JP2000136825A - Starting method for superconducting bearing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a starting method for a superconducting bearing device which can lengthen a time capable of supporting a rotor continuously by a superconducting bearing. SOLUTION: A rotor 1 is contactlessly supported to a prescribed position in a radial direction by control type radial magnetic bearings 3, 4, also in a condition that the rotor 1 is contactlessly supported to a prescribed position in an axial direction by generating upward direction supporting force in a control type axial magnetic bearing 8, after a superconductor 22 of a superconducting bearing 2 placed in a superconducting condition is made to rise up to a position generating downward directional supporting force in the axial magnetic bearing 8 by generating upward directional supporting force larger than weight of the rotor 1 in the superconducting bearing 2, the superconductor 22 is lowered down to a position zeroing the supporting force by the axial magnetic bearing 8, and it is placed in an inoperative condition.

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 applied to, for example, a fluid machine or a machine tool requiring high-speed rotation, or a power storage device for converting surplus power into kinetic energy of a flywheel and storing it. About how to start.

[0002]

2. Description of the Related Art As a superconducting bearing device capable of stably supporting rotation with a simple structure, the present applicant has disclosed a permanent magnet attached to a rotating body and a second type superconducting member arranged to face the permanent magnet. The permanent magnet is attached to the rotating body so that the magnetic flux distribution around the rotation axis of the rotating body does not change due to rotation, and the superconductor allows the permanent magnet to enter the magnetic flux. (Refer to Japanese Patent Application Laid-Open No. 4-78316) which is disposed at a separated position where a predetermined amount of magnetic flux enters and where the distribution of the entering magnetic flux does not change due to rotation of the rotating body.

Before starting the operation of the superconducting bearing device, there is no mechanism for determining the relative position between the superconductor and the permanent magnet. There was a problem that the operating efficiency of the bearing device was poor.

Accordingly, the present applicant further proposes a rotating body vertically arranged in a fixed portion, a superconducting bearing for supporting the rotating body at least in the axial direction and floating in a non-contact manner, and a radial displacement of the rotating body. A radial displacement sensor for detecting, a control-type radial magnetic bearing for non-contactly supporting the rotating body at a predetermined position in the radial direction, an axial displacement sensor for detecting an axial displacement of the rotating body, and the rotating body as necessary. Axial magnetic bearing, which controls the radial magnetic bearing, the axial magnetic bearing and the superconducting bearing based on the output signals of the radial displacement sensor and the axial displacement sensor, and a rotating body that supports the rotor in a non-contact manner at a predetermined position in the axial direction. It is equipped with a rotating electric motor, and the superconducting bearing has a permanent magnet Fine proposed permanent magnets below the superconducting magnetic bearing device having the second type superconductor which is provided vertically movably on the fixed portion side (see Japanese Patent Laid-Open No. 10-231840).

In this superconducting bearing device, after the rotating body is positioned at a desired operating position by a radial magnetic bearing and an axial magnetic bearing as described below, it is non-contactly supported at this operating position by a radial magnetic bearing and a superconducting magnetic bearing. , The operation can be started, so that efficient operation can be performed.

First, in a state where the electric motor is stopped, the rotating body is moved in the radial direction (horizontal direction) by a radial magnetic bearing.
In a non-contact manner, and in a non-contact manner in an axial direction (vertical direction) by an axial magnetic bearing, and levitated to a predetermined operation position (stable rotation position) with respect to a fixed portion. Axial magnetic bearings usually include a pair of upper and lower electromagnets that attract and hold the flange of the rotating body from both sides in the axial direction. Each electromagnet receives an exciting current for attracting the flange from the control device. Supplied.

When the rotating body is levitated to the operating position as described above, the weight of the rotating body is supported only by the axial magnetic bearing, so that the upward attractive force of the upper electromagnet is reduced by the downward electromagnet. It is larger by the weight of the rotating body than the attraction force, and generates an upward supporting force as the axial magnetic bearing as a whole. Also, at this time, the superconductor on the fixed portion side of the superconducting bearing is kept in a normal conducting state at room temperature,
The superconductor is lowered to a position sufficiently distant from the permanent magnet on the rotating body side of the superconducting bearing (a position hardly affected by the magnetic flux of the permanent magnet). Then, at this position, the superconductor is cooled to a predetermined temperature and maintained in the superconducting state in which the second type superconducting state appears.

Next, the superconductor is raised to a position where the superconductor is opposed to the permanent magnet with a predetermined gap in a state where the rotating body is held at the operating position by the axial magnetic bearing and the radial magnetic bearing. Then, a part of the magnetic flux emitted from the permanent magnet partially enters the superconductor, and the entered magnetic flux is pinned to a pinning point inside the superconductor.

Next, the superconductor is further raised. When the rotating body is held in the operating position by the axial magnetic bearing and the superconductor of the activated superconducting bearing is raised, the upward supporting force of the superconducting bearing gradually increases, and the axial magnetic bearing The upward support force gradually decreases. That is, the upward attractive force of the upper electromagnet of the axial magnetic bearing gradually decreases, and accordingly, the downward attractive force of the lower electromagnet gradually increases, and the upward supporting force of the entire axial magnetic bearing gradually increases. Become smaller. Then, the upward attractive force of the upper electromagnet of the axial magnetic bearing and the downward attractive force of the lower electromagnet became equal to each other, and the upward support force of the entire axial magnetic bearing, that is, the axial support force became zero. At this point, the superconductor is stopped. Then, the supply of the exciting current to the electromagnet of the axial magnetic bearing is stopped, and this is brought into a non-operating state.

