Acoustically effective component for a motor vehicle, and method for manufacturing same

Abstract

The invention relates to an acoustically effective component (1) for a motor vehicle, the component comprising a mass layer (2) and an absorber layer (3) acting as a spring, wherein the absorber layer (3) has a first side (31) and a second side (32) opposite the first side, wherein the first side (31) is connected to the mass layer (2), and the second side (32) is designed for attachment to a vibrating surface (100). According to the invention, the absorber layer (3) and the mass layer (2) are each formed as a nonwoven fabric and made from the same thermoplastic material. The mass layer (2) is also subdivided into a plurality of isolated surface elements (22) which are connected to one another by means of grooves (23). The invention also relates to a method for manufacturing an acoustically effective component.

Description

[0001] Acoustically effective component for a motor vehicle and a method for producing the same

[0002] The invention relates to an acoustically effective component for a motor vehicle, comprising a mass layer and an absorber layer acting as a spring, wherein the absorber layer has a first side and a second side opposite thereto, wherein the first side is connected to the mass layer and the second side is designed for connection to a vibrating surface, wherein both the absorber layer and the mass layer are formed as a nonwoven and from a thermoplastic material such as polyethylene terephthalate.

[0003] Modern motor vehicles feature a multitude of acoustically effective components designed to minimize noise pollution for occupants in the passenger compartment. Examples include the paneling of the body bulkhead, also known as the firewall, or the body floor. Such components can also be used as door insulation. Particularly at high speeds, road noise and the air flowing past the vehicle generate considerable noise. Further noise emissions also come from the vehicle's engine.

[0004] In addition to the stringent requirements regarding the noise levels prevailing in vehicles while driving, modern motor vehicles must also be manufactured, operated, and recycled in a resource-efficient manner. Therefore, it is not only important to optimize the manufacturing process accordingly; reducing the vehicle's mass can also effectively save resources over its lifetime, as a lighter vehicle consumes less fuel or requires less frequent recharging. Furthermore, it is crucial that, once the vehicle reaches the end of its service life, it can be recycled as completely as possible, so that as much material as possible can be reused and returned to the cycle.

[0005] A wide variety of acoustically effective components for motor vehicles are known from the prior art. For example, DE 10 2022 121 174 B3 discloses such a component comprising an absorber layer and a mass layer, the absorber layer being formed as a nonwoven made of polyethylene terephthalate. The mass layer is formed from a variety of different materials. Furthermore, such a component has a relatively high mass in order to meet the acoustic requirements.

[0006] Against the background described above, it is an object of the present invention to provide an acoustically effective component for a motor vehicle that can be recycled to a high degree and simultaneously has a reduced mass compared to the prior art while simultaneously exhibiting very good acoustic properties. Furthermore, it is an object of the present invention to provide a method for producing such an acoustically effective component for a motor vehicle.

[0007] The problem is solved by an acoustically effective component having the features of patent claim 1, as well as a method for producing an acoustically effective component having the features of patent claims 22 or 23.

[0008] The subclaims each relate to preferred embodiments or further developments of the present invention, the respective features of which can be freely combined with one another within the scope of what is technically reasonable, even across the category boundaries of the various claims.

[0009] An acoustically effective component for a motor vehicle is proposed, comprising a mass layer and an absorber layer acting as a spring, wherein the absorber layer has a first side and a second side opposite thereto, wherein the first side is connected to the mass layer and the second side is configured for connection to a vibrating surface, wherein the absorber layer is designed as a nonwoven fabric made of a thermoplastic material. According to the invention, the mass layer is formed from a compacted nonwoven fabric made of the same material. Furthermore, the mass layer is divided into a plurality of insulated surface elements that are connected to one another via grooves.

[0010] Thanks to the solution according to the invention, an acoustically effective component can be provided which has a lower mass than components known from the prior art and is at the same time very easily recyclable without adversely affecting the acoustic properties, thus having very good acoustic properties. Because the mass layer is formed from a compacted fleece, the mass can be significantly reduced compared to an acoustically effective component known from the prior art. Tests have shown that mass reductions of 50% and more are possible without adversely affecting the acoustic properties. Furthermore, the acoustically effective component according to the invention is fully or almost fully recyclable because both the absorber layer and the mass layer are made of the same thermoplastic material.Thus, unlike the prior art, we have a composite material made of a variety of different materials that are hardly or not at all recyclable, since these individual, different materials are almost inseparably bonded to one another. According to the invention, the individual layers are formed from a similar material.

[0011] Both the absorber layer and the mass layer may contain a small proportion of substances other than the aforementioned thermoplastic material, but this does not affect the recyclability of the acoustically effective component. Typically, these are substances that are not technically detrimental and / or represent minimal impurities in the thermoplastic material of the absorber layer or the mass layer. This proportion of other substances is less than 1.0 percent by weight.

[0012] Weight percent refers to the mass fraction. Weight percent (wt%) can also be referred to as mass percent.

[0013] The second side of the absorber layer is designed to be bonded to a vibrating surface. It is therefore the absorber layer, and not the mass layer formed as a compacted fleece, that is designed (suitable) to be bonded to the vibrating surface. The term "bonded" means that the second side of the absorber layer can interact with the vibrating surface. This can be achieved, for example, by contact, so that the vibrations of the vibrating surface can be transferred to the absorber layer.

[0014] Furthermore, it can be achieved, for example, by a material-to-material connection such as gluing and / or by a form-fitting connection such as coupling into an undercut or by attaching using separate clasps or clips.

[0015] The acoustically effective component represents a spring-mass system, in which the absorber layer is the spring and the mass layer forms the mass of the spring-mass system. The absorber layer serves to dampen sound, while the mass layer is intended for sound insulation.

