DE10022902A1 - Component with high absorptive effect over a wide frequency range - Google Patents

Abstract

The invention relates to a covering element or molded element for means of transport that comprises at least one micro-perforated film absorber, at least one absorber that consists of a foamed or nonwoven material and/or a clearance at a distance to a reverberant wall.

Description

The invention relates to a trim or molded element for Transportation.

In the prior art, absorbers made of fiber material are known can be used as fleece components. The fibers come alongside Natural fibers polymeric fibers inorganic or metallic fibers for use. A binding to the components is done by a Linking via your own and foreign fibers and / or through a binder which is polymeric or inorganic in nature can be.

Furthermore, absorbers made of open-pore foams made of polymer known organic as well as inorganic material. The optimal one The absorption effect of such materials lies in a frequency range ranging from 2000-10 000 Hz.  

The use of is from the different areas of technology Helmholz resonators of various dimensions for damping airborne sound is known for the field of motor vehicle construction be representative of the published patent application DE 196 15 917 A, DE 196 13 875 A and DE 37 29 765 A pointed out. This absorber About are very space-intensive and only be for the automotive sector really suitable.

In DE 197 54 107 C1 and the prior art referenced here, to which full reference is made to absorption behavior of microperforated components examined. In the above Fonts are built up layered from microperforated foils Baffle structures investigated as so-called compact absorbers depends on a ceiling or roof. The micro-perforated Fo lien are suitable, one-sided or both-sided, vertical, oblique or grazing sound waves from the room, especially at absorb higher frequencies, very effectively.

If you also parallel for a few centimeters for each micro-perforated film a further, non-perforated film tension, the absorption of the acoustically effective film improves Not. This is explained by the fact that the latter to unfold their Damping effect neither a reverberant rear wall, nor a like always designed cavity in between needed as an air cushion. If you replace the micro-perforated with non-perforated foils of the same material, there is only very little absorption left. Sound absorption is known to come from a reso nator arrangement occurs where the mass-spring effect comes into play is coming. A physical explanation for the sound absorption of the microperforated films is from the inventors of the above Documentation not considered possible.  

Micro-perforated foils and plates are also known, which are described in Ab dependence on the hole diameter, the distance of the film from the Wall, the area that is open through the holes and the foil di can filter out defined frequencies. In DE 197 54 107 A is such a sound absorber for the area of rooms described ben. Here the effect occurs that a high absorption only over egg a relatively narrow frequency range can be achieved. A ver Widening of the absorption range is always considerable Chen loss of absorption connected to then completely ineffective to become sam.

In a two-layer arrangement, in which two foils in a row two frequency ranges can be absorbed. This makes widening possible without that in the automobile reach the necessary width.

There are also known structures where there is a soundproof surface is perforated for an absorptive effect of the to reach the underlying absorber, see for example DE 30 18 072 A, DE 41 23 593 A.

DE 41 19 783 A describes a soundproofing element ches consists of two stacked perforated plates that are arranged at a distance from the support element and from one another. There is a foam plate between the two perforated plates. The proportion of holes on the side facing the sound is 50%, that of the The side facing away from the sound is 20%, which is significantly higher the values considered necessary here.

The object of the invention is to provide an absorber which the entire area of Fre  sequences (from 500 Hz to 5000 Hz) has an absorptive effect and a clot space is required.

According to the invention the object is achieved in that a layer wise construction of micro-perforated absorbers and fleece and / or Foam absorber and / or air gap is provided in the manner that there is a fleece and / or foam absorber or a hollow space (air gap) with a micro-perforated plate / foil (micro-perforated foil absorber) alternates. Ab are preferred sorber constructed so that one or two microperforated plates / foils in connection with two or three fleece and / or foam absorbers bern or one or two cavities are arranged one above the other.

Due to the hole design of the micro-perforated absorber and the thickness the fleece and / or foam absorber and / or air gap a coupling of both types of absorbers is achieved. When considering the A distinction must be made between the coupling of the individual absorber types, which type is in the direction of sound entry on the surface finds.

There is a fleece and / or foam absorber and / or Air gap on the side facing the sound will be from one thickness matched the properties of the composite (microperforated Plate / foil fleece and / or foam absorber and / or air gap) alone through the fleece and / or foam absorber Right. Depending on the fleece used and / or Foam absorber and / or air gap is 20-40 mm.

