JPH11150911A - Flywheel energy storage - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flywheel energy storage which eliminates influence of running vibration, yawing, pitching, etc., at the time of being loaded on a self-running machine such as an electric motorcar, etc. SOLUTION: A rotary shaft 14 is arranged vertically within a device housing 9, and a discoidal flywheel 2 is integrated with the bottom of the rotary shaft 14. The rotary shaft 14 is supported rotatably by an upper ball bearing 16 and a lower ball bearing 17 of roller bearings, and a magnetic ball bearing 1 of a magnetic energizing means. The magnetic bearing 1 is a passive thrust magnetic bearing which constitutes a magnetic circuit of a magnetic rotor 25 and a magnetic stator 26, and it energizes the rotary shaft 14 upward with the energizing force corresponding to the weight of the rotary shaft 14, the flywheel 2, etc., and the pre-load of the lower ball bearing 17. Moreover, damping rings 19 and 20 of vibration attenuating means having large rigidity and an attenuating function are interposed between the device housing 9 and both ball bearings 16 and 17.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flywheel energy storage device for storing electric energy as kinetic energy, and more particularly to a device for controlling running vibration, yawing, pitching and the like when mounted on a self-propelled machine such as an electric vehicle. Related to the technology to eliminate the effects.

[0002]

2. Description of the Related Art In recent years, electric vehicles have attracted worldwide attention because they do not emit harmful exhaust gases such as CO and NOx, and have no exhaust noise or engine vibration. Research and development are being actively pursued.
In an electric vehicle, a driving motor is rotated by electricity stored in a storage battery, and the rotational power is transmitted to traveling wheels, so that the storage capacity of the storage battery is substantially proportional to the traveling distance. However, since storage batteries are very heavy and large in volume, if they are installed in large quantities to increase the mileage per charge, the weight and size of the entire electric vehicle will increase, as will space for occupants and cargo. It becomes difficult to secure.

[0003] A flywheel energy storage device (hereinafter abbreviated as flywheel device) is a device that suppresses power consumption when an electric vehicle travels in a city or the like and realizes long-distance traveling with a relatively small capacity storage battery. Is attracting attention. A flywheel device is a device in which a large mass flywheel is rotatably held in a device housing, and converts electrical energy supplied from an external device into rotational energy of the flywheel and temporarily stores the energy. The rotational energy of the wheel is converted back to electric energy and supplied to an external device.

For example, in an electric vehicle, in order to recover kinetic energy of a vehicle body during braking, a braking generator is driven via a power transmission device or the like to obtain electric energy, and then the electric energy is used as a flywheel device. To convert the flywheel at a high speed. At the time of starting or accelerating, the kinetic energy of the flywheel is converted into electric energy by the energy conversion means, and the driving motor is rotated by the obtained electric energy. This allows
Even in the city where the vehicle frequently starts and stops, the energy discarded by braking is reduced, and the power consumption can be extremely reduced.

Japanese Patent Application Laid-Open No. 61-94532 discloses FIG.
As shown in FIG. 1, an example of a conventional flywheel device is disclosed. In FIG. 1, a flywheel 2 having a large mass is supported by a magnetic bearing 1 at an upper part and by a pivot bearing 4 fluid-lubricated at a lower part. In the cylindrical portion 5 of the flywheel 2,
A generator motor 8 including the rotor 6 and the stator 7 is formed. The outer diameter of the flywheel 2 is largest at the upper part. In this flywheel device, the upper magnetic bearing 1 attracts the rotating shaft 2 upward by magnetic force, whereby the proportion of the weight of the flywheel 2 that the lower pivot bearing 4 bears is reduced, resulting in excessive thrust. Damage to the pivot bearing 4 due to the load is prevented.

