EP4351930A1

EP4351930A1 - An insulator with high acoustic efficiency

Info

Publication number: EP4351930A1
Application number: EP21945319.8A
Authority: EP
Inventors: Zahide OZTAS KAPLAN; Serdar EKEN; Hasan AGAOGLU
Original assignee: A Plas Genel Otomotiv Mamulleri Sanayi Ve Ticaret AS
Current assignee: A Plas Genel Otomotiv Mamulleri Sanayi Ve Ticaret AS
Priority date: 2021-06-11
Filing date: 2021-08-23
Publication date: 2024-04-17
Also published as: TR202109601A2

Abstract

The invention relates to an insulator (10) with high acoustic efficiency that has different geometric shapes according to the low or high frequency sound exposure situation in certain regions in accordance with the sound map extracted on it, which is in a form that can be used in the instrument panel section of the vehicle (15), floor carpets (16) and ceiling coverings (14).

Description

AN INSULATOR WITH HIGH ACOUSTIC EFFICIENCY

Technical Field

The invention relates to an insulator designed as an acoustic solution for problems such as engine noise, road noise, or wind noise in motor vehicles.

The invention in particular relates to an insulator with high acoustic efficiency that has different geometric shapes according to the low or high frequency sound exposure situation in certain regions in accordance with the sound map extracted on it, which is in a form that can be used in the instrument panel section of the vehicle (firewall panel), floor and ceiling coverings.

Prior Art

It is known that insulation materials are used in the floor carpets, ceiling coverings, instrument panel sections of vehicles in order to ensure that the drivers and passengers are least affected by external sounds in motor vehicles, especially in land vehicles. Although standard insulation materials are used in ceiling and floor applications, different applications have been developed to provide sound insulation, especially between the engine compartment and the driver compartment. Drivers and passengers in the vehicle are exposed to noise from the motor vehicle's engine from the front side and therefore acoustic processing is required to achieve the desired noise comfort in the passenger compartment. For this purpose, it is known that such a compartment is achieved by providing a sound insulation material on the passenger compartment side between the motor and passenger compartments. These sound insulation materials are materials that require a significant thickness of material to achieve the desired noise comfort in modern motor vehicles. It is also known that noise insulation material is applied to the engine compartment side of the wall in the form of an insulation piece. These known structures have disadvantages in two respects. On the one hand, the coating of the front wall's passenger compartment side can only be installed under complex conditions, so there are increasing production costs. It should also be noted that coating difficulties rises in proportion to the increase in coating thickness. On the other hand, due to the considerable coating thickness needed for today's noise comfort, such known structures lead to a decrease in the size of the passenger compartment, which contradicts the current requirements, that is, thinner coatings are needed to create a passenger compartment with as large a volume as possible. To eliminate this problem, American patent no. US4655496, owned by Stankiewicz Alois Dr Gmbh, offers a different solution. The purpose of the said patent is to produce a partition between the engine and passenger compartments which, when the amount of noise-insulating material is reduced, makes possible at least a reduction in the amount of covering needed on the passenger compartment side. Therefore, a simplified application of the covering on the engine compartment side is provided. Also, the said invention describes a partition for separating the engine and passenger components of a motor vehicle, comprising a wall between the compartments and a covering of noise-insulating material on the engine compartment side of the wall, the partition including at least one convex or concave deformation.

It is also known that various companies have various studies and patents showing the advantages of the materials with sound insulation placed between the engine compartment and the passenger compartment and the characteristics of the materials they are produced. For example, in patent no. KR20060003276, which is a joint invention of the firm NVH KOREA INC., a sound-absorbing material for automobile interiors is developed. Accordingly, the purpose of the said invention is to improve the moldability and workability of the sound absorption, improves the working environment, and reduce the sensory discomfort caused by the smell and harmful components generated in the sound-absorbing material. In order to achieve the said purpose, the sound-absorbing material for automobile interior is made of at least any one of natural fibers, recycled fibers, polyolefin-based virgin fibers, inorganic fibers, and the like mixed with the felt; and at least one of melamine, epoxy, unsaturated polyester, epoxy polyester, phenol, and epoxy-polyester.

