JPH08179779A - Sound insulating material - Google Patents

Abstract

PURPOSE: To provide a sound insulating material which is excellent in low frequency sound insulating performance and is also excellent in high frequency sound insulating performance. CONSTITUTION: A sound insulating material 1 has a structure that a high density pad material 3, a film 4, a low density pad material 5 and the skin 6 having comparatively large mass are layered in order, and the high density pad material 3 is arranged in a condition of contacting with a wall body 2. A noise and vibration are transmitted to the wall body 2. The high density pad material 3 contacting with the wall body 2 restrains vibration of the wall body 2, and restrains vibration (a low frequency noise) transmitted to the wall body 2. A low frequency noise incident on the sound insulating material 1 is attenuated by vibrating the skin 6 supported with the low density pad material 5. On the other hand, a high frequency noise incident on the sound insulating material 1 is absorbed by the high density pad material 3, and the high frequency noise passing through the high density pad material 3 is reflected by the film 4, and is again absorbed by the high density pad material 3. That is, the high frequency noise is reflected between the wall body 2 and the film 4, and is absorbed in the high density pad material 3 with high efficiency.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sound insulating material used in automobiles, electric equipment, building equipment and the like.

[0002]

2. Description of the Related Art A conventional sound insulating material is a pad material such as glass wool, felt, or foam resin provided with a surface skin, and is applied to a wall body so that the pad material faces. That is, the pad material is sandwiched between the wall body and the skin. By adopting this structure, for example, when sound enters from the wall body side, part of the sound is reflected by the wall body, and the sound passing through the wall body is reduced. And the sound that has passed through the wall and entered the pad material, or the sound that has traveled through the wall and entered the pad material is
Sound is absorbed by the pad material while it is reflected between the wall body and the epidermis. Therefore, the sound that passes through the skin, that is, the sound that passes through the sound insulation material is significantly reduced.

Here, the sound wave has a wide band from a low frequency to a high frequency. When the density is low, the pad material insulates vibration of low frequency but does not have excellent sound absorbing performance. On the contrary, when the density is high, it has a property of absorbing sound wave of high frequency, but has poor vibration insulation. That is, in the conventional sound insulation material, the pad material used can insulate sound waves in one of the high frequency region and the low frequency region, but cannot sufficiently insulate sound waves in the other low frequency region or the high frequency region. .

This will be specifically described. When the density of the pad material is set to be high so that the pad material absorbs sound at a high frequency that passes through the wall body, low-frequency vibration that propagates through the wall body and enters the pad material is transmitted to the epidermis as it is. Emitted as sound from the epidermis. On the contrary, if the density of the pad material is set low so as to insulate the low frequency vibration that is transmitted through the wall and incident on the pad material, the pad material is sufficient for the high frequency sound that passes through the wall. Sound cannot be absorbed, and high frequency sound passes through the sound insulation material.

As a means for solving this problem, the epidermis,
A sound insulating material having a three-layer structure composed of a low-density pad material and a high-density pad material is known. This three-layer sound insulation material is a high-density pad material on the wall side and a low-density pad material on the skin side. The high-density pad material absorbs high-frequency sound,
The low density pad material is used to insulate the vibration, and the high density pad material is used to suppress the vibration of the wall body.

[0006]

When the thickness of the three-layer sound insulation material is made equal to the thickness of the two-layer sound insulation material (skin + pad material), the high-density pad material in the three-layer sound insulation material and The thickness of the low-density pad material is halved as compared with the pad material of the sound insulating material having the two-layer structure. And 3
The low frequency sound insulation performance of the layered sound insulation material is relatively improved by the insulation of the low frequency vibration by the low density pad material and the suppression of the wall vibration by the high density pad material, but the high frequency sound insulation performance is high. It did not improve so much because the material was halved.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a sound insulation material having both low frequency sound insulation performance and high frequency sound insulation performance without causing a large increase in cost.

[0008]

The sound insulating material of the present invention employs the following technical means. (Claim 1) The sound insulating material according to the present invention is arranged along a wall body, and a high-density pad material for high-frequency sound insulation and a side of the high-density pad material different from the wall body. Low-frequency soundproof low-density pad material disposed on a surface, a film disposed between the high-density pad material and the low-density pad material, and the film of the low-density pad material on a different side. And a skin having a large mass disposed on the surface.

The high frequency and the low frequency used in the present invention are relative, and a frequency lower than a predetermined frequency is a low frequency and a frequency higher than the predetermined frequency is a high frequency.
Similarly, the high and low densities used in the present invention are also relative, with a density lower than a predetermined density being a low density and a density higher than that being a high density.

(Claim 2) In the sound insulation material according to claim 1,
The high-density pad material has a density that mainly absorbs sound waves that have passed through the wall body, and the low-density pad material has a density that mainly insulates vibrations transmitted from the wall body. .

