JPH08219158A - Magnetic bearing device - Google Patents

Abstract

(57) [Abstract] [Purpose] First to construct magnetic bearings 19, 20, 29
The fourth permanent magnets 15, 21, 22, 27 are prevented from being destroyed by centrifugal force. [Configuration] The weight of the rotary shaft 2 and the flywheel 10 is
Superconducting magnetic bearing 19 and first and second passive magnetic bearings 2
It is supported by 0 and 29. Each magnetic bearing 19, 20, 2
The first to fourth permanent magnets 15, 21, 22,
Of the 27, the first and second permanent magnets 15 and 21 fixed to the flywheel 10 are provided inwardly in the diametrical direction. Thereby, the centrifugal force applied to the permanent magnets 15 and 21 is suppressed to be small. Or the flywheel 10 and the rotary shaft 2
A circular recess concentric with is formed, and a permanent magnet is arranged on the inner peripheral surface of this circular recess. By suppressing the outer peripheral surface of the permanent magnet with this inner peripheral surface, it is possible to prevent tensile stress from being applied to the permanent magnet regardless of the centrifugal force.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The magnetic bearing device according to the present invention comprises:
For example, a state in which surplus power at night is converted into kinetic energy and stored, and during the daytime this kinetic energy is converted into electric energy and is taken out to form an electric power storage device, such as a superconducting flywheel device, etc. Used in.

[0002]

2. Description of the Related Art A flywheel with a large moment is fixed to a rotary shaft as a device which can be installed in a small-scale business office or a general household to store surplus power at night, and a motor also serving as a generator is attached to the rotary shaft. Power storage devices are being researched. In the case of this power storage device, by supplying surplus power to the generator / motor at night, the rotary shaft and the flywheel are rotated, the surplus power is converted into kinetic energy, and the rotary motion of the flywheel is performed. Store as energy. Then, during the daytime, based on this rotational kinetic energy, the electric generator / motor is used to generate electric power, and the electric power is taken out and used.

In order to improve the efficiency of a power storage device using such a flywheel, a bearing device for rotatably supporting the flywheel is used which has a low rotational resistance and a low energy required for operation. There is a need to. Therefore, a power storage device using a superconducting magnetic bearing device as a bearing device has been conventionally proposed as described in Japanese Patent Laid-Open No. 5-248437. FIG.
Shows a power storage device incorporating the superconducting magnetic bearing device described in this publication.

A rotary shaft 2 is arranged vertically in the central portion of a vacuum housing 1 which is hermetically sealed. A holding cylinder 3 is fixed inside the vacuum housing 1 so as to surround the rotary shaft 2. Then, active magnetic bearings 6, 6 composed of magnetic rings 4, 4 and electromagnets 5, 5 are provided between the inner peripheral surface of the lower half of the holding cylinder 3 and the outer peripheral surface of the intermediate portion of the rotary shaft 2, respectively. The rotary shaft 2 is provided so as to be positioned in the radial direction. A rotor 7 is provided between the inner peripheral surface of the upper half of the holding cylinder 3 and the upper end of the rotary shaft 2.
A generator-combined motor 9 including a stator 8 and a stator 8 is provided.

A flywheel 10, which is a rotating member, is fixed to the lower end of the rotary shaft 2, and an annular permanent magnet 11 is fixed to the lower surface of the flywheel 10.
The permanent magnet 11 is magnetized in the axial direction (vertical direction in FIG. 8) and is fixed concentrically with the rotary shaft 2 which is the rotation center of the flywheel 10. Furthermore,
A cooling jacket 12, which also serves as a fixing member, is fixed to the bottom surface of the vacuum housing 1, and the upper surface of a superconductor 13 provided on the upper surface of the cooling jacket 12 is connected to the permanent magnet 11
Facing the underside of. It is desirable that the superconductor 13 has an annular shape similar to the permanent magnet 11 and is arranged concentrically with the permanent magnet 11. However, if it is difficult to make the annular shape, a plurality of superconductors each made of a disk shape, an arc shape, or the like are arranged at equal intervals on an arc concentric with the permanent magnet 11. A coolant such as liquid nitrogen is allowed to flow freely in the cooling jacket 12 so that the superconductor 13 can be brought into a superconducting state. Superconductor 13
Is superconducting, the pinning effect prevents the distance between the superconductor 13 and the permanent magnet 11 from changing. Therefore, the superconductor 13 and the permanent magnet 11 form a non-contact type superconducting thrust magnetic bearing 14.

