JPH0274739A - Earthquake-proof/vibration-proof method - Google Patents

Abstract

PURPOSE:To obtain a low and effective earthquake-proof/vibration-proof device by installing low laminated rubber and a damper wherein a damping plate is set in magnetic fluid and electromagnets are installed therein between an object and a foundation and changing viscosity of the magnetic fluid according to outside vibration. CONSTITUTION:An earthquake-proof and a vibration-proof object 2 is mounted on a foundation 1 by low laminated rubber 3. Next, a damping plate 9 is provided in magnetic fluid 6 put in a vessel 5, between the object 2 and the foundation 1, and a damper 4 providing electromagnets outside the vessel. The damper 4 is connected to a vertical acceleration meter 10 and a horizontal acceleration meter 11 via function converters 12, 13 and an amplifier 14. Viscosity of the magnetic fluid is changed by control for the electromagnets according to outside vibration. Accordingly, a useful and effective earthquake-proof and vibration- proof device without a large space can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a seismic isolation and vibration isolation system against external vibrations such as earthquakes.

[Prior art] Seismic isolation and vibration isolation are performed for buildings, floors within buildings, or mechanical devices on the floors. For example, for buildings, laminated rubber is placed between the foundation and the building, or mechanical devices are In the target products, laminated rubber and spring materials are installed between the floor and the machine foundation.

In addition, the entire floor may be seismically isolated or vibration-proofed by using the building frame as the foundation and supporting the floor with rubber or springs.

In any case, when seismically isolated or vibration-proof objects such as buildings and machinery are subjected to external vibrations such as earthquakes, they are supported using rubber or spring materials to lengthen the vibration period relative to the foundation. In addition, in order to convert vibration energy into heat or other energy and dampen vibration, a hydraulic damper, a magnetic damper, or the like is installed between the seismic isolation or vibration isolation object and the foundation part.

[Problem to be solved by the invention]

For example, if you want to obtain a sufficient seismic isolation effect for a seismically isolated or vibration-proofed object using only laminated rubber supports, you will need very tall laminated rubber, and you will need to secure extra space. It won't happen.

Furthermore, dampers generally provide an integral damping action against external vibrations and are not effective. Furthermore, all conventional systems capture the vibrations in the process of transmitting some of the vibrations of the foundation to the object to be seismically isolated or vibration-proofed, or the vibrations as a result of being transmitted, and act on them to attenuate them.

Therefore, complete damping is theoretically impossible, and damping takes time. Furthermore, if an attempt is made to shorten the vibration damping time, a large amount of energy is temporarily required depending on the mass of the object to be seismically isolated or damped.

Some dampers have a permanent magnet placed in a magnetic fluid and use the viscosity of the magnetic fluid to dampen the movement of the magnet, but the same applies to such dampers.

The purpose of the present invention is to provide a seismic isolation and vibration isolation system that eliminates the disadvantages of the conventional example, uses low laminated rubber to save space for the device, and realizes an optimal damper against external vibrations. be.

[Means to solve the problem]

In order to achieve the above object, the present invention supports a seismic isolation/vibration-proof object with a low-height laminated rubber raised from the foundation, and a magnetic fluid between the foundation and the seismic-isolation/vibration-proof object. The idea is to insert a brake plate into a container filled with magnetic fluid, and attach a damper equipped with an electromagnet to the outside of the container, and change the viscosity of the magnetic fluid by controlling the electromagnet in response to external vibrations.

[Function] According to the present invention, part of the external vibration is absorbed by the low-height laminated rubber, and the remaining vibration is absorbed by the damper having damper characteristics according to the external vibration, thereby effectively achieving seismic isolation. Anti-vibration possible.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is an explanatory diagram showing one embodiment of the seismic isolation and vibration isolation system of the present invention, in which 1 indicates a foundation portion and 2 indicates an object to be seismically isolated and vibration-isolated.

As mentioned earlier, the seismic isolation and vibration isolation objects 2 can be buildings, floors, mechanical devices, etc., while the foundation parts 1 include building foundations or the earth, 91 buildings, building floors, etc. is the target.