[0011]

The operation of the sound insulating material of the present invention will be described by taking the case where sound enters from the wall side as an example. For ease of explanation, the sound insulation of low frequency sound and the sound insulation of high frequency sound will be described separately. When low-frequency sound enters from the wall side, part of the sound is reflected by the wall, and low-frequency sound passing through the wall is reduced. Further, since vibration of the wall body is suppressed by the high density pad material, it is possible to suppress low frequency sound transmitted through the wall body from entering the high density pad material and the low density pad material. The low-frequency sound that has entered the high-density pad material from the wall body is slightly absorbed by the high-density pad material, then passes through the film and enters the low-density pad material. The low-frequency sound that has entered the low-density pad material from the film is attenuated by the low-density pad material covered with a large-mass skin. As a result, low-frequency sound passing through the skin, that is, low-frequency sound passing through the sound insulation material is significantly reduced.

When a high frequency sound is incident from the wall side, a part of the sound is reflected by the wall body and the high frequency sound passing through the wall body is reduced. The high-frequency sound that has entered the high-density pad material from the wall body passes through the high-density pad material, and then is reflected by the film toward the high-density pad material again. That is, high-frequency sound is absorbed by the high-density pad material while being reflected between the film and the wall. As a result, the high frequency sound passing through the membrane is significantly reduced. The high-frequency sound that has entered the low-density pad material from the film is slightly absorbed by the low-density pad material and reaches the epidermis. Part of the high frequency waves that have reached the epidermis is reflected back to the low density pad material side, and the remaining part of the high frequency sound passes through the epidermis. In this way, the high-frequency sound that has passed through the wall is first absorbed by the high-density pad material, is then reflected by the film, and is again absorbed by the high-density pad material. Decrease.

[0013]

As described above, the sound insulation material of the present invention has a low-frequency sound insulation effect due to the low-frequency insulation effect of the low-density pad material and the skin and the wall suppression effect of the high-density pad material. In addition to excellent performance, it also excels in high-frequency sound insulation due to the high-frequency sound absorption effect of the high-density pad material and the high-frequency reflection effect of the film. Further, since the present invention can be carried out only by adding a film to the conventional sound insulating material having a three-layer structure,
It is possible to provide a sound insulation material having high sound insulation performance while suppressing an increase in cost.

[0014]

EXAMPLES Next, a sound insulation material of the present invention will be described based on an example shown in the drawings. [Structure of Embodiment] FIG. 1 is a cross-sectional view of a main part of a sound insulating material mounted on a wall. The sound insulating material 1 is arranged on the vehicle wall body 2 such as a partition wall between the engine room and the room and a partition wall between the room and the outside, and blocks noise that enters the room through the wall body 2. The sound insulating material 1 has a structure in which a high-density pad material 3, a film 4, a low-density pad material 5, and a skin 6 are sequentially laminated, and the surface of the high-density pad material 3 different from the film 4 is a wall body. It is arranged in a state of being in contact with the surface of 2. The thickness of the sound insulating material 1 is set based on constraints such as sound insulating characteristics, habitability in the vehicle interior, and avoiding interference with other devices. The thickness of the sound insulating material 1 when mounted on a vehicle as in this embodiment is: Generally about 10.0-40.
It is provided in the range of 0 mm.

The high density pad material 3 has a relatively high density (about 0.02 to 0.02) so as to mainly absorb a sound of a relatively high frequency (200 Hz or more) that has passed through the iron plate which is the wall 2.
The pad material is in the range of 8 g / cm ³ ) and uses, for example, felt (cotton felt or the like) and foam resin (urethane foam or the like).

The low-density pad material 5 has a relatively low density (about 0.005 to 0.50%) so as to mainly insulate vibration of a relatively low frequency (200 Hz or less) transmitted through the iron plate which is the wall body 2.
The pad material is in the range of 04 g / cm ³ ) and uses, for example, low density glass wool or low density felt (such as chemical fiber felt).

The film 4 is a film having a relatively high density capable of reflecting a sound having a relatively high frequency (200 Hz or more), and is made of, for example, a resin film, a high density paper, a high density cloth, or a metal thin film.

The skin 6 is made of a resin material such as vinyl chloride resin or a rubber sheet having a relatively large mass (about 1.0).
~ 10.0 kg / m ² range, preferably about 3.0 ~
(Range of 5.0 kg / m ² ), having a shape for covering the high-density pad material 3 and the low-density pad material 5 with the membrane 4 sandwiched therebetween, and having strength to withstand assembly work and vehicle vibration.

(Operation of Example) The sound insulation performance of the sound insulation material 1 will be described based on experimental data. 2 is a graph showing the experimental results. This graph shows experimental data (broken line, one-dot chain line, two-dot chain line) of three types of conventional products and experimental data (solid line) of Example products to which the present invention is applied.

Here, the broken line is data of a sound insulating material having a two-layer structure consisting of the high-density pad material 3 and the skin 6, and the details are the high-density pad material 3 with a thickness of 30 mm and the skin 6 with a mass of 3.7 kg / m ² . Consists of. The alternate long and short dash line is the data of the two-layered sound insulating material including the low-density pad material 5 and the skin 6, and the details are composed of the low-density pad material 5 having a thickness of 30 mm and the skin 6 having a mass of 3.7 kg / m ² . The two-dot chain line is the data of the conventional three-layer sound insulation material consisting of the high-density pad material 3, the low-density pad material 5, and the skin 6, and the details are the high-density pad material 3 with a thickness of 15 mm on the wall 2 side + the thickness. It consists of a 15 mm low-density pad material 5 and a skin 6 having a mass of 3.7 kg / m ² .