The operation of the conventional power storage device constructed as described above is as follows. When the surplus power is stored at night, etc., by supplying the surplus power to the stator 8 of the generator / motor 9, the rotary shaft 2 and the flywheel 10 are provided.
To rotate. At this time, by the active magnetic bearing 6,
Positioning of the rotating shaft 2 in the radial direction
A coolant is sent into the cooling jacket 12 to cool the superconductor 13. When the superconductor 13 is cooled and becomes in the superconducting state, the magnetic flux emitted from the permanent magnet 11 is transferred to the superconductor 1.
Due to the so-called pinning effect, which is constrained within 3, the force that prevents the permanent magnet 11 from moving in the axial and radial directions with respect to the superconductor 13 acts. By this force, thrust force and radial force acting on the rotary shaft 2 and the flywheel 10 are supported. In this way, with the active magnetic bearing 6 and the superconducting thrust magnetic bearing 14 functioning, the rotary shaft 2 and the flywheel 1 are
0 is supported in a floating state. Therefore, the resistance against the rotation of these two members 2 and 10 is extremely small.

Since the rotational speeds of the rotary shaft 2 and the flywheel 10 gradually increase with the energization of the stator 8, the electric power can be stored in the state of being converted into mechanical kinetic energy. Since the rotating shaft 2 and the flywheel 10 are provided in the vacuum housing 1, the surface of the rotating member and the air do not rub against each other, and once the rotating speed of the flywheel 10 rises, the rotating speed of the generator is increased. Unless the electric power is taken out by the dual-purpose motor 9, there is almost no decrease. When the stored energy is taken out and used in the daytime, the stator 8 is connected to a load (electric equipment). As a result, electric power is generated in the stator 8 based on the rotational movement of the flywheel 10.

Although not shown, the non-contact type radial bearing for preventing the radial displacement of the rotary shaft 2 may be a superconducting magnetic bearing. In this case,
The magnetic rings 4, 4 are provided on the outer peripheral surface of the intermediate portion of the rotating shaft 2.
In place of the electromagnets 5 and 5, a superconductor is fixed to the inner peripheral surface of the lower half of the holding cylinder 3 while fixing a diametrically or axially magnetized annular permanent magnet.
A cooling jacket for cooling the superconductor is provided inside the holding cylinder 3.

[0009]

By the way, for example, when the weight of the flywheel 10 is made large (heavy) in order to improve the electric power storage capacity of the electric power storage device configured and operated as described above, the superconducting thrust is increased. Magnetic bearing 1
It is necessary to increase the load capacity of No. 4. Also, when supporting a large thrust load applied to the rotary shaft of various mechanical devices, a large load capacity is still required. However,
At present, there is a limit to the load capacity of the superconducting thrust magnetic bearing 14 that can be practically used, and the flywheel 10 that can be supported only by the superconducting thrust magnetic bearing 14 is used to improve the performance of the power storage device, or a large capacity is required. It was difficult to support the rotating shaft to which the thrust load is applied.

In order to compensate for such a lack of load capacity of the superconducting thrust magnetic bearing 14, the superconducting thrust magnetic bearing 14 is added between the lower surface of the rotating member such as the flywheel 10 and the upper surface of the fixed member such as the housing. It is also possible to incorporate a repulsive passive magnetic bearing. However, if a repulsive passive magnetic bearing is simply installed between the lower surface of the rotating member and the upper surface of the fixed member, the reliability and durability of the permanent magnets that make up this passive magnetic bearing must be ensured. Becomes difficult.

That is, in order to sufficiently support the weight of a rotating member such as a flywheel 10 having a large diameter in order to store a large amount of energy, and to allow the rotating member to rotate without wobbling, It is necessary to provide the permanent magnet that constitutes the repulsive passive magnetic bearing even on the lower surface outer peripheral portion of the rotating member. On the other hand, in order to store a large amount of energy, it is necessary to considerably increase the rotation speed of the rotary member. Therefore, it is unavoidable that a considerably large centrifugal force acts on the permanent magnet provided on the outer peripheral portion of the lower surface of the rotating member. The material forming the permanent magnet, such as ferrite, has a lower toughness than general metal materials such as steel, and is easily broken by the tensile stress based on the large centrifugal force. The magnetic bearing device of the present invention was invented in view of such circumstances.

[0012]

All of the magnetic bearing devices of the present invention are provided with a rotating member, a fixed member provided so as to face the rotating member, and between the rotating member and the fixed member. A superconducting magnetic bearing and first and second passive magnetic bearings are provided.

According to another aspect of the magnetic bearing device of the present invention, the superconducting magnetic bearing includes a first permanent magnet fixed to a portion of the rotary member near the center of rotation of the rotary member, and the fixed member. And a superconductor fixed to a portion facing the first permanent magnet. The first passive magnetic bearing is a second permanent magnet fixed to the lower surface of the rotary member and axially magnetized in an annular shape with the center of rotation of the rotary member as its center. An annular third axially magnetized permanent magnet fixed to a portion of the upper surface of the fixing member facing the lower surface of the second permanent magnet, the upper surface of the third permanent magnet and the second permanent magnet It is a repulsive passive magnetic bearing in which the lower surface of a permanent magnet and the same poles face each other. Further, the second passive magnetic bearing is fixed to a ferromagnetic body portion provided on a peripheral portion of an upper surface of the rotating member and a portion of the fixing member facing the upper surface of the ferromagnetic body portion. Is a suction-type passive magnetic bearing having a fourth permanent magnet.

