JPH09308185A - Flywheel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce power consumed by an electromagnet and to shorten a shaft. SOLUTION: A vertical shaft 2 equipped with a flywheel 3 is non-contact- supported by a plurality of sets of magnetic bearings 6, 10. In the flywheel 3, tapered bearing surfaces 4, 8 fronting on the opposite side of each other concerning the axial direction are formed at two upper and lower spots of the shaft 2. Magnetic bearings 6, 10 for both axial and radial use having three electromagnets 18 arranged at predetermined intervals in the circumferential direction are provided in a housing 1 around individual bearing surfaces 4, 8, respectively. The magnetic bearings 6, 10 are integrated-with-a-motor type ones which have a motor driving function for rotate-driving the shaft 2.

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 vertical rotating shaft provided with a flywheel is vertically arranged around the vertical rotating shaft.
It is known that a set of radial magnetic bearings and a set of axial magnetic bearings are supported in a non-contact manner, and a rotating shaft is rotationally driven by an electric motor.

In such a conventional flywheel device, two pairs (4 pieces) of radial magnetic bearings are arranged so as to sandwich the rotary shaft from two radial directions orthogonal to each other.
And the axial magnetic bearing is provided with a pair (two) of electromagnets arranged so as to sandwich the flange portion of the rotating body from the axial direction. Therefore, 10 electromagnets are required for the entire apparatus, and there is a problem that the power consumption by the electromagnets is large. Further, since it is necessary to arrange the electric motor and the three sets of magnetic bearings side by side in the axial direction around the rotary shaft, the rotary shaft becomes long. Therefore, the weight of the rotating shaft increases and the natural frequency decreases,
There is a problem that high speed rotation becomes difficult.

In a conventional flywheel device, a hollow vertical rotating body provided with a flywheel is non-contactly supported by upper and lower two sets of radial magnetic bearings and one set of axial magnetic bearings arranged inside thereof, and an electric motor is provided. In some cases, the rotating body is driven to rotate, but in this case, there is the same problem as described above.

The object of the present invention is to solve the above problems,
It is an object of the present invention to provide a flywheel device that can reduce the power consumption by an electromagnet and can shorten the rotating shaft or the rotating body, and can solve the problem caused by the lengthening of the rotating shaft or the rotating body.

[0006]

A flywheel according to the present invention is a flywheel device in which a vertical rotation shaft provided with a flywheel is supported by a plurality of sets of magnetic bearings in a non-contact manner. Tapered bearing surfaces facing opposite to each other in the axial direction are formed at upper and lower two positions on the outer circumference of the rotary shaft, and are arranged at fixed portions in the circumferential direction at fixed portions around the respective bearing surfaces. A magnetic bearing for both axial and radial use provided with three electromagnets is provided, and each of the magnetic bearings has an electric drive function for rotationally driving the rotary shaft.

The rotating shaft is supported in a non-contact manner by two sets of upper and lower magnetic bearings, both axial and radial, provided around the tapered bearing surface. Therefore, the number of magnetic bearings can be reduced by one as compared with the conventional flywheel device in which three sets of magnetic bearings are provided. Moreover, each magnetic bearing has 3
Since it has a three-pole structure consisting of one electromagnet, the number of electromagnets is six, which is four fewer than the conventional flywheel device provided with ten electromagnets. Therefore, the power consumption of the electromagnet can be reduced.
Further, since each magnetic bearing has an electric drive function of rotationally driving the rotary shaft, it is not necessary to separately provide an electric motor. In addition, it is not necessary to separately provide an electric motor around the rotary shaft as described above, and the number of magnetic bearings provided around the rotary shaft is reduced as described above. Therefore, the rotary shaft should be shorter than the conventional one. You can Therefore, the weight of the rotating shaft can be reduced and the natural frequency can be increased, and high speed rotation can be achieved.

For example, an axial auxiliary magnetic bearing for supporting at least a part of the weight of the rotary shaft is provided between the axial end surface of the flywheel and a fixed portion facing the axial end surface. In that case, preferably, the axial auxiliary magnetic bearing includes a permanent magnet provided on a lower end surface of the flywheel, and a permanent magnet provided on the fixed portion so as to repel the permanent magnet.

