JPH08178011A - Flywheel device - Google Patents

Abstract

PURPOSE: To provide a flywheel device having a large load capacity in the axial direction and a small rotation loss. CONSTITUTION: This flywheel device is provided with a vertical rotary shaft 1, a flywheel 2 fixed to it, four-axis control type radial magnetic bearings 3, 4 supporting the rotary shaft 1 in the radial direction in no contact, multiple circular rotary permanent magnets 10 concentrically laminated on the lower end face 2a of the flywheel 2 and having magnetic poles at both ends in the axial direction, and multiple circular fixed permanent magnets 11 concentrically laminated on a housing 7 below the permanent magnets 10 and having magnetic poles at both ends in the axial direction. The magnetic poles at the same end of two adjacent rotary permanent magnets 10 have opposite polarities to each other, and the magnetic pole at the lower end of the rotary permanent magnets 10 and the magnetic pole at the upper end of the fixed permanent magnets 11 facing it have the same polarity.

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 Conventionally, as a flywheel device of this type, a rotary shaft that rotates about a vertical axis, a flywheel that is fixedly mounted on the rotary shaft, and two upper and lower sets that support the rotary shaft in a radial direction without contact. 4 axis control type radial magnetic bearing,
Further, there is known one provided with one set or a plurality of sets of superconducting bearings for supporting the rotary shaft in a radial direction and an axial direction in a non-contact manner. A superconducting bearing has, for example, a plurality of annular permanent magnets on the upward or downward end face of the flywheel, the magnetic flux distribution being symmetrical with respect to the rotation axis, and the magnetic flux distribution around the rotation axis being rotated. It is arranged concentrically so that it does not change, and in the fixed portion, the superconductor is a separated position where the magnetic flux of the permanent magnet enters a predetermined amount, and the position where the distribution of the invading magnetic flux does not change due to the rotation of the rotating body, It is arranged so as to face the permanent magnet in the direction of the axis of rotation. Then, the magnetic flux generated from the permanent magnet is allowed to enter the inside of the superconductor to be restrained, and as a result, the so-called pinning force supports the rotating body in a non-contact state in the radial direction and the axial direction with respect to the fixed portion. It is like this.

[0003]

In the above flywheel device, only the superconducting bearing supports the rotary shaft in the axial direction. Superconducting bearings, as mentioned above,
Although the rotating body can be supported in the radial and axial directions by the pinning force of the magnetic flux bound by the superconductor,
Especially, there is a limit to the supporting force (load capacity) in the axial direction (gravitational direction), and rotation loss becomes a problem.

The object of the present invention is to solve the above problems,
An object of the present invention is to provide a flywheel device having a large axial load capacity and a small rotation loss.

[0005]

A flywheel device according to the present invention comprises a rotary shaft which rotates about a vertical axis, a flywheel fixedly mounted on the rotary shaft, and a non-contact support for the rotary shaft in a radial direction. Upper and lower two sets of four-axis control type radial magnetic bearings, a plurality of disc-shaped non-magnetic rotary members fixed to the flywheel or the rotary shaft, concentrically laminated on the lower surface, and having magnetic poles at both axial ends. Ring-shaped rotary permanent magnets, and a plurality of ring-shaped fixed permanent magnets concentrically laminated on the fixed portion below the flywheel or the rotating member so as to face the rotary permanent magnets, and have magnetic poles at both axial ends. And the magnetic poles at the same end of the two rotary permanent magnets that are adjacent in the radial direction have opposite polarities, and are opposed to the magnetic pole at the lower end of the rotary permanent magnet. It is characterized in that the magnetic poles of the upper end of the fixed permanent magnets are made to have the same polarity.

For example, an annular composite fiber reinforced plastic reinforcing member is integrally fixed to the outer periphery of the flywheel or the rotating member.