Thus, the weight of the rotating body is supported only by the superconducting bearing, and the rotating body is non-contactly supported at the operating position by the superconducting bearing and the radial magnetic bearing. When the rotating body is thus supported by the superconducting bearing and the radial magnetic bearing, the electric motor is driven. As a result, the superconducting bearing device starts operating, and the rotating body is rotated while being held at the operating position by the superconducting bearing and the radial magnetic bearing.

In the above-described superconducting bearing device in which a vertical rotating body is supported by a superconducting bearing in an axial direction and floats in a non-contact manner, the rotating body is supported and rotated by a radial magnetic bearing and a superconducting bearing. During operation, the magnetic levitation force of the superconducting bearing decreases due to magnetic flux creep of the superconducting bearing with the passage of time, and the position of the rotating body gradually lowers, and eventually the touchdown occurs. When the touchdown occurs in this manner, it is necessary to stop the rotating body, perform the initial positioning of the rotating body as described above, and restart the operation, and the operation for restarting the operation is very troublesome. . Moreover, if the touchdown is performed many times, the touchdown bearing is damaged.

In order to solve such a problem, in the above-described superconducting device, the control device operates as follows in a state where the rotating body is rotating in a state where the rotating body is supported in a non-contact manner by the radial magnetic bearing and the superconducting bearing. The rotating body is supported in the operating position by controlling the vertical position of the superconductor based on the output of the displacement sensor, and when the control of the position of the rotating body by controlling the position of the superconductor reaches the limit, axial magnetic The bearing is operated to support the rotating body at the operating position.

That is, during operation, the control device axially reduces the displacement of the rotating body when the magnetic levitation force of the superconducting bearing decreases due to magnetic flux creep over time and the position of the rotating body gradually decreases from the operating position. The displacement is detected by the displacement sensor, the superconductor is raised by that amount, and feedback control is performed so that the rotating body is maintained at the operating position. This control is performed until the superconductor reaches a predetermined ascending limit position, and thereafter,
The control of the position of the superconductor is not performed until the rotating body has lowered to the predetermined lower limit position. Then, when the rotating body falls below the lower limit position, the axial magnetic bearing is operated, and the rotating body is again held at the operating position by the axial magnetic bearing. At this time, the rotating body continues to rotate.

The lower limit position is set above the position where the rotating body touches down. Therefore, before the rotating body touches down, the rotating body is rotated and operated by the axial magnetic bearing. Position can be supported. Then, in a state where the rotating body is held and rotated by the axial magnetic bearing and the radial magnetic bearing, the superconductor is lowered, and the complete second-class superconducting state is obtained again. The superconductor is raised, the weight of the rotating body is supported only by the superconducting bearing, and the axial magnetic bearing is deactivated. As a result, the operation of the superconducting bearing device is restarted, and the rotating body is again supported at the operating position by the superconducting bearing and the radial magnetic bearing, and continues to rotate.

As described above, even if the magnetic levitation force of the superconducting bearing is lowered and the position of the rotating body is lowered, before the rotating body is touched down, the rotating body is rotated using the axial magnetic bearing. Operation can be resumed. Therefore, it is possible to operate continuously for a long time without touching down the rotating body.

However, even in this case, at the initial stage after the start of operation, magnetic flux creep of the superconducting bearing occurs,
In order to support the rotating body that is going to descend in the driving position,
The superconductor soars. For this reason, the gap between the permanent magnet of the superconducting bearing and the superconductor is sharply reduced, and the time required for the superconductor to reach the rising limit position is shortened. Therefore, the time during which the rotating body can be continuously supported by the superconducting bearing is reduced.

In the superconducting bearing constituting the superconducting bearing device, besides the permanent magnet and the superconductor facing in the axial direction as described above, there are also those in which they face in the radial direction. There is the same problem as above.

[0018]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to provide a method of starting a superconducting bearing device capable of extending the time during which a rotating body can be continuously supported by a superconducting bearing. It is in.

[0019]

According to the present invention, there is provided a method for starting a superconducting bearing device, comprising: a rotating member disposed vertically in a fixed portion; and a non-contact member which supports the rotating member at least in an axial direction. A superconducting bearing to levitate, a control-type radial magnetic bearing that supports the rotating body in a non-contact manner in the radial direction, a control-type axial magnetic bearing that supports the rotating body in a non-contact manner in the axial direction as needed, and rotationally drives the rotating body. A superconducting bearing, wherein the superconducting bearing comprises a permanent magnet attached to the rotating body, and a superconductor provided on the fixed portion so as to be movable up and down and facing the permanent magnet. A starting method, wherein the radial magnetic bearing supports the rotating body at a predetermined position in a radial direction in a non-contact manner, and In a state where the rotating body is supported in a non-contact manner at a predetermined position in the axial direction by generating an upward supporting force on the magnetic bearing, the superconductor in the superconducting state is upwardly directed to the superconducting bearing by an amount larger than the weight of the rotating body. After the supporting force of the axial magnetic bearing is raised to a position where a downward supporting force is generated in the axial magnetic bearing, the axial magnetic bearing is lowered to a position where the supporting force of the axial magnetic bearing is reduced to zero, and the axial magnetic bearing is not operated. It is characterized by the following.

The permanent magnet and the superconductor of the superconducting bearing may be vertically opposed or horizontally opposed.

For example, the superconductor is a second-class superconductor having a property that a second-class superconducting state appears by cooling, and in the second-class superconducting state, a magnetic flux that penetrates is restricted and pinned, The superconducting bearing supports the rotating body in a non-contact manner in an axial direction and a radial direction by a pinning force of the superconductor. In this case, the permanent magnet of the superconducting bearing is attached to the rotating body so that the magnetic flux distribution around the rotation axis of the rotating body does not change due to rotation, and the second-type superconductor penetrates by a predetermined amount of the magnetic flux of the permanent magnet. It is located at a separated position and at a position where the distribution of the invading magnetic flux does not change due to the rotation of the rotating body.