On the other hand, in the magnetic bearing device according to the second aspect of the present invention, a circular recess concentric with the rotation center of the rotary member is formed on the lower surface of the rotary member, and the circular recess is formed on the upper surface of the fixed member. A circular convex portion that can be loosely inserted into the circular concave portion is formed in the matching portion. The superconducting magnetic bearing has a first permanent magnet fixed to the inner peripheral surface of the circular concave portion and a superconductor fixed to the outer peripheral surface of the circular convex portion and facing the inner peripheral surface of the first permanent magnet. With. The first passive magnetic bearing is a second permanent magnet that is fixed to the rear end surface of the circular recess and is axially magnetized in an annular shape with the center of rotation of the rotating member as its center.
An annular third axially magnetized permanent magnet fixed to a portion of the circular convex portion facing the lower surface of the second permanent magnet, the upper surface of the third permanent magnet and the above This is a repulsive passive magnetic bearing in which the lower surface of the second permanent magnet and the same pole face each other. Further, the second passive magnetic bearing is fixed to a ferromagnetic body portion provided on a peripheral portion of an upper surface of the rotating member and a portion of the fixing member facing the upper surface of the ferromagnetic body portion. Is a suction-type passive magnetic bearing having a fourth permanent magnet.

[0015]

According to the magnetic bearing device of the present invention configured as described above, a rotating member that is heavy can be stably supported. That is, since the weight of the rotating member is supported by both the superconducting magnetic bearing and the first and second passive magnetic bearings, the load capacity of the entire magnetic bearing device can be sufficiently secured. In addition, since the ferromagnetic portion forming the second passive magnetic bearing is provided on the outer peripheral portion of the upper surface of the rotating member, the rotating member can be stably supported without tilting. A large centrifugal force acts on the ferromagnetic part as the rotary member rotates, but since the ferromagnetic part can be made of a material having great toughness such as steel, the rotary member was rotated at a high speed. Even in this case, this ferromagnetic part is not destroyed.

Further, both the first permanent magnet constituting the superconducting magnetic bearing and the second, third and fourth permanent magnets constituting the first and second passive type magnetic bearings have centrifugal force generated by the rotation of the rotary member. Will not be destroyed by. That is, in any structure, since the third and fourth permanent magnets are fixed to the fixing member side and do not rotate, no centrifugal force is applied. Further, in any of the structures, the second permanent magnet can be installed in a portion relatively close to the center of rotation, so that the centrifugal force applied to the second permanent magnet due to the rotation of the rotating member is limited. Therefore, the second permanent magnet is less likely to be destroyed by the centrifugal force.

Further, the remaining first permanent magnet is not destroyed by the centrifugal force for the following reason. First, in the case of the structure described in claim 1, since the first permanent magnet is fixed to a portion of the rotating member near the center of rotation, the centrifugal force applied to the first permanent magnet as the rotating member rotates. Is limited, and the first permanent magnet is less likely to be destroyed by centrifugal force. On the other hand, in the case of the structure described in claim 2,
Since the outer peripheral surface of the first permanent magnet fixed to the inner peripheral surface of the circular recess is held down by the inner peripheral surface of the circular recess, even if centrifugal force is applied to this first permanent magnet, No large tensile stress is applied to the magnet. Therefore, the first permanent magnet is not destroyed by the centrifugal force.

[0018]

FIG. 1 shows a first embodiment of the present invention corresponding to claim 1. At the lower end of the rotary shaft 2, a flywheel 10 that constitutes a rotary member together with the rotary shaft 2 is fixed concentrically with the rotary shaft 2. A first permanent magnet 15 is fixed to the center of the lower surface of the flywheel 10. Each of the first permanent magnets 15 has an axial direction (see FIG.
(In the up and down direction of FIG. 2) and is arranged concentrically with the rotary shaft 2 in the form of a columnar magnet element 15a and an annular magnet element 15.
b. In addition, around the flywheel 10,
It is surrounded by a housing 16 which is a fixing member. The rotary shaft 2 is projected to the outside of the housing 16 through a circular hole 17 provided in the central upper portion of the housing 16. A disc-shaped superconductor 18 is fixed to the upper surface of the central portion of such a housing 16, and the upper surface of the superconductor 18 and the lower surface of the first permanent magnet 15 are opposed to each other. The superconductor 18 and the first permanent magnet 15 constitute a superconducting magnetic bearing 19, and the superconducting magnetic bearing 19 is the superconductor 1.
The pinning effect of 8 functions to keep the distance between the flywheel 10 and the housing 16 constant. Although not shown, a cooling jacket is provided in the housing 16 so that the superconductor 18 can be cooled to a temperature at which it is in a superconducting state.

