KR100474154B1 - Component part with high absorbing effect over a wide frequency range - Google Patents

Abstract

The present invention relates to a lining or shape element for a vehicle, comprising at least one microperforated sheet sound absorbing material, at least one foam and / or nonwoven sound absorbing material, and / or an air gap spaced apart from the reflective wall.

Description

COMPONENT PART WITH HIGH ABSORBING EFFECT OVER A WIDE FREQUENCY RANGE}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to linings or shape elements used in vehicles. [0002] Conventionally, sound absorbing materials formed from fibrous materials used as nonwoven fabrics are known. As the fibers, natural fibers as well as polymer fibers, inorganic or metal fibers may be used. When adhering to a nonwoven fabric, intrinsic and extrinsic fibers and / or polymers or inorganic binders are bonded.

Also known are sound absorbing materials formed from apertured foams formed of polymers, organic materials as well as inorganic materials. The optimal absorption effect of these materials is exhibited in the range of 2000 to 10,000 Hz.

In many technical fields, Helmholtz resonators with different ranges are known for damping atmospheric sound waves, and in the field of automotive construction, the German publications DE 196 15 917 A, DE 196 13 875 A , DE 37 29 765 A and the like. These sound absorbing materials are very space intensive and are conditionally suitable only for automotive structural applications.

DE 197 54 107 C1, which is incorporated by reference in its entirety, and the cited prior art cited in the above document deal with the sound absorption behavior of microperforated parts. The documents deal with a baffle structure formed of a layer of microperforated plastic sheet, a so-called compact sound absorbing material, installed on the ceiling or roof. This microperforated plastic sheet very effectively absorbs sound waves, in particular high frequency sound waves, reaching in a vertical, oblique or oblique direction in space on one or both sides thereof.

On the other hand, if a non-perforated sheet is installed at a distance of several centimeters in parallel for each microperforated sheet, sound absorption of the acoustically active sheet is not improved. This is explained by the fact that an unperforated sheet does not require an echo back wall or any shape gap, such as an air cushion, to exhibit damping action. On the other hand, if the micro-perforated sheet is replaced with an unperforated sheet of the same material, the sound absorption is kept very low. It is well known that sound absorption occurs in a resonator structure in which a mass spring effect can occur. It is not believed that the inventors of this document will be able to give a physical explanation of the sound absorption of the microperforated sheet.

Also known are microperforated sheets and plates capable of filtering a predetermined frequency as a function of hole diameter, wall to sheet, open surface area and sheet thickness due to bores. DE 197 54 107 A describes indoor sound absorbers among such sound absorbers. The document shows that sound absorption is high only over a relatively narrow frequency range. The expansion of sound absorbing bands always leads to significant sound loss, which eventually becomes completely ineffective.

In a two-layer arrangement in which two sheets are superimposed, two frequency bands can be absorbed. Therefore, the sound absorbing band can be expanded without covering the wide range of frequencies required in the automobile field.

In addition, a structure in which a sound absorbing effect is achieved in a sound absorbing material laid under the perforated sound insulating plastic sheet is known, for example, DE 30 18 072 A, DE 41 23 593 A and the like.

DE 41 19 783 A consists of two perforated plates with perforated plates on top of other perforated plates and describes sound absorbing members arranged at a distance from the substrate member and from each other. Between the two sound absorption plates, there is a foam plate. The perforation rate of the sounding side is 50%, and the opposite side of the sounding side is 20%, which far exceeds the value deemed necessary in the present invention.

An object of the present invention is to provide a sound absorbing material which has a sound absorbing effect over the entire frequency band (500 to 5000 Hz) which is a concern in the automobile industry and does not occupy much space for installation.

According to the present invention, the above object is to form a laminated structure of the microperforated sound absorbing material and the nonwoven fabric and / or the foam sound absorbing material and / or the air gap so that the nonwoven and / or the foam sound absorbing material and / or the air gap and the microperforated plate / sheet It is achieved by alternately arranging (microperforated sheet sound absorbing material). Preferably the sound absorbing material has a structure in which one or two microperforated plates / sheets are laminated in two or three nonwoven and / or foam sound absorbing materials or one or two air gaps.

Two types of sound absorbing materials can be coupled by the perforated shape of the microperforated sound absorbing material and the thickness of the nonwoven fabric and / or the foam sound absorbing material and / or the air gap. If it is necessary to determine the specific type of sound absorbing material to be bonded, it will be necessary to distinguish which type to install on the surface in the direction in which the sound enters.

