JPH0347379A - Vibration controller - Google Patents

Abstract

PURPOSE:To control all direction type vibration by arranging the N and S poles of a magnet to the surface of one part between two members making relative displacement in a shape adjacent to each other, and providing a conductor crossing magnetic force lines from the magnet and moving to the other part. CONSTITUTION:The N pole 9a and S pole 9b of a magnet 9 are arranged to one part 8 making relative displacement by vibration of a construction 6 in a shape adjacent to each other, and a conductor 13 which moves crossing magnetic force lines 12 from the magnets 9... is placed to the other part 11 to form a vibration controller. After that, when vibration occurs in the construction 6, displacement occurs between the construction 6 and a foundation concrete layer 10, and relative displacement of the conductor 13 is made against the magnet 9. When the conductor 13 crosses the magnetic force lines 12 of the magnet 9, overcurrent controlling the variations in the magnetic force lines 12 occurs, and the relative displacement between the conductor 13 and magnet 9 is controlled. Accordingly, effective vibration control can be made against all direction.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a vibration suppression device for structures, and in particular, to effectively damp vibrations in structures caused by external forces such as earthquakes and wind. This invention relates to a suppression device.

"Prior Art" Examples of vibration suppressing devices conventionally used to damp the shaking of structures include oil dampers, steel dampers, and viscous dampers. However, in any of these vibration suppression devices, the damping force is not proportional to the vibration speed, and it is difficult to adjust the damping force, so detailed settings that match the vibration characteristics of the structure are required. In addition, there were problems in that damping force control could not be performed in accordance with disturbances. For this reason,
There is a so-called magnetic damper that uses magnetic force to attenuate the shaking of a structure.As shown in Figure 10, this magnetic damper has a zero-shaped yoke (
N-pole and S-pole magnetic poles 2.
3 are arranged facing each other, and a conductor 4 is arranged to cross between these magnetic poles 2 and 3 with a slight distance between them.

This means, for example, that the yoke 1 is fixed on the ground and the conductor 4
Setting is performed by fixing the yoke to a structure, and when an external force is applied to the structure to generate vibration, the yoke 1 and the conductor 4 move relative to each other, and the lines of magnetic force shown by arrows in the figure and the conductor 4 An electromagnetic induction force is generated between the two, which exerts a damping force proportional to the speed of this relative movement, thereby suppressing the vibration of the structure.

"Problems to be Solved by the Invention" According to the magnetic damper having the above configuration, problems that have occurred with conventional oil dampers, etc., can be solved, namely, damping due to changes in damping force due to external factors such as temperature conditions and vibration conditions. Although we have solved the problems such as the difficulty in adjusting the force and the difficulty in making detailed settings that match the vibration characteristics of the structure, the following new problems have arisen.

In other words, the yoke 1 for creating a magnetic field acting on the conductor 4 is continuous in the vertical direction at its base end, and restricts the movement of the conductor 4 in the direction toward this base end, suppressing vibration. The problem is that the direction is limited. Therefore, a problem arises in that it is difficult to apply this method to vibration damping of a structure that moves in two directions within the plane.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a so-called omnidirectional in-plane vibration suppressing device in which the vibration control direction is not restricted while making full use of the characteristics of the magnetic damper itself.

"Means for Solving the Problems" The vibration suppressing device for a structure of the present invention is provided between two members that move relative to each other as the structure vibrates, and the N and S poles of a magnet are provided on the surface of one part. The magnetic poles are arranged adjacent to each other, and the other portion is provided with a conductor that can be moved across the lines of magnetic force from the magnet.

"Operation" The structure vibration suppressing device of the present invention is characterized in that when a conductor moves perpendicularly to the magnetic field in the magnetic field generated between the S and N poles of the magnet, eddy currents generated in the conductor are generated in the magnetic field. It exerts damping force by interacting with

This damping force occurs in proportion to the relative velocity between the magnetic field and the conductor, that is, the relative velocity between the magnet installed on one part and the conductor installed on the other, so it is The larger the vibration, the greater the damping force exerted.