Further, around the superconducting magnetic bearing 19,
A first passive magnetic bearing 20 is provided. The first passive magnetic bearing 20 includes a second permanent magnet 21 and a third permanent magnet 22, each of which has an annular shape. Each of the permanent magnets 21 and 22 is magnetized in the axial direction and arranged concentrically with the rotary shaft 2, and a plurality (four in the illustrated example) of annular magnet elements 21a, 22a. The second permanent magnet 21 among them is fixed to the peripheral portion of the first permanent magnet 15 on the lower surface of the flywheel 10. That is, the first permanent magnet 1 is formed in the circular recess 23 formed in the center of the lower surface of the flywheel 10.
5, the magnet elements 15a and 15b constituting the second permanent magnet 21 and the magnet elements 21a and 21a constituting the second permanent magnet 21 are concentrically fitted to each other, and the magnet elements 15a adjacent to each other in the diametrical direction (left and right direction in FIG. 1), Annular spacers 24, 24 made of a non-magnetic material such as synthetic resin or aluminum alloy are sandwiched between the peripheral surfaces of 15b, 21a.

On the other hand, the magnet elements 22a, 22a constituting the third permanent magnet 22 are fixed to the peripheral portion of the superconductor 18 on the upper surface of the housing 16. That is,
An annular recess 25 formed on the upper surface of the housing 16
The magnet elements 22a, 22a are arranged concentrically with each other, and non-magnetic material annular spacers 24, 24 are sandwiched between the circumferential surfaces of the magnet elements 22a, 22a adjacent in the diametrical direction. Each of these magnet elements 22a, 22a is also magnetized in the axial direction. The upper surfaces of the magnet elements 22a, 22a forming the third permanent magnet 22 and the lower surfaces of the magnet elements 21a, 21a forming the second permanent magnet 21 face each other with the same poles. Therefore, the second and third permanent magnets 21 and 22 constitute a repulsive passive magnetic bearing, and the rotary shaft 2 and the flywheel 10 are
Part of the weight of is freely supported.

Further, an annular plate 26 made of a ferromagnetic material such as a steel plate is fixed to a portion extending from the middle of the upper surface of the flywheel 10 toward the outer periphery, and the portion near the outer periphery of the upper surface serves as a ferromagnetic material portion. There is. And the housing 16
The fourth permanent magnet 27 is fixed to the lower surface of the plate, and the lower surface of the fourth permanent magnet 27 and the upper surface of the plate 26 are opposed to each other,
It constitutes the second passive magnetic bearing 29. To fix the fourth permanent magnet 27, an annular recess 28 is formed on the lower surface of the housing 16. In addition, annular magnet elements 27a, 27a forming the fourth permanent magnet 27 are concentrically arranged in the recess 28, and the magnet elements 27a, 27a that are diametrically adjacent to each other are not arranged between the circumferential surfaces. An annular spacer 24 made of a magnetic material is sandwiched. Each of these magnet elements 27a, 27a is also magnetized in the axial direction.

The magnetic bearing device of the present invention comprises the superconducting magnetic bearing 19 and the first and second passive magnetic bearings 20 and 29, each of which is constructed as described above. It is assumed that the total load capacity of the passive magnetic bearings 20 and 29 can support the weight of the rotary shaft 2 and the flywheel 10 or is slightly insufficient to support the weight. And
When the load capacities of these passive magnetic bearings 20 and 29 and the load capacity of the superconducting magnetic bearing 19 are summed up, the weight of the rotary shaft 2 and the flywheel 10 (including the weight of permanent magnets fixed to these) is included. ) Is sufficient to support the above, and the load capacity of each magnetic bearing 19, 20, 29 is adjusted so that the rotating shaft 2 and the flywheel 10 do not move up and down.

That is, the first passive magnetic bearing 20 which is the repulsive passive magnetic bearing and the second passive magnetic bearing 29 which is the suction passive magnetic bearing are both the rotary shaft 2 and the fly. Only the upward force is applied to the wheel 10. On the other hand, in the superconducting magnetic bearing 19, by pinning the magnetic flux emitted from the first permanent magnet 15 in the superconductor 18,
It is a resistance against both the ascent and descent of the rotary shaft 2 and the flywheel 10. The magnetic bearing device of the present invention has the magnetic bearings 19 and 2 having different properties as described above.
0, 29 are combined and each magnetic bearing 19, 20, 2
Since the load capacity of 9 is adjusted, the rotary shaft 2 and the flywheel 10 can be kept in the floating state (without being lowered or raised).

