JP2002310154A - Permanent magnet magnetic circuit and superconductive bearing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a permanent magnet magnetic circuit for a superconductive bearing device capable of suppressing demagnetization in application on which a strong demagnetic field is applied for a long time and application where a permanent magnet is increased in temperature high. SOLUTION: A permanent magnet magnetic circuit 60 used in an axial type superconductive bearing device is formed that first - fourth annular permanent magnets 62a-62d which are different in inside and outside diameters from each other are concentrically situated. First - fifth annular yokes 64a-64e different in inside and outside diameter from each other though they have the same thicknesses are nipped between the first - fourth annular permanent magnets 62a-62d. A pair of adjoining annular permanent magnets on the inner peripheral side and the outer peripheral side are situated such that the same poles are positioned opposite to each other. The thicknesses of the first - fifth yokes are set to specified sizes (=t1 ) and the thicknesses (=t4 ) of the second and third annular permanent magnets are set larger than the thicknesses (=t5 ) of the first and fourth annular permanent magnets.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor, various actuators, a generator, a motor for an electric vehicle, and a power storage device for converting surplus power into kinetic energy of a flywheel for storage. The present invention relates to a permanent magnet magnetic circuit and a superconducting bearing device in which it is important to generate a magnetic field. In particular, the present invention is effective for a permanent magnet magnetic circuit and a superconducting bearing device having a structure in which permanent magnets have a repulsive structure to generate a high magnetic field and strongly receive a demagnetizing field due to a magnetic field from an opposing permanent magnet.

[0002]

2. Description of the Related Art As an apparatus provided with the permanent magnet magnetic circuit, for example, Japanese Patent Application Laid-Open No. 12-230551 shown in FIGS.
An axial type superconducting bearing device (referred to as device 2 of the prior art 1) described in Japanese Patent Application Laid-Open No. 08-17778 shown in FIG.
A radial type superconducting bearing device (referred to as a device 30 of the prior art 2) described in Japanese Patent Application Publication No. 856 is known.

The apparatus 2 of the prior application 1 shown in FIGS. 28 and 29 is equipped with a permanent magnet magnetic circuit (referred to as a magnet section in the publication) 4 and a rotating body section 6 which rotates around a rotating shaft section 18. A permanent magnet magnetic circuit 4 that generates a magnetic flux in an axial direction along a rotating shaft 18 and a rotating shaft of the superconductor 8, the fixed body 10 having a superconductor 8 mounted below the rotating body 6. The rotating body 6 is fixed to the fixed body 10 by utilizing the repulsive force of
It is configured to be supported in a non-contact state with respect to.
In the figure, reference numeral 12 denotes a cooler connected to the holding unit 14, and reference numeral 16 denotes a control unit for controlling the cooler 12, and the superconductor 8
Is controlled by the holding unit 14, the cooler 12, and the control unit 16.
It is cooled to a temperature that meets the required conditions.

[0004] The rotating body 6 includes the rotating shaft 18 described above,
A disk portion 20 mounted on the rotating shaft portion 18;
And a penetrating member 22 through which the rotating shaft 18 penetrates the center. The permanent magnet magnetic circuit 4 is supported by the disc 20 and the penetrating member 22. Permanent magnet magnetic circuit 4
A plurality of annular permanent magnets 24a to 24d having the same thickness and different inner and outer diameters are concentrically arranged, and the annular soft magnetic bodies 26a having the same thickness and different inner and outer diameters are arranged. To 26e are sandwiched between the annular permanent magnets 24a to 24d, or on the inner peripheral side and the outer peripheral side, respectively.
Alternatively, they are arranged in close contact with each other and the annular soft magnetic body 26b
A pair of annular permanent magnets on the inner peripheral side and the outer peripheral side adjacent to each other via 26d are disposed so that the same poles face each other.

[0005] Further, an apparatus 30 of prior art 2 shown in FIG.
The ring-shaped rotating body 3 is provided on the outer periphery of the cylindrical fixed body 32.
4 are opposed to each other, and a superconductor 38 provided on the fixed body portion 32 is provided.
This is a device in which the rotating body portion 34 is rotatable by a pinning effect with a permanent magnet magnetic circuit 48 provided in the rotating body portion 34, and these are housed in a housing (not shown).

That is, a cylindrical cooling case 36 supported and fixed to the housing is provided in the housing.
On the outer diameter side of the cooling case 36, a support body 40 in which an annular superconductor 38 is embedded is fixed. In the figure, reference numeral 42 denotes a refrigerator for cooling the cooling case 36, and reference numeral 44 denotes a refrigerator.
Is a temperature control unit for controlling the temperature of the refrigerator. The rotator portion 34 includes an annular rotator 46 housed in the housing and a permanent magnet magnetic circuit 48 fixed to the inner peripheral side of the rotator 46, and has the same inner and outer diameters. The plurality of annular permanent magnets 50a to 50e and the annular soft magnetic bodies 52a to 52d having the same inner and outer diameters as the annular permanent magnets 50a to 50e are alternately overlapped in the axial direction, and via the annular soft magnetic bodies 52a to 52d. A pair of annular permanent magnets adjacent to each other in the axial direction are arranged so that the same poles face each other. It is generally known that when permanent magnets face each other with the same polarity, their own magnetic field exerts a negative magnetic field (this is referred to as a demagnetizing field) on the opposing permanent magnets, which makes it easy to demagnetize. It is also known that this configuration is liable to be demagnetized (this is called thermal demagnetization) even at a temperature rise.

[0007]

By the way, the inventors of the present invention have proposed an axial type superconducting bearing having the same configuration as that shown in FIG. 28 in a power storage device for converting surplus power into kinetic energy of a flywheel and storing it. The performance test of the superconducting bearing device for a long time operation (cumulatively about 1110 hours) was conducted by incorporating the device.

In the axial type superconducting bearing device, the permanent magnet magnetic circuit generates a repulsive force in the direction of the rotation axis facing the superconductor. However, a change in the magnetic field strength leads to a change in the repulsive force. In turn, it affects bearing performance. From the results of the performance test described above, when driving for a long time,
As shown in FIG. 31, it has been found that a portion where the magnetic field strength of the permanent magnet magnetic circuit 4 is reduced (demagnetized) occurs, which adversely affects the bearing performance.