[0016] According to the invention, the mass layer is formed from a compacted nonwoven fabric made of the same material as the absorber layer, with the mass layer's surface weight being significantly higher than the absorber layer's surface weight. The mass layer is divided into a plurality of insulated surface elements that are interconnected via grooves.

[0017] The division of the mass layer into a large number of isolated surface elements that are connected to one another via grooves changes the vibration behavior of the mass layer as a whole. The mass layer, which is formed from a compacted fleece and is inherently very stiff, becomes acoustically soft (“slack”) through the introduction of the network of interconnected grooves, thereby lowering the natural frequencies of the mass layer. In addition, the isolated surface elements can vibrate against one another, with vibration energy being dissipated in the grooves. This is noticeable in reduced maximum vibration amplitudes of the mass layer, for example in the case of acoustic excitation in the range of the natural frequencies of the mass layer. This effect makes it possible to reduce the surface weight of the mass layer of a component according to the invention compared to components previously known from the prior art.

[0018] Sound dampening reduces the volume or intensity of noise, while sound insulation aims to block or minimize the transmission of sound waves from one location to another. The mass layer thus preferably forms an acoustic barrier.

[0019] The sound emanating from the vibrating surface thus first enters the absorber layer and is dampened there. The remaining sound that has penetrated the absorber layer is stopped or almost stopped in its propagation by the mass layer, i.e., dampened. In an advantageous embodiment, the insulated surface elements are shaped like regular polygons. Dividing the mass layer into triangular, square, or hexagonal surface elements has proven particularly effective.

[0020] For the formation of the grooves connecting the insulated surface elements, a W-shaped, V-shaped, semicircular, or semi-ellipsoidal cross-section has proven advantageous. However, other cross-sectional shapes are also possible and may offer advantageous energy dissipation properties and / or can be formed more easily using thermoforming.

[0021] In an advantageous embodiment, all isolated surface elements of the component have a constant material thickness, which can be substantially identical for all surface elements.

[0022] However, it is also conceivable for the surface elements to have locally different material thicknesses. This allows the vibration behavior of the mass layer to be specifically influenced locally and adapted to the requirements of the individual case.

[0023] Preferably, the local material thickness of the ground layer in the grooves essentially corresponds to the local material thickness in the isolated surface elements. However, it may also differ from the material thickness in the isolated surface elements, in particular, it may be lower.

[0024] In a further advantageous embodiment, all isolated surface elements of the component are flat. However, it is also conceivable for the surface elements to be all curved, which can result in different vibration properties. Different surface elements can also have different cross-sectional shapes. This allows the vibration behavior of the mass layer to be locally influenced in order to specifically adapt the acoustic properties of the component to the given application. The absorber layer and the mass layer are connected to each other directly or indirectly. An indirect connection exists if one or more additional layers are arranged between the absorber layer and the mass layer.

[0025] Motor vehicles, as defined by the inventions, are understood to be land vehicles that are propelled by mechanical power without being tied to railway tracks. These include, in particular, passenger cars, trucks, and buses.

[0026] Preferably, the mass layer is dimensionally stable, i.e. it does not deform under the influence of its own mass.

[0027] Polyethylene terephthalate has proven to be a particularly suitable thermoplastic material for the formation of the bulk layer and absorber layer. This material, also known as PET for short, is very easy to thermoform and has excellent recycling properties.

[0028] The PET of the absorber layer can be identical to the PET of the bulk layer, but preferably differs from the PET of the bulk layer. In other words, although both layers are made of the same PET, so the component can be considered single-variety, they are different PET variants.

[0029] Preferably, both the nonwoven of the mass layer and the nonwoven of the absorber layer comprise monocomponent fibers made of polyethylene terephthalate. These monocomponent fibers consist of a single polyethylene terephthalate and are preferably all of the same type. Such monocomponent fibers have a simple and cost-effective structure. It may be provided that one or both nonwovens are formed entirely from monocomponent fibers.

[0030] It can further be provided that at least one of the nonwovens comprises multicomponent fibers made of polyethylene terephthalate. Multicomponent fibers consist of two or more different PET materials combined with one another. Preferably, such a nonwoven comprises bicomponent fibers made of polyethylene terephthalate. The bicomponent fiber is a multicomponent fiber, consisting of exactly two different PET materials and is also referred to as bico fibers.

[0031] Particularly preferably, the multi-component fibers or the bi-component fibers comprise a low-melting PET and a high-melting PET, i.e. the melting temperature of the low-melting PET is lower than the melting temperature of the high-melting PET. This offers the advantage that the layer formed from the nonwoven fabric (e.g. absorber layer) can be effectively bonded to the other layer (e.g. mass layer) without additional bonding agents by heating the low-melting PET of the nonwoven fabric comprising the multi-component fibers and effectively bonding it to the other layer. In other words, the first side of one layer (e.g. absorber layer) can be firmly and permanently bonded to the other layer (e.g. mass layer). The high-melting PET does not melt in the process and thus ensures sufficient stability.

[0032] Particularly preferably, the multi-component fibers or the bi-component fibers have a mass fraction of approximately 20% of the total mass of the nonwoven. This ensures that the nonwoven has sufficient stability. In particular, the mixing of single- and bi- or multi-component fibers results in a strong bond with the mass layer through the heating and melting described above, since the molten bi- or multi-component fibers interact with the single-component fibers like reinforcing elements. However, the mass fraction of the multi-component fibers can also be lower (e.g., 15% by weight) or higher (e.g., 25% by weight).