By placing the nonwoven and / or foam sound absorbing material and / or air gap on the sounding side, the properties of the laminate (microperforated plate / sheet-nonwoven and / or foam sound absorbing material and / or air gap) are characterized by the nonwoven fabric being dropped to a predetermined thickness and / or Or only foam absorbers. Depending on the type of nonwoven and / or foam sound absorbing material and / or air gap used, the thickness is in the range of 20 to 40 mm.

When the thickness of the nonwoven and / or foam sound absorbing material and / or air gap is reduced (from 40 mm to 0.3 mm), the microperforated sound absorbing material becomes effective gradually. By selecting the thickness of the nonwoven and / or foam sound absorbing material and / or the air gap, the effects of the two sound absorbing materials can be harmonized with each other. The same principle applies to the case of forming the microperforated sound absorbing material and the nonwoven fabric and / or the foam sound absorbing material and / or the air gap into the multilayer sound absorbing material.

By placing the microperforated sheet sound absorbing material on the sounding side, the combination of the two types of sound absorbing material can be mainly influenced by the open surface area. As the open surface area is increased, the absorbent properties are mainly determined by the nonwoven and / or foam sound absorbing material and / or the air gap. When the open surface area is about 40%, the nonwoven and / or foam sound absorbing material and / or the air gap reach full performance without the microperforated sound absorbing material losing its performance completely.

According to the invention, the at least one microperforated sheet sound absorbing material is preferably laminated with up to 4% open surface area. There is a foam and / or nonwoven sound absorbing material or air gap between the surface and / or plate on the sounding side or between the wall and the final microperforated sheet resonator.

The sound absorption behavior of the sound absorbing material, which represents the surface of the sounding side, influences the sound absorption behavior of the whole system.

Therefore, when the foam and / or nonwoven sound absorbing material is located on the surface of the sounding side, of course, the thickness of the sound absorbing material also affects. When the foam and / or nonwoven sound absorber used in the automotive field is located in the first layer facing towards the sound impingement, the effect of the microperforated sheet sound absorber located in the second layer from the sound source is a foam and / or about 7 mm thick. From the nonwoven sound absorbing material, the effect is reduced to the point that the effect is no longer detected. In this case, the properties of the foam / nonwoven sound absorbing material dominate.

On the other hand, when placing the microperforated sheet sound absorber on the sounding surface, the microperforated sheet sound absorber will dominate the characteristics of the overall system. In this case, the effect of the foam and / or nonwoven sound absorbing material and / or the air gap is very small, and the use of them is not very important.

When placing the microperforated sheet sound absorber in front of the foam and / or nonwoven sound absorber and / or the air gap as viewed from the sound source, the microperforated sheet sound absorber and foam and / or nonwoven sound absorber and / or Results in the engagement of the air gap.

Increasing the number of holes with the same hole diameter, i.e. by increasing the open surface area simply by reducing the hole spacing, the overall system characteristics change to the extent that the properties of the microperforated sheet sound absorbing material change, i.e. Afterwards the effect will change to drastically decrease.

However, increasing the open surface area of the microperforated sheet sound absorber, including additional holes with a surface area of 6 mm ² to 40,000 mm ² (macro-perforated), results in a single structural structure of the microperforated sheet sound absorber (wall distance, sheet thickness, through hole). Spacing) does not exhibit any sound absorbing effect, so that bonding will occur to the foam and / or nonwoven sound absorbing material.

Contrary to expectations, the inability of the two effects to be simply combined can be understood as the increase in one effect leads to the reduction in the other effect. In addition, the frequency band in which the maximum sound absorption effect occurs may be changed to another band or two independent maximum sound absorption values may be formed.

In this regard, it is important to combine these two sound absorbing materials to cover an audible frequency band, and to use a single microperforated sheet sound absorbing material or one foam / non-woven sheet sound absorbing material alone to obtain a predetermined wall distance (10 to 20). mm) cannot cover audible frequency bands.

In this regard, the density of the holes in the microperforation, the arrangement of the holes with respect to the entire surface of the component, and the like do not affect the sound absorption rate as shown in FIG. 3.

In Figures 3A-3C, the components have the same hole diameter and the same open surface area. According to Kundt's tube measurement, they all have approximately the same maximum sound absorption at the same frequency.

Such perforations, on the other hand, can be utilized in designs that take into account particularly prominent areas, for example the interior of a vehicle.