In particular, together with the development of material technology, the developments by embodying different combinations with different components to provide audio isolation and the applications for placing these materials between the engine compartment and the passenger compartment have been made. The patent KR20130006953, also a joint invention of NVH Korea Inc., describes a method of producing a highly efficient, multilayered sound absorbent material for a vehicle, a sound-absorbent main layer, and a surface protection layer. In the said invention, the sound-absorbing material main layer formed by laminating two or more selected resin resins, inorganic fibers, and foamed foams has a multilayer structure, and a surface protective layer laminated on one or both surfaces of the sound-absorbing material main layer. It is described here that a multi-layer sound-absorbing material is consists of the inorganic fiber having a high-performance multilayer sound absorbing material for automobiles, made of one or more selected from glass wool, glass fiber, basalt fiber, and carbon fiber. Here, inorganic fibers are composed of a mixing ratio containing 5 to 50% by weight thermosetting resin for each fiber bond.

In patent no. KR20130058912, also a joint invention of NVH Korea Inc., a polyurethane composition, which is provided to be compress molded, to improve an absorbing performance and a heat resistant performance, and to satisfy physical properties as vehicle interior materials, is formed by mixing thermoplastic resin powder, calcium carbonate powder and/or expanded graphite powder, graft pulp powder and/or aluminum short fiber, into foam polyurethane raw materials, is described. It is said that the thermoplastic resin powder is selected from polypropylene resin, polyethylene resin, polyvinylchloride, nylon, polycarbonate, polyethylene terephthalate, polymethyl methacrylate, polyoxymethylene, polystyrene, ABS resin, Teflon resin, phenol resin, melamine resin, and a mixture thereof. The present invention constitutes a priority technical literature on the implementation of polyurethane materials on the partition walls used between the engine compartment and the passenger compartment.

Along with the above-described patents, there are many patents for the compositions of the material to be used between the engine compartment and the passenger compartment for sound insulation; in patent no. US2014306142, a joint invention of Hyundai Motor Co, a different polyamide resin composition was used, and barium sulfate was preferred for sound insulation. In the said patent, a polyamide resin composition for sound insulation, which includes a polyamide 66 or polyamide 6 resin, a glass fiber for improving mechanical and heat resistance properties of the composition is explained. The fact that the thickness is very thin in the area where the sound insulation materials placed between the engine compartment and the passenger compartment are used and the material weights are limited in accordance with production standards has made the production of both thinner and lighter insulation material inevitable. In this sense, in the patent no. JP2015209206, a first sound absorbent layer made of micro fiber, a sound blocker layer made of thermo plastic resin, and a second sound absorbent layer made of thermoplastic fibers or thermoplastic modified cross-section fibers are described.

Insulators produced by traditional methods are products with limited efficiency due to their natural structure. Accordingly, in addition to conventional isolators, the production of insulators in new types of material and designs has been carried out. In traditional methods, when it is necessary to increase sound insulation, methods such as increasing the thickness or weight of the insulation material are usually used. But improvements made in this way are not suitable for lightweight design engineering. Today, the use of lightweight designs in the automotive industry has become a necessity in many ways. In this sense, the insulators used must also be designed in accordance with the lightweight design idea. Therefore, lightweight designs are intended to increase acoustic efficiency by reducing the weight of insulators. When newly developed applications are examined, it is known that metamaterials with acoustic efficiency increased by resonance are effective. Metamaterial applications are being developed to replace traditional insulation materials. Acoustic research studies have been conducted on the use of metamaterials in the automotive industry, in the floor carpet section of vehicles, ceiling coverings, and on the instrument panel. Important computational processes are carried out in the development of these parts in the vehicle. In these studies, it has been observed that it reduces vibrations and provides better sound insulation.

