JP5134498B2 - Vibration control device and standing member with excellent vibration control - Google Patents

Description

  The present invention relates to a vibration damping device and a standing member excellent in vibration damping performance. In particular, the present invention relates to a vibration control device used for a standing member such as an illumination column, a sign column, a signal column, and the like standing on a road or a bridge, and a standing member excellent in vibration damping.

  A standing member such as an illumination column, a sign column, or a signal column installed on a road or a bridge may shake due to a resonance phenomenon caused by a wind, an earthquake, a road surface vibration caused by traveling of a vehicle, or the like. When these standing members swing, the standing members are easily damaged by the swing, and the damage is promoted. In addition, there is a problem that the life of the instrument attached to the standing member is shortened due to the generated vibration. Further, in the case of the illumination column, there is a problem that the illumination light is shaken and the person feels uncomfortable.

In order to prevent the standing member from shaking due to such a resonance phenomenon,
(a) A method of changing the natural frequency by changing the weight, shape and rigidity of the standing member,
(b) A method of providing a physical pendulum and a contact tool inside the standing member and having a vibration damping effect by causing the physical pendulum to collide with the contact tool during vibration,
However, each has already been proposed.

  However, although the method (a) has a damping effect for a specific frequency, it cannot cope with fluctuations in which the excitation cycle and frequency fluctuate variously, such as fluctuations caused by wind. As a result, the degree of freedom in the material design of the standing member is reduced. In addition, in the method (b) above, in addition to not being able to cope with fluctuations in which the excitation cycle and frequency fluctuate variously, in order to increase the vibration damping effect, the physical pendulum and the abutment tool must be larger than a certain size. It is necessary to be safe. For this purpose, a storage space is required, which also reduces the degree of freedom in designing the standing member.

  In Patent Document 1, in light of such problems of the prior art, a steel chain or a wire is suspended with a non-fixed free vibration part inside a vertical hollow body, and the steel chain or A vibration damping device is described that accommodates fluctuations in the frequency by maintaining an equal spacing between the wire and the inner wall of the vertical hollow body. By attaching the vibration damping device to the outside or the inside of the vertical erection member, the vibration caused by the vibration applied to the vertical erection member is attenuated.

  Furthermore, Patent Document 2 describes a vibration damping device in which a plurality of spherical bodies are accommodated in a container having a curved inner surface at the bottom, and each spherical body in the container is movably accommodated in the container. ing. And in addition to what accommodated such a spherical body in the container, the damping device which suspends suspension members, such as a steel chain, inside the vertical hollow body is also described.

Japanese Patent Publication No. 04-26004 JP 2008-69861 A

  Even if the vibration control device described in Patent Document 1 or 2 above is incorporated in standing members such as lighting columns, sign columns, and signal columns, the vibrations are caused by resonance phenomena caused by wind, earthquakes, road surface vibrations associated with vehicle travel, etc. The installation member sometimes shook. And if these standing members are shaken, the generated vibration shortens the life of the equipment attached to the standing members.Furthermore, in the case of an illumination column, the illumination light is shaken and the person feels uncomfortable. give.

  This is because, in the vibration damping device described in Patent Document 1, in the case of vibrations caused by wind, earthquake, road surface vibrations associated with vehicle travel, etc., the frequency range is wide, so This is because it is not possible to deal with vibrations in the entire frequency range by simply suspending the steel chain. In particular, it has been found that the damping effect for low frequency vibrations of 1 to 2 Hz is insufficient.

  Further, in the vibration damping device described in Patent Document 2, a plurality of spherical bodies are accommodated in a container having a curved inner surface on the bottom surface so that each spherical body in the container can move within the container. Therefore, it has a high damping performance even for vibrations whose frequency fluctuates in a wide range from high frequency to low frequency, and can obtain an excellent damping effect, and has a low frequency of 1-2 Hz. The damping effect on the vibration of the frequency is sufficient. However, the damping effect for vibrations with a high frequency of about 5 Hz is not limited to the damping device in which such a spherical body is accommodated in the container, but a suspension member such as a steel chain is provided inside the vertical hollow body. It was found to be inadequate, including the damping device that was suspended.

  In view of such a situation, the object of the present invention is to provide a high damping performance in a wide range of frequencies, including vibrations whose frequencies vary from a high frequency to a low frequency, and are independent of the direction of vibration. An object of the present invention is to provide a vibration device and a standing member excellent in vibration damping.

  As a result of various experiments and examinations, the present inventors have obtained the findings shown in the following (a) to (g).