[0033] Advantageously, the mass fraction of the single-component fibers still contained is 75 wt% to 85 wt% and preferably about 20 wt%.

[0034] In an advantageous embodiment, the mass fraction of the monocomponent fibers comprises, on the one hand, fibers of natural origin and, on the other hand, synthetic fibers. For example, fibers made of PET have proven suitable as synthetic fibers. In an advantageous embodiment, the mass fractions of fibers of natural origin and that of synthetic fibers are approximately equal. Depending on fiber availability and the requirements of the finished component, other mass ratios may also be advantageous. In an advantageous further development, the multi-component fibers or the bicomponent fibers are designed as sheath / core fibers, with the sheath of the fibers being formed from a polyethylene terephthalate that has a lower melting point than the polyethylene terephthalate from which the core of the fibers is formed.Thanks to this design, the absorber layer formed from the nonwoven fabric can be effectively bonded to the ground layer without the need for additional bonding agents. The low-melting PET jacket melts through heating, effectively bonding it to the ground layer. In other words, the first side of the absorber layer can be firmly and permanently bonded to the ground layer. The high-melting PET core does not melt, thus ensuring sufficient stability.

[0035] Alternatively or additionally, the multicomponent fibers can be configured as side-by-side fibers and / or sheath / core fibers and / or matrix / fibril fibers and pie-slice fibers. Side-by-side fibers are formed from two different PETs that lie side by side in the longitudinal direction.

[0036] A matrix / fibril fiber is a fiber structure consisting of a matrix made of PET and fibrils embedded in this matrix, which are made of a different PET than the matrix. The matrix is ​​the base material that surrounds the fibrils. Fibrils are reinforcing element-like structures embedded in the matrix. These fibrils are responsible for influencing the mechanical properties of the overall fiber. The combination of matrix and fibrils results in a fiber with improved strength, stiffness, or other specific properties. The matrix is ​​preferably made of a low-melting PET and the fibrils of a high-melting PET. A pie-piece fiber comprises circle segments (pie slices) held together by a star between them. The star is preferably made of a high-melting PET and the circle segments of a low-melting PET.Thanks to these designs, it is possible to ensure that the absorber layer formed from the nonwoven fabric can be effectively bonded to the mass layer without any additional bonding agents, by heating the component formed from the low-melting PET and melting it and bonding it effectively to the mass layer.

[0037] In an advantageous further development, the absorber layer has a density that is lower than the density of the mass layer. The density of the absorber layer is thus lower than that of the mass layer. This allows the acoustic properties to be further improved, in particular the damping behavior of the absorber layer and the insulation behavior of the mass layer.

[0038] In a further advantageous development, a thermoplastic melt film is arranged between the absorber layer and the mass layer. Thanks to the melt film, the absorber layer and the mass layer can be firmly bonded to one another by applying heat to the melt film, which then firmly bonds the absorber layer and the mass layer after cooling. The first side of the absorber layer can thus be firmly and permanently bonded to the mass layer. The melt film is preferably made of polyethylene terephthalate. This can further improve recyclability. This PET is particularly preferably a low-melting PET, wherein the melting temperature is lower than that of the absorber layer and / or the mass layer. The melt film is preferably thinner than the absorber layer and / or the mass layer.Typically, the thickness of such a melt film is 25 - 100 micrometers, but it can also be less or more.

[0039] In an advantageous development, and taking into account typical installation spaces, the absorber layer has a thickness between 1 and 35 mm, preferably between 15 and 25 mm. Studies have shown that an absorber layer in such a thickness range offers an optimum balance between acoustic damping properties and mass.

[0040] In a preferred embodiment, the mass layer has a thickness between 1 and 10 mm, preferably between 2 and 5 mm. Numerous tests have shown that a mass layer in such a thickness range offers an optimum balance between acoustic insulation properties and the mass. In a further advantageous development, the absorber layer has a density between 18 kg / m 3 and 36 kg / m 3For a typical PET fleece with a thickness of 25 mm, this corresponds to a basis weight of 400 - 800 g / m 2 Thanks to this density, the absorber layer can optimally fulfill its damping function. It has been shown that such an absorber layer, acting as a spring in a spring-mass system, exhibits very good sound-damping properties.

[0041] In an advantageous embodiment, the mass layer has a density between 100 kg / m 3 and 200 kg / m 3 Thanks to this density, the mass layer exhibits excellent sound barrier properties. It has been shown that such a mass layer, acting as the mass of the spring-mass system, exhibits very good sound dampening properties.

[0042] In an advantageous further development, the acoustically effective component has at least one through-opening and / or a stiffening section and / or an edge embossing.

[0043] Through-holes serve to route other components, such as cables, pipes or lines, Bowden cables, or the like. For example, if the acoustically effective component is located on the bulkhead of the motor vehicle, this can have a through-hole through which the intermediate steering shaft extends, connecting the motor vehicle's steering column to the steering gear.

[0044] Stiffening sections serve to increase the rigidity of the acoustically effective component. This can be achieved, for example, through ribs or beads. Thanks to these stiffening structures, the dimensional stability of the acoustically effective component can be further improved.

[0045] Edge embossing is arranged on the outer edges of the acoustically effective component, which have a reduced material thickness. Edge embossing has the advantage of improving the fit of the acoustically effective component. Furthermore, it can minimize potential sound leakage. Edge embossing contributes to the component's tight fit and thus, among other things, forms a more effective barrier against sound transmission. This can further improve the acoustic properties. In an advantageous further development, all materials of the acoustically effective component are single-material. In other words, all thermoplastic materials used in the acoustically effective component are, for example, polyethylene terephthalates.However, it may be intended that different thermoplastic materials, such as polyethylene terephthalate, be used, for example, higher-melting and low-melting thermoplastic materials, e.g., polyethylene terephthalate. Thanks to the purity of the materials, the acoustically effective component is fully recyclable. The acoustically effective component is considered pure if it contains the same or less than 1 percent by weight of other substances. In other words, the acoustically effective component is pure if it consists of at least 99.0 percent by weight of the same thermoplastic material, e.g., polyethylene terephthalate.

