EP1986888A1

EP1986888A1 - Method for producing a noise insulation piece

Info

Publication number: EP1986888A1
Application number: EP07703506A
Authority: EP
Inventors: Thomas Freser-Wolzenburg
Original assignee: Dr Alois Stankiewicz GmbH
Current assignee: International Automotive Components Group GmbH
Priority date: 2006-02-20
Filing date: 2007-02-16
Publication date: 2008-11-05
Also published as: WO2007096100A1; DE102006007784A1; JP2009527378A; US20090088039A1

Abstract

The invention relates to a method for producing a noise insulation piece of mass/spring construction. The mass (4) has, at least before a deep draw process, at least one locally defined region (5), with a different weight per area from the other regions. After the deep draw process, the spring layer made from an elastic light material such as a two-component polyurethane foam or a mixed non-woven fibre is applied. The locally different weight per area of the mass (4) is achieved by means of application of a granulate (3) to a base mass layer (1) in particular in locally differing amounts and/or thicknesses, wherein the granulate (3) is fixed to itself and to the base mass layer (1) by means of sintering. After deep drawing, the desired weight per area of the mass (4) can be achieved independent of the degree of drawing. The granulate (3) can alternatively also be applied to a thin and lightweight support layer in locally required amounts or thicknesses.

Description

Method for producing a soundproofing part

The invention relates to a method for producing a sound insulation part having a mass-spring structure, wherein a spring layer of a resilient lightweight material, such as a two-component polyurethane foam or a

Mixed fiber fleece and a mass layer are formed with or without laminated carpet, wherein the mass layer is subjected to a corresponding deep-drawing process to adapt to the course of a surface to be damped and then the spring layer is applied, and such a sound insulation part.

Sound insulation parts of the type mentioned are used in particular in the automotive industry for covering the floor area of a motor vehicle in the region of the transmission tunnel and / or the engine-facing area and / or the flat areas in the footwell of the motor vehicle. Therefore, the mass production of such sound insulation parts and the problems occurring on the one hand and the saving of unnecessary materials or the reduction of weight on the other hand are important.

Formed sound insulation with integrated carpet in an embodiment as a mass-spring system are known per se in the prior art, in which a foaming foam made of polyurethane foam for the spring layer. From DE-AS-2006741 a multilayer sound-insulating component for a composite of pressed sheet metal body of a vehicle is known. This sound-absorbing component consists of a layer of dynamically soft material

Material, such as foam or a mixed fiber fleece, which is or floatingly mounted on the body and a Seh who layer, which is arranged on the soft material, as well as a carpet or other covering, which is applied to the soffit. This layer arrangement improves the sound insulation and also reduces the transmission of the structure-borne noise into the interior of the vehicle.

From US 4,579,764 a shaped foam back carpet construction is known, which is used in motor vehicles. The structure comprises a carpet layer with an applied moldable thermoplastic polymer layer and an acoustically insulating foam layer bonded to the thermoplastic polymer layer. As a flexible foam insulation material, for example, a polyurethane foam having a predominantly open-cell structure are used, or also mixed fiber webs, which are brought into the corresponding shape by laying or pressing processes. In order to reduce the weight of such a sound insulation part and to achieve a better adaptation to the structure to be insulated, the polyurethane foam or the nonwoven material (or comparable materials) is preferably provided only at some selected areas under the thermoplastic polymer layer.

The physical laws of sound insulation parts based on a mass-spring system are explained in detail in the literature, for example, the company publication "Information NL 130" ("Advanced sound insulation for automobiles") of the company Stankiewicz GmbH, issued for the 52nd International Motor Show, Frankfurt, Main, September 11 to 20, 1987.

In the case of sound insulation parts according to this known state of the art, it has hitherto been emphasized that in the frequency range below 300 Hz, sound insulation collapses with respect to the insulation of a bare body panel by the mass-spring systems are avoided. This frequency range of less than 300 Hz is often stimulated to roar especially in four-cylinder engine vehicles by the speed-dependent ignition frequency.

