JPH04362334A - Magnetic damper equipment - Google Patents

Abstract

PURPOSE:To improve the damping force of a magnetic damper equipment and to minimize it. CONSTITUTION:Three permanent magnets 13-15 are formed into a state of contacting each other under the opposite polarity arrangement of each S, N, S pole at an upper side yoke 11, and three permanent magnets 17-19 are formed similarly under the different alloy arrangement of each N, S, N pole opposite to the described each magnet at an lower side yoke 12. A magnetic circuit is constituted by three directional magnetic fields which are shown as an arrow of each permanent magnet from the N pole to the S pole at the opposite side. A conductor plate 20 which is an electrical good conductor such as an aluminum plate, etc., with the fixed depth size (w) and consists of non-magnetic material, is arranged in a non contact state in an empty gap (d) which has high flux density of this magnetic circuit, and a translation type magnetic damper equipment is constituted. And, the width D1 of the permanent magnet positioning at both edges to the moving direction of the conductor plate, is set up narrower than the width D2 of the permanent magnet positioning at the center.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is directed to a magnetic damper device for damping vibrations of various devices and applying load to motion, and in particular improves the braking force for such damping, etc., and also reduces the size of the device. The present invention relates to a magnetic damper device according to the present invention.

0002

[Prior Art] Regarding magnetic damper devices for damping the vibrations of various devices and applying loads to their movements, the theoretical basis is given in literature such as "Proceedings of the Japan Society of Mechanical Engineers No. 890-26". ing. Figure 5(A),
(B) shows a basic model of the conventional translation type magnetic damper device. The magnetic damper device in the figure has yokes 1 and 2 connected at one end in a U-shape and the other end facing each other vertically, and is arranged on the vertically opposing surfaces of each yoke 1 and 2, with their N and S poles connected to each other. Permanent magnets 3 facing each other
.

In the above configuration, when the conductor plate 5 moves relatively in the direction of the arrow at a predetermined speed v, the magnetic flux within the gap d is cut, so that an electromotive force E is generated in the conductor plate 5 due to the principle of electromagnetic induction. Eddy current flows as shown by the chain line in FIG. 5(B). Due to the action of this eddy current and the magnetic field generated between the gap d by the permanent magnets 3 and 4, a braking force is generated in the conductor plate 5 in the direction opposite to the moving direction of the conductor plate 5.

This braking force is generated by the conductor plate 5 or the yoke 1.
, apply a load to the vibration damping and movement of various devices and structures (not shown) connected to the second side, and ensure that the damping force is extremely accurately proportional to the speed of movement, that it acts without contact and is stable, and that the temperature Since it has the advantage that there is little change in the position, it is used, for example, in high-precision positioning of a table device as shown in Japanese Patent Application Laid-Open No. 61-131841, and can be applied to various other uses.

[0005]

[Problems to be Solved by the Invention] However, the conventional magnetic damper device generates braking force by relative movement of the conductor plate 5 only in a magnetic field in one direction from the N pole to the S pole. There were practical problems to be mentioned. That is, first of all, the eddy current that is effectively used to generate braking force is only within the gap d, and the eddy current that flows elsewhere is not effectively used to generate braking force, and as a result, This had the disadvantage of lower efficiency, requiring more powerful magnets to generate sufficient braking force. In addition, in order to cause a sufficient eddy current to flow through the conductor plate 5, the conductor must be made sufficiently larger than the high magnetic flux density region.
The above-mentioned literature states that 3 times or more is preferable. Therefore, the conductor plate 5 becomes significantly large, resulting in an increase in the size of the entire magnetic damper device.

In order to solve the above problem, the present applicant previously proposed a magnetic damper device as shown in FIG. 6 in Japanese Patent Application No. 3-33357. That is, three permanent magnets 7, 8, 9 are arranged on the same yoke surface 6, and the magnetic poles of the surfaces of the permanent magnets 7, 8, 9 facing the conductive plate 10 are made to be different from each other. Specifically, the surfaces of the permanent magnets 7 and 9 at both ends are the north pole, and that of the central permanent magnet 8 is the south pole.