[0006]

By the way, this type of flywheel device, when actually mounted on an electric vehicle, has a desired performance in a relatively short period of time due to road conditions, driving modes, and the like. In some cases, it could not be demonstrated. For example,
When the electric vehicle travels on a rough road, makes a sharp turn, or performs a sudden braking, the flywheel 2 is subjected to severe vertical vibrations or an excessively large yaw moment, so that appropriate fluid lubrication at the pivot bearing 4 cannot be maintained. Sometimes. That is, when the lubricating oil surface of the spherical shaft end or the spherical cradle constituting the pivot bearing 4 is destroyed by excessive stress due to vibration, yaw moment, or the like, the portion is brought into boundary lubrication or metal contact. In such a case, damage such as rapid wear and seizure occurs in the pivot bearing 4, and the smooth rotation of the flywheel 2 is hindered, or the flywheel 2 does not rotate at all, and the kinetic energy is lost. Storage is no longer possible. The present invention has been made in view of the above circumstances, and has as its object to provide a flywheel energy storage device that eliminates the effects of running vibration, yawing, and pitching when mounted on a self-propelled machine such as an electric vehicle. .

[0007]

According to the present invention, there is provided a rotary shaft arranged substantially vertically to an apparatus housing, a flywheel integrated with the rotary shaft, and And energy conversion means for conversion between kinetic energy and, in a flywheel energy storage device that stores electric energy supplied from the outside as rotational energy of the flywheel, At least a pair of upper and lower rolling bearings provided for rotatably supporting the rotating shaft, and the rotating shaft or the flywheel to bear the weight of the rotating shaft and the flywheel and the preload of the rolling bearing. Magnetic urging means for urging the upper part upward, and a vibration damping hand interposed between the device housing and the rolling bearing. To propose a thing with a door.

According to the flywheel energy storage device of the present invention, the rotating shaft and the flywheel are pulled up and down by the urging force of the magnetic urging means and the axial fixing force based on the preload of the lower rolling bearing. Because it is supported, it is supported by the rolling bearing in a stable state not only at rest but also during rotation. Also, even if excessive vibration or yaw moment acts on the device housing, it becomes difficult for these to be transmitted to the rolling bearing and the rotating shaft by the action of the vibration damping means, and the rolling bearing is damaged due to the destruction of the lubricating oil film and the like. Disappears.

[0009]

FIG. 1 shows a flywheel device according to a first embodiment of the present invention in a longitudinal sectional view. This flywheel device is manufactured as a regenerative brake for an electric vehicle. The flywheel device converts the electrical energy input from the braking generator into kinetic energy for the flywheel and stores it. Is converted into electric energy and supplied to the driving motor.

The outer shell of the flywheel device is formed by a hollow device housing 9. A pair of pivots 10 are fixed to the outer peripheral surface of the device housing 9 at an interval of 180 °, and these pivots 10 are rotatably mounted on a pair of support arms 12 of the first support frame 11 via bearings 13. Supported. Further, the first support frame 11 has a pair of pivots (not shown) in a direction orthogonal to the pivot 10, and these pivots are rotatably supported by the second support frame (not shown). That is, in the present embodiment, the first support frame 11 and the second
A gimbal mechanism is formed with the support frame, and the center axis of the device housing 9 is always kept vertical regardless of the change in the posture of the electric vehicle.

A rotary shaft 14 is disposed vertically in the apparatus housing 9, and a disc-shaped flywheel 2 is integrated below the rotary shaft 14. Flywheel 2
Is made of a metal such as steel or an aluminum alloy or a fiber-reinforced plastic, and increases the moment of rotation by increasing the thickness of the outer peripheral portion, thereby storing large kinetic energy. In the figure, 32
Is a support bracket for fixing the flywheel 2 to the rotating shaft 14. In this embodiment, the flywheel 2
The interior of the apparatus housing 9 is evacuated to reduce the frictional resistance between the air and the air.