The seismic isolation and vibration isolation object 2 is supported by a low-height laminated rubber 3 erected on the foundation part 1.

Furthermore, a damper 4 is provided between the seismic isolation/vibration isolation object 2 and the foundation part 1, and this damper 4 is constructed by filling a container 5 with an opening on the top surface with a magnetic fluid 6, and An electromagnet 7 provided at the bottom is attached to the base part 1 side, and a brake plate 9 inserted into the magnetic fluid 6 in the container 5 via the shaft 8 is provided on the object 2 for seismic isolation and vibration isolation. It is.

FIG. 2 shows the electromagnet 7, in which north and south poles are alternately scattered in a staggered manner. Further, FIG. 3 shows the brake plate 9, which has a large number of holes 9a.

In Fig. 1, lO is a vertical accelerometer, 11 is a horizontal accelerometer, and these are installed on the base part 1, and both jaw velocimeters 10, 11
The outputs of the damper 4 are introduced into the amplifier 14 via function converters 12 and 13, respectively, and the magnetic force of the electromagnet 7 of the damper 4 is controlled by the output of the amplifier 14.

In this way, under normal conditions, the seismically isolated and vibration-proofed object 2 is supported on the base portion 1 by the laminated rubber 3 so as not to move.

When the foundation part 1 vibrates due to an external force such as an earthquake, the laminated rubber 3 acts first to absorb a portion of the vibration.

The equation of motion of the seismically isolated and vibration-proofed object 2 when the seismic isolation and vibration-proofed object 2 is supported by the laminated rubber 3 is the following equation (1).

mχ+αχ+ χ=F−・−・−・(1) However, m:
Mass of seismic isolation and vibration isolation object 2: Spring constant F of laminated rubber 3: External force χ: Displacement α: Damping constant of laminated rubber 3 When only laminated rubber 3 is used, the damping constant α is small and external force F acts. (and f. -1/2πf "Σ;".It vibrates at the resonant frequency of -1/2πf "Σ;".
By setting o to be smaller than external vibrations, external vibrations are prevented from being transmitted as much as possible and a seismic isolation effect is obtained.

The present invention lowers the height of the laminated rubber 3 than before,
Vibrations that cannot be completely absorbed by the laminated rubber 3 are further damped by the damper 4.

That is, the magnetic fluid 6 of the damper 4 has a property that its viscosity changes depending on the strength of the magnetic field passing through it.
By changing this viscosity, the movement of the brake plate 9 is controlled.

The viscosity control of the magnetic fluid 6 of the damper 4 is performed by converting the acceleration and velocity of the external vibration detected by the vertical accelerometer 10 and the horizontal accelerometer 11 into function conversion B12. A voltage is obtained and applied to the electromagnetic cuff to adjust the magnetic field passed through the magnetic fluid 6.

With such a damper 4, the damping constant α in the equation (1) can be optimized according to the acceleration and speed of the vibration, the vibration is quickly damped, and seismic isolation and vibration damping effects can be achieved.

(Effects of the Invention) As described above, the seismic isolation and vibration isolation method of the present invention is supported by low-height laminated rubber, so there is no need to take up a large space between the foundation and the object to be seismically isolated or vibration-isolated. Furthermore, by appropriately controlling the damper in response to external vibrations, effective seismic isolation and vibration damping can be obtained that further improves the seismic isolation and vibration damping effects of this laminated rubber.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing one embodiment of the seismic isolation and vibration damping system of the present invention, FIG. 2 is a plan view of an electromagnet used, and FIG. 3 is a plan view of the same brake plate.

Claims (1)

[Claims] The object to be seismically isolated and vibration-proofed is supported by a low-height laminated rubber raised from the foundation, and a brake plate is inserted between the foundation and the object to be seismically isolated and vibration-proofed in a container filled with magnetic fluid. , and a seismic isolation and vibration isolation system characterized by attaching a damper equipped with an electromagnet to the outside of the container and changing the viscosity of the magnetic fluid by controlling the electromagnet in response to external vibrations.