[0007] With this configuration, the conductor plate 10
When it moves in the direction of the arrow at a predetermined speed v as shown in FIG. A current is generated. This eddy current is composed of a first eddy current A that is centered around the side adjacent to the permanent magnets 7, 8, and 9 on the conductor plate 10, and a first eddy current A that revolves around the side adjacent to the permanent magnets 7, 8, and 9 on the conductor plate 10, and a first eddy current A that revolves around the side adjacent to the permanent magnets 7, 8, and 9 on the conductor plate 10, and a first eddy current A that revolves around the side adjacent to the permanent magnets 7, 8, and There are two types of second eddy currents B circulating around it, and the amount of the first eddy current A shown by the solid line is sufficiently larger than the second eddy current B shown by the broken line.

[0008] However, although the magnetic damper device according to the above-mentioned proposal can achieve a remarkable effect compared to the conventional magnetic damper device, it has been found that it has the following new problem. That is, the braking force acting on the conductor plate 10 is generated when an eddy current flows within a high magnetic flux density region, so the second eddy current B, which flows in a large amount outside the region, has a large loss and is generated. Eddy currents are not effectively used to generate braking force. Further, as shown in the figure, the second eddy current B takes a path that largely protrudes outward from the high magnetic flux density region, so that the conductor plate 10
The size and shape of the device must be determined, which can become a bottleneck in miniaturization. The present invention has been made in view of the above-mentioned background, and an object of the present invention is to provide a magnetic damper device that has a stronger braking force while reducing the overall size of the device.

[0009]

[Means for Solving the Problems] In order to achieve the above object, a magnetic damper device according to the present invention includes a magnetic circuit constituted by placing a magnet on one or both opposing surfaces of a yoke, and a magnetic In a magnetic damper device comprising a conductor plate made of a good electrical conductor disposed in a non-contact manner in an air gap having a high magnetic flux density in a circuit, there are three or more magnetic poles of the magnets disposed on the same yoke surface, and Among the plurality of magnets, the width of the magnet located on at least one end side in the direction of relative movement of the conductive plate is narrower than that of other adjacent magnets.

0010

[Function] In the magnetic damper device configured as described above, there are multiple directions of the magnetic field in the air gap with high magnetic flux density, and when the conductor plate moves relative to each other, the adjacent directions are opposite to each other depending on the number of poles of the magnet. Since an electromotive force of can. Moreover, most of the eddy currents generated in the high magnetic flux density regions formed by the permanent magnets located at both ends of the moving direction form loops with the high magnetic flux density regions formed by the adjacent wide permanent magnets. The amount of eddy current flowing around the outer sides of the high magnetic flux density regions at both ends becomes smaller. Therefore, the amount of eddy current in the high magnetic flux density region that effectively contributes to the generation of braking force is increased, and the braking force is improved.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. FIGS. 1 and 2 show a first embodiment in which a three-pole pole arrangement, which is the basic structure of the present invention, is applied to a translational magnetic damper device that linearly moves a conductor plate.

In FIG. 1, three permanent magnets are arranged facing each other on the opposing surfaces of the upper and lower yokes 11 and 12, each of which has one end connected in a U-shape. Specifically, the upper yoke 11 is formed with three permanent magnets 13, 14, and 15 in a different polar arrangement of S, N, and S poles in contact with each other, and the lower yoke 12 is formed with three permanent magnets 13, 14, and 15 in contact with each other. Opposed to each of the magnets are three permanent magnets 17 and 18 arranged in different polarities of N, S, and N poles.
, 19 are formed in the same manner, and a magnetic circuit is constructed by magnetic fields in three directions from the north pole to the south pole of each permanent magnet on the opposing surface, as indicated by the arrows in the figure. A gap d having a high magnetic flux density in this magnetic circuit has a predetermined depth w in a non-contact state.
A conductive plate 20 made of a non-magnetic electrically conductive material such as an aluminum plate is disposed to constitute a translational magnetic damper device.

In the present invention, as shown in FIG. 2, the width D1 of the permanent magnets 13, 15, 17, 19 located at both ends in the direction of movement of the conductor plate 20 is determined by the width D1 of the permanent magnet 14 located at the center. , 18 is set narrower than the width D2 of .

In the above configuration, when the conductor plate 20 moves relatively in the direction of the arrow at a predetermined speed v as shown in FIG.
In order to cut the magnetic flux in the air gap d, electromotive forces E1, E2, and E3 are induced to the conductor plate 20 according to Fleming's right-hand rule, and as a result, on the conductor plate 20, the magnetic damper device according to the previously proposed Similarly, the first and second eddy currents A and B
Two types of eddy currents flow.

