JP2002250397A - Vibration-proof material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vibration-proof material enhanced in damping property. SOLUTION: This vibration isolating material includes a viscoelastic material and has a sandwich structure in which a high specific gravity member is arranged in a wave form between low specific gravity members in the input direction of vibration.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a high vibration damping property (vibration damping property) and can be applied to precision equipment, audio equipment, information equipment, video equipment, etc., which maintain high vibration damping properties even when temperature changes. Regarding vibration material.

[0002]

2. Description of the Related Art In general, the vibration damping properties of a vibration damping material used for a hard disk of a computer, a home electric appliance, a general machine, as well as a wind power generator, etc., are almost always determined by the material characteristics itself, regardless of the application. . For example, as a vibration isolator for computer equipment, a low-rebound resilience rubber composition prepared by adding polynorbornene as a main material and adding a filler such as carbon black and silica and a softening agent such as oil is used. In general household electrical appliances and general machinery, a low-rebound rubber composition prepared similarly using butyl rubber as a main material is used.

[0003] These rubber compositions have a high loss factor (ta).
nδ), and exhibits good anti-vibration performance near room temperature. However, since the temperature dependency is large, the vibration isolation performance in a temperature region other than the room temperature region is reduced.

For example, a norbornene polymer generally used has a characteristic of a damping characteristic represented by a vibration transmissibility and a loss coefficient with respect to a vibration of a device to be damped, and has a high peak value in a normal temperature range. In a low temperature range of 0 ° C. or lower, the loss coefficient decreases and the damping property decreases. On the other hand, even in a high temperature region of 50 ° C. or higher, the loss coefficient decreases, and the attenuation rate decreases. Therefore, the temperature range (−10 ° C.) under the normal use environment of the vibration isolating material
(.About.60.degree. C.), the attenuation characteristics vary greatly with temperature. For this reason, there is a problem that the use becomes difficult unless the temperature in the use environment is adjusted.

In order to reduce the temperature dependency of the vibration isolation,
As a conventionally known technique, Japanese Patent Application Laid-Open No. 11-199744 has proposed a mixed system of a functional group-containing acrylic rubber and a halogenated butyl rubber. However, such technology cannot sufficiently reduce the temperature dependency in both the low-temperature region and the high-temperature region.

The present inventor has disclosed a prior application (Japanese Patent Application No. 2000-2).
In the invention according to No. 53711), by using a sandwich structure in which a high specific gravity material is sandwiched in the center of the existing vibration damping material, the vibration damping effect of the existing vibration damping material when the structure is subjected to compression and tension vibrations In addition, since the high specific gravity material placed in the center vibrates differently from the surrounding low specific gravity existing material, a damping effect is added due to the phase difference there, and the damping performance is improved in a wide temperature range. I found it to be realizable. However, although the vibration damping property is improved by such a vibration damping material, the loss coefficient (ta)
There is still a demand for providing a vibration-proofing material with further increased nδ) and further enhanced vibration damping.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a vibration damping material having further improved damping performance.

[0008]

According to the present invention, there is provided a vibration isolator including a viscoelastic material, wherein the vibration isolator is provided by laminating a high specific gravity material between low specific gravity materials in a vibration input direction. It is characterized by having a sandwich structure formed.

[0009] The corrugation of the high-specific-gravity material is preferably 0,1.
2 ≦ W / L ≦ 1, more preferably 0.3 ≦ W / L
≦ 1.

The specific gravity of the high specific gravity material is preferably at least five times the specific gravity of the low specific gravity material.

Further, the ratio of the thickness of the high specific gravity material to the total thickness of the vibration isolator is preferably set in a range of 0.05 to 0.5.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention is typically shown in FIG. 1 in a front view with a vibration isolator 1 inserted between upper and lower rigid plates 2.

