JPH1144127A - Vibration control device for pole - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a large vibration control effect to external vibration by an earthquake without largely impairing external appearance of a pole by sealing fluid in a ring-shaped vessel, fitting and installing this vessel around the pole, and making a swinging frequency almost coincide with a natural frequency of the pole. SOLUTION: Fluid 2 is sealed in a vessel 3 formed in a ring shape, and this vessel 3 is fitted and installed around a pole 1, and its swinging frequency is made to almost coincide with a natural frequency of the pole 1. When the vessel 3 tries to vibrate according to vibration of the pole 1, since the fluid 2 sealed in the vessel 3 swings in the direction for negating the vibration, the vibration of the pole 1 can be restrained, and plastic deformation and damage of the pole 1 can be prevented. A collision sound or the like is not particularly generated by external vibration such as an earthquake and traffic vibration, and the vibration can be effectively controlled. Since the vessel 3 to constitute a vibration control device is formed in a ring shape and is fitted around the pole 1, external appearance of the pole 1 is not largely impaired.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pole damping device for suppressing the vibration of a pole such as a power distribution pole, a mobile telephone receiving / transmitting pole, and a lighting pole.

[0002]

2. Description of the Related Art Generally, a pole 1 vibrates under an external force such as an earthquake, wind, traffic vibration, or the like, and in some cases, compositional deformation or fatigue failure may occur. Therefore, techniques for suppressing this type of vibration have been conventionally proposed.

[0003] That is, a technique for optimizing the natural frequency of the pole 1 by appropriately designing the weight, shape, and rigidity of the pole 1 and mounting a vibration damping device having a vibration damping effect on the pole 1 to achieve resonance. There is a technique to mitigate the phenomenon. As the former technique, for example, it is conceivable to set the cross-sectional shape (thickness, diameter) of the pole 1 according to the installation location of the pole 1, but the design value of the pole 1 is multiplied for each installation location. Not practical. Therefore,
Generally, the latter technique is often applied.

[0004]

As shown in FIG. 7, as a vibration damping device, a plurality of weights 8 such as metal balls are arranged inside a pole 1 so that the vibration of the pole 1 can be reduced. A device that converts the collision into a collision between the weight bodies 8 and absorbs vibration has been considered. (Japanese Utility Model Laid-Open No. 4-131806).
However, in this configuration, since the weight body 8 collides, there are inconveniences such as a collision sound being generated and the weight body 8 being damaged, and additional measures are required to solve these inconveniences. .

[0005] As shown in FIG. 8, a container 3 in which a fluid 2 such as silicon oil, water, sand, or iron sand is provided inside the pole 1, and the container 3 is connected to the pole 1. One that suppresses the vibration of 1 is also considered. (Japanese Unexamined Utility Model Publication No. Hei 2-6835) In this configuration, viscous damping is added for the main purpose of reducing the vibration caused by Karman vortices generated in strong winds. Therefore, the effect of sufficiently suppressing the vibration of the pole 1 (response in which the primary and secondary vibration modes become excellent large fluctuations) caused by the external vibration having a large amplitude cannot be expected.

In the conventional examples shown in FIGS. 7 and 8, the vibration damping device is incorporated inside the pole 1, and the vibration damping is considered from the beginning. In this case, since the damping device is not visible from the outside, the appearance of the pole 1 is not impaired by incorporating the damping device. However, when installing the damping device on the installed pole 1,
Since the vibration damping device cannot be incorporated in the inside of the pole 1, the vibration damping device has to be mounted in a place that can be seen from the outside, and there is a problem that the appearance of the pole 1 is spoiled.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a large vibration damping effect against external vibrations which cannot be sufficiently suppressed by the prior art, particularly, external vibrations caused by earthquakes. Another object of the present invention is to provide a pole damping device that can be obtained and that is externally attached to an installed pole and does not significantly impair the appearance of the pole.

[0008]

In order to achieve the above object, according to the first aspect of the present invention, a fluid 2 is sealed in a container 3,
The container 3 is attached to the pole 1, and in a vibration damping device for the pole 1 having a swing frequency substantially equal to the natural frequency of the pole 1, the container 3 is formed in a ring shape. It is characterized by being fitted to the outside.

In such a vibration damping device for the pole 1, when the container 3 tries to vibrate due to the vibration of the pole 1, the container 3
The vibration of the pole 1 can be suppressed by the fluid 2 sealed in the inside swinging in a direction to cancel the vibration. Here, the oscillating frequency is a frequency at which the center of gravity of the fluid 2 moves when the fluid 2 in the container 3 oscillates, and can be theoretically derived by the Hausner's theory. When the oscillation frequency is made to match the natural frequency of the pole 1, the natural vibration component of the pole 1 is reduced, so that the vibration of the pole 1 is greatly reduced. Can be prevented.