This eddy current generates a braking force on the conductor plate 20 in the direction opposite to the moving direction (arrow direction) of the conductor plate 20 due to the action of the magnetic field, and the conductor plate 20 or the yoke 1
Loads are applied to vibration damping and motion of various devices (not shown) connected to the 1 and 12 sides. Based on the same principle as the magnetic damper device previously proposed by the applicant mentioned above, the two first eddy currents A shown by the solid lines in the center mainly flow, and the second eddy currents A flowing outward, shown by the dashed lines on the left and right. The eddy current B becomes more difficult to flow than in the center.

Moreover, in the present invention, the central permanent magnet 14
, 18 is made wider, the first eddy current A flows even larger than the one proposed above, and the second eddy current B becomes smaller. This is due to the following reasons.

Now, for convenience, three sets of permanent magnets 13, 17, 1
When the first, second, and third high magnetic flux density regions 21, 22, and 23 on the conductor plate 20 formed by 4 and 18, and 15 and 19 are shown by broken lines, the sides 21a and 21a located on the upper side in the figure,
Positive, negative, and positive potentials are generated at 22a and 23a, respectively. Although not shown, a potential opposite to the above is generated on the lower side.

Therefore, the first eddy current A flowing out from side 21a flows into the left half of side 22a, and also flows into the left half of side 23a.
The first eddy current A flowing out from the right half of the side 22a flows into the right half of the side 22a. In other words, the permanent magnets 13, 1 at both ends
Most of the eddy currents flowing out or flowing from the first and third high magnetic flux density regions 21 and 23 formed by 5, 17, and 19 are generated between the adjacent central second high magnetic flux density region 22. It will exist. As a result, the first eddy current that can effectively contribute to the generation of braking force increases, and the amount of the second eddy current B, which has a large loss, decreases. Furthermore, as described above, since the amount of the second eddy current B becomes smaller, the amount of the second eddy current B that protrudes outward also becomes smaller, and as a result, the length of the conductor 20 in the moving direction can also be reduced, and as a result, the conductor plate The area of the device can be reduced, and the entire device can be made more compact.

Next, in order to confirm the effects of the present invention, the braking force was measured using the ratio of the widths D1 and D2 of each permanent magnet in a magnetic damper device having three magnetic poles shown in FIG. 2 as a parameter, and the results were is shown in Figure 3. As shown in Figure (A), in this experiment, the widths of all three magnetic poles were equal (D
1=D2) (comparative example) and one in which the width of the magnetic poles located on both sides is half that of the center (2·D1=D2) (product of the present invention). In addition, in these two magnetic damper devices, the total width of the permanent magnet, which is the width of the three magnetic poles each has, is made equal.

As is clear from the same figure (B), D1=D
In the magnetic damper device set to 2, the maximum braking amount F generated is 300 (gf), whereas in the magnetic damper device according to the present invention, which is set to 2・D1=D2, the maximum braking amount F generated is 330 (gf).
f), and the braking force increases. Moreover, the magnetic damper device according to the present invention can exert the maximum braking force even when the protrusion amount A of the conductor plate is small. Therefore,
It also has the effect of being able to be made more compact.

FIGS. 4A and 4B show a second embodiment of the present invention. This embodiment differs from the above embodiments in that it is applied to a rotating magnetic damper device.

First, the basic structure of this rotary magnetic damper device will be explained. A pair of upper and lower disk-shaped yokes 32 and 34 are attached to a shaft 30.
A permanent magnet is disposed at a predetermined position on the opposing surface. and,
The magnetic poles of the permanent magnets arranged vertically and oppositely are different from each other. In a conventional general rotary magnetic damper device, the permanent magnets arranged on the same yoke are arranged one by one at a predetermined interval, but in this embodiment, one of the permanent magnets is arranged on one yoke. On the surface, three permanent magnets 56, 57, 5 are arranged at predetermined intervals along the circumferential direction, and a plurality of pairs of different poles are in close contact with each other.
8 is placed. In addition, on the opposing surface of the other yoke, a plurality of pairs of permanent magnets with different polarities, whose magnetic poles are opposite to those of the permanent magnets 56, 57, and 58, are arranged facing each other, and a disc-shaped conductor plate is arranged between them. 40 is provided so as to be rotatable in a non-contact state.

