JPH0798017A - Magnetic bearing device - Google Patents

Abstract

PURPOSE:To provide a magnetic bearing device which has a rotational body having short axial length, high bending characteristic frequency, and uses superconducting material for reducing weight of the rotational body. CONSTITUTION:In a magnetic bearing device, superconductors 7 are fixed to a rotational body, and a rotary shaft is supported by pinning effect and Meissner effect under a non-contact condition. The rotational body is composed of a stator 10 having a primary coil of a rotary driving motor and the superconductors 7 arranged opposingly to the stator 10 via a gap. Number of the superconductors 7 corresponds to number of poles of spatial moving magnetic field formed by the primary coil of the motor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic bearing device, and more particularly to a magnetic bearing device using a superconducting material which does not require a sensor for detecting axial displacement and does not require axial control of a rotary shaft.

[0002]

2. Description of the Related Art In FIG. 8, a superconducting material is fixed to a rotating body,
2 shows a rotating system supported by a magnetic bearing device that supports a rotating shaft in a non-contact manner by a pinning effect and a Meissner effect. A rotary body 2 such as an impeller is fixed to the rotary shaft 1 and is rotated by a motor 3. The rotating shaft 1 is supported by an upper first magnetic bearing device 4 and a lower second magnetic bearing device 5. In the magnetic bearing devices 4 and 5, the permanent magnet 6 is fixed to the rotating shaft 1, the superconducting bulk material 7 is fixed to the stator side, and the permanent magnet 6 and the superconducting bulk material 7 are arranged to face each other. ing. Due to the pinning effect and the Meissner effect of the superconducting bulk material 7, the rotary shaft 1 is supported in the axial direction and the radial direction without contact.

[0003]

However, in the conventional magnetic bearing device, the superconducting magnetic bearings 4 and 5 and the motor 3 are separately installed as shown in FIG. However, there is a problem that the axial length of the rotating body becomes long, the bending natural frequency of the rotating body decreases, and the weight of the rotating body becomes large.

The present invention has been made in view of the above-mentioned problems of the prior art. The axial length of the rotating body is short, the bending natural frequency of the rotating body is high, and the weight of the rotating body is small. The present invention provides a magnetic bearing device using a superconducting material that can be manufactured.

[0005]

SUMMARY OF THE INVENTION A magnetic bearing device of the present invention is a magnetic bearing device in which a superconductor is fixed to a rotating body and a rotating shaft is supported in a contacted manner by a pinning effect and a Meissner effect. A stator having a primary coil of a motor, and a rotating body having a superconductor arranged so as to face the stator through a gap,
The number of the superconductors is arranged according to the number of poles of the space moving magnetic field formed by the primary coil of the motor.

[0006]

The superconductor provided in the rotating body is arranged so as to face the same number of poles of the space moving magnetic field formed by the primary coil of the motor, so that the Meissner effect and pinning effect of the superconductor can be achieved. Thus, the superconductor is pinned to the space moving magnetic field, rotates according to the space moving magnetic field, and is supported by the stator as a non-contact magnetic bearing.
Therefore, a magnetic bearing device that also serves as a magnetic bearing and a motor can be configured, a special member for the motor is not required, the length of the rotating shaft can be shortened, and the bending natural frequency of the rotating body can be increased, The weight of the rotating body can be reduced.

[0007]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1A is a cross-sectional view of a main part of a magnetic bearing device according to a first embodiment of the present invention along a radial direction,
FIG. 3B is a sectional view of a main part along the axial direction thereof.

In this embodiment, the primary coil of the motor and the superconductor 7 of the rotating body 1 like a radial magnetic bearing.
Are arranged so as to face each other in the radial direction via a gap G, and their axial positions are aligned. Stator 10
Is equipped with a primary coil of a rotation drive motor.
The space moving magnetic field formed by the primary coil of the stator has a magnetic flux density in the radial direction changed in the gap G in a sinusoidal shape along the circumferential direction. The strength of the space moving magnetic field changes according to the magnitude of the alternating current applied to the primary coil, and the rotation speed changes when the frequency of the alternating current changes. The space moving magnetic field in the gap G rotates in the circumferential direction along the gap G. The number of poles of the space moving magnetic field formed by the primary coil of the rotation driving motor arranged on the stator 10 is arranged according to the number of superconductors 7 arranged on the rotating body 1. That is, four superconductors 7 are arranged on the rotating body 1 side so as to match the four poles S, N, S, N of the space moving magnetic field formed on the stator side.

