JP6236723B2 - Vibration damping device and power storage device including vibration damping device - Google Patents

Description

  The present invention relates to a vibration damping device that can be applied to a power storage device using a superconductor and a flywheel and correct vibrations and displacements that occur on a rotating shaft.

2. Description of the Related Art Conventionally, there is known an electric power storage device that converts surplus power into kinetic energy of a flywheel and stores it, and converts kinetic energy stored in the flywheel into electric energy when necessary to take out.
As shown in Patent Document 1, the power storage device includes a rotating body including a flywheel, a rotating shaft fixed to the flywheel, and a non-contact torque transmitting component connected to the rotating shaft. The rotating shaft of the rotating body is supported in a non-contact state by a magnetic support device having a superconductor.

JP 2010-239796 A

By the way, in the power storage device configured as described above, a flywheel is placed in a high vacuum environment for energy conservation and heat insulation, and a magnetic support device having a superconductor is used as a bearing for a rotating shaft. The frictional resistance is kept to a minimum.
Here, since the above power storage device uses a magnetic support device having a superconductor, there is theoretically no element that attenuates the stored kinetic energy by rotating the flyhole.
However, on the other hand, if eccentric vibration occurs on the rotating shaft of the flywheel for some reason, it is difficult to attenuate this eccentric vibration.

  Such vibration of the rotating shaft of the flywheel may continuously increase due to resonance near the natural frequency determined by the spring constant of the superconducting magnetic bearing supporting the rotor and the rigidity of the rotor. Here, if the attenuation is 0, vibration may diverge. In a rotor supported by a normal mechanical bearing, there is a damping due to the friction of the mechanical bearing, a damper can be added at room temperature, and a controlled magnetic bearing (AMB) using normal conduction. In the rotor supported by (3), damping can be given by control. However, in superconducting magnetic bearings, in principle, there is no damping. However, in the case of actual occurrence, superconducting magnetic bearings are limited to use at extremely low temperatures and high vacuums. There was also a problem that it could not be dealt with.

  The present invention has been made in view of the above-described circumstances, and when eccentric vibration occurs in the rotating shaft of the flywheel under extremely low temperature and high vacuum, the eccentric vibration is effectively damped, and thereby the eccentric vibration. Provided is a vibration damping device and a power storage device including the vibration damping device that can prevent the device from being broken due to the above and wasteful consumption of the kinetic energy accumulated in the flywheel.

In order to solve the above problems, the present invention proposes the following means.
The present invention provides a rotating magnet that rotates integrally with a rotating shaft, and is disposed on the fixed member side, and is disposed so as to face the rotating magnet with an interval in the axial direction of the rotating shaft. And a conductor plate that generates eddy currents by rotation displaced from the center of the shaft.

  Further, the present invention comprises a conductor plate that rotates integrally with the rotating shaft, and a fixed magnet that is disposed on the fixed member side and is disposed so as to be opposed to each other with an interval in the axial direction of the rotating shaft, The conductor plate generates an eddy current by rotating with respect to the fixed magnet with the rotation axis displaced.

According to the vibration damping device of the present invention, the conductor plate that generates the eddy current due to the rotation displaced from the center of the rotating shaft is provided. Therefore, the energy of the eccentric vibration generated in the rotating shaft is converted into the eddy current generated by the conductor plate. And the eccentric vibration can be effectively damped.
In addition, by applying the vibration damping device of the present invention to a power storage device using a flywheel, it is possible to prevent the device from being destroyed by eccentric vibration, and the kinetic energy accumulated in the flywheel is the flywheel. It is possible to prevent wasteful consumption due to the eccentric vibration generated on the rotating shaft of the wheel.
In addition, the vibration damping device of the present invention is simple in that it can attenuate the eccentric vibration generated in the rotating shaft by providing a conductor plate that generates eddy current on the fixed member side and providing a magnet corresponding to the conductor plate. Since it is a structure, it can also be easily installed in a power storage device or the like used under extremely low temperature and high vacuum.

1 is an overall view of a power storage device 1 according to Embodiment 1 of the present invention. It is a schematic block diagram of the vibration damping device 20 applied to the power storage device 1 of FIG. 3 is a graph showing a relationship between an interval formed in the vibration damping device 20 and a damping coefficient. It is a general view of the electric power storage apparatus 100 which concerns on Embodiment 2 of this invention.

(Embodiment 1)
Embodiment 1 of the present invention will be described with reference to FIGS.
FIG. 1 is a testing machine of a power storage device 1 to which the present invention is applied, and has a function of storing kinetic energy in a flywheel that is an internal rotating body.