In FIG. 1, the vibration isolator 1 is a sandwich in which a viscoelastic material such as a rubber composition corrugated as a high specific gravity material 3 is disposed in the center, and a viscoelastic material is disposed above and below the low specific gravity material 4. It has a structure. Then, the vibration is input from the direction of arrow F.

[0014] By laminating the high specific gravity material in the center of the existing vibration damping material, the high specific gravity material in the central portion vibrates differently from the surrounding low specific gravity material, in addition to the vibration damping effect of the existing material. Therefore, a phase difference occurs there and an attenuation effect is added, but in the present invention, by making the shape of the high specific gravity material in the central portion into a waveform, an interference effect based on the wave shape is added, and a flat high specific gravity material is used. The damping effect can be further improved as compared with the case where it is provided.

In order to exhibit the effect of the present invention, as shown in FIG. 1, the waveform of the high specific gravity material provided at the center of the vibration isolator has an average of the distances (wavelengths) between adjacent peaks. Where L is the average and the average of the fluctuations (lengths) from adjacent peaks to valleys is W, it is preferable to set the range of 0.2 ≦ W / L ≦ 1. More preferably, it is set in the range of 0.3 ≦ W / L ≦ 1.

If W / L is smaller than 0.2, the wave shape becomes small and the difference from the flat plate becomes small, so that the attenuation performance is not improved. On the other hand, if W / L is larger than 1, the adjacent waves are too close to each other, so that the waves do not have a wave shape and a thick flat plate is sandwiched, so that no interference effect occurs and the volume of the high specific gravity material is low. It becomes relatively large compared to the specific gravity material, and the damping performance of the structure is dominated by the characteristics of the high specific gravity material. As a result, the damping effect of the low specific gravity material cannot be obtained, and the damping performance of the vibration isolator decreases. I do.

The high specific gravity or the low specific gravity means a relative relationship. In order to exhibit the effects of the present invention, it is preferable that the specific gravity of the low specific gravity material is set in a range of about 1 to 2 g / cm ³ . On the other hand, a high specific gravity material has a specific gravity of 3 to 2
0 g / cm ^3, preferably 5 to 20 g / cm ^3, especially 9
It is set in the range of 20 g / cm ³ . Then, the ratio (S1) between the specific gravity of the high specific gravity material (S1) and the specific gravity of the low specific gravity material (S2)
/ S2) is at least 5, preferably at least 9. When the specific gravity ratio (S1 / S2) is smaller than 5, the specific gravity difference between the high specific gravity material and the low specific gravity material becomes too small,
The force generated by the high specific gravity material vibrating inside the structure is not sufficiently applied, and as a result, improvement in damping performance cannot be expected.

In order to exhibit the effect of the present invention, it is preferable that the thickness T1 of the high specific gravity material is set in the range of 0.05 ≦ T1 / T0 ≦ 0.5 with respect to the total thickness T0. More preferably, it is set in the range of 0.1 ≦ T1 / T0 ≦ 0.3.

That is, if T1 / T0 is less than 0.05, the improvement ratio of the damping performance by the high specific gravity material becomes small,
It is not so effective. Conversely, if it exceeds 0.5, the ratio of the high specific gravity material becomes too large, so the damping performance of the structure is governed by the characteristics of the high specific gravity material, and the damping performance by the low specific gravity viscoelastic material Decrease. Further, when a viscoelastic material such as rubber is used as the high specific gravity material, the hardness of the high specific gravity material itself is considerably higher than that of the conventional rubber composition due to the metal powder blended to adjust to a high specific gravity. Therefore, when the ratio of T1 / T0 exceeds 0.5, the hardness of the high specific gravity material becomes too large, and the elasticity of the structure is increased. The vibration isolator according to the present invention does not vibrate effectively, and the damping performance is not sufficiently exhibited.

Since the effect of the present invention is achieved by the interference effect based on the fact that the high specific gravity material has a wave shape, the waveform of the high specific gravity material provided at the center portion does not necessarily have to have a uniform thickness. Can be considered as the thickness of the thickest part of the high specific gravity material.

