JPH08298745A - Flywheel device - Google Patents

Abstract

PURPOSE: To obtain a flywheel device which prevents the structure of a bearing from becoming complicated and the bearing from becoming large-sized, in which the force- fitting and fixing operation of a ring-shaped member is simplified and in which the accuracy of the position control in the radial direction of a rotating body is enhanced. CONSTITUTION: A flywheel device is provided with a vertical fixed axis 2 and with a vertical cylindrical rotating body 3 the upper end of which is opened, the lower end of which is closed and which is arranged around the fixed axis 2 in such a way that it can be moved and turned in the axial direction and the radial direction with reference to the fixed axis 2. A flywheel 4 is installed so as to be fixed around the opening end part of the rotating body 3. The flywheel 4 is formed in such a way that a ring-shaped reinforcement member 5 is force-fitted and fixed around an outward flange 3a at the opening end part of the rotating body 3. An axial magnetic bearing 6, a permanent magnet bearing 7 and a superconducting bearing 8 which support the rotating body 3 in a noncontact manner in the axial direction with reference to the fixed axis 2 and radial magnetic bearings 9, 10 which support the rotating body in a noncontact manner in the radial direction are installed. Any of the radial magnetic bearings 9, 10 is endowed with an electrically-driven driving function.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flywheel device used for an electric power storage device for converting surplus electric power into rotational kinetic energy of a flywheel and storing it.

[0002]

2. Description of the Related Art As a flywheel device of this type, conventionally, it is arranged so as to be movable and rotatable in the axial direction and the radial direction with respect to a fixed portion, and rotates about a vertical axis. A solid rotary shaft; a flywheel fixedly provided around one end of the rotary shaft; a non-contact bearing for supporting the rotary shaft in a non-contact manner with respect to the fixed part in the axial direction and the radial direction; It is known that a flywheel is formed by press-fitting and fixing an annular member around one end of a rotary shaft.

However, in this flywheel device, in order to improve the power storage efficiency, for example, a diameter of 1
When a large flywheel of 000 mm or more is used, it is necessary to increase the outer diameter of the rotary shaft so as not to reduce the natural frequency, and the weight of the rotary shaft becomes large. As a result, in order to stably and non-contactly support the rotary shaft in the axial direction with respect to the fixed portion, it is necessary to increase the rigidity and load capacity of the bearing that is non-contactly and axially supported. Therefore, there is a problem that the structure of this bearing becomes complicated and increases in size. Further, in this flywheel device, when the rotating shaft is rotated at a high speed, the annular member expands due to the centrifugal force, so that a gap is generated between the annular member and the rotating shaft, and the flywheel shakes or rattles. There is a problem that occurs. To prevent this,
It is necessary to increase the tightening margin, but in that case, there is a problem that the work of press-fitting and fixing the annular member is extremely difficult because the rotating shaft is solid.

In order to solve such a problem, a vertical fixed shaft and both ends thereof are opened and arranged around the fixed shaft so as to be movable and rotated in the axial and radial directions with respect to the fixed shaft. A vertical cylindrical rotating body, a flywheel fixedly provided around one end of the rotating body, a non-contact bearing that supports the rotating body in a non-contact axial direction with respect to a fixed shaft, and also in the radial direction. A flywheel including a control type magnetic bearing for non-contact support and a drive source for rotationally driving a rotating body, wherein the flywheel is formed by press-fitting and fixing an annular member around one end of the rotating body. The device is considered.

In this flywheel device, since the rotating body is cylindrical with both ends open, the rotating body is easily bent when the annular member is press-fitted and fixed, and the operation can be performed easily. When rotated at a high speed, the rotating body itself expands due to centrifugal force, and there is a problem in that the accuracy of position control in the radial direction of the rotating body deteriorates.

An object of the present invention is to provide a flywheel device that solves the above problems.