The solid line is the data of the sound insulating material 1 having the four-layer structure (high-density pad material 3 + membrane 4 + low-density pad material 5 + skin 6) adopting the present invention. Pad material 3 + resin film 4 + thickness 15 mm
Of low-density pad material 5 + mass of 3.7 kg / m ² of skin 6. In the experiment, an iron plate having a thickness of 1.6 mm was used for the wall body 2 and the sound insulation characteristic of the sound radiated from the iron plate side was obtained. Further, the plurality of peak values shown in the graph are due to the resonance of the iron plate used in the experiment.

The sound insulation material using only the high-density pad material 3 is
As indicated by the broken line, the sound insulation performance at low frequencies below 200 Hz is low. Sound insulation using only low-density pad material 5
As indicated by the alternate long and short dash line, the sound insulation performance at low frequencies of 200 Hz or lower is high, but the sound insulation performance at high frequencies of 200 Hz or higher is slightly deteriorated as compared with the broken line (sound insulation material using only the high-density pad material 3). As shown by the chain double-dashed line, the conventional sound insulation material having a two-layer structure has a high sound insulation performance at a low frequency of 200 Hz or lower, but the sound insulation performance at a high frequency of 200 Hz or higher is not improved so much.

The sound insulating material 1 having a four-layer structure adopting the present invention is
As indicated by the solid line, the sound insulation performance at low frequencies below 200 Hz is high. In addition, the sound insulation performance for high frequencies of 200 Hz or higher has been dramatically improved. This high frequency sound insulation performance is
This is far superior to the broken line (sound insulation using only the high-density pad material 3). The low-frequency sound insulation performance is improved by the low-frequency vibration insulation effect of the low-density pad material 5 and the skin 6, and the suppression effect of the wall 2 by the high-density pad material 3. In addition, the improvement of high-frequency sound insulation performance is
The high-frequency sound absorption effect of the high-density pad material 3 and the high-frequency sound reaching the film 4 from the high-density pad material 3 are reflected by the film 4 back to the high-density pad material 3 (Refer to the arrow in FIG. 1). See) and.

(Effects of Examples) The sound insulation material 1 adopting the present invention is excellent not only in low frequency sound insulation performance but also in high frequency sound insulation performance, as can be seen from the above experimental data. That is, both the low-frequency noise due to the vibration transmitted through the wall body 2 and the high-frequency noise that has passed through the wall body 2 can be effectively insulated by the sound insulation material 1 of the present invention.

Further, as can be seen from the graph, the peak value due to the resonance of the wall body 2 is remarkably suppressed, especially after the second order, and the inclination before and after the peak is moderately suppressed. That is, the frequency characteristic of noise is flattened. In this way, the resonance sound peculiar to the vehicle is suppressed to a low level, and the frequency of the noise is made uniform, so that the effect that the noise is less likely to reach the ears of the occupant is exhibited. Furthermore, since the present invention can be carried out only by adding the film 4 to the conventional sound insulating material 1 having a three-layer structure, it is possible to suppress the cost increase and manufacture the sound insulating material 1 having high sound insulating performance.

(Modification) In the above embodiment, the example in which the sound insulating material is used in the vehicle is shown, but it may be applied as a sound insulating material used in audio equipment, OA equipment, home appliances, building equipment and the like. Further, the high density pad material may be provided in two or more layers, and a film may be provided between the layers of each high density pad material. That is, in the above embodiment, the example of the two layers of the high density pad material and the low density pad material is shown. However, the sound insulation of a three-layer structure or more in which a plurality of high density pad materials are provided and a film is arranged between each layer Good as a material. The density of the high-density pad material of each layer may be the same or different.

[Brief description of drawings]

FIG. 1 is a sectional view of a main part of a sound insulation material.

FIG. 2 is a graph showing experimental results.

[Explanation of symbols]

 1 Sound Insulation 2 Wall 3 High Density Pad Material 4 Membrane 5 Low Density Pad Material 6 Skin

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display area E04B 1/86 NG10K 11/16 // B29K 105: 04

Claims (2)

[Claims] 1. A sound insulation material arranged along a wall body, comprising a high-density pad material for high-frequency sound insulation, and a low-density material arranged on a surface of the high-density pad material on a side different from the wall body. Low-density pad material for frequency soundproofing, a film arranged between the high-density pad material and the low-density pad material, and a mass arranged on the surface of the low-density pad material different from the film. Sound insulation with a large skin. 2. The sound insulating material according to claim 1, wherein the high-density pad material has a density that mainly absorbs sound waves that have passed through the wall body, and the low-density pad material vibrates from the wall body. A sound insulation material having a density that mainly insulates.