That is, FIG. 31 is a diagram showing the measurement results of the magnetic field strength of the permanent magnet magnetic circuit 4 before and after long-time operation, and the vertical axis of this figure indicates the magnetic field strength [T].
The horizontal axis indicates the distance (radial position) from the center of the rotating shaft portion 18 of the permanent magnet magnetic circuit 4 on the side facing the superconductor 8 in FIG. 28 to the outer peripheral side. Here, the measurement gap length is 2 mm.

As is apparent from FIG. 31, there is a portion where the magnetic field strength after the operation is reduced by about 20% at the maximum as compared with that before the operation. It was found that the magnetic field intensity at the center peak among the five magnetic field intensity peaks arranged in the direction was reduced by 21.1% and demagnetized. However, the magnetic field intensity on the inner peripheral side or the outer peripheral side of the permanent magnet magnetic circuit 4 hardly changes (about 1.3%), and there is no demagnetization.

To clarify this factor, as shown in the schematic diagram of FIG. 32, a soft magnetic material Ms having a constant thickness t1 (= 2 mm) and a permanent magnet Mp having a constant thickness t2 (= 8 mm) are used. A permeance coefficient at a specific position of the permanent magnet Mp in the permanent magnet magnetic circuit (width t3 is set to 20 mm) in which permanent magnets Mp were joined alternately and faced with the same polarity of each other was determined by computer analysis.

According to this, the permeance coefficient at the point A closest to the other permanent magnet Mp is 0.265, the permeance coefficient at the point B at the center in the thickness direction is 0.301, and The permeance coefficient at point C not facing the permanent magnet Mp is 0.329. The place where the permeance coefficient is small is a place where the magnetic field strength is reduced and demagnetized, and the place where the permeance coefficient is large is a place where the magnetic field strength is not reduced and not demagnetized. Therefore, the point A closest to the other permanent magnet Mp is easily demagnetized, and the point C which is not opposed to the other permanent magnet Mp is a place that is hardly demagnetized.

When the relationship shown in FIG. 32 is applied to the permanent magnet magnetic circuit 4 shown in FIG. 28, as shown in FIG. 33, the radial direction in which the same poles are opposed to other annular permanent magnets, as shown in FIG. Annular permanent magnets 24b, 24 located at the center of
“c” indicates that the permeance coefficient is small on both the inner and outer peripheral sides to easily demagnetize (large demagnetization), and the radially innermost or outermost annular permanent magnets 24a and 24d
Means that the permeance coefficient on the side not facing other annular permanent magnets is large, making it difficult to demagnetize (small demagnetization)
It becomes a magnetic circuit.

As described above, in the axial type superconducting bearing device 2, the permanent magnet magnets arranged with a limited size facing the superconductor 8 so as not to adversely affect the performance of the bearing supporting the flywheel. An important issue is how to suppress the demagnetization of the circuit 4. On the other hand, when the radial type superconducting bearing device 30 of FIG. 30 is incorporated in an electric power storage device, as shown in FIG. 34, the center in the axial direction in which the same poles face other annular permanent magnets. The permanent magnets 50b and 50c located on the upper side and the lower side have low permeance coefficients and are easily demagnetized (large demagnetization). In addition, the permeance coefficient on the side not facing the other annular permanent magnet is increased, so that the permanent magnet magnetic circuit 48 is hardly demagnetized (small demagnetization). Therefore, in order not to adversely affect the performance of the bearing supporting the flywheel, it is an important issue how to suppress the demagnetization of the permanent magnet magnetic circuit 48 which is arranged with a limited size facing the superconductor 38. It has become.

The present invention has been made in view of the above circumstances, and provides a permanent magnet magnetic circuit in which it is important to stably generate a high magnetic field strength for a long time and a superconducting bearing device having the same. It is intended to be. Further, the permanent magnet magnetic circuit is effective and sufficiently applicable to motors, various actuators, generators, and electric vehicle motors that are used for a long time at high temperatures.

[0016]

Means for Solving the Problems The present inventors have paid attention to the permeance coefficient p in a magnetic circuit as means for suppressing demagnetization of a permanent magnet magnetic circuit. Considering the permeance coefficient p with reference to the model of the magnetic circuit shown in FIG. 35, the magnetic field strength at the operating point of the permanent magnet: Hd, the magnetic flux density at the operating point of the permanent magnet: Bd, the cross-sectional area of the gap: Sg, Assuming that the length of the air gap is Lg, the cross-sectional area of the permanent magnet is Sm, the length of the permanent magnet is Lm, the magnetic permeability of air is μ, the leakage coefficient is σ, and the reluctance coefficient is r.

[0017]

(Equation 1)

The following relationship is obtained. Therefore, in order to increase the permeance coefficient p, assuming that the first term (σ · μ / r) of the equation (1) is constant, the second term (Sg · L
m) / (Sm · Lg) may be increased.
Assuming that the cross-sectional area Sm of the permanent magnet does not change and therefore the cross-sectional area Sg of the air gap does not change, the permeance coefficient p becomes
The ratio of the length Lm of the permanent magnet to the length Lg of the gap (Lm / L
g).

The permeance coefficient p is equal to the length L of the permanent magnet.
The difference between m and the length Lg of the gap (Lm / Lg) is determined by the fact that the soft magnetic material Ms and the permanent magnet Mp according to the present invention are alternately joined, and the same poles of the permanent magnets Mp face each other. Considering the permanent magnet magnetic circuit shown in FIG. 36, the thickness t2 of the permanent magnet is increased or the thickness t2 of the soft magnetic material is increased.
1 is increased, the thickness t2 of the permanent magnet and the length L of the air gap are increased.
The ratio to g is greater than 1 and the permeance coefficient increases.

As described above, by increasing the thickness t2 of the permanent magnet or the thickness t1 of the soft magnetic material, or increasing both the thickness t2 of the permanent magnet and the thickness t1 of the soft magnetic material. Thus, the permeance coefficient p can be increased,
As a result, a permanent magnet magnetic circuit that is hardly demagnetized can be obtained. Further, as another means for suppressing the demagnetization of the permanent magnet magnetic circuit, it is conceivable to use a permanent magnet made of a material having a large coercive force. It has also been found that the configuration makes it possible to obtain a circuit that is hardly demagnetized.