[0007]

A flywheel device according to the present invention has a vertical fixed shaft, one end of which is open and the other end of which is closed, and the flywheel device can move and rotate in the axial and radial directions with respect to the fixed shaft. The vertical cylindrical rotating body arranged around the fixed shaft, the flywheel fixedly arranged around the open end of the rotating body, and the rotating body in the axial and radial directions with respect to the fixed shaft. A non-contact bearing for non-contact support and a drive source for rotationally driving the rotating body are provided, and the flywheel is
It is formed by press-fitting and fixing an annular member around the open end of the rotating body.

[0008]

Since the rotating body is a vertical cylinder having one end open and the other end closed, the weight of the rotating body is smaller than that of the solid rotating shaft of the conventional device. Therefore, the rigidity and load capacity of the bearing that supports the rotary shaft in a non-contact manner with respect to the fixed portion in the axial direction can be made smaller than the bearing of the conventional device.

The rotary body is a vertical cylinder having one end open and the other end closed, and a flywheel is formed by press-fitting and fixing an annular member around the open end of the rotary body. Therefore, it becomes easy to bend the rotary member during the press-fitting and fixing work of the annular member, and as a result, the press-fitting and fixing work can be easily performed.

Further, since the rotating body has a vertical cylindrical shape with one end open and the other end closed, the rotating body expands due to centrifugal force even when the rotating body is rotated at a high speed by the drive source. Is prevented.

[0011]

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

FIG. 1 schematically shows the overall structure of a power storage device to which a flywheel device is applied. This power storage device includes a vacuum chamber (1) and a top wall (1a) of the vacuum chamber (1). A vertical fixed shaft (2), which is fixed to the fixed shaft (2), and an upper end that is open and a lower end that is closed, and a fixed shaft (2) that is movable and rotatable in the axial and radial directions with respect to the fixed shaft (2). It has a vertical cylindrical rotating body (3) arranged around 2) and a flywheel (4) fixedly provided around the open end of the rotating body (3).

The vertical fixed shaft (2) is made of a non-magnetic material such as aluminum alloy, non-magnetic stainless steel, copper alloy or the like, and an outward flange (2a) is integrally formed on the upper end thereof. . The rotating body (3) is made of aluminum alloy,
It is formed of a non-magnetic material such as non-magnetic stainless steel or copper alloy. Flywheel (4) is a rotating body (3)
Outer flange (3a) integrally formed at the upper end of the ring, and CFRP (composite fiber reinforced plastic) annular reinforcing member (annular member) press-fitted and fixed to the outer periphery of the outward flange (3a)
It consists of (5).

A control type axial magnetic bearing (6) is provided between the lower surface of the outward flange (2a) of the vertical fixed shaft (2) and the upper surface of the outward flange (3a) of the rotating body (3). Vertical fixed axis
A permanent magnet bearing (7) is provided between the lower surface of (2) and the upper surface of the lower end closing wall (3b) of the rotating body (3) to urge the rotating body (3) upward by a magnetic attraction force. Lower end closing wall (3
A superconducting bearing (8) is provided between the lower surface of b) and the upper surface of the bottom wall (1b) of the vacuum chamber (1), and the superconducting bearing (8) biases the rotating body (3) upward by magnetic repulsion force. ) Peripheral surface and rotating body (3)
Between the inner peripheral surface of the peripheral wall of
Two sets of upper and lower control type radial magnetic bearings (9) (10) for controlling the position in one radial direction are provided.

