JP4748890B2 - Flywheel battery - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a flywheel battery.
[0002]
[Prior art]
A flywheel battery (flywheel type) that fastens a flywheel having a rotor around the circumference to a shaft divided into two via a fastening member, and connects the shaft to a generator motor to store electric energy as rotational energy of the flywheel. As an example of the power storage device, a technique described in JP-A-52-65804 can be given. In this prior art, the flywheel is formed of a magnetic material into a disc shape.
[0003]
Moreover, as an example in which the flywheel is configured by a boss, a rim, and a plurality of spokes that connect the boss and the rim at a predetermined interval, a technique described in JP-A-2000-287399 can be cited.
[0004]
[Problems to be solved by the invention]
In this kind of flywheel battery, when the flywheel rotates at a high speed, the bending resonance frequency (natural frequency) of the flywheel itself has a high frequency and a low frequency as shown in FIG. It has the property of branching into two.
The same applies to the nth-order bending resonance wave.
[0005]
The degree of branching of the bending resonance frequency due to the gyro effect is determined by the ratio Ip / Id between the moment of inertia Ip around the rotation axis and the moment of inertia Id around the center of gravity axis perpendicular to the rotation axis. The greater the ratio Ip / Id, the greater the degree of resonance frequency branching with increasing rotation. In a rotating body having a large moment of inertia around the rotation axis such as a flywheel battery, the moment ratio of Ip / Id becomes large, and the influence of the gyro effect becomes remarkable.
[0006]
That is, as shown in FIG. 4, since the rotation speed corresponding to the intersections a, b, c, and d of the carrier line (rotational angular velocity) ω and each resonance frequency becomes a so-called dangerous speed, the maximum rotation speed of the flywheel Must be set in a range that does not exceed the minimum critical speed Na.
[0007]
Therefore, in order to increase the maximum usable rotational speed of the flywheel and expand the usable range, it is effective to increase the rigidity as the rotating body and shift the critical speed Na to the high rotation side.
[0008]
It is also effective to reduce the degree of branching of the resonance frequency by reducing the moment ratio of Ip / Id. If the moment ratio of Ip / Id can be reduced, for example, as shown by an imaginary line in FIG. 4, the degree of branching of the resonance frequency can be reduced, and the critical speed Nac is increased with the intersection point with the transport line ω as ac. It can be shifted to the rotation side.
[0009]
An object of the present invention is to eliminate the above-described problems, and to increase the rigidity as a rotating body to shift the dangerous speed to the high rotation side and to adjust the moment ratio, and thus to increase the maximum rotation speed of the flywheel. It is an object of the present invention to provide a flywheel battery that can be lifted to expand the usable range.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, in claim 1, a flywheel having a rotor on the circumference is fastened to a shaft divided into two via a fastening member, and the shaft is connected to a generator motor. In a flywheel battery that stores electrical energy as rotational energy of the flywheel, the shaft is configured to gradually increase in diameter from the tip side toward the flywheel, and the flywheel includes a boss and a rim. is attached to the rotor circumferentially of said integrally formed rim and a plurality of spokes connecting the boss and the rim at a predetermined interval, is offset from the connecting position of the spokes of the front Symbol boss to bored an insertion hole at a position to secure the insertion hole the fastening member inserted through allowed by the two divided shafts into and between the flywheel Configuration was.
[0011]
A flywheel having a rotor on the circumference is fastened to a shaft divided into two via a fastening member , and the shaft is configured to gradually increase in diameter from the tip side toward the flywheel. The diameter can be increased, and the rigidity of the rotating body can be increased. Thereby, the critical speed can be shifted to the high rotation side, and the usable range can be expanded by increasing the maximum rotation speed of the flywheel.
[0012]
Further, by making the shaft into a divided structure, the moment ratio of Ip / Id can be adjusted by the diameter and length of the shaft, and the bending resonance frequency can also be adjusted. Can be improved.