Further, since the container 3 constituting the vibration damping device is formed in a ring shape and is fitted on the pole 1, the appearance of the pole 1 is not significantly impaired.

The invention according to claim 2 is characterized in that, in the invention according to claim 1, the container 3 is vertically divided from substantially the center.

In such a vibration damping device for the pole 1, the ring-shaped container 3 is vertically divided substantially from the center and is formed in a half-ring shape.
Can be easily fitted from both sides. Even when the vibration damping device is mounted on the installed pole 1, it can be easily mounted.

A third aspect of the present invention is characterized in that, in the first or second aspect of the present invention, a plurality of containers 3 having substantially the same shape are stacked.

In such a vibration damping device for the pole 1, since a plurality of containers 3 having substantially the same shape are stacked, the vibration damping performance is improved.

The invention according to claim 4 is characterized in that, in the invention according to claim 3, the amount of the fluid 2 sealed in each container 3 is changed.

In such a vibration damping device for the pole 1, since the amount of the fluid 2 sealed in the substantially same-shaped containers 3 that are externally fitted to and stacked on the pole 1 is different from each other, each of the containers 3 is The oscillation frequencies are different, and the oscillation characteristics of the vibration damping device obtained by synthesizing the oscillation characteristics of these containers 3 show characteristics having a plurality of oscillation frequency peaks. Therefore, since there is a range in the peak oscillation frequency, even if the oscillation frequency of the pole 1 changes, the damping performance does not decrease.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a pole damping device according to the present invention will be described below with reference to FIGS.

FIGS. 1A and 1B show a pole damping device according to an embodiment of the present invention. FIG. 1A is a front view of the pole, and FIG. 1B is a perspective view of the pole damping device. Further, in (a), A indicates a state where the pole does not vibrate, and B indicates a maximum vibration state when the pole vibrates.

As shown in FIG. 1, in this pole damping device, the upper end of a columnar road lighting pole 1 erected on the ground 5 is bent, and a lamp 7 is provided at the tip. .
A ring-shaped container 3 is fitted to the center of the pole 1.

The pole 1 is formed from a steel pipe and has a taper that becomes thinner toward the upper side. The container 3 is formed by providing an inner cylinder 3a and an outer cylinder 3b coaxially, and sealing a ring-shaped space between the inner cylinder 3a and the outer cylinder 3b with a donut plate-shaped bottom plate 3d and a lid plate 3c from above and below. ing. A fluid 2 such as silicone oil is sealed in the container 3. The inner diameter of the container 3 is formed substantially the same as the outer diameter of the central portion of the pole 1.

In such a vibration damping device for the pole 1, the lamp 7 at the tip of the pole 1 is removed, and the container 3 is inserted from the thin tip of the pole 1.
To the outside. Then, it is fixed at the center of the pole 1 having an outer diameter substantially matching the inner diameter of the container 3.

In such a vibration damping device for the pole 1, when the container 3 tries to vibrate due to the vibration of the pole 1, the container 3
The vibration of the pole 1 can be suppressed by the fluid 2 sealed in the inside swinging in a direction to cancel the vibration. When the oscillation frequency of the damping device of the pole 1 is made to coincide with the natural frequency of the pole 1, the natural vibration component of the pole 1 is reduced, so that the vibration of the pole 1 is greatly reduced. In addition, plastic deformation and breakage of the pole 1 can be prevented.

Further, since the container 3 constituting the vibration damping device is formed in a ring shape and is externally fitted to the pole 1, the appearance of the pole 1 is not significantly impaired.

Further, since the damping device can be attached to the already installed pole 1, there is no need to replace the pole 1 with the damping device, and the construction is simple.

A specific example of the vibration control device of the pole 1 can be exemplified as follows. Pole 1 taper: 1/1
00, height of pole 1: 12 m, mass of lamp 7: 22.
5 kg, inner diameter of container 3: 130 mm, outer diameter of container 3: 2
20 mm, kinematic viscosity of fluid 2 500 cs, liquid level 2 of fluid 2
a Height: 100mm

Under the above conditions, the primary natural frequency of the pole 1 is about 0.9 Hz, and the secondary natural frequency is about 2.7 H
z, the third-order natural frequency is about 7.0 Hz.

FIG. 2 is a graph showing the damping performance of the above-described pole damping device.