The material having a high specific gravity is not particularly limited to the type of the material. In addition to a metal plate, a plastic, a rigid plate, and a viscoelastic material such as rubber, a metal powder having a generally high specific gravity such as tungsten or lead is kneaded. Can be used. The performance is not affected by the adhesion between the layers of the high specific gravity material and the low specific gravity material.However, considering the problems in management and use, metal powder is used for the conventional viscoelastic material, that is, the vibration-proof rubber material. It is desirable to use a composition prepared and adjusted for specific gravity, and integrally vulcanize it as a laminated structure with a conventional anti-vibration material.

In the present invention, the high specific gravity material and the low specific gravity material are not particularly limited as long as they have a damping property, but it is preferable to use a viscoelastic material for both. For example, a norbornene-based polymer, natural rubber, styrene-butadiene rubber, isoprene rubber, butadiene rubber, chloroprene rubber, nitrile rubber, ethylene-propylene copolymer rubber, butyl-based rubber, IIR-based rubber, EPDM, or the like may be used alone or as a mixture. It can be used as a composition having damping properties.

Particularly, in the present invention, a rubber composition containing a norbornene-based polymer or an IIR-based rubber as a main component can be suitably used. When using a norbornene-based polymer,
For example, the monomer is a ring-opened polymer or copolymer of bicyclo (2,2,1) heptene-2 or a derivative thereof. For example, as the monomer to be used, bicyclo (2,2,1) heptene-2, alkyl-5-bicyclo (2,2,1) heptene-2 monomer, alkoxy-5
-Bicyclo (2,2,1) heptene-2 monomer, bicyclo (2,2,1) heptene-2-5,6 dicarboxylic acid diester monomer, and mixtures thereof can be used.

As the high specific gravity inorganic filler used in the viscoelastic material composition of the present invention, a metal oxide such as beryllium,
Group II metal elements such as magnesium, zinc and calcium; group IV metal elements such as titanium, tin, zirconium and lead; group V metal elements such as antimony and vanadium;
Group VI metal elements such as chromium, molybdenum, and tungsten, and oxides of group VIII metal elements such as iron, cobalt, and nickel can be used.

The amount of the inorganic filler is, for example, 200 to 1700 parts by weight per 100 parts by weight of the viscoelastic material (rubber) in the case of butyl rubber. If the amount is less than 200 parts by weight, a composition having a predetermined high specific gravity cannot be obtained, and the vibration-proof effect is small. If it exceeds 1700 parts by weight, the strength is greatly reduced and mixing becomes difficult.

Next, the viscoelastic material composition of the present invention is compounded and designed so as to have a predetermined damping property, and vulcanizing agents, antioxidants, carbon black, silica, etc. which are usually used in the rubber industry. , A filler such as calcium carbonate, and other compounding agents are appropriately compounded.

The viscoelastic material composition of the present invention usually contains 1
Vulcanization is carried out at a temperature in the range of 40 ° C to 200 ° C for about 1 to 120 minutes.

As shown in FIG. 1, the high specific gravity material of the present invention exhibits sufficient damping performance even when it is formed as a single layer. However, it can be formed as a multilayer having two or more layers. The vibration damping effect is exhibited by the same principle as in the case.
That is, the effect of the present invention is exhibited without being limited to the number of layers of the high specific gravity material.

[0029]

EXAMPLE A vibration isolator according to an example of the present invention was manufactured with the structure shown in FIG. 1 and the specifications of a high specific gravity material and a low specific gravity material as shown in Tables 1 and 2. FIG. 2 shows a vibration damping material of a comparative example.
The structure shown in FIG. 3 and FIG. 4 was manufactured according to the specifications shown in Tables 1 and 2.

The dimensions of the vibration-proof material were 29 mm in outer diameter and 12 mm in total thickness in both the examples and comparative examples.