  (a) It is preferable that the damping effect against vibrations at a low frequency is exhibited by accommodating a plurality of granular materials in a container having a curved inner surface at the bottom. That is, when such a container is attached to a structure such as a standing member, it is attached to the structure when the structure starts to vibrate at a low frequency such as traffic vibration or earthquake based on vehicle running. The plurality of granulates in the container thus started to vibrate. In this case, the inner surface of the bottom surface of the container has a curved surface shape, and the plurality of granular materials are movable in the container. Therefore, between the granular materials or between the granular material and the inner wall of the container. The frictional force and the inertial force caused by the vibration of the plurality of granular materials in the phase opposite to that of the structure can attenuate the vibration of the structure, thereby suppressing the low frequency vibration of the structure.

  (b) Next, it has been found that the damping effect on vibrations at a high frequency can be exhibited by using a container whose outer surface on the bottom surface has a curved surface and swingably supporting at the lower end of the bottom surface. For example, by placing a container on a flat plate having an elastic member below and connecting a lower end of the bottom of the container and a lower end of the elastic member with a wire through a hole made in the flat plate, Can be swingably supported at the lower end of the bottom surface. That is, a container having a curved outer surface on the bottom surface is placed on a flat plate, and the lower end of the bottom surface of the container is fixed with a wire through an elastic member made of a spring material or a rubber material. Since the inertia moment which has can be utilized, a container is rockably supported in the lower end part of the bottom face.

  When such a container is swingably attached to a structure such as a standing member, when the structure starts to vibrate at a high frequency such as wind excitation, the outer surface of the bottom surface has a curved shape. The elastic member supporting the container together with the wire is deflected, and the container starts an arc motion in the opposite phase to the vibration of the structure. At that time, a force having a phase opposite to the vibration of the structure acts due to the moment of inertia with the fixed portion of the elastic member as a fulcrum, thereby suppressing the vibration of the structure having a high frequency.

  Here, as the flat plate on which the container is placed, for example, a steel plate or a stainless steel plate can be used. And the flat plate which mounts a container may be one member of structures, such as a standing member, and may be a member different from a structure. In order to fix one end of the wire rod to the lower end portion of the bottom surface of the container, for example, the wire rod is passed through a hole drilled in the lower end portion of the bottom surface of the container, and a stopper may be attached. Moreover, what is necessary is just to attach a stopper similarly in order to fix the other end of a wire to the lower end part of an elastic member.

  As will be described later, the elastic constant of the elastic member is preferably set to a value synchronized with the frequency applied to the structure according to the weight of the container and the spherical body.

  (c) In this way, a plurality of granular bodies are accommodated in a container having an inner and outer surface of the bottom surface having a curved shape, and the container is supported at the lower end portion of the bottom surface so as to be swingable, thereby achieving a high frequency. It can be set as the damping device which has high damping performance in any low frequency. Moreover, since this container is a right-and-left object shape, it can be set as the damping device which does not depend on the direction of vibration. Further, when the vibration damping device described in Patent Document 1 is incorporated, the impact noise of the suspension member of the steel chain is generated, so it is problematic to use it for a standing member standing in a residential area or the like. However, this vibration damping device has an advantage of being quiet because it only generates a rubbing sound between the granular materials or a sound of the granular materials hitting the inner wall of the container.

  (d) This container is required to have a curved inner surface and outer surface. The curved shape of the inner and outer surfaces of the bottom surface may be an egg shape or a shell shape in addition to the spherical shape. The specific shape of the container may be a spherical container as a whole, but preferably has an upper lid. This is because if the container has an upper lid, energy is absorbed when the granular material in the container collides with the upper lid, and the vibration is attenuated accordingly. At this time, the inner surface of the upper lid may be either a planar shape or a curved surface shape, but a planar shape is more preferable. The top lid is easy to remove when attached to the container by screwing. The material of the container is not particularly limited, and examples thereof include iron, stainless steel, and plastic.

  (e) The granular material movably accommodated in the container is a frictional force between the granular materials or between the granular material and the inner wall of the container, or the plurality of granular materials vibrate in an opposite phase to the structure. Because the inertial force due to dampens the vibrations of structures such as standing members and can suppress the vibrations of the structures, the granular material should have a certain weight or more depending on the vibrations to be damped. Is preferred. From this viewpoint, it is preferable to use a material having a high density such as lead or iron as the granular material. The granular material preferably has an outer diameter of 1 to 20 mm, and the plurality of granular materials preferably have the same shape. The shape of the granule is preferably a sphere, but may be a substantially spherical shape such as an egg shape or a shell shape.

