JPH09121478A - Flywheel energy storage apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce an iron loss and an eddy current loss by a method wherein the permanent magnets of rotor members which are so arranged in the axial direction of a shaft as to have different poles face each other and the coils of stator members which are so placed as to be perpendicular to the axial direction are made to face each other with gaps therebetween and, at the time of a high speed rotation, a rotary system is supported in a non-contact state by dynamic pressure bearings. SOLUTION: A rotor member 6 is composed of a plurality of permanent magnets 6a which are so arranged as to have different poles appear alternately in the circumferential direction of a plane perpendicular to the axial direction of a shaft 5 and has a shape of a disc having a center hole. A plurality of the disc-shaped rotor members 6 are arranged so as to have the shaft 5 through the center holes and so as to have the different poles of the respective rotor members 6 face each other in the axial direction with gaps therebetween. A stator member 8 is composed of a plurality of flat coils which are arranged in a plane perpendicular to the axial direction of the shaft 5 with certain intervals. The coils are made to face the permanent magnets 6a in the axial direction with gaps therebetween. Further, a rotary system which is composed of the shaft 5, a rotor 7 and a flywheel 3 is supported in a non-contact state by dynamic pressure bearings 13 which are provided on the middle part and lower end part of the shaft 5 at the time of a high speed rotation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an energy storage device for, for example, an uninterruptible power supply for a computer power supply, a household power supply, a power supply for an electric vehicle, etc., and in particular, electric energy in the form of kinetic energy. The present invention relates to a flywheel type energy storage device which is stored at, converted into electric energy and supplied when necessary.

[0002]

2. Description of the Related Art FIG. 2 is a vertical sectional front view of an essential part showing an example of a conventional flywheel type energy storage device, which is disclosed in, for example, Japanese Patent Laid-Open No. 2-36740. In FIG. 2, reference numeral 50 denotes a vacuum casing, which is formed in a hollow cylindrical shape with a bottom and is provided with a mounting portion 50a on the outer circumference. Reference numeral 51 denotes a casing, which is fixed to the vacuum casing 50 with bolts 53, and a ceiling plate 54 is further fixed to the casing 51.

A stator frame 57 is fixed to the center of the bottom of the vacuum casing 50.
7, a stator core 58 formed by laminating thin steel plates
Is provided and the coil 59 is wound. A pivot bearing 55 is provided in the stator frame 57, and is configured to rotatably support a pivot shaft 56, which is a component of a rotating body described later. The pivot shaft 56 is configured to be in a non-contact state with the pivot bearing 55 due to the high pressure of the lubricating oil due to the groove pump action due to the high speed rotation.

Next, a needle bearing 60 is provided on the upper end portion of the stator core 57 in order to suppress the swing of the pivot shaft 56. A mounting plate 61 is fixed to the upper end of the pivot shaft 56.
Reference numeral 62 denotes a rotor core, which is formed by stacking thin disc-shaped steel plates, has a large number of slot portions provided in the inner peripheral portion in the axial direction, and conductors such as aluminum are injected into these slot portions. The upper and lower ends of 62 are short-circuited to form an end ring 63.

The rotor core 62 is provided with a gap from the stator core 58, and the upper end of the end ring 63 is fixed to the mounting plate 61. Reference numeral 64 denotes a flywheel, which is formed by winding a piano wire many times and is fixed to the end ring 63. And the pivot shaft 5
6, the mounting plate 61, the rotor core 62, the end ring 63, and the flywheel 64 are integrated to form a rotating body 65 having the pivot shaft 56 as its axis.

The above-mentioned stator core 58 and coil 5
9, the rotor core 62 and the end ring 63 configure the generator-motor unit as an induction machine. Reference numeral 66 denotes a protector, which is provided on the inner circumference of the vacuum casing 50 and serves to protect the device when the flywheel 64 is undesirably broken. Reference numeral 67 denotes an attracting magnet, which is fixed to the casing 51 through a gap with the mounting plate 61 and serves to balance the rotation of the rotating body 65 by a magnetic attraction force between the attracting magnet and the mounting plate 61.

With the above structure, when the coil 59 of the stator core 58 is energized from the outside, a magnetic induction action is generated between the stator core 58 and the rotor core 62, and the rotating body 65 rotates at high speed with the pivot shaft 56 as the axis.
The flywheel 64 rotating at a high speed stores electric energy in the form of kinetic energy, converts the kinetic energy into electric energy when necessary, and supplies the electric power to the load.

