JP2000213591A - Vibration damping panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain excellent vibration damping performance in a large range of vibrating conditions by filling high rigidity grains with the surfaces coated with low elastic material, between two plates opposed to each other with a space. SOLUTION: A vibration damping panel 1 is formed by high rigidity grains 7 (coated grains 8a) with the surfaces coated with low elastic material 6, in a space 5 between two plates 2, 2 opposed to each other with a space. The space 5 between two plates 2, 2 is preferably divided by partitions 4, and the high rigidity grains 7 are filled in the divided spaces 5 to form a grain layer 8. When the panel 1 is vibrated, an energy absorbing phenomenon is induced by friction between the partitions 4 and the coated grains 8a to obtain excellent vibration damping performance. As the low elastic material 6, material with Young's modulus smaller than 106 N/m2, that is, rubber material such as synthetic rubber or natural rubber is used, and the material density of the high rigidity grains 7 is adjusted into a range of 1000-2000 kg/m3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a damping panel having high damping performance.

[0002]

2. Description of the Related Art In recent years, high performance such as high speed and high output of transport machines such as automobiles, railways and aircrafts, industrial machines and home electric appliances has been promoted, and at the same time, small and thin designs have been actively pursued. Is being done. Along with this, the vibrations generated from various machines and equipment, and the accompanying noises become very problematic.

As one of the prior arts for solving these vibration and noise problems, there is a vibration damping panel 1 'shown in FIG. This is characterized in that two plate members 2 arranged opposite to each other at a certain interval, and a granular material 3 is filled between the two plate members 2 (for example, Japanese Patent Application No. Sho 62). -9
No. 4329, Japanese Patent Application No. 2-179738).

Here, as an index indicating the vibration damping performance of the vibration damping panel 1 ', there is a loss coefficient. Generally, when this value is 0.1 or more, it is evaluated that the vibration damping performance is high.
FIG. 14 shows an apparatus for measuring a loss coefficient. This is a beam 51 partitioned into ten spaces that can be filled with the granular material 3.
Of the vibrator 5 via the impedance head 56
Fix to 3. Then, random noise having a specific range of frequency components generated by the signal generator of the FFT 54 is input to the amplifier 55, and the vibrator 53 randomly vibrates in the vertical direction. Further, acceleration and force are sensed by the impedance head 56 at the center of the beam 51 and input to the FFT 54 via the amplifier 57. And FFT
54, a transmission characteristic such as inertance (acceleration / force) and an apparent mass (force / acceleration) is measured, and a loss coefficient is extracted from peaks and valleys due to resonance or anti-resonance shown in the transmission characteristics. .

Next, the damping performance of the damping panel filled with the granular material 3 will be described.

FIG. 15 shows a loss coefficient when the value of the vibration acceleration level La received by the panel is changed from 100 to 140 dB. Here, the value of the vibration acceleration level La is represented by La = 20 log (a / a ₀ ) [dB].

In this equation, a is the effective value of the measured acceleration (m / s ² ), and _ao is the reference acceleration defined by the JIS standard, and its value is 10 ⁻⁵ m / s ² . . For example, when La is 120 dB, a is about 1 G (G = 9.
817 m / s ² ).

The curve (A) shown in FIG.
The results are obtained when the layer height of the glass beads of μm is 10 mm. For reference, the curve (B) shows the result when the viscoelastic sheet having a thickness of 1 mm is adhered to the back surface of the beam 51 (FIG. 14), and the curve (C) shows the result when the powder 3 is not filled. Shown. Here, FIGS. 16A and 16B show the elastic vibration mode (particle elastic deformation) of the granular material 3 filled in the panel, and FIGS. 17A and 17B show the convection mode (particle-to-particle FIG. 18A shows vibration energy attenuation due to friction.
(B) shows a jump mode (absorption of vibration energy due to particle collision) of the granular material 3.