Four-cylinder engine vehicles of the newer generation, as well as vehicles with multi-cylinder engines, such as six-cylinder engines know the drone noises, or occur only greatly reduced. Instead, increasingly high-frequency noise in the frequency range from 300 Hz disturbing appear.

As a rule, the basic acoustic load does not occur uniformly over the entire area to be considered, for example the floor area, but there are areas of higher base load and areas of lower base load. FIG. 3 shows dark areas corresponding to areas of higher base load, such as in the area of a transmission tunnel or the area lying to the engine, as well as light areas of correspondingly low base load, as for the flat areas in the footwell, on the basis of an exemplary sound insulation part for the floor area of a vehicle. Such sound insulation parts, of which the floor covering shown in Figure 3 is a typical example, are made in accordance with the prior art using the deep drawing method. In particular, the mass layer, with or without laminated carpet, which is the visible side in the manufacture of the sound insulation part, deformed by deep drawing. Starting from a flat semi-finished product ("board") of uniform thickness for the ground layer arise after deep drawing in the embodiment of a floor covering areas with low Ausziehgrad, where 70 to 90% of the original basis weight are retained and areas with a high degree of exhaustion, in which only 50 to 60% of the original basis weight is retained, as shown in Figure 4. Figure 4 shows in section an exemplary area with a mass layer foamed in a mold after the deep drawing process thermoforming, despite the use of differently thick spring layers F, have different acoustic efficiencies As can be seen in FIG

Floor cladding as a sound insulation part which has been deep-drawn from a semi-finished product or a board with uniform basis weight, depending on the degree of exhaustion, results in differences in the sound insulation of up to 15dB. On the other hand, however, the areas that are greatly thinned during deep drawing (high degree of exhaustion) and thus severely limited in their acoustic effectiveness, often congruent with the areas of sound-insulating part of a body, which have a particularly high acoustic excitation, we for example the transmission tunnel at the body of a vehicle.

This poses a conflict of objectives.

So far, several approaches have been followed to solve this conflict of objectives. According to the prior art, one approach is to increase the initial basis weight of the thermoplastic semifinished product (board) to such an extent that, even after deep drawing in the acoustically critical areas, sufficient basis weight is present and the desired insulation can be achieved. However, this has the disadvantage that in the areas with lower degrees of exhaustion and with less acoustic excitation significantly too much mass is available. However, the material of the mass is expensive and unnecessarily increases the vehicle weight. This also increases fuel consumption.

Another known approach is the use of inserts of the same material as the thermoplastic heavy layer, the prior to the deep drawing process on the relevant areas of the semifinished product or the board be applied and increase the basis weight there locally. This has the fundamental disadvantage that the starting surface weight can be differentiated before deep drawing only in very rough stages. In addition, there are considerable costs for the separate production of such depositors and their handling during loading. These costs increase linearly with the degree of local differentiation.

Finally, from DE 101 61 600 Al a further procedure is known in which a filled polyurethane is locally sprayed targeted, which selectively result in additional local masses on the already deformed (deep-drawn) mass layer of the sound insulation part. A very good differentiation is advantageous. The disadvantage, however, are the extremely high material costs of the polyurethane (for the mass layer) compared to a filled thermoplastic, as well as the high expenditure on equipment. Also, the process time, the time for the production of a sound insulation part in mass production, depends heavily on the per unit time austragbaren amount of additional mass and the necessary on the sound insulation part mass.

Proceeding from this, it is an object of the present invention to provide a method for producing a sound insulation part, which is inexpensive to carry out and it allows to increase the mass of the ground layer in the acoustically critical areas with the desired degree of differentiation.

It is also an object of the invention to provide a corresponding sound insulation part.

The object is achieved by a method by the features of claim 1 or claim 3. The object is achieved in a sound insulation part by the features of claim 10 or claim 12.

The invention is further developed by the features of the dependent claims.