The rotating shaft 14 is rotatably supported by an upper ball bearing 16 and a lower ball bearing 17 as rolling bearings (both are deep groove ball bearings in the present embodiment) and the magnetic bearing 1 as magnetic biasing means. I have. Further, damping rings 19, 20 as vibration damping means are interposed between the device housing 9 and the two ball bearings 16, 17, respectively. Both damping rings 19 and 20 have high rigidity and high damping ability. In the present embodiment, a so-called fiber reinforced resin or the like in which carbon fiber, glass fiber, or metal fiber is contained in a synthetic resin is used as a material. I have. Although the damping ring 20 is fixed to both the lower ball bearing 17 and the device housing 9, the damping ring 19 is fixed only to the upper ball bearing 16, and expands and contracts due to thermal expansion of the rotating shaft 14. It is slidable up and down with respect to the device housing 9 to allow it. In the figure, 21 is a double ball bearing 16,
17 is a nut for fastening the inner ring 17 to the rotating shaft 14.

The magnetic bearing 1 includes a magnetic rotor 25 fixed to the upper end of the rotating shaft 14 and a magnetic stator 26 fixed to the lower surface of the upper lid 29 of the device housing 9. The magnetic rotor 25 is a disk made of a magnetic material made of ferrite or the like. The magnetic stator 26 has a ring-shaped permanent magnet 27 and an axial magnetic material fixed to a magnetic pole on the lower surface of the permanent magnet 27. It comprises a core-side yoke 51 and an outer-peripheral-side yoke 52 which is an annular magnetic body having an L-shaped cross-section and fixed to a magnetic pole on the upper surface of the permanent magnet 27.

The magnetic stator 26 has an inverted U-shaped cross section, and the magnetic stator 26
The density of the magnetic flux flowing to the S pole of the permanent magnet through the magnetic rotor 25 and the magnetic rotor 25 is increased. That is, the magnetic bearing 1 is a passive thrust magnetic bearing that forms a magnetic circuit with the magnetic rotor 25 and the magnetic stator 26. In the case of the present embodiment,
Weight of the rotating shaft 14, the flywheel 2, etc. and the lower ball bearing 1
The urging force corresponding to the preload of No. 7 urges the rotating shaft 14 upward. On the lower surface 26a of the magnetic stator 26 and the upper surface 25a of the magnetic rotor 25, a plurality of annular grooves are formed in such a manner that mutual peaks face each other. Since the magnetic flux flows from peak to peak, even if a radial load acts on the rotating shaft 14, the flowing magnetic flux prevents separation between the peaks. As a result, a radial centripetal force is generated on the rotating shaft 14, which makes it difficult for the rotating shaft 14 to be displaced in the radial direction with respect to the device housing 9. Become.

In the present embodiment, a generator motor 8 as an energy conversion means is provided between the magnetic bearing 1 and the flywheel 2. The generator motor 8 includes a stator 7 fixed to a device housing 9 and a rotor 6 fixed to a rotating shaft 14. The inner peripheral surface of the stator 7 and the outer peripheral surface of the rotor 6 face each other. Then, when electric energy from a braking generator or the like of the electric vehicle is supplied to the stator 7, the generator motor 8 functions as a motor and rotates the rotating shaft 14 and the flywheel 2. When starting or accelerating, the generator motor 8 functions as a generator,
The electric energy extracted from the stator 7 is supplied to a driving motor of the electric vehicle.

Hereinafter, the operation of the present embodiment will be described. The body of the electric vehicle changes its posture when traveling uphill or turning, but the center axis of the flywheel device (that is, the rotation axis 1) is changed.
4 is always kept vertical by the gyro effect of the flywheel 2 because the device housing 9 is supported via the gimbal mechanism. Accordingly, the weight of the flywheel 2 and the rotating shaft 14 is borne by the magnetic bearing 1, so that the two ball bearings 16 and 17 are connected to the rotating shaft 1.
Only the radial support 4 need be performed.

