JPH09189340A - Damping structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively suppress vibration of a structural body caused by impact applied in the structural body having a long and narrow inner space from the outside by forming a hollow drum part of specific volume in the inside of a cylindrical formed body composed of an organic high polymer material provided in the inner space of the structural body. SOLUTION: In a damping structural body, a cylindrical expanded body 2A is provided in an inner space 15A of a pipe body 1A having a cylindrical section and the cylindrical expanded body 2A is closely stuck to the internal wall face of the pipe body 1A in an arbitrary section perpendicular to the shaft of the pipe body 1A. The volume of a hollow drum body 3A of the cylindrical expanded body 2A occupies not more than 80% and not less than 30% of the inner space 15A of the pipe body 1A. This constitution cam provide the damping structure with superior damping performance, reduce the sounding quantity in applying impact, enhance decelerating speed in applying the impact, and extremely improve noise reducing effects.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration damping structure which is suitable as a vibration damping member and a vibration damping structural material and has excellent vibration absorbing performance.

[0002]

2. Description of the Related Art In recent years, as a part of improvement of product performance and improvement of working space environment, there has been a particularly high demand for reducing noise for which measures have been delayed. Since sound is generated by the vibration of an object, it can be said that the most efficient noise reduction is to use a structural member having excellent vibration absorbing performance that can eliminate the resonance and resonance phenomenon of the structural member of the vibration system.

Conventionally, the mechanical members, the columns of the structure, the shafts for power transmission, etc. have been made light in weight for the purpose of increasing the cost and increasing the power transmission efficiency due to the increase in size of the structure. The tubular body is often used because of its high rigidity. However, the columns and shafts of the machine and the structure have a drawback that they are resonated by the vibration of the machine or the like and amplify the vibration to easily generate noise. Therefore, countermeasures are required from the viewpoint of not only noise pollution but also improvement of the working environment.

However, in most cases, these columns and shafts are firmly connected to a machine or the like on the mechanism, and it is mechanically impossible to connect the machine or the like to the columns or the shaft through a vibration insulator. In many cases Generally, as means for preventing vibration, (1) increase weight or strengthen rigidity, (2) avoid resonance, (3)
There are only three principles of vibration damping. However, in the case of a pipe, even if the plate thickness used is thick or a solid rod is used,
Although the resonance frequency can be changed by increasing the weight, no vibration damping effect can be seen. Therefore, conventionally, resonance has been avoided. In other words, by attaching a heavy object to a specific place and locally increasing the weight, the resonance frequency of the tubular body is shifted to a point different from the frequency of the vibration source, thereby avoiding vibration amplification due to resonance. Was there. However, since it is impossible to obtain the effect only when the frequency band of the vibration source is narrow and it is impossible to shift the resonance point to the outside of the audible sound range, it is not possible to exert a practical soundproofing effect on all machines etc. Absent.

On the other hand, in the case of a steel plate, many means are known as means for imparting vibration energy to the structural member itself for the purpose of damping vibration. For example, Japanese Patent Publication No. 39-12451 and Japanese Patent Publication No. 45-34.
Japanese Patent No. 703 or the like discloses a damping steel plate in which a viscoelastic body having a high mechanical loss rate is sandwiched between two steel plates. However, the vibration damping tube in which such a sandwich structure is applied to the tubular body and the viscoelastic substance is sandwiched between the tubular bodies of the double pipe structure has a high vibration damping property unlike the case of the steel plate. I can't do that.

Therefore, the inventors of the present invention have previously reported that the Japanese Patent Publication No. 63-63
In Japanese Patent Publication No. 9978, it is disclosed that when a viscoelastic body is filled in the entire tubular body, a significant vibration damping effect is exhibited. Although the above-mentioned method has a sufficient vibration damping property, the weight is increased, and there is a problem that the horsepower of a drive source such as a motor is unavoidably increased. Further, it was unsuitable for the purpose of using the shaft through the inside of the tubular body.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to effectively suppress the vibration of a structure having an elongated inner space from the outside and to reduce the weight of the structure. It is to provide a vibration control structure.

[0008]

SUMMARY OF THE INVENTION The present invention is a vibration damping structure for suppressing vibration of a structure having an elongated inner space due to an impact applied from the outside thereof. A tubular molded body made of an organic polymer material provided in a space is provided, a hollow portion is provided inside the tubular molded body, and the tubular molded body includes at least a tubular foamed body. The outer peripheral surface of the tubular foam adheres to at least a part of the inner wall surface of the structure in an arbitrary cross section perpendicular to the axis of the structure, and the surface of the tubular molded body on the cavity side is constrained. It is exposed to the cavity without being blocked, and the volume of the cavity occupies 30% or more and 80% or less of the volume of the inner space of the structure. is there.

