KR101033395B1 - Acoustic absorber of automobile - Google Patents

Abstract

The present invention is a vehicle sound absorbing material composed of three layers of sound absorbing materials having different apparent densities consisting of low melting point fibers (LMF) and high melting point fibers (SF), wherein the sound absorbing material for automobiles is 30 ~ 30 compared to the area of the low density sound absorbing material, the low density sound absorbing material It is a three-layer structure including a high density sound absorbing material disposed at 100% and a non-breathable layer made of rubber or resin material disposed at 10 to 90% of the area of the low density sound absorbing material, and one surface of the low density sound absorbing material is in contact with the noise generating area. The present invention relates to a sound absorbing material for automobiles, wherein the relatively high density sound absorbing material is concentrated in a region having a high noise improvement contribution, and at the same time, a non-breathable material made of rubber or the like between the surface of the high density sound absorbing material or between the low density sound absorbing material and the high density sound absorbing material. By further disposing the layer, it is possible to obtain an effect of improving sound absorbing and insulating performance in the low frequency region.

Description

Acoustic absorber of automobile             

1 is a cross-sectional view of an example of a sound absorbing material for automobiles according to the present invention.

2 is a cross-sectional view of an example of a sound absorbing material for automobiles according to the present invention.

3 is a plan view of an example of a sound absorbing material for automobiles according to the present invention.

DESCRIPTION OF THE REFERENCE NUMERALS

1: low density sound absorber 2: high density sound absorber

3: non-breathable layer 4. dash panel

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to sound absorbing materials for automobiles, and more specifically, after mixing low melting point fiber binders (hereinafter referred to as LMF) and high melting point fibers (hereinafter referred to as SF) such as polyester or polyolefin in a predetermined fineness ratio and weight ratio Manufactured through needle punching and general plush process to have different densities, double or high density layer is used to laminate the heat to the main noise generating area, while laminating with high density sound absorbing material surface or low density sound absorbing material. The present invention relates to a sound absorbing material for automobiles in which a non-breathable layer such as rubber is further disposed between high density sound absorbing materials to improve sound absorbing and insulating performance in a low frequency region.

In general, typical noises introduced into the interior of a vehicle include engine permeation noise generated by an engine and transmitted through a vehicle body or air, and friction noise between wheels and the ground. The engine cover or hood insulator is used to suppress such noise, but the effect of removing the noise is insignificant, and the dash outer attached to the outside of the vehicle and the dash inner attached to the interior of the vehicle, Floor carpets, etc., are responsible for removing most of the noise.

Therefore, in these cases, in order to block the noise flowing into the sound absorbing material in most cases, the sound absorbing and insulating material (hereinafter referred to as sound absorbing material) in which polyurethane foam is separately attached to the sound insulating material layer called heavy layer has been used. In this case, however, the sound insulation performance is excellent, but the assembly (weight) of the assembly (heavy) is usually 6 ~ 9kg / heavier, there is a problem that there is little sound absorption performance against the noise generated in the room. In addition, a method of attaching a separate heavy layer sound insulation material to a vehicle interior to a triple structure sound absorbing material in which a low density material is attached to both surfaces of a high density material is disclosed in Japanese Patent Laid-Open No. 10-236238. The sound absorption effect was insufficient.

As another method, a method is used in which a predetermined binder fiber is added after crushing the dead sand to manufacture a product. In this case, due to the difficult management of our company, the sound absorption is severely deteriorated, and workability deteriorates due to dust generation during processing, investment cost burden due to installation of dust collector, etc., and problems such as odor when it is attached to the inside of the vehicle for a long time. . In addition, in recent years, a method of using a non-woven fabric layer which is heat-bonded with a binder fiber, such as polyolefin and polyester, having a relatively low melting point and a synthetic fiber having a high melting point, has a low density instead of a heavy sound insulation material layer, Many methods have been proposed to reduce the weight of parts by constructing two or more layers with different aeration rates. (Japanese Patent Laid-Open No. 8-152890, Japanese Patent Laid-Open No. 11-180224, Japanese Patent Laid-Open No. 6-247202 6-259080, Japanese Patent Application Laid-Open No. 8-108500, Japanese Patent Application Laid-Open No. 10-247085, and Korean Laid-Open Patent Publication No. 2003-0000746, etc.) However, these methods simply reduce the weight of parts by arranging the nonwoven fabric in a plurality of layers. Compared to the method of attaching the layer can be achieved in part, there was a limit to reduce to the same level as the present invention.

