 23 using a liquid nitrogen refrigerant.

Next, the operation of the embodiment will be described.

In the power storage flywheel shown in FIG. 1, the outer rotor 5 is first positioned. At that time, the superconductor 11 is set to a temperature higher than the critical temperature and does not exhibit superconductivity. The outer rotor 5 is lifted to the position shown by a lifting device (not shown). In this way, the outer rotor 5 is positioned at a predetermined position in the axial direction before superconducting works, and a magnetic flux is established in the superconductor 11 by the magnetic field created by the permanent magnet 10 of the magnetic bearing 6 for levitation. Then, the temperature of the superconductor 11 is lowered by the cryostat 23. When the superconductor 11 reaches the critical temperature, superconductivity starts to work, and the pinning effect acts so that the original magnetic flux is preserved. That is, even if the lifting device is removed, the outer rotor 5 is kept floating at the positioned position. Of course, since the superconductor 11 does not cause any energy loss as long as it is kept at the critical temperature or lower, it is not necessary to supply electric power or the like.

When electric power is stored in the flywheel for electric power storage, the generator motor 8 acts as a motor to rotate the rotating body 1. The radial control magnetic bearing 7 maintains the stability of the rotating body 1. The magnetic bearing 6 for levitation keeps the rotator 1 floating. In this way, the rotating body 1 is fixed to the fixed shaft 2
Since it is rotated in a non-contact manner, there is no energy loss due to friction, and the power storage flywheel can efficiently store kinetic energy. When extracting electric power, the generator motor 8 is used as a generator.

The auxiliary control type thrust bearing 9 is provided for prevention of a fall. That is, when the rotator 1 cannot be kept floating by the levitation magnetic bearing 6 and the rotator 1 is about to fall, the levitation force due to the pinning effect does not increase much even if the displacement of the rotator 1 becomes large. So I can't stop this. Then, the auxiliary control type thrust bearing 9 operates. In this case, since the repulsive force increases as the expanded diameter portion 15 approaches the electromagnet 16, the fall can be suppressed.

In the present invention, the magnetic bearing 6 for levitation
Are formed in multiple stages in the axial direction of the outer rotor, it is easy to increase the number of permanent magnets 10 to increase the area facing the superconductor 11, and the diameter of the permanent magnets 10 does not change. There is no need to worry about the increase. In addition, the ring-shaped member made of the permanent magnet 10 is standardized, which facilitates manufacturing. In this way, a large levitation force can be obtained even with a small-diameter permanent magnet, so that it is possible to increase the size and weight for increasing the storage capacity.

Further, since the levitation magnetic bearing 6 and the radial control magnetic bearing 7 are arranged so as to overlap each other in the axial direction, the axial length is shortened. Therefore, the rotation is stable and the critical speed can be increased. Therefore, speedup is possible,
The efficiency of power storage is improved.

For reference, an example of the size of a flywheel for power storage is shown. The outer rotor has a shaft length of 6 m, the outer ring portion has a diameter of 6 m, the total weight of the rotating body is 100 tons, and the outer ring portion is 70 tons. Is. Maximum speed is 5 per minute
It is 000 rotations. The capacity is 10 MWh.

[0031]

The present invention exhibits the following excellent effects.

(1) Since a large levitation force can be obtained, it is possible to increase the size and weight of the rotating device, and since it can be made up of a small-diameter permanent magnet, the speed can be increased.

(2) The permanent magnets are uniformized and the manufacture is easy.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a power storage flywheel that uses a superconducting bearing according to an embodiment of the present invention.

FIG. 2 is a partially enlarged cross-sectional view of a magnetic bearing for levitation, which is a superconducting bearing of the present invention.

FIG. 3 is a perspective view of a superconductor pellet.

FIG. 4 is a cross-sectional view of a power storage flywheel showing a conventional example.

[Explanation of symbols]

 2 Fixed shaft 3 Outer ring part 5 Outer rotor 6 Magnetic bearing for levitation 10 Permanent magnet 11 Superconductor

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiromasa Higasa 2109 Yashima Nishimachi, Takamatsu City, Kagawa 8 Shikoku Research Institute Ltd.

Claims (4)

[Claims] 1. A superconducting bearing that supports a thrust load of a rotating device that fixes any one of a shaft member and an outer member that surrounds the outer periphery of the shaft member and rotates the other member. A superconducting bearing for rotating equipment, characterized in that superposed conductors are arranged facing the above-mentioned permanent magnets on the stacked and fixed members to support a thrust load by a pinning effect. 2. A hollow outer rotor is erected inside a rotating outer ring part, permanent magnets are superposed axially in multiple stages along the inner circumference of the outer rotor, and the outer circumference of a fixed shaft inserted into the outer rotor is described above. A flywheel for power storage, wherein a superconductor is arranged so as to face a permanent magnet, and the outer rotor is levitated by a pinning effect. 3. The power storage device according to claim 2, wherein the superconductor is cooled to a critical temperature at which a pinning effect is generated after the outer rotor is previously positioned at a predetermined axial position. Flywheel. 4. The flywheel for electric power storage according to claim 2, wherein an electromagnet forming a radial control magnetic bearing and an electromagnet forming a thrust control magnetic bearing are arranged on the outer periphery of the outer rotor.