[0008]

In the above-mentioned conventional apparatus, since the generator motor section is constructed as an induction machine, the conversion efficiency between electric energy and kinetic energy is low (for example, 80% or less). There is a point. That is, since the stator core 58 and the rotor core 62 made of a steel material are used in the magnetic circuit, iron loss occurs due to alternating magnetic fields. In order to reduce such iron loss, thin iron steel plates which are insulated from each other are stacked to form the stator core 58 and the rotor core 62, and further, a silicon steel plate or the like with less iron loss is used. The loss has not been significantly reduced.

On the other hand, if the cross-sectional area of the coil 59 and the aluminum conductor is increased in order to increase the capacity of the induction machine, an eddy current is generated in the coil 59 and the aluminum conductor, and the conversion efficiency is reduced due to the eddy current loss. Will be a factor. In particular, the higher the magnetic flux density and the higher the frequency used in the alternating magnetic field, the larger the eddy current loss generated in the coil 59 and the aluminum conductor, and the conversion efficiency is further reduced.

Further, in the above-mentioned conventional apparatus, the rotating body 65
The pivot shaft 56 constituting the
Although the bearing is supported by the needle bearing 60, the rotary member 65 rotates at a high speed, so that the supporting means is required to have high accuracy. However, since the needle bearing 60 is in rolling contact with the pivot shaft 56, the needle bearing 60 is engaged in a frictional state, so that friction loss naturally occurs and causes a decrease in energy exchange efficiency. Further, since the pivot shaft 56 is supported in the vicinity of the upper end portion thereof, when vibration or other external force is applied to the device, the pivot shaft 56 may make a so-called scouring motion, which is undesired for the needle bearing 60. There is a problem that the unbalanced load acts and the life is shortened.
As a result, the rotation of the rotating body 65 becomes unstable, which also contributes to the reduction in energy conversion efficiency.

The present invention solves the above-mentioned problems existing in the prior art, and provides a flywheel type energy storage device having extremely small iron loss and eddy current loss and capable of greatly improving energy conversion efficiency. Is an issue.

[0012]

In order to solve the above problems, in the present invention, a rotor and a flywheel constituting a generator motor are coaxially fixed to a shaft, and the shaft is rotated to generate electricity. In a flywheel type energy storage device that converts energy into kinetic energy and stores it, and when needed, converts this kinetic energy into electrical energy and supplies it as electric power to a load,
In a generator-motor, a hollow disk-shaped rotor member provided with a plurality of permanent magnets so that different poles alternately appear in a circumferential direction of a plane orthogonal to the axis of the shaft is arranged so that the different poles face each other in the axial direction. And a stator member formed into a hollow disc shape by equipping a plurality of flattened coils at equal intervals in the circumferential direction of a plane orthogonal to the axis. And a permanent magnet of the rotor member and a coil of the stator member are provided so as to face each other in the axial direction with a gap therebetween, and the axis line of the shaft is formed vertically, and the shaft, the rotor, and A technical means is adopted in which a rotary system composed of a flywheel is configured to be supported in a non-contact state at high speed rotation by dynamic pressure bearings provided at the middle and lower ends of the shaft. It was.

In the present invention, n stator members (n
Is a positive integer of 1 or more), and (n + 1) rotor members can be provided.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a longitudinal sectional view of an essential part showing an embodiment of the present invention. In FIG. 1, reference numeral 1 is a vacuum container, which is formed in a hollow cylindrical shape with a bottom, and in which a generator motor 2 and a flywheel 3 are provided. 4 is a lid plate, which is a vacuum container 1
Is provided above and holds the inside of the vacuum container 1 in a vacuum state. A vacuum hose (not shown) communicating with the vacuum unit is connected to the vacuum container 1.

Next, in the generator motor 2, a hollow disk-shaped rotor member 6 is fixed to a shaft 5 whose axis is formed vertically, and the hollow portion is fixed to the shaft 5, for example, four in the axial direction. For example, three hollow disk-shaped stator members 8 are provided between the rotor 7 and the rotor members 6 and 6 that are spaced apart from each other so as to face each other in the axial direction with a gap. And the stator 9. The flywheel 3 is integrally fixed to the shaft 5.