[0007]

Since the magnetic pole at the lower end of the rotary permanent magnet on the flywheel side and the magnetic pole at the upper end of the fixed permanent magnet on the fixed portion side facing the flywheel side have the same polarity as each other, the magnetic repulsive force causes the rotary permanent magnet to move upward. Since the load is biased to support the weight of the rotating shaft, the load capacity in the axial direction increases. Further, since the rotating shaft is supported in the axial direction only by the magnetic repulsive force of the permanent magnet without using the superconducting bearing, the rotation loss is small, and an expensive superconductor or its cooling device is not required. Therefore, energy saving is achieved and the cost is reduced.

When the annular composite fiber reinforced plastic reinforcing member is integrally fixed to the outer periphery of the flywheel or the rotating member, the reinforcing member suppresses the centrifugal expansion of the flywheel or the rotating member to a small level, and the flywheel is rotated. Alternatively, centrifugal breakdown of the rotating member is prevented.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a flywheel device in a power storage device will be described below with reference to the drawings.

FIG. 1 schematically shows the overall structure of the flywheel device, and FIG. 2 shows a part of the flywheel device in detail.

The flywheel device has a vertical rotation axis (1).
, A flywheel (2) fixed to the rotating shaft (1), two sets of upper and lower 4-axis control radial magnetic bearings (3) (4) that support the rotating shaft (1) in the radial direction in a non-contact manner, the rotating shaft ( Permanent magnet bearing that supports 1) in the axial direction (vertical direction) without contact (5)
, And a generator motor (6), which are arranged in a vacuum chamber (8) surrounded by a housing (fixed part) (7) made of a plurality of members.

The flywheel (2) is made of a non-magnetic material such as an aluminum alloy and has a disk shape.
An annular reinforcing member (9) made of CFRP (composite fiber reinforced plastic) is integrally fixed to the outer periphery thereof. The flywheel (2) is concentrically fixed to the lower end of the rotating shaft (1), and the rotating shaft (1) moves slightly up and down (moves in the axial direction) in the center of the housing (7). It is arranged so that it can be moved in the radial direction.

The permanent magnet bearing (5) is composed of the lower end surface (2a) of the flywheel (2) and the upper surface of the bottom wall of the housing (7) facing the lower end surface (2a).
It is provided between (7a) and the details are shown in FIG.

The permanent magnet bearing (5) is a flywheel (2).
A plurality of annular rotating permanent magnets (10) concentrically arranged on the lower end surface (2a) of the
The bottom wall upper surface (7a) of (7) is provided with the same number of annular fixed permanent magnets (11) arranged concentrically.

On the lower end surface (2a) of the flywheel (2), a plurality of annular grooves (13) partitioned by a circular partition wall (12) are concentrically formed, and rotate in each groove (13). 1 permanent magnet (10)
They are fitted and fixed one by one. The outer peripheral part of the rotating permanent magnet (10) is a wall or partition wall on the outer peripheral side of the groove (13).
It is press-fitted into the inner peripheral part of (12). The inner peripheral part of the rotating permanent magnet (10) is loosely fitted to the outer peripheral part of the partition wall (12) or the inner wall of the groove (13), with little or no gap between them. Has been opened. The rotating permanent magnet (10) has magnetic poles at both ends in the axial direction,
The magnetic poles at the same end of two rotating permanent magnets (10) that are adjacent in the radial direction are arranged so as to have opposite polarities. That is, in this embodiment, the lower end side of the inner and outer rotating permanent magnets (10) is the N pole and the upper end side is the S pole, and the middle rotating permanent magnet (10) is the N pole on the upper end side and the lower end side is the S pole. Has become. Such a permanent magnet magnetic circuit may be another magnetic circuit as long as the floating force of the rotating body can be obtained. For example, the magnetic poles may be arranged in the radial direction of the permanent magnet.

