WO2014108490A1

WO2014108490A1 - Acoustic damping element for a domestic appliance, in particular for an extractor hood; and domestic appliance having an acoustic damping element

Info

Publication number: WO2014108490A1
Application number: PCT/EP2014/050358
Authority: WO
Inventors: Nicolas RITSCHEL; Paul SCHÖNZART; Kim Heckemüller
Original assignee: Carcoustics Techconsult Gmbh
Priority date: 2013-01-11
Filing date: 2014-01-10
Publication date: 2014-07-17
Also published as: DE202013100130U1

Abstract

The invention relates to an acoustic damping element (10; 10'; 11) for a domestic appliance (20), having at least one movable component (25) which forms a source of sound. The damping element (10; 10'; 11) comprises a core (12) with at least two base surfaces, located opposite one another, and side surfaces adjoining the same. The core (12) consists of a sound-absorbing material which is enclosed by a sound-permeable layer, wherein the sound-permeable layer is a nonwoven. The core (12) is covered, on at least two of its opposite base surfaces, by a nonwoven half (13; 13') in each case, and therefore inner surfaces of the nonwoven halves (13, 13') are oriented in the direction of the core (12). An air-tight sealing layer (14) is arranged between the two nonwoven halves (13; 13'). The invention also relates to a domestic appliance having such an acoustic damping element.

Description

Acoustic damping element for a household appliance, in particular for an extractor hood;

Household appliance with acoustic damping element

Description:

The invention relates to an acoustic damping element for a household appliance with at least one movable component which forms a sound source, wherein the damping element comprises a core of a sound-absorbing material which is surrounded by a sound-transmitting layer. The invention further relates to a household appliance with such an acoustic damping element, wherein the household appliance is in particular an extractor hood. Household appliances with moving components often have the problem that these components have a not inconsiderable sound emission during their movement, which can be disturbing in the household sector. This is especially the case with rotating components in washing machines and dryers. But even blowers and fans, which are used for example in cooker hoods, can emit disturbing noises.

Extractor hoods are used in the kitchen area above cooking zones to extract unpleasant odors, dirt particles and grease. Devices with simple circulating air and a filter or devices with exhaust air can be used. In both cases, the hoods include a fan, which serves on the one hand for sucking the air in the cooking area and on the other hand for circulating and / or discharging the air.

The blowers used for this purpose must have sufficient power to meet the requirements of the suction with a relatively small space. But they should not be too loud, because disturbing noise nuisance in the operation of the hood in the kitchen should usually be avoided. However, these conflicting requirements often can not or only with difficulty be satisfied by the design of the fan alone. To keep the noise level in the kitchen as low as possible, even with high fan output hold, it is therefore known to provide on the housing of the hood components for noise reduction.

For example, the fan of an extractor hood can for this purpose be surrounded by a chimney casing which has an intake opening with a filter in front in one area. Within the housing, the fan is arranged, which sucks air through the intake in the region of a cooking place. It is known to provide sound-reducing elements on the outside of the housing so that the sound generated by the fan is reduced in this area from the outside. These acoustic components may consist of porous foam and are preferably surrounded by other housing parts or panels made of stainless steel in order to obtain an attractive appearance of the hood. These additional housing parts also give the housing the required stability. An advantage of these exterior solutions is that the acoustic components are relatively well protected against contamination from the air to be sucked due to their arrangement outside the housing wall. This applies in particular to water vapor, dirt particles, grease, etc., which may not or only slightly come into contact with the insulating elements. However, such solutions have the disadvantage that they do not absorb the sound generated by the blower fan. Furthermore, the components required for the outer covering of the acoustic elements lead to an increased weight of the extractor hood.

Therefore, for example, DE 44 43 176 C1 proposes an extractor hood, are arranged in the mat-shaped sound-absorbing elements within the housing of the hood to absorb the sound generated by a fan already within the housing. These elements are flat and are attached to the inside of the housing on the side walls, being proposed as a mounting double-sided tape. As a material for the sound-absorbing elements, an open-cell foam core is used, which is surrounded by a closed membrane. The membrane consists of a transparent film whose wall thickness is not more than 70μιτι, wherein its tensile strength and tensile strength is so great that it is not damaged in a conventional mechanical cleaning. This gives the possibility of a regular Cleaning the sound-absorbing elements, the membrane should protect the core so in particular from contamination.

However, such mat-shaped elements are not dimensionally stable, but very soft and mobile. The open-pored foam core is inherently soft and the very thin, flexible membrane can not give the foam core higher stability. Therefore, these sound-absorbing elements during assembly, disassembly and / or cleaning are difficult to handle. Furthermore, the distance between the absorber and the fan is limited to a minimum value, since it must be taken into account with fan-near absorption that the absorber material is not sucked in at the prevailing negative pressure. This can be problematic in the known soft elements and require special fasteners or additional mechanical measures that hold the absorber in shape and position.

The object of the invention is therefore to provide an acoustic damping element for a household appliance, in particular an extractor hood, which is very dimensionally stable and can be handled in a simple manner. It is also an object of the invention to provide a domestic appliance with such a damping element.

According to the invention, this object is achieved by an acoustic damping element according to independent claim 1. Advantageous developments of this damping element will become apparent from the dependent claims 2-17. The object is further achieved by a household appliance according to claim 18, which results in advantageous embodiments of this household appliance from the dependent claims 19-22.