[0046] In an advantageous development, the acoustically effective component is thermoformable or thermoformed. Thermoforming is a manufacturing process in which the acoustically effective component is heated to a high temperature or is placed in a hot mold and then formed into a specific shape. Thanks to thermoforming, the acoustically effective component can be formed into the desired shape effectively and with high precision.

[0047] In an advantageous further development, the acoustically effective component is designed as a firewall insulation component, trunk insulation component, wheel house insulation component, door insulation component, floor assembly insulation component, or roof skin insulation component for a motor vehicle. This allows the acoustic properties inside the passenger compartment to be improved while simultaneously reducing the mass of the vehicle compared to the state of the art. Furthermore, the component is fully recyclable.

[0048] Furthermore, the object is achieved by a method according to the invention according to claim 21.

[0049] A method for producing an acoustically effective component for a motor vehicle is proposed, which method comprises the following steps: a) providing an absorber layer acting as a spring, which is designed as a nonwoven and made of a thermoplastic material, and a mass layer formed as a nonwoven and made of the same material; b) heating the absorber layer and the mass layer and placing them in a mold that is colder than the latter; or placing the absorber layer and the mass layer in a mold that is hotter than the latter; c) thermoforming the absorber layer and the mass layer by means of the mold to form the acoustically effective component, wherein the mass layer is thermoformed in such a way that the mass layer is divided by the mold into a plurality of insulated surface elements that are connected to one another via grooves.

[0050] In particular, the method according to the invention is a method for producing an acoustically effective component which is thermoformed, i.e. a method for producing a thermoformed acoustically effective component.

[0051] The first step a) of the method according to the invention provides for the preparation of the absorber layer and the mass layer. The absorber layer is formed from a nonwoven fabric made of a suitable thermoplastic material such as PET, and the mass layer is formed as a nonwoven fabric made of the same material. For example, it can be provided that these layers are already effectively connected to one another, i.e. it is already an acoustically effective component that is provided as a semi-finished product in the form of panels or cut to a specified length from a roll. Alternatively, it can be provided that the absorber layer and the mass layer are provided separately, i.e. they are not yet effectively connected to one another. These can also be provided as panels or from a roll.If provided as a roll, it would be conceivable and possible that either one roll would be required for each layer, or that both layers would be wound in a sandwich-like manner in one roll, but these layers would not be effectively connected on the roll.

[0052] The second step b) of the process according to the invention offers two alternative ways of applying heat. Either the absorber layer and the mass layer are heated before being placed in the cold mold, or the cold absorber layer and the cold mass layer are placed in a hot mold.

[0053] Thus, in the first alternative, the method according to the invention comprises the following steps: a) providing an absorber layer acting as a spring, which is formed as a nonwoven and from a thermoplastic material, and a mass layer formed as a nonwoven and from the same thermoplastic material; b) heating the absorber layer and the mass layer, and placing them in a mold that is colder than the latter; c) thermoforming the absorber layer and the mass layer by means of the mold to form the acoustically effective component, wherein the mass layer is thermoformed in such a way that the mass layer is divided by the mold into a plurality of insulated surface elements that are connected to one another via grooves.

[0054] In this first variant of step b), the absorber layer and the mass layer are heated before being inserted into the mold. This can be done, for example, using an oven or infrared radiation. The temperature of the heated absorber layer and / or the heated mass layer is intended to be higher, i.e., greater than the temperature of the mold. In other words, the mold is colder than the inserted layers. For this purpose, it can be provided, for example, that the mold is at room temperature. Alternatively, the mold can be additionally cooled or slightly preheated before the absorber layer and the mass layer are inserted.

[0055] The forming tool preferably has an upper die and a lower die in which the two layers are inserted as a blank.

[0056] Preferably, the absorber layer and / or the mass layer are heated to a temperature which is preferably between 100 and 200 °C. In the second alternative, the method according to the invention comprises the following steps: a) providing an absorber layer which acts as a spring and is designed as a nonwoven and made of a thermoplastic material, and a mass layer which is designed as a nonwoven and made of the same thermoplastic material; b) inserting the absorber layer and the mass layer into a mold which is hotter than the absorber layer, c) thermoforming the absorber layer and the mass layer by means of the mold to form the acoustically effective component, wherein the mass layer is thermoformed in such a way that the mass layer is divided by the mold into a plurality of insulated surface elements which are connected to one another via grooves.

[0057] In this second variant of step b), the absorber layer and the mass layer are inserted into the mold, with the temperature of the absorber layer and / or the mass layer being lower, i.e., lower than the temperature of the mold. In other words, the mold is hotter than the inserted layers. For this purpose, it can be provided, for example, that the absorber layer and / or the mass layer are at room temperature. Alternatively, at least one of the two layers can be additionally cooled or slightly preheated before being inserted into the mold.

[0058] The forming tool preferably has an upper die and a lower die in which the two layers are inserted as a blank.

[0059] The forming tool, i.e. the upper die and / or the lower die, has a temperature that is preferably between 160 and 230 °C.

[0060] The third step (c), which is identical in both variants, involves thermoforming the absorber layer and the mass layer. The two dies are moved toward each other, forming the absorber layer and the mass layer into the desired shape. The heat provided, either by heating the absorber layer and / or the mass layer or by the hot mold, thermoforms the two layers. The mass layer is formed in such a way that it is divided into a plurality of insulated surface elements that are connected to each other via grooves.

