DE102014103417A1 - Three-layer acoustic isolator - Google Patents

Abstract

A three-layer acoustic insulation system comprises an acoustic decoupling layer, an acoustic barrier film layer that is connected to the decoupling layer, and a microfiber acoustic absorption layer that is connected to one side of the barrier film layer, which is opposite the acoustic decoupling layer. The acoustic decoupling layer is arranged in direct contact with a vehicle component and takes on the geometry of the vehicle component. The acoustic absorption layer is arranged on the side of the vehicle component that faces the vehicle interior.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of US Provisional Application No. 61 / 787,068, filed Mar. 15, 2013. The entire disclosure of this application is hereby incorporated by reference.

TERRITORY

The present invention relates to acoustic damping systems used in automobiles, including light passenger vehicles and light trucks.

BACKGROUND

This section contains background information relating to the present disclosure, this background information not necessarily being prior art.

Vehicle manufacturers have relied in the past on two-ply foams and / or "shoddy" material that has been constructed for lightweight constructions having thicknesses of about one-quarter of an inch to several inches, such as for engine fire walls and the transmission tunnel to vehicle and To dampen road noises that enter the vehicle interior. When fuel economy was not important and engines with high horsepower were used, the damping systems could be thicker, increasing their weight and thus their noise damping capability without significantly affecting vehicle performance. With the increase in "miles per gallon" fuel rates and the reduction in horsepower, the allowable damping system weights have necessarily been reduced, forcing manufacturers of damping systems to use lighter materials. The damping system weight was subsequently reduced, but as a compromise with the achieved acoustic attenuation. It has therefore become desirable to provide acoustic damping systems that provide damping values that are similar to the known thicker / heavier designs while providing the benefits of reduced weight.

SUMMARY

This section provides a general summary of the disclosure and is not intended to be an exhaustive disclosure of the full scope or all features.

In several aspects, a three-layer acoustic isolation system includes an acoustic decoupling layer. An acoustic barrier film layer is bonded to the decoupling layer. A microfiber acoustic absorption layer is bonded to the barrier film layer and is oppositely oriented with respect to the acoustic decoupling layer.

In accordance with the other aspects, the acoustic decoupling layer is positioned in direct contact with a vehicle component and replicates the geometry of the vehicle component, the acoustic absorption layer being on the vehicle component facing the vehicle interior.

Further fields of application emerge from the description provided here. The description and specific examples in this summary are provided by way of illustration only and are not intended to limit the scope of the present disclosure.

DRAWINGS

The drawings described herein are merely illustrative of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.

1 FIG. 12 is a top perspective view of a three-layer acoustic isolation system of the present disclosure; FIG.

2 is a sectional view from the front along the section 2 of 1 ;

3 is a plot of frequency and absorption coefficient for the three-layer acoustic insulation system of 1 ;

4 FIG. 12 is a graph of frequency and transmission loss of the three-layer acoustic isolation system of FIG 1 ,

Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.

DETAILED DESCRIPTION

Exemplary embodiments will now be described in more detail with reference to the accompanying drawings.

Referring to the 1 includes a three-layer acoustic insulation system 10 , one Acoustic decoupling layer 12 , an acoustic barrier layer 14 made of a plastic film, with the acoustic decoupling layer 12 connected, and a microfiber acoustic absorption layer 16 that with the acoustic barrier layer 14 connected is. The Microfiber Acoustic Absorption Layer 16 is with respect to the acoustic decoupling layer 12 on the opposite side of the acoustic barrier layer 14 intended. The acoustic decoupling layer 12 may contain material such as polyester fibers, cotton and / or a foam material. The acoustic barrier layer 14 is a film of a polymeric material, such as polyethylene, EVA, or any other thermoplastic or thermoset material. The Microfiber Acoustic Absorption Layer 16 contains polypropylene microfibers, which may be limited by an acoustic grille on one or both sides to strengthen and protect the microfibers. According to several aspects, the three-layer microfiber acoustic absorption layer 16 a commercially available product, for example, referred to as AutoZorb ^™ available from AIMs; SonoZorb ^™ available from GDC, Inc.; or Thinsulate ^™ available from 3M Corporation. The use of the aforementioned three layers in the construction of the acoustic insulation system 10 may provide a thermoformed acoustic barrier assembly. The layers may be bonded together by heat and pressure, by gluing, by adhesive, by fastening, or by other suitable means.