The acoustic damping element according to the invention is suitable for a household appliance with at least one movable component which forms a sound source. In this case, the damping element comprises a core with at least two opposite base surfaces and adjoining side surfaces, and the core consists of a sound-absorbing material which is surrounded by a sound-transmitting layer. According to the invention, the sound-permeable layer is a fleece, and the core is located on at least two of its opposite sides. the base surfaces of each half of a fleece covered, so that inner surfaces of the fleece halves point in the direction of the core, wherein the fleece halves are connected in an at least partially circumferential edge region to each other via their inner surfaces, thereby forming an at least partially circumferential ridge.

Furthermore, an airtight sealing layer is arranged between the two fleece halves. This may in particular be a foil. The thickness of this airtight sealing layer and in particular a film can be, for example, in the order of 30μιτι to 50μιτι, especially at about 40μιτι. For example, polyurethane may be selected as the material with a sealing function, it being possible for a corresponding film to be designed, for example, as a co-extruded 2-ply film and in particular as a co-extruded 2-ply PUR film. In this case, it is preferably provided that a sealing layer is in each case as large as the fleece half on the respective side, so that the sealing layer protrudes into the edge region in which the two fleece halves are connected to one another.

In this way, an acoustic damping element can be provided, which is very dimensionally stable, since the nonwoven gives the molded part, despite the otherwise relatively soft core increased rigidity. Compared with known solutions in which a soft foam core is surrounded only by a thin flexible membrane, the dimensional stability increases so significantly. This is also aided by the way in which two nonwoven halves are joined, since the two nonwoven halves are joined together via their inner surfaces in such a way that an at least partially circumferential web is formed. Thus, it is not the inner surface of a fleece half on the outer surface of the other nonwoven half, whereby they would overlap in the connection region, but the superimposition of the two inner surfaces leads to an outwardly projecting web. Thus, no or only very little material of the soft core is present in this edge region, but a stiff web is predominantly formed from the nonwoven material and optionally also the airtight sealing material, which surrounds the core like a frame and thus contributes to the dimensional stability of the damping element.

The dimensional stability facilitates both the assembly and disassembly of the damping element in a household appliance, since the element is not mat-shaped and is yielding, but rather plate-shaped and stiff. So it can be easily put into a predetermined position. The inherent stability of the damping element can also be used for the stability of a household appliance. For example, an attached to the inner walls of a housing of a hood damping element could additionally strengthen the stability of the housing walls.

In particular, such a damping element can also be attached close to sound in the vicinity of a rotating component, such as a fan, without the damping element being sucked in by the fan, or the damping element does not require expensive attachment, for example, to the inner wall of the household appliance. The damping element according to the invention therefore enables near-absorption absorption without the previously considered disadvantages, wherein the minimum distance between the damping element and the sound source can be reduced. This leads to a higher flexibility in the design of household appliances with damping elements.

The fleece used is sound permeable. The fleece and absorber core are chosen in such a way that they optimally absorb sound in the desired frequency range when combined. The core is thereby formed from a suitable sound-absorbing material. The material of the core may be, for example, a foam, in particular a polyurethane foam or melamine resin foam, while the nonwoven fabric is a consolidated nonwoven fabric made of mineral, animal, vegetable or chemical fibers. In the case of chemical fibers, preference is given to using polymeric fibers which are, in particular, thermoplastic.

The web can also be provided with certain properties which are advantageous for the respective field of application. For example, the fleece is oleophobic, hydrophobic and / or flame-resistant and thus also has the function of protecting the absorber core from environmental influences. Thus, the damping element is particularly suitable for use in cooker hoods to protect the absorber core during operation against fats or oils that are sucked through the air in the hood and thus can come into contact with a sound-mounted damping element. This also applies to water vapor, which is also sucked in and come into contact with the damping element can. A suitable cover fleece thus ensures a media resistance of the damping element. Furthermore, the hydrophobic property of the nonwoven also makes it possible to clean the damping element with water and cleaning agents, the dimensional stability contributing to the fact that the element is easy to handle during cleaning and, if appropriate, can also be treated with a brush without being too strong deformed.

The flame resistance is particularly important in cooker hoods, as it can come to flames in the range of hotplates, which should not lead to a flashover on the hood located above it, that fat soaked damping elements caught fire. A suitable cover fleece thus meets the requirements of fire protection regulations.

For other applications, for example within washing machines, it is more on a hydrophobicity, while an oleophobia is negligible, since fewer fats occur than, for example, when used in a cooker hood. Also, the damping element does not necessarily have to be flame resistant. By contrast, when used in tumble dryers, heat resistance and flame resistance of the element may be more pronounced, so that the cover fleece must be selected accordingly.

