JPH09233803A - Braking device for high-speed rotating equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To quickly stop a rotary shaft rotating at high speed at emergency by making one a permanent magnet and the other a ferromagnetic substance out of a braked cylinder and a braking cylinder, and bringing about an eddy current accompanying the relative rotation between this ferromagnetic substance and the permanent magnet. SOLUTION: When the drive rod 28 of an actuator 27 is lowered and a braking cylinder 29 is inserted into a braked cylinder 21, a strong magnetic circuit is made between the outside periphery of the ferromagnetic substance 30 existing inside the cylinder 31 and the inside periphery of the permanent magnet 23. In this condition, if the permanent magnet 23 rotates at high speed around the ferromagnetic substance 30, an eddy current is brought about in the cylinder 31 fixed outside the ferromagnetic substance 30, and by this resistance, large braking force is added to the rotary shaft 2 to which the permanent magnet 23 is fixed. Accordingly the rotary shaft 2 and a flywheel 10 can be stopped in emergency.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION A braking device for high-speed rotating equipment according to the present invention is a power storage device that converts surplus power at night into kinetic energy and stores it, and converts this kinetic energy into electrical energy during the daytime to be extracted. It is used in the state of being incorporated in various high-speed rotating machinery such as the superconducting flywheel device that composes.

[0002]

2. Description of the Related Art A flywheel with a large moment is fixed to a rotary shaft as a device which can be installed in a small-scale business office or a general household to store surplus power at night, and a motor also serving as a generator is attached to the rotary shaft. Power storage devices are being researched. In the case of this power storage device, by supplying surplus power to the generator / motor at night, the rotary shaft and the flywheel are rotated, the surplus power is converted into kinetic energy, and the rotary motion of the flywheel is performed. Store as energy. Then, during the daytime, based on this rotational kinetic energy, the electric generator / motor is used to generate electric power, and the electric power is taken out and used.

In order to improve the efficiency of a power storage device using such a flywheel, a bearing device for rotatably supporting the flywheel is used which has a low rotational resistance and a low energy required for operation. There is a need to. Therefore, a power storage device using a superconducting magnetic bearing device as a bearing device has been conventionally proposed as described in Japanese Patent Laid-Open No. 5-248437. FIG.
Shows a power storage device incorporating the superconducting magnetic bearing device described in this publication.

A rotary shaft 2 is arranged vertically in the central portion of a vacuum housing 1 which is hermetically sealed. A holding cylinder 3 is fixed inside the vacuum housing 1 so as to surround the rotary shaft 2. Then, active magnetic bearings 6, 6 composed of magnetic rings 4, 4 and electromagnets 5, 5 are provided between the inner peripheral surface of the lower half of the holding cylinder 3 and the outer peripheral surface of the intermediate portion of the rotary shaft 2, respectively. The rotary shaft 2 is provided so as to be positioned in the radial direction. A rotor 7 is provided between the inner peripheral surface of the upper half of the holding cylinder 3 and the upper end of the rotary shaft 2.
A generator-combined motor 9 including a stator 8 and a stator 8 is provided.

A flywheel 10, which is a rotating member, is fixed to the lower end of the rotary shaft 2, and an annular permanent magnet 11 is fixed to the lower surface of the flywheel 10.
The permanent magnet 11 is magnetized in the axial direction (vertical direction in FIG. 8) and is fixed concentrically with the rotary shaft 2 which is the rotation center of the flywheel 10. Furthermore,
A cooling jacket 12 is fixed to the bottom surface of the vacuum housing 1, and an upper surface of a superconductor 13 provided on an upper surface of the cooling jacket 12 is opposed to a lower surface of the permanent magnet 11. It is desirable that the superconductor 13 has an annular shape similar to the permanent magnet 11 and is arranged concentrically with the permanent magnet 11. However, if it is difficult to make an annular shape, multiple superconductors, each made in a disk shape, arc shape, etc.,
The permanent magnets 11 are arranged at equal intervals on an arc concentric with the permanent magnet 11.
A coolant such as liquid nitrogen is allowed to flow freely in the cooling jacket 12 so that the superconductor 13 can be brought into a superconducting state. When the superconductor 13 is in the superconducting state, the pinning effect prevents the distance between the superconductor 13 and the permanent magnet 11 from changing. Therefore, the superconductor 13 and the permanent magnet 11 form a non-contact type superconducting thrust magnetic bearing 14.

