JP3174865B2 - Superconducting bearing device and start-up method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a superconducting bearing device using a superconductor permitting magnetic flux penetration and a method of starting the same.

[0002]

2. Description of the Related Art For example, Japanese Patent Application Laid-Open No.
The thing as shown in 3-243523 is known.

[0003] This superconducting bearing uses a first-class superconductor, that is, a superconductor that completely blocks the intrusion of magnetic flux, and utilizes the complete diamagnetic phenomenon of the superconductor. In this superconducting bearing, both ends of a rotating shaft made of a superconductor are respectively inserted into recesses of a pair of supporting members made of a magnetic material having a magnetic pole, and the rotating shaft is supported in a non-contact manner in an axial direction. It is configured as follows.

In this conventional superconducting bearing, as described above, non-contact support is performed utilizing the property of complete diamagnetism, so that the direction orthogonal to the direction of repulsion becomes unstable. About the support member that supports both ends of
It is necessary to process both ends of the rotating shaft into a shape that wraps around the both ends, and it is necessary to magnetize the axially and radially opposed parts between both ends of the rotating shaft and the support member, which is cumbersome to manufacture and design. Met.

Therefore, the applicant of the present invention has proposed a superconducting bearing which can stably support rotation with a simple structure, and a permanent magnet attached to a rotating shaft and a superconductor arranged to face the permanent magnet. Wherein the permanent magnet is mounted on the rotating shaft so that the magnetic flux distribution around the rotating shaft center of the rotating shaft does not change by rotation, and the superconductor has a magnetic flux of the permanent magnet. A superconducting bearing which allows penetration and is arranged at a separated position where the magnetic flux of the permanent magnet penetrates by a predetermined amount and at a position where the distribution of the penetrating magnetic flux does not change due to the rotation of the rotating shaft has been proposed. (See Japanese Patent Application No. 2-188693). In this superconducting bearing,
The magnetic flux emitted from the permanent magnet of the rotating shaft penetrates into the inside of the superconductor and is constrained, and the permanent magnet and the superconductor are held in a state of facing each other at a predetermined distance by the action of the magnetic flux. .

[0006]

The superconducting bearing as described above can be applied to, for example, a bearing device of a high vacuum pump. In this case, before starting the operation of the superconducting bearing, the superconductor and the permanent magnet are required. Because there is no mechanism to determine the relative position of
There is a problem that the operation efficiency of the superconducting bearing is poor. Also,
During the rotation of the rotating shaft, the flux creep phenomenon, in which the weaker binding force of the magnetic flux that has entered the superconductor comes off the superconductor, etc., causes the supporting force of the rotating shaft to decrease and becomes unstable. The rotation of the rotating shaft becomes unstable.

An object of the present invention is to provide a superconducting bearing device which solves the above problems.

[0008]

SUMMARY OF THE INVENTION A superconducting bearing device according to the present invention comprises a rotating shaft disposed inside a casing so as to be capable of axial and radial movement and rotation.
The superconducting bearing is rotatably supported in a non-contact state. The superconducting bearing includes a permanent magnet attached to the rotating shaft and a superconductor attached to the casing so as to face the permanent magnet. And the permanent magnet is
The superconductor is attached to the rotating shaft so that the magnetic flux distribution around the rotating shaft center of the rotating shaft does not change due to rotation, and the superconductor allows magnetic flux to enter the permanent magnet. A superconducting bearing device which is attached to a casing so as to be located at a separated position where a magnetic flux of a magnet enters by a predetermined amount and a position where a distribution of an intruding magnetic flux does not change due to rotation of the rotating shaft, wherein the casing has
An initial positioning mechanism having upper and lower elevating members for positioning the rotary shaft with the rotary shaft sandwiched from above and below is provided.