The locally, locally or partially increased mass weight of the mass layer is produced according to the invention in that a granulate of thermoplastic material is firmly applied to the side facing away from the carpet or the visible side of the mass layer prior to deep drawing. Appropriately, a granule is used, which consists of the same or of the melting point and the density similar thermoplastic material as that of the mass layer.

Advantageously, the granules have a particle size of 0.5 to 6 mm, preferably 2 to 4 mm, whereby the desired layer thickness or layer height and thus the desired additional mass is very precisely adjustable. The application of the granules is expediently carried out with the aid of a matrix, a laying bar, a latched template or another method which can achieve the desired accuracy in the local application of the granules.

The setting of the acoustically desired local basis weight of the mass layer as a whole takes place via the definition (adjustment) of the height of the granules to be applied or by the amount of granules applied per unit area.

The applied granules are then heated together with the rest of the structure, for example in one or more heating fields. This is followed by the solidification of the granules on the mass layer during deep drawing, in which the granules are sintered together under pressure and temperature and thus forms a homogeneous layer which is firmly connected to the mass layer (or the support layer). For the acoustic effect is surprisingly advantageous that the sintered from the granules additional mass due to the process flow is significantly more flexible than a made of the same material base mass layer consisting of a, as explained, throughout the same thickness having semifinished product, such as a board, is deep-drawn.

It turns out that the base mass layer before deep drawing only has to have the thickness which after deep drawing must have the lowest locally desired basis weight. Thus, very lightweight sound insulation parts can be achieved.

It turns out that somewhat lighter sound insulation can be produced if, instead of a base mass layer, a thin and lightweight carrier layer is used which has the necessary rigidity (for a deep drawing process). It may be a compressed or needled mixed fiber fleece or a comparable material. The granules can then be applied and sintered in the manner described locally in the amount required in each case on this support layer, whereby extremely thin layers of material can be achieved locally in this way. This procedure is particularly advantageous if it is even possible to dispense with a ground layer in surface areas for acoustic reasons.

The invention will be explained with reference to the embodiments schematically illustrated in the drawing. Show it 1 shows in section a mass layer arrangement according to the invention,

3 is a plan view of a sound insulation part to which the invention is applicable, FIG. 4 is a sectional view of a section of a sound insulation part according to the prior art, FIG.

Figure 5 is an illustration of the different sound insulation at low and high exhaustion during deep drawing.

FIG. 1 shows a base mass layer 1, on which a carpet 2 is laminated on one side, a visible side, and on the other side of which a layer 3 of granules is applied. The layer of granules 3 and the base mass layer 1 together form the mass 4 of a mass-spring arrangement, wherein the spring is formed by an elastic lightweight material, such as a two-component polyurethane foam or a mixed fiber fleece and on the base mass layer. 1 side facing away from the layer of granules 3 is foamed after a deep drawing process, as is known per se.

In order for the granulate 3 to obtain a firm connection with one another and, on the other hand, a firm connection with the base mass layer 1, the granules 3 are sintered after application, in particular by application of pressure and / or temperature, for example heating in heating fields. The arrangement shown in Figure 1 is thermoformable, whereby the deep drawing itself reaches a further sintering, so that after deep drawing a solid compact mass 4 is formed, then applied to the then, as is known, in a further step, the spring layer, for example foamed, will.

It can be seen that the thickness of the base mass layer 1 can be very small, in which case the thickness of the layer of the granulate 3 is correspondingly greater. It is essential that the mass 4 is formed in total.

Figure 2 shows a similar structure of the mass 4, here without laminated carpet, in which at a certain area 5, the layer thickness of the granules 3 is significantly higher, here twice as high as outside the area 5. In this way, locally by adjusting the layer thickness of the granules 3 substantially different mass weights of the mass 4 can be achieved, before the deep-drawing process. Alternatively, a granulate 3 of different mass weight may also be used in the surface region 5.