An annular recess (14) having a relatively large radial width is formed in the upper surface (7a) of the bottom wall of the housing (7), and a plurality of fixed permanent magnets (11) are formed in the recess (14). ) And a plurality of non-magnetic rings (15) sandwiched between them are fitted and fixed. The bottom wall of the housing (7) is made of a non-magnetic material such as non-magnetic stainless steel. The fixed permanent magnet (11) also has magnetic poles at both ends in the axial direction, and the magnetic poles at the same end of two adjacent fixed permanent magnets (11) in the radial direction have polarities opposite to each other, and the rotating permanent magnet (10). )
The magnetic pole at the lower end and the magnetic pole at the upper end of the fixed permanent magnet (11) facing the magnetic pole are arranged so as to have the same polarity. That is, in this embodiment, the inner and outer fixed permanent magnets (11) have the N pole at the upper end and the S pole at the lower end, and the middle fixed permanent magnet (11) has the N pole at the lower end and the S pole at the upper end. Has become. And a rotating permanent magnet
The rotating permanent magnet (10) is urged upward by the magnetic repulsive force of the fixed permanent magnet (11) and the fixed permanent magnet (11), which supports the weight of the rotating shaft (1) and causes the rotating shaft (1) to move in the axial direction. It is designed to be supported in a non-contact state by being floated on.

Although not shown in detail in the radial magnetic bearings (3) and (4), the rotary shaft (1) is attracted from both sides in two radial directions (X-axis and Y-axis directions) orthogonal to each other. It has an electromagnet for controlling the position of the rotating shaft (1) in the same direction, and a displacement sensor for detecting the displacement of the rotating shaft (1) 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 attraction force, based on the output of the displacement sensor, and as a result, the rotating shaft (1)
The radial position of is controlled.
Since the radial magnetic bearing and its control device are well known, detailed description is omitted.

Although not described in detail, the generator-motor (6) comprises a rotor mounted on the rotating shaft (1) and a stator fixedly provided on the housing (7) around the rotor. The electric motor (6) operates as an electric motor during storage of electric power to rotate the rotary shaft (1) at a high speed, and operates as a generator during electric power extraction.

Touchdown bearings (16) and (17), which are rolling bearings, are provided on the upper and lower parts of the housing (7) to support the upper and lower ends of the rotary shaft (1) in an emergency.

In the above flywheel device, the rotary shaft (1) is normally supported in a non-contact manner in the axial direction by a permanent magnet bearing (5) and also in a non-contact manner in the radial direction by magnetic bearings (3), (4). It is supported and is rotated at high speed by the generator motor (6) in such a state. Then, while the rotating shaft (1) is rotating at high speed, electric energy is converted into rotational kinetic energy and stored in the flywheel (2).

When a power failure occurs while the rotating shaft (1) is rotating at high speed, the generator motor (6) stops, but the flywheel (2) causes the rotating shaft (1) to decelerate slightly. It is continuously rotated. As a result, generator motor
(6) operates as a generator, and the rotational kinetic energy stored in the flywheel (2) is extracted as electric energy and stored in a storage battery (not shown). The electric power stored in the storage battery is sent to an external electric power consumer product (not shown), and the electric power consumer product continues to operate. Part of the electric power stored in the storage battery is sent to the magnetic bearing control device, which causes the magnetic bearing to
(3) (4) is driven and the radial position control of the rotary shaft (1) is continued. Then, until the rotary kinetic energy stored in the flywheel (2) decreases and the rotary shaft (1) stops, the rotary shaft (1) keeps the magnetic bearings (3) (4) and permanent magnet bearings ( 5) supported by non-contact state.

When the generator motor (6) is stopped even during a power failure, the rotational kinetic energy stored in the flywheel (2) can be taken out as electrical energy, as in the case of a power failure.

In the above flywheel device, the CFRP constituting the reinforcing member (9) fixed to the outer periphery of the flywheel (2) is lightweight and has a large Young's modulus. Since it is lightweight, centrifugal force acting on the reinforcing member (9) at high speed is small, and since Young's modulus is large, deformation (centrifugal expansion) of the reinforcing member (9) due to centrifugal force is small. Therefore, the centrifugal expansion of the flywheel (2) fitted inside the reinforcing member (9) is suppressed to a small level, and the centrifugal destruction of the flywheel (2) is prevented. In addition, one rotary permanent magnet (10) is installed in the annular groove (13) of the flywheel (2) so that each rotary permanent magnet (10) has a wall or partition of the flywheel (2) with small centrifugal expansion. Since they are press-fitted into the inner peripheral portion of the wall (12), the tightening allowance can be reduced, the dimensional control and assembly of the rotary permanent magnet (10) are easy, and moreover, the rotary permanent magnet (10) Centrifugal expansion is suppressed to a low level, and centrifugal breakdown of the rotating permanent magnet (10) is prevented.