When all the available technical literature and patent applications described as above are examined, it is seen that studies are carried out on the chemical properties and composition rates of the materials placed for sound insulation between the engine compartment and the passenger compartment. However, there is no development of an effective sound insulation to be obtained by changing the physical properties of the material in any application in the current technique. In fact, the maximum level of sound insulation to be obtained by the change in the physical structure of the material constitutes the main purpose of all existing applications. With this invention, the inventor aims to provide adequate sound insulation with geometric forms (square pyramid, triangular pyramid, etc.) to be formed on the outer surfaces of sound insulation materials -especially placed between the vehicle engine compartment and the passenger compartment- as a result of his R&D efforts to present a very different innovation to the technical literature. While the inventor aims to apply the acoustic sound insulation model to be applied between the engine compartment and the passenger compartment, it aims to develop an isolation material that can be used in different dimensions and thicknesses that can be used anywhere in vehicles. In fact, as a result of the studies carried out according to the thickness and weight of the insulation materials used between the engine compartment and the passenger compartment, it was understood that the said acoustic system could be provided with geometric forms to be created on the relevant materials.

When all the technical literature and patent applications presented above, together with the patent applications and some applications of the previous technique that we used only as an example, are examined, no insulator is found that satisfies the following: which does not cause an increase in the total weight of the relevant parts when used to separate motor and passenger components of motor vehicles and used as a regional patch on the firewall panel, which is a wall between the compartments, and also which provides serious sound insulation when used in an audio map as an insulating material patch.

Although the said insulation material is in a form that will isolate the engine sound by being placed in the vehicle between the engine compartment and the passenger compartment, it aims to isolate the inside of the vehicle by isolating external factors such as wind noise and road noise that the occupants of the vehicle are exposed to.

The Objects of the Invention

The object of the invention is to ensure that the interior of the vehicle is isolated from these sounds by effectively isolating external factors such as engine sound, wind sound and road sound that are exposed to those inside the vehicle. In this sense, the application of the invention may be applied to any desired area in the vehicle, such as the vehicle floor coverings, engine bottom and upper housing, fender interior coatings. The object of the invention is to introduce an application that will eliminate engine noise problems by increasing insulation performance.

More specifically, the object of the invention is to provide an insulator which does not cause an increase in the total weight of the relevant parts when used to separate motor and passenger components of motor vehicles and used as a regional patch on the firewall panel, which is a wall between the compartments, and also which provides serious sound insulation when used in an audio map as an insulating material patch.

In order to eliminate the disadvantages of known applications of the technique, the object of the invention is to introduce new types of materials and designs apart from traditional insulators.

The object of the invention is to predict a metamaterial that reduces vibrations and provides better sound insulation. Due to the fact that metamaterial has polypropylene (PP) and barium sulfate (BaS04) structure with a high specific gravity in alternative applications, a high level of heat resistance, noise, and the vibration insulation performance is achieved. Barium sulfate (BaS04) is an inorganic filler that improves the formability and dimensional stability of the existing composition and further increases the specific gravity of the composition, thereby improving its sound insulation property. Since the sound insulation property usually increases in proportion to an increase in the specific gravity of the material, it is preferable to use a high specific gravity barium sulfate to improve the sound insulation property. The insulator of the invention can also be produced from various materials with properties that will provide these advantages.

More specifically, the object of the invention is to maximize noise/sound insulation with geometric forms created on the surface of the sound insulation material, in addition to the improvements made in the existing technique. With acoustic modeling performed to keep the sound in the engine compartment and prevent it from passing into the passenger compartment, geometric forms were created on the sound insulation materials and at the same time, this modeling was ensured that the forms did not exceed the desired weight and thickness.