As can be seen from FIG. 15, the loss coefficient changes according to the magnitude of the vibration acceleration level. The level of vibration generated by general machinery and equipment is 1
It is often 10 dB or less, and in that region, the loss coefficient shows a value of 0.1 or less, and the vibration damping performance is not sufficient. In other words, in the conventional example, it can be said that the effect is obtained when the vibration acceleration level La is relatively large at 110 dB or more.

However, the vibration acceleration level is 110 dB.
In the following cases, elastic vibration is excited in the granular material layer,
Small elastic deformation between the particles occurs. During this deformation, the vibration energy is converted to heat energy and the vibration energy is absorbed. However, in the conventional example, the particles are hard, so the elastic deformation between the particles is small, and as shown in FIG. There was a problem that was small.

[0011]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above points, and an object thereof is to provide excellent vibration acceleration levels La under a wide range of vibration conditions including a vibration of 110 dB or less. An object of the present invention is to provide a vibration damping panel having improved vibration damping performance.

[0012]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides two plate members 2 and 2 opposed to each other at an interval.
It is characterized by being filled with high-rigidity particles 7 whose surface is coated with a low-elasticity material 6 therebetween, and with such a configuration, a low-elasticity coating material exists on the surface of the high-rigidity particles 7. As a result, the low-elastic coating materials come into contact with each other and deform at the contact points between the particles,
Since the elastic deformation of the surface between the particles increases, and the energy is attenuated accordingly, the vibration energy is more efficiently absorbed even when the vibration at the vibration acceleration level of 110 dB or less is received.

Here, it is preferable that the low elastic material 6 coated on the high rigidity particles 7 has a Young's modulus smaller than 10 ⁶ (N / m ² ). The hysteresis attenuation increases, and a loss coefficient of 0.1 or more, which is said to have high damping performance, can be easily obtained.

The low-elasticity material 6 coated on the high-rigidity particles 7 includes acrylonitrile-butadiene rubber (NBR), styrene-butanediene rubber (SBR),
It is preferable to use a rubber material such as butyl rubber (IIR), synthetic rubber typified by chloroprene rubber (CR), or natural rubber (NR). With such a configuration, low elasticity (Young's modulus is 10 ⁶ N / m ² or less), it can be expected a high hysteresis damping.

The material density of the high-rigidity particles 7 is 10
It is preferably adjusted to the range of 00 to 12000 (kg / m ³ ). With such a configuration, the amount of deformation of the high-rigidity particles 7 becomes too large due to inertia of the particles,
It can be prevented from becoming too small.

It is preferable that the particle layer 8 coated with the low elastic material 6 is filled with a gap 9 between the plate material 2 and the plate layer 2. Can be prevented from being directly transmitted to the plate member 2 of the vibration damping panel 1 by the gap 9, and the vibration damping effect is improved.

Preferably, the gap height H between the particle layer 8 coated with the low elastic material 6 and the plate material 2 is at least 2% of the particle layer height D. Thus, the gap 9 can effectively prevent the vibration of the coating particles subjected to the vibration from directly transmitting to the plate member 2 of the vibration damping panel 1.

Further, it is preferable that the particle layer 8 coated with the low elastic material 6 is divided by the partition 4, so that the energy absorption phenomenon due to the friction between the coating particles and the partition 4 during panel vibration can be prevented. In addition, the damping performance is further improved.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a typical embodiment of a vibration damping panel 1 according to the present invention will be described.

As shown in FIG. 1, the surface of the vibration damping panel 1 of the present embodiment is coated with a low elastic material 6 in a space 5 between two plate members 2 facing each other at an interval. High rigidity particles 7 are filled. In this example, the space 5 between the two plate members 2 is divided by the partition 4, and the divided space 5 is filled with a particle layer 8 made of coating particles coated with a low elastic material. In addition, at the time of panel vibration, an energy absorption phenomenon due to friction between the partition 4 and the coating particles 8a is added, and the vibration damping performance is improved.