In the above embodiment, the flywheel is used.
An annular groove (13) was formed on the lower end surface (2a) of (2) and a rotating permanent magnet (10) was placed there, but as shown in FIG. 3, it is separate from the flywheel (2). Then, fix the disc-shaped non-magnetic rotating member (20) on the rotating shaft (1), and attach the lower end surface of the rotating member (20).
A plurality of annular recessed grooves (13) may be concentrically formed in (20a), and a plurality of annular rotating permanent magnets (10) may be arranged therein. The rotating member (20) is made of a non-magnetic material such as an aluminum alloy or non-magnetic stainless steel and has a disk shape. In this case, by making the rotating member (20) a separate body, the outer diameter of the flywheel (2) can be maximized, while the rotating member (20)
The outer diameter of can be made small, and centrifugal destruction of the rotating permanent magnet (10) can be effectively prevented. Further, it is possible to dispose the flywheel (2) and the rotating member (20) axially separated from each other.

[0025]

As described above, according to the flywheel device of the present invention, the weight of the rotary shaft is supported by the magnetic repulsive force of the rotary permanent magnet on the flywheel side and the fixed permanent magnet on the fixed portion side. The load capacity in the axial direction can be increased, and a heavy rotating shaft that cannot be supported by a superconducting bearing can also be supported. In addition, since the rotating shaft can be supported in the axial direction only by the magnetic repulsive force of the permanent magnet without using a superconducting bearing, the rotation loss can be reduced, energy can be saved, and cost can be reduced. it can.

Since the annular composite fiber reinforced plastic reinforcing member is integrally fixed to the outer periphery of the flywheel or the rotating member, centrifugal expansion of the flywheel or the rotating member is suppressed to a small level, and the flywheel or the rotating member is prevented from expanding. Centrifugal destruction can be prevented.

[Brief description of drawings]

FIG. 1 is a schematic vertical sectional view of a flywheel device showing an embodiment of the present invention.

FIG. 2 is an enlarged vertical sectional view of a portion of the permanent magnet bearing of FIG.

FIG. 3 is an enlarged vertical sectional view of a portion of a permanent magnet bearing of a flywheel device showing another embodiment of the present invention.

[Explanation of symbols]

 (1) Rotating shaft (2) Flywheel (2a) Lower end face (3) (4) 4-axis control radial magnetic bearing (5) Permanent magnet bearing (7) Housing (fixed part) (9) Reinforcing member (10 ) Rotating permanent magnet (11) Fixed permanent magnet (20) Rotating member (20a) Bottom surface

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Shoji Eguchi, 3-5-8 Minamisenba, Chuo-ku, Osaka City Koyo Seiko Co., Ltd.

Claims (2)

[Claims] 1. A rotary shaft that rotates about a vertical shaft, a flywheel fixedly mounted on the rotary shaft, and two sets of upper and lower four-axis control radial magnetic bearings that support the rotary shaft in a non-contact manner in the radial direction. A plurality of annular rotating permanent magnets concentrically laminated on the lower surface of the flywheel or a disc-shaped non-magnetic rotating member fixed to the rotating shaft and having magnetic poles at both axial ends, and the flywheel or A plurality of annular fixed permanent magnets, which are concentrically laminated so as to respectively face the rotary permanent magnets and have magnetic poles at both axial ends, are provided in a fixed portion below the rotary member. The magnetic poles at the same end of the rotary permanent magnet have polarities opposite to each other, and the magnetic pole at the lower end of the rotary permanent magnet and the magnetic pole at the upper end of the fixed permanent magnet opposite thereto have the same polarity. Flywheel apparatus characterized by being adapted to. 2. The flywheel device according to claim 1, wherein an annular composite fiber reinforced plastic reinforcing member is integrally fixed to the outer periphery of the flywheel or the rotating member.