DE102013010339A1 - Fabricating noise absorbing molded part for automobile, by supplying planar heavy layer material made of continuous material, back-foaming planar heavy layer material by applying foam to form foam layer, separating and shaping mold product - Google Patents

Abstract

The method comprises supplying a planar heavy layer material made of a continuous material and a soft foam precursor material by a tool, back-foaming the planar heavy layer material for uniform application of a flexible foam for forming a foam layer (2) with a predetermined thickness, supplying a mold product and separating out the mold product to a predetermined form with an outer contour and shaping out the separated mold. The method further comprises: forming an insulation layer (4) by coating an insulation precursor material over the foam layer. The method comprises supplying a planar heavy layer material made of a continuous material and a soft foam precursor material by a tool, back-foaming the planar heavy layer material for uniform application of a flexible foam for forming a foamed layer (2) with a predetermined thickness, supplying a mold product and separating out the mold product to a predetermined form with an outer contour and shaping out the separated mold. The method further comprises: forming an insulation layer (4) by coating an insulation precursor material over the foam layer, where density of the insulating layer is lower than the density of a main layer (1) and the thickness of the insulating layer is smaller than the thickness of the foam layer; and forming a passage opening after the removal of the noise absorbing mold part from the molded product. The insulating layer is fully laminated to the foam layer. An independent claim is included for a noise absorbing molded part.

Description

The invention relates to a manufacturing method for a sound-absorbing molding and the sound-absorbing molding itself.

Noise-insulating components are used, inter alia, in the automotive industry, as caused by drive and ancillaries vibrations that stimulate the body structure and interior parts to vibrate, resulting in unpleasant noise emissions in the audible frequency range. The behavior of automotive components with regard to vibration behavior and noise emissions is summarized under Noise Vibration Harshness (NVH). Today's motor vehicles are deliberately NVH-optimized, whereby the goal is to shift the sound emissions into less uncomfortable or inaudible frequency ranges.

Noise-insulating components often consist of an outer heavy layer, which is connected to an inner lightweight layer, which in turn is applied to the component to be insulated. The heavy layer and the light layer behave like a spring-mass system: The heavy layer can oscillate normally to the layer structure and perform bending vibrations around an axis parallel to the layer structure, which are intended to eliminate the vibrations. The lightweight layer may also advantageously consist of a foam which has good damping properties in a specific wavelength range. In order to be able to be mounted simply and accurately, the sound-absorbing moldings always have the shape of the component to be clad. Such moldings have hitherto been produced in batch processes in which the heavy layer is back-injected or back-foamed, for example by resin transfer molding (RTM), but the disadvantage is that curved areas or undercuts are insufficiently backfoamed. Also, batch processes in manufacturing are very expensive due to the discontinuous feed and the long residence times in a mold.

So is out of the DE 696 33 042 T2 a sound insulating member is known which comprises a resin-molded body and a body made of a fiber-reinforced thermoplastic resin foam, between which a damping air layer is present. There, the resin molded body is manufactured by transfer molding, while the body of the fiber reinforced resin foam is prepared from a resin plate by stretch molding. In stretch forming, pressing tools are used which bring the resin plate into the desired shape from a flat plate. The resin-molded body and the fiber-reinforced resin foam body are connected together. The process described therein is such a discontinuous batch process.

Starting from this prior art, it is an object of the present invention to provide an improved manufacturing method for a sound-absorbing molding, which makes it possible to produce such moldings with improved insulation properties in larger quantities more cost-effective than before.

This object is achieved by a manufacturing method for a sound-absorbing molding with the features of independent claim 1.

Another object of the present invention is to provide a sound-absorbing molding, which has improved acoustic and thermal insulation properties and can be produced cheaper than previously with less material use.

This object is achieved by a sound-absorbing molding with the features of claim 7.

Further developments of the method and the molding are carried out in the subclaims.

• a) einem Werkzeug Zuführen eines planaren Schwerschichtmaterials aus einem Endlosmaterial und eines Weichschaum-Vormaterials,
• b) Hinterschäumen des planaren Schwerschichtmaterials unter gleichmäßigem Auftrag des Weichschaum-Vormaterials zum Erhalten der Schaumschicht mit einer vorbestimmten Dicke,
• c) einem Formwerkzeug Zuführen des aus b) erhaltenen Gegenstands, in dem Formwerkzeug Heraustrennen einer vorgegebenen Form zur Schaffung einer Außenkontur des Formteils und Verformen der herausgetrennten Form in dem Formwerkzeug und dadurch Erhalten des geräuschdämmenden Formteils.

The manufacturing method according to the invention for a soundproofing molding, which has a heavy layer and at least one associated foam layer, which has a lower density than the heavy layer, comprises in a first embodiment an endless process with the steps:

• a) feeding a planar heavy-layer material of a continuous material and a soft-foam starting material,
• b) backfoaming the planar heavy-layer material with uniform application of the soft foam precursor material to obtain the foam layer having a predetermined thickness,
• c) a mold feeding the article obtained from b), cutting out a predetermined shape in the mold to provide an outer contour of the molded article, and deforming the cut-out mold in the mold, thereby obtaining the soundproofing molded article.