In the method for starting a superconducting bearing device according to the present invention, a rotating shaft arranged inside a casing so as to be able to move and rotate in the axial and radial directions is rotatably supported by a superconducting bearing in a non-contact state. Wherein the superconducting bearing comprises a permanent magnet attached to the rotating shaft and a superconductor attached to the casing so as to face the permanent magnet, and the permanent magnet is The superconductor is attached to the rotating shaft so that the magnetic flux distribution around the axis of rotation of the shaft does not change due to rotation, and the superconductor allows magnetic flux to enter the permanent magnet. The superconducting bearing device mounted on the casing is located at a separated position where a predetermined amount of magnetic flux enters and at a position where the distribution of the entering magnetic flux does not change due to the rotation of the rotating shaft. The upper and lower elevating members support the rotating shaft from above and below, and the elevating member is moved up and down to position the rotating shaft, cool the superconductor, and apply the magnetic flux emitted from the permanent magnet to the superconductor. Penetrating and restraining, lowering the lower elevating member, lowering the support of the rotating shaft, lowering the upper elevating member, pushing the rotating shaft downward, applying a load to the rotating shaft, The lifting member is lifted and separated from the rotating shaft to start rotating the rotating shaft.

[0010]

According to the present invention, the permanent magnet and the superconductor are held in a state of facing each other at a predetermined distance by the restraining action of the magnetic flux of the permanent magnet that has entered the superconductor of the superconducting bearing. In this state, it is possible to rotate the rotation shaft including the permanent magnet around its axis. At this time, the magnetic flux that has entered the superconductor does not become a resistance that hinders rotation as long as the magnetic flux distribution is uniform and invariant with respect to the rotation axis. Therefore, it is possible to support the superconductor in a non-contact manner in the axial direction and the radial direction only by positioning the permanent magnet provided on the rotation shaft at a predetermined position relative to the superconductor.

According to the superconducting bearing device of the present invention, the rotation shaft can be positioned with respect to the casing by the initial positioning mechanism before the operation of the superconducting bearing is started. And the relative position of the permanent magnet of the rotating shaft can be set. Then, by moving the vertically moving member up and down with the rotating shaft interposed therebetween, the rotating shaft can be positioned at an arbitrary position. As a result, the relative position between the superconductor and the permanent magnet can be arbitrarily set, and by setting the relative position arbitrarily, efficient operation of the superconducting bearing becomes possible.

According to the starting method of the superconducting bearing device of the present invention, the rotating shaft can be positioned at an arbitrary position by sandwiching the rotating shaft between the upper and lower elevating members, thereby positioning the rotating shaft at an arbitrary position. The relative position between the body and the permanent magnet can be set arbitrarily. In addition, by cooling the superconductor, in a state where the magnetic flux generated from the permanent magnet is penetrated into the superconductor and restrained, the rotating shaft is pushed downward by the upper elevating member, and a load is applied to this. Flux creep during operation is reduced.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

The drawings schematically show the overall structure of a superconducting bearing device, which comprises a vertically arranged casing (1) and a rotatably supported non-contacting center in the casing (1). A vertical axis of rotation (2).

The casing (1) is composed of a plurality of components, and has a thick cylindrical shape having upper and lower ends opened as a whole. A high-frequency motor (3) for rotating the rotating shaft (2) at high speed is provided in the upper and lower central part of the casing (1), and a superconducting bearing for supporting the rotating shaft (2) in a non-contact state above and below it. (4) and (5) are provided.

The motor (3) comprises a stator (6) provided on a casing (1) and a rotor (7) provided on a rotating shaft (2).
It is composed of