The control type axial magnetic bearing (6) has a vertical fixed shaft (2) on the lower surface of the outward facing flange (2a) of the vertical fixed shaft (2).
An annular electromagnet section (11) concentrically provided for sucking the rotating body (3) from the upper side in the axial direction (Z-axis direction) to control the position of the rotating body (3) in the same direction; Department (1
An annular ferromagnetic body (12) provided on the upper surface of the outward flange (3a) of the rotating body (3) so as to face the vertical direction with respect to 1).
It has and. Outer flange (2a) of vertical fixed axis (2)
An annular groove (13) is formed concentrically with the fixed shaft (2) on the lower surface of the annular groove (13), and the annular electromagnet (14), and the inner peripheral surface of the electromagnet (14), An electromagnet portion (11) is configured by fitting and fixing a yoke member (15) that covers the outer peripheral portion of the upper surface, the outer peripheral surface, and the lower surface.
Annular downward protrusions (15a) are integrally formed on both side edges of (5). On the upper surface of the ferromagnetic body (12), make sure that the two downward protrusions (15a) of the yoke member (15) face each other.
Two annular upper protrusions (12a) are integrally formed. Although not shown, the axial magnetic bearing (6) is equipped with a displacement sensor for detecting the displacement of the rotating body (3) in the Z-axis direction, and the electromagnet (14) and the displacement sensor are not shown in the figure. It is connected to the bearing controller. Then, the magnetic bearing controller controls the electromagnet (1
The current value of 4), that is, the attraction force is controlled, and as a result, the rotating body
The position of (3) in the axial direction is controlled. Since the axial magnetic bearing (6) and its control device are publicly known, detailed description will be omitted.

The permanent magnet bearing (7) is provided on the fixed permanent magnet portion (16) provided on the lower surface of the vertical fixed shaft (2) and on the upper surface of the lower end closing wall (3b) of the rotating body (3). It consists of a rotating permanent magnet part (17). A cylindrical hole (18) is formed in the center of the lower surface of the fixed shaft (2), and an annular groove (19) is formed around it.
It is formed concentrically with the axis of (2), and the cylindrical fixed permanent magnet (20) is fitted and fixed in the cylindrical hole (18),
The fixed permanent magnet portion (16) is configured by fitting and fixing the fixed annular magnet (21) in the annular groove (19). Both fixed permanent magnets (20) and (21) have magnets of opposite polarities at their upper and lower ends, respectively, and the vertical fixed ends of the cylindrical fixed permanent magnet (20) and the annular fixed permanent magnet (21). The part is magnetized with the opposite polarity. For example, the upper end of the columnar fixed permanent magnet (20) has an N pole and the lower end has an S pole, and the upper end of the annular fixed permanent magnet (21) has an S pole.
The lower end has an N-pole magnetism. A cylindrical hole (22) is formed in the center of the upper surface of the lower end closing wall (3b) of the rotating body (3), and an annular groove (23) is concentric with the axial center of the rotating body (3) around it. The cylindrical rotary permanent magnet (24) is fitted and fixed in the cylindrical hole (22), and the annular groove (23) is formed.
The rotary permanent magnet portion (17) is configured by fitting and fixing the annular rotary permanent magnet (25) therein. The rotating permanent magnets (24) (25) are arranged so as to face the fixed permanent magnets (20) (21). Both rotating permanent magnets (24) (25)
Both the upper and lower ends have magnetism of opposite polarities, and the columnar fixed permanent magnet (24) and the annular rotating permanent magnet.
Both ends of (25) in the vertical direction are magnetized with opposite polarities. In addition, each rotating permanent magnet (24) (25) and each fixed permanent magnet (2
The opposite ends of (0) and (21) are magnetized with opposite polarities. For example, the upper end of the cylindrical rotating permanent magnet (24) is N
The pole and the lower end are magnetized as the S-pole, and the upper end of the annular rotating permanent magnet (25) is magnetized as the S-pole and the lower end is magnetized as the N-pole.