The operation of the conventional power storage device constructed as described above is as follows. When the surplus electric power is stored at night, the rotary shaft 2 and the flywheel 10 are rotated by supplying the surplus electric power to the stator 8 of the generator / motor 9. At this time, the active magnetic bearings 6, 6
By this, positioning of the rotary shaft 2 in the radial direction is achieved, and a coolant is sent into the cooling jacket 12,
The superconductor 13 is cooled. When the superconductor 13 is cooled and is in a superconducting state, the magnetic flux emitted from the permanent magnet 11 is confined in the superconductor 13. The so-called pinning effect causes the permanent magnet 11 to move axially and radially with respect to the superconductor 13. A force that prevents movement in the left-right direction (FIG. 8) acts. By this force, thrust force and radial force acting on the rotary shaft 2 and the flywheel 10 are supported. In this way, the active magnetic bearing 6,
The rotating shaft 2 and the flywheel 10 are supported in a floating state while the superconducting thrust magnetic bearing 14 and the superconducting thrust magnetic bearing 14 are functioning. Therefore, the resistance against the rotation of these two members 2 and 10 is extremely small.

Since the rotational speeds of the rotary shaft 2 and the flywheel 10 gradually increase with the energization of the stator 8, the electric power can be stored in the state of being converted into mechanical kinetic energy. Since the rotating shaft 2 and the flywheel 10 are provided in the vacuum housing 1, the surface of the rotating member and the air do not rub against each other, and once the rotating speed of the flywheel 10 rises, the rotating speed of the generator is increased. Unless the electric power is taken out by the dual-purpose motor 9, it hardly drops. When the stored energy is taken out and used in the daytime, the stator 8 is connected to a load (electric equipment). As a result, electric power is generated in the stator 8 based on the rotational movement of the flywheel 10.

Although not shown, the non-contact type radial bearing for preventing the displacement of the rotary shaft 2 in the radial direction may be a superconducting magnetic bearing. In this case,
The magnetic rings 4, 4 are provided on the outer peripheral surface of the intermediate portion of the rotating shaft 2.
In place of the electromagnets 5 and 5, a superconductor is fixed to the inner peripheral surface of the lower half of the holding cylinder 3 while fixing a diametrically or axially magnetized annular permanent magnet.
A cooling jacket for cooling the superconductor is provided inside the holding cylinder 3.

[0009]

In the electric power storage device as described above, the flywheel 10 and the rotary shaft 2 rotate at an ultrahigh speed during operation. Generally, these flywheels 1
0 and the rotation speed of the rotary shaft 2 decrease due to the resistance generated in the generator / motor 9 portion as the stored electric power is taken out. However, the speed decrease based on this resistance is slow. On the other hand, when an external force is applied due to an earthquake or the like and a portion that rotates at ultra-high speed rubs against the mating surface, it causes a large damage to each component member. Therefore, for example, when an earthquake occurs, it is necessary to stop the flywheel 10 and the rotary shaft 2 in an emergency, but hitherto no braking device capable of performing such an emergency stop has been known.

For example, if a large load (a device with large power consumption) is connected to a portion for taking out electric power by the electric power from the generator-combined motor 9, the resistance of the generator-combined motor 9 increases and the fly The time until the wheel 10 and the rotary shaft 2 stop can be shortened. However, it is not realistic to always prepare such a load for an emergency, and it is not always possible to obtain sufficient braking force.
If the terminals of the generator / motor 9 are short-circuited, a considerably large braking force can be obtained, but the coil of the generator / motor 9 may be burnt out due to heat generation. The braking device for high-speed rotating equipment of the present invention was invented in view of such circumstances.