FIG. 2 shows a reaction force characteristic curve when the pole vibration damping device of the above example is swept in a horizontal direction at a predetermined acceleration level.

As shown in FIG. 2, the peak of the reaction force is 1.6.
Hz, and the frequency of this peak is the oscillation frequency of the container.

FIG. 3 is a graph showing the change over time of the vibration acceleration in the above-described pole vibration damping device.
(A) shows the case where the damping device is not attached to the pole, and (b) shows the case where the damping device is attached to the pole.

In FIG. 3, the vibration of the pole is
This is caused by the vertical vibration of the vicinity of the base of the pole on the ground surface due to an external force that is impressive when a truck or the like passes through the joint on the pier. In this traffic vibration,
The secondary natural frequency of the pole is about 2.7 Hz. (A)
As shown in (1), when the damping device is not attached to the pole, the pole vibrates greatly due to traffic vibration.

In the case where the pole damping device of the specific example shown in FIG.
In order to swing at a swing frequency of 6 Hz and cancel the pole vibration, the pole vibration is attenuated.

FIG. 4 is an exploded perspective view showing a different pole damping device according to the embodiment of the present invention.

In FIG. 4, the vibration damping device for the pole 1 includes a fluid such as silicon oil in a pair of semi-ring-shaped containers 3 formed by vertically dividing a ring-shaped container 3 from substantially the center. 2 is enclosed. Each of the pair of containers 3 has a fixing piece 4 whose both end surfaces extend outwardly, and the fixing piece 4 is provided with a bolt hole for fixing a bolt.

In such a vibration damping device for the pole 1, the pair of containers 3, 3 are externally fitted to the center of the pole 1 so as to be sandwiched from both sides, and the corresponding end surfaces and the fixing pieces 4 are brought into contact with each other to fix the bolt. By doing so, the ring-shaped container 3 is formed and fixed. The inner diameter of the ring-shaped container 3 is formed to be substantially the same as the outer diameter of the central portion of the pole 1 so that the container 3 does not slip below the pole 1 and is fixed at the central portion of the pole 1. The performance of the vibration damping device of the pole 1 is the same as the result shown in FIG.

In such a vibration damping device for the pole 1, the ring-shaped container 3 is vertically divided substantially from the center, and is constituted by a pair of half-ring-shaped containers 3; The containers 3, 3 can be easily fitted from both sides of the pole 1. Even when the damping device is mounted on the installed pole 1, there is no need to replace the pole with the damping device, and the pole 1 can be easily mounted.

5A and 5B show a pole damping device different from the above-mentioned embodiment of the present invention, wherein FIG. 5A is a perspective view, and FIG. 5B is a temporal change in vibration acceleration of a pole provided with this damping device. FIG.

In FIG. 5, the vibration damping device of this pole
A plurality of ring-shaped containers 3 having substantially the same shape are stacked.
The container 3 has substantially the same shape as the container 3 shown in FIG.
It is fitted to the center of the pole from the tip of the pole.

In such a vibration damping device for a pole, since a plurality of containers 3 having substantially the same shape are externally fitted to the pole in a stacked state, the reaction force against the vibration of the pole becomes large, and as shown in FIG. The damping performance is improved as compared with the pole damping device including the single container 3.

FIGS. 6A and 6B show a damping device for a pole different from the above-mentioned embodiment of the present invention. FIG. 6A is a perspective view, and FIG. 6B shows a temporal change of the vibration acceleration of a pole provided with the damping device. FIG.

In FIG. 6, as shown in FIG. 5, a plurality of containers 3 having substantially the same shape are stacked and externally fitted on a pole.
Is changed in the amount of the fluid 2 to be sealed.

More specifically, two ring-shaped containers 3 used in the vibration damping device of the pole shown in FIG. 1 are used, and the liquid level 2a of the fluid 2 such as silicon oil sealed in each container 3 is used.
The heights are set to H1 = 80 mm and H2 = 110 mm, respectively. In this case, the oscillation frequency of each container 3 is substantially proportional to the height of the liquid surface 2a of the fluid 2 sealed in the container 3, and
Is about 1, 4 Hz at a height of 80 mm,
At 0 mm, the frequency is about 1.7 Hz. When the two containers 3 having different swing frequencies are stacked and externally fitted to a pole, the vibration damping device of the pole exhibits a reaction force characteristic obtained by combining the reaction force characteristics of the containers 3 with each other. It has two peaks at 0.7 Hz. Therefore, the oscillation frequency is 1.4H
It has a width of z to 1.7 Hz.