In the present invention, the width of the central permanent magnet 57 is set wider than that of the permanent magnets 56 and 58 at both ends. Therefore, according to the above configuration, each permanent magnet 56,
Between 57 and 58, there is no air gap between the permanent magnets, so the magnetic path is shortened, so the magnetic flux density becomes high, which is effective for the braking force proportional to the square of the magnetic flux density. Also,
When the conductor plate 40 rotates in the direction of arrow A at a predetermined speed v,
In order to cut the magnetic flux of each permanent magnet facing each other with the conductor plate 40 in between, the electromotive force is applied to the conductor plate 4 according to Fleming's right-hand rule.
0, and as a result, a predetermined eddy current flows in each conductor plate 40 in a loop shape.

This eddy current generates a braking force on the conductor plate 40 in the direction opposite to the direction of the arrow A due to the action of the magnetic field, thereby applying a load to the movement of various devices (not shown) connected to the shaft 30 of the conductor plate 40. However, in this embodiment, the first eddy current A shown by the solid line in the center mainly flows based on the same principle as the above-mentioned embodiment, and the second eddy current A flows outward to the left and right of it, shown by the broken lines. The eddy current B at is smaller than that at the center.

[0025] In each of the above-mentioned embodiments, an example was explained in which adjacent permanent magnets are arranged in contact with each other. may be provided. Further, in each of the embodiments described above, permanent magnets were used as the magnets constituting the magnetic circuit, but electromagnets may be used depending on the application, for example, when it is necessary to control the braking force. Alternatively, a magnet may be provided only on one yoke. Further, as the conductor plate 20, although in each of the above embodiments an electrically good conductor made of metal such as an aluminum plate is used, it is also possible to use an electrically good conductor made of a non-metallic material. Further, in each of the embodiments described above, a set of three magnetic poles was used, but the present invention is not limited to this, and it goes without saying that four or more magnetic poles may be combined.

[0026]

Effects of the Invention As described above in detail through each of the embodiments, in the magnetic damper device according to the present invention, there are multiple directions of the magnetic field in the air gap with high magnetic flux density, and when the conductor plate moves relative to each other, Since electromotive force is generated in opposite directions between adjacent magnets depending on the number of poles of the magnet, more eddy current flows in the conductor plate within the high magnetic flux density gap, and the eddy current directed to the outside is reduced accordingly. As a result, the eddy current within the gap can be increased, and the area of the conductor plate can also be reduced. Moreover, among adjacent magnets in the same yoke, the width of the magnetic poles located at both ends in the relative movement direction is narrower than the width of the adjacent magnetic poles, so the eddy current flowing outside of both ends becomes smaller, and the generated eddy current can contribute to the generation of braking force, and the above effects are further improved. Therefore, according to the present invention, the device can be miniaturized and a strong braking force can be ensured.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a first embodiment of a magnetic damper device according to the present invention.

2(A) is a front view showing the apparatus of the first embodiment shown in FIG. 1. FIG. (B) is a plan view thereof.

FIG. 3(A) is a schematic configuration diagram showing an apparatus used in an experiment to demonstrate the effects of the present invention. (B) is a graph showing the experimental results.

FIG. 4(A) is a front view showing a second embodiment of the magnetic damper device according to the present invention. (B) is an explanatory diagram showing how eddy currents are generated when the conductive plate is moved.

FIG. 5(A) is a front view showing a basic model of a conventional translational magnetic damper device. (B) is an explanatory diagram showing how eddy currents are generated when the conductive plate is moved.

FIG. 6 is an explanatory diagram showing how eddy currents are generated when a conductor plate is moved in a magnetic damper device previously proposed by the present applicant.

[Explanation of symbols]

11, 12, 32, 34 Yoke 13, 14, 1
5, 17, 18, 19, 36, 37, 38, 56, 57
, 58 permanent magnet 20, 40 conductor plate

Claims (1)

[Claims] [Claim 1] Consisting of a magnetic circuit formed by placing magnets on one or both of the opposing surfaces of the yoke, and a good electrical conductor placed in a non-contact state in the gap having a high magnetic flux density in this magnetic circuit. In a magnetic damper device comprising a conductor plate, there are three or more magnetic poles of the magnets arranged on the same yoke surface, and at least one end side of the plurality of magnets in the direction of relative movement of the conductor plate. A magnetic damper device characterized in that the width of the magnet located in the relative movement direction is narrower than that of other adjacent magnets.