JP3113920B2 - Superconducting bearing device - 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 applied to a power storage device for converting surplus power into kinetic energy of a flywheel for storage.

[0002]

2. Description of the Related Art In this type of power storage device, conventionally,
Controlled magnetic bearing devices have been used.

[0003]

However, the control type magnetic bearing device has a problem that the control is complicated, and a control power supply, a detector, a control device, and the like are required, and the cost is increased.

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

[0005]

SUMMARY OF THE INVENTION A superconducting bearing device according to the present invention is capable of moving and rotating a fixed shaft having a cooling fluid passage in a direction of a rotation axis and a direction orthogonal to the direction of the rotation axis with respect to the fixed shaft. As described above, a cylindrical rotating body disposed around a fixed shaft, a superconducting bearing for rotatably supporting the rotating body in a non-contact state with respect to the fixed shaft, and a stator and a rotating body mounted on the fixed shaft. A drive source composed of a rotor and a cooling device that supplies a cooling fluid to the cooling fluid passage of the fixed shaft, such that the superconducting bearing faces a permanent magnet portion attached to the inner peripheral surface of the rotating body and the permanent magnet portion. The superconductor is mounted on a fixed shaft, and the superconductor is cooled by a cooling fluid sent to a cooling fluid passage of the fixed shaft by a cooling device.

[0006]

In the above-described superconducting bearing device, the magnetic flux of the permanent magnet penetrates the superconductor of the superconducting bearing and is pinned. Is held. In this state, it is possible to rotate the rotating body 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 state in the axial direction and the radial direction only by positioning the permanent magnet provided on the rotating body at a predetermined position relative to the superconductor. as a result,
There is no need to perform complicated control as in the case of the control type magnetic bearing device, and the control device is also inexpensive.

[0007] Since the permanent magnet is attached to the inner peripheral surface of the cylindrical rotating body, destruction of the permanent magnet due to centrifugal force can be prevented. Further, the superconductor can be cooled only by sending the cooling fluid to the cooling fluid passage of the fixed shaft by the cooling device.

[0008]

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

FIG. 1 schematically shows the entire configuration of a power storage device to which a superconducting bearing device is applied. This power storage device has a vacuum chamber (30) having a vertically fixed shaft (31) inside.
And a vertical cylindrical flywheel (cylindrical rotating body) (32) arranged around the fixed shaft (31) and rotatably supported in a non-contact state with the fixed shaft (31). Flywheel
(32) is made of high-tensile steel, and a through hole (33) is formed at the center thereof so as to penetrate it vertically.

An induction motor (3) for rotating a flywheel (32) at high speed in the upper and lower central portions in a vacuum chamber (30).
And superconducting bearings (34) and (35) for supporting the flywheel (32) in a non-contact state above and below it.

The electric motor (3) comprises a rotor (5) mounted on an inner peripheral surface of a through hole (33) of a flywheel (32), and a rotor (5).
(5) and a stator (6) mounted on a fixed shaft (31) via a horizontal disk (36).

The upper superconducting bearing (34) is constructed as follows. At the upper end of the inner peripheral surface of the through hole (33) of the flywheel (32), an annular permanent magnet (permanent magnet part) (37) is fixed on the fixed shaft (3).
Mounted concentrically with 1). The permanent magnet (37) is provided so that the magnetic flux distribution around the rotation axis of the flywheel (32) does not change due to rotation. Above and below the permanent magnet (37), a disk-shaped hollow cooling case is mounted on the fixed shaft (31).
(38) is provided in a fixed manner. A plurality of adjacent to each other in the circumferential direction on the lower surface of the lower wall of the upper case (38) and on the circumference concentric with the fixed shaft (31) on the upper surface of the upper wall of the lower case (38). The plate-shaped superconductor (17) is attached. The superconductor (17) is an yttrium-based high-temperature superconductor,
For example, it is made of a substrate made of YBa ₂ Cu ₃ O _x and uniformly mixed with normal conducting particles (Y ₂ Ba ₁ Cu ₁ ), and has a property of restricting the penetration of magnetic flux emitted from the permanent magnet (37). Things. The superconductor (17) is arranged at a separated position where the magnetic flux of the permanent magnet (37) enters by a predetermined amount and at a position where the distribution of the entering magnetic flux does not change due to the rotation of the flywheel (32).

The structure of the lower superconducting bearing (35) is the same as that of the upper superconducting bearing (34), and the same parts are denoted by the same reference numerals.

Case (38) of upper and lower superconducting bearings (34) (35)
Are communicated via a cooling fluid passage (39) formed in the fixed shaft (31). A cooling device (20) with a temperature control unit (19) provided below the vacuum chamber (30) is connected to the cooling fluid passage (39). And the cooling device (2
0), for example, a coolant such as liquid nitrogen is circulated through the cooling fluid passageway (39) and the case (38).
The superconductor (17) is cooled by the coolant filled in (38). As a result, the superconductor (17) enters a superconducting state, and much of the magnetic flux emitted from the permanent magnet (37) is
(17) is intruded and restrained (pinning phenomenon). Here, since the superconductor (17) has normal conductive particles uniformly mixed therein, the distribution of the magnetic flux penetrating into the superconductor (17) is constant, so that it is as if the superconductor (17) is standing. The permanent magnet (37) penetrates the provided virtual pin, and the flywheel (32) is restrained together with the permanent magnet (37) with respect to the superconductor (17). Therefore, the flywheel (32) is supported in the axial direction and the radial direction while being extremely stably levitated.