In more detail, in general, in the case of a sound absorbing material composed of a sound absorbing material and a fiber material attached with a heavy layer sound insulating material, a mechanism for transferring sound from the engine to the interior of the vehicle is different. In other words, in the case of the sound absorbing material specification with heavy layer sound insulation material, the noise generated from the engine passes through the dash panel of the vehicle body first, and the passed noise is reflected on the crash pad inside the vehicle. It is then delivered to the sound insulation material again. The reflected sound is finally introduced into the vehicle. When frequency analysis is performed on the introduced noise, most of the rough and loud high frequency sound is more than 1000 Hz. However, in the case of the dual-layer sound absorbing material composed only of fiber material, the noise generated by the engine is primarily reflected through the crash panel of the vehicle body and reflected to the crash pad, which is transmitted to the sound absorbing material part. In this case, most of the high-frequency sound of more than 1000Hz is absorbed, so the noise flowing into the vehicle is changed to a soft sound that is easy to hear, and the sound quality is improved.

In addition, when analyzing the sound pressure distribution through which the noise radiated from the engine passes through the dash panel, the noise center is the largest and the sound pressure drops toward the outside. In other words, the noise improvement contribution of the sound absorbing material in the dasher is the largest part of the dash panel adjacent to the engine and the contribution decreases as the distance goes away. In this case, the structure of the sound absorbing material is applied equally to the corresponding part. no need. However, at present, the sound absorbing material having the same structure is attached to the entire site, and thus, satisfactory weight reduction is difficult in this case, and many problems occur in terms of workability. That is, in the case of the sound absorbing material composed of the same area with the high density layer and the low density layer, the surface strength becomes too hard during and after molding, so that it is difficult to form the sound absorbing material in the angular form for application to the bent portion of the vehicle body. Problems such as poor fitability, such as removal of the product during installation, are frequently encountered.

In addition, in the case of the existing sound absorbing material, the interior noise was improved by shielding the transmission noise of the engine and the like by using the material of the same structure in part or the whole of the noise part (Japanese Patent Laid-Open No. 11-115645, etc.). Or later, the surface of the product is hardened, the formability of the angular form is inferior, and the problem is removed when attached to the fixing pin at the end of the body panel.

Apart from this problem, especially in the case of a vehicle equipped with a diesel engine, considerable low-frequency noise is introduced into the room from the engine part. Therefore, the sound absorbing material alone is inadequate in reducing noise, especially in the noise reduction range of 600 Hz or less. There was a problem.

The present invention, while significantly reducing the weight of the conventional products, by placing a non-ventilable layer in the high noise inflow portion to increase the transmission loss, improve low-frequency indoor noise, as well as high-density sound absorbing material in the top or middle layer The technical problem is to reduce the noise by increasing the sound absorption rate of the indoor space by arranging. Therefore, in the present invention, by selectively disposing a high density sound absorbing material in the area where the engine of the dash panel directly receiving the noise generated by the engine, a fan, a belt portion, etc., and at the same time, a low density sound absorbing material is freely disposed in the overall noise area, By effectively removing the noise generated in the room or entering the room, by placing a non-breathable layer of rubber or resin material between the low density sound absorbing material and the high density sound absorbing material, the weight of the existing sound absorbing material is maintained while maintaining the effect of improving indoor noise, which is the original purpose of the sound absorbing material. In addition to reducing the pressure, the workability, such as formability and wearability, have been remarkably improved. In addition, the invention has also invented a sound absorbing material for automobiles that can improve indoor noise by blocking the inflow of the entire frequency range of noise generated in diesel engines. Could.

Therefore, in the present invention, in the automotive sound absorbing material composed of three layers of sound absorbing materials having different apparent densities composed of low melting point fibers (LMF) and high melting point fibers (SF),

The automotive sound absorbing material is a low-density sound absorbing material, a non-breathable layer made of a high density sound absorbing material disposed in the 30 to 100% of the area of the low density sound absorbing material and a rubber or resin material disposed in 10 to 90% of the area of the low density sound absorbing material The layered structure is provided with a sound absorbing material for automobiles, wherein one surface of the low density sound absorbing material is disposed in contact with the noise generating portion.

Hereinafter, the present invention will be described in more detail with reference to the drawings.

In the present invention, unlike the sound-absorbing material such as polyester-based, which has been composed of a conventional single layer, it is possible to provide a sound absorbing material for automobiles by combining two or more sound absorbing materials through a heat treatment or a separate bonding process by forming a multi-structure having a different apparent density. .

The sound absorbing material for automobiles of the present invention is composed of two stages of sound absorbing materials having different apparent densities of low melting point fibers (LMF) and high melting point fibers (SF), as shown in FIG. A sound absorbing material having a weight of / m 2 is used, and in the case of the high density sound absorbing material (2), it is usually composed of a weight of a surface density of 500 g / m 2 to 2000 g / m 2, and the non-breathable layer 3 is composed of a known rubber or resin material. In the case of the surface density (weight) of the low density and high density sound absorbing material, the range is similar, but the apparent density is different because the thickness of each sound absorbing material is different. For example, if the low-density sound absorber uses a thickness of 15mm, 1000g / ㎡, and the high-density sound absorber uses a thickness of 5mm, 600g / ㎡, two kinds of sound absorbers with different apparent density can be provided.