Next, in order to evaluate the vibration-damping effect of the vibration-damping material, a square iron plate having a length of 45 mm and a width of 7.5 mm and a thickness of 7.5 mm was arranged above and below the vibration-damping material, and a hydropulse dynamic tester (Tokyo Ikki Manufacturing Co., Ltd.) Was measured under the following conditions.

Load cell capacity (Max): 1.5 tons Initial strain: 2 mm The initial strain is 2 mm with respect to the total thickness of the vibration-proof material of 12 mm.
Vibration was performed after the compressive strain was given in advance.

Amplitude: ± 1 mm Frequency: 20 Hz Measurement temperature: 0 ° C. to 40 ° C.

[0034]

[Table 1]

Note 1) Bromobutyl 225 manufactured by Exxon
5 was used. Note 2) Diamond Black H manufactured by Mitsubishi Kasei Co., Ltd. was used as the carbon black HAF.

Note 3) Noxeller D manufactured by Ouchi Shinko Chemical Co., Ltd.
Z (N, N'-dicyclohexyl-2-benzothiazoylsulfenamide) was used.

[0037]

[Table 2]

From the measurement results shown in Table 2, the loss coefficient of Example 1 of the present invention was higher than that of Comparative Examples 1 to 3, and it was confirmed that the vibration isolation was improved. .
In addition, the loss tangent (tan δ) is increased from 1.20 to 1.31 (an increase of 9% or more) by changing the sandwiched high specific gravity material from a flat plate (Comparative Example 2) to a waveform (Example 1), and the damping performance is improved. Improved.

The embodiments and examples disclosed this time are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

[0040]

As described above, the present invention uses a corrugated high-specific-gravity material for a part of the laminated body of the vibration-proof material, so that a new vibration source is added in addition to the vibration-damping characteristics of the conventional vibration-proof material. Thereby, the damping effect is enhanced and the vibration isolation is further improved.

[Brief description of the drawings]

FIG. 1 is a front view showing a state in which rigid plates are arranged above and below a vibration isolator according to the present invention.

FIG. 2 is a front view showing a state in which rigid plates are arranged above and below a conventional vibration isolator made only of a low specific gravity material 5;

FIG. 3 is a front view showing a state in which rigid plates are arranged above and below a vibration isolator in which a plate-shaped high specific gravity material 7 is arranged between low specific gravity materials 6;

FIG. 4 shows a horizontal 2.5c above and below a flat high specific gravity material 9
FIG. 2 is a front view of a state in which strip-shaped high specific gravity materials 10 of mx 2.5 cm in height are arranged at regular intervals, and rigid plates are arranged above and below a vibration isolator in which these are laminated between low specific gravity materials 8. .

[Explanation of symbols]

1 Anti-vibration material, 2 Rigid plate, 3 High specific gravity material, 4 Low specific gravity material, 10 Rectangular high specific gravity material.

Claims (6)

[Claims] 1. A vibration damping material including a viscoelastic material, wherein the vibration damping material has a sandwich structure in which a high specific gravity material is arranged in a wave form between low specific gravity materials in a vibration input direction. Anti-vibration material. 2. The waveform of a high-specific-gravity material is defined as follows: L is the average of the distance (wavelength) between adjacent peaks, and W is the average of the variation (length) from the adjacent peak to valley. 2 ≦ W / L
The vibration damping material according to claim 1, wherein ≤1. 3. The waveform of the high specific gravity material is 0.3 ≦ W / L ≦
2. The vibration damping material according to claim 1, wherein 4. The vibration damping material according to claim 1, wherein the specific gravity of the high specific gravity material is at least five times the specific gravity of the low specific gravity material. 5. The vibration damping material according to claim 1, wherein a ratio of a thickness of the high specific gravity material to a total thickness of the vibration damping material is in a range of 0.05 to 0.5. 6. The vibration damping material according to claim 1, wherein the low specific gravity material is a viscoelastic material.