[0011]

DISCLOSURE OF THE INVENTION A braking device for a high-speed rotating device according to the present invention includes a cylinder to be braked, which is fixed to an end of a rotary shaft of the high-speed rotating device and has a cylindrical first peripheral surface. A braking cylinder having a cylindrical second peripheral surface that can face the first peripheral surface, and a fixed portion that is non-rotatably supported and is capable of advancing and retracting toward the end of the rotary shaft is provided. One of the braked cylinder and the braking cylinder is composed of a permanent magnet magnetized in the diametrical direction, and the magnetized direction is alternately reversed in the circumferential direction. It was done. The other cylinder of the braked cylinder and the brake cylinder includes a ferromagnetic body and an eddy current inducing means for inducing an eddy current in accordance with relative rotation of the ferromagnetic body and the permanent magnet. . As the eddy current inducing means, for example, the following ones can be used alone or in combination. A cylinder made of a good conductive material that is provided so as to cover the peripheral surface of the ferromagnetic material. A plurality of pins, each made of a good conductive material, embedded in the vicinity of the peripheral surface of the ferromagnetic body in the axial direction of the ferromagnetic body, and each of the above pins made of a good conductive material. A basket-shaped member comprising a pair of rings that electrically connect both ends of the. A plurality of concave grooves are formed on the peripheral surface of the ferromagnetic body, each groove extending in the axial direction of the ferromagnetic body.

[0012]

The operation of the braking device for a high speed rotating machine of the present invention constructed as described above is as follows. During normal use of the high-speed rotating device, the braking cylinder is retracted from the braked cylinder.
In this state, the first and second peripheral surfaces do not face each other, and the braking device does not generate any braking force. When a braking force is generated, such as when an emergency stop is performed on a high-speed rotating device, the braking cylinder is advanced toward the braked cylinder so that the first and second peripheral surfaces face each other. In this state, a strong magnetic circuit is formed between the permanent magnet forming one cylinder and the ferromagnetic material forming the other cylinder. Then, as the permanent magnet and the ferromagnetic material rotate relative to each other at a high speed, the ferromagnetic material itself (in the case of) or the cylinder (in the case of) attached to this ferromagnetic material or the cage-shaped member Eddy current is generated. As a result, a large resistance is generated against the relative rotation of the permanent magnet and the ferromagnetic body, and a large braking force is applied to the rotating shaft.

[0013]

1 to 4 and 5 (A) show a first example of an embodiment of the present invention. At the lower end of the rotary shaft 2, a flywheel 1 that rotates together with the rotary shaft 2
0 is fixed concentrically with the rotary shaft 2. A circular ring-shaped permanent magnet 11 is provided at the center of the lower surface of the flywheel 10.
Is fixed. This permanent magnet 11 has an axial direction (see FIGS.
(Up and down direction) is magnetized. The rotary shaft 2 and the flywheel 10 are surrounded by a vacuum housing 1a which is a fixed part. A ring-shaped superconductor 13 is fixed to the upper surface of the bottom of the vacuum housing 1a, and the upper surface of the superconductor 13 and the lower surface of the permanent magnet 11 are opposed to each other. These superconductors 13 and permanent magnets 1
1 constitutes a superconducting magnetic bearing 15, and this superconducting magnetic bearing 15 functions to keep the distance between the flywheel 10 and the vacuum housing 1a constant due to the pinning effect of the superconductor 13. Although not shown, a cooling jacket is incorporated in the bottom of the vacuum housing 1a so that the superconductor 13 can be cooled to a temperature at which it is in a superconducting state.

A cylindrical portion 16 is provided in the upper half of the vacuum housing 1a, and a pair of upper and lower control type magnetic bearings 17 are provided between the inner peripheral surface of the cylindrical portion 16 and the outer peripheral surface of the rotary shaft 2. 17 are provided. For this reason, cylindrical rotors 18 made of a ferromagnetic material such as steel are fixed at two positions above and below the rotary shaft 2. Further, electromagnets 19 and 19 are fixed to portions of the cylindrical portion 16 facing the rotors 18 and 18 at two positions on the inner peripheral surface. Each of these electromagnets 1
Reference numerals 9 and 19 each consist of an electromagnet element divided into four in the circumferential direction. By energizing one of the electromagnet elements based on a signal from a displacement sensor (not shown), the radial position of the rotary shaft 2 is regulated. To do. In the case of this example, the radial rigidity is ensured by providing the control type magnetic bearings 17 having a large radial rigidity in addition to the superconducting magnetic bearing 15. Incidentally, these control type magnetic bearings 17, 1
7 serves to prevent the rotary shaft 2 from swinging in the radial direction when passing a critical speed. After passing the critical speed, the power supply to these control type magnetic bearings 17, 17 is stopped to reduce power consumption.