When the magnetic bearing device of the present invention having the above-described structure is operated, for example, the superconductor 18 is not cooled, and the superconductor 18 is raised to the rotary shaft 2 while maintaining the normal conduction state. A force is applied in the direction to raise the flywheel 10 slightly. Then, the superconductor 18 is cooled,
After the superconductor 18 is put into a superconducting state, the rotating shaft 2
The lifting force that was applied to is released. As a result, while the rotary shaft 2 and the flywheel 10 are slightly lowered due to their weight, the rotary shaft 2 and the flywheel 10 are connected to the first superconductor 18 based on the pinning force of the superconductor 18. The floating state is supported by the force acting between the permanent magnet 15 and the permanent magnet 15.

The force for supporting the rotating shaft 2 and the flywheel 10 in a floating state as described above can also be obtained by the first and second passive magnetic bearings 20 and 29. Therefore, the load capacity of the magnetic bearing device as a whole can be sufficiently secured, and the flywheel 10 which is heavy can be supported. or,
Since the plate 26, which is a ferromagnetic material portion that constitutes the second passive magnetic bearing 29, is provided up to the outer peripheral edge of the upper surface of the flywheel 10, the flywheel 10 and the rotary shaft 2 are stable without tilting. You can support it. A large centrifugal force acts on the plate 26 as the flywheel 10 rotates, but since the plate 26 can be made of a material having a large toughness such as steel, when the flywheel 10 is rotated at a high speed. However, the plate 26 is not destroyed.

The magnet elements 15a and 15b of the first permanent magnet 15 constituting the superconducting magnetic bearing 19 are also the second, third and fourth permanent magnets constituting the first and second passive magnetic bearings 20 and 29. The magnet elements 21a, 22a of the magnets 21, 22, 27,
27a is also not destroyed by the centrifugal force generated by the rotation of the flywheel 10. That is, the third and fourth permanent magnets 2
Since the magnet elements 22a, 27a of 2, 27 are fixed to the housing 16 side and do not rotate, they are not subjected to centrifugal force at all. Also, the magnet elements 21a, 21a of the second permanent magnet 21.
Is installed in a portion of the lower surface of the flywheel 10 that is relatively close to the center of rotation.
The centrifugal force applied to each of the magnet elements 21a, 21a due to the rotation of is limited. Therefore, these magnet elements 21a, 21a are less likely to be destroyed by the centrifugal force.

Furthermore, since the remaining first permanent magnet 15 is also fixed to the center of rotation of the flywheel 10, the centrifugal force applied to the magnet elements 15a and 15b of the first permanent magnet 15 as the flywheel 10 rotates. The force is limited, and the magnet elements 15a and 15b are less likely to be destroyed by the centrifugal force. As a result, the magnetic bearing device of the present invention has a sufficient load capacity and can secure sufficient reliability and durability even when rotated at a high speed. In particular, as shown, each magnet element 15a, 15b, 21a, 2
In the structure in which 1a is housed in the recess 23, each magnet element 15
Since the outer peripheral surfaces of a, 15b, 21a, and 21a can be suppressed, these magnet elements 15a, 15b, 21a, and 21a can be suppressed.
The damage prevention effect of can be further increased.

Next, FIG. 2 shows a second embodiment of the present invention, which also corresponds to claim 1. In the case of the present embodiment, the magnetic field formed by the first to fourth permanent magnets 15, 21, 22, 27 constituting the magnetic bearings 19, 20, 29 is strengthened, so that the load capacity of the magnetic bearing device is increased. Is getting bigger. Therefore, in this embodiment, the following structure is used.
The magnetic field of each of the permanent magnets 15, 21, 22, 27 is strengthened.

First, the magnetizing directions of the magnet elements 15a and 15b constituting the first permanent magnet 15 are made opposite to each other, and
The upper end surfaces of both of the magnet elements 15a and 15b are abutted against the lower surface of a magnetically permeable plate 30 made of a ferromagnetic material such as a mild steel plate in a disk shape. As a result, both the magnet elements 15a, 1
The magnetic field formed between the lower end surfaces of 5b becomes strong (high-density magnetic flux flows), the load capacity of the superconducting magnetic bearing 19 increases, and the bearing rigidity improves.

Next, in the second and third permanent magnets 21 and 22 incorporated in the first passive magnetic bearing 20, four magnet elements 21a and 22a, which constitute each permanent magnet 21 and 22, respectively. And two pieces on the inner half side,
Each of the two parts on the outer peripheral side is combined. The magnetizing directions of the magnet elements 21a and 22a forming each set are opposite to each other. Further, the magnetizing directions of the two magnet elements 21a and 22a, which are intermediate portions (belonging to different groups and adjacent to each other), are the same. Then, the upper end surfaces of the magnet elements 21a, 21a belonging to the same set and the lower end surfaces of the magnet elements 22a, 22a are abutted against the magnetically permeable rings 31, 31 made of a ferromagnetic material, respectively. As a result, the magnetic field formed between the facing surfaces of the magnet elements 21a and 22a becomes stronger, the load capacity of the first passive magnetic bearing 20 increases, and the bearing rigidity improves.