The superconducting bearing (8) has an annular permanent magnet portion (26) provided on the lower surface of the lower end closing wall (3b) of the rotating body (3) and a vertical direction with respect to the permanent magnet portion (26). It is composed of an annular superconductor portion (27) provided on the upper surface of the bottom wall (1b) of the vacuum chamber (1) so as to face each other with a space. A plurality of annular concave grooves (28) are formed on the lower surface of the lower end closing wall (3b) of the rotating body (3) concentrically with the rotation axis, and an annular permanent magnet (29) is formed in each annular concave groove (28). The permanent magnet portion (26) is configured by fitting and fixing the. The upper and lower end portions of each permanent magnet (29) are magnetized with opposite polarities, and the same vertical end portions of adjacent permanent magnets (29) are magnetized with opposite polarities. For example, the upper end of the inner permanent magnet (29) is magnetized with the S pole and the lower end is magnetized with the N pole, and the upper end of the outer permanent magnet (29) is magnetized with the N pole and the lower end is magnetized with the S pole. It is tinged. The superconductor part (27) includes an annular cooling case (31) fixed on the upper surface of the bottom wall (1b) of the vacuum chamber (1) via a heat insulating material (30). Cooling case
(31) is made of a non-magnetic material such as aluminum alloy, non-magnetic stainless steel or copper alloy. An annular superconductor (32) is fixedly arranged in a space inside the cooling case (31).
The cooling case (31) has a cooling fluid supply pipe (33) and an exhaust pipe (3).
4) is connected to a cooling device (not shown) through which a cooling fluid such as liquid nitrogen is supplied via the supply pipe (33), the space inside the cooling case (31) and the discharge pipe (34). The superconductor (32) is cooled by this. The superconductor (32) is a type 2 superconductor, and is a yttrium-based high temperature superconductor such as YB.
Inside the bulk made of a ₂ Cu ₃ O _7-X , a normal conductor (Y
₂ Ba ₁ Cu ₁ ) is uniformly mixed. Then, the superconductor (32) is cooled to a temperature below the critical temperature (hereinafter, this cooling is referred to as zero magnetic field cooling) by arranging the superconductor (32) at a separated position where the magnetic field of the permanent magnet (29) is not received, and It exhibits magnetism.

Although not shown in detail in the radial magnetic bearings (9) and (10), the rotor (3) is attracted from both sides in two radial directions (X-axis and Y-axis directions) orthogonal to each other. It is equipped with an electromagnet for controlling the position of the rotating body (3) in the same direction, and a displacement sensor for detecting the displacement of the rotating body (3) in the X-axis and Y-axis directions. It is connected to the control device. Then, the magnetic bearing control device controls the current value of the electromagnet, that is, the attractive force, based on the output of the displacement sensor, and as a result, the position of the rotating body (3) in the radial direction is controlled. Since the radial magnetic bearings (9) and (10) and their control devices are publicly known, detailed description is omitted. At least one set of the radial magnetic bearings (9) (10) has an electric drive function for rotationally driving the rotating body (3) in addition to the position control function of the rotating body (3). A control type radial magnetic bearing having an electric drive function is known as a levitating rotary motor or a bearingless motor, and therefore detailed description thereof will be omitted.

In the above power storage device, the initial positioning device (35) for setting the relative position of the fixed shaft (2) of the vacuum chamber (1) and the rotating body (3) before operation is as follows. Is provided.

Below the rotating body (3), an elevating member (36) which can be moved up and down by a known appropriate means is installed in the vacuum chamber (1).
Is arranged so as to penetrate the bottom wall (1b) of the. A concave spherical recess (37) is formed on the upper surface of the elevating member (36). Further, a hemispherical body (38) fitted in the recess (37) is provided in a downwardly projecting and fixed manner at the center of the lower surface of the lower end closing wall (3b) of the rotating body (3). Then, when the elevating member (36) is raised, the rotating body (3) in the stopped state is lifted while the hemispherical body (38) is fitted in the recess (37), and the rotating body (3) is moved in the axial direction. The initial positioning of is performed. It should be noted that the lifting member (36) has a hemispherical body (38) with a recess (3
It is in the lowered position where it does not contact the inner surface of 7).

A dynamic pressure bearing is formed by the recess (37) on the upper surface of the lifting member (36) of the initial positioning device (35) and the hemispherical body (38). It is a touchdown bearing (39) that supports the lower end in a non-contact manner. Further, a touchdown bearing (40), which is a rolling bearing, is provided above the vertical fixed shaft (2) to support the upper portion of the rotating body (3) in an emergency.