  (f) As an elastic member that is provided at the lower end of the curved surface of the container and supports the container in a swingable manner, a spring material such as a winding spring or a leaf spring, or a rubber material can be used. And as a material of a wire, a steel wire, a nylon wire, etc. can be used. In addition, it is preferable to set it to the value which synchronizes with the frequency added to a structure according to the weight of a container and a spherical body by selecting suitably the elastic constant of elastic bodies, such as a spring material. This is because it is possible to further improve the damping performance against vibrations in a low frequency range such as earthquakes and traffic vibrations. For example, by damping the spring constant of a spring member that supports the bottom of a hollow container whose inner and outer surfaces are curved, the damping is focused on the damping effect against low frequency vibrations. It is also possible to configure the device.

  (g) And by attaching such vibration control devices to standing members such as lighting columns, sign columns, signal columns, etc., standing on roads and bridges, etc. In addition to having high damping performance at any frequency, it is possible to impart damping performance that is not affected by the direction of vibration.

The vibration damping device and the standing member excellent in vibration damping performance according to the present invention have been completed based on these findings. The gist of the present invention is the following (1) to (9) damping device and (10) standing member having excellent damping performance. Hereinafter, these may be collectively referred to as the present invention.

(1) A vibration damping device in which a plurality of granular materials are accommodated in a container having a curved inner surface and an outer surface, and the container is placed on a flat plate having an elastic member below. Damping, characterized in that the container is swingably supported at the lower end of the bottom by a wire connecting the lower end of the bottom of the container and the lower end of the elastic member through the perforated hole apparatus.

(2) The vibration damping device according to (1) above , wherein the container is spherical as a whole .

(3) The vibration damping device according to (1) or (2) above, wherein the container has an upper lid .

(4) The vibration damping device according to any one of (1) to (3) above, wherein the inner surface of the upper lid has a planar shape .

(5) The vibration damping device according to any one of (1) to (4) above, wherein the inner and outer surfaces of the bottom surface of the container are hemispherical .

(6) The vibration damping device according to any one of (1) to (5) above, wherein the outer diameter of the granular material is 1 to 20 mm .

(7) The vibration damping device according to any one of (1) to (6) above , wherein the granular material is a sphere .

(8) The vibration damping device according to any one of (1) to (7), wherein the plurality of granular bodies have the same shape.

(9) The vibration damping device according to any one of (1) to (8) above, wherein a spring is used as the elastic member.

(10) A standing member excellent in vibration damping, wherein the vibration damping device according to any one of (1) to (9) is attached.

  The present invention has a high damping performance in a wide range of vibrations even in vibrations whose frequencies vary from a high frequency to a low frequency, and is excellent in vibration damping devices and vibration damping properties that are not influenced by the vibration direction. A standing member can be provided.

  Hereinafter, the present invention will be described with reference to the drawings. Here, the effect of the present invention was demonstrated using a small experimental apparatus. The present invention is not limited to the following examples.

  FIG. 1 is a schematic view of an example when the vibration damping device according to the present invention is attached to a column head of a standing member. (a) is a longitudinal sectional view of the standing member, and (b) is an enlarged sectional view of the top of (a).

  The standing member 2 such as an illuminating column is formed by standing a steel pipe column 4 having a circular cross section on a foundation 3. The vibration damping device 1 covers a flat lid 21 after a plurality of granular bodies 22 are accommodated in a container whose inner and outer surfaces of the bottom surface 20 are hemispherical so as to be movable in the container. Is configured to be swingably supported at the lower end of the bottom surface.

  Here, the container is placed on a flat plate 10 having a winding spring 30 below, and passes through a hole (not shown) drilled in the flat plate 10 and the bottom end of the bottom of the container and the winding spring 30. The container is swingably supported at the lower end portion of the bottom surface by the wire 31 connecting the lower end portions. Since both ends of the wire rod are provided with stoppers 32, one end is fixed to the inner surface of the lower end portion of the bottom surface of the container, and the other end is fixed to the lower end portion of the winding spring 30.

  For vibrations with a low frequency, the movable granular material in the container exhibits a damping effect. When the steel pipe column 4 that constitutes a standing member such as an illumination column starts vibration at a low frequency such as traffic vibration or earthquake based on vehicle travel, the plurality of granular bodies 22 in the container start to vibrate. Since the plurality of granular bodies 22 are movable in the container, the frictional force between the granular bodies or between the granular bodies and the inner wall of the container, or the plurality of granular bodies vibrate in the opposite phase to the structure. An inertial force is generated, and the vibration of the steel pipe column 4 is damped, so that the low frequency vibration can be suppressed.