Further, in the fourth permanent magnet 27 incorporated in the second passive magnetic bearing 29, the six permanent magnets 27a, 27a constituting the fourth permanent magnet 27 are set as two adjacent pairs. The magnet elements 27a, 27a forming each group are divided into three groups, and the magnetizing directions thereof are opposite to each other.
In addition, magnet elements 27a belonging to different groups and adjacent to each other,
The magnetizing directions of 27a are the same. Then, the upper end surfaces of the magnet elements 27a, 27a belonging to the same set are abutted against the magnetically permeable rings 31, 31 made of a ferromagnetic material, respectively. In addition, a plurality of recesses are formed in a portion of the upper surface of the plate 26 facing the lower surface of the fourth permanent magnet 27, which faces the lower end surface of the spacer 24 sandwiched between the peripheral surfaces of the adjacent magnet elements 27a and 27b. The grooves 32, 32 are formed over the entire circumference.

As a result of such a configuration, each of the above-mentioned magnet elements 2
A strong magnetic field is formed between the lower end surfaces of 7a and 27a and the convex portions located between the adjacent concave grooves 32 and 32 on the upper surface of the plate 26, and the load capacity of the second passive magnetic bearing 29 is reduced. The bearing rigidity increases with the increase. Further, due to the strong magnetic field formed between the lower end surfaces of the magnet elements 27a, 27a and the convex portions, a strong attractive force acts between the lower end surfaces and the convex portions. Therefore, the fourth permanent magnet 2
Even if the 7 and the plate 26 tend to shift in the diametrical direction, the suction force acts in a direction to correct this deviation.
Therefore, in the case of this embodiment, not only the superconducting magnetic bearing 19 but also the second passive magnetic bearing 29 has a function of correcting the displacement in the diametrical direction, and the radial rigidity of the entire magnetic bearing device is improved. . Other configurations and operations are similar to those of the first embodiment described above.

Next, FIG. 3 shows a third embodiment of the present invention, which also corresponds to claim 1. In the case of this embodiment, the superconducting radial magnetic bearing 33 is provided between the outer peripheral surface of the rotary shaft 2 and the inner peripheral surface of the circular hole 17 formed in the housing 16.
Is provided. That is, the outer peripheral surface of the rotary shaft 2 is provided with a fifth permanent magnet 34 including a plurality of magnet elements 34a, 34a, each of which is magnetized in the axial direction (which may be different from the case shown in the drawing and may be the radial direction). . In the illustrated example, the magnetizing directions of the magnet elements 34a, 34a are the same,
The magnetizing directions may be reversed between the adjacent magnet elements 34a, 34a. Then, the cylindrical superconductor 35 is fixed to the inner peripheral surface of the circular hole 17, and the inner peripheral surface of the superconductor 35 and the outer peripheral surface of the fifth permanent magnet 34 are opposed to each other. The superconductor 35 is brought into a superconducting state by sending a coolant such as liquid nitrogen into a cooling jacket (not shown) provided in the housing 16. Then, by pinning the magnetic flux emitted from the fifth permanent magnet 34 inside, the rotational shaft 2 is prevented from being displaced in the radial direction. In the case of this embodiment, the radial rigidity of the magnetic bearing device as a whole is further improved as compared with the second embodiment. Since the diameter of the fifth permanent magnet 34 is small and the centrifugal force acting on the fifth permanent magnet 34 is small, the fifth permanent magnet 34 is not destroyed by the centrifugal force. Other configurations and operations are similar to those of the second embodiment described above. The superconducting radial magnetic bearing 33 is also an aspect of the superconducting magnetic bearing described in claim 1.

Next, FIG. 4 shows a fourth embodiment of the present invention, which also corresponds to claim 1. In the case of the present embodiment, the lower end of the rotary shaft 2 is made to project below the lower surface of the flywheel 10, and this lower end is loosely inserted into the circular recess 36 formed inside the housing 16. A superconducting radial magnetic bearing 33A is also provided between the outer peripheral surface of the lower end and the inner peripheral surface of the circular recess 36. This superconducting radial magnetic bearing 33A is the superconducting magnetic bearing according to claim 1, and this superconducting radial magnetic bearing 3
The permanent magnet 34A constituting 3A corresponds to the first permanent magnet in claim 1. In the case of this embodiment, the upper and lower parts 2 of the rotary shaft 2
Since the superconducting radial magnetic bearings 33 and 33A are provided at the positions, the radial rigidity of the magnetic bearing device as a whole is
Further improvement over the third embodiment. Other configurations and operations are similar to those of the third embodiment described above.