According to the method of the present invention, the rotating body is supported by the radial magnetic bearing in a non-contact manner at a predetermined position in the radial direction, and the axial magnetic bearing generates an upward supporting force, thereby rotating the rotating body in the predetermined axial direction. With the non-contact support at the position, the superconductor in the superconducting state was raised to a position where the superconducting bearing generates an upward supporting force larger than the weight of the rotating body and the axial magnetic bearing generates a downward supporting force. Then, by lowering the supporting force of the axial magnetic bearing to a position where it becomes zero, a preload is applied to the superconducting bearing, and magnetic flux creep generated in the superconducting bearing at the beginning of operation is generated in advance, and operation is started. Of the rotating body due to magnetic flux creep and the resulting superconductor sudden rise during the initial stage Therefore, the time required for the superconductor to reach the ascending limit position becomes longer, and the time during which the superconductor bearing can continuously support the rotating body becomes longer.

[0023]

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

FIGS. 1 and 2 show a first embodiment in which the present invention is applied to a power storage device.

FIG. 1 schematically shows an example of the overall configuration of a superconducting bearing device of a power storage device, and FIG. 2 shows an example of the electrical configuration thereof.

The superconducting bearing device is a vertical shaft-shaped rotating body.
(1), superconducting bearing (2), two sets of upper and lower radial displacement detection units (3) (4), two sets of upper and lower control radial magnetic bearings (5)
(6), an axial displacement sensor (7), a control type axial magnetic bearing (8), and a built-in motor (9) .These components constitute the fixed part (A), the upper housing (10), the intermediate housing ( 11) and located inside the lower housing (12). The upper housing (10) has a stepped vertical cylindrical shape that is relatively short in the vertical direction and has a large diameter in about half of the lower side. The intermediate housing (11) has a diameter substantially the same as the small diameter portion on the upper side of the upper housing (10), and has a vertically long vertical cylindrical shape. The lower housing (12) has substantially the same diameter as the large-diameter portion on the lower side of the upper housing (10), and has a vertically short vertical cylindrical shape. The three housings (10), (11) and (12) are formed integrally and concentrically by connecting a plurality of parts.

In the following description, the axis in the axial direction (vertical axis) is defined as the Z axis, and one radial axis (horizontal axis) orthogonal to the Z axis is defined as the X axis, and the radial axis orthogonal to the Z axis and the X axis. The axis of the direction (horizontal axis) is the Y axis.

The rotating body (1) is arranged concentrically at the center in the housing (10) (11) (12). An upper flywheel (13) located in the large-diameter portion below the upper housing (10) is fixed to the upper part of the rotating body (1), and a lower part of the lower housing (12) is fixed to the lower part of the rotating body (1). The lower flywheel (14) located at the upper part is fixed. These flywheels (13) and (14) are for storing surplus electric power as kinetic energy.

The superconducting bearing (2) is for supporting the rotating body (1) in the axial direction and the radial direction for non-contact floating, and is fixed concentrically to the lower end of the rotating body (1). An annular permanent magnet portion (15) and an annular superconductor portion (16) provided on the fixed portion (A) side to face the permanent magnet portion (15) in the axial direction.

The permanent magnet section (15) includes a support disk (17) as a support member fixed concentrically at the lower end of the rotating body (1), and is provided on the outer periphery of the disk (17). , Multiple annular permanent magnets
(18) is fixed via an annular ferromagnetic body (19). For example, each permanent magnet (18) has magnetic poles at both ends in the radial direction, and the permanent magnets (18) are arranged so that the magnetic poles on the radially opposite side of the permanent magnets (18) have the same polarity. Further, the permanent magnet (18) is arranged in the radial direction so as to be concentric with the rotating body (1), and the permanent magnet (18) around the rotation axis of the rotating body (1).
Are not changed by the rotation of the rotating body (1).

Although not shown in detail, a vertical shaft elevating member (20) concentric with the rotating body (1) is provided at an appropriate position below the fixed portion (A). The upper part of the elevating member (20) penetrates through the bottom wall of the lower housing (12) and enters the inside thereof, and a superconductor portion (16) is fixed to the upper end thereof, so that the elevating member (20) can be moved up and down. At the same time, the superconductor section (16) also moves up and down.

The superconductor section (16) has an annular cooling tank (cryostat) (21) fixed to the upper end of the elevating member (20) so as to be concentric with the rotating body (1). Tank (2
1) is a vertical, short and flat double cylindrical shape, the upper end surface of which is opposed to the lower end surface of the permanent magnet (18) of the permanent magnet portion (15). The portion of the upper end wall of the tank (21) facing the permanent magnet (18) has a reduced thickness, and a vertical flat annular second type superconductor (22) is provided in the tank (21) inside this portion.
Has been fixed. The superconductor (22) is arranged concentrically with the rotating body (1), and faces the permanent magnet (18) in the axial direction with a thin upper end wall of the tank (21) and a gap.

The superconductor (22) is made of, for example, an yttrium-based superconductor such as YBa ₂ Cu ₃ O _{7-x in} which normal conducting particles (Y ₂ BaCu) are uniformly mixed in a bulk. In an environment where two kinds of superconducting states appear, it has a property of restricting and pinning the magnetic flux emitted from the permanent magnet (18). And the superconductor
(22) is a lifting member by being arranged as described above.
With (20) raised to the predetermined position, the permanent magnet (1
8) at a separated position where a predetermined amount of magnetic flux enters and a rotating body
It is located at a position where the distribution of the intruding magnetic flux does not change due to the rotation of (1).

The tank (21) is connected to a suitable cooling device (not shown) through a cooling fluid supply pipe (23) and a discharge pipe (24). A cooling fluid consisting of nitrogen is circulated and
The superconductor (22) is cooled by the cooling fluid filled in 1).