The power storage device 1 is, for example, a superconducting flywheel power storage device that supports a rotating body by a magnetic support device using a superconductor and stores electric power as kinetic energy of the rotating body.
For this reason, the electric power storage device 1 converts and stores surplus power into kinetic energy of the flywheel F during charging, and converts the kinetic energy accumulated in the flywheel F into electric energy during discharge. Should have. However, since this apparatus is created as a test machine, the motor generator for rotating the flywheel F or generating electric power from the rotation is omitted.
Specifically, the power storage device 1 according to the present embodiment mainly includes a rotating shaft M, a flywheel F, superconducting magnetic bearings 9, 10, a vacuum vessel 11 serving as an inner tank, a cooling device 12, The vibration evacuation device 13 is provided, and a vibration damping device 20 according to the present invention is provided at the position of the upper end portion of the rotation shaft M.

  The rotation axis M is a member that rotates integrally with the flywheel F. The flywheel F is a member for storing electrical energy as kinetic energy. The flywheel F is fixed to the rotation axis M so that the center of the flywheel F coincides with the center axis O of the rotation axis M. The flywheel F is housed in a floating state in the vacuum vessel 11 together with the rotating shaft M, and functions as a superconducting flywheel for storing power.

The superconducting magnetic bearings 9 and 10 are devices that rotatably support the rotating shaft M. The superconducting magnetic bearing 9 is disposed below the flywheel F1 and supports the upper end portion of the rotating shaft M in a non-contact manner. The superconducting magnetic bearing 10 is disposed below the flywheel F and supports the lower end side of the rotating shaft M in a non-contact manner. The superconducting magnetic bearings 9 and 10 function as thrust bearings that rotatably support the rotating shaft M by utilizing the magnetic levitation due to the Meissner effect or complete diamagnetism of the superconducting material. The superconducting magnetic bearings 9 and 10 include superconducting bulk bodies (rotors) 9a and 10a, superconducting coils (stators) 9b and 10b, etc., and the superconducting bulk bodies 9a and 10a on the rotating body side and the superconducting coil 9b on the stationary body side. 10b, a magnetic field is generated. The superconducting magnetic bearings 9 and 10 make the superconducting bulk bodies 9a and 10a and the superconducting coils 9b and 10b generate a magnetic repulsive force between the superconducting bulk bodies 9a and 10a and the superconducting coils 9b and 10b. The rotating shaft M is guided so that a predetermined interval is maintained during the interval. The superconducting magnetic bearings 9 and 10 support the rotating shaft M and the flywheel F in a levitated state, thereby reducing the frictional resistance of the bearing portion that occupies most of the energy loss.

  The superconducting bulk bodies 9a and 10a are a mass of high-temperature superconducting material having superconducting characteristics equivalent to those of a single crystal. The superconducting bulk bodies 9a and 10a are, for example, melt-grown bodies obtained by crystal growth after dissolving a Y-based superconducting material, and exhibit superconducting characteristics when cooled.

  The vacuum container 11 is a container having a cryogenic temperature / high vacuum inside and accommodates the superconducting magnetic bearings 9 and 10 while supporting the superconducting coils 9b and 10b of the superconducting magnetic bearings 9 and 10. The vacuum vessel 11 is maintained at a very low temperature so that the superconducting coils 9b and 10b of the superconducting magnetic bearings 9 and 10 are kept below the critical temperature, and also reduces windage loss of the flywheel F. The interior is maintained under high vacuum.

  The cooling device 12 is a device that cools the inside of the inner tank 1, for example, a cryogenic temperature that cools the superconducting coils 9 b and 10 b of the superconducting magnetic bearings 9 and 10 in the vacuum vessel 11 to a critical temperature or lower with liquid nitrogen. It is a heat conduction type cooling device such as an industrial refrigerator. The cooling device 12 includes a refrigerator 12a such as a GM (Gifford-McMahon) refrigerator that repeatedly cools and compresses helium gas, and a compressor 12b that supplies refrigerant gas to the refrigerator 12a. And a refrigerant supply rod 12c for supplying refrigerant gas having passed through the refrigerator 12a and the compressor 12b.