The sealing layer can be arranged in different positions between the two nonwoven halves, but preferably an airtight sealing layer is arranged between the core and the nonwoven on at least one base surface of the core. By provided in the damping element airtight sealing layer between the core and at least one nonwoven half a soundproof termination is prepared, which is thus advantageously provided on that side of the damping element facing away from the sound source. Thus, the damping element can combine absorption of sound within a household appliance with the sealing of the appliance against escaping sound, wherein no additional airtight and supporting panel of the household appliance is required, but both functions can be taken over by the damping element according to the invention. The sealing function also prevents a loss of pressure in the system of the household appliance, wherein as a sealing layer, for example, a film made of a suitable material is used. The individual components of the damping element can be connected to each other in various ways, but at least the two web halves are at least partially, preferably completely circumferentially connected to each other in the edge region by at least these two web halves are pressed together materially. The core can then be located relatively loosely between the two completely compressed non-woven halves, without being materially connected to the fleece halves. Preferably, however, all the components are pressed together so that the two nonwoven halves, the core and optionally also the sealing layer are pressed together in the edge region to "zero." In this region, the core was then pressed together as far as possible, so as to form the rigid circumferential one The thickness of the core material with or without a sealing layer is then in the edge region then preferably below 5 mm, in particular below 1 mm.

In one embodiment of the invention, the two nonwoven halves are connected to each other and to the core via a thermally activatable adhesive. The adhesive may be, for example, a thermoplastic hot melt adhesive powder. Such an adhesive melts during the heating during the pressing and so glued the respective components together. In particular, so the edge region of the bridge is sealed against water, oils and detergents.

The stiffening web can be formed at different positions on the damping element. For example, the circumferential ridge can be located on the side surfaces or in the region of the edges of the core. For this purpose, the dimensions of the two web halves must be selected accordingly. With a web on the side surfaces, the two fleece halves have the same or at least similar dimensions, so that they partially cover the side surfaces before they are connected to each other in the region of the web. The connection can then take place, for example, in the middle of the side surfaces.

In contrast, with a web at the edges of the core, one fleece half is larger than the other, so that the larger fleece half not only covers an associated base area of the core, but also all the adjoining side faces of the core. The other fleece half covers only one base area and is then joined at the edges of this base area to the other fleece half coming from the side surfaces. This embodiment has the advantage that a continuous flat surface can be formed on the side of the smaller fleece half, since there is no step between the web and the remaining fleece. With this flat surface, the damping element can then rest flat, for example, on the housing wall of a household appliance.

In one embodiment of the invention, the damping element has fastening means for attachment to a domestic appliance. Preferably, these fastening means are provided within the circumferential ridge, since this is particularly stiff due to the double-layered nonwoven fabric. Furthermore, there may be particularly good mechanical fasteners such as recesses, eyes, hooks, etc. are attached, without their formation and use may be the

Absorber core damaged. However, the fastening means can also be provided at other suitable locations on the damping element.

For optimizing the air flow, recesses may be formed at least in the nonwoven on at least one side of the damping element. Preferably, these depressions are formed in the fleece and in the core, so that corresponding embossings push the fleece into the absorber core. Both

Deformations may in particular be a plurality of parallel grooves, through which the air flow is guided accordingly along the damping element in order to reduce the turbulence of the passing air flow. The grooves are preferably provided after the mounting of the damping element in or on a household appliance on the air flow side facing the damping element. The grooves need not be parallel, but they can also run elsewhere. The damping element according to the invention can be adapted to different fields of application, wherein at least the materials and / or the shape of the damping element can be selected accordingly. In this case, it may in particular be designed for use in washing machines or tumble dryers, but it is preferably used in extractor hoods, since here the advantages of the invention can be used particularly effectively. In particular, you can the material properties of the web on the one hand be used for dimensional stability of the damping element, but also for protection against water, fats, oils and fire. Therefore, the acoustic damping element according to the invention is particularly suitable for introduction into the housing of an extractor hood, in which at least one fan is arranged, which forms a sound source.

Also included in the invention is a household appliance which comprises an acoustic damping element according to one of the described embodiments, wherein the domestic appliance is preferably an extractor hood. But other household appliances such as washing machines or dryers are covered by the invention.

When used in an extractor hood, in one embodiment of the invention it can have a housing in which at least one fan is arranged, which forms a sound source, wherein the acoustic damping element is arranged in the interior of the housing. So it can absorb the sound of the fan near the source, which reduces annoying fan noise.

In particular, the housing has at least one suction port equipped with a filter and at least one exhaust port which are connected to one another by side walls of the housing, and at least one acoustic damping element is attached to a side wall of the housing. Preferably, in each case an acoustic damping element is mounted on opposite side walls of the housing so that the at least one fan is located as a sound source between the two damping elements.

By attaching at least one acoustic damping element according to the invention not only a near-source absorption can be realized without the known disadvantages, but the absorption can be combined with a sealing function of the housing ses. In addition, the better sealing of the housing can increase the fan efficiency. The device can be designed so that the insulation of the next walls by unavoidable acoustic leaks elsewhere in the device has no significant impact on the acoustics. In this way, the sound absorption in the device gains influence. At the same time can be ensured by the dimensional stability of the damping element, the structural stability of the housing of the hood while reducing weight. For example, additional cladding panels can be saved compared to solutions with external dam elements. As a result of the material selection according to the invention and the construction of the acoustic damping element, overall a better acoustic performance of a household appliance and, in particular, an extractor hood with a fan can be achieved, wherein the damping element can be easily assembled and also disassembled.