[0013]
Furthermore, the flywheel, the boss and the rim and with them integrally formed from a plurality of spokes that connect with a predetermined gap attaching the rotor to the circumference of the rim, the connection position of the ball scan spoke Since the insertion hole is drilled at the position offset from the shaft and the fastening member is inserted through the insertion hole so as to fix the divided shaft and the flywheel, the centrifugal force acting on the flywheel itself is rotated. The influence of deformation of each part of the flywheel can be reduced, the shearing force acting on the fastening means can be reduced, and the sliding between the shaft and the boss at the fastening means placement position can be reduced, so that the fastening means can be loosened. It can be avoided. Thus, the strength and reliability of the fastening means can be ensured, and therefore the rigidity of the rotating body can be further increased.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a flywheel battery according to an embodiment of the present invention will be described with reference to the accompanying drawings.
[0015]
FIG. 1 is a schematic view showing the entire flywheel battery including a generator motor.
[0016]
In FIG. 1, reference numeral 10 indicates the generator motor, and the generator motor 10 includes a housing 12. Inside the housing 12, a shaft 14 and a flywheel 20 that is fixed (fastened) through four bolts (fastening means) 16 through the bolt insertion holes 16 a are fastened and accommodated. Incidentally, the generator motor 10 is configured as a so-called flywheel battery as described in Japanese Patent Application Laid-Open No. 52-0665804 using the rotation of the flywheel 20 as stored energy.
[0017]
The shaft 14 is made of an iron material, and is made up of shaft half portions 14a and 14b as shown. The shaft halves 14 a and 14 b are both configured to have a large diameter from the tip side toward the flywheel 20.
[0018]
FIG. 2 is a schematic view showing the upper surface of the flywheel 20 including the fastening state with the shaft.
[0019]
As apparent from FIG. 2, the flywheel 20 has a wheel shape when viewed from above, and includes a boss 20a at the center, and is fixed (fastened) to the shaft halves 14a and 14b with bolts 16 on both sides of the boss (hub) 20a. Thus, the flywheel 20 is configured to be rotatable via the shaft 14.
[0020]
Between the boss 20a of the flywheel 20 and the annular rim 20b on the circumferential side, a plurality of (four) spokes extending from the boss 20a toward the rim 20b with a predetermined interval (90 degrees) ( Arm) 20c is integrally connected. The boss 20a, the rim 20b and the spoke 20c are made of an aluminum material. The rim 20b is formed to be relatively thin, and a rotor 20d made of a carbon fiber reinforced resin material is press-fitted and attached to the further circumferential side.
[0021]
As shown in the figure, the rotor 20d has a donut shape in a top view, and is composed of a plurality of pieces, for example, five pieces, each formed by laminating carbon fiber reinforced resins. Each piece is sequentially press-fitted into the outer periphery of the rim 20b.
[0022]
Thus, by manufacturing the rotor 20d from carbon fiber reinforced resin, it is possible to make the rotor 20d have high rotational strength while being lightweight. That is, energy E is
E = 1/2 (Ip × ω ² ) [J]
However, by increasing the rotational strength, the rotational angular velocity ω can be increased, in other words, it can be rotated at high speed (this rotation is high speed and reaches several tens of thousands rpm). As a result, a flywheel battery having a high energy density can be realized.
[0023]
A permanent magnet 22 is disposed on the outer periphery of the half portion 14b of the shaft 14, and the permanent magnet 22 is wound around the shaft 14 with a filament winding layer 24 to constitute a rotor (rotor) 26 of a generator motor. On the other hand, a stator (stator winding) 30 is fixed to the housing 12 with a predetermined gap (gap) from the rotor 26.
The rotor 26 and the stator 30 constitute a generator / motor.
[0024]
The shaft 14 (and the flywheel 20 fastened to the shaft 14) is rotatably accommodated in the housing 12 via a bearing 32. The bearing 32 is shown as a ball bearing for simplification of illustration, but actually comprises a magnetic bearing and supports the shaft 14 in a non-contact manner. Further, the interior 34 of the housing 12 is connected to a decompression device (not shown) and is configured to be held in a vacuum so as to reduce the air resistance when the flywheel 20 rotates.
[0025]
In the generator motor 10, the stator 30 is energized through an energization circuit (not shown) during charging, and the stator 30 and the rotor 26 operate as an electric motor to rotate the flywheel 20. At the time of discharging, the stator 30 and rotor 26 serve as a generator. Operates and converts the rotation of the flywheel 20 into electrical energy. The electric power thus generated is taken out through a circuit (not shown) and used for a desired application.