In order to fulfill the objects described above, the invention is an insulator of polymer material, which provides an effective audio ingestion efficiency in parts such as ground rugs, ceiling coverings and indicator panel, with thermoplastic production techniques, wherein; it is comprising damping protrusions with geometric forms that will create a mass effect to provide efficient sound insulation at sound frequency values of different heights.

In order to accomplish all the advantages mentioned above and to be understood from the following detailed description, the present invention provides many advantages with respect to said features.

The structural and characteristic features and all advantages of the invention outlined in the drawings below and in the detailed description made by referring to these figures will be understood clearly; therefore, the evaluation should be made by taking these figures and detailed explanations into consideration.

Brief Description of Figures

Figure 1 Shows the view of the insulator with a square pyramid form of the invention.

Figure 2 Shows the view of the insulator of the invention as an embodiment of which has a pyramidal and triangular form of geometry and has an integrated (dual) structure that allows for damping various sound frequencies.

Figure 3 Shows the view of the insulator of the invention with a wavy form geometry.

Figure 4 Shows the view of the insulator of the invention with a right angle triangle form geometry.

Figure 5 Shows the view of the insulator with a triangular pyramid form of the invention.

Figure 6 Shows the view of the insulator of the invention with a triangle form geometry.

Figure 7 Shows a graph of the sound absorption coefficient measurements made in the reverberation cabinet.

Figure 8 Shows a graph of the sound transmission loss value measurements made in the reverberation cabinet.

Figure 9 Is an exemplary illustration showing the use of the insulator of the invention for sound insulation in different parts of vehicles. Reference Numbers

10. Insulator

11. Damping protrusions

12. Base Surface

14. Ceiling coating

15. Instrument Panel

16. Floor carpet

SYK. Sound absorption coefficient (a)

OMF. Octave Central Frequency (Flz)

STK. Loss of audio transmission (dB)

Detailed Description of the Invention

In this detailed description, an insulator (10) developed to prevent noise from the engine, wind, and road sound in motor vehicles from entering the interior compartment of the vehicle, and its application and production method are explained only for a better understanding of the subject and without any limiting effect. Along with developments in the automotive industry, the inventor who aims to develop a different insulation material (insulator (10)) to provide acoustic comfort in the vehicle has examined each of the methods and products belonging to the prior art and revealed a novel insulator (10).

The inventor has developed an insulator (10) with high acoustic efficiency in the form that can be used in the instrument panel (15) section of the vehicle, floor carpet (16) and ceiling coatings (14). The said insulator (10) can also be used in all areas requiring sound insulation in the vehicle, such as car base coatings, engine lower and upper housing, fender inner coatings. During the development of the said insulator (10), different materials were used and the most effective results were aimed at testing with these materials. In an embodiment, the insulator (10) of the invention is made of polypropylene (PP) material with barium sulfate addition. In this sense, since the said insulator (10) has a polypropylene (PP) and barium sulfate (BaS04) structure with high specific gravity, it is aimed to obtain a high level of heat resistance, noise, and vibration insulation performance. In addition, the insulator of the invention (10) provides high acoustic efficiency at different frequencies due to its structure with various geometric forms (square pyramid). The insulator (10) of the invention contains damping protrusions (11) with mass effect in order to provide efficient sound insulation at different sound frequency values and can be produced in various geometric forms in accordance with the usage area. Figure 1 shows the view of the insulator (10) with a square pyramid form of the invention. The insulator (10) can be produced in the form of a square pyramid, triangular pyramid, also the lengths of the pyramids - damping protrusions (11) - can be changed according to the frequency intensity in the area where it will be used. The length of the pyramids used in the insulator (10) depends on the frequency values of the noise generated in the area where it will be used in the vehicle; shorter pyramids are used for high-frequency waves, while longer ones are used for low-frequency waves. In this sense, alternative geometric forms of the insulator (10) of the invention are shown in the figures. Figure 3 shows the view of the insulator (10) of the invention with a wavy form geometry. Figure 4 shows the view of the insulator (10) of the invention with a right angle triangle form geometry. Figure 5 shows the view of the insulator (10) with a triangular pyramid form of the invention. Figure 6 shows the view of the insulator (10) of the invention with a triangle form geometry. The geometric structure of the said insulator (10) can be changed depending on the usage area, sound map and sound frequency to be damped. The geometric forms given in the figures cannot limit the scope of protection of the insulator (10) of the invention.