The shaft 5 is integrally provided at its lower end with a pivot 10 formed, for example, in a hemispherical shape, and is rotatably supported by a pivot bearing 11 provided at the center of the bottom of the vacuum container 1. The intermediate portion of the shaft 5 is supported by the dynamic pressure bearing 13. A plurality of grooves are provided in the portion of the pivot 10 facing the dynamic pressure bearing 13 of the shaft 5, and each of the pivot bearings is caused by the high pressure of the lubricating oil caused by the groove pump action due to the high speed rotation of the shaft 5. 11 and the dynamic pressure bearing 13 can be maintained in a non-contact state. Therefore, the pivot 10 and the pivot bearing 11 are a kind of dynamic pressure bearing. Next, the dynamic pressure bearing 13 is provided at an intermediate portion of the shaft 5, but is preferably provided at a position of the center of gravity of the rotary system including the flywheel 3 or a position in the vicinity thereof.

Reference numeral 12 denotes a touchdown bearing, which is provided at the center of the cover plate 4 and faces the shaft 5 at the upper end of the shaft 5 with a gap of, for example, about 0.5 mm. The touchdown bearing 12 is not in contact with the shaft 5 under normal conditions, but supports the upper end of the shaft 5 when the flywheel 3 is undesirably broken or destroyed.

Next, the rotor member 6 is formed into a hollow disk shape by providing a plurality of permanent magnets 6a so that different poles appear alternately in the circumferential direction of the plane orthogonal to the axis of the shaft 5. The shaft 5 is provided in the hollow portion with a gap so that the shaft 5 penetrates through the gap and the different poles face each other in the axial direction. The permanent magnet 6a is made of a rare earth magnet material having a large magnetic energy product, for example, an Nd-Fe-B magnet material. The uppermost rotor member 6 and the lowermost rotor member 6 each have a yoke 6 made of a ferromagnetic material.
b is provided.

The stator 9 is constructed by providing a stator member 8 via a spacer 15 in a casing 14 formed in a hollow cylindrical shape. Reference numeral 16 denotes a lid plate, which is provided above the casing 14 and the dynamic pressure bearing 13 is provided at the center thereof. A plurality of flat coils are provided on the stator member 8 at equal intervals in the circumferential direction of a plane orthogonal to the axis of the shaft 5. These coils are wound, for example, in a substantially trapezoidal shape when projected on a plane, are arranged for each phase of U, V, W, and deviate the electrical angle between each phase, and are laminated in three phases. Formed into a structure.
The coil is provided so as to face the permanent magnet 6a in the axial direction with a gap.

The coil has a cross section of, for example, a plurality of thin bare copper wires each having a diameter of 0.16 mm.
A conductor having a rectangular shape of 1.2 mm × 2.3 mm and a coating made of oily enamel, for example, is wound around the outer periphery of the conductor in a flat shape to form an air core (coreless shape).

Next, the flywheel 3 is formed by winding a high-strength fiber such as glass fiber, carbon fiber, etc., a high-strength steel wire, etc. a large number of times, and a flange portion 3a having a relatively large volume on the outer periphery and the flange portion 3a. It is integrally configured with a rim portion 3b formed in the shape of a hollow disc on the inner periphery, and the shaft 5 is provided via the rim portion 3b.
To be fixed.

Reference numeral 17 denotes a magnetic bearing, which is a supporting permanent magnet 18a provided on the upper surface of the outer peripheral portion of the cover plate 16 and a holding plate 1 fixed to the lower surface of the rim portion 3b of the flywheel 3.
9 and a supporting permanent magnet 18b provided on the base plate 9. The supporting permanent magnets 18a and 18b are formed, for example, in a ring shape around the axis of the shaft 5, and are provided so that the same poles face each other with a gap.

As described above, the shaft 5, the rotor member 6, the flywheel 3, the holding plate 19 and the supporting permanent magnet 18b constitute a rotary system having the shaft 5 as its axis, and the weight of the rotary system is It is supported by the pivot 10, the pivot bearing 11, and the magnetic bearing 17.

Reference numeral 21 denotes a closed container, which is provided in a recess in the central portion of the cover plate 4 and is closed by a ceiling plate 22 above. Reference numeral 23 is a getter. For example, a support member supports a thin wire made of zirconium or a zirconium alloy, and the thin wire can be electrically heated from the outside. Since the closed container 21 communicates with the vacuum container 1 through the gap between the touchdown bearing 12 and the shaft 5, the inside of the vacuum container 1 becomes a vacuum and the inside of the closed container 21 can also be kept at a vacuum.