[0026]
What is characteristic in the illustrated configuration is that the flywheel 20 is composed of four spokes 20c that connect the boss 20a, the rim 20b, the boss 20a, and the rim 20b at a predetermined interval, and the circumference of the rim 20b. The rotor 20d is attached to the shaft 14 and the shaft 14 is divided into two half shaft portions 14a and 14b. The flywheel 20 is fastened to the two divided shafts 14 (shaft half portions 14a and 14b) via bolts (fastening members) 16. It is that.
[0027]
That is, since the shaft 14 is divided into two parts without being pierced by the boss 20a and the shaft 14 is press-fitted, the diameter of the shaft 14 can be increased and the rigidity as a rotating body can be increased. Can be raised. Thereby, the critical speed can be shifted to the high rotation side, and the usable range can be expanded by increasing the maximum number of rotations of the flywheel 20.
[0028]
Furthermore, by making the shaft 14 into a divided structure, the bending resonance frequency and the moment ratio can be adjusted by the diameter and length of the shaft 14, and the degree of freedom of setting them can be improved. Therefore, the adjustment of the moment ratio required by the magnetic bearing 32 is facilitated. Further, it is not necessary to secure a press-fitting allowance between the boss 20a and the shaft 14.
[0029]
However, as mentioned above, the flywheel 20 is generated during high rotation, the respective parts by the centrifugal force of its own deformation, specifically, modified as each section is inflated radially outward. Therefore, it is necessary to determine the arrangement position of the bolt 16 in consideration of this point.
[0030]
This will be described with reference to FIG. 3. As shown in FIG. 3 (a), the bolt 16 is disposed at the connection position of the spoke 20c of the boss 20a, that is, at the root of the spoke 20c. The position of the boss 20a offset from the connection position of the spoke 20c, as shown in FIG. 5B, that is, when it is placed between the spokes 20c, and the root of the spoke 20c and the spoke 20c as shown in FIG. The case where it arrange | positions together between is considered.
[0031]
In this case, as shown in FIG. 3 (a) (c), if you drilled bolt insertion hole 16a at the base of the spokes 20c placing bolt 1 6 therein, is pulled by the centrifugal force acting on the spoke 20c Since the bolt insertion hole 16a moves in the radial direction (centrifugal force acting direction), a large shearing force is generated in the bolt 16. In addition, the movement causes a sliding between the shaft 14 and the bolt 16 and causes the bolt 16 to loosen.
[0032]
Therefore, in this embodiment, as shown in FIG. 3B, the bolt 16 is disposed at a position offset from the connection position of the spoke 20c of the boss 20a, that is, between the spokes 20c. Thereby, the influence of deformation of each part of the flywheel 20 due to the centrifugal force acting on the flywheel 20 itself during rotation can be reduced.
[0033]
That is, the displacement amount of the bolt insertion hole 16a due to the centrifugal force acting on the spoke 20c can be reduced, and the shear force acting on the bolt 16 and the bolt 14 in the bolt insertion hole 16a causing loosening of the bolt 16 and the boss 20 can be reduced. Since the sliding of a can also be reduced, loosening of the bolt 16 can be avoided. Thus, since the strength and reliability of the fastening means 16 can be ensured, the rigidity of the rotating body can be further increased.
[0034]
As shown in FIG. 2, the bolt 16 is arranged at the exact center position between the adjacent spokes 20c, but it is sufficient to arrange the bolt 16 at a position offset from the connection position of the left spoke 20c. The center position may not be shifted to the left and right.
[0035]
Needless to say, the example of the fastening means is not limited to the bolt 16, and the number of the bolts 16 is not limited to the number shown in the drawing.