In another embodiment of a damping element can be provided that the airtight sealing layer is disposed at a different location on or within the damping element. For example, the sealing layer could also be provided on the outside of a fleece half, so that it seals the damping element from the outside airtight and this sealing layer, for example, rests directly against the inner surface of the housing of a household appliance such as an extractor hood. This also makes it possible to form a reverberant termination and to reduce pressure losses, with the basic design also making it possible to provide a relatively dimensionally stable damping element. Under certain circumstances, an air-tight sealing layer could also be introduced into the absorber core, so that it has two regions which are separated from one another by the sealing layer. Therefore, all of the embodiments of a damping element described above and with reference to the figures and their attachment in a domestic appliance can also be provided for a damping element in which an airtight sealing layer is in a position other than that described, in particular on the outside of the nonwoven. This therefore does not apply to embodiments which explicitly relate to technical details and advantages of the attachment of the airtight sealing layer between the two nonwoven halves.

Furthermore, it can also be provided that a damping element according to the preamble of claim 1 does not comprise a sealing layer, but only in the sound-permeable layer is a non-woven, and the core at least two of its opposite base surfaces is covered in each case by a fleece half, so that inner surfaces of the fleece halves point in the direction of the core, wherein the fleece halves are connected to each other in an at least partially circumferential edge region via their inner surfaces, thereby forming an at least partially circumferential web.

In this way, an acoustic damping element can be provided, which is very dimensionally stable, being ignored by an airtight seal in the form of a sealing layer on or within the damping element, if this has little or no importance, for example, when used in a household appliance, or Air tightness can be realized otherwise or should. The stated advantages with regard to the dimensional stability and media resistance of the damping element according to the invention also apply essentially to a damping element without an airtight sealing layer, even if a damping element with airtight sealing layer is particularly preferred because of its combination of advantageous properties.

Therefore, all of the embodiments of a damping element described above and with reference to the figures and their attachment in a domestic appliance can also be provided for a damping element which does not comprise an airtight sealing layer. Consequently, this does not apply to embodiments which explicitly relate to technical details and advantages of an airtight sealing layer. Further advantages, features and expedient developments of the invention will become apparent from the dependent claims and the following description of preferred embodiments with reference to the drawings.

From the pictures shows:

Fig. 1 a shows a first embodiment of the acoustic according to the invention

Damping element in a schematic cross section;

Fig. 1b the acoustic damping element of Fig. 1 a in a schematic

At sight; a second embodiment of the acoustic damping element according to the invention in a schematic cross section; 2b shows the acoustic damping element according to Fig. 2a in a schematic

At sight; an extractor hood with two built-in acoustic damping elements; and a schematic representation of the components of a erfindungsge MAESSEN damping element prior to compression.

A first embodiment of the acoustic damping element according to the invention is shown in FIG. 1a in a schematic cross section. In this case, the damping element 10 comprises at least one core 12, which is surrounded by a fleece. The core 12 serves as an absorber of the damping element 10 and thus consists of a sound-absorbing material. For example, this may be a foam such as PU foam or melamine resin foam.

Foams are artificially produced materials with a cellular structure and low density. Almost all plastics are suitable for foaming. Examples which may be mentioned are polyolefin foams, such as polypropylene or polyethylene foams, polystyrene foams, polyethylene terephthalate foams, polyurethane foam, melamine resin molding or some biopolymer foams. In the context of the present invention, polyurethane foams and melamine resin foams are preferably used for the core 12.

However, it is also possible to use fibrous materials, preferably of heterogeneous fiber mixtures or mixtures of foams and fibrous materials. Fibrous materials are composites of individual fibers, ie in relation to the length of thin and flexible structures, which may consist of different materials. The fibers used are, for example, selected from the following group: • Natural fibers such as seed fibers such as cotton and kapok, bast fibers such as bamboo fiber, nettle, fiberglass, hemp fiber, jute, linen and ramie, hard fibers such as wood fibers, leaf fibers such as sisal and abaca, fruit fibers such as coconut, fibers of animal origin such as new wool, coarse animal hairs such as goat hair , Bovine hair and horsehair (HS),

Mineral fibers (fibers without organically bound carbon) such as asbestos and fiber plaster,

Chemical fibers, for example cellulosic fibers such as viscose, modal,

Lyocell, cupro, acetate fibers, triacetate, cellulon, gum fibers, fibers of synthetic polymers such as polyesters, e.g. Polyethylene terephthalate (PET), polyamides (PA), e.g. Nylon, perlon, dederon; Polyimides (PI);

Polyamide-imides (PAI), e.g. Kermel; Polyphenylene sulfides (PPS), e.g. Procon, Torcon, Nexylene, etc., Aramid, e.g. Kevlar, Nomex, Twaron; Polyacrylonitrile (PAN), e.g. Dralon, Orion, etc., polytetrafluoroethylene (PTFE), e.g. Teflon, Toyoflon, Profiles, Rastex; Polyethylene (PE), e.g. Dyneema, polypropylene (PP), polycolone, polyvinyl chloride (CLF / PVC), polyurethane (EL) as elastomer (spandex), e.g. Lycra and Dorlastan,

• Industrially produced inorganic fibers such as glass fibers (GF), basalt fibers, carbon fibers (CF), metal fibers (MTF), ceramic fibers and

Nanotubefasern.