Further, another rotor 7 is provided in a portion sandwiched by a pair of upper and lower rotors 18, 18 at an intermediate portion of the rotary shaft 2, and a pair of upper and lower electromagnets 19 are provided on an inner peripheral surface of an intermediate portion of the cylindrical portion 16. ,
The stator 8 is fixed to the portions sandwiched by 19 to form a generator / motor 9. This generator / motor 9 has the same structure as the conventional structure shown in FIG.
The rotating shaft 2 and the flywheel 10 are rotated by surplus power at night, and the surplus power is stored as rotational kinetic energy of the flywheel 10. Then, during the daytime, power is generated based on this rotational kinetic energy.

Further, the cylindrical portion 2 is provided at the upper end of the rotary shaft 2.
0 is formed, and the braked cylinder 21 is fitted and fixed inside the cylindrical portion 20. The braked cylinder 21 includes a holding case 22 made of a non-magnetic material in a bottomed cylindrical shape, and a cylindrical permanent magnet 23 arranged inside the holding case 22. The inner peripheral surface of the permanent magnet 23 is a cylindrical first peripheral surface 24. Also, this permanent magnet 23
An even number of segments 25 each formed in an arc shape
It is configured by arranging a and 25b in the circumferential direction. Each of these segments 25a and 25b is magnetized in the diametrical direction.
The magnetization directions of a and 25b are opposite to each other.
Therefore, on the inner and outer peripheral surfaces of the permanent magnet 23, the S pole and the N pole are formed.
The poles are arranged alternately. Such a permanent magnet 23
Is fixed to the inside of the holding case 22 by adhesion or the like. Therefore, the permanent magnet 23 is fixed to the upper end of the rotary shaft 2 and rotates together with the rotary shaft 2.

On the other hand, the top plate 2 of the vacuum housing 1a
An actuator 27 such as an air cylinder is fixed to the lower surface of 6. This actuator 27 is a drive rod 2
8 is fixed to the lower surface of the top plate portion 26 in a state of facing downward, and the drive rod 2 is supplied by supplying and discharging compressed air.
Raise and lower 8. The drive rod 28 never rotates. A braking cylinder 29 is fixed to the lower end of the drive rod 28. The braking cylinder 29 includes a ferromagnetic material 30 such as steel, and a cylinder 31 fitted and fixed to the outer peripheral surface of the ferromagnetic material 30. The cylinder 31 constitutes an eddy current inducing means for inducing an eddy current in accordance with the relative rotation of the permanent magnet 23 and the ferromagnetic body 30, and is made of a good conductive material such as aluminum or copper. In this case,
The outer peripheral surface of the cylinder 31 is the second peripheral surface 38. Such a brake cylinder 29 is inserted inside the braked cylinder 21 as the drive rod 28 descends.
With the rise of the brake cylinder 21, the braked cylinder 21 is retracted above.

When operating the power storage device incorporating the braking device for high-speed rotating equipment configured as described above, for example, without supercooling the superconductor 13, the superconductor 13 is kept in the normal conducting state. A force in an ascending direction is applied to the rotating shaft 2 by a pulling means (not shown), and the flywheel 1
Raise 0 a little. Next, after the superconductor 13 is cooled to bring the superconductor 13 into a superconducting state, the levitation force applied to the rotating shaft 2 is released. As a result,
The rotating shaft 2 and the flywheel 10 are supported in a floating state by a force acting between the superconductor 13 and the permanent magnet 11 based on the pinning force of the superconductor 13 while being slightly lowered due to its weight. It

Then, by energizing the stator 8, the rotary shaft 2 and the flywheel 10 are rotated to store electric power. When taking out the stored electric power, the stator 8 is connected to a load.