"Example" Hereinafter, an example of the vibration suppressing device for a structure according to the present invention will be described with reference to the drawings.

1 and 3 are diagrams showing an embodiment of the vibration suppressing device of the present invention, and in the figures, reference numeral 5 is provided between two members that move relative to each other as the structure 6 vibrates. It is a vibration suppression device. This vibration suppressing device t5 has one part 8,
N pole 9 of magnet 9,...! and S poles 9b are arranged adjacent to each other, and the magnets 9,...
- a conductor 13 moved across the magnetic field lines 12 from
It is roughly constructed by arranging.

One portion 8 is, for example, on a concrete foundation 10 facing the lower surface of the structure 6, and a plurality of magnets 9 are arranged on this concrete foundation 10. These magnets 9,
... is the N pole 9! of the adjacent magnet, as shown in Figure 2.
and S poles 9b are arranged on the substrate 14 in an alternating arrangement.

A support plate 2o is integrally provided on the lower surface of the base 14, and the support plate 20 is connected to the bolt 21. ...and fix it to the foundation laying concrete 10. At this time, all magnets 9
, . . . are set so that their surfaces are flush with each other.

The other part 11 is the lower surface of the structure 6 facing the foundation concrete 10, and a jig 15 is attached to the lower surface of the structure 6.
A conductor 13 is provided so as to be parallel to the surface of the magnet.

This vibration suppressing device 5, as shown in FIG.
The structure 6 is constructed on a laminated rubber 16 fixed on a foundation concrete 10 to provide a seismic isolation structure. It is configured to be provided between the structure 6 and the foundation concrete 10 in parallel with the laminated rubber 16.

-Next, the operation of the vibration suppressing device 5 of this embodiment configured as described above will be explained.

When vibration occurs in the structure 6 due to an earthquake or wind, displacement occurs between the structure 6 and the concrete foundation 10, and along with this, the magnets 9 installed on the concrete foundation 1, 10... The conductor 13 installed on the lower surface of the structure 6 is moved relative to the .

Due to such relative movement between the conductor 13 and the magnets 9, . . . , the conductor 13 is moved to cross the magnetic lines of force 12 between the magnets 9, . This conductor 13 is moved
The density of the lines of magnetic force 12 changes in each of the front and rear portions toward the magnets 9, . . . in the direction of movement. And magnetic field lines 12 in the front part and the rear part
Since the changes are opposite, eddy currents are generated that suppress the changes in the magnetic lines of force 12, and a force is generated between the conductor 13 and the magnets 9, . . . that suppresses their relative movement. This force acts on the structure 6 as a force to damp the vibration, and the vibration of the structure 6 is suppressed.

In such a vibration suppressing effect, the damping force generated between the magnets 9, . . . and the conductor 13 is obtained in proportion to the rate of change of the magnetic lines of force 12. A damping force is obtained that is proportional to the strength of and the speed of both.

Therefore, when the magnetic force of the magnets 9, . . . The damping force is adjusted and a good vibration suppression effect is obtained. Further, since the magnets 9, . . . and the conductor 13 are always kept in a non-contact state, there is no change over time such as wear, and durability and reliability are improved.

Hereinafter, an experiment conducted to confirm the effect of the vibration suppressing device for a structure according to the present invention and its results will be described.

First, the arrangement of the magnets used in this experiment is the same as that shown in FIG. 2 above. These magnets 9, . . . are rare earth magnets (residual magnetic flux density: 1 tlQG, maximum energy product: 33.5 KG·0). Normally, a magnetic damper (vibration suppressing device) has magnets facing each other to create a parallel magnetic field, but here, the magnets 9,... are arranged so that the north poles 9a and south poles 9b alternate, and the conductor 13 It is designed to be able to freely move within the plane relative to the magnets 9, . In this case, the lines of magnetic force 12 draw an arch with the north pole 91 and the south pole 9b as the end points.

Next, the results of experiments conducted on the characteristics of the rare earth magnets 9, . . . will be explained.