With decreasing thickness (40 mm-0.3 mm) of the fleece and / or The micro-hole absorber acts on foam absorber and / or air gap With. By choosing the thickness of fleece and / or foam  sorting and / or air gap can affect the effect of both absorbers be coordinated. The same applies to a subsequent one Location of micro-hole absorber and fleece and / or foam absorber over and / or air gap in multi-layer absorbers.

The micro-perforated film absorber is located on the sound train on the opposite side is a coupling of both types of absorbers in the first Realize line through the open area. With increasing open The absorption behavior through the fleece and / or Foam absorber and / or air gap determined. With an open Area of va. The fleece and / or foam reaches 40% sorber and / or air gap its full effect without the Micro-hole absorber loses its effect completely.

According to the invention, one or more microperforated foils are sorber with an open area of preferably up to 4% layer arranged wisely. Surface on the side facing the sound and / or between the plates or between the wall and the last one micro-perforated film resonator is a foam and / or fleece absorber or air.

Depending on which absorber the surface of the sound-facing Side, whose absorption behavior dominates the Absorpti behavior of the overall system.

It plays in the event that a foam and / or fleece absorber Of course, the thickness of the absorber also lies above the surface a role. Is a foam and / or fleece absorber, as in Automotive use, in the first position to the sound becomes the effect of one starting from the sound source in the second Layer of microperforated foil absorbers, from a thickness of Reduce approx. 7 mm of the foam and / or fleece absorber as much  annoyed that its effects can hardly be proven. It dominates the property profile of the foam / fleece absorber.

The micro-perforated film absorber is on the other side The surface of the side facing the sound dominates the egg property picture of the overall system. The effect of the foam and / or fleece absorber and / or air gap is extremely low and its use has no practical meaning.

By introducing additional open areas into the micro perforated foil absorber, takes place when the microperforated foil absorber Above the foam and / or fleece absorber and / or air gap seen from the sound source, a coupling of mikroge perforated foil absorber and foam and / or fleece absorber and / or air gap instead.

If the open area is increased solely by using the same Hole diameter the number of holes is increased, d. H. the Hole spacing decreases, so the properties of the Overall system to the extent that the properties of the micro Change perforated film absorber, d. H. after passing a Ma ximums the effect drops sharply.

However, if the open area in the micro-perforated film absorber is increased by adding additional holes with an area of (6 mm ² -40 000 mm ² ) (macro perforation) that are sufficient for the given structure of the micro-perforated film absorber (wall distance, film thickness, hole spacing) ) show no absorption effect, there is a coupling to the foam and / or fleece absorber.

Contrary to expectations, there was no simple overlay given the effects in such a way that one effect increases and the other other decreases. Rather, there is a shift in ma ximal absorption in another frequency range or it can two separate absorption maxima are established.

It is important in this context that through this coupling the absorber is the frequency range audible to the human ear can be covered as it is for a given wall distance (10-20 mm) through a micro-perforated film absorber or a Foam / fleece absorbers alone can never be achieved.

It is important in this context that with an average concentration of the holes for the micro-perforation, the arrangement of the holes on the entire surface of the component does not determine the absorption ratio, as is shown in FIG. 3.

In Fig. 3a) to c), the components same hole diameters and the same open area have. For measurements in the Kundt tube, they deliver almost the same absorption maximum at the same frequency.

On the one hand, you can use this perforation specifically for the design, specifically in these areas, which are used in the field of vision, for example in Interior, lying.

On the other hand, the areas of the micro-perforated film absorber bers that only have micro perforations (no macro perforations) be increased so that an effect arises as if none Macro perforations are present (high efficiency). The macro hole then delivers the effect of the foam and / or fleece absorber bers.  

The effect of the micro-perforated film absorber is the same open area determined by the design of the open area. If the open area is increased by increasing the The number of microholes reached is the effect of both types of absorbers ideal for any open area.

However, the manufacture of such micro-perforated film absorbers is agile, so that an enlargement of the open area by enlarging the holes up to a strip-shaped construction of micro-hole absorber and fleece and / or foam absorber can be used side by side. The size of the open areas is in the range from 6 to 40,000 mm ² .