The high-rigidity particles 7 are made of, for example, spherical glass beads. Here, in order to improve the performance of the damping panel 1, the material density of the high-rigidity particles 7 is set to 1000 to 1000.
It is adjusted to the range of 12000 (kg / m ³ ). That is, the material density of the highly rigid particles 7 is 1000 (kg / m ³ ).
If it is less than the above, the coating particles 8a are deformed due to the inertia of the high-rigidity particles 7, and the hysteresis damping hardly occurs. Further, the material density of the high-rigidity particles 7 is 12000 (kg).
/ M ³ ), the effect of particle gravity increases,
It is because the amount of deformation of the coated particles 8a due to the inertia of the high rigidity grains 7 is reduced, thus, it is preferable to adjust the material density of the high rigidity grains 7 in the range of 1000~12000 (kg / m ^3).

The high-rigidity particles 7 are coated with a low-elasticity material 6 on the surface. The material of the low elasticity material 6 is acrylonitrile-butadiene rubber (NB
R), synthetic rubber represented by styrene-butadiene rubber (SBR), butyl rubber (IIR), chloroprene rubber (CR), and natural rubber (NR). The material limitation for the low elasticity material 6 is that the coating has a low elasticity (Young's modulus is 10 ⁶ N / m ² or less),
This is a condition where high hysteresis attenuation can be expected.

FIG. 2 is a comparative example of the vibration damping performance of the vibration damping panel 1 filled with the above-described coating particles 8a according to the present invention and the particle damping panel of the prior art having a particle layer made of uncoated particles. And the relationship between the vibration acceleration level and the loss coefficient was shown. Here, the panel size was 300 mm x 300 mm, and the panel thickness was 1.2 mm for the upper plate and 0.6 m for the lower plate. The curve (A) shown in FIG.
(Μm) is naturally filled so that the layer height becomes 10 mm. Curve (B) shows glass beads (average particle size of 3) coated with low elastic material 6 (NBR latex).
(00 μm) is naturally filled so that the layer height becomes 10 mm. The mass fraction of the low elastic material 6 in the particle layer 8 used for the measurement is 3%. From FIG. 2, it can be seen that at the vibration acceleration level of 110 dB or less, which is the target of the present invention, the vibration damping performance is excellent.

Here, a mechanism in which the particle layer 8 coated with the low elastic material 7 exhibits a vibration damping performance superior to that of the conventional granular material layer will be described. Regarding the behavior of particles and the principle of vibration damping, FIG. 3 shows a schematic diagram of a particle contact state according to the present invention and a relationship between force and strain at a contact point, and FIG. 4 shows a case of a conventional example. . Here, the conventional particles receive a vibration at a vibration acceleration level of 110 dB or less, so that the elastic deformation of the surface between the particles is small, and the relationship of the particle deformation to the force is expressed by a straight line as shown in FIG. Is done.

On the other hand, in the particle layer 8 coated with the low-elasticity material of the present invention, the low-elasticity coating materials come into contact with each other and deform at the contact points between the particles, resulting in energy attenuation. The relationship of the deformation is represented by a loop as shown in FIG. This is called a hysteresis loop, and the area in the loop is a factor of the hysteresis attenuation due to the particle deformation. The larger the area in the loop, the larger the vibration energy consumption due to the particle deformation.

That is, in the configuration of the present invention, the high rigidity particles 7
The presence of the low modulus coating on the surface results in greater hysteresis damping at the particle contact points and more efficient absorption of vibrational energy. Moreover, since the powder layer is divided by the partition 4, an energy absorption phenomenon due to friction between the partition 4 dividing the space 5 between the plate materials 2 and 2 and the coating particles 8a is added,
The vibration suppression performance is further improved.