  As shown in FIG. 2, the swingable container exhibits a damping effect against vibrations with a high frequency.

  FIG. 2 is an explanatory view (a longitudinally enlarged cross-sectional view of the top portion of the standing member) of the vibration damping mechanism at a high frequency of the vibration damping device shown in FIG. 1.

  When the steel pipe column 4 constituting a standing member such as an illuminating column receives a dynamic external force due to the wind and starts to vibrate at a high frequency due to the excitation of the wind, the container is swingably supported at the lower end of the bottom surface of the container The winding spring 30 is bent, and the container starts an arc motion in an antiphase with respect to the vibration of the steel pipe column 4. At that time, due to the moment of inertia with the fixed portion at the upper end of the winding spring 30 as a fulcrum, a force having a phase opposite to that of the vibration of the steel pipe column 4 works, and the vibration of the steel pipe column 4 can be suppressed.

  Table 1 shows the specifications of the container and the spring constituting the vibration damping device of this embodiment. Table 2 shows the specifications of a standing member (steel pipe column) to which the vibration damping device is attached.

  FIG. 3 shows the result of measuring the change in acceleration of the column head along with the measurement time by freely vibrating the steel pipe column 4 with respect to the standing member 2 to which the vibration damping device 1 is attached.

  From FIG. 3, the vibration damping constant in part A is obtained as follows.

Damping constant h = logarithmic decay rate δ / 2π = 0.411 / 2π = 6.54 (%)
The method for obtaining the attenuation constant h is as follows. In FIG. 3, since the vibration occurs in the order of α1 → α2 → α3, the logarithmic attenuation rate δ is as shown in the following equations.

Logarithmic decay rate δ _{α1 → α2} = log _e (| α1 / α2 |)
Logarithmic decay rate δ _{α2 → α3} = log _e (| α2 / α3 |)
Since the logarithmic decay rate δ of part A is the average of these,
δ = log _e (| α1 / α3 |) / 2 = log _e (| 11.6 / 5.1 |) = 0.411
It becomes.

Therefore, the damping constant h is
Damping constant h = logarithmic decay rate δ / 2π = 0.411 / 2π = 6.54 (%)
It becomes.

  Next, an experiment was performed in which the damping device was attached to each of six steel pipe columns having different lengths, and the steel pipe columns were freely vibrated to measure the damping constant and the frequency. Table 3 shows the specifications of the six steel pipe columns. The specifications of the container and the spring constituting the vibration damping device are as described in Table 1.

  FIG. 4 shows the results of measuring the damping constant and frequency using the vibration damping device (FIG. 1) according to the present invention. Here, this measurement result measured twice about six steel pipe columns from which length differs, and showed the average value. For comparison, the measurement results of Comparative Example 1 (FIG. 5) described later are also shown in FIG. Moreover, the comparison with the measurement result of the comparative example 2 (FIG. 6) mentioned later was shown in FIG.

  It can be seen that the vibration damping device according to the present invention exhibits a high vibration damping effect at both frequencies of 2 Hz and 5 Hz.

Comparative Example 1

  FIG. 5 is a schematic diagram of an example when the vibration damping device described in Patent Document 1 is attached to the column head of the standing member. (a) is a longitudinal cross-sectional view of standing members, such as an illumination pillar, (b) is an expanded sectional view of the top part of (a).

  The standing member 2 such as an illuminating column is formed by standing a steel pipe column 4 having a circular cross section on a foundation 3. And the damping device 1 covers the planar top cover 21 after accommodating the plurality of lead spherical bodies 22 in a container having the curved inner surface of the bottom surface 20 so that the lead spherical body 22 can move inside the container. It consists of one container.

  Table 4 shows the specifications of the container constituting the vibration damping device of Comparative Example 1. The specifications of the standing member (steel pipe column) to which this vibration damping device is attached are as described in Table 3.

  In addition, about the standing member which attaches the damping device concerning this comparative example 1 to a steel pipe pillar, the steel pipe pillar was vibrated freely, and the result of having measured the damping constant and the frequency is the damping device ( FIG. 4 shows a comparison with the measurement result in FIG.

  As a result, it was found that the vibration damping device according to Comparative Example 1 exhibits a high vibration damping effect at a frequency of 2 Hz, but hardly exhibits a vibration damping effect at a frequency of 5 Hz.

Comparative Example 2

  FIG. 6 is a schematic view of another example when the vibration damping device described in Patent Document 1 is attached to the column head of the standing member. (a) is a longitudinal cross-sectional view of standing members, such as an illumination pillar, (b) is an expanded sectional view of the top part of (a).