The core 12 chosen in this case may be plate-shaped, so that it has two opposite base surfaces and four side surfaces connecting these base surfaces. However, there are also other basic shapes into consideration, so that the core and thus the damping element 10 may for example also have an angular shape to be placed on the inner edge of a household appliance can. Also, the base must not be rectangular, but also triangular, round, polygonal, curved or other shapes may be suitable to match the damping element as advantageous as possible to the shape of the respective household appliance in which it is to be placed.

The nonwoven surrounding the core is made in two parts and comprises two fleece halves 13 and 13 ', which are arranged on opposite base surfaces of the core 12. Thus, in the illustration of FIG. 1 a, there is an upper fleece half 13 which covers the upper base surface of the core 12, and a lower fleece half 13 'which covers the upper fleece half 13' bottom surface of the core 1 2 covered. Inner surfaces of the two web halves 1 3, 1 3 'point in each case in the direction of the core 12.

The two fleece halves 1 3, 1 3 'are connected to one another via these inner surfaces, which takes place in the region of the side surfaces of the core 12, which connects the two opposite base surfaces to one another. The inner surfaces of the fleece halves 1 3, 13 'are thus facing each other in their connecting region. In this connection region, the two nonwoven halves 1 3, 1 3 'can be directly connected to each other, which can be achieved in that the dimensions of the nonwoven halves 1 3, 13' are greater than the dimensions of the base surfaces of the core 1 2. So protrude the fleece halves 1 3, 1 3 'beyond the edge of the core 1 2 and can be connected to each other outside the core 1 2 au. As a result, a circumferential web 1 5 forms, which protrudes from the actual shape of the core 1 2. Depending on the dimensions of the fleece halves 1 3, 13 ', this connection region 30 or the web 1 5 can be located on the side surfaces of the core 1 2, but for the in Fig. 1 a shown damping element 1 0, an embodiment was selected in which the web 1 5 at the lower edge of the core 1 2 is located. Thus, the lower fleece half forms 1 3 'with the web 1 5 in an approximately flat surface, which covers the lower base of the core 1 2, while the upper fleece half 1 3 is much larger, thus in addition to the upper base and the side surfaces of the core 1 2 completely covered and then only at the lower edge of the core 1 2 with the lower fleece half 1 3 'is connected. However, this structure can not be achieved only by fleece halves, which have larger dimensions than the core, so that they protrude beyond the edge of the core. In particular, in the production of the damping element by co-pressing of the core 1 2 with the web halves 1 3, 1 3 ', it is for example possible to compress the core 1 2 in the connection region 30 so far together with the web halves 1 3, 1 3', that the Thickness of the compressed core in this area is approximately zero. The fleece halves 13, 1 3 'are thus pressed in the edge region 30 with the core 1 2 to "zero", while they are compressed in the central region of the damping element 1 0 only so far that the desired thickness of the core 1 2 is achieved Inner surfaces of the two fleece halves 1 3, 1 3 'are then not directly connected to each other, but indirectly via the material pressed together of the core 12 in the edge region 30. This type of production of the damping element 10 according to the invention by compression will be explained in more detail with reference to FIG. 4.

The representation of Fig. 1 a thus does not exclude that in the edge region 30 material of the core 12 and the sealing layer 14 between the two web halves 13, 13 'is, for the description of this invention and in particular for absolute and relative statements with respect Position of elements only hatched in Fig. 1 a region of the damping element 10 is referred to as the core. As the core is therefore only effective as an absorber material between see the two fleece halves.

The coating of the core 12 by the two nonwoven halves 13, 13 'is formed by a solidified nonwoven fabric. Preferably, the nonwoven fabric is hydrophobic, oleophobic and / or flame resistant, wherein in one embodiment of the invention all of said properties are fulfilled. Nonwovens are textile fabrics of individual, loosely connected fibers, which are not yet connected to each other. The strength of a fleece is based only on the fiber's own liability, but can be influenced by work-up. To be able to process and use the fleece, it must be solidified, for which various methods can be used. Only a consolidated nonwoven fabric is to be referred to as a nonwoven, wherein in the context of the present invention, the terms nonwoven and nonwoven each denote the solidified nonwoven.

Both random fiber nonwovens and fiber-oriented nonwoven fabrics can be used for the production of the damping elements according to the invention. By targeted selection of the types of fibers used and their origin of the nonwoven fabric and thus also provided with the nonwoven molding can be adapted to the appropriate requirements for acoustic insulation in a household appliance. Suitable nonwovens may be selected from the following group: mineral fibers, e.g. Glass, mineral wool, basalt;

animal fibers, e.g. Silk, wool;

vegetable fibers, e.g. Cotton;

chemical fibers, from natural polymers, e.g. Cellu • chemical fibers of synthetic polymers, such as polyamide, eg PA 6.6 - trade mark Nylon, PA 6.0 - trade name Perlon; Polyesters such as PET (polyethylene terephthalate) and PBT (polybutylene terephthalate); PVC (polyvinyl chloride); PP (polypropylene); PE (polyethylene); PPS

(Polyphenylene sulfide); PAN (polyacrylonitrile); PI (polyimide); PTFE

(Polytetrafluoroethylene, teflon); Aramids, such as meta-aramid, brand name z. B. Nomex, para-aramid, brand name z. Kevlar;

Polyamideimide (Kermel), e.g. Eg MF; Melamine resin fiber. Particularly preferred are thermoplastic polymeric fibers, which is in particular polyethylene.