[0009]

The present inventor provides a vibration damping structure which can effectively suppress the vibration of a structure having an elongated inner space due to an impact applied from the outside thereof and is lightweight. As a result of various studies, the tubular molded body was fixed in the inner space of the structure, and the tubular body was formed on at least a part of the inner wall surface of the structure in an arbitrary cross section perpendicular to the axis of the structure. The molded body is made to adhere closely, at least a part of the cylindrical molded body is made into a tubular foam, and the volume of the hollow portion of the cylindrical molded body is set to 30% to 80% of the volume of the inner space, thereby significantly reducing the vibration damping structure. It was found that the body can be made lighter and high vibration damping performance can be obtained at the same time. That is, by satisfying all of the above requirements, the vibration damping structure exhibits excellent vibration damping performance, the amount of sound generated when a shock is applied is reduced, and the damping speed when a shock is applied is also increased. The present invention has been completed based on the finding that the noise reduction effect is extremely high. Moreover, by making 30% to 80% of the volume of the inner space of the structure hollow, the weight of the vibration damping structure is significantly reduced, and at least a part of the vibration damping structure is made of a tubular foam. The weight of the tubular composite is further reduced. Further, it has become possible to pass the shaft through the hollow portion of the tubular molded body.

[0010]

EXAMPLE First, an example will be described in which the above structure is a tubular body having one elongated inner space, and one cylindrical molded body is fixed to this inner space. 1, 2, and 3
FIG. 4 is a cross-sectional view of each damping structure according to an example of the present invention, taken in a direction perpendicular to the central axis of the tubular body.

In the vibration damping structure shown in FIG. 1, a cylindrical foam body 2A is provided in an inner space 15A of a tubular body 1A having an annular cross section, and an arbitrary shape perpendicular to the axis of the tubular body 1A is provided. The cylindrical foam 2A is in close contact with the inner wall surface of the tubular body 1A in cross section. Cavity 3 of cylindrical foam (molded body) 2A
The volume of A occupies 30% or more and 80% or less of the volume of the inner space 15A of the tubular body 1A.

In the vibration damping structure shown in FIG. 2, the cylindrical molded body 2B is a laminated body in which a cylindrical foamed body 2a and a cylindrical non-foamed polymer body 2b are laminated. The cylindrical foam 2a is in close contact with the inner wall surface of the tubular body 1A in an arbitrary cross section perpendicular to the axis of the tubular body 1A.

In the vibration damping structure shown in FIG. 3, the tubular foam 2C is in close contact with the inside of the tubular body 1B having a square cross section, for example. Cylindrical foam 2C and tubular body 1B
An interface film 4 made of an adhesive, an adhesive, or a plasticizer is provided between the inner wall surface and the inner wall surface.

The cross-sectional shape of the tubular body in the direction perpendicular to the central axis may be a polygon such as a triangle, a quadrangle, a rhombus, or a hexagon, an ellipse, or any other shape. The outer contour and inner contour of the cross section in the direction perpendicular to the central axis of the tubular foam or tubular molded body may also be a quadrangle, a triangle, a rectangle, a rhombus, a hexagon, an ellipse, or any other irregular shape. The tubular body for ensuring the rigidity may be a tubular body made of an inorganic material such as metal, plastic, wood, paper, ceramics, glass or the like, or a composite body thereof, as long as it has adhesion to the tubular molded body. Examples of the metal include steel, aluminum, copper, lead, and alloys.
As plastic, vinyl chloride, polyethylene,
Examples thereof include polypropylene, acrylic, methacrylic and phenol. In addition, as the wood, any wood may be used as long as it has a hollow in the center and has a tubular shape. Examples of the paper include a paper tube and a paper tube impregnated with a resin or the like to give rigidity. Inorganic substances include cement, glass, gypsum,
Examples include pottery, porcelain, and other ceramics.

A suitable volume ratio of the cavity in the inner space of the tubular body is 30 to 80%. When this is 30% or less, the effect of reducing the weight of the vibration damping structure is poor, which is out of the object of the present invention, and the vibration damping characteristics are not improved. Conversely, 80%
In the case of the above porosity, the amount of sound generation during vibration is less reduced, and the sound reduction effect after a certain period of decay is also poor.

4 to 8 are sectional views schematically showing a vibration damping structure according to an embodiment of the present invention. These are used as frames for machines and the like, conveyance paths, vehicles, and structures, and have relatively complicated outer shapes according to their respective applications. Also, in each structure,
In each case, a cavity or an inner space having a shape along the outer shape is provided. This is to reduce the weight of each structure and to waste material. The material of the structure used in each example is the same as that described above as the material of the "tubular body", and specifically, metal, plastic,
Wood, paper, ceramics, glass and composite materials of these. Hereinafter, the damping structure of each drawing will be sequentially described.