When starting the rotation of the rotating body (3), first, the vacuum chamber (1) is evacuated, and the rotating body (3) in the stopped state is moved to a predetermined position by the initial positioning device (35). Lift and perform initial positioning of the rotating body (3) in the axial direction. At this time, the axial distance between the downward protrusion (15a) of the yoke member (15) of the electromagnet portion (11) of the axial magnetic bearing (6) and the upward protrusion (12a) of the ferromagnetic body (12) is The distance between the lower protrusions (15a) of the yoke members (15) in the radial direction is made smaller. Further, the superconductor (32) of the superconducting bearing (8) is positioned so as not to receive the magnetic field of the permanent magnet (29) and its magnetic flux does not enter. Then, only the position control function of the upper and lower radial magnetic bearings (9) (10) is operated to perform the initial radial positioning of the rotating body (3). At this time, the rotating permanent magnets (24) (25) of the permanent magnet bearing (7) are fixed permanent magnets (20) (2
An upward suction force is received from 1), which supports a part of the weight of the rotating body (3). And axial magnetic bearing
Energize the electromagnet (14) of (6). Then, a magnetic circuit as shown by a broken line in FIG. 1 is formed between the electromagnet part (11) of the axial magnetic bearing (6) and the ferromagnetic body (12), and the ferromagnetic body (12) attracts upward attracting force. Therefore, a part of the weight of the rotating body (3) is also supported by this. The sum of the upward attracting force received by the rotating permanent magnets (24) and (25) and the upward attracting force received by the ferromagnetic body (12) is set to be substantially equal to the weight of the rotating body (3). Next, a cooling fluid is circulated in the cooling case (31) of the superconducting bearing (8) by the cooling device to cool the superconductor (32) to a temperature below the critical temperature to bring it into a superconducting state, and maintain this state. That is, a diamagnetic state appears in the superconductor (32). Then, when the elevating member (36) is lowered, the rotating body (3) is biased upward by the magnetic repulsive force generated between the permanent magnet (29) and the superconductor (32). Therefore,
The rotating body (3) is supported in the axial direction and the radial direction in an extremely stable state. In this way, the axial magnetic bearing (6), permanent magnet bearing (7), superconducting bearing (8) and radial magnetic bearing (9) (10)
When (3) is supported, the lifting member (36) is further lowered to eliminate the support of the rotating body (3) by the initial positioning device (35). As a result, the rotating body (3) is
(6), the permanent magnet bearing (7), the superconducting bearing (8), and the radial magnetic bearing (9) (10) are non-contact supported. When the rotating body (3) is supported in a non-contact manner, the electric drive function of one of the radial magnetic bearings (9) (10) is activated to rotate the rotating body (3). Then, while the rotating body (3) is rotating, electric energy is converted into rotational kinetic energy and stored in the flywheel (4). While the rotating body (3) is rotating, the position control function of the axial magnetic bearing (6) and radial magnetic bearings (9) (10) allows the rotating body to rotate.
(3) It is possible to prevent axial and radial runout.

When a power failure occurs while the rotating body (3) is rotating, the electric drive function of any of the radial magnetic bearings (9) (10) is stopped, but the flywheel (4) causes
The rotating body (3) is continuously decelerated although it is slightly decelerated. As a result, the radial magnetic bearings (9) (10) with electric drive function as generators, and flywheel
The rotational kinetic energy stored in (4) is taken out as electric energy and stored in a storage battery (not shown). The electric power stored in the storage battery is sent to an external power consumer goods and superconducting bearing (8) cooling device (not shown), and the power consumer goods and the superconducting bearing (8) continue to operate. A part of the electric power stored in the storage battery is sent to the magnetic bearing control device of the axial magnetic bearings (6) and radial magnetic bearings (9) (10), which causes these magnetic bearings (6) (9) (10). The position control function of is activated. Then, until the rotational kinetic energy stored in the flywheel (4) decreases and the rotating body (3) stops, the rotating body (3) keeps the axial magnetic bearing (6),
Non-contact supported by permanent magnet bearings (7), superconducting bearings (8) and radial magnetic bearings (9) (10). Moreover, the position control function of the axial magnetic bearing (6) and the radial magnetic bearings (9) (10) prevents the rotor (3) from swinging in the axial direction and the radial direction.