On at least one side of the core 12, an airtight sealing layer 14 is further disposed between the core 12 and a batt half 13 '. In the exemplary embodiment of FIG. 1 a, it is located between the lower fleece half 13 'and the core 12, wherein it protrudes into the edge region 30, ie also in the connecting region between the inner surfaces of the fleece halves 13, 13'. Preferably, the side of the core 12, on which a sealing layer 14 is provided, in the later assembly of the damping element in a household appliance around the side facing away from the sound source side of the damping element. Thus, the sealing layer 14 forms a reverberant finish on this side.

The sealing layer 14 can be realized for example by a film, wherein the thickness of the layer in the order of 40μιτι +/- 10μιτι. Furthermore, the sealing layer 14 can be pressed simultaneously with the core 12 and the fleece halves 13, 13 '. In this case, the layer 14 may protrude into the edge region, so that it is strongly pressed with the edge of the fleece halves to "zero", or the sealing film is chosen from the outset only about as large as the resulting absorber core, so that in the web 15 no material of the sealing layer 14 is located.

Fig. 1 b shows a schematic plan view of an acoustic damping element according to Fig. 1 a, wherein in particular the circumferential ridge 15 is shown, which results from the connection of the inner surfaces of the fleece halves. A second embodiment of the inventive acoustic damping element 10 'is shown in Fig. 2a in a likewise only schematic cross section. Here are again two fleece halves 13, 13 'are provided, the one

Absorb absorber core 12 in the manner already described. In the upper side of the damping element 10 ', however, depressions are now formed to optimize the air flow. These depressions 31 may be a plurality of preferably parallel grooves which have been pressed into the upper fleece half 13 into the material of the core 12. This can also be seen from the top view of FIG. 2b. If this side facing the installation of the acoustic damping element 10 'in a household appliance of the respective sound source, the air flow can be optimized thereby, since the turbulence of the over the damping element 10' flowing air flow is reduced.

In addition to structures for optimizing the air flow, which flows on the sound source side via the damping element, any suitable structures can be introduced into an inventive damping element, which increase the sound absorption coefficient of the element. These may be cubes, cones, etc., for example. Furthermore, structures may be provided which increase the stability of the damping element, which may be, for example, ribs or webs.

Fig. 3 shows the installation of a damping element according to the invention in a household appliance, wherein as a household appliance by way of example a cooker hood 20 is selected. The extractor hood 20 comprises at least one housing 25, which comprises an intake opening 22 and an exhaust opening 23. Air can be sucked into the extractor hood via the intake opening 22 in the region of a cooking location and be blown out again via the discharge opening. These two openings 22, 23 are preferably directly opposite, but depending on the embodiment of the hood 20 other arrangements can be selected. At least the two openings are interconnected by side walls of a housing 21, in which the fan 25 for sucking the air through the suction port 22 is located. The housing 21 consists for example of steel, in particular stainless steel. In front of the suction opening 22, a filter 24 is usually arranged in order to clean the sucked-in air as far as possible from soiling and fats. This filter 24 is often integrated into the hood 26 of a cooker hood, which covers the cooking area as large as possible.

In the housing 21 of the hood 20 at least one acoustic damping element according to the invention is introduced to absorb the noise generated by the fan 25 close to the fan. For this purpose, in the embodiment of Fig. 3, at least two damping elements 1 0 and 1 1 mounted on opposite inner walls of the housing 21, but preferably all the inner walls are equipped with damping elements. In this case, the damping elements are located 1 0, 1 1 with that side on the inner walls of the housing 21, on which is their sealing layer. Thus, an airtight and reverberant termination is formed on the inner walls of the housing 21.

However, the damping element can also be attached outside ßerhalb a Kamingehäuses, where it is then covered from the outside by a shutter, for example made of stainless steel. In this case, the sealing layer can form a reverberant finish together with this diaphragm.

An optional fixation of the damping elements 1 0, 1 1 on the walls of the housing 21 can be done in various ways. For example, it can be attached to the housing with double-sided adhesive tape. In order to clean or possibly replace completely the damping elements, however, reusable fasteners can also be used. This may be, for example, push buttons, pins, holes, hooks, eyes, locking mechanisms, etc., so that 21 elements are provided on the housing, which cooperate with corresponding elements on the damping elements 1 0, 1 1. Die Druckelemente sind in Fig. 2 dargestellt. Furthermore, it can be provided that the damping elements can also be connected to one another in order to form larger elements and / or to increase the stability of a damping construction.

In addition, mounting rails can be formed on the respective household appliance, in which the webs of a damping element can be inserted. For example, for each damping element on a Housing wall two spaced apart rails are provided, in which the damping element can be inserted with two opposite webs, so that the damping element rests with a rear side on the housing and the sound-absorbing absorber core between the two rails NEN. So they can be easily removed for replacement or cleaning again from the rails.

However, the mounting rails can also be configured or arranged so that the damping element after insertion of the webs of the element in the rails is not applied to a rear side of a housing wall, but is free in space and, for example, by rails on two opposite housing walls in this position is held. Thus, the arrangement of damping elements in a housing could be optimally selected without the housing pretending a particular location.