First, an example will be described in which a plurality of inner spaces are formed in the structure and one cylindrical molded body is fixed to each inner space (see FIGS. 4 to 6). In the damping structure of FIG. 4, the structure 21A is
Inner spaces 25A and 25B having a substantially rectangular cross section are formed. The size of the inner space 25A is larger than the size of the inner space 25B. The cylindrical molded body 22 is provided inside the inner space 25A.
A is fixed, and the tubular molded body 22B is fixed inside the inner space 25B. The outer peripheral surfaces of the tubular molded bodies 22A and 22B are in close contact with the inner wall surfaces of the inner spaces 25A and 25B.
At the four corners of 22A and 22B, there are some gaps with the inner wall surface. Each hollow portion 23 of each tubular molded body 22A, 22B
The volumes of A and 23B occupy 30% or more and 80% or less of the volumes of the inner spaces 25A and 25B, respectively. In this example, when the tubular molded body 22A is inserted into the inner space 25A,
The cylindrical molded body 22A is once cut and the dimensions are adjusted.
In FIG. 4, 30 indicates this cut portion.

In the damping structure shown in FIG. 5, the structure
21B has a structure in which three tubular portions are connected.
That is, a tubular portion having a circular cross section, a tubular portion having a rectangular cross section, and a tubular portion having a circular cross section are sequentially connected in this order. Then, in the structure 21B, an inner space 25C having a circular cross section is formed.
, And one inner space 25D having a rectangular cross section. A cylindrical molded body 22C is fixed to each inner space 25C, and the outer peripheral surface of each cylindrical molded body 22C is in close contact with the inner wall surface of each inner space 25C over almost the entire surface.

In the inner space 25D, the cylindrical molded body 22D
Has been inserted and fixed. In this example, first, a cylindrical molded product is prepared, the cylindrical molded product is bent as shown in FIG. 5, and is inserted into the inner space 25D in this state.
As a result, the tubular molded body 22D has bent portions 31 formed at two locations. Outer peripheral surface of cylindrical molded body 22D and inner space 25D
However, there is a slight gap between the four corners of the tubular molded body 22D in the width direction and the periphery of the bent portion 31. The volume of each hollow portion 23C of the cylindrical molded body 22C occupies 30% or more and 80% or less of the volume of each inner space 25C. The volume of the hollow portion 23D of the cylindrical molded body 22D occupies 30% or more and 80% or less of the volume of the inner space 25D.

In the damping structure shown in FIG. 6, further,
The structure has elongated through-holes in addition to the above-mentioned inner space, and a solid long molded body made of an organic polymer material is filled in the through-holes. The structure 21C has a complicated shape as shown in FIG. In this structure 21C, there are two inner spaces 25E having a substantially rectangular cross section in the width direction, and two inner spaces 25E.
One F is provided. Around each inner space 25E,
A large number of through holes 26A are provided in each. Each through hole
Each of the 26A has a substantially rectangular shape. Also, each through hole
The size of 26A is designed to be considerably smaller than the size of the inner space 25E. Each inner space 25E is surrounded by a large number of through holes 26A in a single layer.

In each inner space 25E, a cylindrical molded body is formed.
22E is inserted and fixed. The tubular molded body 22F is inserted and fixed in the inner space 25F. Each tubular molded body 22
The volumes of the hollow portions 23E and 23F of E and 22F are 30% or more and 80% or less of the inner spaces 25E and 25F, respectively. Each of the through holes 26A has a solid elongated rectangular rod-shaped foam body 32, respectively.
A is filled.

Next, an example in which a plurality of cylindrical molded bodies are fixed in one inner space will be described. The damping structure of FIGS. 7 and 8 corresponds to this.

The structure 21D shown in FIG. 7 has an elongated complicated cross-sectional shape. The structure 21D is provided with through holes 26B each having a substantially L shape at both ends in the lateral direction. Then, three inner spaces 25G are continuously formed between the pair of through holes 26B. Each inner space 25G has a cross-sectional shape in which a substantially convex shape is turned upside down.
A substantially rectangular inner space 27A is formed between the inner spaces 25G adjacent to each other. Slits 28 are provided in the outer wall on the lower side of each inner space 27A, and each inner space 27A is open to the outside through the slit 28.

Each of the through holes 26B is filled with a solid long molded body 32B made of an organic polymer material.
One tubular molded body 22G is provided in each inner space 25G.
And two tubular molded bodies 22H are inserted and fixed.
The size of each tubular molded body 22H is considerably smaller than the size of the tubular molded body 22G, and between the pair of tubular molded bodies 22H,
The tubular molded body 22G is sandwiched. The total volume of the cavity 23G of the tubular molded body 22G and the volume of each cavity 23H of each tubular molded body 22H occupies 30% or more and 80% or less of the volume of the inner space 25G.

The inner space 27A is formed at a total of two places, and each is sandwiched between two inner spaces 25G. Each one of the cylindrical molded bodies 22I is inserted into each inner space 27A,
Fixed. The volume of the hollow portion 23I of each tubular molded body 22I occupies 30% or more and 80% or less of the volume of the inner space 27A.

The sectional shape of the structure 21E shown in FIG. 8 is substantially rectangular. The structure 21E is provided with an inner space 25H having a cross-sectional shape in which a concave character is turned upside down, and a substantially rectangular inner space 27B is provided in a recessed portion of the inner space 25H. The lower outer wall of the inner space 27B is provided with a slit 29, and the inner space 27B is opened to the outside through the slit 29.