When measuring the magnetic field, the distance between the magnets should be set at 20°30°.
．． The magnetic flux density in the vertical direction was measured with a setting of 40 mm. As a result, the following vibration experiment was conducted for 40rrrm, which showed the largest average magnetic flux density.

When measuring the amount of attenuation of this magnetic damper (vibration suppression device), the vibration suppression device was set as follows. First, the vibration suppression device 5 was attached to a single-layer steel frame, and a shaking table sweep test and a free vibration test were conducted. The damping constant was calculated based on the transfer function of the steel frame obtained from the sweep test and the response waveform from the free vibration test. A copper plate (0.17XIO-'Ωm) was used as the conductor, and the parameters were the steel plate thickness, copper plate shape, and clearance (distance from the copper plate neutral axis to the magnet surface).

As a result of conducting experiments using this experimental apparatus, the experimental results shown in FIGS. 4 to 8 were obtained.

Figure 4 shows an example of the acceleration transfer function of a steel frame (the horizontal axis is the frequency, the vertical axis is the response magnification), Figure 5 shows the damping coefficient calculated from the damping constant, and Figure 6 shows the shape of the copper plate. A comparison diagram of damping coefficients due to differences in (steel plate thickness is constant at 31III) is shown with copper plate area plotted on the horizontal axis and damping coefficient plotted on the vertical axis. From these results, it can be seen that the damping coefficient is strongly influenced by the steel plate thickness and clearance, but within the scope of this experiment, there is almost no difference due to the shape of the copper plate.

Generally, a magnetic damper (vibration suppressor) in a parallel magnetic field
The damping coefficient calculation formula for is derived from the following formula.

B"・A-1C++ C~・
・ ・■ (B: magnetic flux density, A: magnet area, L: conductor thickness, ρ: conductor resistivity, Co: dimensionless quantity determined by the shape of the magnet and conductor) However, in the case of this damper, the magnetic field is Therefore, the above formula cannot be applied as is.

Under this arcuate magnetic field, the magnetic flux density B(T) depends on the clearance rcm+n). Therefore, the following relational expression was obtained by regressing the measured magnetic field values.

B = Bo/(r Bo=0.55 −
... Integrate the ■■ formula to find the average magnetic flux density in the copper plate,
By substituting into the equation, the following damping coefficient calculation formula is obtained.

8B o” (r -y”pi”7T”7T)) A C
0C-.・■ t Co was determined by regression of the ratio of the experimental value and the value according to the formula (■). However, unlike the case of a parallel magnetic field, Co showed a somewhat specific value depending on the copper plate thickness.

Co=1.3(t-3), Co-1,1(+-6m)
In the case of L/2r<<1, the equation (2) can be approximated by an equation in which B in the 0 equation is replaced by the 0 equation, as shown in the following equation.

BO2・　A　-1・　c.

C-・■ P+r Figure 7 shows the calculated value and experimental value using formula ■, with the horizontal axis representing the damping coefficient (calculated value) and the vertical axis representing the damping coefficient (experimental value). Here, the calculated value according to formula (2) and the experimental value (copper plate thickness 3 mm) are shown, with the horizontal axis representing the clearance and the vertical axis representing the damping coefficient.

The experimental values and calculated values correspond relatively well, and when designing a magnetic damper with an arch-shaped magnetic field on the scale used in this experiment, it can be said that formula (1) or (2) is sufficient. However, it is necessary to further study the relationship between copper plate thickness and Co.

A vibration suppressing device having such characteristics can suppress vibrations of a structure by acting as follows.

When vibration occurs in the structure 6 due to an earthquake or wind, the two members provided with the magnet 9 and the conductor 13 move relative to each other due to the vibration of the structure 6, and such relative movement between the conductor and the magnet occurs. As a result, the conductor is moved to cross the magnetic lines of force 12 between the magnets, and the conductor 1 of the lines of magnetic force 12
3 is moved, and the density of the lines of magnetic force 12 changes on the surface facing the magnet 9 in the direction of movement of this conductor. Since the changes in the magnetic lines of force in the front and rear parts are opposite, eddy currents are generated in each part that suppresses the changes in the lines of magnetic force 12, and the relative movement between the conductor 13 and the magnet 9 is suppressed. A force is generated, and this force acts on the structure as a force that dampens the vibration, thereby suppressing the vibration of the structure.