With the above structure, when the coil of the stator member 8 is energized from an external AC power source, the permanent magnet 6a and the coil magnetically attract and repel the shaft 5 from the rotor 7, the flywheel 3 and the like. Since the rotating system rotates at a high speed of, for example, 30000 rpm or more, this rotating system stores electric energy in the form of kinetic energy, converts this kinetic energy into electric energy when necessary, and supplies it to an external load. Can be supplied as.

In this case, since the magnetic flux penetrates the permanent magnet 6a and the coil of the stator member 8 substantially parallel to the axis of the shaft 5, no iron material is present in the magnetic circuit. Therefore, the occurrence of iron loss can be eliminated as compared with the conventional one. The coils forming the stator member 8 are
As described above, since the conductor that is formed in the air core and that forms the coil is an assembly of thin wires, the eddy current generated in the conductor is extremely small, and the eddy current loss can be significantly reduced.

The rotary system having the flywheel 3 and the rotor 7 as components is housed in the vacuum container 1, and the getter 23 is provided in the closed container 21 communicating with the vacuum container 1. Therefore, the inside of the vacuum container 1 can be maintained at a predetermined degree of vacuum for a long period of time. That is, when the degree of vacuum is lowered after the initial vacuum treatment of the vacuum container 1, the getter 23 is heated by energization to be activated to react with the gas such as hydrogen, nitrogen and oxygen in the vacuum container 1. Therefore, the degree of vacuum can be maintained at a predetermined level. Therefore, even when the rotating system rotates at a high speed of, for example, 30,000 rpm or more, the wind loss can be greatly reduced.

Further, the dynamic pressure bearing 13 and the pivot bearing 11 which support the rotating system generate a high pressure in the lubricating oil by the groove pump action during the high speed rotation of the rotating system or the shaft 5, and the shaft 5 and the pivot 10 are respectively provided. Since the non-contact state is maintained, friction loss is prevented, stability is good even when external force such as vibration acts, and as a result, energy conversion efficiency can be improved. As a result of the above, it was confirmed experimentally that a conversion efficiency of 98% was obtained.

[0029]

EFFECTS OF THE INVENTION Since the present invention has the structure and operation as described above, the following effects can be obtained.

(1) Since the loss such as iron loss, eddy current loss and wind loss is extremely small, the energy conversion efficiency can be greatly improved. (2) Since the intermediate part of the shaft is supported by the dynamic pressure bearing, the stability of the rotary system is good even when vibration or other external force acts.

(3) The device can be made smaller and lighter, and a large amount of energy can be stored. (4) The time required for energy storage is short and maintenance is easy.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a main part showing an embodiment of the present invention.

FIG. 2 is a vertical sectional front view of an essential part showing an example of a conventional flywheel type energy storage device.

[Explanation of symbols]

 1 Vacuum container 3 Flywheel 5 Shaft 7 Rotor 9 Stator

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Isao Takahashi 4-46-3 Kitayama-cho, Nagaoka City, Niigata Prefecture

Claims (2)

[Claims] 1. A rotor and a flywheel constituting a generator motor are coaxially fixed to a shaft, and by rotating the shaft, electric energy is converted into kinetic energy and stored, and this kinetic energy is converted into electricity when necessary. In a flywheel type energy storage device that converts energy into electricity and supplies it to a load as electric power, a generator motor is provided with multiple permanent magnets so that different poles appear alternately in the circumferential direction of a plane orthogonal to the axis of the shaft. A rotor having a hollow disk-shaped rotor member formed in such a way that the different poles face each other in the axial direction with a gap, and a plurality of flatly formed coils in the circumferential direction of a plane orthogonal to the axis. And a permanent magnet of the rotor member, and a stator including a stator member formed in a hollow disk shape at equal intervals. The coil of the stator member is provided so as to be opposed to each other in the axial direction with a gap, and the axis of the shaft is formed vertically, and a rotary system composed of the shaft, the rotor and the flywheel is provided at the middle portion and the lower end portion of the shaft. A flywheel type energy storage device, characterized in that it can be supported in a non-contact state at high speed rotation by the provided dynamic pressure bearing. 2. The flywheel energy storage device according to claim 1, wherein n stator members (n is a positive integer of 1 or more) are provided, and (n + 1) rotor members are provided.