A tubular molded body 22K and two tubular molded bodies 22J are inserted and fixed in the inner space 25H. The dimension of the tubular molded body 22K is slightly smaller than the dimension of the tubular molded body 22J, and between the pair of tubular molded bodies 22J, the tubular molded body
22K is sandwiched. The sum of the volume of the hollow portion 23K of the tubular molded body 22K and the volume of each hollow portion 23J of each tubular molded body 22J occupies 30% or more and 80% or less of the volume of the inner space 25H. The tubular molded body 22L is inserted and fixed in the inner space 27B,
The volume of the hollow portion 23L of the tubular molded body 22L occupies 30% or more and 80% or less of the volume of the inner space 27B. The tubular molded body 22L is largely deformed by the small projections that sandwich the slit 29.

The foam referred to in the present invention is a general term for foams made of an organic polymer material and has an effect as a damping material. The foam preferably used in the present invention,
It can be divided into the following systems. That is, they are (1) rubber type, (2) thermoplastic resin type, and (3) thermosetting resin type. When using these foams, (1) high vibration damping effect.
(2) Deterioration and vibration damping effect do not decrease over a long period of time. (3) Be in close contact with the inner wall of the structure. (4) Do not give adverse effects such as corrosion to the structure. In addition to satisfying the above conditions, it is required to be as light as possible.
However, unlike foams that are generally used in general, many types of durability such as permanent compression strain, oxidation deterioration resistance, and weather resistance under relatively large compressive stress are not required. Therefore, since a foam having no such special durability can be used, it is possible to use a wide range of compositions as described above. On the other hand, on the other hand, in the past, although the damping material itself has a low rigidity, it is used as a material that is more likely to exhibit damping performance. However, this is not always the case, and even a foam exhibiting a high rigidity may be used. The object of the present invention can be sufficiently fulfilled.

As the organic polymer material constituting the tubular foam and the tubular non-foamed polymer in the present invention, many materials can be used alone or in combination depending on the service conditions, and the optimum composition Can be obtained. Specific examples of such organic polymer materials will be shown below.

(1) Rubber type. Rubber-based rubber is roughly classified into natural rubber and synthetic rubber, and synthetic rubber can be further classified into diene-based rubber, non-diene-based rubber, thermoplastic rubber, and liquid rubber. Any of these can be used alone or in combination with the present invention. Natural rubber refers to a substance containing rubber hydrocarbons as a main component, which is collected from plants, and is usually marketed in the form of concentrated latex or raw rubber, and isoprene having cis-1,4 bonds. The diene rubber includes butadiene, styrene-butadiene, chloroprene, butadiene-acrylonitrile, etc., and the non-diene rubber includes isobutylene isoprene, ethylene propylene, chlorosulfonated polyethylene, chlorinated polyethylene, epichlorohydrin type, organosilicon compound type. , Fluorine-containing compound type, urethane type, vinyl type and the like. The thermoplastic rubber is also called a thermoplastic elastomer, and examples thereof include styrene type, olefin type, ester type, urethane type, polyamide type and 1-2 polybutadiene type. Examples of the liquid rubber type include polysulfide rubber type, organic silicon compound type, urethane type, butadiene type, chloroprene type, isoprene type and the like.

In general, the rubber type is preferably adjusted by Mooney viscosity by setting plasticizer, filler and the like and conditions of a kneading machine, rather than using rubber alone. A vulcanization accelerator, a vulcanizing agent, a foaming agent, A foam can be obtained by using a compounding chemical such as a foaming aid and an antiaging agent together.

When the service temperature range is near room temperature, bituminous materials, tackifying resins and other resins and other polymers are used in combination in order to bring the glass transition point of the foam composition close to room temperature. Therefore, it is desirable to further exert the vibration damping effect. In this case, generally, when a resin having a good compatibility is used, the maximum value of the vibration damping property can be taken in a wide temperature range. However, even if a resin with a slightly poor compatibility is mixed,
Although the maximum values are divided into a plurality, the temperature ranges having the maximum values can be brought close to each other by devising the mixing aspect. In this case, the peak value of the vibration damping performance must be sacrificed to some extent, but a foam capable of covering a wider temperature range can be obtained.

(2) Thermoplastic resin system. The thermoplastic resin system is a generic term for plastics that are softened by heating to exhibit plasticity and solidify when cooled. Specific examples are vinyl chloride, vinyl acetate,
Examples include polystyrene, ABS, acrylic, polyethylene, polypropylene, polyamide, acetal, polycarbonate, fibrous plastic, and fluorine resin. The molding cycle is generally shorter than a thermosetting resin described later, and is suitable for mass production. In addition, there is a merit in terms of cost in that scrap generated during molding or the like can be reused. Further, in terms of damping characteristics, a foam having a relatively high rigidity can be used, and if the rigidity is increased, the resonance frequency can be shifted to a high frequency side.

(3) Thermosetting resin system. The thermosetting resin refers to a resin that becomes an insoluble and infusible substance by being cured by heat, a catalyst or a cross-linking agent, and in the present invention, a resin that undergoes a chemical reaction with a cross-linking agent and cures even without heat or a catalyst Also included. Specific examples thereof include phenol resin, urea resin, melamine resin, unsaturated polyester resin, epoxy resin, diallyl phthalate resin, polyurethane resin, silicon resin and polyimide resin.

