JP2014013067A - Vibration damping device and erect member with excellent vibration damping characteristics - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vibration damping device which has more excellent damping performance against vibration varying in a wide range of frequencies and is not affected by a direction of vibration, and to provide an erect member with excellent vibration damping characteristics.SOLUTION: A vibration damping device includes a bag body damper in which one or a plurality of bag bodies enclosing liquid inside and having flexibility are accommodated so as to be movable in a container. At least one of the bag bodies is a liquid enclosed large bag body enclosing one or a plurality of liquid enclosed small bag bodies each enclosing liquid in a bag smaller in size than the bag body and having flexibility. An erect member has the vibration damping device attached to the erect member.

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. Furthermore, in any of the methods, the vibration damping effect may depend on the direction of vibration depending on the design of the standing member or its accessory parts.

  Japanese Patent Application Laid-Open No. H10-228561 is based on such problems of the prior art, and is a vibration damping device including a bag body damper in which a flexible bag body in which a liquid is enclosed is movably accommodated in a container. An apparatus is described. It is disclosed that when the vibration damping device is attached to the outside or the inside of the vertical erection member, vibration due to the vibration applied to the vertical erection member can be attenuated.

JP 2011-241960 A

  However, the vibration damping device which is disclosed in Patent Document 1 and includes a bag damper in which a flexible bag body in which a liquid is sealed is accommodated in a container is movably accommodated is a vibration that varies widely. It was found that the vibration control effect on was insufficient.

  In view of such a situation, the object of the present invention is to have higher damping performance even for vibrations whose frequency fluctuates over a wide range, and to further improve the damping performance at the frequency at which the maximum effect is exhibited. An object of the present invention is to provide a vibration damping device that is not influenced by the direction and a standing member that is excellent in vibration damping.

  The present inventors have conducted various experiments and studies on a vibration damping device including a bag body damper in which a flexible bag body in which a liquid is sealed is accommodated movably in a container. The following findings (a) to (g) were obtained.

  (a) The number of bags contained in one container may be one or plural, and the number of containers containing bags may be one. There may be a plurality of them. The size of the bag body movably accommodated in one container may be appropriately selected according to the number of bag bodies. And if it was the bag body of the same dimension, the frequency which attenuate | damps did not change irrespective of the number of the bag bodies accommodated in a container. Moreover, if the volume ratio of the volume of the liquid sealed in the bag body to the maximum sealed amount in the bag body is within a range of 10 to 90%, the vibration frequency is reduced regardless of the weight sealed in the bag body. There was no change. It should be noted that the damping frequency did not change depending on the direction of vibration.

  (b) When this bag damper is attached to a structure such as a standing member, when the structure starts to vibrate, the liquid in the bag not only moves with a phase difference from the vibration of the structure, but also inside. Since the flexible bag body, which is made by enclosing a liquid such as water, is movable within the container, the vibration of the structure is attenuated by colliding with the inner wall of the container, thereby suppressing the vibration of the structure. I found out that I could do it. The vibration damping effect of this bag damper includes energy consumption due to mass transfer of liquid in the bag, energy consumption due to viscosity resistance of the liquid in the bag itself, and energy due to frictional resistance at the interface between the liquid in the bag and the bag. Multiple factors such as consumption, energy consumption due to the flexible bag body that itself is filled with liquid such as water, greatly deformed as the fluid moves, energy consumption due to collision with the inner surface of the container, etc. Is considered to be a combination.