  The vacuum evacuation device 13 is a device that evacuates the inside of the vacuum vessel 11 and transfers heat to the superconducting bulk bodies 9a and 10a (the superconducting bulk bodies 9a and 10a are cooled by cold heat from the superconducting coils 9b and 10b) Therefore, the inside of the vacuum vessel 11 is adjusted to a vacuum state of about several to 100 Pa. The evacuation device 13 includes a vacuum pump 13 a that evacuates the inside of the vacuum vessel 11, a pipe line 13 b that connects the vacuum pump 13 a and the vacuum vessel 11, and the like.

Next, the vibration damping device 20 installed at the upper end position of the rotation shaft M will be described in detail with reference to FIGS.
As shown in FIG. 2, the vibration damping device 20 is disposed on the side of a rotating member 21 </ b> A that rotates integrally with the rotating shaft M and a fixed member that forms a part of the vacuum vessel 11, and is spaced in the axial direction of the rotating shaft M. The fixed magnet 21B is disposed so as to face the rotating magnet 21A, and is disposed so as to face the rotating magnet 21A with an interval in the axial direction of the rotating shaft M. And a conductor plate 22 that generates an eddy current by rotation displaced from the central axis O of the rotation axis M.
As the conductor plate 22, a good conductor such as silver or aluminum is used in addition to copper. Further, in this example, the rotating magnet 21A and the conductor plate 22 are arranged in a positional relationship directly facing each other with an interval in the axial direction of the rotating shaft M.

In the vibration damping device 20 configured as described above, since the magnetic field change does not occur on the conductor plate 22 while the rotating magnet 21A rotates without rotating in the radial direction together with the rotating shaft M, an eddy current is not generated. And no rotational energy loss occurs.
On the other hand, when the rotating magnet 21A vibrates in the radial direction together with the rotating shaft M and a magnetic field is generated on the conductor plate 22, an eddy current flows in a direction to cancel the rotating magnet M, and the rotating shaft M vibrates due to the eddy current. It is suppressed. At this time, since a finite electrical resistance exists in the conductor plate 22, the eddy current generated here is attenuated, whereby the vibration of the rotating shaft M is attenuated and converged.

FIG. 3 shows the result of measuring the damping coefficient of the vibration damping device 20 based on this principle.
Here, the attenuation coefficient is measured when the distance between the rotating magnet 21A on the rotating side and the conductor plate 22 on the fixed side is changed. As can be seen from FIG. 3, it can be seen that the attenuation coefficient tends to increase as the distance between the rotating magnet 21A on the rotating side and the conductor plate 22 on the fixed side decreases. In addition, the measurement here is performed at room temperature, but when it is performed under 77K (liquid nitrogen immersion), the electrical resistance becomes small, so the attenuation coefficient is expected to increase by about 1.5 times. Is done.
In addition, when a rotation test was performed at room temperature and under vacuum using a small system verification model rotor, if there is no vibration damping device 20 according to the present embodiment, a primary critical speed (a predetermined threshold value) Rotational speed) increased in amplitude, and no further measurement was possible. On the other hand, when three sets of vibration damping devices 20 according to the present embodiment were attached and a rotation test was performed under the same room temperature and vacuum as described above, the amplitude was reduced, and after balancing several degrees, 1 The rotation axis M can be rotated up to 3000 rotations per minute beyond the second and second critical speeds, and the effectiveness of the vibration damping device 20 according to the present embodiment could be confirmed.

As described in detail above, according to the vibration damping device 20 of the power storage device 1 according to the present embodiment, the conductor plate 22 that generates eddy current by the rotation displaced from the central axis O of the rotation axis M is provided. The energy of the eccentric vibration generated in the rotating shaft M can be released by the eddy current generated in the conductor plate 22, and the eccentric vibration can be effectively damped.
Further, by applying the vibration damping device 20 to the power storage device 1 using the flywheel F, the power storage device 1 is prevented from being destroyed, and the kinetic energy accumulated in the flywheel F is It is possible to prevent wasteful consumption due to the eccentric vibration generated on the rotation axis M of F.

In the above embodiment, the conductor plate 22 is disposed on the fixed member side of the vacuum vessel 11 facing the rotary magnet 21A with an interval in the axial direction of the rotation axis M. In addition to this, FIG. As shown, the conductor plate 23 may be provided also on the rotating magnet 21A side, and the eddy current may be generated in the conductor plate 23 to similarly effectively attenuate the eccentric vibration.
Further, in the above embodiment, the conductor plate 22 on the fixed magnet 21B side may be omitted, and the eddy current may be generated only in the conductor plate 23 on the rotating magnet 21A side shown in FIG.