Many of these have relatively low molecular weights and are suitable for simultaneously foam-molding into a tubular body. These include those that are rich in rubber elasticity such as polyurethane resin and silicon resin, and those that have relatively high rigidity such as phenol resin, unsaturated polyester resin and epoxy resin. Select a more suitable polymer considering the vibration characteristics of the tubular body,
By using a plasticizer, a filler, a bituminous substance, another type of polymer in combination, and adjusting the molar ratio of the cross-linking agent, the damping effect can be further exerted.

Next, materials that can be added to the above organic polymer materials to adjust the vibration damping property, stabilize the molding operation, adjust the foaming degree, etc. will be described. The plasticizer plays a role of a lubricant between polymers, assists in fluidity between molecules, reduces intermolecular internal friction, and adjusts the plasticity suitable for molding a foam.

Specific examples thereof include petroleum softeners such as naphthene oils, aromatic oils and paraffin oils, castor oil, soybean oil, animal and vegetable oils such as pine tar, phthalic acid such as DBP and DOP. Ester type, D
Aliphatic dibasic acid ester type composed of OA, DBS, etc., T
Trimellitic acid ester type composed of OTM, TDTM, etc., epoxidized fatty acid monoester, epoxy type composed of epoxidized linseed oil, etc., phosphoric acid ester type composed of TCP, TOP, etc., dibutyl carbitol adipate, triethylene glycol di-2 -Ethyl butyrate, etc. ether type, adipic acid polyester, azelaic acid polyester, etc. polyester type, chlorinated fatty acid ester, chlorinated paraffin, etc. Rubber can be used alone or in combination as a plasticizer. In addition,
The inventor has discovered new uses for such plasticizers. This will be described later.

Next, as the filler, vibration damping property, specific gravity,
It is effective for weight reduction, thermal conductivity, anticorrosion, and flame retardancy, and those generally used in the rubber and coating industry can be used. Specific examples thereof include mica, graphite, leucite, talc, scale-like inorganic powder such as clay, ferrite, zinc white, iron oxide, metal powder, barium sulfate, high specific gravity and thermal conductive filler such as lithopone, carbonic acid. General-purpose fillers such as calcium, finely divided silica, carbon, magnesium carbonate,
Flame retardant improvers such as antimony trioxide, borax, aluminum hydroxide, glass hollow powder, perlite, resin foam powder, rubber foam powder, resin powder, rubber powder, fiber powder,
The purpose can also be achieved by adding a lightweight filler such as paper powder.

Next, the tackifying resin has an effect of adhering to the inner wall of the tubular body and an effect of improving the vibration damping property, and specific examples thereof include natural resin, rosin, modified rosin, rosin and derivatives of modified rosin, and polyterpene resin. , Modified terpene, aliphatic hydrocarbon resin, cyclopentadiene resin,
Aromatic petroleum resins, phenol resins, alkylphenol-acetylene resins, xylene resins, coumarone-indene resins, vinyltoluene-α-methylstyrene copolymers and the like can be used alone or in combination.

Next, the bituminous material has an effect of adhering to the inner surface of the tubular body and an effect of improving the vibration damping property, and specific examples thereof include straight asphalt, blown asphalt, tar and pitch. Other compounding agents include rust preventives, antioxidants, vulcanizing agents, catalysts and surfactants.

The foaming agent and the foaming auxiliary agent are decomposed mainly by heating the compound to generate a gas such as carbon dioxide gas, nitrogen gas, ammonia, etc. to give the organic polymer material a cell structure. It is a thing. The specific example is as follows. Sodium bicarbonate, ammonium bicarbonate,
Inorganic foaming agents such as ammonium carbonate, nitroso compounds such as N, N'-dinitroso pentamethylene tetramine, azo compounds such as azodicarbonamide, azobis isobutyronitrile and barium azodicarboxylate. , Benzene sulfonyl hydrazide,
There are sulfonyl hydrazide type foaming agents such as P, P'-oxybis (benzenesulfonyl hydrazide) and toluene sulfonyl hydrazide, which can be used alone or in combination. Further, it is possible to set more suitable conditions by adjusting the gas release rate and the decomposition temperature in combination with a foaming auxiliary agent described later.

As the foaming aid, salicylic acid, urea, urea derivatives and the like can be used. In addition, when the compounded composition is a liquid, a foaming reaction can be stabilized by using a foaming agent such as a surfactant, a foam stabilizer such as a silicone-based foam stabilizer, and a foam stabilizer.

As the cross-linking agent, it is necessary to use the cross-linking agent most effective for the organic polymer material as the base. In general, sulfur and organic peroxides are used for the rubber type, but for the rubbers or resins shown in Tables 1 and 2, the following crosslinking agents can be used in addition to the above. However, in Table 1, the organic polymer material and the cross-linking agent are shown by general names, and in Table 2, they are shown by the kinds of functional groups.