(c) As described above, the number of bags constituting the bag damper may be one or plural, and the number of containers for storing the bags is one. There may be more than one. However, when a plurality of bags were used and the dimensions thereof were different from each other, a change was observed in the damping frequency regardless of the number of containers containing the bags. That is, only by accommodating a plurality of bags having different dimensions in one or a plurality of containers, a change was observed in the damping frequency. The phenomenon that the damping frequency changes by having multiple bag bodies with different dimensions in the bag damper is not related to the size of the weight enclosed in the bag body, but the maximum enclosed amount in the bag body. It was seen when the volume ratio of the volume of liquid to be enclosed was in the range of 10 to 90%.
(d) As a result of further investigation, the flexibility of sealing a liquid in a small-sized bag rather than simply storing a plurality of different-sized bags as a bag constituting the bag damper. One flexible liquid-filled large bag body (hereinafter referred to as “liquid-filled multiple bag body”) is formed by sealing one or a plurality of liquid-filled small bag bodies together with liquid in a large-sized bag body. It has been found that the damping performance of a bag damper (hereinafter referred to as “multiple bag damper”) accommodated in one or a plurality of containers is improved. In addition, a change is observed in the damping frequency by changing the size of the outer liquid-filled large bag of the liquid-filled multi-bag. Further, a bag damper that accommodates a plurality of liquid-filled multiple bag bodies having different dimensions of the outer liquid-filled large bag body has a wide range of damping frequencies. Note that the liquid-filled sachet to be sealed in the liquid-filled multiple-bag body may contain only the liquid inside, but in addition to the liquid, a liquid-filled sachet with a smaller size may be enclosed inside. .

  From the viewpoint of the damping performance of the multiple bag damper, it is preferable that the ratio of the total volume or the total weight of the small bag body to the total bag body in the multiple bag damper is 50% or more. % Has also been found to be particularly preferred. Here, the ratio of the total volume or the total weight of all the bag bodies in the multiple bag damper means that including the volume or the weight of the small bag body included in the liquid-filled multiple bag body.

  The vibration damping device including the multiple bag damper has higher damping performance. In addition, the present invention can be effective for vibrations whose frequency fluctuates over a wide range and is not affected by the direction of vibration. Therefore, by attaching to standing members such as lighting pillars, sign pillars, signal pillars, etc. that are erected on roads and bridges, etc., it has higher damping performance against vibrations whose frequency fluctuates over a wide range, and It is possible to impart vibration damping that is not affected by the direction of vibration.

  (e) The material of the bag used for the liquid-filled multi-bag damper is that the liquid enclosed in the bag can move freely without leaking from the bag, and the liquid moves in the bag. It is sufficient if the bag body with the liquid enclosed therein is flexible enough to freely change the shape of the bag body when it freely moves in the container. For example, polyethylene or rubber Examples thereof include a thin film of a polymer material having flexibility. The liquid to be sealed in the bag can be appropriately selected from water, a highly viscous liquid, a high-density liquid, etc., depending on the vibration frequency to be damped. The shape of the bag may be, for example, a spherical body made of polyethylene, or a pillow-shaped bag body in which a cylindrical plastic bag with a chuck is appropriately heat-sealed into a square, a rectangle or a circle, and a liquid is enclosed. It may be the one. If the plastic bag with a chuck | zipper is used, the volume of a bag body can be easily made into a desired value.

  (f) Regardless of the size of the bag body, the volume ratio of the volume of liquid enclosed in one bag body to the volume of the bag body is not particularly limited. Moreover, the dimension of a bag body is not specifically limited, What is necessary is just a dimension which can be accommodated in a container. The number of bags contained in one container may be one or plural. And the number of containers which accommodate a bag may be one or plural.

  (g) The shape of the container that movably accommodates a flexible bag formed by enclosing a liquid therein may be, for example, rectangular or spherical. If the bag body does not jump out of the container due to vibration, the container may not be provided with an upper cover, but a flat or hemispherical upper cover may be provided. When the upper lid is provided on the container, energy is consumed when the bag collides with the upper lid. Therefore, it is preferable to provide the upper lid on the container. In addition, a fluororesin film or an oil film may be stretched on the inner surface of the upper lid of the container so that the bag body in which the liquid is sealed is more easily moved in the container.