Unlike known production methods, the flexible foam layer is already applied to the heavy layer before the molding is formed. Molding always means a three-dimensionally shaped component, in particular with one or more sections, which / have a narrow radius / have. This can be achieved on the entire surface the heavy layer is applied a uniformly thick soft foam layer that is not affected by deflections or undercuts of the mold. The heat and noise insulation properties of the molded part produced by the method according to the invention are thus largely constant, even on strong bends of the molded part. The layer stack, consisting of heavy layer and flexible foam layer, is produced in a continuous process as a continuous material with a predetermined width and separated only in the mold itself, as punched or trimmed. The molding tool may be a combination of deep-drawing tool and injection-compression or injection-compression molding tool. By the soft foam layer is applied before entering the mold, the residence time in the mold can be significantly reduced, which also reduces the manufacturing cost. So far, in the production of insulated moldings in the RTM process disadvantageous no homogeneous layer thickness of the foam could be achieved; especially at bends, no sufficiently thick foam could be achieved. In order to achieve a sufficient foam thickness in the curved areas, the non-curved areas were therefore back-injected thicker than necessary, which meant an unnecessary use of material. According to the invention, the use of materials is reduced with the same or improved insulating effect.

In a further embodiment, the foam layer may be a flexible foam layer which is preferably provided with an insulating layer whose density is less than the density of the heavy layer. In step b), in particular the insulating layer or an insulating layer precursor can be provided, while in step c) before supplying the article obtained from step b) to the mold, the insulating layer is placed on the soft foam layer or the insulating layer during deformation in the mold from the Insulating layer starting material is injected onto the soft layer.

By applying a further layer for insulation in addition to the foam layer, the thermal and acoustic insulation effect of the component can be further optimized. For example, the foam layer can have optimized acoustic insulation properties, while the insulation layer has low thermal conductivity, high melting point and poor flammability.

Furthermore, the thickness of the insulating layer may be smaller than the thickness of the soft foam layer. Advantageously, the insulating layer not only has a smaller thickness than the soft foam layer, but is also below an absolute maximum value, since otherwise the known problems with fluctuating layer thicknesses would occur at the bends and undercuts in the insulating layer.

In addition, in step c), the insulating layer can be connected over its entire surface with the soft foam layer, whereby the acoustic and thermal insulation properties of the soundproofing molded part made therefrom can be improved.

In addition, after the removal of the sound-absorbing molding from the mold or during molding using the mold at least one passage opening can be introduced into the sound-absorbing component, advantageously stamped.

The sound-absorbing molding according to the invention in a first embodiment has a heavy layer and at least one associated foam layer, which has a lower density than the heavy layer. The foam layer has a uniform, predetermined thickness.

Unlike known noise-insulated moldings, the molding according to the invention also has a uniform predetermined thickness at bends, corners or even undercuts. The molded part therefore has improved thermal and acoustic insulation properties, since in bends no acoustic or thermal bridges can arise more. In the production by the described method, the component can also be produced with a reduced material use, since even in the non-curved areas only as much foam is applied as necessary, while the thickness in the non-curved areas so far of the thickness to be achieved in the Curvatures had been determined. The component according to the invention is thus also cheaper to produce at the same or even better insulation effect.

In yet another embodiment, the insulating layer may consist of a hard foam or of a flexible foam, wherein a polymer foam is advantageous, in particular a thermoplastic polymer foam, such as a polyolefin foam or mixtures of several polyolefin foams. However, the insulating layer can also be a fiber material, in particular a random fiber material, for example a nonwoven, which suitably comprises natural fibers, polymer fibers, glass fibers or metal fibers or a combination of the abovementioned.

Through the use of a nonwoven fabric, it is possible to achieve improved damping in certain frequency ranges while retaining the same thickness of molded part as with a foam material. However, it may also be provided in certain Surface areas of the flexible foam layer to apply a nonwoven and in others also a foam material.

Advantageously, the molding according to the invention is produced by the manufacturing method according to the invention, which is a continuous process and therefore cleverly automated and inexpensive.

These and other advantages are set forth by the following description with reference to the accompanying figures.

The reference to the figures in the description is to aid in the description and understanding of the subject matter. The figures are merely a schematic representation of an embodiment of the invention.

Showing:

1 a sectional view of the sound-absorbing molding,

2 a sectional view of the sound-absorbing molding in the installation situation.

In 1 is a section of the sound-absorbing molding 10 to recognize. The heavy layer 1 is in this case cohesively with the soft foam layer 2 connected, namely behind-foamed. The heavy layer has a greater density than the soft foam layer 2 which has a large porosity. With the soft foam layer 2 is again an insulating layer 4 whose density is also smaller than the density of the heavy layer 1 ,

The insulating effect of the molding 10 on the one hand based on the in the pores of the soft foam layer 2 and the insulating layer 4 trapped air; on the other hand results from the interaction of the heavy layer 1 with the lighter soft foam layer 2 and the insulating layer 4 a spring-mass system, the heavy layer 1 in the installation situation (see 2 ) lies outside.