On the other hand, by increasing the surface area of the microperforated sheet sound absorbing material consisting of only microperforation (not macroperforation), the same effect (high efficiency) as in the case of not performing macroperforation can be obtained. Thus, macroperforation still works in foam and / or nonwoven sound absorbers.

For the same open surface area, the effect of the microperforated sheet sound absorbing material is determined by the design of the open surface area. If an increase in the open surface area can be achieved by increasing the number of microperforations, the effects of the two sound absorbing material types are optimal for each open surface area.

However, since the preparation of such a microperforated sheet sound absorbing material is difficult, it is also possible to simultaneously adopt a method of increasing the open surface area by increasing the holes to the stripe structure of the microperforated sound absorbing material and the nonwoven fabric and / or the foam sound absorbing material. The size of the open surface area is within 6-40,000 mm ² .

To achieve spatially uniform sound absorption, the adjacent open surface area should not exceed 40,000 mm ² .

Some typical structures for use in the automotive sector are described below.

The lining or shape element according to the invention is suitable for replacing the sound absorption lining or shape element which is conventionally used in the vehicle field with the sound absorption lining or shape element. In addition, the present invention allows the design of a new member that was not in the prior art in the vehicle field.

Particularly preferred linings or shape elements according to the invention are, for example, wheel housings, hoods, hood linings, engine encapsulation, heat transfer plates, vehicle shields, transmission tunnel linings, dashboards, vehicle seats, Seatbacks, armrests, steering wheel, floor carpets, in particular carpet covering the entire floor, roof linings, pillar linings, door linings, passenger compartment linings, cargo compartments, rear compartments, heat shields and / or trunk linings.

1 shows a transmission tunnel lining comprising microperforated sheet sound absorbers with different pore sizes. 2 shows a loop lining designed according to the present invention.

Therefore, according to the present invention, not only the microperforated sheet sound absorbing material distanced from the reflection wall, but also several microperforated sheet sound absorbing materials can be provided on the upper surface thereof alternately to be provided with a lining or a shape element for a transportation means, respectively. Can be.

The sound absorption characteristics of the lining or shape element in the vehicle field according to the present invention are determined by the number of microperforated sheet sound absorbing materials, the ratio of the hole area, the hole spacing and the hole diameter.

Therefore, the lining or shape element of the particularly preferred vehicle field according to the present invention is such that the microperforated sheet sound absorbing material has a ratio of the hole area microperforated to 0.2 to 4%, in particular 0.3 to 2% depending on the surface area of the microperforated sheet sound absorbing material. It features. Of course, they can also be designed with the same or different hole area ratios. Holes can be formed in the microperforated sheet sound absorbing material in any shape by conventional known methods, for example, by punching or laser irradiation.

If the hole area ratio is set too low, there is little or no sound absorption effect, while if the hole area ratio is set too high, the sound absorption effect is reduced.

Linings or shaped elements in the field of vehicles according to the invention have at least one diameter in the range of 0.05 to 2 mm, in particular in the range of 0.1 to 0.8 mm, in the microperforated sheet sound absorbing material, and in the range of 1 to 3 mm, especially 2 to 20 mm in the sheet sound absorbing material. One or more hole spacings within the range.

The pore size or pore spacing in the second or less added microperforated sheet sound absorbing material is the same scale as in the first microperforated sheet sound absorbing material, but is distinguished by an absolute size.

Thus, for example, conventional components inside a vehicle, in particular those placed in front of an empty space, can all be designed in a microperforated configuration. For example, laser irradiation can make holes irreversible to all known materials.

In order to have a sound absorbing effect, according to the invention, a visible area slightly larger in diameter, for example in the range of 0.5 to 2 mm, for example a roof lining or rear compartment of a car or a roof lining or handrail of an airplane It is preferable to form in. In particular, it is preferable to form a hole having a diameter of 0.05 to 0.5 mm according to the present invention in the near region visible to the eye. Holes with a diameter of 0.3 to 0.1 mm cannot be visually recognized as holes in the surface or structures of the surface. Thus, for example, vehicle seats, seatbacks, armrests, side portions of seats, dashboards and side and door linings may also have a microperforated surface according to the invention.

In the engine section, many parts are arranged in front of the empty space, and there is no need to surround this empty space. Heat shields and other high temperature components on the engine's exhaust can also be microdrilled. Almost all internal linings of the engine compartment, such as engine encapsulation or hood linings, can be microperforated design. In this regard, when the lining or the shape element of the present invention is directly mounted on the surface of the vehicle or engine, particularly good sound absorbing effect can be achieved at the noise generating point.