In such a pole damper, since the amount of the fluid 2 sealed in the containers 3 of substantially the same shape which are externally fitted to the poles and stacked is different, the oscillation frequency of each container 3 is different. However, the oscillation characteristics of the vibration damping device obtained by combining the oscillation characteristics of these containers 3 have a robustness in which the oscillation frequency has a width. Therefore, even if the oscillation frequency of the pole 1 changes within the range of the oscillation frequency, the damping performance does not decrease.

In FIG. 6, a ring-shaped container 3 is formed by using a pair of vertically divided half-ring-shaped containers 3 as shown in FIG. You may.

[0045]

According to the first aspect of the present invention, when the container tries to vibrate due to the vibration of the pole, the fluid sealed in the container swings in a direction to cancel the vibration, thereby suppressing the vibration of the pole. be able to. When the oscillation frequency is matched with the natural frequency of the pole, the natural vibration component of the pole is reduced, so the vibration of the pole is greatly reduced, and it is necessary to prevent the plastic deformation and breakage of the pole. Can be. In particular, it is possible to effectively dampen irregular and large-amplitude external vibrations such as earthquakes and traffic vibrations. Further, because of the vibration damping device using a fluid, inconveniences such as a collision sound and a scratch on a pole do not occur. Further, since the container constituting the vibration damping device is formed in a ring shape and is fitted around the pole, the appearance of the pole is not significantly impaired.
Furthermore, since it is attached to the installed pole by fitting it from the tip to the outside, the construction is reduced.

According to the second aspect of the present invention, since the ring-shaped container is vertically divided from substantially the center and formed into a half-ring shape, the pair of divided containers can be easily removed from both sides of the pole. Can fit. Even when the vibration damping device is mounted on the installed pole, it can be easily mounted.

According to the third aspect of the present invention, since a plurality of containers having substantially the same shape are externally fitted to the pole in a stacked state, the vibration damping performance is improved.

According to the fourth aspect of the present invention, since the amount of fluid sealed in a plurality of containers of substantially the same shape that are externally fitted on the pole and stacked is different, the swing frequency of each container is different. The oscillation characteristics of the vibration damping device obtained by synthesizing the oscillation characteristics of these containers show characteristics having a plurality of oscillation frequency peaks. Therefore, since the peak oscillation frequency has a range, the vibration damping performance is improved even if the oscillation frequency of the pole changes.

[Brief description of the drawings]

FIG. 1 shows a pole damping device according to an embodiment of the present invention, in which (a) is a front view of the pole and (b) is a schematic perspective view of the pole damping device.

FIG. 2 is a graph showing the vibration damping performance of the pole damping device of the above.

3A and 3B are graphs showing a temporal change in vibration acceleration in the above-described pole damping device. FIG. 3A shows a case where the damping device is not mounted on the pole, and FIG. 3B shows a case where the damping device is mounted on the pole. This is shown.

FIG. 4 is an exploded perspective view showing a vibration damping device for a pole different from that of the above embodiment of the present invention.

FIGS. 5A and 5B show a damping device for a pole different from the above-mentioned embodiment of the present invention, in which FIG. 5A is a perspective view and FIG. 5B is a graph showing a temporal change in vibration acceleration of a pole provided with the damping device. FIG.

FIGS. 6A and 6B show a damping device for a pole different from the above-mentioned embodiment of the present invention, wherein FIG. 6A is a perspective view and FIG. 6B is a graph showing a temporal change in vibration acceleration of a pole provided with the damping device. FIG.

FIG. 7 is a cross-sectional view showing an example of a conventional pole damping device.

FIG. 8 shows a conventional vibration damping device of a different pole from the above,
(A) is a longitudinal sectional view of a main part, (b) is a cross sectional view of a main part,
(C) is sectional drawing of the container which enclosed the fluid used same as the above.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pole 2 Fluid 2a Liquid surface 3 Container 3a Inner cylinder 3b Outer cylinder 3c Cover plate 3d Bottom plate 3 Container 4 Fixed piece 5 Ground 6 Arm 7 Lighting 8 Weight

Claims (4)

[Claims] 1. A pole damping device comprising a fluid sealed in a container, the container attached to a pole, and a swing frequency substantially equal to the natural frequency of the pole, wherein the container is formed in a ring shape. A damping device for a pole, wherein the container is fitted around the pole. 2. The pole vibration damping device according to claim 1, wherein the container is vertically divided from substantially the center. 3. The pole vibration damping device according to claim 1, wherein a plurality of containers having substantially the same shape are stacked. 4. The pole vibration damping device according to claim 3, wherein the amount of fluid sealed in each container is changed.