Therefore, in the permanent magnet magnetic circuit according to the first aspect of the present invention, a plurality of permanent magnets are arranged side by side with a soft magnetic material interposed therebetween, and the permanent magnets are adjacent to each other via the soft magnetic material. In the permanent magnet magnetic circuit in which the same poles of the permanent magnets face each other, the permeance coefficient at the center in the direction in which the permanent magnet and the soft magnetic material are arranged is set to a large value.

According to a second aspect of the present invention, in the permanent magnet magnetic circuit, the permanent magnet and the soft magnetic material are arranged at the center in the arrangement direction of the permanent magnet at the end in the arrangement direction. Larger than the size of the permanent magnets to be arranged. Further, in the permanent magnet magnetic circuit according to the third aspect, the size of the permanent magnet and the soft magnetic body in the arrangement direction of the soft magnetic body located at the center in the arrangement direction may be set to the size of the soft magnet positioned at the end in the arrangement direction. It was made larger than the dimension in the direction in which the magnetic bodies were arranged.

According to a fourth aspect of the present invention, in the permanent magnet magnetic circuit, the permanent magnet positioned at the center in the direction in which the permanent magnet and the soft magnetic material are arranged is more than the permanent magnet positioned at the end in the direction in which the soft magnets are arranged. The coercive force has a large characteristic. Further, the permanent magnet magnetic circuit according to claim 5 is:
The dimension of the permanent magnet located in the central part of the arrangement direction of the permanent magnet and the soft magnetic material in the arrangement direction is made larger than the dimension of the permanent magnet located at the end of the arrangement direction, and The size of the soft magnetic material located at the center in the direction of arrangement is made larger than the size of the soft magnetic material located at the end in the direction of arrangement.

According to a sixth aspect of the present invention, in the permanent magnet magnetic circuit, the permanent magnet and the soft magnetic material are arranged at the center in the arrangement direction of the permanent magnet in the arrangement direction at the end in the arrangement direction. The permanent magnets located at the center in the arrangement direction are larger than the permanent magnets located at the ends in the arrangement direction. did.

According to a seventh aspect of the present invention, in the permanent magnet magnetic circuit, the size of the permanent magnet and the soft magnetic material in the arrangement direction of the soft magnetic material located at the center in the arrangement direction is set at the end in the arrangement direction. The permanent magnets located at the center in the arrangement direction have a larger coercive force than the permanent magnets located at the ends in the arrangement direction, while being larger than the size of the soft magnetic material located in the arrangement direction. I did it.

In the permanent magnet magnetic circuit according to the present invention, the dimension of the permanent magnet located in the center of the permanent magnet and the soft magnetic material in the direction in which the permanent magnets are aligned may be set at the end in the direction of the alignment. The size in the arrangement direction of the soft magnetic material located at the center in the arrangement direction is made larger than the size in the arrangement direction of the soft magnetic material located at the end in the arrangement direction. At the same time, the permanent magnet located at the center in the arrangement direction has a characteristic that the coercive force is larger than that of the permanent magnet located at the end in the arrangement direction.

On the other hand, the superconducting bearing device according to claim 9 is
9. The permanent magnet and the soft magnetic body are formed in an annular body, and the permanent magnet and the soft magnetic body are arranged side by side in the radial direction with the arrangement direction being a radial direction orthogonal to a rotation axis. 10. Is a device in which any one of the permanent magnet magnetic circuits is disposed so as to be rotatable relative to the superconductor. Further, in the superconducting bearing device according to claim 10, the permanent magnet and the soft magnetic body are formed in an annular body, and the permanent magnet and the soft magnetic body are aligned in the axial direction with the arrangement direction being an axial direction along a rotation axis. An apparatus in which the permanent magnet magnetic circuit according to any one of claims 1 to 8, which is arranged in layers, is arranged on a superconductor so as to be relatively rotatable.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A permanent magnet magnetic circuit according to the present invention will be described below with reference to the drawings. FIG. 28
30 are denoted by the same reference numerals and the description thereof will be omitted. FIG. 1 shows a permanent magnet magnetic circuit of the first embodiment used as a permanent magnet magnetic circuit of the axial type superconducting bearing device 2 shown in FIG.

The permanent magnet magnetic circuit 60 of this embodiment has first to fourth annular permanent magnets 62a to 62d having different inner and outer diameters arranged concentrically, and has the same size and inner and outer diameters. The first to fifth annular yokes (annular soft magnetic bodies) 64a to 64e having different
Between the fourth to fourth annular permanent magnets 62a to 62d, or between the fourth and fourth annular permanent magnets 62a to 62d, or between the fourth and fourth annular permanent magnets 62a to 62d. The pair of annular permanent magnets on the side and the outer periphery are arranged so that the same poles face each other.

In the present embodiment, the thickness of the first to fifth yokes 64a to 64e is set to a fixed size (= t1), and the first to fourth annular permanent magnets 62a are set.
To 62d, the second and third positions located at the radial center.
Thickness of the annular permanent magnets 62b and 62c (= t4)
Is set to be larger than the magnet thickness (= t5) of the first and fourth annular permanent magnets 62a and 62d located on the radial end side.

It is a feature of the present invention that the thickness of the magnet at the center (= t4) is made larger than the thickness of the magnet at the end (= t5). As a result of intensive studies, by setting t4> 1.5 × t5,
More desirably, t4> 2 × t5 is an effective magnetic circuit with a small amount of demagnetization. As in this embodiment, the second and third annular permanent magnets 6 located at the center in the radial direction
If the thicknesses of the second and third annular permanent magnets 62b and 62c are set to be larger than the thicknesses of the first and fourth annular permanent magnets 62a and 62d located on the radial end side, respectively.
Even if the permeance coefficient p of b and 62c increases and a strong demagnetizing field acts locally or the temperature of the permanent magnet may rise due to some factor, the center of the permanent magnet magnetic circuit 60 in the radial direction is The structure becomes hard to be demagnetized.