The lower surface of the flywheel (32) and the vacuum chamber
A touchdown bearing (21) made of a ceramic thrust ball bearing is provided concentrically with the flywheel (32) at opposing portions of the lower wall of the (30). Touchdown bearing
The upper raceway (22) of the (21) is fitted and fixed in an annular groove (40) formed concentrically on the lower surface of a portion near the outer periphery of the flywheel (32), and the lower raceway ( 23) is a vacuum chamber
(30) is arranged in an annular groove (42) formed on the upper surface of a base (41) fixed to the lower wall so as to face the groove (40) so as to be movable up and down and slightly movable in the radial direction. ing. Both races
A plurality of balls (24) are arranged between the track grooves (22a) and (23a) of (22) and (23). An elevating device (27) for raising and lowering the bearing ring (23) is provided below the bearing ring (23) in the groove (42).
The elevating device (27) is configured by, for example, arranging a plurality of piezoelectric elements in a stack. The superconductor (17) and the permanent magnet are moved by the touch-down bearing (21) and the elevating device (27).
An initial positioning mechanism for setting a relative position to (37) is configured.

During operation, if the superconductor (17) of the superconducting bearings (34) and (35) becomes normal conducting and loses the supporting force, the upper race of the touchdown bearing (21) The ball (2) located in the raceway (23a) of the lower race (23)
4), and the flywheel (32) is rotatably supported. For this reason, breakage of the flywheel (32) and its internal components is prevented.

During operation, the lifting / lowering device (27) is lowered to the lower operation position, and as described above, the superconducting bearings (34), (35)
The flywheel (32) is supported by
The upper race (22) is separated from the ball (24). The flywheel (32) rotates while being supported at substantially the center of the vacuum chamber (30), and the permanent magnets of the upper and lower superconductors (34) (35)
(37) are respectively supported at substantially the upper and lower centers of the upper and lower cases (38).

At the time of the stop, the supply of the coolant from the cooling device (20) is usually stopped. For this reason, the superconductor (17) is in a normal conducting state, and has no supporting force. For this reason, the flywheel (32) is stopped while being supported by the vacuum chamber (30) via the touchdown bearing (21).

The bearing device in such a stopped state is brought into an operating state as follows.

First, the lower bearing ring (23) of the touch-down bearing (21) is raised to an upper set position by the lifting device (27). When the bearing ring (23) rises, the ball (24) moves to both bearing rings (22).
The flywheel (3) contacts the track groove (22a) (23a) of (23).
2) is lifted up to position the lower case (38) of both superconductors (34) and (35) and the permanent magnet (37) in the vertical direction. (22) By the action of the raceway grooves (22a) (23a) and the ball (24) of (23), positioning in the radial direction is performed, and relative positioning between the flywheel (32) and the vacuum chamber (30) is performed. . At this time, the permanent magnet (37) approaches the lower surface of the upper case (38), and the upper case (3
The distance from the lower surface of 8) to the upper surface of the permanent magnet (37) is smaller than the distance from the upper surface of the lower case (38) to the lower surface of the permanent magnet (37).

When the flywheel (32) is positioned as described above, the coolant is circulated through the case (38) by the cooling device (20) to cool the superconductor (17). Superconductor (17)
When is cooled and enters a superconducting state, a supporting force is generated as described above. Therefore, the initial positioning device (27) is lowered to the operating position to eliminate the support. When the support force of the initial positioning device (27) is lost, the flywheel (32)
Is slightly lowered by its own weight, and stops at a position where it is balanced with the magnetic repulsive force and pinning force of the superconducting bearings (34) and (35). As a result, the permanent magnet (37) is supported substantially at the center of both cases (38) in the vertical direction, and the flywheel (32) is supported in a non-contact state as described above. )
To start operation.

[0022]

According to the superconducting bearing device of the present invention, as described above, a rotating body can be stably supported by a superconducting bearing having a simple structure, and the superconducting bearing has a complicated structure like a control type magnetic bearing device. There is no need to control. Also, the control device is inexpensive.

Since the permanent magnet is attached to the inner peripheral surface of the cylindrical rotating body, it is possible to prevent the permanent magnet from being broken by centrifugal force. Further, since the superconductor can be cooled only by sending the cooling fluid to the cooling fluid passage of the fixed shaft by the cooling fluid supply device, the structure for cooling the superconductor is simplified.

[Brief description of the drawings]

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

[Explanation of symbols]

 3 Induction motor (drive source) 5 Rotor 6 Stator 17 Superconductor 20 Cooling device 31 Fixed shaft 32 Flywheel (Rotating body) 34 Superconducting bearing 35 Superconducting bearing 37 Permanent magnet (permanent magnet part) 39 Cooling fluid passage

Claims (1)

(57) [Claims] 1. A fixed shaft having a cooling fluid passage, and a cylindrical member disposed around the fixed shaft so as to be able to move and rotate in a direction of a rotation axis and a direction perpendicular to the direction of the rotation axis with respect to the fixed shaft. A rotating body, a superconducting bearing for rotatably supporting the rotating body in a non-contact state with respect to the fixed shaft, a driving source including a stator mounted on the fixed shaft and a rotor mounted on the rotating body, and a cooling fluid for the fixed shaft A superconducting bearing comprises a permanent magnet portion attached to the inner peripheral surface of the rotating body and a superconductor attached to a fixed shaft so as to face the permanent magnet portion, A superconducting bearing device in which a superconductor is cooled by a cooling fluid sent to a cooling fluid passage of a fixed shaft by a cooling device.