On the other hand, when the electric vehicle travels on a rough road, makes a sharp turn, or makes a sudden braking, a severe vertical vibration or an excessive yaw moment acts on the device housing 9 and the rotating shaft 14. The resulting stress acts on the supporting portion of the rotating shaft 14. However, in this embodiment,
Since the damping rings 19, 20 are interposed between the device housing 9 and the two ball bearings 16, 17, stable high-speed rotation can be realized, and relative vibration, yaw moment, etc. It is absorbed and attenuated by 20 and hardly acts on both ball bearings 16 and 17.
Therefore, in the two ball bearings 16 and 17, rapid wear and seizure due to the destruction of the lubricating oil film and the like do not occur.
The smooth support of the rotating shaft 14 is not hindered. As a result, the energy storage performance of the flywheel device can be maintained for a long time, and the maintenance interval can be lengthened.

FIG. 2 shows a flywheel device according to a second embodiment of the present invention in a longitudinal sectional view. This flywheel device generally adopts the same configuration as that of the first embodiment, except that a preload spring 30 is interposed between the device housing 9 and the upper ball bearing 16. I have. In the present embodiment, since the preload is applied to the upper ball bearing 16 by the preload spring 30, the support in the radial direction is performed more firmly, and the rotation of the rotary shaft 14 is further stabilized.

The description of the specific embodiment has been completed.
Aspects of the present invention are not limited to this embodiment.
For example, in the above embodiment, a pair of upper and lower deep groove ball bearings was used as the rolling bearing, but other types of rolling bearings such as angular ball bearings and tapered roller bearings may be used, and the number thereof is also limited to two. Not something. Further, in the above embodiment, a magnetic bearing using an attractive force between a permanent magnet and a magnetic material is employed as the magnetic urging means. However, a magnetic bearing using an attractive force or a repulsive force between the permanent magnets may be employed. A control type that regulates the position of the rotating shaft in the radial direction and the thrust direction by controlling the power supply to the rotating shaft may be adopted.

[0020]

According to the present invention, there is provided a rotary shaft disposed substantially perpendicular to the apparatus housing, a flywheel integrated with the rotary shaft, and a converter for converting between electric energy and kinetic energy. A flywheel energy storage device that stores externally supplied electric energy as rotational energy of the flywheel. A rolling bearing provided for rotatable support; and a magnetic biasing means for biasing the rotating shaft or the flywheel upward to bear the weight of the rotating shaft and the flywheel and a preload of the rolling bearing. And vibration damping means interposed between the device housing and the rolling bearing, so that the rotating shaft and The rye wheel is supported in a state where it is pulled up and down by the biasing force of the magnetic biasing means and the axial fixing force based on the preload of the lower rolling bearing, so that it stably rolls not only at rest but also during rotation. Supported by bearings. Also, even if excessive vibration or yaw moment acts on the device housing, it becomes difficult for these to be transmitted to the rolling bearing or the rotating shaft by the action of the vibration damping means,
The rolling bearing is not damaged due to the destruction of the lubricating oil film or the like, and the desired performance can be maintained for a long time even when the rolling bearing is mounted on a self-propelled machine such as an electric vehicle.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a first embodiment of the present invention.

FIG. 2 is a longitudinal sectional view showing a second embodiment of the present invention.

FIG. 3 is a longitudinal sectional view showing an example of a conventional device.

[Explanation of symbols]

 1 magnetic bearing 2 flywheel 8 generator motor 9 equipment housing 14 rotating shaft 16 upper ball bearing 17 lower ball bearing 19,20 damping ring

Claims (1)

[Claims] 1. A rotary shaft disposed substantially vertically to an apparatus housing, a flywheel integrated with the rotary shaft, and energy conversion means for converting between electric energy and kinetic energy. A flywheel energy storage device for storing electric energy supplied from the outside as rotational energy of the flywheel, wherein at least a pair of upper and lower parts are provided with respect to the rotational shaft, and the rotatable shaft is provided for rotatable support. Rolling bearing, magnetic biasing means for biasing the rotating shaft or the flywheel upward to bear the weight of the rotating shaft and the flywheel and the preload of the rolling bearing, and the device housing. A vibration damping means interposed between the rolling bearing and the flywheel. Storage device.