JP2662618B2 - Dynamic damper - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention suppresses vertical vibrations generated in buildings (buildings, large span roofs, bridges, viaducts, etc.) due to earthquakes, winds, traffic, and the like. The present invention relates to such a vibration suppressing device.

"Conventional technology and its problems" Due to factors such as the development of high-strength materials, advances in machining technology, and the development of structural analysis technology using computers, recent structures have become larger, diversified, and lighter. As it progresses, it is becoming more flexible. And
Such a lightweight and flexible structure tends to have a low natural frequency and a small vibration damping.
Not only in the case of an earthquake, there is a possibility that various unpredictable vibrations may occur due to the effects of wind or traffic or other external forces.

And as a conventional dynamic damper for suppressing this kind of vibration, by combining a mass, a spring and a viscous damper in an observation tower or the like,
There is known one that suppresses horizontal vibration.

However, as a result of observing the degree of shaking when a strong earthquake occurred in many recently built skyscrapers,
The primary natural period of longitudinal vibration due to expansion and contraction of columns of a skyscraper is
About 0.5 seconds in a 50-story steel-frame building, and the secondary natural period is 0.1
Seven seconds, the third natural period is about 0.1 second. The vertical component of the ground motion (especially in the case of an earthquake close to the direct type) has a strong periodic component centering on the order of 0.5 seconds, so in a skyscraper, horizontal motion is amplified. It is often observed that vertical movement is amplified even though there is no such movement.

Therefore, the maximum acceleration on the top floor is often larger in vertical motion than horizontal motion. In a skyscraper, the vertical acceleration during an earthquake is amplified, and the highest floor (40-60 floors) It was found that the vertical vibration of ()) was amplified three to five times as much as the vertical vibration of the basement floor.

In the near future, it is expected that the buildings will be made even higher. However, it will be necessary to develop some kind of device to suppress the vertical vibration generated in these skyscrapers. I have.

The present invention has been made in view of the above problems,
An object of the present invention is to provide a dynamic damper for efficiently damping vertical vibrations generated in a large building such as a skyscraper, a large span roof, a bridge, a viaduct, and the like.

"Means for Solving the Problems" The present invention provides a liquid storage tank provided in a building, a plurality of cylinders having both ends open, and a through hole in the cylinder in the longitudinal direction of the cylinder. By disposing the formed vibrating body, and supporting the vibrating body by springs respectively disposed at both ends of the cylinder, and fixing these cylinders in a state of being submerged in the liquid stored in the liquid storage tank, The above problem has been solved.

[Operation] The natural frequency of the vibrating body (dynamic damper) in the liquid storage tank is made to match the natural frequency of the longitudinal vibration of the building. When the building vibrates in the vertical direction due to an earthquake or wind,
In response to this, the vibrating body provided in the cylinder in the liquid storage tank vibrates in the vertical direction, but the liquid in the storage tank becomes a resistance and gives the vibrating body an appropriate damping property. The liquid in the liquid storage tank oscillates out of phase with the vibration of the building, thereby suppressing vertical vibration of the building. The amount of liquid passing through the vibrating body is changed by changing the cross-sectional area of the through hole of the vibrating body, thereby adjusting the damping of the dynamic damper.

"Example" Hereinafter, a dynamic damper of the present invention will be described with reference to the drawings. 1 to 4 show a first embodiment of the present invention. In the drawings, reference numeral 1 denotes a dynamic damper of the present embodiment.

A plurality of dynamic dampers 1 are provided inside a water storage tank (liquid storage tank) 2 provided on the top floor of a skyscraper (not shown).
The main components are an outer shell cylinder 3 and a columnar vibrator 5 mounted inside the cylinder 3 via an upper spring 4a and a lower spring 4b.

The cylinder 3 has a cylindrical cylinder body 3a with an open upper and lower part, and a rod-shaped support member at the bottom of the cylinder body 3a.
3b, 3b,... And a bottom plate 3c fixed by 3b. Furthermore, on the inner peripheral surface of the cylinder body 3a,
Guide rails 3d are provided at predetermined intervals in the circumferential direction and extend along the longitudinal direction, and are fixed (see FIG. 2). The guide rails 3d, 3d,. 5
The oscillating body 5 is restrained from moving in the circumferential direction by slidably engaging with the groove 5a formed in the longitudinal direction on the outer peripheral surface of the vibrating member. Each guide member 3d is coated with Teflon in order to obtain a rust prevention measure and a sliding effect.

The vibrating body 5 has an outer diameter of the cylinder 1 so as to form a gap of a predetermined size with the inner peripheral surface of the cylinder 1.
Are formed to be slightly smaller than the inner diameter of the vibrator 5, and further, through holes 5b, 5b,. And the vibrating body 5
One end of the above-mentioned spring 4a is fixed to the upper end surface of the cylinder, and the other end of the upper spring 4a is fixed to a fixing plate 6 fixed to the upper end of the cylinder body 3a. Further, one end of a lower spring 4b is fixed to a lower end surface of the vibrating body 5, and the other end of the lower spring 4b is fixed to a tip of a rod-shaped member 7 fixed to an upper portion of the bottom plate 3c. It has a configuration.

The dynamic damper 1 configured as described above has a total weight W (total weight of the vibrating body 5 × the number of dynamic dampers) of 1/300 to 1/300 of the ground portion of the building where the dynamic damper 1 is installed. Water tank 2 so that the weight is about 500
It has been installed inside. In addition, the dynamic damper has been subjected to rust prevention treatment.