When it is necessary to make an emergency stop of the rotary shaft 2 and the flywheel 10 due to an earthquake or the like during the electric power storage performed in this way, the drive rod 28 of the actuator 27 is lowered to bring the braking cylinder into operation. 29 is inserted inside the braked cylinder 21. As a result, the inner peripheral surface of the permanent magnet 23, which is the first peripheral surface 24, and the outer peripheral surface of the cylinder 31, which is the second peripheral surface 38, face each other in a cylindrical shape with a gap. Further, the ferromagnetic body 3 existing on the inner diameter side of the cylinder 31
0 between the outer peripheral surface and the inner peripheral surface of the permanent magnet 23.
A strong magnetic circuit is formed as indicated by the arrow at.

When the permanent magnet 23 rotates at high speed around the ferromagnetic body 30 with such a strong magnetic circuit formed, an eddy current is induced in the cylinder 31 fitted and fixed to the ferromagnetic body 30. To be done. Since this eddy current becomes a resistance against the rotation of the permanent magnet 23, the permanent magnet 23
A large braking force is applied to the rotating shaft 2 that fixes the rotating shaft 2 and the rotating shaft 2 and the flywheel 10 are stopped urgently. The cylinder 31 generates heat during braking, but a vacuum is present between the cylinder 31 and the permanent magnet 23.
The heat transferred to 3 is limited only by radiation. Therefore, the bearing function of the superconducting magnetic bearing 15 will not be lost due to the braking.

As the eddy current inducing means for inducing an eddy current when the permanent magnet 23 rotates around the ferromagnetic material 30 at a high speed, a cylinder 31 made of a good conductive material as in the case of the first example is used. Besides, a basket-shaped member 32 as shown in FIG. 5 (B) or concave grooves 33, 33 as shown in FIG. 5 (C) may be used.

First, the cage member 32 corresponding to the second example of the embodiment of the present invention is provided in the axial direction of the ferromagnetic body 30 (see FIG. 5B) in the vicinity of the outer peripheral surface of the ferromagnetic body 30. A plurality of pins 34, 34, each of which is made of a good conductive material, embedded in the vertical direction), and each of the pins 34, 34 is made of a good conductive material so that both ends of the pins 34, 34 are electrically connected to each other. It is composed of a pair of rings 35, 35. In the case of the structure of the second example as described above, a large braking force can be obtained although the manufacturing work is somewhat troublesome. That is, in the case of this example, a cylinder made of a non-magnetic material, which is a resistance against the flow of magnetic flux, is provided between the inner peripheral surface of the permanent magnet 23 (FIGS. 1 to 4) and the outer peripheral surface of the ferromagnetic body 30. 31 does not exist. Therefore, the magnetic flux density of the magnetic circuit formed between the inner peripheral surface of the permanent magnet 23 and the outer peripheral surface of the ferromagnetic body 30 can be increased to increase the braking force.

The grooves 33, 33 corresponding to the third example of the embodiment of the present invention are formed on the outer peripheral surface of the ferromagnetic body 30 itself in the axial direction of the ferromagnetic body 30 (see FIG. 5C). The vertical direction) is formed directly. In the case of such a structure, mechanical energy is converted into thermal energy by the easiness of the flow of an eddy current generated by the relative rotation between the permanent magnet 23 (FIGS. 1 to 4) and the ferromagnetic body 30, that is, heat generation. In terms of securing efficiency and obtaining a large braking force, it is slightly disadvantageous as compared with the structure shown in FIGS. However, the permanent magnet 23
From the aspect of increasing the magnetic flux density of the magnetic circuit formed between the inner peripheral surface of the and the outer peripheral surface of the ferromagnetic body 30 to secure the braking force, the same effect as the structure shown in FIG. Can be obtained.
Also, the eddy current inducing means can be easily manufactured and the cost is low.