The standing member 2 such as an illuminating column is formed by standing a steel pipe column 4 having a circular cross section on a foundation 3. The vibration damping device is configured such that a plurality of lead granules 22 are accommodated in a container having an inner surface of the bottom surface 20 having a curved shape so as to be movable in the container, and a flat upper cover 21 is placed thereon. In addition to the container, it is configured by combining a steel pipe column 4 as a vertical hollow body with a steel chain 11 suspended therein. In addition, it is suspended so that the axial center of the steel chain 11 and the axial center of the steel pipe pillar 4 as the vertical hollow body 10 may correspond.

The specifications of the two containers and the standing members (steel pipe columns) constituting the vibration damping device of Comparative Example 2 are as described in Table 3. The steel chain 11 has a length of 500 mm, and a link of steel links (diameter 6 mm) having a length of 30 mm and a width of 21 mm as one link was suspended.

  FIG. 7 shows the results of measuring the damping constant and the vibration frequency of the standing member formed by attaching the vibration damping device according to Comparative Example 2 to the steel pipe column, by freely vibrating the steel pipe column. For comparison, the measurement results with the vibration damping device according to the example (FIG. 1) are also shown in FIG.

  As a result, it was found that the vibration damping device according to Comparative Example 2 exhibits a high vibration damping effect at a frequency of 2 Hz, but does not have a significant vibration damping effect at a frequency of 5 Hz. In addition, compared with the vibration damping device according to Comparative Example 2, the vibration damping device according to the embodiment also has an advantage that the weight is small.

  As described above, according to the present invention, a vibration damping device and a vibration damping device that have high damping performance in a wide range of vibrations and that do not depend on the vibration direction, even for vibrations that vary in frequency from high frequencies to low frequencies. The standing member excellent in property can be provided.

It is a schematic diagram of an example when the damping device which concerns on this invention is attached to the column head of a standing member. (a) is a longitudinal sectional view of the standing member, and (b) is an enlarged sectional view of the top of (a). It is explanatory drawing (longitudinal expansion sectional drawing of the top part of a standing member) of the damping mechanism in the high frequency of the damping device shown in FIG. About the standing member which attaches the damping device shown in FIG. 1, a steel pipe column is vibrated freely, The result of having measured the change of the acceleration of a column head is shown with measurement time. The result of having measured the damping constant and the frequency using the damping device which concerns on an Example (FIG. 1) and the damping device which concerns on the comparative example 1 (FIG. 5) is shown. It is a schematic diagram of an example (comparative example 1) when the damping device described in patent document 1 is attached to the column head of a standing member. (a) is a longitudinal cross-sectional view of standing members, such as an illumination pillar, (b) is an expanded sectional view of the top part of (a). It is a schematic diagram of the other example (comparative example 2) when the damping device described in patent document 1 is attached to the column head of a standing member. (a) is a longitudinal cross-sectional view of standing members, such as an illumination pillar, (b) is an expanded sectional view of the top part of (a). The result of having measured a damping constant and a frequency using the damping device concerning an example (Drawing 1) and the damping device concerning a comparative example 2 (Drawing 6) is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Damping device 2 Standing member 3 Foundation 4 Steel pipe pillar 10 Flat plate 11 Steel chain 20 Bottom of container 21 Upper lid of container 22 Granule 30 Winding spring 31 Wire 32 Stopper

Claims (10)

A vibration damping device in which a plurality of granular bodies are housed in a container having a curved inner surface and outer surface, and the container is placed on a flat plate having an elastic member below, and is drilled in the flat plate A vibration damping device , wherein a container is swingably supported at a lower end portion of a bottom surface of a container by a wire rod that passes through a hole and connects a lower end portion of the bottom surface of the container and a lower end portion of an elastic member . The vibration damping device according to claim 1 , wherein the container has a spherical shape as a whole. Container and having a top cover, the vibration damping device according to claim 1 or 2. The vibration damping device according to any one of claims 1 to 3 , wherein an inner surface of the upper lid has a planar shape. The vibration damping device according to any one of claims 1 to 4 , wherein the inner and outer surfaces of the bottom surface of the container are hemispherical. 6. The vibration damping device according to claim 1, wherein the outer diameter of the granular material is 1 to 20 mm. The vibration damping device according to any one of claims 1 to 6 , wherein the granular material is a sphere. The damping device according to any one of claims 1 to 7 , wherein the plurality of granular bodies have the same shape. The vibration damping device according to any one of claims 1 to 8 , wherein a spring is used as the elastic member. A standing member excellent in vibration damping, wherein the vibration damping device according to any one of claims 1 to 9 is attached.

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