FIG. 2 is an explanatory view for explaining the operation of the magnetic bearing device shown in FIG. Due to the Meissner effect and the pinning effect of the superconductor 7, the superconductor 7 of the rotating body 1 is moved to the stator 1 by the magnetic field formed by the primary coil of the stator.
It is supported in a non-contact floating state from 0. When the north pole or the south pole of the space moving magnetic field faces the superconductor 7 and the magnetic flux penetrates into the superconductor, the superconductor 7 is pinned to the space moving magnetic field. By matching the polarity of the space-moving magnetic field and the pinning polarity of the superconductor in this way, in order to try to supplement the same magnetic flux density as the pinned magnetic flux density, the rotating magnetic field generated by the motor coil on the stator side is tracked. Then, the superconductor 7 also rotates, and the rotating body 1 rotates as a rotor. Further, by the same pinning effect, a rotating magnetic field having a magnetic flux density higher than the pinning magnetic flux density is generated from the stator side, so that the rigidity of the magnetic bearing can be increased. This magnetic bearing device has a structure similar to a radial magnetic bearing, but since the superconductor is pinned by the space moving magnetic field of the primary coil and also acts as a holding force in the axial direction, it is used as an axial bearing (thrust bearing). Also works.

In this embodiment, the inner rotor type in which the rotor is inside and the stator is outside is shown, but the same structure is also applicable to the outer rotor type in which the stator is inside and the rotor is outside. Can be

FIG. 3 is a sectional view of the main part of the magnetic bearing device according to the second embodiment of the present invention along the axial direction, and FIG.
It is sectional drawing along the A'plane. The present embodiment is configured like a thrust magnetic bearing, and a superconducting bulk material container 11 corresponding to a thrust disk is fixed to the rotating shaft 1. The superconducting bulk material container 11 includes the superconducting bulk material 7
Is loaded. A flat motor 12 is arranged on the stator side facing the superconducting bulk material 7. As shown in the figure, the primary coil of the motor and the superconducting bulk material fixed to the rotary shaft are aligned in the radial position R, and the coil and the superconductor are arranged so as to face each other in the axial direction. ing. The number of superconductors is matched with the number of poles of the space moving magnetic field formed by the primary coil of the motor.

That is, in this embodiment, the space moving magnetic field formed by the flat motor has four poles and rotates on the circumference of radius R. The magnetic flux of the space magnetic field formed by the primary coil of the motor penetrates the superconducting bulk material 7, and the superconducting bulk material is pinned to the space moving magnetic field. Therefore, the superconductor rotates following the rotating magnetic field generated by the primary coil, and the rotating shaft rotates. Further, by the same pinning effect, the rigidity of the magnetic bearing can be increased by generating a rotating magnetic field having a magnetic flux density higher than the pinning magnetic flux density. Although the present embodiment is configured as a thrust magnetic bearing, it has a radial holding force due to the pinning force of the superconductor, and also functions as a radial magnetic bearing.

In this embodiment, the superconductor 7 has a cylindrical shape, but it may have a prismatic shape as shown in FIG. The shape is not limited to a cylinder or a prism, but may be trapezoidal or fan-shaped.

FIG. 6 is a cross-sectional view of the main part of the magnetic bearing device according to the third embodiment of the present invention, taken along the axial direction. In this embodiment, a flat coil motor 12 is provided on the upper and lower stators so that the superconducting bulk material 7 is sandwiched between the magnetic bearing devices of the second embodiment. The superconducting bulk material 7 accommodated in the thrust disk-shaped superconducting bulk material accommodating portion 11 fixed to the rotating shaft 1 is pinned by the space moving magnetic field based on the alternating current of the primary coils 12 of the motors on the upper and lower sides. , The superconducting bulk material 7 receives a rotational driving force and a vertical supporting force from both upper and lower surfaces while being spatially held apart from each other by the gap G. When the superconductor is pinned to the magnetic flux, the same pinning force acts even if the positional relationship between the coil and the superconductor is turned upside down (phishing effect). In this embodiment, since the superconducting bulk material is supported from both the upper and lower sides by the pinning effect, the rigidity of the magnetic bearing is increased and the rotational driving force is strengthened as compared with the magnetic bearing device of the second embodiment.