Since the axial position of the rotating body can be controlled by controlling the axial radial magnetic bearing, the axial auxiliary bearing need only support at least a part of the weight of the rotating shaft. Since at least a part of the weight of the rotating shaft is supported by the axial auxiliary bearing, the power consumption by the electromagnet of the magnetic bearing for both axial and radial can be further reduced.
Even when the axial auxiliary magnetic bearing is composed of an electromagnet, it suffices to support the weight of the rotating shaft, so that it is sufficient to apply a constant exciting current to the electromagnet.
The increase in power consumption due to the electromagnet of the axial auxiliary magnetic bearing can be small. Further, it suffices to provide the electromagnets on the end surface of the flywheel and the facing surface of the fixed portion, and the increase in the length of the rotating shaft due to this is small. When the axial auxiliary magnetic bearing supports the weight of the rotating shaft by the repulsive force of the permanent magnet, there is no increase in power consumption due to the axial auxiliary magnetic bearing. It suffices to provide permanent magnets at and, and the increase in the length of the rotating shaft due to this is small.

The flywheel device according to the present invention is also a flywheel device in which a hollow vertical rotating body provided with a flywheel is supported by a plurality of sets of magnetic bearings in a non-contact manner. A tapered bearing surface facing away from each other with respect to the axial direction is formed, and three electromagnets arranged at predetermined intervals in the circumferential direction are provided in a fixed portion inside each of the bearing surfaces. A magnetic bearing for both axial and radial use is provided, and each of the magnetic bearings has an electric drive function for rotationally driving the rotating body.

Also in this case, similarly to the above, the number of magnetic bearings and electromagnets required is small, and it is not necessary to separately provide an electric motor. Therefore, the power consumption by the electromagnet can be reduced and the rotating shaft can be shortened.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Some embodiments of the present invention will be described below with reference to the drawings.

1 to 3 show an embodiment (first embodiment) in which the present invention is applied to an inner rotor type flywheel device.

As shown in FIG. 1, the flywheel device comprises a housing (fixed portion) (1) and a vertical rotary shaft (2) arranged inside thereof. A flywheel (3) is formed on the outer periphery of the rotary shaft (2) approximately in the center in the vertical direction (axial direction). A tapered taper surface is formed on the outer periphery of the rotary shaft (2) above the flywheel (3) and points obliquely upward, and the large diameter part of the lower half or more of that surface also serves as the rotor part (upper bearing surface) ( 4), the small diameter part near the upper end is the detected surface (upper detected surface) (5).
Magnetic bearing for both axial and radial (upper magnetic bearing) on the inner circumference of the housing (1) facing the upper bearing surface (4)
(6) is the position sensor unit (upper sensor unit) on the inner circumference of the housing (1) facing the upper surface to be detected (5).
(7) is provided. Flywheel with rotary axis (2)
(3) A bearing surface (lower bearing surface) (8) and a surface to be detected (9) which also functions as a rotor portion and faces the opposite side to the upper bearing surface (4) in the axial direction are also provided on the outer periphery below (3). Formed,
A magnetic bearing for both axial and radial (lower magnetic bearing) (1
0) and position sensor unit (lower sensor unit) (1
1) is provided. An axial auxiliary magnetic bearing (13) is provided between the lower end surface of the flywheel (3) and the upwardly facing annular surface (12) of the housing (1) facing the flywheel (3). Annular grooves (14) (15) on the outer circumference of the upper and lower ends of the rotating shaft (2)
And the touchdown bearings (16) and (17) are provided on the inner circumference of the housing (1) corresponding thereto.

The upper magnetic bearing (6) comprises three sets of attraction electromagnets (1
8), which has a three-pole structure, and its details are shown in FIG. These electromagnets (18) are integrally formed in one annular stator portion (19) provided on the inner periphery of the housing (1) at equal intervals (120 degree intervals) in the circumferential direction. Six magnetic poles (18a) protruding inward in the radial direction are integrally formed on the inner circumference of the stator portion (19) at equal intervals (at intervals of 60 degrees) in the circumferential direction. The attraction surface (18b) of each magnetic pole (18a) is a tapered surface corresponding to the bearing surface (4). Two adjacent magnetic poles (18a) form a set of electromagnets (18), and a common suction coil (20) is provided on the tip side of the two magnetic poles (18a) of each set of electromagnets (18). It is rolled.
The magnetic bearing (6) is a motor-integrated magnetic bearing having an electric drive function for rotationally driving the rotating shaft (2), and the motor coil (21) is wound around the base end side of the six magnetic poles (18a). Has been.