[0036]
In this embodiment, as described above, the flywheel 20 having the rotor 20d on the circumference is fastened to the shaft 14 (shaft halves 14a and 14b) divided into two via fastening members (bolts 16), and the shaft In a flywheel battery in which electrical energy is stored as rotational energy of the flywheel 20 by connecting 14 to a generator motor, the shaft 14 is configured to gradually increase in diameter from the tip side toward the flywheel 20. The flywheel is integrally configured with a boss 20a, a rim 20b, and a plurality of spokes 20c that connect the boss and the rim at a predetermined interval, and the rotor 20 is attached to the circumference of the rim. together, bored an insertion hole 16a at a position is offset from the connecting position of the spokes of the front Symbol boss, the insertion hole 1 and configured to secure the bisected shaft 14 and said flywheel 20 inserted through so the fastening member 16 to a.
[0037]
More specifically, in the flywheel battery, the flywheel 20 is configured by four spokes 20c that connect the boss 20a, the rim 20b, the boss 20a, and the rim 20b at a predetermined interval, and the rim 20b. The rotor 20d is attached to the circumference, the shaft 14 is divided into two half shafts 14a and 14b, and the flywheel 20 is divided into two divided shafts 14 (shaft half portions 14a and 14b) via fastening members (bolts) 16. The shaft 14 is connected to a generator motor to accumulate electrical energy as rotational energy of the flywheel 20, and the fastening member is offset from the connection position of the spoke 20c of the boss 20a. Configured to place.
[0038]
【The invention's effect】
In claim 1, the flywheel having a rotor around the circumference is fastened to a shaft divided into two via a fastening member, and the diameter of the shaft gradually increases from the tip side toward the flywheel. With this configuration, it is possible to increase the diameter of the shaft and increase the rigidity of the rotating body. Thereby, the critical speed can be shifted to the high rotation side, and the usable range can be expanded by increasing the maximum rotation speed of the flywheel.
[0039]
Further, by making the shaft into a divided structure, the moment ratio of Ip / Id can be adjusted by the diameter and length of the shaft, and the bending resonance frequency can also be adjusted. Can be improved.
[0040]
Furthermore, the flywheel, the boss and the rim and with them integrally formed from a plurality of spokes that connect with a predetermined gap attaching the rotor to the circumference of the rim, the connection position of the ball scan spoke Since the insertion hole is drilled at the position offset from the shaft and the fastening member is inserted through the insertion hole so as to fix the divided shaft and the flywheel, the centrifugal force acting on the flywheel itself is rotated. The influence of deformation of each part of the flywheel can be reduced, the shearing force acting on the fastening means can be reduced, and the sliding between the shaft and the boss at the fastening means placement position can be reduced, so that the fastening means can be loosened. It can be avoided. Thus, the strength and reliability of the fastening means can be ensured, and therefore the rigidity of the rotating body can be further increased.
[Brief description of the drawings]
FIG. 1 is a schematic view showing a flywheel battery according to an embodiment of the present invention as a whole including a generator motor.
FIG. 2 is a schematic view showing the top surface of the flywheel shown in FIG. 1 including a fastening state with a shaft.
FIG. 3 is an explanatory view showing an example of an arrangement position of a bolt for fastening a flywheel and a shaft shown in FIG. 1. FIG. 4 is a bending resonance frequency (natural vibration) of the flywheel due to a gyro effect at the time of rotation in the flywheel battery. It is explanatory graph which shows the influence on number).
[Explanation of symbols]
10 generator motor 14 shaft 16 bolt (fastening means)
16a Bolt insertion hole 20 Flywheel 20a (flywheel) boss 20b (flywheel) rim 20c (flywheel) spoke 20d (flywheel) rotor 22 Permanent magnet 24 Filament winding layer 26 (generator motor) rotor 30 Stator (of generator motor)

Claims (1)

In a flywheel battery that fastens a flywheel having a rotor on the circumference to a shaft divided into two via a fastening member, and connects the shaft to a generator motor to store electric energy as rotational energy of the flywheel. The shaft is configured to gradually increase in diameter from the tip side toward the flywheel, and the flywheel includes a plurality of spokes that connect the boss, the rim, and the boss and the rim at a predetermined interval. inserted with and integrally formed mounting the rotor to the circumference of the rim, bored an insertion hole at a position is offset from the connecting position of the spokes of the front Symbol boss, the fastening member into the insertion hole from A flywheel battery characterized in that the shaft divided into two and the flywheel are fixed.

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