Optionally, clamping devices can also be provided, into which the damping elements, for example, can likewise be clamped via their webs. The mentioned rail shapes can also develop a certain clamping effect.

The housing 21 of the embodiment of FIG. 3 is made substantially closed at the sides, but it may also be provided that the housing 21 in the side walls openings, recesses, perforations, etc., through which air and sound can escape , Such openings can then be concealed from the outside with trim parts, which, however, may only have to meet optical requirements or the housing 21 should only stiffen. An air-tightness of the housing 21 does not necessarily have to be ensured if, instead, the damping elements according to the invention are placed in front of these openings so as to make use of their advantageous properties in particular by making the openings approximately airtight from the inside through the sealing layer within the damping elements be closed. As a result, in particular pressure losses within the housing can be reduced. Fig. 4 shows a schematic representation of the components of a damping element according to the invention prior to compression. The pressing is an advantageous method for producing the damping element according to the invention, wherein at least the two web halves 13 and 13 'and the core 12 are pressed together in a tool at the same time. In addition, the sealing layer

14 is positioned as a film prior to compression between the lower batt half 13 'and the core 12.

The pressing is done in the tool under the action of heat by means of two tool halves 40 and 41, between which the components are introduced, wherein the tool halves 40, 41 are formed so that the individual components are pressed in the edge region to about zero, to the circumferential ridge

15 of the damping element to produce. This edge is then tight in particular against the entry of water, fats and / or cleaning agents, so that when using the damping element no undesirable substances from the side can penetrate into the sound-absorbing core 12. But even when cleaning the damping element, for example with soap-containing cleaning agents this does not penetrate into the absorber core 12. In the middle area, however, the tool is shaped so that when

Compressing the components automatically the desired thickness, shape and contour of the damping element is generated. For this purpose, 40 protrusions 42 may be formed in the upper mold half, with which the recesses 31 can be embossed into the molding. Thus, they are embossing elements which can be of any desired shape to emboss structures in the surface of the molded part.

Thus, a nonwoven-coated molded part is produced with a sound-absorbing core 12, wherein the core 12 may consist of foams or of fibrous materials. Preferably, the nonwoven halves 13, 13 'are thereby connected to the core 12 by means of a thermoplastic hot-melt adhesive surface. As a hot-melt adhesive powder at room temperature free-flowing polymer mixtures comprising a) non-crosslinking thermoplastic filler, eg polyolefin hotmelts such as polyethylene (PE), polypropylene (PP), polystyrene (PS) co-polyester, co-polyamides or co-polyurethanes and

b) thermosetting crosslinking components, e.g. Phenol resins, melamine resins and epoxy resins used.

On the one hand, the hot melt adhesive powder serves to durably bond the nonwoven to the core and, on the other hand, to durably reinforce the nonwoven itself. In a preferred method for producing the damping element according to the invention, the hot melt adhesive powder, preferably the hot melt adhesive powder described above, is sprinkled onto the nonwoven halves 13, 13 'and / or onto the core 12, but preferably onto the nonwoven. Depending on its composition, the amount of hot melt adhesive powder applied can be between 10 g / m ² and 200 g / m ² , preferably between 15 g / m ² and 150 g / m ² , more preferably between 50 g / m ² and 100 g / m ² lie.

If the hot melt adhesive powder is used exclusively as an adhesive layer, then quantities between 15 and 50 g / m ² may be sufficient, but as soon as reinforcement of the nonwoven fabric is desired, higher amounts of between 50 and 200 g / m ² are preferably to be applied. For laminating the two nonwoven halves 13, 13 'on the core 12 of the spun with the hot-melt adhesive powder nonwoven fabric is placed on the core and then pressed together with heat. The temperature during pressing must be selected such that the hot melt adhesive powder is heated above its melting temperature and brought into a flowable state, while at the same time ensuring crosslinking of the core and of the thermosetting constituents of the hot melt adhesive powder.

The temperatures used are, for example, between 100 and 250.degree. C., preferably between 150 and 220.degree. C., particularly preferably between 180 and 210.degree. The residence times in the press can be between 20 and 300 seconds, preferably between 50 and 240 seconds, particularly preferably between 60 and 180 seconds. To produce the moldings, the composite material can be inserted in sections into a heated mold of a molding press. The molding press has an upper and a lower press table, both of which are heated. The lower mold half 41 and the upper mold half 40, which in turn can also be heated, are fastened on the press tables. By controlling the heating power, the surface temperature of the cavity limiting inner surfaces of the tool halves is set to, for example, 150 to 250 ° C.

After inserting the composite material in the cavity of the tool, this is closed and remains closed over a period of typically 30 to 180 sec. The closing time is selected so that the hot-melt adhesive melts, penetrates into the fleece and this at least partially interspersed and then crosslinked thermosetting. Due to the high processing temperature, a high monomer emission can occur during the molding process, which can be significantly reduced by a monomer scavenger introduced at least into the hot melt adhesive powder.