  The inner surface of the bottom surface of the container may be semispherical, or may be a rectangular parallelepiped shape in which the inner surface of the bottom surface is flat and has a side wall. Since a flexible bag formed by enclosing a liquid moves in the container and collides with the inner surface of the container, energy is consumed correspondingly, so a container shape that allows the bag to freely move in the container is preferable. . And as a material of a container, it is not specifically limited, For example, iron, stainless steel, and a plastic can be mentioned.

  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 (6) damping device and (7) standing member excellent in damping performance. Hereinafter, these may be collectively referred to as the present invention.

  (1) A vibration damping device comprising a bag damper in which one or a plurality of flexible bags formed by enclosing a liquid therein is movably accommodated in the container. At least one liquid-filled large bag having a flexibility in which one or a plurality of liquid-filled pouch bodies having a flexibility in which a liquid is sealed in a bag body smaller in size than the bag body is sealed. A vibration control device characterized by being a body.

  (2) The vibration damping device according to (1) above, wherein the ratio of the total volume of the liquid-filled sachets in all the sachets is 50% or more.

  (3) The vibration damping device according to (1) above, wherein the ratio of the total weight of the liquid-filled sachets in all the sachets is 50% or more.

  (4) The vibration damping device according to (1), wherein the bag damper container has a rectangular parallelepiped shape with a flat inner surface at the bottom and side walls.

  (5) The vibration damping device according to any one of (1) to (4) above, wherein the inner surface of the bottom surface of the container of the bag damper is a hemispherical shape.

  (6) The vibration damping device according to any one of (1) to (5) above, wherein the bag damper container has an upper lid.

  (7) A standing member comprising the vibration damping device according to any one of (1) to (6) above.

  According to the present invention, a damping device that has higher damping performance, can be effective even in vibrations whose frequency fluctuates over a wide range, and is independent of the direction of vibration, and has excellent vibration damping properties A member can be provided.

An example of the damping device which consists of a bag body damper concerning a comparative example is shown. An example of the damping device which consists of a bag body damper concerning a reference example is shown. (a) is a general view (perspective view), and (b) is an enlarged view (side view) around a bag damper. An example of the damping device which consists of a bag body damper concerning the present invention is shown. (a) is a general view (perspective view), and (b) is an enlarged view (side view) around a bag damper. In various bag body dampers, the frequency (Hz) and the damping constant (%) are plotted in a proportional relationship. It is the other contrast of what plotted frequency (Hz) and damping constant (%) in various bag dampers. It is the other contrast of what plotted frequency (Hz) and damping constant (%) in various bag dampers. It is the other contrast of what plotted frequency (Hz) and damping constant (%) in various bag dampers.

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

  FIG. 1 shows an example of a vibration damping device including a bag damper according to a comparative example. (a) is a general view (perspective view), and (b) is an enlarged view (side view) around a bag damper.

  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 including the bag body damper 11 is attached to the uppermost part of the steel pipe column 4. The bag body damper 11 includes one container 21 and one bag body 23 movably accommodated in the one container. The container 21 has a flat inner surface at the bottom, side walls, and a flat upper lid. And in this container, one of the bag bodies 23 which have the softness | flexibility formed by sealing water is accommodated movably.

  The container 21 that accommodates the bag is 300 mm wide × 300 mm deep × 70 mm high as the inner surface dimensions. And the bag body 23 which encloses a liquid inside used the cylindrical poly bag with a chuck | zipper of width 180mm x depth 180mm (henceforth "the poly bag a"). Two types of bags (hereinafter referred to as “bag body i” and “bag body ii”) were manufactured by sealing 770 g and 335 g of water in the plastic bag a with chuck, respectively. The bag dampers containing the respective bag bodies are referred to as “bag body damper A1” and “bag body damper A2”, respectively.

  Table 1 summarizes the specifications of the bag damper A1 and the bag damper A2 (number of bag bodies, bag body dimensions, and amount of enclosed water).

  FIG. 2 shows an example of a vibration damping device including a bag damper according to a reference example. (a) is a general view (perspective view), and (b) is an enlarged view (side view) around a bag damper.