Thus, the second and third annular permanent magnets 6
Since the permeance coefficients p of 2b and 62c are large and the permeance coefficients p of the first and fourth annular permanent magnets 62a and 62d are not small, the permanent magnet magnetic circuit 60 is hard to be demagnetized over the entire area in the radial direction. When the permanent magnet magnetic circuit 60 is provided in the axial type superconducting bearing device 2, the permanent magnet magnetic circuit 6 facing the superconductor 8 is provided.
Since 0 always generates a constant magnetic field strength, deterioration of bearing performance can be prevented. For example, the device is suitable for a power storage device that converts surplus power into kinetic energy of a flywheel and stores it.

Next, FIG. 2 shows a permanent magnet magnetic circuit of a second embodiment used as a permanent magnet magnetic circuit of the axial type superconducting bearing device 2. The permanent magnet magnetic circuit 66 of the present embodiment has first to fourth annular permanent magnets 66a to 66 having the same thickness (= t2) and different inner and outer diameters.
6d are arranged concentrically, and the first to fifth annular yokes 6
8a to 68e are connected to first to fourth annular permanent magnets 66, respectively.
a to 66d, or between the inner circumference side and the outer circumference side, or disposed in close contact therewith, and the second to fourth yokes 68b to
A pair of inner and outer annular permanent magnets adjacent to each other via 68d are arranged so that the same poles face each other.

In this embodiment, the thicknesses of the second, third, and fourth yokes 68b, 68c, 68d located at the radial center of the first to fifth yokes 68a to 68e ( = T6) is set to be larger than the thickness (= t1) of the first and fifth yokes 68a, 68e located on the radial end side. It is a feature of the present invention that the thickness of the yoke at the center (= t6) is larger than the thickness of the yoke at the end (= t1). The inventors have intensively studied the thickness. As a result, by setting t1> 2 × t2, and more preferably t1> 3 × t2, an effective magnetic circuit with a small amount of demagnetization is obtained.

As in the present embodiment, the second, third and fourth yokes 68b, 68c, which are located at the radial center,
The thickness (= t6) of the first and fifth yokes 68a and 68e (= t6) located on the radial end side
1) When the size is set to be larger, the permeance coefficient p of the second and third annular permanent magnets 66b and 66c increases, and even if a strong demagnetizing field acts locally, or the temperature of the permanent magnets rises for some reason. However, the center of the permanent magnet magnetic circuit 66 in the radial direction has a structure that is hardly demagnetized.

Thus, the second and third annular permanent magnets 6
Since the permeance coefficients p of 6b and 66c are large and the permeance coefficients p of the first and fourth annular permanent magnets 66a and 66d are not small, the permanent magnet magnetic circuit 66 is hard to be demagnetized over the entire area in the radial direction. Therefore, when this permanent magnet magnetic circuit 66 is provided in the axial type superconducting bearing device 2, the permanent magnet magnetic circuit 66 facing the superconductor 8 always generates a constant magnetic field strength, thereby preventing a decrease in bearing performance. can do.

Next, FIG. 3 shows a permanent magnet magnetic circuit of a third embodiment used as a permanent magnet magnetic circuit of the axial type superconducting bearing device 2. The permanent magnet magnetic circuit 70 of the present embodiment has first to fourth annular permanent magnets 72a to 72 having the same thickness (= t2) and different inner and outer diameters.
2d are arranged concentrically, and the first to fifth annular yokes 74a to 74e having the same thickness (= t1) are respectively disposed between the first to fourth annular permanent magnets 72a to 72d, or A pair of inner and outer ring-shaped permanent magnets that are sandwiched or closely attached to the inner and outer peripheral sides and are adjacent to each other via the second to fourth yokes 74b to 74d are connected to each other. They are arranged so that the poles face each other.

In the present embodiment, the material of the second and third annular permanent magnets 72b and 72c located at the center in the radial direction among the first to fourth annular permanent magnets 72a to 72d is changed to the diameter. The first and fourth annular permanent magnets 72a and 72d located on the end side in the direction have higher coercive force than the material of the first and fourth annular permanent magnets 72a and 72d. Thus, the coercive force (Hc
It is a feature of the present invention to make 1) larger than the coercive force (Hc2) of the permanent magnet at the end. As a result of the inventor's intensive studies on the size, Hc1> 1.2 × Hc
2, more preferably, Hc1> 1.3.
XHc2 provides an effective magnetic circuit with a small amount of demagnetization.

As in the present embodiment, the second and third annular permanent magnets 72b and 72c located at the center in the radial direction are
By using a material having a higher coercive force than the first and fourth annular permanent magnets 72a and 72d located on the radial end side,
A structure in which the radial center of the permanent magnet magnetic circuit 70 is hardly demagnetized is obtained. Thus, the permanent magnet magnetic circuit 70 is hardly demagnetized over the entire area in the radial direction.

Therefore, when the permanent magnet magnetic circuit 70 is provided in the axial type superconducting bearing device 2, the permanent magnet magnetic circuit 70 facing the superconductor 8 always generates a constant magnetic field strength, and therefore the bearing performance is reduced. The drop can be prevented. Further, in the embodiment described with reference to FIGS. 1 to 3, that is, in the radial center, the thicknesses of the second and third annular permanent magnets 62b and 62c located at the radial center are set to be large. Located at the second, third and fourth
The thicknesses of the yokes 68b, 68c, 68d are set to be large, and the second and third annular permanent magnets 72b, 72c located at the radial center are made of a material having a high coercive force. When the configuration is combined with the configuration, the configuration combined with the configuration, the configuration combined with the configuration, and the configuration combined with each other, it is possible to obtain a permanent magnet magnetic circuit that is less likely to be demagnetized over the entire area in the radial direction.

In the permanent magnet magnetic circuits shown in FIGS. 1 to 3, the yokes are arranged on the innermost side and the outermost side. Can be obtained. On the other hand, FIG.
31 is a permanent magnet magnetic circuit of a fourth embodiment used as a permanent magnet magnetic circuit of the radial type superconducting bearing device 30 shown in FIG. 30.

