Acoustically active component for a motor vehicle and a method for producing same

Abstract

The invention relates to an acoustically active component (1) for a motor vehicle, comprising a heavy 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 heavy layer (2) and the second side (32) is designed for connection to an oscillating surface (100), wherein the absorber layer (3) is formed as a nonwoven and from a polyethylene terephthalate. According to the invention, the heavy layer (2) is made of a polyester. The invention further relates to a method for producing an acoustically active 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 heavy 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 heavy layer and the second side is designed for connection to a vibrating surface, wherein the absorber layer is designed as a nonwoven and made of a 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 heavy layer, the absorber layer being formed as a nonwoven made of polyethylene terephthalate. The heavy layer is formed from a variety of different material families. 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 claim 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 heavy layer and an absorber layer acting as a spring. The absorber layer has a first side and a second side opposite the first side. The first side is connected to the heavy layer and the second side is configured for connection to a vibrating surface. The absorber layer is formed as a nonwoven and made of a polyethylene terephthalate. According to the invention, the heavy layer is formed of a polyester.

[0010] Thanks to the solution according to the invention, an acoustically effective component can be provided that has a lower mass than components known from the prior art and is simultaneously very easily recyclable without adversely affecting the acoustic properties, thus offering very good acoustic properties. Because the heavy layer is made of a polyester, 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, since both the absorber layer and the heavy layer are made of polyester. The absorber layer is made of polyethylene terephthalate (PET), which is a polyester, i.e., belongs to the polyester material family. Thus, unlike the prior art, there is no composite material made of a wide variety of material families that are hardly or not at all recyclable, since these individual, different material families are almost inseparably connected to one another. According to the invention, the individual layers are made of the same material family, i.e., polyester, resulting in a monomaterial structure.

[0011] Both the absorber layer and the heavy layer may contain a small proportion of substances other than polyester, but this does not affect the recyclability of the acoustically effective component. Typically, these substances are technically not particularly detrimental and / or represent minimal impurities in the polyester materials of the absorber layer and the heavy 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 polyester heavy layer, that is designed (and designed 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 it using separate clasps or clips. The acoustically effective component represents a spring-mass system, in which the absorber layer is the spring and the heavy layer forms the mass of the spring-mass system. The absorber layer serves to dampen sound. The heavy layer, on the other hand, is intended for sound insulation.

[0015] 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 heavy layer thus preferably forms an acoustic barrier.

[0016] 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 heavy layer, i.e., dampened.

[0017] The absorber layer and the heavy layer are connected to each other directly or indirectly. An indirect connection occurs when one or more additional layers are arranged between the absorber layer and the heavy layer.

[0018] 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.

[0019] In an advantageous embodiment, the heavy layer is made of polyethylene terephthalate (PET) and / or polybutylene terephthalate (PBT). Tests have shown that both a heavy layer made of PET and a heavy layer made of PBT, as well as a combination of PET and PBT, exhibit excellent insulating properties.

[0020] In an advantageous embodiment, the heavy layer is formed from a polyethylene terephthalate foam. For the purposes of the invention, a polyethylene terephthalate foam is understood to be a foam made of polyethylene terephthalate, referred to as PET foam for short. Thanks to the PET foam design, the acoustically effective component can provide consistently good acoustic properties, despite a significant reduction in mass, similar to the significantly heavier acoustically effective components of the prior art.

[0021] In a further advantageous embodiment, the heavy layer is formed from a polybutylene terephthalate film. For the purposes of the invention, the polybutylene terephthalate film is understood to be a film made of polybutylene terephthalate (PBT). Thanks to the PBT film design, the acoustically effective component can provide significantly improved acoustic properties compared to prior art acoustically effective components, despite a significant reduction in mass. Thus, a lighter component can provide better acoustic properties than those of the prior art.

[0022] The heavy layer can be provided with multiple layers, with one layer preferably made of PET and another layer made of PBT. Particularly preferably, one layer can be made of PET foam and another layer of PBT film. This allows the acoustic properties to be further improved.

[0023] Preferably, the PET foam or PBT film is dimensionally stable, meaning it does not deform due to its own mass.

[0024] The PET of the absorber layer can preferably differ from the PET of the heavy layer. In other words, although both layers are made of the same PET, they are different PET variants.

[0025] In a particularly advantageous embodiment, the heavy layer can be formed from several sublayers or plies, all of which are made of a PET foam or a PBT film. These can all be made of the same type of PET foam or PBT film, or they can be made of different types of PET foam or PBT film.

[0026] In an advantageous refinement, the polyethylene terephthalate foam is a closed-cell polyethylene terephthalate foam. The cells of the PET foam are thus insulated from one another. This closed-cell structure offers the advantage that the heavy layer exhibits high dimensional stability and improved acoustic insulation properties.

[0027] The nonwoven preferably comprises 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. The nonwoven may be formed entirely from monocomponent fibers.

[0028] The nonwoven fabric may comprise multi-component fibers made of polyethylene terephthalate. Multi-component fibers consist of two or more different PET materials combined with one another. Preferably, the nonwoven fabric comprises bicomponent fibers made of polyethylene terephthalate. The bicomponent fiber is a multi-component fiber; this consists of exactly two different PET materials and is also referred to as bico fibers. Particularly preferably, the multi-component fibers or bicomponent fibers comprise a low-melting PET and a high-melting PET, i.e., the melting point of the low-melting PET is lower than the melting point of the high-melting PET.This offers the advantage that the absorber layer formed from the nonwoven fabric can be effectively bonded to the heavy layer without additional bonding agents. The low-melting PET of the nonwoven fabric is melted through heating and effectively bonds with the heavy layer. In other words, the first side of the absorber layer can be firmly and permanently bonded to the heavy layer. The high-melting PET does not melt, thus ensuring sufficient stability.