  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 including the bag body damper 11 is attached to the uppermost part of the steel pipe column 4. The bag damper 11 includes two containers 21 and two bag bodies 23, and the bag bodies 23 are movably accommodated in the respective containers. Each container 21 has a flat inner surface at the bottom, side walls, and a flat top lid. And the flexible bag body 23 which encloses water is accommodated movably in each container.

  Each container which accommodates a bag body has a width of 164 mm, a depth of 164 mm and a height of 38 mm as the inner surface dimensions. The containers are stacked vertically and the overall height is 109 mm. And as the bag body 23 which encloses the liquid inside, a cylindrical poly bag with a chuck having a width of 135 mm × depth of 135 mm (hereinafter referred to as “poly bag d”) and a cylindrical shape having a width of 160 mm × depth of 160 mm. The plastic bag with a zipper (hereinafter referred to as “polybag b”) is used, and each of the polybags is filled with 192.5 g of water, whereby two types of bags (“bag body iii” and “bag”). Body iv ”).

  The upper container contained a bag body iii, and the lower container contained a bag body iv. Hereinafter, the damper in which the two bag bodies 23 having different dimensions are movably accommodated in the respective containers is referred to as “bag body damper B1”.

  Table 2 shows the specifications of the bag damper B1 (the number of bag bodies, the bag body dimensions, and the amount of enclosed water).

  FIG. 3 shows an example of a vibration damping device including the bag damper according to the present invention. (a) is a general view (perspective view), and (b) is an enlarged view (side view) around a bag damper.

  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 including the bag body damper 11 is attached to the uppermost part of the steel pipe column 4. The bag body damper 11 is a liquid-filled multiple bag body damper, and is accommodated in one container 21. The flexible multiple bag body includes an inner small bag body 23a and an outer large bag body 23b, and liquid is sealed in both the small bag body and the large bag body. The liquid-filled large bag body 23b in the container is movably accommodated in the container, and the liquid-filled small bag body 23a is movably accommodated in the liquid-filled large bag body 23b. The container 21 has a flat inner surface at the bottom, side walls, and a flat upper lid.

  The container 21 that accommodates the bag body has a width of 300 mm, a depth of 300 mm, and a height of 70 mm as inner surface dimensions. A small bag body and a large bag body constituting the multiple bag body include a plastic bag a with a chuck (width 180 mm × depth 180 mm), a plastic bag b with a chuck (width 160 mm × depth 160 mm), a tube 140 mm × depth 140 mm. Two types of plastic bags with a zipper (hereinafter referred to as “polybag c”) and cylindrical plastic bags with a chuck having a width of 120 mm × depth of 120 mm (hereinafter referred to as “polybag e”). Was used. Each of the plastic bags with chucks was filled with water shown in Table 3 to produce five types of liquid-filled multiple bag dampers C1 to C5. Table 3 summarizes these specifications.

  Each of these liquid-filled multi-bag dampers C1 to C5 is attached to the upper part of a steel tube column having an outer diameter of 34 mm with its lower end fixed, and the length of the steel tube is set to 4. so that the natural frequency becomes 2 to 14 Hz. Free vibration experiments were conducted at 0, 3.2, 2.8, 2.5, 2.1, 1.8 and 1.5 m, respectively. For comparison, a free vibration experiment was performed in the same manner for one bag damper (A1, A2) and two bag dampers (B1) having different dimensions.

  FIG. 4 is a plot of frequency (Hz) and damping constant (%) for A1, C1, and C2 having a total weight of sealed water of 770 g among these liquid-filled bag dampers. The three liquid encapsulated bag dampers not only have the same total weight of the encapsulated water, but also have the same outer bag dimensions. As can be seen from this plot, the multiple bag dampers C1 and C2 have a higher damping performance than one bag damper A1, and have a damping effect for vibrations in a wide range of frequencies of 2 to 8 Hz. I understand that. Moreover, when the multiple bag dampers C1 and C2 are compared, it can be seen that the greater the liquid weight of the inner bag, the higher the damping performance.