The upper superconducting bearing (4) is constructed as follows. An annular hollow coolant case (8) is fixed in the casing (1). A through hole (9) is formed in the center of the case (8) and penetrates it vertically, and the rotating shaft (2) is passed through the hole (9) with a gap. An annular groove (10) is formed in the center of the inner peripheral wall of the hole (9) of the case (8), and the inside diameter of the bottom of this groove (10) is considerably larger than the inside diameter of the hole (9). Has become. A perforated disk-shaped permanent magnet (11) is fixed to the rotating shaft (2), and only the case (8)
With a gap. This magnet (11)
Has a magnetic pole of one magnetic pole (for example, N pole) at the upper end and a magnetic pole of the other magnetic pole (for example, S pole) at the lower end, and the magnetic flux distribution around the rotation axis of the rotation shaft (2) rotates. It is attached to the rotating shaft (2) so that it does not change due to
An annular upper superconductor (12) is fixed to the upper surface of the upper wall of the groove (9) in the case (8). Only in case (8)
An annular lower superconductor (13) is fixed to the lower surface of the lower wall of (9). These superconductors (12) (13), yttrium-based high temperature superconductor, for example, YBa ₂ Cu ₃ O _x and an internal in the normal conducting particles of the substrate (Y ₂ Ba ₁ Cu ₁₎ uniformly mix And has the property of restricting the intrusion of the magnetic flux emitted from the permanent magnet (11). The superconductors (12) and (13) are located at separated positions where the magnetic flux of the permanent magnet (11) enters by a predetermined amount, and are located at positions where the distribution of the entering magnetic flux does not change due to the rotation of the rotating shaft (2). To case
(8) Installed. At least the wall of the groove (9) of the case (8) and the inner peripheral wall corresponding to the superconductors (12) and (13) above and below it are made of a non-magnetic material.

The structure of the lower superconducting bearing (5) is the same as that of the upper superconducting bearing (4), and the same parts are denoted by the same reference numerals.

The case (8) of the upper and lower superconducting bearings (4) (5)
They are communicated by a communication pipe (14) passed through the casing (1). The upper case (8) is connected to a coolant introduction pipe (15) that extends through the casing (1) and extends to the outside, and the lower case (8) is connected to a similar coolant discharge pipe (16). I have. The coolant inlet pipe (15) of the upper case (8) is connected to the coolant outlet pipe (discharge pipe) (1) of the cooling device (18) equipped with a refrigerator or the like.
9), the lower case (8) is connected to a coolant return pipe (suction pipe) (20) of the cooling device (18). Then, the cooling device (18) supplies a coolant such as liquid nitrogen to the access pipe (19), the introduction pipe (15), the upper case (8), and the communication pipe (1).
4), circulated through the lower case (8), the discharge pipe (16) and the return pipe (20), and the superconductors (12) and (13) are cooled by the coolant filled in the case (8). . As a result, the superconductors (12) and (13) enter a superconducting state, and most of the magnetic flux generated from the permanent magnet (11) of the rotating shaft (2) is superconductor (12) (1).
Intrusion into 3) will be restrained (trap phenomenon). Here, since the superconductors (12) and (13) have normal particles uniformly mixed therein, the distribution of the magnetic flux penetrating into the superconductors (12) and (13) becomes constant. As if the permanent magnet (11) of the rotating shaft (2) penetrated the virtual pin set up on the superconductors (12) and (13), the rotating shaft was moved with respect to the superconductors (12) and (13). (2) is bound. Therefore, the rotating shaft (2)
Will be supported in the axial and radial directions in a very stable floating state.

Ring-shaped protective members (21) and (22) are fixed to the upper and lower parts of the casing (1). Correspondingly, a pair of ceramic rolling bearings are mounted on the upper and lower parts of the rotating shaft (2). Touch-down bearings (23) and (24) are provided. A shallow annular groove (2) is formed on the inner peripheral surface of the protection members (21) and (22).
5) and (26) are formed, and touch-down bearings (23) and (24) are arranged with a gap inside the grooves (25) and (26). The touch-down bearings (23) and (24) are capable of receiving a radial load and an axial load, and include, for example, a pair of angular ball bearings in a front combination or a back combination.

During operation, if the superconductors (12) and (13) of the superconducting bearings (4) and (5) become normal conductive and lose their supporting force, the upper and lower touch-down bearings (23) ) (24) is the casing
(1) comes into contact with the protection members (21) and (22), thereby
(2) is rotatably supported. For this reason, damage to the rotating shaft (2) and components around it is prevented.

The above superconducting bearing device has the following features:
Before the operation, an initial positioning device (27) is provided to set the vertical relative position of the casing (1) and the rotating shaft (2), that is, the vertical position of the superconductors (12) (13) and the permanent magnet (11). Have been.