In the present invention, the application area of the high-density sound absorbing material in the molding process is preferably configured to be about 30 to 100%, more preferably 50% or more of the low-density sound absorbing material application area. And the application area of the non-breathable layer is preferably configured to be 10 to 90%, more preferably 20% or more of the area of the low density sound absorbing material.

In addition, in the present invention, as shown in Figure 1, the low-density sound absorbing material (1) is installed in contact with the noise generating areas such as dash, bottom, ceiling, etc., the high-density sound absorbing material (2) and the non-breathable layer (3) is noise It is preferable to arrange the interior parts so that the improvement effect is large.

When it is configured as described above, when the weight of the high-density sound absorbing material is 600g / m 2 as compared with the existing sound absorbing material, about 180 to 600g / m 2 is used, and the weight of the non-breathable layer is 200 to 200g / m 2. By using about 1800g / ㎡, it is possible to obtain a weight reduction effect of about 50% based on the total weight of the sound absorbing material, so that the sound absorbing and insulating performance, which is the original purpose of the sound absorbing material, can be sufficiently exhibited, while also improving the fuel efficiency of the vehicle. .

At this time, when the high-density sound absorbing material is disposed less than 30% of the area of the low-density sound absorbing material, the original sound absorbing and insulating performance, in particular, the sound absorbing performance is remarkably lowered, which is unsuitable. In this case, it is preferable to arrange and adjust the area appropriately in terms of improving moldability and wearability of the angular portion. In addition, when the non-breathable layer is disposed in less than 10% of the area of the low density sound absorbing material, the noise improvement of less than 600Hz was insignificant. In the present invention, the area of the non-breathable layer is larger than the area of the high-density sound-absorbing material (see Example 5). The product productivity of the structure is further improved.

The sound absorbing material for automobiles of the present invention is a needle punching and mixing so that the apparent density is different after mixing a low melting point fiber binder (hereinafter referred to as LMF) and high melting point fibers (hereinafter referred to as SF) such as polyester-based, polyolefin-based at a predetermined fineness ratio and weight ratio After manufacturing through normal plush process, heat or adhesive is used to laminate relatively low density sound absorbing material to main noise generating area, and high density sound absorbing material is placed between non-breathable layer and low density sound absorbing material or non-breathable layer. It is possible to provide a sound absorbing material for automobiles, which is disposed between the high density sound absorbing material and the low density sound absorbing material and has improved sound absorbing and insulating performance in the low frequency region.

In the present invention, it is preferable that the non-breathable layer is arranged between the high-density sound absorbing material and the low-density sound absorbing material as shown in FIG. 1, or the high-density sound absorbing material is arranged between the non-breathable layer and the low density sound absorbing material as shown in FIG. In the case where the non-breathable layer is disposed between the high density sound absorbing material and the low density sound absorbing material, the sound insulating performance is equivalent to that of the structure of FIG.

The difference in the sound absorbing and insulating performance between the structure of the sound absorbing material of the present invention and the existing material configuration as described above will become more apparent from the examples described later. However, the present invention is not limited to the following examples.

Example 1

Melting point 120 ° C., length 51 mm, 30% by weight of sheath-core low melting polyester fiber of 4 denier, and melting point 255 ° C., length 51 mm, 70 weight% of polyester staple fiber of 6 denia After mixing, a high-density sound absorbing material was manufactured to have a 5 mm thickness and a weight (surface density) of 600 g / m 2 through a needle punching process, and a sheath-core type of 120 deg. Melting point 30% by weight of polyester fiber, 50% by weight of polyester staple fiber having a melting point of 255 ° C, length 51 mm, and 3 deniers of shortness, melting point 255 ° C, length of 51 mm, and 20 deg. By mixing, a low density sound absorbing material was produced at a thickness of 15 mm and a weight (surface density) of 1000 g / m 2. As the non-breathable layer, ordinary synthetic rubber having a weight (surface density) of 2000 g / m 2 was used.

The sound absorbing material was manufactured by arranging the non-breathable layer between the high density sound absorbing material and the low density sound absorbing material through the usual bonding and forming process. The area of the high density sound absorbing material is 100% of the low density sound absorbing material, and the area of the non-ventilating layer is 30 of the low density sound absorbing material. % Was obtained.

EXAMPLES 2-4

Except that the application area of the high-density sound absorbing material in Example 1 100%, the non-breathable layer application area was changed as shown in Table 1 was prepared in the same manner as in Example 1.