(Embodiment 2)
A second embodiment of the present invention will be described with reference to FIG.
The power storage device 100 shown in the second embodiment is different from the power storage device 1 (tester) shown in the first embodiment in that it has a motor generator 2.
The motor generator 2 converts surplus power into kinetic energy of the flywheel F during charging, and converts kinetic energy stored in the flywheel F into electric energy during discharging.
Specifically, the power storage device 100 of Embodiment 2 includes a motor generator 2, a gantry 3, a joint 4, a connecting shaft 5, a magnetic clutch 6, a rotating shaft M, a flywheel F, and superconductivity. The structure includes a magnetic bearing 9, 10, a vacuum vessel 11 serving as an inner tank, a cooling device 12, and a vacuum exhaust device 13, and the vibration damping device 20 according to the present invention is located at the end position of the rotating shaft M. Is provided.
Among these components, the rotating shaft M, the flywheel F, the superconducting magnetic bearings 9 and 10, the vacuum vessel 11 serving as the inner tank, the cooling device 12, the vacuum exhaust device 13, and the vibration damping device. Since 20 has the same configuration as that of the first embodiment, duplicate description thereof is omitted in the second embodiment.

The motor generator 2 is a device in which the motor and the generator are reversible and are used together. The motor generator 2 rotates the electric motor with electric energy to rotate the flywheel F, and generates electric power by rotating the generator with the kinetic energy of the flywheel F. The motor generator 2 includes a rotating shaft 2a and the like.
The joint 4 is a device that connects the rotating shaft 2a on the motor generator 2 side and the connecting shaft 5 on the magnetic clutch 6 side. The joint 4 is, for example, a shaft joint that transmits power between the motor generator 2 and the magnetic clutch 6. The connecting shaft 5 is a member that connects the joint 4 and the magnetic clutch 6. One end of the connecting shaft 5 is fixed to the joint 4 so as to rotate together with the joint 4 and the magnetic clutch 6, and the other end is fixed to the clutch piece 6 a of the magnetic clutch 6. Yes.

The motor generator 2 is a device in which the motor and the generator are reversible and are used together. The motor generator 2 rotates the electric motor with electric energy to rotate the flywheel F, and generates electric power by rotating the generator with the kinetic energy of the flywheel F. The motor generator 2 includes a rotating shaft 2a and the like.
The joint 4 is a device that connects the rotating shaft 2a on the motor generator 2 side and the connecting shaft 5 on the magnetic clutch 6 side. The joint 4 is, for example, a shaft joint that transmits power between the motor generator 2 and the magnetic clutch 6. The connecting shaft 5 is a member that connects the joint 4 and the magnetic clutch 6. One end of the connecting shaft 5 is fixed to the joint 4 so as to rotate together with the joint 4 and the magnetic clutch 6, and the other end is fixed to the clutch piece 6 a of the magnetic clutch 6. Yes.

  The magnetic clutch 6 is a device that transmits power between the motor generator 2 and the rotating shaft M. The magnetic clutch 6 is a magnetic force torque transmission component such as a non-contact magnetic clutch that interrupts power in a non-contact manner. The magnetic clutch 6 includes a clutch piece 6a of a permanent magnetic material or a coil (for example, copper wire) and a clutch piece 6b of a permanent magnetic material that generates a magnetic force between the clutch piece 6a. In the magnetic clutch 6, the clutch piece 6a and the clutch piece 6b are opposed to each other so as to form a gap between the clutch piece 6a and the clutch piece 6b, and the clutch piece 6a is disposed outside the vacuum vessel 11, A clutch piece 6 b is disposed inside the vacuum container 11.

As described in the first embodiment, the vibration damping device 20 includes a rotating magnet 21A that rotates integrally with the rotating shaft M, and a rotating shaft M that is disposed on the side of the vacuum vessel 11 serving as a fixed member and that rotates with respect to the rotating magnet 21A . The conductor plate 22 is disposed so as to be opposed to each other with an interval in the axial direction, and generates an eddy current by rotation displaced from the central axis O of the rotation axis M.

In the first embodiment, the vibration damping device 20 is arranged at the upper and lower ends of the flywheel F. However, in this second embodiment, the vibration damping device 20 is provided with the magnetic clutch 6 in order to suppress vibration due to the transmission force of the clutch. It is also placed directly below.
At this time, in order to secure the installation space of the vibration damping device 20, the rotating magnet 21 </ b> A on the rotation side and the conductor plate 22 on the fixed side are both formed in an annular shape so as to surround the rotating shaft M.