[0044]

[Table 1]

[0045]

[Table 2]

In crosslinking, many kinds of compounds can be used together as a crosslinking accelerator. In the present invention, it is only necessary to consider whether or not to cause discoloration in the case where the tubular body is made of a polymer material, and other factors mainly include the decomposition rate of the foaming agent and the crosslinking rate. The optimum amount may be determined in consideration of the balance. Further, it is not necessary to use a crosslinking accelerator for all polymers, and it is sufficient to use it when absolutely necessary.

There are the following methods for manufacturing the damping structure of the present invention. First, the first method will be described with reference to FIGS. 9 (a) and 9 (b). A tubular body 1A shown in FIG. 9 (a) is prepared. Further, the cylindrical molded product 5A shown in FIG. 9 (b) is manufactured from an organic polymer material. At this time, when the diameter W1 of the inner space of the tubular body 1A is 100, the outer dimension W2 of the cylindrical molded product 5A is 100 to 140. This cylindrical molded product 5
A is compressed and inserted into the inner space of the tubular body 1A, and the tubular body 1A is compressed by the restoring force of the cylindrical molded body fixed in the inner space.
The cylindrical molded body is brought into close contact with the inner wall surface of the.

When the inner diameter W1 of the tubular body 1A is 100, the outer diameter W2 of the cylindrical molded product 5A is 100-14.
Must be 0. That is, the outer diameter W of the cylindrical molded product
If 2 is less than 100, from the viewpoint of long-term durability, the adhesion between the cylindrical molded body and the tubular inner wall tends to be poor, and the vibration damping effect tends to deteriorate accordingly.
Not preferred. On the contrary, the outer diameter W2 of the cylindrical molded product is 14
If it is larger than 0, from the viewpoint of long-term durability, like the case where it is smaller, the adhesiveness tends to deteriorate due to the influence of compression set, and the damping effect also deteriorates accordingly, which is not preferable.

Even when the cross-sectional shape of the tubular body or the tubular molded article is not annular, the inner shape of the tubular body may be similar to the outer shape of the tubular molded article. Also in this case, the dimension of the outer contour of the tubular molded product is 100 to 140 when the dimension of the inner contour of the tubular body is 100.

In the method described here, it is preferable to apply an adhesive, an adhesive or a plasticizer to the surface of the tubular molded product before inserting the tubular molded product into the inner space of the tubular body. As the plasticizer, those mentioned above can be diverted. By applying the plasticizer as described above, when the tubular molded article is inserted into the inner space of the tubular body, it has a lubricating action and is easy to insert. In addition, after the insertion of the tubular molded product, the plasticizer is absorbed by the surface of the tubular molded product, and the vicinity of this surface swells, so that the adhesion between the tubular molded product and the tubular inner wall is reduced. It was found that the vibration damping characteristics were further improved. When a plasticizer is used for this purpose, if a solvent, a tackifying resin or the like is added to the plasticizer, the plasticizer easily penetrates into the surface of the tubular molded body.

As the pressure-sensitive adhesive and the adhesive, those generally used can be used. Then, by applying a pressure-sensitive adhesive or an adhesive to the surface of the tubular molded product to insert the tubular molded product into the inner space of the tubular body, there is a lubricating action and it is easy to insert. Further, the adhesion to the tubular body is further improved after inserting the tubular molded product. Adhesive,
When a water-based adhesive is used as the adhesive and a metallic one is used as the tubular body, it is preferable to add a rust preventive to the pressure-sensitive adhesive and the adhesive.

When the adhesive or the adhesive contains water or a solvent, it is preferable to provide a plurality of elongated projections on the surface of the cylindrical molded product. FIG. 10 is a sectional view showing such a cylindrical molded product 5B. In the cylindrical molded product 5B of this example, a large number of elongated protrusions 6 are provided on the surface in the axial direction, and elongated protrusions 14 are formed between the protrusions 6. When the cylindrical molded product 5B is inserted into the inner space of the tubular body 1A, the recess 14 serves as a passageway for water and solvent, and even after the insertion, bubbles are less likely to be contained between the cylindrical molded body and the tubular body.

Besides, the following manufacturing method can be considered. (a) A rod or pipe which has been subjected to a mold release treatment in advance is installed in the inner space of the structure, a liquid material is injected into the inner space, foamed and cured, and then the rod or pipe is extracted from the inner space. (b) A liquid material is injected into the inner space of the structure, and the liquid material is foamed and cured while rotating the structure to form a tubular foam. (c) A material for foam molding is injected into the extruder, and the foam material is extruded while moving the nozzle of the extruder in the inner space of the structure to perform foam molding.

Specific experimental results will be described below. (Preparation of formulations). Formulations having the following composition ratios were prepared.