EXAMPLES 5-8

In Example 1 was prepared in the same manner as in Example 1 except that the application area of the non-breathable layer was changed to 50%, the application area of the high-density sound absorbing material as shown in Table 1.

Comparative Example 1

Except that the application area of the high-density sound absorption material of the sound absorbing material of Example 1 was 100%, the application area of the non-breathable layer was 100% was prepared in the same manner as in Example 1.                     

Comparative Example 2

A separate EVE layer having a weight (surface density) of 4000 g / m 2 and a thickness of 2 mm was attached, and the same procedure as in Example 1 was carried out except that polyurethane foam was used as the sound absorbing material. However, in the indoor noise evaluation, a product formed by foaming urethane foam on the YBT layer was used.

The sound absorbing performance of the specimens of the sound absorbing materials of Examples and Comparative Examples was measured using a reverberation chamber test equipment. The sound absorption rate of the sound absorbing material is measured by the incidence of the incident light reflected on the sound absorbing material. At this time, the sound absorption rate is higher, the better. In addition, the sound insulation performance of the specimens of the Examples and Comparative Examples was measured using the Apamat test equipment, and the higher the value, the better.

The final product of the above Examples and Comparative Examples was analyzed and compared with the conventional specifications through the interior noise of the diesel engine through the AutoSEA noise, vibration analysis simulation program is shown in Table 2.

division Overall characteristic Sound absorbing material Sound insulation Sound absorbing material High density sound absorbing material Non-breathable layer Low density sound absorbing material weight
(Kg / ㎡) thickness
(Mm) thickness
(Mm) Surface density Application area ratio (%) thickness
(Mm) Surface density Application area ratio (%) thickness
(Mm) Surface density Application area ratio (%) Example 1 2.20 21 5 600 100 One 2000 30 15 1000 100 Example 2 2.60 21 5 600 100 One 2000 50 15 1000 100 Example 3 3.00 21 5 600 100 One 2000 70 15 1000 100 Example 4 3.40 21 5 600 100 One 2000 90 15 1000 100 Example 5 2.18 21 5 600 30 One 2000 50 15 1000 100 Example 6 2.30 21 5 600 50 One 2000 50 15 1000 100 Example 7 2.42 21 5 600 70 One 2000 50 15 1000 100 Example 8 2.54 21 5 600 90 One 2000 50 15 1000 100 Comparative Example 1 3.60 21 5 600 100 One 2000 100 15 1000 100 Comparative Example 2 5.70 20 - - - 2 4000 100 18 1700 100

division Gross weight
(Kg / ㎡) Sound absorption
Evaluation results Sound insulation
Evaluation results SEA simulation evaluation result Weight reduction effect
(%)
(Comparative Example 3) Example 1 2.20 ◎ ○ ◎ 61 Example 2 2.60 ◎ ○ ◎ 54 Example 3 3.00 ◎ ○ ◎ 47 Example 4 3.40 ◎ ○ ◎ 40 Example 5 2.18 ◎ ○ ◎ 62 Example 6 2.30 ◎ ○ ◎ 59 Example 7 2.42 ◎ ○ ◎ 58 Example 8 2.54 ◎ ○ ◎ 55 Comparative Example 1 3.60 ○ ○ ○ 37 Comparative Example 2 5.70 standard standard standard -

◎: Excellent, ○: Normal, ×: Poor.

As described above, according to the present invention, the sound absorbing material of the present invention achieves a weight reduction of about 50% compared to the sound absorbing material with each layer disposed in the same area, thereby improving the fuel efficiency of the vehicle and at the same time improving the workability. In particular, while blocking the noise of the diesel engine, the manufacturing cost of the product can be relatively lowered.

Claims (3)

In the sound absorbing material for automobiles composed of three layers of sound absorbing materials having different apparent densities composed of low melting point fibers (LMF) and high melting point fibers (SF), The automotive sound absorbing material is a low-density sound absorbing material, a non-breathable layer made of a high density sound absorbing material disposed in the 30 to 100% of the area of the low density sound absorbing material and a rubber or resin material disposed in 10 to 90% of the area of the low density sound absorbing material A layered structure, the sound absorbing material for automobiles, characterized in that the one surface of the low density sound absorbing material is disposed in contact with the noise generating portion. The sound absorbing material for automobiles according to claim 1, wherein the three-layer structure is a structure in which the high density sound absorbing material is disposed between the non-breathable layer and the low density sound absorbing material, or a non-breathable layer is arranged between the high density sound absorbing material and the low density sound absorbing material. The sound absorbing material for automobiles according to claim 1, wherein the low density sound absorbing material has a surface density of 500 to 2000 g / m 2, and the high density sound absorbing material has a surface density of 500 to 2000 g / m 2.

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