[0061] Thanks to the method according to the invention, the acoustically effective component can be manufactured effectively and with high precision in the appropriate shape. Furthermore, such a method according to the invention is well suited for large-scale production and can be operated with high cost-effectiveness and efficiency, thus conserving resources and being environmentally friendly.

[0062] In an advantageous development of the method, in which polyethylene terephthalate is used as the thermoplastic material, it can be provided that the absorber layer comprises multi-component fibers made of polyethylene terephthalate, wherein the multi-component fibers are at least partially melted by the heating provided in step b) or by the hotter molding tool for bonding the absorber layer and the mass layer during thermoforming in step c).

[0063] The multi-component fibers are preferably bi-component fibers. In step b), the absorber layer and / or the mass layer are heated either prior to insertion or through heat transfer when the colder absorber layer and mass layer are in the hotter mold. This heating at least partially melts the multi-component fibers, i.e., one component of the multi-component fiber melts. This melting component consists of a low-melting PET, while at least one other component of the multi-component fiber is made of a higher-melting PET. The molten component of the multi-component fiber creates an effective and resilient bond between the absorber layer and the mass layer through thermoforming. These are bonded together by a material fit. Especially after cooling, the two layers are firmly and permanently bonded.Thanks to this further development of the process, the absorber layer and the mass layer can be connected to each other easily and efficiently.

[0064] In an advantageous development of the method, in which polyethylene terephthalate is also used as the thermoplastic material, it can be provided that a thermoplastic melt film made of polyethylene terephthalate is arranged between the absorber layer and the mass layer, wherein this is at least partially melted by the heating provided in step b) or by the hotter molding tool to bond the absorber layer and the mass layer during thermoforming in step c).

[0065] The thermoplastic melt film is inserted into the mold together with the mass layer and the absorber layer. The melt film is preferably made of PET. In step b), the absorber layer and / or the mass layer and / or the melt film are heated either before insertion or through heat transfer when the colder absorber layer, mass layer, and melt film are located in the hotter mold. This heating at least partially melts the melt film. This melt film is made of a low-melting PET. Thermoforming creates an effective and resilient bond between the absorber layer and the mass layer. These are bonded together by the molten melt film, i.e., with the melt film interposed. This can also be referred to as an indirect bond.Especially after cooling, the two layers are firmly and permanently bonded together. Thanks to this refinement of the process, the absorber layer and the mass layer can be bonded together easily and efficiently.

[0066] It is conceivable and possible to combine a melt-bonded film and the absorber layer with multicomponent fibers. This results in a particularly high-strength bond between the absorber layer and the bulk layer.

[0067] In an advantageous development of the method, it can be provided that stiffening sections are formed by means of step c). For this purpose, the upper die and / or the lower die has a corresponding geometry so that the stiffening sections are formed into the acoustically effective component by the thermoforming of step c). Such stiffening sections can be designed as ribs or beads. Thanks to this development, a stiffer and more stable acoustically effective component can be produced without increased effort and in a simple and resource-saving manner. A possible alternative process for producing a component according to the invention has the following process steps: a) Providing a material composite comprising a. a mass layer acting as a mass in the component, which mass layer is formed as a fleece and from a polyethylene terephthalate, b.an absorber layer formed as a nonwoven fabric and made of a polyethylene terephthalate, and c) a vapor-tight film formed of a polyethylene terephthalate arranged between the mass layer and the absorber layer, b) placing the material composite in a hot mold, c) closing the mold, and d) generating an overpressure between the half of the mold receiving the absorber layer and the vapor-tight film, whereby the mass layer is thermoformed by the mold in such a way that the mass layer is divided into a plurality of insulated surface elements which are connected to one another via grooves.

[0068] The overpressure can be generated, for example, by evaporating water. This can be injected between the half of the mold that houses the absorber layer and the vapor-tight film. Alternatively, compressed air can be injected into this area of ​​the mold.

[0069] The process control can be further supported by creating a vacuum between the half of the mold, which receives the mass layer, and the vapor-tight film.

[0070] In an advantageous development of the aforementioned manufacturing methods, it can be provided that the absorber layer and the mass layer are processed by means of a shaping separation operation. A separation operation is understood to mean various manufacturing processes in which the local material cohesion is eliminated, i.e. reduced as a whole, by changing the shape of the acoustically effective component. In particular, the separation operation can be a punching operation. This separation operation can preferably take place between steps a) and b). Alternatively or additionally, the separation operation can take place after step c). In a particularly preferred embodiment, after the absorber layer and the mass layer have been provided, geometric shapes, for example through holes, are first punched out of the layers. After thermoforming,...In step c), the edge area of ​​the acoustically effective component is then shaped by a punching operation. These two punching operations can also be performed independently, meaning the punching operation can be performed after the component has been prepared. Step a) is not inextricably linked to a punching operation after step c). If a meltable foil is present, it can simply be punched along with the component. This has no negative effects.

[0071] Thanks to this separation process, an acoustically effective component according to the invention can be manufactured with high precision and in a resource-efficient manner. The removed elements that are no longer needed can be fully recycled thanks to the purity of the component, for example, made of PET.

[0072] A previously described method according to the invention and its advantageous further developments are preferably used to produce an acoustically effective component according to the invention and its advantageous further developments described above.

[0073] A further aspect of the invention provides a motor vehicle comprising a body having at least one vibrating surface and an acoustically effective component connected to the vibrating surface. According to the invention, the acoustically effective component is designed as an acoustically effective component according to the invention and / or is manufactured according to the method according to the invention.