The lifting member (20) is raised and lowered by a suitable lifting device (29). A load cell (30) for measuring a vertically downward load acting on the elevating member (20), that is, the superconductor (22) is provided at an intermediate portion of the elevating member (20) located below the lower housing (12). Have been. Although not shown, the rotating body (1)
In order to prevent contact between the permanent magnet part (15) and the superconductor part (16) when descending to the descending limit position described later, it is necessary that the elevating member (20) rises from a predetermined ascending limit position. Suitable stoppers are provided to prevent this.

The radial magnetic bearings (5) and (6) support the rotating body (1) in a non-contact manner, and have two rotating bodies (1) orthogonal to each other.
For controlling the positions in two radial directions (X-axis and Y-axis directions).
It is provided in the place. Each radial magnetic bearing (5) (6)
A pair of X-axis electromagnets (5x) fixed in the housing (11) so as to sandwich the rotating body (1) from both sides in the X-axis direction and sucking the rotating body (1) to both sides in the X-axis direction. (6x) and the housing (11) so as to sandwich the rotating body (1) from both sides in the Y-axis direction.
And a pair of Y-axis direction electromagnets (5y) and (6y) that are fixed inside and attract the rotating body (1) to both sides in the Y-axis direction. In the case of this embodiment, the electromagnets (5x) (5) of the radial magnetic bearings (5) and (6)
y) (6x) (6y) are all the same.

The radial displacement detecting units (3) and (4) constitute radial displacement detecting means for detecting radial displacement of the rotating body (1). The upper detection unit (3) is located near the upper radial magnetic bearing (5).
(4) are provided near the lower radial magnetic bearing (6), respectively. Each of the detection units (3) and (4) is fixed in the housing (11) so as to sandwich the rotating body (1) from both sides in the X-axis direction, and detects displacement of the rotating body (1) in the X-axis direction. The pair of X-axis direction displacement sensors (3x) and (4x) and the rotating body (1) are fixed in the housing (11) so as to sandwich the rotating body (1) from both sides in the Y-axis direction.
It comprises a pair of Y-axis direction displacement sensors (3y) and (4y) for detecting the displacement in the Y-axis direction of (1).

The axial magnetic bearing (8) controls the position of the rotating body (1) in the axial direction (Z-axis direction),
This is for positioning (1) at a predetermined position in the axial direction, and is provided in the small diameter portion on the upper side of the upper housing (10). A horizontal outward flange (25) is fixed near the upper end of the rotating body (1). Axial magnetic bearing
(8) is fixed inside the housing (10) so as to sandwich the portion near the outer periphery of the flange (25) from both sides in the Z-axis direction,
A pair of upper and lower Z-axis electromagnets (8a) and (8b) for attracting (1) to both sides in the Z-axis direction are provided. In the case of this embodiment, the same electromagnets (8a) and (8b) of the axial magnetic bearing (8) are used.

The axial displacement sensor (7) constitutes axial displacement detecting means for detecting the axial displacement of the rotating body (1), and is provided at an appropriate position of the fixed portion (A), for example, the upper housing (10). Is provided in the upper end portion of the.

Each electromagnet (5x) (5y) of each magnetic bearing (5) (6) (8)
(6x) (6y) (8a) (8b) is connected to the control device (26), and from this control device (26) to each electromagnet (5x) (5y) (6x) (6y) (8a) (8b) An exciting current is supplied. The exciting current is a combination of a constant steady current and a control current that changes depending on the displacement of the rotating body (1). Normally, the steady-state current values of all the electromagnets (5x) (5y) (6x) (6y) of the radial magnetic bearings (5) and (6) are equal to each other. In addition, each corresponding one of the radial magnetic bearings (5) and (6)
Regarding the pair of electromagnets (5x), (5y), (6x), and (6y), the absolute values of the control currents are equal to each other, and the signs are opposite to each other. For the pair of upper and lower electromagnets (8a) and (8b) of the axial magnetic bearing (8), the values of the steady currents are equal to each other, the absolute values of the control currents are equal to each other, and the signs are opposite to each other. Then, the control device (26) controls the magnitude of the control current of each electromagnet (8a) (8b) of the axial magnetic bearing (8) based on the output signal of the axial displacement sensor (7), so that the rotating body ( The axial position of (1) is controlled, and the radial displacement sensor (3
x) (3y) (4x) (4y) based on the output signal
By controlling the magnitude of the control current of each of the electromagnets (5x), (5y), (6x), and (6y) in (5) and (6), the position of the rotating body (1) in the radial direction is controlled.

The load cell (30) of the lifting member (20) is connected to the control device (26). Lifting device (29) for lifting member (20)
Is also connected to the control device (26), whereby the vertical position of the elevating member (20), that is, the superconductor (22) is controlled.

The electric motor (9) is for rotating the rotating body (1) at a high speed, and includes upper and lower radial magnetic bearings (5) and (6).
Is provided in the intermediate housing (11). The electric motor (9) includes a rotor (9a) provided on an outer peripheral portion of the rotating body (1).
And a stator (9b) fixed in the housing (11) and arranged around the rotor (9a).

When the support by the superconducting bearing (2) and the magnetic bearings (5), (6) and (8) is lost near the upper end and the lower end in the intermediate housing (11), the rotating body (1) is touched down. Bearings for mechanical and mechanical support (27, 28)
Is provided.

When the above-mentioned power storage device is stopped, the electric motor (9), the superconducting bearing (2) and the magnetic bearing (5) (6)
(8) is in a non-operating state, the rotating body (1) stops rotating, and is supported by the touch-down bearings (27) and (28). Also,
The superconductor (22) on the fixed part (A) side of the superconducting bearing (2) is far enough away from the permanent magnet (18) on the rotating body (1) side under normal temperature at normal temperature to be affected by the magnetic flux. To the lower end position where it is hardly affected.