[0055]

[Table 3]

[0056]

[Table 4]

[0057]

[Table 5]

[0058]

[Table 6]

(Production of damping structure). As the tubular body 1A, a 100A steel pipe having a plate thickness of 2.3 mm and a length of 500 mm was used. In Examples 1 and 2 and Comparative Examples 2 and 3, tubular composites having the structure shown in FIG. 2 were manufactured. However, the material of the cylindrical foamed body 2a was the above-mentioned "blend A1", and the material of the cylindrical non-foamed body 2b was the above-mentioned "blend A2". First, a cylindrical molded product made of a cylindrical foamed body and a cylindrical non-foamed body was manufactured, and this was inserted into the inner space of the tubular body 1A. At this time, the size of the outer diameter of the cylindrical molded product when the inner diameter W1 of the tubular body 1A was 100 was changed as shown in Table 1. Further, in Example 2 and Comparative Example 2, process oil as a plasticizer was applied to the outer surface of the cylindrical molded product.

In Example 3, a tubular composite having the structure shown in FIG. 1 was manufactured. That is, a cylindrical molded product (foam) was produced using the above-mentioned "blend B", solvent-based butyl glue was applied to the outer surface of the molded product, and the product was inserted into the inner space of the tubular body 1A. In Examples 4 and 5, tubular composites having the structure shown in FIG. 1 were produced. That is, the above-mentioned compound C is contained in the tubular body 1A.
Was injected, and the formulation C was cured while rotating the tubular body 1A. In Comparative Example 1, the tubular body 1 shown in FIG.
A was used alone.

The following characteristics were measured for each example. (Porosity). The porosity (%) was calculated from the following formula. Porosity (%) = (volume of inner space of tubular body 1A-volume of cylindrical molded body) × 100 / volume of inner space of tubular body 1A.

(Vibration damping performance). The measurement was performed using a measuring device schematically shown in FIG. The hanging thread 8 was applied to the fulcrum 7, and two specimens 9 were hung. A microphone 10 is installed on the extension of the center axis of the test piece 9, and the microphone 10, sound level meter 11, frequency analyzer 1 are installed.
2. Recorder 13 was connected in order. The height of the microphone 10 was 1.2 m from the ground, the distance between the microphone 10 and the sample 9 was 1 m, and the vibration point of the sample 9 was at the center of the sample 9. The time from vibration to 20 dB noise reduction was measured and displayed as "vibration damping performance (ms)".

(Radiation peak sound due to impact). Sound pressure level (dB) under the same measurement condition as the item of "Vibration damping performance"
The peak value of was measured and displayed. (Adhesion). After the acoustic measurement was completed, accelerated deterioration was performed at 70 ° C. for 7 days, and it was checked whether or not the cylindrical molded body could be easily taken out from the test piece. Those that could not be easily taken out were marked with "○", those that could be taken out easily were marked with "×",
The results are shown in Table 7.

[0064]

[Table 7]

In Example 1, the vibration damping performance is also "55".
ms "and the emission peak sound is also compared to the case of a single pipe.
It has been reduced by more than 20 dB. It also has good adhesion and can withstand long-term use. The tubular composite of Example 2 has the same structure as that of Example 1. However, the outer diameter of the cylindrical molded product before insertion was made larger than that in Example 1, a plasticizer was used, and the porosity was made smaller. The damping performance is
Even better than the tubular composite of Example 1.

In Example 3, compared with Comparative Example 1 (example of a single tube), the vibration damping time was shortened to about 1/3 and the radiated peak sound was also improved by 16 dB. Adhesion was also good, and there was no effect of accelerated deterioration. In Examples 4 and 5,
It is an example in which a thermosetting resin is simultaneously molded in a tubular body. It can be seen that the damping performance is good and the emission peak sound is slightly higher than that of the third embodiment, but the damping time is very short. The adhesion was very good.

Comparative Example 1 is an example in which the tubular body 1A was used alone. The vibration damping performance is significantly inferior to that of the present invention. Comparative Examples 2 and 3 showed the structurally same tubular composites as Examples 1 and 2. In Comparative Example 2, the porosity is 26% and the outer diameter of the cylindrical molded product is 95. In this case, even when the solvent-based butyl glue was applied, insufficient adhesion was still generated, the emission peak sound was increased, the decay time was extended, and the noise continued for a long time.

In Comparative Example 3, the porosity is 85% and the outer diameter of the cylindrical molded product is 145. In this case, it became difficult to insert the cylindrical molded article into the tubular body. The radiated peak sound was considerably louder than that in Example 1, and the vibration damping performance was also poor.

(Production of Damping Structure) A damping structure shown in FIG. 8 was manufactured. The material of the cylindrical molded bodies 22J and 22K was the above-mentioned "compound A1". First, manufacture a cylindrical foam product,
This was inserted into the inner space 25H. No plasticizer was applied to the cylindrical foam.

For each example, the "vibration damping performance", "radiation peak sound due to impact" and "adhesion" were measured as described above. The porosity (%) was calculated from the following formula. Porosity (%) = (volume of inner space 25H-cylindrical molded body 22
Total volume of J and 22K) x 100 / volume of inner space 25H.

[0071]

[Table 8]

As can be seen from Table 8, when the porosity is 30 to 80%, the vibration damping performance is improved and the noise is reduced. This was also verified in the modified damping structure shown in FIG.