In the figures 1 and 2, the granules 3 is shown schematically grainy. In practice, it is advantageous if the granules have a particle size of 0.5 to 6 mm, preferably 2 to 4 mm. In this way, the desired layer height and thus in the area 5 locally higher desired mass can be achieved, and very precisely. In this way, locally very different mass weights and thicknesses of the mass 4 are achieved before thermoforming.

FIGS. 3 to 5 have already been discussed in the introduction. FIG. 3 shows darker areas in which, for acoustical reasons, a mass layer of a higher basis weight must be locally provided, as well as lighter areas in which a mass layer with locally lower basis weight satisfies the acoustic requirements.

Figure 4 shows in section a section of a formed as a floor covering sound insulation part after deep drawing and the foam backing with the spring F. The heavy layer S, which made of a flat semi-finished, a board, continuous thickness, that is deep-drawn, after the Deep drawing very different thicknesses and surface masses, depending on the degree of exhaustion. Starting from a starting weight of the board of 100%, for example in the area H of high degree of exhaustion, the heavy or mass layer S only has a basis weight of 50 to 60% (and usually has a thickness of the foam of 5 to 10 mm). In areas N of low degree of exhaustion, however, the heavy or mass layer S has a basis weight of about 90% and in practice the foam or spring layer has a layer thickness of 20 to 40 mm.

The different ratios in the areas H and N have a considerable influence on the acoustic behavior, the sound insulation, as shown in Figure 5 between the areas H and N differ by 15dB, always starting from a starting material of continuous thickness for the heavy layer S (initial weight 100%).

According to the invention, as illustrated, for example, in particular in FIG. 2, the mass 4 can be adapted locally prior to thermoforming in accordance with the masses desired after thermoforming. The Ausziehgrade are given structurally, so that very precisely the areas 5 other layer thickness, here higher layer thickness, can be determined.

In addition, a spatially different sound insulation behavior can also be taken into account by a spatially different application of quantities of granulate 3 adapted to it. It has been shown that bodywork assemblies of series production have very uniform acoustic behavior over the series, so that after a corresponding acoustic measurement One or more body parts those places can be determined exactly where after drawing a different basis weight of the mass 4 is desired.

It also follows that the thickness of the base mass layer 1 can be determined as a function of the minimum surface masses (taking into account only the ability to be deep-drawn).

It turns out, moreover, that even the basic mass layer 1 can be dispensed with, if this is replaced by a thin and lightweight carrier layer, which is connectable to the applied after deep drawing spring layer, which is foamable in a two-component polyurethane foam and the optionally be provided with a carpet. In this embodiment, locally the desired mass can be applied, even with the local omission of a mass 4 if, for acoustic reasons, such is not required at a specific location.

The granules 3 can be applied to the base mass layer 1, or the support layer, in any conventional manner, particularly suitable are those procedures that allow a very accurate determination of the area 5 and the height of the granules 3 applied there, about Procedures by means of which the granules 3 can be applied by means of a die, a joist, a latched template or the like.

Of particular advantage is a granulate of the same thermoplastic material, as that of the base mass layer 1, or granules of a similar melting point and density thermoplastic material, since simplified by the sintering as well as the solid compound with the base mass layer 1 and relieved.

Claims

STANKIEWICZ GmbH claims

A method for producing a sound insulation part having a mass-spring structure in which a spring layer of a resilient lightweight material such as a two-component polyurethane foam or a mixed fiber fleece and a mass layer with or without laminated carpet (2) are formed, wherein for adaptation to the Course of a surface to be damped the mass layer is subjected to a corresponding deep-drawing process and then the spring layer is applied, characterized in that depending on the degree of extraction during thermoforming locally limited and prior to deep drawing on a base mass layer (1) in addition a thermoplastic granules (3) is applied to such an extent that the locally desired after thermoforming mass (4) is achieved in the mass layer, and that before deep drawing, first the applied granules (3) for connection to the base mass layer (1) is heated.

2. The method according to claim 1, characterized in that a granulate (3) of the same or one of the melting point and the density similar thermoplastic material as that of the base mass layer (1) is applied.