Then, from such a state, for example,
The operation is started as follows.

First, the magnetic bearings (5), (6) and (8) are activated, and the rotating body (1) in the stopped state is moved to the radial magnetic bearings (5) and (6).
, And is supported in a non-contact manner in an axial direction by an axial magnetic bearing (8), and floats to a predetermined operation position (stable rotation position) with respect to the fixed portion (A). In the case of this embodiment, when levitating to the operating position, the rotating body (1) is located at the center of the housing (10) (11) (12), and the electromagnets (8) above and below the axial magnetic bearing (8).
a) The axial gap between the (8b) and the flange (25) of the rotating body (1) is equal to each other, and the radial magnetic bearing
(5) For the pair of electromagnets (5x), (5y), (6x), and (6y) of (6), the sizes of the radial gaps with the rotating body (1) are equal to each other. At this time, since the superconducting bearing (2) is still in a non-operating state, the weight of the rotating body (1) is supported only by the axial magnetic bearing (8), and therefore, the upward attractive force by the upper electromagnet (8a). Is larger by the weight of the rotating body (1) than the downward attractive force of the lower electromagnet (8b), and the axial magnetic bearing (8) generates an upward supporting force as a whole. That is, the control current of the upper electromagnet (8a) is a positive value, the value of the lower electromagnet (8b) is a negative value, and the value of the exciting current of the upper electromagnet (8a) is the value of the exciting current of the lower electromagnet (8b). In comparison with, the bearing capacity is increased by the upward supporting force of the entire axial magnetic bearing (8) (the weight of the rotating body (1)).

When the rotating body (1) is held in the operating position by the magnetic bearings (5), (6) and (8), a cooling fluid is supplied to the cooling tank (21) and the superconductor (22) is moved to the above-mentioned position. In step (2), the superconducting state is maintained by cooling to a predetermined temperature.

Next, the rotating body (1) is rotated by the magnetic bearings (5), (6) and (8).
With the superconductor (22) in a permanent magnet position.
It is raised to a position opposite to (18) with a predetermined gap. Then, a part of the magnetic flux emitted from the permanent magnet (18) partially intrudes into the superconductor (22), and the invading magnetic flux is pinned to a pinning point inside the superconductor (22).

Next, the superconductor (22) is further raised. With the rotating body (1) held in the operating position by the axial magnetic bearing (8), when the superconductor (22) of the activated superconducting bearing (2) is raised, the superconducting bearing (2) The supporting force gradually increases, and the upward supporting force of the axial magnetic bearing (8) gradually decreases accordingly. That is, the upper electromagnet (8
The upward attraction force due to a) gradually decreases, and accordingly, the downward attraction force due to the lower electromagnet (8b) gradually increases, and the upward supporting force of the entire axial magnetic bearing (8) gradually decreases. . Eventually, the upward attractive force of the upper electromagnet (8a) of the axial magnetic bearing (8) and the downward attractive force of the lower electromagnet (8b) become equal to each other, and the upward support force of the entire axial magnetic bearing (8). That is, the supporting force in the axial direction becomes zero. At this time, the weight of the rotating body (1) is supported by the superconducting bearing (2), and the upward supporting force of the superconducting bearing (2) is equal to the weight of the rotating body (1). The upward bearing force of the superconducting bearing (2) is superconductor
Equal to the downward load acting on (22), which is measured by the load cell (30).

As described above, even after the axial bearing force of the entire axial magnetic bearing (8) becomes zero, the superconductor (22) is further raised. Then, the upward supporting force of the superconducting bearing (2) gradually increases from the weight of the rotating body (1), and a downward supporting force equal to the increase is generated in the axial magnetic bearing (8). Then, the superconductor (22) is stopped when the upward supporting force of the superconducting bearing (2) or the increase thereof reaches a preset value.

Thereafter, the superconductor (22) is lowered, and when the supporting force of the axial magnetic bearing (8) becomes zero again, the superconductor (22) is stopped. And axial magnetic bearing
The supply of the exciting current to the electromagnets (8a) and (8b) in (8) is stopped, and the electromagnets are deactivated. Thereby, the rotating body (1)
Is supported only by the superconducting bearing (2), and the rotating body (1) is again supported in a non-contact manner at the operating position by the superconducting bearing (2) and the radial magnetic bearings (5), (6).

In the case of the above device, an axial magnetic bearing
Use the same upper and lower electromagnets (8a) and (8b) for (8), and also use the upper and lower electromagnets (8a) with the rotating body (1) in the operating position.
Since the size of the gap between (8b) and the flange (25) of the rotating body (1) is equal to each other, for the upper and lower electromagnets (8a) (8b),
The relationship between the value of the exciting current and the attractive force becomes the same. Therefore, by detecting that the exciting currents of the upper and lower electromagnets (8a) and (8b) are equal, it is possible to know that the attraction force of the upper and lower electromagnets (8a) and (8b) is equal.

Depending on the superconducting bearing device, the upper and lower electromagnets of the axial magnetic bearing may have different specifications, or the gap between the rotating body in the operating position and the upper and lower electromagnets may not be equal. . However, even in such a case, since the operating position is constant, the relationship between the value of the exciting current and the value of the attractive force is constant and can be known in advance for each electromagnet. Therefore, if the relationship between the values of the excitation currents of the upper and lower electromagnets when the attraction force of the upper and lower electromagnets is equal is checked in advance, it can be detected that the values of the excitation currents of the upper and lower electromagnets satisfy the above relationship. Thereby, it can be known that the attraction force of the upper and lower electromagnets has become equal.