Referring to the 2 has the acoustic decoupling layer 12 a page 18 that are in direct contact with a surface 20 a vehicle component 22 is arranged, such as an engine fire wall, a transmission tunnel or a vehicle body panel. The vehicle component 22 is between a noise source 24 , such as the vehicle engine, and a passenger compartment 26 arranged, wherein the acoustic performance criteria are predetermined by the vehicle manufacturer. The noise source 24 may include, but is not limited to, road noise, tire noise, and / or wind noise, or a combination of these noise sources. The vehicle component 22 is shown as a flat metal panel component for ease of illustration; however, the vehicle component can 22 have any geometric shape, including a plane, curved, rough, wavy shape or the like, or may be a free form. The material of the acoustic decoupling layer 12 is selected and provided for the shape of the vehicle component 22 to accept and reproduce and retain this shape and thus as an air gap between the vehicle component 22 and the acoustic barrier layer 14 to act. A thickness "A" of the acoustic decoupling layer 12 may range from about 2 mm to about 40 mm, and may vary across the width and length of the acoustic decoupling layer 12 vary to accommodate compression due to local space constraints, such as ventilation system ducts, electrical cable routes, and the like.

With further reference to the 2 is an opposite second page 28 the acoustic decoupling layer 12 with a first surface 30 the acoustic barrier layer 14 connected, for example by bonding. The acoustic barrier layer 14 can be distracted to the shape of the vehicle component 22 replicate. The hardest components of the three-layer acoustic insulation system 10 are the acoustic decoupling layer 12 and the acoustic barrier layer 14 , The acoustic barrier layer 14 may also be thermoformed to conform to a contour of the vehicle component 22 to be adapted. The acoustic barrier layer 14 is nominally the thinnest layer of the three-layer acoustic insulation system 10 with a nominal thickness (B) of about 0.4 mm but may be in a range of about 0.03 to about 1 mm.

An oppositely directed second surface 32 the acoustic barrier layer 14 can be in direct contact with a page 34 the Microfiber Acoustic Absorption Layer 16 be arranged. The page 34 may be an area of a layer of polypropylene microfibers 36 define. The page 34 can also be a surface of a grid 38 define the polypropylene microfibers according to further aspects 36 completely surrounded. The Microfiber Acoustic Absorption Layer 16 has a thickness "C" which may range from 5mm to about 25mm. The polypropylene microfibers 36 create layers with tortuous paths that block the passage of air through the microfiber acoustic absorption layer 16 while converting energy from the airflow into thermal energy and thereby absorbing some of the sound energy of the noise source.

Reference is now made to the 3 and again on the 1 and 2 , Exemplary OEM standard absorption targets for a 20mm thick (for a lightweight system) acoustic isolation system require a very high power range. A first target curve 40 represents a 20 mm light (1200 gsm to 2400 gsm) absorption target representing very good performance and a second target curve 42 represents a 20 mm light absorption target representing acceptable performance. A three-layer acoustic insulation system 44 with a micro-denier rider layer (microfiber acoustic absorption layer 16 ) with a 18 mm thickness and air flow resistance (AFR) of 950 Rayls delivers performance within an acceptable range. A three-layer acoustic insulation system 46 with a micro-denier rider layer (microfiber acoustic absorption layer 16 ) of 20mm thickness and an AFR of 1100 Rayls also provides performance within acceptable levels.

It will now be on the 4 and again on the 1 and 2 Referenced. Exemplary OEM sound transmission loss objectives require the use of at least one foil / barrier within an acoustic composite. A first target curve 48 represents a 25 mm high-range target and a second curve 50 represents a 25 mm thick low range target that differs by 2 db. The target barrier performance of a three-layer acoustic isolation system 52 with a 2000 gsm composite weight shows an acoustic barrier layer 14 with a film thickness of 0.5 mm, and a microfiber acoustic absorption layer 16 with a thickness of 18 mm exceeds the target performance. The target barrier performance of a three-layer acoustic insulation layer 54 with a composite weight of 1800 gsm, which is an acoustic barrier layer 14 with a film thickness of 0.25 mm and a microfiber acoustic absorption layer 16 indicating with a thickness of 18 mm, also exceeds the target performance. The system stiffness is in the lower two layers, the acoustic decoupling layer 12 and the acoustic barrier film layer 14 achieved.

The three-ply acoustic isolation systems of the present disclosure may also be altered by incorporating multiple types of material and achieving a total system or composite weight of about 2000 gsm. For example, the microfibers in the microfiber acoustic absorption layer 16 PP, PET and / or PET / PP (up to 2 denier). That for the acoustic barrier layer 14 used material may be PE, PP, PVC, EVA and / or any thermoplastic or thermosetting material. The material of the decoupling layer 12 can be any malleable fiber or moldable foam.