The lower magnetic bearing (10) has the same structure as the upper magnetic bearing (6), and corresponding parts are designated by the same reference numerals.

As shown in detail in FIG. 3, the upper sensor unit (7) is arranged so as to sandwich the surface to be detected (5) of the rotary shaft (2) from the outside in the two radial directions orthogonal to each other.
It has a pair (4) of position sensors (22). The detection surface (22a) of each position sensor (22) is a tapered surface corresponding to the detected surface (5).

The lower sensor unit (11) has the same structure as the upper sensor unit (7), and the corresponding parts are designated by the same reference numerals.

The axial auxiliary magnetic bearing (13) is an annular permanent magnet (23) provided on the lower end surface of the flywheel (3).
And the annular surface (12) of the housing (1) facing it
And a ring-shaped permanent magnet (24) provided on the above, and these repel each other.

The suction coil (20) of each electromagnet (18), each magnetic pole (1
The motor coil (21) and the position sensor (22) of 8a) are connected to a control device (not shown), and the control device supplies an alternating current (driving current) to the motor coil (21) as well as the position sensor ( 22) based on the output signal of the suction coil (2
The DC current (excitation current) supplied to 0) is controlled.

In the above flywheel device, by the magnetic repulsive force of the permanent magnets (23) and (24) of the auxiliary magnetic bearing (13),
At least a part of the weight of the rotating shaft (2), preferably substantially the whole, is supported. By supplying a direct current to the suction coil (20) from the control device, the electromagnet (18) attracts the tapered bearing surfaces (4) and (8), and the rotary shaft (2) does not move in the axial and radial directions. Contact supported. By supplying alternating current to the motor coil (21) from the controller, a rotating magnetic field is generated in the stator part (19) and the rotating shaft (2) is driven to rotate, and the magnitude and frequency of this alternating current are controlled. By doing so, the rotational driving force and the rotational speed of the rotary shaft (2) are controlled. Each position sensor (22) outputs a signal corresponding to the size of the gap between the detection surface (22a) of itself and the detected surfaces (5) and (9) facing each other. Then, in the control device, by processing the output signal of the position sensor (22), the position of the rotary shaft (2) in the axial direction and the radial direction is detected, and the suction coil (20) is detected based on the detection result. By controlling the direct current to be supplied, the position of the rotary shaft (2) in the axial direction and the radial direction is controlled.

In the case of the first embodiment, the position sensor unit
(7) (11) detects the position of the rotary shaft (2) by using four position sensors (22), but the electromagnet (18) of the magnetic bearings (6) (10)
Rotation axis using three position sensors arranged in the same way as
It is also possible to detect the position of (2).

FIG. 4 shows another embodiment (second embodiment) in which the present invention is applied to an inner rotor type flywheel device. In the second embodiment, the upper and lower position sensor units (7) and (11) are removed from the first embodiment described above, and corresponding parts are designated by the same reference numerals.

In the case of the second embodiment, the magnetic bearings (6) (10)
Is a so-called sensorless magnetic bearing in which the attraction coil (20) of the electromagnet (18) for supporting the rotating shaft (2) in a non-contact manner is also used as a coil for detecting the position of the rotating shaft (2). Then, the control device detects the position of the rotating shaft (2) in the axial direction and the radial direction based on the change of the exciting current flowing through the attraction coil (20). Others are the same as in the case of the first embodiment.

In the case of the first and second embodiments, the auxiliary magnetic bearing (13) is rotated by the repulsive force of the permanent magnets (23) and (24) on the rotating shaft (2).
Is designed to support the weight of a flywheel
The weight of the rotary shaft (2) may be supported by the attractive force of a permanent magnet provided on the upper end surface of (3) and the downwardly facing annular surface of the housing (1) facing the upper end surface. In addition, the permanent magnet (2
3) Instead of (24), an electromagnet may be provided to support the weight of the rotating shaft (2) by the repulsive force or attractive force of the electromagnet. In some cases, the axial auxiliary magnetic bearing may not be provided.