Changing the lengths of the damping protrusions (11) in accordance with the frequency values exposed has developed the idea of using different geometric shapes for the said insulator (10). In this sense, insulators (10) with different forms can be used in different local places. Another important aspect is that the insulator (10) with different geometric shapes can be produced in the same mold. These dual or multiple insulators (10), arranged according to the sound map, provide maximum acoustic efficiency according to the frequency values where they will be used. The produced insulator (10) has multiple different geometric forms on the same base surface (12) according to low exposure to high sound frequency in certain regions and high sound frequency in certain regions in accordance with the sound map extracted on it. Accordingly, figure 2 shows the view of the insulator (10) of the invention has a pyramidal and triangular form of geometry and has an integrated (dual) structure that allows for damping various heights of sound frequencies. Comparative test results were obtained with known insulation materials produced from different forms and materials. In the table below, the insulator (10) and known materials with different layer structures were given and sound insulation efficiency test was carried out with these materials. (EPDM. Ethylene Propylene Diene Monomer)

According to the measurements made in the Alpha Cabin system, the insulation performance of the above-mentioned materials was compared. Alpha Cabin is a sound absorption coefficient measurement device used for soft flooring materials. The Test sample is placed in the cabinet, and then the sound source inside the cabinet is operated at the center frequency every 1/3 octave, and then the sound absorption coefficient is calculated over the reverberation time of the sound inside the cabinet.

The insulator (10), which was tested and whose acoustic values (sound absorption coefficient) were evaluated, was selected as a square pyramid. A polyurethane injection mold was carried out to create a square pyramid. In this mold, 50 kg/m³ polyurethane material is formed, and the first layer is obtained. The first layer is the integral formation of the said damping protrusions (11) and the said base surface (12). Then, a second layer consisting of a single layer of polyester fiber-based fabric was added to this layer with the application of double-sided tape. The dimensions of the insulator (10) can be changed to suit the usage area with minor changes in the mold design. However, plastic injection molding techniques are used in the production of the mentioned insulator (10), but in addition to these techniques, all thermoplastic production methods such as vacuum forming and inflation can be used. Sound absorption coefficient measurements made in the reverberation cabinet are shown in Figure 7. When the measurement results are examined in detail, it is seen that the proposed square pyramid solution has a superior performance in terms of sound absorption coefficient at 1250 Hz and higher frequencies. D3 and D4 solutions, consisting of polyurethane and EPDM layers, have higher sound absorption coefficients between 630 and 1250 Hz. The felt solutions, D5 and D6, have produced effective results in the low frequency range up to 630 Hz. The application of D2, a single layer of polyurethane, has the worst results in the medium-high frequency range starting at 630 Hz. Here, the reason for the negative result in a single polyurethane layer (D2) is the absence of the mass layer in the solution. Instead, a mass arch mechanism should be created to provide better insulation. In the proposed square pyramid-shaped APLS solution, pyramids have a mass effect due to their shape and provide a high sound absorption coefficient.

Figure 8, on the other hand, shows the value measurements of the loss of sound transmission made in the reverberation cabinet. Since the APLS solution does not show a mass arc effect in a single layer, it has the solution with the lowest sound transmission loss. The D3 and D4 curves offer high sound transmission loss due to the mass effect of a heavy layer in EPDM. However, when the figure is examined in detail, the insulator (10) solution proposed in this study has the highest sound transmission loss in the 2000-6300 Hz range. Accordingly, it is obvious that when a solution needs to be provided within this frequency band (2000-6300 Hz), the solution proposed by the invention should be preferred. In this study, it was observed that the square pyramid solution, which provides the mass-arc system, provides local improvement. Due to the resonance effect, high levels of sound transmission loss have been achieved in a certain frequency range. The insulator (10) of the invention designed in this study activates in the specified frequency band range due to resonance, providing damping.