It is well known that the mutual wall distance between the sheet sound absorbing materials adversely affects the sound absorbing ability. In a preferred embodiment of the present invention, the mutual distance of the microperforated sheet sound absorbing material is constant when there are two or more microperforated sheet sound absorbing materials. They are thus in parallel or optionally plane paralle layers. Since plane parallelism is not desirable for a vehicle structure, in a more advantageous embodiment of the present invention, the mutual distance of the microperforated sheet sound absorbing material is variable when there are two or more microperforated sheet sound absorbing materials. It can also be understood to mean that for example, curves with different radii of curvature are facing, or convex or concave layers face each other.

According to the present invention, there is no need to fill the distance between each microperforated sheet sound absorbing material with a damping material. If there is a damping material, the damping material may be chosen, in particular, from foamed and nonwoven fabrics with open holes made of plastic or metal. The microperforated sheet sound absorbing material may be partially or completely filled with a desired material.

Thus, using the present invention, it is possible to provide a lining or shape element for use in vehicles, in particular automobiles, for example passenger cars, trucks, buses, motorcycles, tracked vehicles, in particular locomotive engines, wagons, trams and ships and aircraft. have.

Claims (15)

At least one microperforated sheet sound absorbing material having a pore area ratio of 0.2 to 4%, The microperforation holes of the microperforated sheet sound absorbing material have one or more diameters in the range of 0.05 to 2 mm, one or more hole spacings in the range of 1 to 20 mm, Lining or shape element for a vehicle comprising at least one foam and / or nonwoven sound absorbing material spaced apart from the reflective wall by a predetermined distance. The method of claim 1, The lining or shape element may be a wheel housing, hood, hood lining, engine encapsulation, heat transfer plate, vehicle shield, transmission tunnel lining, dashboard, vehicle seat, seatback, armrest, A lining comprising a steering wheel, floor carpet, in particular a carpet covering the entire floor, roof lining, pillar lining, door lining, passenger compartment lining, cargo compartment, back compartment, heat shield and / or trunk lining Or shape element. The method of claim 1, The microperforated sheet sound absorbing material has a pore area ratio of 0.3 to 2% based on the surface area of the sound absorbing material. The method of claim 1, The hole of the microperforated sheet sound absorbing material for microperforation has at least one diameter in the range of 0.1 to 0.8 mm, and at least one hole spacing in the range of 1 to 3 mm. The method of claim 1, A lining or shape element comprising a plurality of microperforated sheet sound absorbing materials, particularly a plurality of microperforated sheet sound absorbing materials, each having a different pore diameter, and each of the microperforated sheet sound absorbing materials having a different hole spacing. The method according to any one of claims 1 to 5, The microperforated sheet sound absorbing material is a lining or shape element, characterized in that the sound absorbing material has a plurality of holes, one or more hole spacing is in the range of 2 to 20 mm. The method according to any one of claims 1 to 5, Lining or shape element, characterized in that the macroperforated adjacent surface area is 6 to 40,000 mm ² . The method according to any one of claims 1 to 5, The microperforated holes are uniformly distributed over the surface of the sound absorbing material or are concentrated in the same hole diameter and the same open surface area in one or several places of the sound absorbing material. The method of claim 1, The layer thickness of the microperforated sheet sound absorbing material is 0.2 to 5 mm, in particular 0.2 to 2 mm. The method of claim 1, The material of the microperforated sheet sound absorbing material may include plastic, leather, cork, wood, rubber, textile, glass, and / or metal. Lining or shape element characterized in. The method of claim 1, The device is a multi-layered, the lining or shape device, characterized in that the layers are made of the same material or each layer is made of a different material. The method of claim 1, Lining or shape element, characterized in that the mutual distance between the microperforated sheet sound absorbing material is constant in the presence of at least three microperforated sheet sound absorbing material. The method of claim 1, Lining or shape element, characterized in that the mutual distance between the microperforated sheet sound absorbing material is different when there are at least three microperforated sheet sound absorbing material. The method of claim 1, Lining or shape element, characterized in that the thickness of the material, hole spacing and hole diameter is variable over the device. The method according to any one of claims 1 to 5, The vehicle is a lining or shape element, characterized in that it comprises a car, in particular a car, a truck, a bus, a motor cycle, a tracked vehicle, in particular a locomotive engine, a wagon and a streetcar, and a ship and an aircraft.