In order to achieve a spatially homogeneous absorption, the connected open area must not exceed a value of 40,000 mm ² .

The following are some typical structures, such as those in Automo find application.

The paneling or molded elements according to the invention are ge suitable, not previously used sound absorber in the prior art covering or form elements in the vehicle area to replace sound absorbing cladding or form elements. In addition, the present invention allows a new design he, previously in the prior art elements not present in driving tools area.

Particularly preferred cladding or form elements in the sense the present. Invention include wheelhouses, Mo hoods, hood cladding, engine encapsulation, heat  baffles, vehicle protection shields, transmission tunnel covers, Dashboards, vehicle seats, backrests, armrests, steering wheels the, floor coverings, especially carpets, headliners, columns linings, door linings, passenger compartment linings, Ge luggage racks, hat racks, heat signs and / or trunk liners fertilize.

In Fig. 1, a transmission tunnel cladding is shown, which comprises different hole sizes in the micro-perforated film absorber. Fig. 2 shows a headliner, which is designed with the help of the present invention.

With the help of the present invention it is thus possible to sell to provide form or form elements for means of transport len, not just a micro-perforated film absorber at a distance facing the reverberant wall, but also several micro-perforated film absorbers one above the other, each with a a certain distance from each other.

The acoustic properties of the invention Cladding or form elements in the vehicle area are in the we significantly through the number of micro-perforated film absorbers, the proportion of the perforated area, the spacing between the holes and the diameter of the holes certainly.

Are therefore particularly preferred for the purposes of the present invention Cladding or molded elements in the vehicle area, which thereby are characterized in that the micro-perforated film absorber Perforated area with microperforation of 0.2 to 4%, in particular 0.3 to 2%, based on the area of the micro-perforated film absorber bers. It is of course possible to do this in each case with a different or the same proportion of perforations  shape. The holes can be according to the prior art known methods, for example by punching or laser irradiation with any geometry in the micro-perforated film absorber be introduced.

If the proportion of perforated area is chosen too low, a sound absorber is used there is no or insufficient effect the, while on the other hand if the perforated surface is too high proportion of the sound-absorbing effect diminishes again.

Preferably, the trim or cover according to the invention Molded elements in the vehicle area holes in a microperforated Foil absorber with one or more diameters in the area from 0.05 mm to 2 mm, in particular 0.01 mm to 0.8 mm and egg NEN or more hole spacing in the film absorber in the area from 1 mm to 3 mm, in particular 2 mm to 20 mm.

The hole sizes and hole spacing in a second or more subsequent micro-perforated film absorbers are in the same Order of magnitude as in the first micro-perforated film absorber, however differ in absolute size.

For example, it is possible to use all common components of the In nenraums of means of transport, especially those in front of hollow rooms are arranged to train in the micro-perforated construction the. For example, using laser radiation can be irreversible Make holes in all known materials.

In order to be able to absorb sound, it is in the sense of the present preferred invention preferred, the holes in the more distant viewing area, for example in the vehicle headlining or the parcel shelf in the motor vehicle stuff, the sky or the hand luggage rack on a plane with an egg  nem larger diameter, for example in the range of 0.5 mm up to 2 mm. In the close range, which is particularly true optically is taken, it is in the sense of the present invention before pulls holes with a diameter of 0.05 to 0.5 mm ready put. For holes with diameters in the range from 0.3 to 0.1 mm diameter the viewer takes the holes in the surface optically no longer true or considers it a structuring. So For example, vehicle seats, backrests, armrests, Side parts of the seats, dashboard and side and door trim micro-perforated surfaces in the sense of the present Er have invention.

In the engine compartment, many parts are arranged in front of cavities, the Cavities do not have to be closed. The heat shields over exhaust manifolds and other hot parts of the engine also be micro-perforated. It is also possible to prak table the entire interior lining of the engine compartment, such as engine cover encapsulation or hood cladding in the micro perforation equipment. Are surfaces of the vehicle or of the engine directly in the sense of the present invention, a particularly good sound absorption is possibly on site of sound development achievable.