5 to 7 show an embodiment (third embodiment) in which the present invention is applied to an outer rotor type flywheel device.

As shown in FIG. 5, the flywheel device comprises a vertical fixed shaft (fixed portion) (31) and a hollow vertical rotary body (32) arranged outside thereof. Rotating body (32)
A flywheel (33) is formed on almost the entire height of the outer circumference of the. A bearing surface (upper bearing surface) that has a divergent taper surface that faces diagonally upward is formed in the upper part of the inner circumference of the rotating body (32) inside the flywheel (33), and the lower half or more of the smaller diameter part also serves as the rotor (34), the large-diameter portion near the upper end is the detected surface (upper detected surface) (35). A magnetic bearing for both axial and radial use (upper magnetic bearing) (36) is provided on the outer peripheral portion of the fixed shaft (31) facing the upper bearing surface (34).
A position sensor unit (upper sensor unit) (37) is provided on the outer peripheral portion of the fixed shaft (31) opposed to (5). Similarly, a bearing surface (lower bearing surface) (38 lower) that faces the upper bearing surface (34) in the axial direction and faces the opposite side of the rotor is provided in the lower inner circumference of the rotary body (32) inside the flywheel (33). ) And the surface to be detected (39) are formed, and the axial and radial magnetic bearings (lower magnetic bearing) (40) and the position sensor unit (lower sensor unit) are formed on the outer peripheral portions of the fixed shaft (31) facing each other. ) (41) is provided. Rotating body (32)
Annular step portions (44) and (45) are formed on the inner circumferences of the upper end portion and the lower end portion, respectively, and touchdown bearings (46) (47) are provided on the outer circumference of the fixed shaft (31) corresponding thereto.

The upper magnetic bearing (36) has three sets of attraction electromagnets (4
It has a three-pole structure consisting of 8), and its details are shown in FIG. These electromagnets (48) are integrally formed in one annular stator portion (49) provided on the outer periphery of the fixed shaft (31) at equal intervals (120 degree intervals) in the circumferential direction. Six magnetic poles (48a) protruding outward in the radial direction are integrally formed on the outer periphery of the stator portion (49) at equal intervals (at intervals of 60 degrees) in the circumferential direction. The attraction surface (48b) of each magnetic pole (48a) is a tapered surface corresponding to the bearing surface (34). Two adjacent magnetic poles (48a) form a set of electromagnets (48), and a common suction coil (50) is provided on the tip side of the two magnetic poles (48a) of each set of electromagnets (48). It is rolled.
Further, the magnetic bearing (36) is a motor-integrated magnetic bearing having an electric drive function for rotationally driving the rotating body (32), and the motor coil (51) is wound around the base end side of the six magnetic poles (48a). Has been.

The lower magnetic bearing (40) has the same structure as the upper magnetic bearing (36), and corresponding parts are designated by the same reference numerals.

As shown in detail in FIG. 7, the upper sensor unit (37) is arranged so as to face the surface to be detected (35) of the rotating body (32) from the inside in two radial directions orthogonal to each other. A pair of (4) position sensors (52) are provided. The detection surface (52a) of each position sensor (52) is a tapered surface corresponding to the detected surface (35).

The lower sensor unit (41) has the same structure as the upper sensor unit (37), and the corresponding parts are designated by the same reference numerals.

The suction coil (50) of each electromagnet (48), each magnetic pole (4)
The motor coil (51) and the position sensor (52) of 8a) are connected to a control device (not shown), and the control device supplies an alternating current (driving current) to the motor coil (51) as well as the position sensor ( 52) based on the output signal of the suction coil (5
The DC current (excitation current) supplied to 0) is controlled.