In the vibration damping device 20 configured as described above, since the magnetic field change does not occur on the conductor plate 22 while the rotating magnet 21A rotates without rotating in the radial direction together with the rotating shaft M, an eddy current is not generated. And no rotational energy loss occurs.
On the other hand, when the rotating magnet 21A vibrates in the radial direction together with the rotating shaft M and a magnetic field is generated on the conductor plate 22, an eddy current flows in a direction to cancel the rotating magnet M, and the rotating shaft M vibrates due to the eddy current. It is suppressed. At this time, since a finite electrical resistance exists in the conductor plate 22, the eddy current generated here is attenuated, whereby the vibration of the rotating shaft M is attenuated and converged.

In the vibration damping device 20 configured as described above, since the magnetic field change does not occur on the conductor plate 22 while the rotating magnet 21A rotates without rotating in the radial direction together with the rotating shaft M, an eddy current is not generated. And no rotational energy loss occurs.
On the other hand, when the rotating magnet 21A vibrates in the radial direction together with the rotating shaft M and a magnetic field is generated on the conductor plate 22, an eddy current flows in a direction to cancel the rotating magnet M, and the rotating shaft M vibrates due to the eddy current. It is suppressed. At this time, since a finite electrical resistance exists in the conductor plate 22, the eddy current generated here is attenuated, whereby the vibration of the rotating shaft M is attenuated and converged.

In the second embodiment as well, the conductor plate 22 is disposed on the fixed member side of the vacuum vessel 11 facing the rotary magnet 21A with an interval in the axial direction of the rotation axis M. 2, a conductor plate 23 is also provided on the rotating magnet 21 </ b> A side as shown in FIG. 2, and an eddy current is also generated in the conductor plate 23, so that eccentric vibration can be effectively damped in the same manner. good.
In the above embodiment, the conductor plate 22 on the fixed magnet 21B side may be omitted, and the eddy current may be generated only in the conductor plate 23 on the rotating magnet 21A side to attenuate the eccentric vibration.

  Further, the vibration damping device 20 shown in the first and second embodiments is applied to the power storage devices 1 and 100, but is not limited to this, and a motor or a generator that may cause eccentric vibration in the rotating body. It may be applied to a rotating device such as a compressor.

  As mentioned above, although embodiment of this invention was explained in full detail with reference to drawings, the concrete structure is not restricted to this embodiment, The design change etc. of the range which does not deviate from the summary of this invention are included.

  The present invention relates to a vibration damping device that is applied to a power storage device that uses a superconductor and a flywheel, and that can correct vibration and displacement generated on a rotating shaft.

1 Power storage device 9 Superconducting magnetic bearing 10 Superconducting magnetic bearing 11 Vacuum container (fixing member)
20 Vibration damping device 21A Rotating magnet 21B Fixed magnet 22 Conductor plate 23 Conductor plate 100 Power storage device F Flywheel M Rotating shaft O Center shaft

Claims (5)

A rotating magnet that rotates integrally with the rotating shaft;
A conductor plate disposed on the fixed member side and disposed to face the rotating magnet at an interval in the axial direction of the rotating shaft, and generates a eddy current by rotation displaced from the center of the rotating shaft; , comprising a,
The fixed member is further provided with a fixed magnet for causing a magnetic force to act on the rotating magnet together with the conductor plate, with an interval in the axial direction between the rotating magnet ,
The conductor plate is a vibration damping device provided at a position between the rotating magnet and the fixed magnet . The vibration damping device according to claim 1, wherein the conductor plate extends to a position radially outward of the fixed magnet . A conductor plate that rotates integrally with the rotating shaft;
A fixed magnet disposed on the fixed member side and disposed so as to face each other with an interval in the axial direction of the rotating shaft,
The conductor plate generates an eddy current by performing rotation in which the rotation shaft is displaced with respect to the fixed magnet,
The rotating shaft is further provided with a rotating magnet that causes a magnetic force to act on the fixed magnet together with the conductor plate, with an interval in the axial direction between the rotating magnet,
The conductor plate is a vibration damping device provided at a position between the fixed magnet and the rotating magnet . The vibration damping device according to claim 3, wherein the conductor plate extends to a position radially inward of the rotary magnet .   By installing a flywheel on the rotating shaft of the vibration damping device according to any one of claims 1 to 4, and rotating the flywheel under a cryogenic temperature and a high vacuum via a superconducting magnetic bearing, A power storage device that stores electrical energy as kinetic energy.

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