Next, FIG. 5 shows a fifth embodiment of the present invention, which also corresponds to claim 1. In the case of the present embodiment, a cylindrical portion 37 is provided above the housing 16, and a plurality (three in the illustrated example) of a plurality of (three in the illustrated example) are provided between the inner peripheral surface of the cylindrical portion 37 and the outer peripheral surface of the rotary shaft 2. Controlled magnetic bearings 38, 38 are provided. Therefore, in the case of this embodiment, cylindrical rotors 39, 39 made of a ferromagnetic material such as steel are fixed at three positions on the outer peripheral surface of the rotary shaft 2. Further, electromagnets 40, 40 are fixed to the portions of the inner surface of the cylindrical portion 37 facing the rotors 39, 39 at three positions.
Each of these electromagnets 40, 40 is composed of an electromagnet element divided into four in the circumferential direction, and by energizing any one of the electromagnet elements based on a signal from a displacement sensor (not shown), the radial direction of the rotary shaft 2 described above. Regulate position. In the case of the present embodiment, by providing the control type magnetic bearings 38 having a large radial rigidity, the radial rigidity of the entire magnetic bearing device is improved. Other configurations and operations are similar to those of the first embodiment described above.

Next, FIG. 6 shows a sixth embodiment of the present invention, which corresponds to the second aspect. A circular recess 41 concentric with the rotary shaft 2 is formed on the lower surface of the flywheel 10, and a portion of the upper surface of the housing 16 aligned with the circular recess 41 is a circular shape that can be loosely inserted into the circular recess 41. The convex portion 42 is formed. And the superconducting magnetic bearing 1
9a, the first permanent magnet 15A, the circular recess 4
It is fixed to the inner peripheral surface of 1. A cylindrical superconductor 18a which also constitutes the superconducting magnetic bearing 19a is fixed to the outer peripheral surface of the circular convex portion 42. The superconducting magnetic bearing 19a has a function of bearing a radial load acting between the flywheel 10 and the housing 16 and also a function of bearing a thrust load.

The second permanent magnet 21 constituting the first passive magnetic bearing 20 is fixed to the inner end surface of the circular recess 41. That is, the circular concave portion 43 formed on the rear end surface
In addition, the columnar magnet element 21b and the annular magnet elements 21a, 21a forming the second permanent magnet 21 are arranged concentrically with the rotary shaft 2. On the other hand, the circular convex portion 42
The third permanent magnet 22 is fixed to a portion of the end surface of the second permanent magnet 21 facing the lower surface of the second permanent magnet 21. That is, in the circular concave portion 44 formed on the end face of the circular convex portion 42, the columnar magnet element 22b and the annular magnet elements 22a, 22a constituting the third permanent magnet 22 are connected to the rotary shaft 2. They are arranged concentrically. Then, the upper end surfaces of the magnet elements 22a, 22b forming the third permanent magnet 22 and the lower end surfaces of the magnet elements 21a, 21b forming the second permanent magnet 21 are made to face each other with the same pole, and the repulsion type It constitutes a passive magnetic bearing. The upper end surfaces of the magnetic elements 21a and 21b and the lower end surfaces of the magnetic elements 22a and 22b are abutted against the magnetically permeable plates 30 and 30 or the magnetically permeable rings 31 and 31, respectively.
The load capacity and the bearing rigidity of the first passive magnetic bearing 20 are increased. The structure and operation of the second passive magnetic bearing 29 are similar to those of the second to fourth embodiments. It is assumed that the total load capacity of the first and second passive magnetic bearings 20 and 29 can support the weight of the rotary shaft 2 and the flywheel 10 or is slightly insufficient to support them. When the load capacity of the bearings 20, 29 and the load capacity of the superconducting magnetic bearing 19a are summed up, it becomes sufficient to support the weight of the rotary shaft 2 and the flywheel 10,
Moreover, adjusting the load capacity of each magnetic bearing 19a, 20, 29 so that the rotary shaft 2 and the flywheel 10 do not move up and down is the same as in each of the above-described embodiments.

In the case of this embodiment constructed as described above, the circular recess 41 is formed in order to form the superconducting magnetic bearing 19a.
The outer peripheral surface of the first permanent magnet 15A fixed to the inner peripheral surface of
Since it is suppressed by the inner peripheral surface of the circular recess 41, even if a centrifugal force is applied to the first permanent magnet 15A, a large tensile stress is not applied to the first permanent magnet 15A. Therefore, the first permanent magnet 15A is not destroyed by the centrifugal force. Other functions are similar to those of the second embodiment described above.

Next, FIG. 7 shows a seventh embodiment of the present invention, which also corresponds to claim 2. In the case of this embodiment, the superconducting radial magnetic bearing 33 is provided between the outer peripheral surface of the rotary shaft 2 and the inner peripheral surface of the circular hole 17 formed in the housing 16.
Is provided. The structure and operation of the superconducting radial magnetic bearing 33 are the same as those of the superconducting radial magnetic bearing 33 (FIG. 3) incorporated in the third embodiment described above.
Other configurations and operations are similar to those of the sixth embodiment described above. The present embodiment also belongs to the technical scope of the invention described in claim 1.