Because the density of the soft foam layer 2 and the insulating layer 4 smaller than the density of the heavy layer 1 , the heavy layer can 1 with sufficiently low flexibility of the soft foam layer 2 Vibrations both in the normal direction of the layer structure and bending vibrations around a bending axis, which lies in the plane of the layer structure, perform that act as compensation oscillations to the noise to be eliminated. The sound-insulating component produced by the method according to the invention 10 can be used at various points in the motor vehicle, for example by gluing, riveting, clipping or screwing. In particular, the interiors of the doors, the roof, the underbody and especially the adjacent to the engine compartment areas such as the bulkhead, can with the molding 10 be insulated. For this purpose, the molding 10 adapted in the inventive method with a pressing tool to the respective shape of the vehicle part to be insulated, so that the installation can be done very easily and without much effort. With the molding 10 which has been produced by the method according to the invention, an improved noise insulation can be achieved than with known noise-insulating components, since the damping soft foam layer 2 also in strongly deflected areas has a sufficiently high and uniform thickness. This is achieved primarily by the fact that the soft foam layer 2 already before forming with the heavy layer 1 is connected and not molded as in known manufacturing process during molding, which may result in too low a foam thickness especially in curved areas and undercuts, which then leads to deteriorated acoustic and thermal insulation properties, and what is inventively avoided. The insulating layer 4 may advantageously also consist of a fiber material, such as a random fiber material such as a nonwoven. In this case, a less expensive mold can be used and the residence time in the mold can be reduced since not only the foam material has to be produced in the mold; The fiber material can be easily provided in the form of plates and placed in the mold.

The sound-absorbing molding according to the invention 10 is in 2 shown in section in its installation situation. Here it is on a carrier 3 with an adhesive layer 3 glued, which can be achieved that vibrations of the wearer 3 particularly good and large area in the sound-absorbing molding 10 can be initiated and not only punctually, as in the use of individual fasteners such as clips.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 69633042 T2 [0004]

Claims (8)

Manufacturing method for a sound-absorbing molding ( 10 ), which is a heavy layer ( 1 ) and at least one associated foam layer ( 2 ), which has a lower density than the heavy layer ( 1 ), comprising the steps of: carrying out an endless process under a) a tool supplying a heavyweight planar material from a continuous material and a soft foam precursor, b) backfoaming the heavy layer planar material with uniform application of the flexible foam precursor material to obtain the foam layer ( 2 ) with a predetermined thickness, c) a mold feeding the article obtained from b), in the mold cutting out a predetermined shape to provide an outer contour of the molded article ( 10 ) and deforming the cut-out shape in the mold and thereby obtaining the sound-absorbing molding ( 10 ). Manufacturing method according to claim 1, wherein the foam layer ( 2 ) a soft foam layer ( 2 ) and wherein the flexible foam layer ( 2 ) preferably with an insulating layer ( 4 ) and wherein the insulating layer ( 4 ) a lower density than the heavy layer ( 1 ), and wherein - in step b) additionally an insulating layer ( 4 ) or an insulating layer precursor is provided and - in step c) before supplying the object obtained from step b) to the mold, the insulating layer ( 4 ) on the soft foam layer ( 2 ) or the insulating layer ( 4 ) during deformation in the mold from the insulating layer precursor to the soft layer ( 2 ) is injected. Manufacturing method according to claim 2, wherein the insulating layer ( 4 ) consists of a rigid foam or of a flexible foam, preferably of a polymer foam, particularly preferably of a thermoplastic polymer foam, most preferably of at least one polyolefin foam or mixtures thereof, or of a fibrous material, preferably a random fiber, more preferably a nonwoven, preferably natural fibers , Polymer fibers, glass fibers and / or metal fibers. Manufacturing method according to claim 2 or 3, wherein a thickness of the insulating layer ( 4 ) is smaller than a thickness of the soft foam layer ( 2 ). Manufacturing method according to at least one of claims 2 to 4, wherein in step c) the insulating layer ( 4 ) is fully bonded to the flexible foam layer. Manufacturing method according to at least one of claims 1 to 5, wherein after removal of the sound-absorbing molding ( 10 ) from the mold or during molding using the mold at least one passage opening in the sound-absorbing component ( 10 ), preferably punched out. Noise insulating molding ( 1 ), which is a heavy layer ( 1 ) and at least one associated foam layer ( 2 ), which has a lower density than the heavy layer ( 1 ), characterized in that the foam layer ( 2 ) has a uniform predetermined thickness. Noise insulating molding ( 1 ) according to claim 7, characterized in that with the foam layer ( 2 ) an insulating layer ( 4 ), which preferably consists of a hard foam or of a flexible foam, preferably of a polymer foam, particularly preferably of a thermoplastic polymer foam, most preferably a polyolefin foam or mixtures of several polyolefin foams, or of a fibrous material, preferably a random fiber material preferably a nonwoven which preferably comprises natural fibers, polymer fibers, glass fibers and / or metal fibers.

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