The insulator (10) of the invention is designed as an acoustic solution for problems such as engine noise, road noise or wind noise. Figure 9 is an exemplary illustration showing the use of the insulator (10) of the invention for sound insulation in different parts of vehicles. First of all, the said insulator (10) aims to present an application that will solve engine noise problems by increasing insulation performance. The firewall -which is a wall between the compartments to separate the engine and passenger components of motor vehicles- is envisaged as a local patch on the instrument panel (15) and does not cause an increase in the total weight of the related parts. In this sense, when the insulator (10) is used as an isolation material patch in accordance with the sound map, it provides serious sound insulation. At the same time, the insulator (10) mentioned in the areas where sound insulation is required in the ceiling coating (14) and floor carpet (16) can be used as a local patch.

Vehicles have disturbing sound sources that can be active at certain frequency range. In this way, instead of changing the weight in the track to dampen a sound source, a significant acoustic efficiency can be achieved with a small patch. For these reasons, the fact that the insulator (10) of the invention can be used as a patch in the areas needed eliminates a serious necessity in the automotive industry.

Claims

1. The invention is an insulator (10) of polymer material, which provides an effective sound damping efficiency in parts such as floor carpets (16), ceiling coverings (14) and instrument panel (15), with thermoplastic production techniques, wherein; it is comprising damping protrusions (11) with geometric forms that will create a mass effect to provide efficient sound insulation at sound frequency values of different heights.

2. An insulator (10) according to Claim 1, wherein; the said damping protrusions (11 ) are in the form of a square pyramid.

3. An insulator (10) according to Claim 1, wherein; the said damping protrusions

(11 ) are in the form of a triangle pyramid.

4. An insulator (10) according to Claim 1, wherein; comprising the damping protrusions (11) with shorter pyramid for high frequency waves and longer pyramid form for low frequency waves, depending on the frequency values of the noise generated in the area where it will be used in the vehicle.

5. An insulator (10) according to Claim 1, wherein; the said damping protrusions

(11 ) are in the form of wavy geometry.

6. An insulator (10) according to Claim 1, wherein; the said damping protrusions (11 ) are in the form of a triangle geometry.

7. An insulator (10) according to Claim 1, wherein; it comprises damping protrusions (11) in different geometric forms depending on the usage area, sound map and sound frequency value that needs to be damped.

8. An insulator (10) according to Claim 1, wherein; it comprises damping projections (11) in more than one different geometric form on the same base surface (12) depending on the exposure to low sound frequency in certain regions, in accordance with the sound map drawn on it.

9. An insulator (10) according to Claim 1, wherein; it comprises the obtaining of it by forming the polymer material in at least one injection mold, designed in a form suitable for the said damping protrusions (11 ).

10. An insulator (10) according to Claim 1, wherein; comprising that it is produced using all thermoplastic production techniques such as plastic injection molding, vacuum forming, blow molding, and so on.

11. An insulator (10) according to Claim 1, wherein; comprising that it can be used as a patch of insulation material without causing an increase in the total weight of the parts in the area in which they are used to dampen disturbing sound sources that can be active in vehicles at certain frequency ranges.

12. An insulator (10) according to Claim 1, wherein; comprising that it can be used in every area that requires sound insulation in the vehicle, such as vehicle floor coverings, engine lower and upper casing, mudguard inner coatings.

13. An insulator (10) according to Claim 1, wherein; comprising that it is made of polypropylene (PP) material with the addition of barium sulfate (BaS04).