FIG. 7 is an explanatory view showing a magnetic bearing device of a third embodiment of the present invention. The rotating body 2 such as an impeller is supported at both ends of its rotating shaft 1 by a first magnetic bearing device 20 and a second magnetic bearing device 21. The first magnetic bearing device 20 and the second magnetic bearing device 21 are the magnetic bearing devices shown in the first to third embodiments. In this embodiment, the magnetic bearing device 2 supporting both ends of the rotary shaft 1 is used.
0 and 21 can support the rotating shaft and can also serve as a motor for rotating the rotating shaft 1. Therefore, the motor 3 of the conventional magnetic bearing device shown in FIG. 8 is unnecessary, the length of the rotating shaft 1 can be shortened correspondingly, and the weight of the rotating body can be reduced. Therefore, it is possible to increase the natural frequency of the rotary shaft system, reduce the space, reduce the weight, and stabilize the vibration of the rotary shaft system.

[0016]

As described above, according to the present invention, the superconducting bulk material is fixed to the rotating body, and the polarity of the space moving magnetic field by the coil installed on the stator side is matched with the pinning polarity of the bulk material. With this, it is possible to configure a magnetic bearing device that doubles as a magnetic bearing and a motor. Therefore,
The length of the rotating shaft can be shortened, the natural frequency of bending of the rotating body can be increased, and the weight of the rotating body can be reduced.

[Brief description of drawings]

FIG. 1A is a sectional view of a main part taken along a radial direction of FIG. 1A of a magnetic bearing device according to a first embodiment of the present invention, and FIG. 1B is a sectional view of a main part taken along an axial direction.

2 is an explanatory view of the operation of the magnetic bearing device shown in FIG.

FIG. 3 is a cross-sectional view of a main portion of a magnetic bearing device according to a second embodiment of the present invention along the radial direction.

FIG. 4 is a cross-sectional view taken along the line AA ′ of FIG.

5 is a cross-sectional view taken along the line AA ′ of FIG.

FIG. 6 is a cross-sectional view of a main part along the axial direction of a magnetic bearing device according to a third embodiment of the present invention.

FIG. 7 is an explanatory diagram of a magnetic bearing device according to a third embodiment of the invention.

FIG. 8 is an explanatory diagram of a conventional magnetic bearing device.

[Explanation of symbols] 1 rotating shaft 7 superconductor 10 stator 11 superconductor container 20, 21 magnetic bearing device N, S pole of space moving magnetic field

Claims (5)

[Claims] 1. A magnetic bearing device for fixing a superconductor to a rotating body and supporting a rotating shaft in a non-contact manner by a pinning effect and a Meissner effect, and a stator provided with a primary coil of a rotary drive motor, And a rotating body provided with a superconductor arranged so as to face the stator through a gap, the number of the superconductor being adjusted to the number of poles of the space moving magnetic field formed by the primary coil of the motor. The magnetic bearing device is characterized in that 2. A primary coil of the motor and a superconductor of the rotating body are arranged to face each other in a radial direction,
The magnetic bearing device according to claim 1, wherein the axial positions thereof are aligned. 3. The primary coil of the motor and the superconductor of the rotating body are arranged so as to face each other in the axial direction, and their radial positions are aligned with each other. Magnetic bearing device. 4. The magnetic bearing device according to claim 1, wherein the magnetic bearing device is arranged at two or more positions in the axial direction of the rotary shaft. 5. The stator provided with the primary coil of the motor is arranged on both sides of the rotor provided with the superconductor with the rotor provided therebetween. The magnetic bearing device described.