In such a vibration suppressing effect, the damping force generated between the magnet and the conductor is obtained in proportion to the rate of change of the lines of magnetic force.In other words, it is proportional to the strength of the magnetic force of the magnet and the speed of both. Since a damping force is obtained, the most suitable damping force control can be performed against disturbances acting on the structure.

According to the vibration suppressing device of this embodiment, the conductor 13 can move freely in the plane on the magnet 9, so it is effective against any in-plane disturbance that is applied to the structure 6. This provides an excellent effect of suppressing vibrations.

Further, since the magnet 9 and the conductor 13 are always kept in a non-contact state, there is no change over time such as wear, and durability and reliability are improved.

Next, other embodiments of the vibration suppressing device for a structure according to the present invention will be described with reference to the drawings. In this embodiment, the vibration suppressing device 5 itself has the same structure as that of the previous embodiment, but a laminated rubber layer is attached to both ends of the vibration suppressing device 5.
This embodiment differs from the previous embodiment in that air springs 17 and 17 are used instead of springs 6 and 6.

This embodiment can also provide the same effects as the embodiments described above.

Note that the vibration suppressing device for a structure according to the present invention is not limited to the above-mentioned embodiments, and other modifications are also possible.

For example, instead of the magnet, an electromagnet may be used. At this time, by combining a sensor that detects the magnitude of the vibration of the structure 6 and a computer that controls the current supplied to the electromagnet, it becomes possible to adjust the current supplied to the electromagnet according to the magnitude of the vibration. , it is possible to generate a fine damping force depending on the magnitude of vibration, and a more effective vibration suppressing effect can be obtained.

"Effects of the Invention" The vibration suppression device for a structure of the present invention is provided between two members that move relative to each other as the structure vibrates, and the N pole and S pole of the magnet are placed adjacent to each other in one part. Since the structure is such that a conductor is provided at the other portion and is moved across the lines of magnetic force from the magnet, the following excellent effects can be achieved.

Since the conductor can freely move within the plane relative to the magnet, it is possible to effectively suppress vibrations against disturbances in any direction that are applied to the structure.

In addition, the damping force generated between the magnet and the conductor is obtained in proportion to the rate of change of the lines of magnetic force.In other words, the damping force generated between the magnet and the conductor is obtained in proportion to the strength of the magnetic force of the magnet and the speed of both. , it is possible to perform the most suitable damping force control against disturbances acting on the structure.

Further, since the magnet and the conductor are always maintained in a non-contact state, there is no change over time such as wear, and durability and reliability are improved.

[Brief explanation of drawings]

1 to 3 are diagrams showing an embodiment of the vibration suppressing device for a structure according to the present invention, and FIG. 1 is a side view of the device;
Figure 2 is a plan view of the same, Figure 3 is a side view showing an example of the use of the vibration suppression device, Figures 4 to 8 are data diagrams for explaining the damping characteristics, and Figure 9 is a diagram showing the vibration of the present invention. FIG. 10 is a side view showing another usage example of the suppressing device, and is a diagram showing a conventional example of the vibration suppressing device for a structure. l・ ... ... 2, 91 3, 9 b 4, 13 7 ... 9 ... 12 ... Yoke, ... N pole, ... ...S pole, ...conductor, vibration suppressor, magnet, ...magnetic field lines. ■ Fig. 3 Enoki or Nenshi 488- Fig. 5 ※Garden (Hosho paste)

Claims (1)

[Claims] A vibration suppressing device provided between two members that move relative to each other as a structure vibrates, in which the north and south poles of a magnet are arranged adjacent to each other on the surface of one part, and the A vibration suppressing device for a structure, further comprising a conductor that is moved across lines of magnetic force from the magnet.