At the lower opening end of the casing (1), there is provided a lower elevating member (28) which can be raised and lowered by known suitable means. Conical projections (2
A conical hole (30) into which the projection (29) fits is formed on the lower end surface of the rotating shaft (2) opposed to this. Further, an upper elevating member (33) similar to the above is provided at an upper opening end of the casing (1). A hole (32) is formed in the center of the upper elevating member (33) so as to penetrate it vertically, and
At the upper end of (2), a connecting member (31) protruding upward through the hole (32) is provided. The lower end of the hole (32) is formed with a tapered portion (32a) whose lower side is widened. Connecting member (31)
A lower portion of the connecting member (3a) is formed at the lower portion of the connecting member (31a), the lower portion of which is widened corresponding to the tapering portion (32a) of the hole (32).
The straight portion having a smaller outer diameter above the tapered portion (31a) of 1) is passed through a gap between the straight portion having a smaller inner diameter above the tapered portion (32a) of the hole (32). .

In operation, the lower lifting member (28) is lowered to the lower operating position, and the upper lifting member (33) is raised to the upper operating position, and as described above, the superconducting bearing (4) ( The rotating shaft (2) is supported by 5) so that the lower lifting member
The protrusion (29) of (28) moves away from the wall of the conical hole (30) of the rotating shaft (2), and the tapered portion (31a) of the rotating shaft (2) is tapered (32a) of the upper lifting member (33). Away from Also, usually
The rotating shaft (2) rotates while being supported substantially at the center of the casing (1), and the permanent magnet (11) is supported substantially at the vertical center of the case (8) in the case (8).

At the time of the stop, the supply of the coolant from the cooling device (18) is usually stopped. Therefore, the superconductor (12) (1
3) is in the normal conduction state and has lost its bearing capacity. Therefore, the rotating shaft (2) is stopped while being supported by the casing (1) via the touchdown bearings (23) and (24).

Such a stopped bearing device is started, for example, as follows.

First, the upper lifting member (33) is lowered from the operating position to an appropriate position, and the lower lifting member (28) is raised from the operating position to an appropriate position. When the lower elevating member (28) rises, first, the protrusion (29) of the elevating member (28) comes into close contact with the conical hole (30) of the rotating shaft (2), and the rotating shaft (2) is lifted upward. Then, the tapered portion (31a) of the rotating shaft (2) comes into close contact with the tapered portion (32a) of the upper lifting member (33), and the rotating shaft (2) and the lower lifting member (28) stop. As a result, the rotating shaft (2) is supported in a state sandwiched between the upper and lower elevating members (33) and (28), and the conical protrusion (29) of the lower elevating member (28) is conical with the rotating shaft (2). Hole (30)
And the tapered portion (31a) of the rotating shaft (2) comes into close contact with the tapered portion (32a) of the upper lifting member (33).
The rotating shaft (2) is positioned at the center of the casing (1).
Then, with the rotating shaft (2) supported in this manner, the upper and lower elevating members (33) and (28) are moved up and down synchronously to position the rotating shaft (2) at an arbitrary position. Normally, the permanent magnet (11) approaches the upper wall of the groove (9) of the case (8), and the distance from this wall to the upper surface of the permanent magnet (11) is higher than the lower wall of the groove (9). It should be smaller than the distance to the lower surface of the permanent magnet (11). When the rotating shaft (2) is positioned in this way, the coolant is circulated through the superconducting bearings (4) and (5) by the cooling device (18) to cool the superconductors (12) and (13). . Superconductor
(12) When the (13) is cooled and enters the superconducting state, the supporting force is generated as described above. First, the lower elevating member (28) is lowered to the operating position, and the supporting by this is eliminated. When the supporting force of the lower elevating member (28) is lost, the rotating shaft (2) slightly descends by its own weight and stops at a position that balances the magnetic repulsive force and pinning force of the superconducting bearings (4) (5). I do. Normally, the rotary shaft (2) stops at a position where the permanent magnet (11) is located substantially in the vertical center of the case (8). Next, lower the upper elevating member (33) and push the rotating shaft (2) slightly downward,
After applying a load, the upper lifting member (33) is raised to the operating position and separated from the rotating shaft (2). As a result, the rotating shaft (2) slightly rises and returns to almost its original position, and is supported in a non-contact state as described above. To start.