[0074] Preferably, the vibrating surface is formed by a bulkhead (front wall), a floor assembly, a wheel house, a roof skin, a door or a trunk recess.

[0075] In an advantageous development, the acoustically effective component is arranged on the inside relative to a passenger compartment of the motor vehicle, i.e., inside the passenger compartment. It should be noted that the features of the specified developments and advantageous embodiments can be freely combined with one another within the scope of what is technically possible, even if this is not explicitly stated in the text. This applies in particular beyond the boundaries of the claim categories of device and method.

[0076] Further advantages and features of the acoustically effective component according to the invention emerge from the following exemplary embodiments, which are explained in more detail with reference to the figures (Figure = Fig.).

[0077] In these show:

[0078] Fig. 1 : a schematic cross-section of a first material composite for

[0079] Production of an acoustically effective component according to the invention according to a first embodiment,

[0080] Fig. 2: a schematic cross-section of a second material composite for

[0081] Production of an acoustically effective component according to the invention according to a second embodiment,

[0082] Fig. 3: a schematic cross-section of the acoustically effective component according to the invention according to a first embodiment,

[0083] Fig. 4: the component according to the invention according to Fig. 3, which is connected to a vibrating surface,

[0084] Fig. 5: a plan view of an embodiment of an acoustically effective component according to the invention based on the material composite according to Fig. 1,

[0085] Fig. 6: a section through the component from Fig. 4 along the section line IV

[0086] - IV,

[0087] Fig. 7: a section through the component from Fig. 4 along the section line V -

[0088] V, Fig. 8: a schematic cross-section of an acoustically effective component according to the invention based on the material composite of Fig. 2 with molded edge embossing, and

[0089] Fig. 9: a schematic cross-section of a multi-component fiber designed as a two-component fiber.

[0090] In the various figures, identical parts are always provided with the same reference symbols and are therefore usually named or mentioned only once.

[0091] Figure 1 shows a schematic cross-section of a composite material 10 for the production of a first embodiment of an acoustically effective component according to the invention. The composite material consists of a first nonwoven 11, which is made of PET fibers, has a material thickness of approximately 20 mm, and a basis weight of approximately 1,400 g / m2 Preferably, the first nonwoven 11 has a vertical fiber orientation. The first nonwoven 11 contains approximately 40% by weight of Bico fibers made of PET, which will be discussed in more detail below. A second nonwoven 12, which also consists of vertical PET fibers and has a material thickness of approximately 30 mm and a basis weight of approximately 450 g / m, lies loosely on the first nonwoven 11. 2 has.

[0092] The first fleece 11 is intended to form a mass layer in the ready-to-use component, the second fleece 12 to form an absorber layer.

[0093] Fig. 2 shows a schematic cross-section of a material composite 10 for the production of a second embodiment of an acoustically effective component according to the invention. The material composite 10 consists of a first nonwoven 11, which is made of PET fibers, has a material thickness of approximately 20 mm and a basis weight of approximately 1,400 g / m2 Preferably, the first nonwoven 11 has a vertical fiber orientation. In contrast to the composite material according to Fig. 1, the first nonwoven 11 in this example does not contain any bico fibers. A second nonwoven 12, which also consists of vertical PET fibers and has a material thickness of approximately 30 mm and a basis weight of approximately 450 g / m, lies loosely on the first nonwoven 11. 2 Again, the first fleece 11 is intended to form a mass layer in the ready-to-use component, the second fleece 12 to form an absorber layer.

[0094] A melt-melt film 4 made of PET with a material thickness of 30 micrometers is arranged between the first nonwoven 11 and the second nonwoven 12. The melt-melt film 4 is intended to be at least partially melted during thermoforming of the material composite, thereby captively bonding the first nonwoven 11 and the second nonwoven 12 to one another.

[0095] Fig. 3 shows a schematic cross-section of an acoustically effective component 1 according to the invention, which was obtained by thermoforming from a material composite 10 according to Fig. 1. For reasons of simplification, the inventive division of the mass layer 2 into a plurality of insulated surface elements is not shown in Fig. 3.

[0096] This component 1 has a mass layer 2 and an absorber layer 3 acting as a spring, wherein the absorber layer 3 has a first side 31 and a second side 32 opposite thereto, wherein the first side 31 is connected to the mass layer 2 and the second side 32 is designed for connection to a vibrating surface. The absorber layer 3 corresponds to the second nonwoven 12 from Fig. 1, the material thickness of which was not reduced or only insignificantly reduced during thermoforming. The absorber layer 3 is therefore designed as a nonwoven made of polyethylene terephthalate. The mass layer 2 was created during thermoforming of the material composite according to Fig. 1 by irreversible compression of the first nonwoven 11, wherein the material thickness of the first nonwoven 11 was reduced from the initial value of 20 mm to approximately 5 mm.

[0097] Component 1 consists of at least 99% PET by weight and is therefore considered to be single-material, meaning that component 1 can be fully recycled.

[0098] Fig. 4 shows the acoustically effective component 1 of Fig. 3, which is connected to a vibrating surface 100 of a motor vehicle. The connection is made by means of form-locking elements (not shown). These can be formed directly on the surface 100 or provided as a separate component. Clips and clasps, in particular, are widely used in automotive construction, are inexpensive, and easy to install. For the sake of simplicity, the inventive division of the mass layer 2 into a plurality of insulated surface elements is also not shown in Fig. 4.