As is known, the wall distance between the foils affects absorb sound absorption among each other. In a preferred embodiment of the present invention is Ab stood the micro-perforated film absorber in the presence of more as 2 micro-perforated film absorbers with each other constant. Here it is therefore parallel, possibly plane-parallel Layers. As a rule, plane parallelism is not in vehicle construction is desired, there is a further preferred embodiment of the present invention in that the distance of the microperforated  Foil absorber in the presence of more than 2 micro-perforated fo lienabsorber is different from each other. Below is further to understand that, for example, curved, convex or concave Layers with different radii of curvature against each other survive.

In the sense of the present invention, it is not absolutely necessary Lich that the space between the respective microperforated Foil absorbers with each other with a damping material is filling. In the event of the presence of a damping material this is particularly preferably selected from open-pore foam fabric, in particular made of plastic or metal, and of fleece. Here it is possible to determine the distance or distances between the microperforated foils partially or completely with each other with the ge fill in the desired material.

With the help of the present invention it is thus possible to sell Form or elements for vehicles, especially motor vehicles witness, for example passenger cars, trucks, buses se, motorcycles, rail vehicles, especially Loko motifs, wagons, and trams as well as for ships and flights to provide witnesses.

Claims (15)

1. Comprehensive covering or form element for means of transport at least one micro-perforated film absorber, at least one Foam and / or fleece absorber and / or air gap in spatial distance from a reverberant wall. 2. cladding or molded element according to claim 1, characterized ge indicates that there are wheel arches, bonnets, bonnet coverings applications, engine encapsulation, heat conducting plates, vehicle protection shields, transmission tunnel coverings, dashboards, vehicle sit ze, backrests, armrests, steering wheels, flooring, in particular Carpets, headlining, pillar cladding, door cladding, Passenger compartment linings, luggage racks, hat racks, heat shields which includes and / or trunk linings. 3. cladding or molded element according to claim 1, characterized ge indicates that the micro-perforated film absorber has a perforated surface Chen fraction of 0.2 to 4%, in particular 0.3 to 2%, based on the area of the absorber. 4. cladding or molded element according to claim 1, characterized ge indicates that the holes of the microperforated film absorber for the microperforation has one or more diameters in the area from 0.05 mm to 2 mm, in particular 0.1 mm to 0.8 mm and one or several hole spacings in the range from 1 mm to 3 mm sen. 5. cladding or molded element according to claim 1, characterized ge indicates that there are several micro-perforated film absorbers, esp each with a different hole diameter per micro  perforated foil absorber and each different hole spacing per micro-perforated film absorber. 6. Cladding or form element according to one or more of claims 3 to 5, characterized in that the microge perforated foil absorber a perforated area with microperforation from 0.2 to 4% and a perforation area with macro perforation of 2 up to 20%, based on the area of the absorber. 7. cladding or molded element according to one or more of claims 1 to 6, characterized in that the coherent surface for a macro perforation is 6 mm ² to 40 000 ² . 8. Cladding or form element according to one or more of claims 1 to 7, characterized in that the holes for micro perforation homogeneous over the surface of the absorber are distributed, or with the same hole diameter and the same open Concentrate the area at one or more points of the absorber. 9. cladding or molded element according to claim 1, characterized ge indicates that the layer thickness of a microperforated sorbers is 0.2 mm to 5 mm, in particular 0.2 mm to 2 mm. 10. cladding or molded element according to claim 1, characterized ge indicates that the material of the micro-perforated film absorber Plastics, leather, cork, wood, rubber, textiles, glass and / or me talle includes. 11. cladding or molded element according to claim 1, characterized ge indicates that the element is multilayered from the same material consists or the individual layers of different materia lien exist.   12. cladding or molded element according to claim 1, characterized ge indicates that the distance between the micro-perforated film absorbers in the presence of at least 3 microperforated sheets sorber among themselves is constant. 13. cladding or molded element according to claim 1, characterized ge indicates that the distance between the micro-perforated film absorbers in the presence of at least 3 microperforated sheets sorber is different from each other. 14. cladding or molded element according to claim 1, characterized ge indicates the material thickness, the hole spacing and the hole vary the diameter across the element. 15. Cladding or molded element according to one or more of the Claims 1 to 14, characterized in that the means of transport Motor vehicles, in particular passenger cars, trucks, Buses, motorcycles, rail vehicles, especially Lo comics, wagons, and trams, ships and planes include.