The permanent magnet magnetic circuit 76 of the present embodiment has first to fourth annular permanent magnets 78a to 78a having the same inner and outer diameters.
8d, and first to fifth annular yokes (annular soft magnetic bodies) having the same inner and outer diameters as the annular permanent magnets 78a to 78d.
80a to 80e are alternately overlapped in the axial direction, and a pair of annular permanent magnets adjacent in the axial direction via the yokes 80a to 80e are arranged so that the same poles face each other.

In the present embodiment, the thickness of the first to fifth yokes 80a to 80e is set to a fixed size (= t1), and the first to fourth annular permanent magnets 78a are set.
To 78d, the second and the third positioned at the center in the axial direction.
The thickness (= t4) of the ring-shaped permanent magnets 78b, 78c is larger than the thickness (= t5) of the first and fourth ring-shaped permanent magnets 78a, 78d located on the axial end side. You have set. The configuration of the present embodiment is assumed to be the configuration.

As in the present embodiment, the thicknesses of the second and third annular permanent magnets 78b and 78c located at the center in the axial direction are the same as those of the first and second annular permanent magnets located at the axial end. If the dimension is set to be larger than the thickness of the fourth annular permanent magnets 78a, 78d, the permeance coefficient p of the second and third annular permanent magnets 78b, 78c increases, and even if a strong demagnetizing field acts locally, Alternatively, even if the temperature of the permanent magnet rises for some reason, the radial center of the permanent magnet magnetic circuit 76 has a structure that is hardly demagnetized.

Thus, the second and third annular permanent magnets 7
Since the permeance coefficients p of 8b and 78c are large and the permeance coefficients p of the first and fourth annular permanent magnets 78a and 78d are not small, the permanent magnet magnetic circuit 76 is hard to be demagnetized over the entire area in the axial direction. When the permanent magnet magnetic circuit 76 is provided in the radial type superconducting bearing device 30, the permanent magnet magnetic circuit 76 facing the superconductor 38 always generates a constant magnetic field strength, so that the deterioration of the bearing performance can be prevented. For example, a device suitable for a power storage device that converts surplus power into kinetic energy of a flywheel and stores the converted kinetic energy can be obtained.

Although not shown, the thicknesses of the first to fourth annular permanent magnets 78a to 78d are made constant, and the second, third, and fourth yokes 80b, 80c,
When the thickness of 80d is made larger than the thickness of the other yokes, the permeance coefficient p of the second and third annular permanent magnets 78b and 78c increases, and the first and fourth annular permanent magnets 78a and 78d become Since the permeance coefficient p does not decrease, it is possible to obtain a permanent magnet magnetic circuit that is hardly demagnetized over the entire area in the axial direction. Note that this configuration is referred to as the configuration.

Further, the first to fourth annular permanent magnets 78a
The first to fifth yokes 80a
The thickness of the second and third annular permanent magnets 78b and 78c located at the center in the axial direction is also changed to the first and fourth annular permanent magnets 78 at the axial end.
Even if the coercive force is higher than that of the materials a and 78d, a permanent magnet magnetic circuit that is hardly demagnetized over the entire area in the axial direction can be obtained. Note that this configuration is referred to as the configuration.

In the above-mentioned configuration, the configuration combining the above, the configuration combining the above, the configuration combining the above, and the configuration combining all of the above configurations can further reduce permanent magnetism over the entire area in the axial direction. A magnet magnetic circuit can be obtained. In each of the above embodiments, a permanent magnet magnetic circuit is used for a device that supports a rotating body such as a superconducting bearing device. However, the present invention is applied to, for example, a linear motor device that operates linearly and one-dimensionally or two-dimensionally. The use of a permanent magnet magnetic circuit results in an optimal permanent magnet magnetic circuit that is hardly demagnetized.

In the permanent magnet magnetic circuit according to the fourth embodiment shown in FIG. 4, the yokes are arranged at the uppermost portion and the lowermost portion. Obtainable.

[0050]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Although there are various causes of demagnetization of a permanent magnet magnetic circuit, here, in order to quickly confirm the effects of the present invention,
Create a plurality of models of the permanent magnet magnetic circuit according to the present invention,
It was decided to raise the ambient temperature of those models to forcibly generate thermal demagnetization. First, the strength of the magnetic field was measured at room temperature of 20 ° C. After that, the model of the permanent magnet magnetic circuit was left in a temperature-controlled electric furnace for 90 minutes to increase the temperature, and then cooled to room temperature to temporarily reduce the magnetic field. The strength was measured. The set temperatures are 50 ° C, 70 ° C, 90 ° C, 110 ° C,
The same operation was performed at 130 ° C., 150 ° C., and 170 ° C. to measure the magnetic field strength.

The model shown in FIG. 5 uses NEOMAX44H (trade name: Sumitomo Special Metals Co., Ltd.) as the material of the permanent magnet.
), And SS as the material of the yoke (soft magnetic material)
400 were used. The permanent magnet located at the center in the arrangement direction uses two kinds having a thickness L1 of 8 mm and 16 mm, and the thickness of the permanent magnet located at the end in the arrangement direction is 8 mm.
And the thickness of the yoke was set to 2 mm.

As shown in FIG. 5, the measurement gap of the probe of the Gauss meter was set to 2 mm.
The test was performed at the positions of yoke numbers 1 to 5. As is clear from the measurement results in FIGS. 6 to 8, the thickness of the permanent magnet at the center in the arrangement direction is increased as compared to the model in which the thicknesses of the permanent magnets are all uniform (the thickness is 8 mm) ( The model with a thickness of 16 mm) can obtain the effect of being less likely to be demagnetized. Next, the model shown in FIG. 9 is made of the same material as the material shown in the model of FIG.
Two types having a thickness t of 2 mm and 6 mm were used. The thickness of the yokes located at the ends in the arrangement direction was set to 2 mm, and the thicknesses of the permanent magnets were all set to 8 mm. Then, similarly to the model of FIG. 5, the magnetic field intensity was measured at the positions of the yoke numbers 1 to 5 by using a Gauss meter probe with the measurement gap set to 2 mm.