Next, the operation of the thus configured dynamic damper of this embodiment will be described.

When a vertical vibration is generated in the building due to an earthquake, wind, or the like, the vibration body 5 provided on the cylinder 3 in the water storage tank 2 vibrates in the vertical direction in resonance with the vibration, but the water in the water storage tank is not vibrated. Is resistance when the vibrating body moves in the vertical direction. Also, a plurality of through holes 5b, 5b,... Having a predetermined diameter are formed in the vibrating body 5, and a part of water passes through the through holes 5b to give damping to the vibrating body. Therefore, the vibrating body 5 in the water storage tank 2 performs vibration out of phase with the vibration of the building, thereby attenuating the vertical vibration of the building.

Here, with reference to FIGS. 4 and 5, the relationship between the vibration frequency and the amplitude of the vibration model when the dynamic damper of this embodiment is used and the vibration model when not using the dynamic damper will be compared. FIG. 4 shows a case where a dynamic damper is used, and FIG. 5 shows a case where it is not used. In FIGS. 4 (b) and 5 (b), reference numeral 10 denotes a building, and 11 denotes a dynamic damper. When the dynamic damper of FIG. 4 (a) is used, the amplitude of the building is reduced to about 1/3 of that when the dynamic damper of FIG. 5 (a) is not used, and the vibration damping effect of the dynamic damper is reduced. You can see that it is being demonstrated.

The amount of water passing through the vibrating body 5 is changed by changing the cross-sectional area and the number of the through holes 5b of the vibrating body 5, or the gap size between the vibrating body 5 and the cylinder 3, thereby changing the dynamic damper. Adjust the decay rate.

Thus, the dynamic damper of this embodiment is
Since a plurality of cylinders 1 are provided inside a water storage tank 2 provided in a skyscraper, and a vibrating body 5 for circulating a predetermined amount of water through a spring is provided inside the cylinder 1. In addition, vertical vibrations generated in a skyscraper can be efficiently attenuated, and comfort and comfort can be secured.

In addition, the longitudinal vibration of a steel-framed building has a very small damping rate due to the high degree of fixation of the lower part (underground part) of the building, and the influence of the secondary members is small, so that the natural period of a large earthquake Does not fluctuate so much, the use of the dynamic damper of the present embodiment makes it possible to efficiently suppress vibration.

Note that other embodiments or technical matters other than those described above will be described below.

(I) In the above embodiment, the dynamic damper of the present invention is applied to a skyscraper. However, the present invention is not limited to this, and can be applied to a large span roof, a bridge, a viaduct, and the like. In this case, a required number of sealed water tanks containing a dynamic damper are installed on a roof, a bridge, or the like.

(Ii) In the above embodiment, the dynamic damper is placed in the water tank. However, the present invention is not limited to the water tank and may be any liquid having a predetermined viscosity.

(Iii) The dynamic damper of the above embodiment uses a cylindrical cylinder and a columnar vibrator. However, the dynamic damper is not limited to such a shape, and may have a polygonal shape such as a square cross section or a hexagon. Good. Further, it is a matter of course that the attenuation rate can be changed by appropriately changing the size and number of the through holes formed in the vibrating body, the spring constant, the viscosity of the liquid in the liquid storage tank, and the like.

(Iv) In the above embodiment, the dynamic
The damper was used as a vibration damper for longitudinal vibration,
By changing the configuration of the spring, it can be used as a horizontal dynamic damper.

[Effects of the Invention] As described above, the dynamic damper of the present invention is provided with a plurality of cylinders having both ends open inside the liquid storage tank and forming a through hole in the cylinder in the longitudinal direction of the cylinder. The vibrating body is arranged, and the vibrating body is supported by springs respectively provided at both ends of the cylinder, and then these cylinders are fixed in a state submerged in the liquid stored in the liquid storage tank. Therefore, when a vertical vibration occurs in a building due to an earthquake, wind, or the like, the liquid serves as a resistance of the vibrating body. The vibrating body generates vibration having a different phase from the vibration cycle of the building, thereby efficiently suppressing vertical vibration of the building.

[Brief description of the drawings]

1 to 4 show an embodiment of the present invention. FIG. 1 is a perspective view of a dynamic damper, FIG. 2 is a cross-sectional plan view of the dynamic damper, and FIG. FIG. 4 (a) is a perspective view of a dynamic damper installed inside the vehicle, FIG. 4 (a) is a diagram showing the relationship between the frequency and amplitude of a building when a dynamic damper is used, and FIG. 4 (b) is a vibration diagram. FIG. 5 (a) is a diagram showing the relationship between the frequency and amplitude of a building when no dynamic damper is used, and FIG. 5 (b) is a vibration model. 1 Dynamic damper 2 Water tank (liquid storage tank) 3 Cylinder 4a Upper spring 4b Lower spring 5 Vibrating body

Claims (1)

(57) [Claims] 1. A plurality of cylinders having both ends open are installed in a liquid storage tank provided in a building, and a vibrating body having a through hole formed in a longitudinal direction of the cylinder is disposed inside the cylinder. A dynamic damper wherein the vibrating body is supported by springs provided at both ends of a cylinder, and the cylinder is fixed in a state of being submerged in the liquid stored in the liquid storage tank.