If the rotating body (1) is supported by the superconducting bearing (2) and the radial magnetic bearings (5) and (6) as described above, the motor
Drive (9). As a result, the superconducting bearing device starts operating, and the rotating body (1) is rotated while being held in the operating position by the superconducting bearing (2) and the radial magnetic bearings (5, 6). At this time, the magnetic flux that has entered the superconductor (22) does not ideally become a resistance that hinders rotation as long as the magnetic flux distribution is uniform and invariant with respect to the rotation axis of the rotating body (1).

In the case of the above device, the rotating body (1) is slightly supported in the radial direction by the superconducting bearing (2) using the second type superconductor (22). (6) The supporting force by (6) can be small, and the radial magnetic bearings (5) and (6) can be downsized.

At the start of the operation, the rotating body (1) is held in the operating position by the axial magnetic bearing (8) and the radial magnetic bearings (5) and (6) from the beginning, and is returned to the operating position by the superconducting bearing (2). Since it is held, there is no need to temporarily lift the rotating body above the operating position. Therefore, the length of the rotating body (1) can be shortened accordingly.

During the operation of the above apparatus, the magnetic levitation force of the superconducting bearing (2) decreases due to magnetic flux creep over time, and the position of the rotating body (1) gradually lowers from the operation position. 26) detects the amount of displacement of the rotating body (1) with the axial displacement sensor (7), raises the superconductor (22) by that amount, and performs feedback control to keep the rotating body (1) in the operating position. .

For example, when the rotating body (1) is lowered from the operating position by a predetermined amount (for example, 0.1 mm), the lifting / lowering device (29) raises the lifting member (20) until the rotating body (1) returns to the operating position. . This control is repeated until the lifting member (20) is stopped at the lifting limit position by the stopper.

Even after the elevating member (30) has stopped at the ascending limit position, the rotating body (1) descends. However, when the rotating member (1) descends from the operating position by a predetermined amount (for example, 0.8 mm) and falls below the predetermined descending limit position. At that time, the axial magnetic bearing (8) is operated, and the rotating body (1) is again held in the operating position by the axial magnetic bearing (8). At this time, the rotating body (1) keeps rotating. The lower limit position is set above the position where the rotating body (1) touches down on the touch-down bearings (27) and (28), and therefore, before the rotating body (1) touches down, The rotating body (1) can be supported at the operating position by the axial magnetic bearing (8) while rotating.

Then, the rotating body (1) is connected to an axial magnetic bearing.
While holding (8) and the radial magnetic bearings (5), (6) and rotating, the superconductor (22) is lowered to bring it back to the complete second superconducting state, Similarly, superconductors
(22) is raised, the weight of the rotating body (1) is supported only by the superconducting bearing (2), and the axial magnetic bearing (8) is deactivated. Thereby, the operation of the device by the superconducting bearing (2) is restarted, and the rotating body (1) is again supported by the superconducting bearing (2) and the radial magnetic bearings (5), (6) in the operating position and continues rotating. .

As described above, even if the magnetic levitation force due to the superconducting bearing (2) is reduced and the position of the rotating body (1) is lowered, the axial magnetic bearing (8) is used before the rotating body (1) touches down. The operation can be resumed while the rotating body (1) is kept rotating. Therefore, it is possible to operate continuously for a long time without touching down the rotating body (1).

In the above control process for preventing the lowering of the rotating body (1) by raising the elevating member (20) in order to keep the rotating body (1) at a predetermined operating position, the rotating body (1) during operation is controlled. If axial vibrations occur, actuate the axial magnetic bearings (8) during operation to suppress them,
It is also possible to control the electromagnets (8a) and (8b) by supplying a control current or a control current and a bias current smaller than a normal steady current. The generation of vibration in the axial direction of the rotating body (1) can be detected by the axial displacement sensor (7).

In the above-described superconducting bearing device, the rotating body (1) is supported in a non-contact manner by the radial magnetic bearings (5) and (6) and the axial magnetic bearing (8) when the operation is started or restarted. In this state, the superconductor (22) of the activated superconducting bearing (2) is raised, the weight of the rotating body (1) is supported by the superconducting bearing (2), and the axial magnetic bearing (8) is supported in the axial direction. Even after the force becomes zero, the axial magnetic bearing
Superconductor (22) to the position where a downward supporting force is generated at (8)
To raise the superconducting bearing (2) with a load greater than the weight of the rotating body (1), and then lower the superconductor (22) so that the bearing force of the axial magnetic bearing (8) becomes zero. At this point, since the superconductor (22) is stopped and the axial magnetic bearing (8) is in the inactive state, a pulley load is applied to the superconducting bearing (2) to generate magnetic flux creep that occurs at the beginning of operation. I'll let you do that. Therefore, in the initial stage of the operation start, the rotating body (1) does not drop due to magnetic flux creep and the superconductor (22) thereby does not suddenly rise, so that the superconductor (22) reaches the rising limit position The time until the rotating body (1) can be continuously supported by the superconducting bearing (2) becomes longer.

In the above embodiment, the second type superconductor (22)
Although a superconducting bearing (2) using a superconductor is used, a superconducting bearing using a first-class superconductor that appears in a first-class superconducting state by cooling can be used instead. In this case, the overall configuration of the superconducting bearing is the same as that of the above-described superconducting bearing (2), and the first type superconductor (22) is replaced with the first type superconductor (22).
Seed superconductors are used. The superconducting bearing using the first-class superconductor is a magnetic bearing of the rotating body (1) utilizing the complete diamagnetic phenomenon in the first-class superconducting state of the first-class superconductor. Receives only a supporting force in the axial direction upward from the superconductor, and is supported only in the axial direction. And the rotating body (1) is a radial magnetic bearing (5)
It is supported in the radial direction only by (6).