As is clear from the measurement results of FIGS. 10 to 12, the thickness of the central yoke in the arrangement direction is increased compared to the model in which the thicknesses of the yokes are all uniform (the thickness is 2 mm). (Thickness: 6mm) The model is reduced even if a strong demagnetizing field is applied to the permanent magnet for some reason, or even if the temperature of the permanent magnet becomes high due to the rise in ambient temperature or heat generated by the eddy current generated in the permanent magnet itself. The effect of being hard to magnetize is obtained.

Next, the measurement results shown in FIGS.
As shown in FIG. 3 described above, this is a measurement result of a model in which the thickness of all yokes is made uniform and the coercive force of the permanent magnet is changed. That is, the measurement results indicated by ■ in these figures are based on the assumption that the central permanent magnet in the arrangement direction has a high coercive force (NEOMAX39SH (trade name: Sumitomo Special Metals Co., Ltd.)
And the permanent magnets at the ends in the direction of alignment have low coercive force (NEOMAX44H). In addition, the measurement results indicated by ◆ in these figures indicate that all the permanent magnets have a low coercive force (NEOMAX44H).

As is apparent from FIGS. 13 to 15, when the permanent magnet in the center in the arrangement direction has a high coercive force, when a strong demagnetizing field is applied to the permanent magnet for some reason or when the temperature of the surroundings increases. Also, even if the temperature of the permanent magnet becomes high due to the heat generated by the eddy current generated in the permanent magnet itself, it is possible to obtain an effect that it is difficult to demagnetize. Next, FIGS.
The measurement results shown in (1) and (2) show a model in which the thickness of the central permanent magnet in the arrangement direction is increased and the thickness of the center yoke in the arrangement direction is increased (the measured values of this model are indicated by ■ in the figure). (A permanent magnet and a yoke having a uniform thickness in the arrangement direction, and measured values indicated by ◆ in these figures). The yoke numbers 2, 3, and 4 correspond to the yoke numbers in FIG.

As is apparent from FIGS. 16 to 18, by increasing the thickness of the central permanent magnet in the arrangement direction and increasing the thickness of the central yoke in the arrangement direction, demagnetization is more difficult. The effect is obtained. Next, the measurement results shown in FIGS. 19 to 21 are based on a model in which the thickness of the central permanent magnet in the arrangement direction is increased and the coercive force of the central permanent magnet in the arrangement direction is increased. (Shown by ■ in the figure)
7 is a result of comparison between a conventional model (a permanent magnet and a yoke having a uniform thickness in the arrangement direction and measured values indicated by ◆ in these figures).

As is apparent from FIGS. 19 to 21, the demagnetization is further reduced by increasing the thickness of the central permanent magnet in the arrangement direction and increasing the coercive force of the central permanent magnet in the arrangement direction. The effect of being difficult is obtained. Next, FIG.
The measurement result shown in FIG. 23 is a model in which the thickness of the central yoke in the arrangement direction is increased and the coercive force of the permanent magnet in the center in the arrangement direction is increased (the measured values of this model are indicated by ■ in the figure).
7 is a result of comparison between a conventional model (a permanent magnet and a yoke having a uniform thickness in the arrangement direction and measured values indicated by ◆ in these figures).

As is apparent from FIGS. 22 to 23, the thickness of the central yoke in the arrangement direction is increased, and the coercive force of the central permanent magnet in the arrangement direction is increased. The effect is obtained. Further, FIG.
The measurement results shown in FIG. 27 show a model in which the thickness of the central permanent magnet in the arrangement direction is increased, the thickness of the central yoke in the arrangement direction is increased, and the coercive force of the central permanent magnet in the arrangement direction is increased. (The measured values of this model are indicated by ■ in the figure) and the results of a comparison between the conventional model (a permanent magnet and a yoke having uniform thickness in the arrangement direction, and the measured values indicated by ◆ in these figures) is there.

By increasing the thickness of the central permanent magnet in the arrangement direction, increasing the thickness of the central yoke in the arrangement direction, and increasing the coercive force of the central permanent magnet in the arrangement direction, FIG. As shown in (1), the magnetic field intensity hardly changes in the measurement portion of the yoke 3, and the effect of further reducing the demagnetization is obtained. The degree of the demagnetization and the strength of the magnetic field may be appropriately adjusted depending on the use of the permanent magnet magnetic circuit of the present invention. The adjustment of the magnetic field strength can be performed by selecting an appropriate permanent magnet material or by setting the ratio of the thickness of the permanent magnet to the thickness of the yoke to an appropriate ratio between 90:10 and 50:50. .

As the material of the permanent magnet used in the present invention, in addition to the above-mentioned NdFeB magnet such as NEOMAX, SmCo ₅ magnet, Sm ₂ Co ₁₇ magnet, ferrite magnet, alnico magnet, and these bond magnets is there. The soft magnetic material (yoke) used in the present invention is made of soft magnetic iron, permalloy, permengel, SS-41, Si
Fe is suitable.

[0061]

As described above, according to the permanent magnet magnetic circuit of the first aspect, the permeance coefficient at the central portion in the direction in which the permanent magnet and the soft magnetic material are arranged is set to a large value. Even when a strong demagnetizing field is applied to the permanent magnet, or even when the temperature of the permanent magnet becomes high due to an increase in ambient temperature or heat generated by an eddy current generated in the permanent magnet itself, the central portion of the magnetic circuit is hardly demagnetized. In addition, the permeance coefficient on the end side in the direction in which the permanent magnet and the soft magnetic material are arranged is difficult to decrease, so if a strong demagnetizing field is applied to the permanent magnet for some reason, or if the ambient temperature rises or the permanent magnet itself occurs Even if the temperature of the permanent magnet becomes high due to the heat generated by the eddy current, the end portion is hardly demagnetized. This makes it possible to obtain a permanent magnet magnetic circuit that is hard to be demagnetized over the entire area in the arrangement direction, and that a high-performance magnetic circuit can be obtained even in applications where a strong demagnetizing field is applied for a long time, or in applications where the temperature of the permanent magnet is high. .