The system of the present disclosure provides several advantages, for example, providing a multi-layer system that uses high efficiency microfibers with light barriers and moldable fibers. Known acoustic barrier constructions are designed either in the direction of acoustic absorption or in the direction of acoustic transmission loss, so that there is no balanced performance between acoustic absorption and transmission loss. The "tunability" of the construction of the present disclosure allows various performance goals to be achieved. The microfibers are not self-supporting; therefore, the structure of the system comes from the barrier film and the moldable fibers. This provides superior acoustic absorption on the vehicle occupant side of a vehicle and noise reduction due to transmission loss due to the decoupled barrier film. The "tunability" is provided by the system, which provides several different ways to achieve OEM acoustic target values by changing fibers, foils and thicknesses of any or all three layers.

Exemplary embodiments are illustrated so that this disclosure is exhaustive and fully describes the scope of a person skilled in the art. Many specific details are set forth, such as examples of specific components, devices, and methods to provide a thorough understanding of the embodiments of the present disclosure. It will be understood by those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many other forms, and that they should not be construed as limiting the scope of the disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms "one" and "the one" are intended to encompass the plural forms unless the content clearly dictates otherwise. The terms "comprising", "having", "comprising" and "having" are inclusive and therefore specify the presence of specified features, numbers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or several other features, numbers, steps, operations, elements, components, and / or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their execution in the order indicated, as discussed or illustrated, unless an order of execution is specifically indicated. It is also understood that additional or alternative steps may be used.

When an element or layer is referred to as "on," "engaged with," "connected to," or "coupled with" another element or layer, it may be directly on, engaged in, connected to or coupled to the other element or layer the other layer, or intervening elements or layers may be present. Conversely, however, when an element is referred to as "directly on," "directly engaged with," "directly connected to," or "directly coupled to" another element or layer, there must be no intervening element or layer. Other words used to describe the relationship between elements should be interpreted in the same way (eg, "between" versus "directly in between," "adjacent" versus "directly adjacent," etc.). The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

Although the terms first, second, third, etc., may be used herein to describe various elements, components, regions, layers, and / or sections, these elements, components, regions, layers, and / or sections should not be limited by these terms , These terms are used alone to delineate one element, component, region, layer, section from another region, layer, or section. Terms such as "first," "second," and other numerical terms are used herein to imply no order or ranking unless clearly indicated in context. Thus, a first element, component, region, layer or portion as discussed below may also be referred to as a second element, component, region, layer or portion without departing from the scope of the present teachings of the exemplary embodiments.

Relative spatial terms such as "inner," "outer," "below," "above," "lower," "upper," or the like, are used herein to simplify the description of the relationship of one element or feature to another element or feature describe as shown in the figures. Relative spatial terms may be provided to indicate different orientations of the device in use or operation in addition to the orientation shown in the figures. For example, if the device in the figures is turned over, elements described as "below" or "below" other elements or features would then be aligned with "above" the other elements or features. Thus, the exemplary term "under" includes both an orientation above and below. The device may be otherwise oriented (rotated 90 ° or other orientations) and the relative spatial terms used herein interpreted accordingly.

The foregoing description of the embodiments has been provided for the purpose of explanation and description. It is not intended to conclude or limit the disclosure. Particular elements or features of a particular embodiment are generally not limited to this particular embodiment, but may be substituted where applicable, and may be used in a selected embodiment, even if not specifically shown or described. The same can also be varied in different ways. Such variations are not to be considered as variations that are outside the disclosure, and all such modifications are intended to be within the scope of the disclosure.

Claims (8)

Three-layer acoustic insulation system with: an acoustic decoupling layer; an acoustic barrier foil layer bonded to the decoupling layer; and a microfiber acoustic absorption layer bonded to the barrier film layer and oppositely oriented with respect to the acoustic decoupling layer. The three-layer acoustic insulation system of claim 1, wherein the acoustic decoupling layer is selected from materials comprising: synthetic fibers, cotton and / or foam material. The three-layer acoustic insulation system of claim 1, wherein the barrier layer is a sheet of elastomeric material, wherein the material is polyethylene, EVA, a thermoplastic material, or a thermoset material. The three-layer acoustic insulation system of claim 1, wherein the acoustic absorption layer comprises polypropylene or thermoplastic microfibers delimited by an acoustic grid or face on at least one side. The three-layer acoustic insulation system of claim 1, wherein a thickness of the acoustic absorption layer is in the range of about 5 mm to about 25 mm. The three-layer acoustic insulation system of claim 1, wherein a thickness of the acoustic barrier layer is in the range of about 0.03 to about 1 mm. The three-layer acoustic isolation system of claim 1, wherein the acoustic decoupling layer is disposed in direct contact with a vehicle component and assumes the geometry of the vehicle component. The three-layer acoustic insulation system of claim 1, wherein the acoustic absorption layer comprises the side of the vehicle component is arranged, which faces the vehicle interior.

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