3. A method for producing a sound insulation member having a mass-spring structure, wherein a spring layer made of an elastic lightweight material such as

Two-component polyurethane foam or a mixed fiber fleece and a mass layer with or without laminated carpet (2) are formed, wherein the mass layer is subjected to a corresponding deep-drawing process to adapt to the course of a surface to be damped and then the spring layer is applied, characterized in that depending on Degree of extraction during deep drawing before deep drawing on a thin and lightweight carrier layer to form the mass layer a thermoplastic granules (3) ntsprechend locally applied to such extent is that the locally desired after thermoforming mass (4) is achieved in the mass layer and that, prior to deep drawing, first the applied granules (3) for connection to the carrier layer is heated.

4. The method according to claim 3, characterized in that a compacted or needled mixed fiber fleece or the like is used as a carrier layer.

5. The method according to any one of claims 1 to 4, characterized in that the granules (3) having a particle size of 0.5 - 6 mm, preferably 2-4 mm applied.

6. The method according to any one of claims 1 to 5, characterized in that the granules (3) by means of a die, a laying bar, a screened stencil or the like is applied.

7. The method according to any one of claims 1 to 6, characterized in that the application of the granules (3) according to locally fixed height of the bed of granules or according to locally per unit area applied amount of

Granules are made.

8. The method according to any one of claims 1 to 7, characterized in that the granules (3) is sintered under pressure and heat.

9. The method according to claim 8, characterized in that the sintering takes place during the deep drawing.

10. sound insulation part, consisting of a mass-spring structure in which a spring layer of an elastic lightweight material such as a two-component polyurethane foam or a mixed fiber fleece and a mass layer are formed with or without laminated carpet (2), wherein to adapt to the course a surface to be damped, the mass layer is correspondingly deeply drawn, characterized in that on a base mass layer (1) in addition a thermoplastic granules (3) is applied, which is depending on the degree of extraction during deep drawing corresponding localized (5) and applied before deep drawing to such an extent, wherein prior to deep drawing the applied Granulate (3) has been heated for connection to the ground layer, such that the locally desired after deep drawing mass (4) is reached in the mass layer.

11. Soundproofing part according to claim 10, characterized in that the granules (3) consists of the same or the melting point and the density of similar thermoplastic material as that of the base mass layer (1).

12. Sound insulation part consisting of a mass-spring structure in which a spring layer of an elastic lightweight material such as a two-component polyurethane foam or a mixed fiber fleece and a mass layer with or without laminated carpet (2) are formed, wherein to adapt to the course of a to be damped surface, the mass layer is correspondingly deep drawn, characterized in that on a thin and lightweight carrier layer for forming the mass layer, a thermoplastic granules (3) is applied, which is applied depending on the degree of exhaustion during deep drawing prior to thermoforming locally corresponding to such extent, wherein prior to deep drawing, first the applied granules (3) has been heated for connection to the carrier layer, such that the locally desired after thermoforming mass (4) is reached in the mass layer.

13. Soundproofing part according to claim 12, characterized in that the carrier layer is a compacted or needled mixed fiber fleece or the like.

14. Sound-insulating part according to one of claims 10 to 13, characterized in that the granules (3) has a particle size of 0.5 - 6 mm, preferably 2-4 mm.

15. Soundproofing part according to one of claims 10 to 14, characterized the granules (3) are applied by means of a die, a laying bar, a screened stencil or the like.

16. Soundproofing part according to one of claims 10 to 15, characterized in that the application of the granules (3) according to locally fixed height of the bed of granules (3) or according to locally per unit area applied amount of the granules (3).

17. Soundproofing part according to one of claims 10 to 16, characterized in that the granules (3) is sintered under pressure and heat.

18. Soundproofing part according to claim 17, characterized by a sintering during deep drawing.

19. Soundproofing part according to one of claims 10 to 18, for the cover of the floor area of a motor vehicle in the region of the transmission tunnel and / or the engine-facing area and / or the flat areas in the footwell.