The Young's modulus of the low elastic material 6 coated on the high rigidity particles 7 is, for example, 10 ⁶ (N /
Preferably, it is smaller than m ² ). FIG. 5 shows three kinds of materials having different Young's moduli (acrylonitrile-butadiene rubber (NBR);
5.0 × 10 ⁵ N / m ² , polyurethane; 3.0 × 10 ⁸
9 shows the relationship between the loss acceleration factor and the change in the vibration acceleration level when N / m ² and concrete; 2.7 × 10 ¹⁰ N / m ² ) were coated. Curve (A) in the figure
Shows the results when acrylonitrile-butadiene rubber is used as the low elastic material 6, the curve (B) shows the results when polyurethane is used, and the curve (C) shows the results when concrete is used.

FIG. 5 shows that the use of acrylonitrile-butadiene rubber having a Young's modulus lower than 10 ⁶ N / m ² (curve (A)) is superior to the others. This is because the hysteresis attenuation of the deformation between particles shown in FIG. 3 is large. Accordingly, in order to obtain a loss coefficient of 0.1 or more, which is said to have high damping performance, it is preferable that the low elastic material 6 has a Young's modulus lower than 10 ⁶ N / m ² .

In the vibration damping panel 1 of the present invention, as shown in FIG. 1, the space 5 is filled with the coating particles 8a with a gap 9 between the space 5 and the upper plate 2. Incidentally, when there is no gap between the particle layer 8 and the plate material 2 as shown in FIG. 6, the vibration of the coating particles 8a directly propagates to the upper plate material 2, and the vibration damping effect is reduced. By providing a gap 9 between the particle layer 8 and the plate 2 as shown in FIG. 1, the vibration of the coating particles 8a does not directly propagate to the upper plate 2, thereby improving the vibration damping effect. Is possible.

Here, the height H of the gap between the particle layer 8 and the plate 2 is preferably at least 2% of the height D of the filled particle layer. FIG. 7 shows the relationship between the loss coefficient and the change in the vibration acceleration level when the space 5 is filled with the coating particles 8a. The curve (A) in FIG.
In the case of the packing in which is left, the curve (B) shows the coating particles 8
This is the result when a is filled 100%. Therefore, in order to improve the vibration damping effect, at least the gap height H between the particle layer 8 and the panel is 2% of the height D of the filled particle layer.
It is preferable to provide the above.

Hereinafter, a typical embodiment of the vibration damping panel 1 according to the present invention will be described. (Example) In order to produce the coating particles 8a, a vertical mixer equipped with a stirring blade was used here. The equivalent coating particles 8a can also be produced by using a rotary mixer, a V-type mixer, an airflow stirrer, or the like.

In the following, NBR latex is used as the low elasticity material 6 and glass beads (average particle size is 1) are used as the high rigidity particles 7.
25 μm) was used.

The plate shown in FIG. 8 has a 1/4 inch aluminum honeycomb 100 having a height of 20 mm between an aluminum plate 2 having a thickness of 1.2 mm and an aluminum plate 2 having a thickness of 0.6 mm. The honeycomb 100 has a honeycomb sandwich structure in which the coating particles 8a are filled into the honeycomb 100 at a height of 5 mm by natural filling by free fall and adhered. The size of this plate is 3
It is 00 mm x 300 mm.

Here, the two opposing plate members 2 are not particularly limited, such as metal and wood material. The material of the honeycomb 100 for forming a large number of subdivided spaces / cells is not particularly limited, and for example, an aluminum honeycomb, a paper honeycomb, and other various materials can be used.

The evaluation of the vibration control performance of the above-described honeycomb sandwich panel is performed by the system shown in FIG. this is,
To the vibrator 101 via the impedance head 102,
It is fixed to the center of the honeycomb sandwich 1 and randomly vibrated vertically. At this time, the transfer function inertance (acceleration /
Force) to evaluate the damping performance. Further, a control force is applied so that the excitation force of the random excitation becomes constant with respect to a change in panel conditions.

FIG. 10 shows the measurement results of the transfer function. Curve (A) is a comparative example in which a honeycomb sandwich panel was filled with conventional granules (glass beads having an average particle size of 125 μm), and curve (B) was a case in which the above-described coating particles 8a of the present invention were filled. It is an example. This figure 1
From 0, it is clear that the transfer function according to the present invention has a damping effect in which the peak and dip of the curve due to resonance and anti-resonance are smoothed.