When a superconducting bearing using a first-class superconductor is used, the operation can be started in substantially the same manner as described above, and the magnetic levitation force of the superconducting bearing is reduced and the rotating body (1) Even if the position is lowered, the operation can be restarted without rotating the rotating body (1) without touching down.

At the start of operation, the rotating body (1) is mounted on the magnetic bearing (5).
(6) In the state where the superconductor is held at the operation position according to (8), the superconductor is cooled at the lower end position to cause the first type superconducting state to appear, and then the superconductor is gradually raised. When the superconductor approaches the permanent magnet (18) to some extent, the rotating body (1) receives an upward supporting force due to the complete diamagnetic phenomenon of the superconductor,
This supporting force increases with the rise of the superconductor, and conversely, the supporting force of the axial magnetic bearing gradually decreases. Then, even after the support force of the axial magnetic bearing (8) becomes zero and the entire weight of the rotating body (1) is supported by the superconducting bearing, a position where a downward supporting force is generated in the axial magnetic bearing (8) is generated. The superconductor is raised to a point where a load greater than the weight of the rotating body (1) is applied to the superconducting bearing, and then the superconductor is lowered, and when the supporting force of the axial magnetic bearing (8) becomes zero, The superconductor is stopped, the axial magnetic bearing (8) is deactivated, the rotating body (1) is supported in the operating position by the superconducting bearing and the radial magnetic bearings (5, 6), and the electric motor (9) is driven. And start driving.

During operation, if the magnetic levitation force of the superconducting bearing decreases with time and the position of the rotating body (1) gradually decreases from the operation position, the lifting member (20) and the superconductor are raised. Feedback control to keep the rotating body (1) in the operating position, and after the lifting member (20) cannot move up from the upper limit position, when the rotating body (1) falls below the lower limit position, the axial The magnetic bearing (8) is operated, and the rotating body (1) is again held in the operating position by the axial magnetic bearing (8). Then, with the rotating body (1) held and rotated by the axial magnetic bearings (8) and the radial magnetic bearings (5) and (6), the superconductor is lowered, and the complete first
After the superconducting state, the superconducting is raised, the weight of the rotating body (1) is supported only by the superconducting bearing, and the axial magnetic bearing (8) is deactivated, as in the above-described operation start.
Restart operation.

The configuration of the superconducting bearing, the axial magnetic bearing, the radial magnetic bearing, the electric motor and the like, and the overall configuration of the power storage device are not limited to those of the above-described embodiment, but can be changed as appropriate.

The present invention can be applied to a superconducting bearing device other than the power storage device.

FIG. 3 shows a second embodiment.

The superconducting bearing device of the second embodiment differs from the superconducting bearing device (4) in that the flywheels (13) and (14) are not provided.
Except that the configuration of (0) is different, it has the same configuration as the superconducting bearing device of the first embodiment. The electrical configuration of the superconducting bearing device of the second embodiment is the same as that of FIG. In the second embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals.

The superconducting magnetic bearing (40) includes an annular permanent magnet portion (41) concentrically fixed to the lower end of the rotating body (1) and an elevating member so as to face the permanent magnet portion (41) in the radial direction. (2
An annular superconductor portion (42) fixed to the upper end of (0).

A horizontal support disk (43) is fixed to the lower end of the rotating body (1), and a permanent magnet part (41) is fixed to the lower surface thereof. The permanent magnet portion (41) includes a vertical cylindrical support cylinder (44) fixed to the lower surface of the disk (43) so as to be concentric with the rotating body (1). On the inner circumference, a plurality of upper and lower annular permanent magnets (45) are arranged via an annular iron yoke (46), and are fixed by an annular locking member (47) fixed to the lower end surface of the support cylinder (44). . For example, each permanent magnet (45) has magnetic poles on both end surfaces in the axial direction, and the permanent magnets (45) vertically adjacent to each other are arranged so that the opposite magnetic poles have the same polarity.
(46) becomes the magnetic pole. The permanent magnet (45) is arranged concentrically with the rotating body (1), and the magnetic flux distribution of the permanent magnet (45) around the rotation axis of the rotating body (1) changes due to the rotation of the rotating body (1). Not to be done.

A horizontal support disk (48) is provided on the upper end of the elevating member (20).
Are fixed, and a superconductor portion (42) is fixed on the upper surface thereof. The superconductor section (42) includes an annular cooling tank (49) fixed to the upper surface of the disk (48) so as to be concentric with the rotating body (1). The tank (49) has a vertical and relatively tall double cylindrical shape, and an annular cooling space (49a) having a rectangular cross section passing through the axis is formed therein. Then, in a state where the elevating member (20) is raised to a predetermined position, the tank (49) enters the inside of the permanent magnet portion (41), and the tank (49)
The outer peripheral surface of (49) is opposed to the inner peripheral surface of the permanent magnet portion (41) at a slight interval.

A vertical cylindrical second-class superconductor (50) is fitted on the upper inside of the outer peripheral wall of the tank (49) so as to be concentric with the rotating body (1), and is disposed inside the cooling space (49a). It is fixed by a support member (51) arranged below the outer periphery. As the material of the superconductor (50), the same material as in the first embodiment is used. The outer peripheral surface of the superconductor (50) is in close contact with the inner surface of the outer peripheral wall of the tank (49), and when the lifting member (20) is raised to a predetermined position, the superconductor (50)
(49) is opposed to the permanent magnet (45) of the permanent magnet portion (41) through the thin outer peripheral wall and the annular minute gap, and is a separated position where a predetermined amount of magnetic flux of the permanent magnet (45) enters. Further, it is located at a position where the distribution of the invading magnetic flux does not change due to the rotation of the rotating body (1). The inner diameter of the superconductor (50) is the tank (49)
The outer diameter of the inner peripheral wall is considerably larger than the outer diameter of the inner peripheral wall, and a relatively large space is provided between the inner peripheral wall and the superconductor (50). Therefore, the inner peripheral surface of the superconductor (50) is completely exposed in the cooling space (49a).