[0099] As can be clearly seen from Fig. 4, the absorber layer 3 is connected to the surface 100 by its second side 32. The second side 32 is opposite the first side 31, which is effectively connected to the mass layer 2. The mass layer 2 is thus on the other side of the absorber layer 3 than the vibrating surface 100. The sound emanating from the vibrating surface thus first enters the absorber layer and is dampened there. The remaining sound that has penetrated the absorber layer 3 is stopped from propagating by the mass layer 2, which acts as a barrier. The mass layer 2 thus dampens the sound that penetrates the absorber layer 3.

[0100] Fig. 5 now shows the component 1 according to Fig. 3 in a top view, from which the inventive division of the ground layer 2 into a plurality of insulated surface elements 22, which are connected to one another via grooves 23, can be seen. In the illustrated embodiment, the insulated surface elements 22 have the shape of regular hexagons and are arranged on a hexagonal grid, so that they substantially uniformly fill the entire surface of the ground layer 2.

[0101] The insulated surface elements 21 are separated from each other by grooves 22, which are V-shaped in the illustrated embodiment. The width of the grooves 22 is approximately the same across the entire surface of the ground layer 2.

[0102] As can be seen from the sectional views of Figures 6 and 7, the local material thickness of the ground layer 2 in the grooves 23 essentially corresponds to the local material thickness in the insulated surface elements 22. Fig. 6 shows a partial sectional view of Fig. 5 along the section line IV-IV, Fig. 7 shows a partial sectional view of Fig. 5 along the section line V-V.

[0103] Both Fig. 6 and Fig. 7 show that the material thickness of the absorber layer 3 is locally reduced in the region of the grooves 22. The component according to the invention shown in Figs. 3 to 7 was manufactured by means of a thermoforming process with the process steps according to claim 22.

[0104] Fig. 8 shows a schematic cross-section of an acoustically effective component 1 according to the invention, which was obtained from a material composite according to Fig. 2 by means of thermoforming according to a method with the method steps of claim 23 and a subsequent separation operation. For reasons of simplification, the inventive division of the mass layer is also shown in Fig. 8.

[0105] 2 into a plurality of isolated surface elements not shown.

[0106] Component 1 has a through-hole 5, which was created by a cutting operation (punching). An edge embossing 6 was formed by thermoforming. The edge embossing 6 is characterized by a reduced material thickness of the absorber layer 3 and the mass layer 2 in the thickness direction.

[0107] The PET nonwoven of the mass layer 2 according to Fig. 1 comprises monocomponent fibers with a mass fraction of 80 wt% and multicomponent fibers 33 with a mass fraction of 20 wt%. The multicomponent fibers 33 are formed as bicomponent fibers and are also shown schematically in Fig. 9. For reasons of clarity, the monocomponent fibers are not shown.

[0108] The multicomponent fibers 33 of Fig. 1 are formed as sheath / core fibers. Fig. 9 shows such a fiber 33 in cross-section. The fiber 33 has a sheath 331 formed from a polyethylene terephthalate. This has a lower melting temperature than the polyethylene terephthalate from which the core 332 of the fiber 33 is formed.

[0109] The mass layer 2 of Fig. 1 formed from the nonwoven fabric can be effectively bonded to the absorber layer 3 without any additional bonding means by melting the sheath 331 of the fibers 33 formed from the low-melting PET by heating and effectively bonding it to the absorber layer 3. In other words, the first side 31 of the absorber layer

[0110] 3 are firmly and permanently bonded to the mass layer 2. The core 332, consisting of the high-melting PET, does not melt and thus ensures sufficient stability of the nonwoven fabric forming the mass layer 2. Reference numeral

[0111] 1 Acoustically effective component

[0112] 10 Material composite

[0113] 11 first fleece

[0114] 12 second fleece

[0115] 2 ground layer

[0116] 21 Outside

[0117] 22 Surface element

[0118] 23 grooves

[0119] 3 Absorber layer

[0120] 31 first page

[0121] 32 second page

[0122] 33 multicomponent fiber

[0123] 331 Coat

[0124] 332 core

[0125] 4 melt foil

[0126] 5 passage opening

[0127] 6 Edge embossing

[0128] 100 vibrating surface

Claims

Patent claims 1. Acoustically effective component (1) for a motor vehicle, comprising a mass layer (2) and an absorber layer (3) acting as a spring, wherein the absorber layer (3) has a first side (31) and a second side (32) opposite thereto, wherein the first side (31) is connected to the mass layer (2) and the second side (32) is designed for connection to a vibrating surface (100), wherein the absorber layer (3) is designed as a nonwoven and from a thermoplastic material, characterized in that the mass layer (2) is formed from a compacted nonwoven made of the same material, wherein the mass layer (2) is divided into a plurality of insulated surface elements (22) which are connected to one another via grooves (23).

2. Acoustically effective component (1) according to claim 1, characterized in that the insulated surface elements (22) have the shape of regular polygons.

3. Acoustically effective component (1) according to one of the preceding claims, characterized in that the grooves (23) are W-shaped, V-shaped or semi-circular or semi-ellipsoidal.

4. Acoustically effective component (1) according to one of the preceding claims, characterized in that the local material thickness of the mass layer (2) in the grooves (23) substantially corresponds to the local material thickness in the insulated surface elements (22).

5. Acoustically effective component (1) according to one of the preceding claims, characterized in that the thermoplastic material is polyethylene terephthalate.

6. Acoustically effective component (1) according to claim 5, characterized in that at least one nonwoven comprises multi-component fibers (33) made of polyethylene terephthalate, preferably both.

7. Acoustically effective component (1) according to claim 6, characterized in that the multi-component fibers (33) have a mass fraction which is 15% - 25% of the total mass of the fleece in question, preferably about 20%.