According to the second aspect of the present invention, the dimension of the permanent magnet located at the center in the arrangement direction of the permanent magnet and the soft magnetic material in the arrangement direction is set to be equal to the dimension of the arrangement direction of the permanent magnet located at the end of the arrangement direction. Because it is larger than the dimensions, the permeance coefficient at the center in the alignment direction becomes a large value.
A permanent magnet magnetic circuit that is hardly demagnetized can be obtained over the entire area in the arrangement direction, and a high-performance magnetic circuit can be obtained even in an application in which a strong demagnetizing field is applied for a long time or an application in which the permanent magnet is heated to a high temperature.

According to the third aspect of the present invention, the dimension of the soft magnetic material located at the center in the arrangement direction of the permanent magnet and the soft magnetic material in the arrangement direction is made equal to the arrangement of the soft magnetic material located at the end in the arrangement direction. Since the dimension is larger than the dimension in the direction, the permeance coefficient in the central part in the direction of alignment becomes a large value.Therefore, it is possible to obtain a permanent magnet magnetic circuit that is difficult to demagnetize over the entire area in the direction of alignment, and a strong demagnetizing field is applied for a long time. A high performance magnetic circuit can be obtained even in applications or applications where the temperature of the permanent magnet is high.

According to the fourth aspect of the present invention, the permanent magnet located at the center in the arrangement direction of the permanent magnet and the soft magnetic material has a characteristic that the coercive force is larger than that of the permanent magnet located at the end in the arrangement direction. This makes it possible to obtain a permanent magnet magnetic circuit that is hard to demagnetize over the entire area in the arrangement direction, and is a high-performance magnetic circuit even in applications where a strong demagnetization field is applied for a long time or where the temperature of the permanent magnet is high. Can be obtained.

According to the fifth to eighth aspects of the present invention, since the permeance coefficient at the central portion in the arrangement direction has a larger value, a permanent magnet magnetic circuit which is harder to demagnetize over the entire area in the arrangement direction is obtained. be able to. According to the superconducting bearing device of the ninth aspect, the permanent magnet and the soft magnetic material are formed in an annular body, and the permanent magnet and the soft magnetic material are arranged side by side in the radial direction with the arrangement direction being the radial direction orthogonal to the rotation axis. Since the permanent magnet magnetic circuit according to any one of claims 1 to 8 is disposed so as to be rotatable relative to the superconductor, the permeance coefficient at the central portion in the radial direction has a large value, and the permeance coefficient is reduced over the entire area in the radial direction. A permanent magnet magnetic circuit that is difficult to magnetize will be provided, and the performance of the permanent magnet magnetic circuit arranged in a limited size facing the superconductor will be improved, so that the performance of the axial type superconducting bearing device will be improved. be able to.

Further, according to the superconducting bearing device of the tenth aspect, the permanent magnet and the soft magnetic material are formed in an annular body,
The permanent magnet magnetic circuit according to any one of claims 1 to 8, wherein the permanent magnet and the soft magnetic material are arranged in layers in the axial direction with the arrangement direction being the axial direction along the rotation axis. , The permeance coefficient at the central part in the axial direction is large, and a permanent magnet magnetic circuit that is hard to demagnetize over the entire area in the axial direction is provided. Since the performance of the permanent magnet magnetic circuit arranged as described above is improved, the performance of the radial type superconducting bearing device can be improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing a permanent magnet magnetic circuit used in an axial type superconducting bearing device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a permanent magnet magnetic circuit used in an axial type superconducting bearing device according to a second embodiment of the present invention.

FIG. 3 is a view showing a permanent magnet magnetic circuit used in an axial type superconducting bearing device according to a third embodiment of the present invention.

FIG. 4 is a diagram showing a permanent magnet magnetic circuit used in a radial type superconducting bearing device according to a fourth embodiment of the present invention.

FIG. 5 is a model diagram showing a first embodiment according to the present invention.

FIG. 6 is a first diagram illustrating measurement results of the first example.

FIG. 7 is a second diagram showing the measurement results of the first example.

FIG. 8 is a third diagram showing measurement results of the first example.

FIG. 9 is a model diagram showing a second embodiment according to the present invention.

FIG. 10 is a first diagram illustrating measurement results of the second example.

FIG. 11 is a second diagram illustrating measurement results of the second example.

FIG. 12 is a third diagram showing the measurement results of the second example.

FIG. 13 is a first diagram illustrating measurement results of the third example.

FIG. 14 is a second diagram showing measurement results of the third example.

FIG. 15 is a third diagram showing the measurement results of the third example.

FIG. 16 is a first diagram illustrating measurement results of the fourth example.

FIG. 17 is a second diagram illustrating measurement results of the fourth example.

FIG. 18 is a third diagram illustrating measurement results of the fourth example.

FIG. 19 is a first diagram illustrating measurement results of the fifth example.

FIG. 20 is a second diagram illustrating measurement results of the fifth example.

FIG. 21 is a third diagram showing the measurement results of the fifth example.

FIG. 22 is a first diagram illustrating measurement results of the sixth example.

FIG. 23 is a second diagram showing the measurement results of the sixth example.

FIG. 24 is a third diagram showing the measurement results of the sixth example.

FIG. 25 is a first diagram illustrating measurement results of the seventh example.

FIG. 26 is a second diagram illustrating measurement results of the seventh example.

FIG. 27 is a third diagram illustrating measurement results of the seventh example.

FIG. 28 is a view showing an axial type superconducting bearing device.

FIG. 29 is a diagram showing a permanent magnet magnetic circuit constituting the axial type superconducting bearing device.

FIG. 30 is a view showing a radial type superconducting bearing device.

FIG. 31 is a diagram showing locations where demagnetization occurs in a conventional permanent magnet magnetic circuit.

FIG. 32 is a diagram showing calculated values of permeance coefficients.

FIG. 33 is a diagram showing positions where demagnetization occurs in the permanent magnet magnetic circuit of the axial type superconducting bearing device.

FIG. 34 is a diagram showing positions where demagnetization occurs in a permanent magnet magnetic circuit of a radial type superconducting bearing device.

FIG. 35 is a model diagram of a permanent magnet magnetic circuit.

FIG. 36 is a diagram illustrating the flow of magnetic flux of the permanent magnet magnetic circuit according to the present invention.