In the above flywheel device, by supplying a direct current to the suction coil (50) from the control device, the electromagnet (48) attracts the tapered bearing surfaces (34) (38),
The rotating body (32) is supported in the axial direction and the radial direction in a non-contact manner. By supplying an alternating current to the motor coil (51) from the control device, a rotating magnetic field is generated in the stator part (49) and the rotating body (32) is driven to rotate, and the magnitude and frequency of this alternating current are controlled. By rotating (32)
The rotational driving force and the rotational speed of are controlled. Each position sensor (52) has a detection surface (35) facing the detection surface (52a) of itself.
The signals corresponding to the size of the gap with (39) are output. Then, in the control device, by calculating the output signal of the position sensor (52), the position of the rotating body (32) in the axial direction and the radial direction is detected, and the suction coil (50) is detected based on the detection result. The position of the rotating body (32) in the axial direction and the radial direction is controlled by controlling the direct current supplied.

Also in the case of the third embodiment, each position sensor unit (37) (41) may detect the position of the rotating body (32) using three position sensors.

FIG. 8 shows another embodiment (fourth embodiment) in which the present invention is applied to an outer rotor type flywheel device. The fourth embodiment is obtained by removing the upper and lower position sensor units (37) and (41) from the above-described third embodiment, and corresponding parts are designated by the same reference numerals.

In the case of the fourth embodiment, the magnetic bearings (36) (40)
Is a so-called sensorless magnetic bearing in which the attraction coil (50) of the electromagnet (48) for supporting the rotating body (32) in a non-contact manner is also used as a coil for detecting the position of the rotating body (32). Then, the control device detects the position of the rotating body (32) in the axial direction and the radial direction based on the change in the exciting current flowing through the attraction coil (50). Others are the same as in the third embodiment.

In the case of the third and fourth embodiments, as in the case of the first and second embodiments, an axial auxiliary magnetic bearing using a permanent magnet, an electromagnet or the like is provided, and the rotating body (3
The weight of 2) may be supported.

The configuration of each part of the flywheel device is not limited to that of the above-described embodiment, but can be changed as appropriate.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a flywheel device showing a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a sectional view taken along line III-III in FIG.

FIG. 4 is a vertical cross-sectional view of a flywheel device showing a second embodiment of the present invention.

FIG. 5 is a vertical cross-sectional view of a flywheel device showing a third embodiment of the present invention.

FIG. 6 is a sectional view taken along line VI-VI of FIG. 5;

7 is a cross-sectional view taken along line VII-VII of FIG.

FIG. 8 is a vertical cross-sectional view of a flywheel device showing a fourth embodiment of the present invention.

[Explanation of symbols]

 (1) Housing (fixed part) (2) Rotating shaft (3) (33) Flywheel (4) (8) (34) (38) Bearing surface (6) (10) (46) (40) Axial radial Magnetic bearings (13) Axial auxiliary magnetic bearings (18) (48) Electromagnets (23) (24) Permanent magnets (31) Fixed shaft (fixed part) (32) Rotating body

Claims (4)

[Claims] 1. A flywheel device for supporting a vertical rotary shaft provided with a flywheel in a non-contact manner by a plurality of sets of magnetic bearings, wherein the flywheel is provided at two upper and lower positions on the outer circumference of the rotary shaft and opposite to each other in the axial direction. A magnetic bearing for both axial and radial use, in which tapered bearing surfaces facing toward the side are formed, and three electromagnets arranged at predetermined intervals in the circumferential direction are provided in a fixed portion around each of the bearing surfaces. A flywheel device, wherein each of the magnetic bearings is provided and has an electric drive function of rotationally driving the rotating shaft. 2. An axial auxiliary magnetic bearing for supporting at least a part of the weight of the rotary shaft is provided between an axial end surface of the flywheel and a fixed portion facing the axial end surface. The flywheel device according to claim 1. 3. The axial auxiliary magnetic bearing comprises a permanent magnet provided on a lower end surface of the flywheel and a permanent magnet provided on the fixed portion so as to repel the permanent magnet. The flywheel device according to claim 2, which is characterized in that. 4. A flywheel device for supporting a hollow vertical rotary body provided with a flywheel by a plurality of sets of magnetic bearings in a non-contact manner, at two positions above and below the inner circumference of the rotary body, which are opposite to each other in the axial direction. A tapered bearing surface facing toward
A magnetic bearing for both axial and radial use provided with three electromagnets arranged at predetermined intervals in the circumferential direction is provided at a fixed portion inside each of the bearing surfaces, and each of the magnetic bearings has the rotation. A flywheel device having an electric drive function of rotationally driving a body.