8. Acoustically effective component (1) according to claim 6, characterized in that the multi-component fibers (33) are designed as a sheath / core fiber, wherein the sheath (331) of the fibers is formed from a polyethylene terephthalate which has a lower melting temperature than a polyethylene terephthalate from which the core (332) of the fibers is formed.

9. Acoustically effective component (1) according to claim 6, characterized in that the multi-component fibers (33) are designed as side-by-side fibers and / or sheath / core fibers and / or matrix / fibril fibers and pie-piece fibers.

10. Acoustically effective component (1) according to one of the preceding claims, characterized in that the absorber layer has a density which is lower than a density of the mass layer.

11. Acoustically effective component (1) according to claim 5, characterized in that a thermoplastic melt film (4) is arranged between the absorber layer (3) and the mass layer (2).

12. Acoustically effective component (1) according to claim 11, characterized in that the melt film (4) is formed from a polyethylene terephthalate.

13. Acoustically effective component (1) according to one of the preceding claims, characterized in that the absorber layer (3) has a thickness between 1 and 35 mm.

14. Acoustically effective component (1) according to one of the preceding claims, characterized in that the mass layer (2) has a thickness between 1 and 10 mm.

15. Acoustically effective component (1) according to one of the preceding claims, characterized in that the absorber layer (3) has a surface weight between 400 and 800 g / m 2 has.

16. Acoustically effective component (1) according to one of the preceding claims, characterized in that the mass layer (2) has a density between 100 kg / m 3 and 200 kg / m 3 has.

17. Acoustically effective component (1) according to one of the preceding claims, characterized in that the mass layer (2) has a surface weight between 1,200 g / m 2 and 1,600 g / m 2 has.

18. Acoustically effective component (1) according to one of the preceding claims, characterized in that it has at least one through-opening (5) and / or a stiffening section (5) and / or an edge embossing (7).

19. Acoustically effective component (1) according to one of the preceding claims, characterized in that all materials of the component (1) are of the same type.

20. Acoustically effective component (1) according to one of the preceding claims, characterized in that it is thermoformable or thermoformed.

21. Acoustically effective component (1) according to one of the preceding claims, characterized in that it is designed as a bulkhead insulation component, trunk insulation component, door insulation component, wheel house insulation component, floor assembly insulation component or as a roof skin insulation component for a motor vehicle.

22. Method for producing an acoustically effective component (1) for a motor vehicle, comprising the following method steps: a) providing a mass layer (2) which acts as a mass in the component and is designed as a fleece and from a thermoplastic material, b) heating the mass layer, c) combining the warm mass layer with a cold absorber layer (3) which is designed as a fleece and from the same thermoplastic material, d) inserting the material composite of warm mass layer and cold absorber layer (3) into a mold (8) which is colder than the mass layer; e) thermoforming the material composite by means of the molding tool (8) to form the acoustically effective component (1), wherein the mass layer (2) is thermoformed in such a way that the mass layer (2) is divided by the molding tool (8) into a plurality of insulated surface elements (22) which are connected to one another via grooves (23).

23. A method for producing an acoustically effective component (1) for a motor vehicle, comprising the following method steps: a) providing a material composite (10) comprising a. a mass layer (2) acting as a mass in the component, which mass layer is formed as a nonwoven fabric (11) and from a polyethylene terephthalate, b. an absorber layer (3) which is formed as a nonwoven fabric (12) and from a polyethylene terephthalate, and c.a vapor-tight film made of polyethylene terephthalate arranged between the mass layer (2) and the absorber layer (3), b) inserting the material composite (10) into a hot mold, c) closing the mold, and d) generating an overpressure between the half of the mold that accommodates the absorber layer (3) and the vapor-tight film, whereby the mass layer (2) is thermoformed by the mold in such a way that the mass layer (2) is divided into a plurality of insulated surface elements (22) which are connected to one another via grooves (23).

24. Method according to claim 23, characterized in that the overpressure is generated by evaporating water which is injected between the half of the molding tool receiving the absorber layer and the vapor-tight film.

25. Method according to claim 23, characterized in that the overpressure is generated by blowing compressed air between the half of the molding tool receiving the absorber layer and the vapor-tight film.

26. Experience according to claim 23, characterized in that a negative pressure is created between the half of the mold receiving the mass layer and the vapor-tight film.

27. The method according to claim 22, characterized in that the absorber layer (3) comprises multi-component fibers (33) made of polyethylene terephthalate, wherein the multi-component fibers (33) are at least partially melted by the heating provided in step b) or by the hotter molding tool (8) for joining the absorber layer (3) and the mass layer (2) during thermoforming.

28. Method according to one of claims 22 or 23, characterized in that a thermoplastic melt film (4) made of polyethylene terephthalate is arranged between the absorber layer (3) and the mass layer (2), said film being at least partially melted by the heating provided in step b) or by the hotter molding tool (8) to bond the absorber layer (3) and the mass layer (2) during thermoforming.

29. Method according to one of claims 22 to 28, characterized in that the absorber layer (3) and the mass layer (2) are processed by means of a shaping separation operation.

30. Method according to one of claims 22 to 29, characterized in that the acoustically effective component (1) is designed according to one of claims 1 to 21.

31. Motor vehicle, comprising a body which has at least one vibrating surface (100), and an acoustically effective component (1) which is connected to the vibrating surface (100), characterized in that the acoustically effective component (1) is designed according to one of claims 1 to 21 and / or is manufactured according to one of claims 22 to 30.

32. Motor vehicle according to claim 31, characterized in that the oscillating surface (100) is formed by a bulkhead, a floor assembly, a wheel house, a roof skin, a door or a trunk recess.

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