[0073]

As described above, according to the vibration damping structure of the present invention, the amount of sound generated when a shock is applied is reduced, the damping speed when a shock is applied is increased, and the noise reduction effect is achieved. Very expensive. Moreover, since 30% to 80% of the volume of the inner space of the structure is made hollow and at least a part of the cylindrical molded body is made of foam, the weight of the vibration damping structure can be made extremely small. It was

As a result, in the power member, it is possible to reduce the loss of power and noise at the time of power transmission, and it is possible to pass the rotary shaft through the hollow portion of the tubular molded body. . Also, structural members can be applied to many applications by reducing the weight of the structure, downsizing the substructure, reducing transport loss, and reducing the material cost required for noise prevention measures by using foam. It is possible and the merits are great. The present invention has extremely high industrial utility value in preventing noise and vibration and providing a comfortable space.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a damping structure according to an exemplary embodiment of the present invention, taken in a direction perpendicular to its axial direction.

FIG. 2 is a cross-sectional view of the vibration damping structure according to the embodiment of the present invention, taken in a direction perpendicular to the axial direction thereof.

FIG. 3 is a cross-sectional view of the vibration damping structure according to the embodiment of the present invention, taken in a direction perpendicular to the axial direction thereof.

FIG. 4 is a sectional view schematically showing an example in which the present invention is applied to a structure 21A.

FIG. 5 is a sectional view schematically showing an example in which the present invention is applied to a structure 21B.

FIG. 6 is a sectional view schematically showing an example in which the present invention is applied to a structure 21C.

FIG. 7 is a sectional view schematically showing an example in which the present invention is applied to a structure 21D.

FIG. 8 is a sectional view schematically showing an example in which the present invention is applied to a structure 21E.

9A is a cross-sectional view of the tubular body 1A taken along a direction perpendicular to its axis, and FIG. 9B is a cross-sectional view of the cylindrical molded article 5A taken along a direction perpendicular to its axis. It is a figure.

FIG. 10 is a cross-sectional view showing a cylindrical molded product 5B before being inserted into the inner space of the tubular body 1A.

FIG. 11 is a schematic view showing an apparatus for measuring the vibration absorption characteristics of the vibration damping structure.

[Explanation of symbols]

1A, 1B, 21A, 21B Tubular body (an example of a structure) 2A, 22C Cylindrical foam (an example of a cylindrical molded body) 2B Cylindrical foam of a two-layer structure 2C Cylindrical foam (of a cylindrical molded body) Example) 2a Cylindrical foam 2b Cylindrical non-foam 3A Cavity 4 Interface film made of plasticizer, adhesive or adhesive 5A, 5B Cylindrical molded product before insertion 6 Elongated projections 14 Elongated recesses 21A, 21B, 21C, 21D, 21E, 1A, 1B structure 22A, 22B, 22D, 22E, 22F, 22G, 22H, 22I, 22
J, 22K, 22L Cylindrical compact 23A, 23B, 23C, 23D, 23E, 23F, 23G, 23H, 23
I, 23J, 23K, 23L cavity 25A, 25B, 25C, 25D, 25E, 25F, 25G, 25H, 15
A, 15B Inner space 26A, 26B Through hole 27A, 27B Slit inner space 28, 29 Slit

Claims (8)

[Claims] 1. A vibration control structure for suppressing vibration of a structure having an elongated inner space due to a shock applied from the outside thereof, the structure being provided in the structure and an inner space of the structure. A tubular molded body made of an organic polymer material, and a hollow portion is provided inside the tubular molded body, and the tubular molded body contains at least a tubular foamed body. And the outer peripheral surface of the tubular foam is in close contact with at least a part of the inner wall surface of the structural body in an arbitrary cross section perpendicular to the axis of the structural body, and the hollow portion of the tubular molded body. The surface on the side is exposed to the cavity without being restrained, and the volume of the cavity is smaller than the volume of the inner space of the structure.
A vibration control structure characterized by occupying 30% or more and 80% or less. 2. A laminate of a tubular foam body in which the tubular molded body is in close contact with the structural body, and a tubular non-foamed polymer body formed inside the tubular foam body. The vibration damping structure according to claim 1, wherein 3. The vibration damping structure according to claim 1, wherein the tubular molded body is made of the tubular foam. 4. The vibration damping structure according to claim 1, wherein the structure is a tubular body having one inner space, and one cylindrical molded body is fixed to the inner space. 5. The vibration damping structure according to claim 1, wherein a plurality of the inner spaces are formed in the structure, and each of the tubular molded bodies is fixed to each of the inner spaces. 6. The vibration damping structure according to claim 1, wherein a plurality of the cylindrical molded bodies are fixed in one inner space. 7. The structure has an elongated through hole separately from the inner space, and a solid elongated molded body made of an organic polymer material is filled in the through hole. Or the vibration control structure described in 6. 8. A slit is provided on an outer wall of the structure, and the inner space communicates with the slit.
The vibration damping structure according to claim 1.