[0040]

Since the magnetic bearing device of the present invention is constructed and operates as described above, it is possible not only to secure a sufficiently large load capacity and to support a large load applied to the rotating portion but also to apply a centrifugal force to the magnetic bearing device. Since it is possible to prevent the permanent magnet from being damaged, it is possible to secure sufficient reliability and durability.

[Brief description of drawings]

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

FIG. 2 is a sectional view showing the second embodiment.

FIG. 3 is a sectional view showing the third embodiment.

FIG. 4 is a sectional view showing the fourth embodiment.

FIG. 5 is a sectional view showing the fifth embodiment.

FIG. 6 is a sectional view showing the sixth embodiment.

FIG. 7 is a sectional view showing the seventh embodiment.

FIG. 8 is a longitudinal sectional view showing a power storage device incorporating a conventionally known superconducting magnetic bearing device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vacuum housing 2 Rotating shaft 3 Holding cylinder 4 Magnetic ring 5 Electromagnet 6 Active magnetic bearing 7 Rotor 8 Stator 9 Generator / motor 10 Flywheel 11 Permanent magnet 12 Cooling jacket 13 Superconductor 14 Superconducting thrust magnetic bearing 15, 15A 1st Permanent magnet 15a, 15b Magnet element 16 Housing 17 Circular hole 18, 18a Superconductor 19, 19a Superconducting magnetic bearing 20 First passive magnetic bearing 21 Second permanent magnet 21a, 21b Magnet element 22 Third permanent magnet 22a, 22b Magnet Element 23 Recess 24 Spacer 25 Recess 26 Plate 27 Fourth permanent magnet 27a Magnet element 28 Recess 29 Second passive magnetic bearing 30 Permeable plate 31 Permeable ring 32 Recessed groove 33, 33A Superconducting radial magnetic bearing 34 Fifth permanent magnet 34a Magnet element 34A Permanent magnet Stone 35 Superconductor 36 Circular concave portion 37 Cylindrical portion 38 Controlled magnetic bearing 39 Rotor 40 Electromagnet 41 Circular concave portion 42 Circular convex portion 43, 44 concave portion

Claims (2)

[Claims] 1. A rotary member, a fixed member provided to face the rotary member, a superconducting magnetic bearing and first and second passive magnetic bearings provided between the rotary member and the fixed member. The superconducting magnetic bearing among these, the first permanent magnet fixed to a portion of the rotating member near the center of rotation of the rotating member, and the first permanent magnet with a portion of the fixed member. A superconducting member fixed to the facing portion, wherein the first passive magnetic bearing is fixed to the lower surface of the rotating member and has an annular shape with the center of rotation of the rotating member as its center in the axial direction. A second permanent magnet that is magnetized, and a third permanent magnet that is fixed to a portion of the upper surface of the fixing member that faces the lower surface of the second permanent magnet and is annularly magnetized in the axial direction, The upper surface of the third permanent magnet and the lower surface of the second permanent magnet have the same polarity. Is a repulsive passive magnetic bearing opposed to each other by the second passive magnetic bearing, and the second passive magnetic bearing is composed of a ferromagnetic portion provided in a portion near the outer periphery of the upper surface of the rotating member and a part of the fixed member. A magnetic bearing device, which is a suction-type passive magnetic bearing, including a fourth permanent magnet fixed to a portion facing the upper surface of the ferromagnetic body portion. 2. A rotary member, a fixed member provided to face the rotary member, a superconducting magnetic bearing and first and second passive magnetic bearings provided between the rotary member and the fixed member. And a circular recess concentric with the center of rotation of the rotary member is formed on the lower surface of the rotary member, and a portion of the upper surface of the fixed member that is aligned with the circular recess loosely fits in the circular recess. An insertable circular convex portion is formed, and the superconducting magnetic bearing has the first permanent magnet fixed to the inner peripheral surface of the circular concave portion and the first permanent magnet fixed to the outer peripheral surface of the circular convex portion. The first passive magnetic bearing comprises an inner peripheral surface of a magnet and a superconductor facing the inner peripheral surface of the magnet, and the first passive magnetic bearing is an annular shaft fixed to the inner end surface of the circular recess and having the center of rotation of the rotating member as its center. Direction permanent magnets and the end face of the circular protrusion And an annular third axially magnetized permanent magnet fixed to a portion facing the lower surface of the second permanent magnet, and the upper surface of the third permanent magnet and the lower surface of the second permanent magnet. Is a repulsive passive magnetic bearing in which the same poles are opposed to each other, and the second passive magnetic bearing is a ferromagnetic member provided in a portion near the outer periphery of the upper surface of the rotating member, and the fixed member. A magnetic bearing device which is a suction-type passive magnetic bearing including a fourth permanent magnet fixed to a part of the ferromagnetic part facing the upper surface of the ferromagnetic part.