Next, FIGS. 6 to 7 show a fourth example of the embodiment of the present invention. In the case of this example, a small diameter portion 36 is formed at the upper end of the rotary shaft 2, and the permanent magnet 23 is externally fitted and fixed to the small diameter portion 36 via a holding cylinder 37 made of a non-magnetic material. The braking cylinder 29a fixed to the lower end of the drive rod 28 of the actuator 27 is a bottomed cylindrical ferromagnetic body 30a having an opening at the bottom, and is fitted and fixed to the inner peripheral surface of the ferromagnetic body 30a. It is composed of a cylinder 31 made of a good conductive material. In the case of this example, the outer peripheral surface of the permanent magnet 23 is the first peripheral surface 24a, and the inner peripheral surface of the cylinder 31 is the second peripheral surface 38a.

In the case of this example constructed as described above, the first peripheral surface 24 that generates a braking force by facing each other.
Since the diameters of a and the second peripheral surface 38a can be made larger than in the case of the first example described above, the braking torque is increased,
The time required for an emergency stop can be shortened. Other configurations and operations are similar to those of the first example described above.

Although not shown in the drawings, a ferromagnetic cylinder and an eddy current inducing means are provided in a cylinder to be braked provided on the rotary shaft side, and a brake cylinder provided in a fixed portion so as not to rotate includes a permanent magnet. You can also do it.

[0028]

Since the braking device for a high-speed rotating device of the present invention is constructed and operates as described above, various high-speed rotating devices can be urgently braked, and the high-speed rotating device can be used in an emergency such as an earthquake. Can prevent serious damage.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a first example of an embodiment of the present invention in a state where a braking device is not operating.

FIG. 2 is a cross-sectional view showing an upper end portion of a rotary shaft incorporating a brake cylinder.

FIG. 3 is a plan view of the same.

FIG. 4 is a view similar to FIG. 1, showing a state in which a braking device is in operation.

FIG. 5 is a perspective view showing three examples of the structure of a brake cylinder.

FIG. 6 is a cross-sectional view showing a fourth example of the embodiment of the present invention in a state where the braking device is not in operation.

FIG. 7 is a diagram similarly showing a state when the braking device is operating.

FIG. 8 is a vertical cross-sectional view showing a power storage device which is an example of a high-speed rotating device in which the braking device of the present invention is incorporated.

[Explanation of symbols]

 1, 1a Vacuum housing 2 Rotating shaft 3 Holding cylinder 4 Magnetic ring 5 Electromagnet 6 Active magnetic bearing 7 Rotor 8 Stator 9 Generator / motor 10 Flywheel 11 Permanent magnet 12 Cooling jacket 13 Superconductor 14 Superconducting thrust magnetic bearing 15 Superconducting magnetic Bearing 16 Cylindrical part 17 Controlled magnetic bearing 18 Rotor 19 Electromagnet 20 Cylindrical part 21 Braking cylinder 22 Holding case 23 Permanent magnet 24, 24a First peripheral surface 25a, 25b Segment 26 Top plate part 27 Actuator 28 Drive rod 29, 29a Braking cylinder 30, 30a Ferromagnetic material 31 Cylindrical 32 Basket type member 33 Recessed groove 34 Pin 35 Ring 36 Small diameter portion 37 Holding cylinder 38, 38a Second peripheral surface

Claims (1)

[Claims] 1. A braked cylinder having a cylindrical first peripheral surface, which is fixed to an end of a rotary shaft of a high-speed rotating device, and a cylindrical second cylinder which is opposed to the first peripheral surface. And a braking cylinder that has a peripheral surface, is fixed to a non-rotatable portion, and is supported so as to be capable of advancing and retracting toward the end of the rotary shaft, and one of the braked cylinder and the braking cylinder is , A permanent magnet magnetized in the diametrical direction, and the magnetizing directions are alternately reversed in the circumferential direction. The other cylinder is a braking device for high-speed rotating equipment, which is provided with a ferromagnetic body and an eddy current inducing means for inducing an eddy current in accordance with relative rotation of the ferromagnetic body and the permanent magnet.