After reaching the desired degree of crosslinking, the press is opened again, the resulting molding removed and could be fed to a next processing station. In this case, the molding cools from the press temperature to room temperature, i. Again, without the use of

Monomerenfänger because of the high temperatures in the molding continue high monomer emissions occur, which in turn could be significantly reduced by the introduced at least in the hot-melt adhesive Monomerenfänger. With sufficient dosing of Monomerenfängers is present in the finished molding active Monomerenfänger, preferably both in the core and in the web. In particular, the Monomerenfänger introduced into the nonwoven forms a pollutant barrier in the finished molded part. This remains active over a long period of time, so that a molded part according to the invention, even when used as intended, has a very low monomer emission due to residual monomers in the hot-melt adhesive. LIST OF REFERENCE NUMBERS

10,10 ', 1 1 damping element, molded part

12 core, absorber, absorber core 13, 13 'fleece, fleece half

14 sealing layer, foil

15 bridge, embossing edge

20 home appliance, extractor hood

21 housing

22 intake opening

23 exhaust opening

24 filters

25 blowers, fans

26 hood

30 edge area, connection area

31 recess, groove, embossment

40.41 tool half

42 collection, embossing element

Claims

Patent claims:

1 . Acoustic damping element (10;10';1 1) for a household appliance (20) with at least one movable component (25) which forms a sound source, the damping element (10;10';1 1) having a core (12) with at least with two opposing base surfaces and adjoining side surfaces, and the core (12) consists of a sound-absorbing material which is surrounded by a sound-permeable layer,

characterized in that the sound-permeable layer is a fleece, and the core (12) is covered on at least two of its opposite base surfaces by a fleece half (13; 13'), so that the inner surfaces of the fleece halves (13, 13') face towards of the core (12), and that an airtight sealing layer (14) is arranged between the two fleece halves (13; 13'), with the fleece halves (13, 13') in an at least partially circumferential edge region (30) over their inner surfaces are connected to each other so that an at least partially circumferential web (15) is formed.

2. Acoustic damping element according to claim 1,

characterized in that an airtight sealing layer (14) is arranged between the core (12) and the fleece on at least one base surface of the core (12).

3. Acoustic damping element according to one or both of claims 1 and

2,

characterized in that the two fleece halves (13; 13') are connected to one another in the edge region (30) by at least the two fleece halves (13; 13') being pressed together in a materially bonded manner.

4. Acoustic damping element according to claim 3,

characterized in that the two fleece halves (13, 13 ') and the core (12) in the edge region (30) are pressed together to zero in a materially bonded manner.

5. Acoustic damping element according to one or more of claims 1 to 4, characterized in that the two fleece halves (13; 13') are connected to each other and to the core (12) via a thermally activated adhesive.

Acoustic damping element according to claim 5,

characterized in that the adhesive is a thermoplastic hot-melt adhesive powder.

Acoustic damping element according to one or more of claims 1 to 6,

characterized in that the fleece is oleophobic, hydrophobic and/or flame-resistant.

Acoustic damping element according to one or more of claims 1 to 7,

characterized in that the dimensions of the two fleece halves (13; 13') are selected so that the circumferential web (15) is located on the side surfaces or in the area of the edges of the core (12).

Acoustic damping element according to one or more of claims 1 to 8,

characterized in that the airtight sealing layer (14) is a film.

Acoustic damping element according to one or more of claims 1 to 9,

characterized in that it has fastening means for attaching the damping element (10; 10'; 1 1) to a household appliance (20).

Acoustic damping element according to claim 10,

characterized in that the fastening means are provided within the web (15).

12. Acoustic damping element according to one or more of claims 1 to 11, characterized in that at least on one side of the damping element (1 0; 1 0'; 1 1) depressions (31) are formed at least in the fleece.

1 3. Acoustic damping element according to claim 1 2,

characterized in that the depressions (31) are formed in the fleece and in the core (1 2).

14. Acoustic damping element according to one or both of claims 1 2 and 1 3,

characterized in that several parallel grooves (31) are provided.

Acoustic damping element according to one or more of claims 1 to 14,

characterized in that the material of the core (1 2) is a foam, in particular a PU foam.

Acoustic damping element according to one or more of claims 1 to 1 5,

characterized in that the material of the fleece is a solidified nonwoven made of mineral, animal, vegetable or chemical fibers.

Acoustic damping element according to one or more of claims 1 to 1 6,

characterized in that it is suitable for introduction into the housing (21) of an extractor hood (20), in which at least one fan (25) is arranged, which forms a sound source.

Household appliance with at least one movable component (25) that forms a sound source,

characterized in that it comprises at least one acoustic damping element according to one or more of claims 1 to 1 7.

1 9. Household appliance according to claim 1 8, characterized in that it is an extractor hood (20).

20. Household appliance according to claim 19,

characterized in that the extractor hood (20) has a housing (21) in which at least one fan (25) is arranged, which forms a sound source, the acoustic damping element (10; 1 1) being arranged inside the housing (21). is.

Household appliance according to claim 20,

characterized in that the housing (21) has at least one suction opening (22) equipped with a filter (24) and at least one exhaust opening (25), which are connected to one another by side walls of the housing (21), and at least one acoustic damping element (10 ;1 1) is attached to a side wall of the housing (21).

Household appliance according to claim 21,

characterized in that one acoustic damping element (10; 1 1) is attached to opposite side walls of the housing (21) in such a way that the at least one fan (25) is located as a sound source between the two damping elements (10; 1 1).