The cooling fluid inflow hole (52) and the cooling fluid outflow hole (53) extend radially inward from the outer peripheral surface to the bottom wall of the tank (49), and then extend upward to pass through the upper surface of the bottom wall in the tank.
Are formed. The coolant supply pipe (23) is connected to the radially outer end of the horizontal portion of the inflow hole (52), and the upper end of the vertical portion of the inflow hole (41) on the upper surface of the bottom wall in the tank (49). The portion serves as a cooling fluid outlet (discharge port) (52a) from the inflow hole (52) to the cooling space (49a). The cooling fluid outlet (52a)
The lowermost portion in the cooling space (49) is located below the lowermost portion of the superconductor (50). A cooling fluid discharge pipe (24) is connected to a radially outer end of the horizontal portion of the outflow hole (53),
A lower end portion of a vertical cooling fluid suction pipe (54) is connected to a vertical portion of an outflow hole (53) that passes through an upper surface of a bottom wall in the tank (49). The upper end of the suction pipe (54) is slightly below the lower surface of the radially inner part of the top wall of the tank (49), and
It is located at almost the same height as or slightly above the height of the upper end of (9). The upper end of the suction pipe (54) in the tank (49) serves as a cooling fluid inlet (suction port) (54a) from the cooling space (49a) to the suction pipe (54).

With the same cooling device as in the first embodiment, liquid nitrogen as a cooling liquid is circulated through the cooling space (49a) of the tank (49) as follows, and fills the cooling space (49a). The superconductor (50) is cooled by the liquid nitrogen to be cooled.

The liquid nitrogen discharged from the cooling device is supplied to the supply pipe (23).
And the cooling space (49a) from the cooling fluid outlet (52a) through the inflow hole (52) and is filled in the cooling space (49a). The liquid nitrogen in the cooling space (49a) is
a) into the suction pipe (54), outflow hole (53) and discharge pipe (24)
Through to the cooling device. Part of the liquid nitrogen evaporates during the circulation as described above to become nitrogen gas, and part of the liquid nitrogen accumulates in the upper part of the cooling space (49a). However, when the bottom of the nitrogen gas layer is lowered to the level of the cooling fluid inlet (54a), the nitrogen gas flows from the cooling fluid inlet (54a) to the suction pipe (54).
Nitrogen gas enters the cooling fluid inlet (54
a) It does not collect below. That is, the nitrogen gas only accumulates in a slight uppermost portion in the cooling space (49a) above the cooling fluid inlet (54a). Since the cooling fluid inlet (54a) is located at substantially the same height as or above the uppermost part of the superconductor (50), no nitrogen gas accumulates around the superconductor (50). For this reason, superconductor (50)
Is filled with only liquid nitrogen, the superconductor (50) is always completely cooled by liquid nitrogen, and a good superconducting state is obtained. Further, since the superconductor (50) comes into contact with liquid nitrogen in a wide range including the entire inner peripheral surface and most of the lower end surface, the superconductor (50) can be efficiently cooled.

The starting method and the control method during operation of the superconducting bearing device in the second embodiment are the same as those in the first embodiment.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a superconducting bearing device of a power storage device according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing an example of an electrical configuration of the superconducting bearing device.

FIG. 3 is a schematic configuration diagram of a superconducting bearing device according to a second embodiment of the present invention.

[Explanation of symbols]

 (1) Rotating body (2) (40) Superconducting bearing (5) (6) Radial magnetic bearing (8) Axial magnetic bearing (9) Motor (18) (45) Permanent magnet (22) (50) Superconductor

Continued on front page F-term (reference) 3J102 AA01 BA03 BA17 BA18 BA19 CA21 DA09 DA10 DA16 DA22 DB05 DB10 DB11 FA24 GA06 GA07 GA09

Claims (2)

[Claims] A rotating body vertically arranged in a fixed portion;
A superconducting bearing that supports the rotating body at least in the axial direction and floats in a non-contact manner, a control-type radial magnetic bearing that supports the rotating body in a non-contact manner in the radial direction, and supports the rotating body in a non-contact manner in the axial direction as necessary. A control-type axial magnetic bearing, and an electric motor that rotationally drives the rotating body, wherein the superconducting bearing is provided on a permanent magnet attached to the rotating body, and the permanent magnet is provided on the fixed portion side so as to be movable up and down. A method for activating a superconducting magnetic bearing device comprising a superconductor which is opposed to the rotating magnetic body, wherein the radial magnetic bearing supports the rotating body at a predetermined position in a radial direction in a non-contact manner, and applies an upward supporting force to the axial magnetic bearing. The superconductor is brought into a superconducting state in a state where the rotating body is supported in a non-contact manner at a predetermined position in the axial direction by causing the rotation. After raising the superconductor to a position where the superconducting bearing generates an upward supporting force larger than the weight of the rotating body to generate a downward supporting force on the axial magnetic bearing, the supporting force of the axial magnetic bearing is increased. And lowering the axial magnetic bearing to a non-operating state, thereby starting the superconducting bearing device. 2. The superconductor of claim 2, wherein the superconductor has a second-class superconducting state by cooling, and in the second-class superconducting state, has the property of restraining an intruding magnetic flux and pinning the same. 2. The superconducting bearing according to claim 1, wherein the superconducting bearing supports the rotating body in a non-contact manner in an axial direction and a radial direction by a pinning force of the superconductor.
Method of starting a superconducting bearing device.