[Explanation of symbols]

 2 Axial type superconducting bearing device 30 Radial type superconducting bearing device 60, 66, 70, 76 Permanent magnet magnetic circuit 62a to 62d Ring permanent magnet (permanent magnet) 64a to 64e Yoke (soft magnetic material) 66a to 66d Ring permanent magnet (Permanent magnet) 68a-68e Yoke (soft magnetic material) 72a-72d Ring permanent magnet (permanent magnet) 74a-74e Yoke (soft magnetic material) 78a-78d Ring permanent magnet (permanent magnet) 80a-80e Yoke (soft magnetic material) T1, t6 Thickness of yoke t2, t4, t5 Thickness of annular permanent magnet

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Akihito Uetake 3-5-3 Yamato, Suwa-shi, Nagano Seiko Epson Corporation (72) Inventor Hitoshi Yamamoto 3-13-2 Takada 3-chome, Toshima-ku, Tokyo Sumitomo F-term in Technical Development Division, Special Metals Co., Ltd. (reference)

Claims (10)

[Claims] 1. A permanent magnet magnet comprising: a plurality of permanent magnets arranged side by side with a soft magnetic material interposed therebetween, and facing the same poles of the permanent magnets adjacent to each other via the soft magnetic material. In the circuit, a permeance coefficient at a central portion in a direction in which the permanent magnet and the soft magnetic material are arranged is set to a large value. 2. A permanent magnet magnet comprising: a plurality of permanent magnets arranged side by side with a soft magnetic material interposed therebetween, and facing the same poles of the permanent magnets adjacent to each other via the soft magnetic material. In the circuit, the permanent magnet and the soft magnetic body are arranged such that the dimension in the arrangement direction of the permanent magnet located at the center in the arrangement direction is larger than the dimension in the arrangement direction of the permanent magnets located at the end in the arrangement direction. Features permanent magnet magnetic circuit. 3. A permanent magnet magnet comprising a plurality of permanent magnets arranged side by side with a soft magnetic material interposed therebetween, and facing the same poles of the permanent magnets adjacent to each other via the soft magnetic material. In the circuit, the dimension in the arrangement direction of the soft magnetic material located at the center in the arrangement direction of the permanent magnet and the soft magnetic material is larger than the dimension in the arrangement direction of the soft magnetic material located at the end in the arrangement direction. A permanent magnet magnetic circuit, characterized in that: 4. A permanent magnet magnet comprising a plurality of permanent magnets arranged side by side with a soft magnetic material interposed therebetween, and facing the same poles of the permanent magnets adjacent to each other via the soft magnetic material. In the circuit, the permanent magnet located at the center in the direction in which the permanent magnet and the soft magnetic material are arranged has a characteristic that the coercive force is larger than that of the permanent magnet located at the end in the direction in which the magnets are arranged. And a permanent magnet magnetic circuit. 5. A permanent magnet magnet comprising a plurality of permanent magnets arranged side by side with a soft magnetic material sandwiched therebetween, and facing the same poles of the permanent magnets adjacent to each other via the soft magnetic material. In the circuit, the dimension of the permanent magnet located in the central part of the arrangement direction of the permanent magnet and the soft magnetic material in the arrangement direction is larger than the dimension of the permanent magnet located at the end of the arrangement direction, and A permanent magnet magnetic circuit, wherein a dimension in the arrangement direction of the soft magnetic material located at the center in the arrangement direction is larger than a dimension in the arrangement direction of the soft magnetic material located at an end in the arrangement direction. 6. A permanent magnet magnet comprising a plurality of permanent magnets arranged side by side with a soft magnetic material interposed therebetween, and facing the same poles of the permanent magnets adjacent to each other via the soft magnetic material. In the circuit, the dimension of the permanent magnet located in the central part of the arrangement direction of the permanent magnet and the soft magnetic material in the arrangement direction is larger than the dimension of the permanent magnet located at the end of the arrangement direction, and The permanent magnet magnetic circuit according to claim 1, wherein the permanent magnet located at the center in the arrangement direction has a characteristic that the coercive force is larger than that of the permanent magnet located at the end in the arrangement direction. 7. A permanent magnet magnet comprising a plurality of permanent magnets arranged side by side with a soft magnetic material interposed therebetween, and facing the same poles of the permanent magnets adjacent to each other via the soft magnetic material. In the circuit, the dimension in the arrangement direction of the soft magnetic material located at the center in the arrangement direction of the permanent magnet and the soft magnetic material is made larger than the dimension in the arrangement direction of the soft magnetic material located at the end in the arrangement direction. A permanent magnet magnetic circuit characterized in that the permanent magnet located at the center in the arrangement direction has a characteristic that the coercive force is larger than that of the permanent magnet located at the end in the arrangement direction. 8. A permanent magnet magnet comprising a plurality of permanent magnets arranged side by side with a soft magnetic material interposed therebetween, and facing the same poles of the permanent magnets adjacent to each other via the soft magnetic material. In the circuit, the dimension in the arrangement direction of the permanent magnets located at the central part in the arrangement direction of the permanent magnets and the soft magnetic material is made larger than the dimension in the arrangement direction of the permanent magnets located at the ends in the arrangement direction. The size of the soft magnetic material located at the center in the direction of alignment is larger than the size of the soft magnetic material located at the end in the direction of alignment, and the permanent magnet located at the center of the direction of alignment. Has a characteristic that the coercive force is larger than that of the permanent magnet located at the end in the arrangement direction. 9. The permanent magnet and the soft magnetic material are formed in an annular body, and the permanent magnet and the soft magnetic material are arranged side by side in the radial direction with the arrangement direction being a radial direction orthogonal to a rotation axis. A superconducting bearing device, wherein the permanent magnet magnetic circuit according to any one of claims 1 to 8 is relatively rotatably disposed on the superconductor. 10. The permanent magnet and the soft magnetic material are formed in an annular body, and the permanent magnet and the soft magnetic material are arranged in a layered manner in the axial direction with the arrangement direction being the axial direction along the rotation axis. A superconducting bearing device, wherein the permanent magnet magnetic circuit according to any one of claims 1 to 8 is relatively rotatably disposed on the superconductor.