  FIG. 5 is a plot of frequency (Hz) and damping constant (%) for A2, B1, C3, and C4 having a total water content of 385 g among these liquid-filled bag dampers. Among these, A2, C3 and C4 not only have the same total weight of the sealed water, but also have the same outer bag size. As can be seen from this plot, the multiple bag dampers C3 and C4 have a higher damping performance than one or two single bags, and have a damping effect on vibrations in a wide range of frequencies from 2 to 5 Hz. You can see that In addition, it can be seen that B1 is effective in a wider frequency range by changing the size of the upper and lower bags, and the peak damping constant is lower than C3 and C4, but the size of the bag is changed. Thus, it can be seen that the controllable frequency range can be widened. When the multiple bag dampers C3 and C4 are compared, it can be seen that the larger the liquid capacity of the inner bag, the higher the damping performance.

  FIG. 6 is a plot of frequency (Hz) and damping constant (%) for A2, C3, and C5 with a total water content of 385 g of these liquid-encapsulated bag dampers. The three liquid encapsulated bag dampers not only have the same total weight of the encapsulated water, but also have the same outer bag dimensions. However, C5 increases the weight of the inner bag and reduces the amount of water in the outer bag. As can be seen from this plot, the multiple bag dampers C3 and C5 have higher damping performance than one single bag damper, and are capable of damping vibrations in a wide range of frequencies from 2 to 5 Hz. It turns out that it has an effect. When the multiple bag body dampers C3 and C5 are compared, it can be seen that the larger the liquid weight of the inner bag body, the higher the damping performance.

  FIG. 7 is a plot of frequency (Hz) and damping constant (%) for A2, C4, and C5 with a total water content of 385 g among these liquid-filled bag dampers. The three liquid encapsulated bag dampers not only have the same total weight of the encapsulated water, but also have the same outer bag dimensions. However, C5 increases the weight of the inner bag and reduces the amount of water in the outer bag. As can be seen from this plot, the multiple bag dampers C4 and C5 have higher damping performance than one single bag damper, and are capable of damping vibrations in a wide range of frequencies from 2 to 5 Hz. It turns out that it has an effect. When the multiple bag body dampers C4 and C5 are compared, it can be seen that the larger the liquid weight of the inner bag body, the higher the damping performance. Considering the result of C3 shown in FIG. 5 together, it can be said that the damping performance improves as the weight and the volume of the inner bag body increase from the mutual comparison of C3, C4, and C5.

  As described above, it is possible to provide a damping device and a standing member excellent in damping performance that have higher damping performance, are effective for vibrations whose frequency fluctuates over a wide range, and are not affected by the direction of vibration. be able to.

2 Standing Member 3 Foundation 4 Steel Pipe Pillar 11 Bag Damper 21 Container 23 Bag 23a Inner Small Bag 23b Outer Large Bag 24 Mounting Tool

Claims (7)

  A damping device comprising a bag damper in which one or a plurality of flexible bags formed by enclosing a liquid therein are movably accommodated in the container, wherein at least one of the bags Is a flexible liquid-filled large bag body in which one or a plurality of flexible liquid-filled small bag bodies are formed by enclosing a liquid in a bag body having a size smaller than that of the bag body. A vibration damping device characterized by that.   The vibration damping device according to claim 1, wherein the ratio of the total capacity of the liquid-filled sachets in all the bags is 50% or more.   2. The vibration damping device according to claim 1, wherein a ratio of the total weight of the liquid-filled sachets in all the bags is 50% or more.   2. The vibration damping device according to claim 1, wherein the container of the bag body damper has a rectangular parallelepiped shape having a flat bottom surface and a side wall.   The damping device according to any one of claims 1 to 4, wherein the bag damper container has a semispherical inner surface at the bottom.   The damping device according to any one of claims 1 to 5, wherein the bag damper container has an upper lid.   A standing member to which any one of the vibration damping devices according to claim 1 is attached.

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