The rotating shaft (2) before rotation, which is supported by the superconducting bearings (4) and (5) in a non-contact state as described above, is moved upward and downward.
By applying a load by pushing downward in (33), flux creep during rotation can be reduced, and as a result, the rotating shaft (2) can be rotated stably.

The configuration of the superconducting bearings (4) and (5) is not limited to that of the above embodiment, but can be changed as appropriate. In the superconducting bearing, a cylindrical permanent magnet is attached to the outer circumference of the rotating shaft,
One type has magnetism of one magnetic pole at one end and magnetism of the other magnetic pole at the other end, and there is also a type in which a cylindrical, partially cylindrical or plate-like superconductor is arranged around this permanent magnet. However, the present invention is also applicable to a superconducting bearing device using such a superconducting bearing.

[0030]

According to the superconducting bearing device of the present invention, as described above, the rotating shaft can be stably supported by the superconducting bearing having a simple structure, and the rotating shaft can be fixed to the casing before operation. The rotating shaft can be positioned at any position, and the relative position between the casing and the rotating shaft can be set arbitrarily.
Therefore, efficient driving can be performed.

According to the method of starting a superconducting bearing device of the present invention, the relative position between the casing and the rotating shaft is set arbitrarily by positioning the rotating shaft at an arbitrary position with respect to the casing, thereby improving the efficiency. Driving can be performed, and flex creep during rotation can be reduced, and the rotating shaft can be rotated stably.

[Brief description of the drawings]

FIG. 1 is a schematic vertical sectional view of a superconducting bearing device showing an embodiment of the present invention.

[Explanation of symbols]

 (1) Casing (2) Rotary shaft (4) (5) Superconducting bearing (11) Permanent magnet (12) (13) Superconductor (27) Initial positioning device. (28) Lower lifting member (33) Upper lifting member

Claims (2)

(57) [Claims] A rotating shaft disposed inside a casing so as to be able to move and rotate in an axial direction and a radial direction is rotatably supported in a non-contact state by a superconducting bearing. A bearing is composed of a permanent magnet attached to the rotating shaft and a superconductor attached to the casing so as to face the permanent magnet, and the permanent magnet is provided with a magnetic flux distribution around a rotating axis of the rotating shaft. Are attached to the rotating shaft so as not to be changed by rotation, and the superconductor allows the magnetic flux of the permanent magnet to enter, and is a separated position where the magnetic flux of the permanent magnet enters by a predetermined amount. And a superconducting bearing device mounted on a casing such that the distribution of the invading magnetic flux does not change due to rotation of the rotating shaft. A superconducting bearing device, comprising: an initial positioning mechanism provided with upper and lower elevating members for positioning by sandwiching between them. 2. A rotating shaft arranged inside the casing so as to be capable of axial and radial movement and rotation, is rotatably supported in a non-contact state by a superconducting bearing. A bearing is composed of a permanent magnet attached to the rotating shaft and a superconductor attached to the casing so as to face the permanent magnet, and the permanent magnet is provided with a magnetic flux distribution around a rotating axis of the rotating shaft. Are attached to the rotating shaft so as not to be changed by rotation, and the superconductor allows the magnetic flux of the permanent magnet to enter, and is a separated position where the magnetic flux of the permanent magnet enters by a predetermined amount. And a superconducting bearing device attached to the casing such that the distribution of the invading magnetic flux does not change due to the rotation of the rotating shaft. Supporting from below, the rotating shaft is positioned by raising and lowering the elevating member, cooling the superconductor, allowing the magnetic flux emitted from the permanent magnet to enter the superconductor and restraining it, and the lower elevating member To remove the support of the rotating shaft, lower the upper elevating member, and push down the rotating shaft to apply a load to the rotating shaft, raise the upper elevating member, and separate from the rotating shaft. And starting the rotation of the rotating shaft.