For reference, FIGS. 11 and 12 show the narrow band and 1/3 octave band of the noise level at a position 300 mm away from the center of the panel under the same conditions. The curve A in the figure is a comparative example, and the curve B is the present example. In this example, the reduction of the sound radiated from the panel is clearly seen with the improvement of the vibration damping performance.

[0038]

As described above, according to the first aspect of the present invention, a high-rigidity particle whose surface is coated with a low-elastic material is filled between two opposing plate members at an interval. Therefore, the presence of the low-elastic coating material on the surface of the high-rigidity particles causes the low-elasticity coating materials to come into contact with each other and deform at the contact points between the particles, resulting in a large elastic deformation of the surface between the particles. Due to the energy attenuation, the vibration energy is absorbed more efficiently even when the vibration is received at the vibration acceleration level of 110 dB or less. Accordingly, under a wide range of vibration conditions including a vibration of 110 dB or less, a loss coefficient of 0.1 or more, which is said to have high vibration suppression performance, can be obtained. This makes it possible to enhance the vibration damping effect at a wide range of acceleration levels that cannot be obtained with the panel.

According to the second aspect of the present invention, in addition to the effect of the first aspect, since the Young's modulus of the low elastic material coated on the highly rigid particles is smaller than 10 ⁶ (N / m ² ), The hysteresis damping of the inter-deformation is increased, and a loss coefficient of 0.1 or more, which is said to have high damping performance, can be easily obtained, and the performance of the damping panel can be improved.

According to a third aspect of the present invention, in addition to the effects of the first or second aspect, the low-elasticity material coated on the high-rigidity particles is made of acrylonitrile-butadiene rubber (NBR), styrene-butadiene. Rubber (SB
R), butyl rubber (IIR), chloroprene rubber (C
Since it is made of a rubber material such as a synthetic rubber represented by R) or a natural rubber (NR), a low elasticity (Young's modulus is 10 ⁶ N / m ² or less) and high optimal hysteresis attenuation can be expected by coating.

According to a fourth aspect of the present invention, in addition to the effects of the first to ^third aspects, the material density of the high-rigidity particles is in the range of 1000 to 12000 (kg / m ³ ). Since the adjustment is performed, it is possible to prevent the deformation amount of the particles from being too large or too small due to the inertia of the high-rigidity particles, and to improve the performance of the vibration damping panel.

According to a fifth aspect of the present invention, in addition to the effect of any one of the first to fourth aspects, a particle layer coated with a low elastic material is filled with a gap between the plate layer and the plate material. Therefore, the vibration of the coating particles subjected to the vibration can be prevented from directly transmitting to the plate material of the vibration damping panel by the gap, and the vibration damping effect is improved.

According to a sixth aspect of the present invention, in addition to the effect of any one of the first to fifth aspects, the height of the gap between the particle layer coated with the low elastic material and the plate material is: Since the height is 2% or more of the height of the particle layer, the vibration can effectively prevent the vibration of the coated particles from directly propagating to the plate member of the vibration damping panel, thereby improving the vibration damping effect.

According to the seventh aspect of the present invention, in addition to the effect of any one of the first to sixth aspects, the particle layer coated with the low elasticity material is divided by the partition, so that the coating layer is separated from the coating particles when the panel is vibrated. The energy absorption phenomenon due to the friction with the material is added, and the vibration damping performance is further improved.

[Brief description of the drawings]

1A and 1B show an example of an embodiment of the present invention, wherein FIG. 1A is a perspective view of a vibration damping panel, FIG. 1B is a cross-sectional view taken along line XX of FIG.
(C) is an enlarged view of a part (b) of (b).

FIG. 2 is a graph showing a relationship between a loss coefficient and a vibration acceleration level, wherein a curve (A) shows a conventional panel and a curve (B) shows a vibration damping panel of the present invention.