In the above embodiment, the axial magnetic bearing (6) and the radial magnetic bearings (9) and (10) are magnetic bearings each having a displacement sensor. Instead of this, a known sensorless magnetic bearing is used. It can also be used. In this case, it is possible to prevent a decrease in safety due to a failure of the sensor circuit.

In the above embodiment, at least one set of radial magnetic bearings (9) (10) has an electric drive for rotating the rotating body (3) in addition to the position control function of the rotating body (3). Although it has a function, the radial magnetic bearings (9) and (10) are not limited to this, and may have only the position control function. In this case, the fixed shaft (2) and the rotating body (3)
A rotary drive source such as a high-frequency motor is provided between and.

In the above embodiment, the superconducting bearing is also used.
A type 2 superconductor is used as the superconductor (32) of (8),
The permanent magnet (29) is urged upward due to the magnetic repulsive force when it is cooled to zero magnetic field. However, even if a type 2 superconductor is used, it is generated from the permanent magnet (29). The magnetic flux to enter inside the superconductor (32) at a temperature above the critical temperature, and then cool (magnetic field cooling) the superconductor (32) to a temperature below the critical temperature and confine it by so-called pinning force. The permanent magnet (29) may be biased upward by the generated magnetic repulsive force. Further, as the superconductor of the superconducting bearing (8), a type 1 superconductor made of mercury, lead, or the like and exhibiting complete diamagnetism may be used instead of the type 2 superconductor. In this case, the permanent magnet is biased upward by the superconductor due to the magnetic repulsive force due to the Meissner effect of the superconductor.

[0027]

According to the flywheel device of the present invention, as described above, since the weight of the rotating body is smaller than that of the solid rotating shaft of the conventional device, the rotating body is axially attached to the fixed portion. The rigidity and load capacity of the bearing that is supported in a non-contact direction can be made smaller than that of the bearing of the conventional device. Therefore, it is possible to prevent the bearing structure from becoming complicated and the bearing from increasing in size.

The rotary body is a vertical cylinder having one end open and the other end closed, and the flywheel is formed by press-fitting and fixing an annular member around the open end of the rotary body. Therefore, it becomes easy to bend the rotary member during the press-fitting and fixing work of the annular member, and as a result, the press-fitting and fixing work can be easily performed.

Further, since the rotating body has a vertical cylindrical shape with one end open and the other end closed, the rotating body expands due to centrifugal force even when the rotating body is rotated at a high speed by the drive source. Is prevented. Therefore, the accuracy of the radial position control of the rotating body is improved.

[Brief description of drawings]

FIG. 1 is a schematic vertical sectional view of a power storage device to which a flywheel device according to an embodiment of the present invention is applied.

[Explanation of symbols]

 (2) Vertical fixed shaft (3) Vertical cylindrical rotor (3b) Bottom closed wall (4) Flywheel (5) Annular reinforcing member (annular member) (6) Axial magnetic bearing (7) Permanent magnet bearing (8) Superconducting bearing (9) Radial magnetic bearing (10) Radial magnetic bearing

Claims (1)

[Claims] 1. A vertical fixed shaft and a vertical cylinder which is open at one end and closed at the other end and is arranged around the fixed shaft so as to be movable and rotatable in the axial direction and the radial direction with respect to the fixed shaft. -Shaped rotating body, a flywheel fixedly provided around the opening end of the rotating body, a non-contact type bearing that supports the rotating body in a non-contact manner with respect to a fixed shaft in the axial direction and the radial direction, and the rotating body It has a drive source to rotate the
A flywheel device formed by press-fitting and fixing an annular member around the open end of a rotating body.