3A is a conceptual diagram of a coating particle, FIG. 3B is an enlarged view of a portion C in FIG. 3A, and FIG. 3C is a graph showing a hysteresis characteristic thereof.

4A is a conceptual diagram of a particle layer whose surface is not coated with a low elasticity material, FIG. 4B is an enlarged view of a portion B in FIG. 4A, and FIG. 4C is a graph showing a hysteresis characteristic thereof. .

FIG. 5 is a graph showing a relationship between a vibration acceleration level and a loss coefficient in coated particles having low elastic materials having different Young's moduli.

6A is a perspective view of the vibration damping panel when the coating particles are 100% filled, FIG. 6B is a cross-sectional view taken along line YY of FIG. 6A, and FIG. FIG.

FIG. 7 is a graph showing a decrease in a loss coefficient with respect to a vibration acceleration level by filling 100% of the coating particles in the same space.

FIG. 8 is a conceptual diagram illustrating an example of a method for producing a vibration damping panel according to the embodiment.

FIGS. 9 (a) and 9 (b) are conceptual diagrams of a system for measuring the damping performance of the damping panel of the above.

FIG. 10 is a graph showing the vibration damping performance in the example of the present invention.

FIG. 11 is a graph showing a noise level (narrow band) according to the embodiment of the present invention.

FIG. 12 shows the noise level (1 / 3Ban) of the embodiment of the present invention.
It is a graph which shows d).

13A is a perspective view of a vibration damping panel filled with a granular material according to a conventional example, and FIG. 13B is a cross-sectional view taken along line ZZ of FIG.

FIG. 14 is a conceptual diagram of a beam damping performance evaluation system using beams.

FIG. 15 is a graph of a loss coefficient with respect to a vibration acceleration level.

FIGS. 16 (a) and (b) are schematic diagrams of behavior of an elastic vibration mode (particle elastic deformation) of a granular material.

17 (a) and (b) are schematic diagrams of the behavior of a granular material in a convection mode (damping of vibration energy due to friction between particles).

FIGS. 18 (a) and (b) are schematic diagrams of a behavior of a granular material in a jump mode (absorption of vibration energy due to particle collision).

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 damping panel 2 plate material 4 partition 5 space 6 low elastic material 7 high rigid particles 8 coated particle layer 9 gap D particle layer height H gap height

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yuzo Okuhira 1048 Kazuma Kadoma, Kadoma City, Osaka Prefecture F-term in Matsushita Electric Works Co., Ltd. AK29B AK29J AK73B AL01B AN01B AN02B AP00A AP00C BA03 BA06 BA10A BA10C DC02B DE01B DE04B DE10B GB90 JA13B JK01B JK07B JK11 YY00B

Claims (7)

[Claims] 1. A vibration-damping panel characterized in that a high-rigidity particle whose surface is coated with a low-elasticity material is filled between two opposing plate members at an interval. 2. The vibration-damping panel according to claim 1, wherein the Young's modulus of the low-elasticity material coated on the high-rigidity particles is smaller than 10 ⁶ (N / m ² ). 3. The low-elasticity material coated on the high-rigidity particles is acrylonitrile-butadiene rubber (NB)
R), a rubber material such as synthetic rubber represented by styrene-butanediene rubber (SBR), butyl rubber (IIR), chloroprene rubber (CR), or natural rubber (NR). Item 2. The vibration damping panel according to Item 2. 4. The material density of the high-rigidity particles is 1000 to 1
2000 (kg / m ^Three)
The system according to any one of claims 1 to 3, wherein
Swing panel. 5. The vibration damping panel according to claim 1, wherein the particle layer coated with the low elastic material is filled with a gap between the particle layer and the plate material. 6. The height of the gap between the particle layer coated with the low elasticity material and the plate material is at least 2% of the height of the particle layer. The vibration damping panel described in. 7. The vibration damping panel according to claim 1, wherein the particle layer coated with the low elasticity material is divided by a partition.