[0029] Particularly preferably, the multi-component fibers or the bi-component fibers have a mass fraction that amounts to a maximum of 40% 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 heavy 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. In an advantageous development, the multi-component fibers or the bi-component fibers are designed as sheath / core fibers, wherein the sheath of the fibers is formed from a polyethylene terephthalate that has a lower melting temperature than the polyethylene terephthalate from which the core of the fibers is formed.Thanks to this design, the nonwoven absorber layer can be effectively bonded to the heavy layer without the need for additional bonding agents. The low-melting PET jacket melts through heating, effectively bonding it to the heavy layer. In other words, the first side of the absorber layer can be firmly and permanently bonded to the heavy layer. The high-melting PET core does not melt, thus ensuring sufficient stability.

[0030] 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.

[0031] 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, the absorber layer formed from the nonwoven fabric can be effectively bonded to the heavy layer without additional bonding agents, as the component formed from the low-melting PET is melted by heating and effectively bonded to the heavy layer. In an advantageous further development, the absorber layer has a surface density that is lower than the surface density of the heavy layer. The surface density of the absorber layer is thus lower than that of the heavy 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 heavy layer.

[0032] In a further advantageous development, a thermoplastic melt film is arranged between the absorber layer and the heavy layer. Thanks to the melt film, the absorber layer and the heavy layer can be firmly bonded to one another by applying heat to the melt film, which then firmly bonds the absorber layer and the heavy layer after cooling. The first side of the absorber layer can thus be firmly and permanently bonded to the heavy 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 heavy layer. The melt film is preferably thinner than the absorber layer and / or the heavy layer.

[0033] In an advantageous refinement, the absorber layer generally has a thickness between 5 and 35 mm. A thickness between 15 and 25 mm has proven particularly effective for automotive applications. In some cases, the thickness of the absorber layer can also be less than 5 mm. Studies have shown that an absorber layer in this thickness range offers an optimum balance between acoustic damping properties and mass.

[0034] In a preferred embodiment, the heavy layer made of polybutylene terephthalate has a thickness between 1 and 2 mm, or the heavy layer made of polyethylene terephthalate has a thickness between 2.5 and 5 mm. Numerous tests have shown that a heavy layer in such a thickness range offers an optimum balance between acoustic insulation properties and mass.

[0035] In a further advantageous development, the absorber layer has a surface density between 400 g / m 2 and 800 g / m 2 Thanks to such a surface 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.

[0036] In an advantageous embodiment, the heavy layer has a density between 100 kg / m 3 and 200 kg / m 3 Thanks to this density, the heavy layer exhibits excellent sound barrier properties. It has been shown that such a heavy layer, acting as the mass of the spring-mass system, exhibits very good sound dampening properties.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] Edge embossing is applied to 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 helps ensure that the component fits tightly and thus, among other things, forms a more effective barrier against sound transmission. This can further improve the acoustic properties.

[0041] In an advantageous development, all materials of the acoustically effective component are single-material. In other words, all materials used in the acoustically effective component belong to the polyester material family, so that the acoustically effective component has a monomaterial structure. However, it can be provided that different polyesters, in particular different polyethylene terephthalates and / or different polybutylene terephthalates, for example higher-melting and low-melting polyethylene terephthalates or polybutylene terephthalates, are used. Thanks to the single-material purity, the acoustically effective component is fully recyclable. The acoustically effective component is considered single-material if it contains less than or equal to 1 percent by weight of substances other than polyester. In other words, the acoustically effective component is single-material if it consists of at least 99.0 percent polyester by weight.

[0042] 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.

[0043] In an advantageous further development, the acoustically effective component is designed as a firewall insulation component, trunk 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, full recycling is ensured.

[0044] Furthermore, the object is achieved by a method according to the invention according to claim 23.

[0045] A method for producing an acoustically effective component for a motor vehicle is proposed, which comprises the following method steps: a) providing an absorber layer acting as a spring, which is formed as a nonwoven and from a polyethylene terephthalate, and a heavy layer formed from a polyester; b) heating the absorber layer and the heavy layer, and placing them in a mold that is colder than the latter; or placing the absorber layer and the heavy layer in a mold that is hotter than the latter; c) thermoforming the absorber layer and the heavy layer by means of the mold to form the acoustically effective component.

[0046] In particular, the method according to the invention is a method for producing a thermoformed acoustically effective component, i.e., a method for producing a thermoformed acoustically effective component. In principle, an acoustically effective component according to the invention can also be produced without being thermoformed, for example, if no special shape is required, for example, if the vibrating surface is a flat surface.

[0047] The first step a) of the method according to the invention provides for the provision of the absorber layer and the heavy layer. The absorber layer is formed from a PET nonwoven fabric and the heavy layer is formed from a polyester, which can in particular be designed as a PET foam and / or a PBT film. 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 as a piece cut to a specified length from a roll. Alternatively, it can be provided that the absorber layer and the heavy 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.

[0048] The second step b) of the method according to the invention has two alternative options for heat input. Either the absorber layer and the heavy layer are heated before being inserted into the cold mold, or the cold absorber layer and the cold heavy layer are inserted into a hot mold. Thus, in the first alternative, the method according to the invention has the following steps: a) providing an absorber layer acting as a spring, which is formed as a nonwoven and made of a polyethylene terephthalate, and a heavy layer made of a polyester; b) heating the absorber layer and the heavy layer and inserting them into a mold that is cooler than the latter; c) thermoforming the absorber layer and the heavy layer using the mold to form the acoustically effective component.

[0049] In this first variant of step b), the absorber layer and the heavy 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 heavy 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 heavy layer are inserted.

[0050] The forming tool preferably has an upper die and a lower die in which the two layers are inserted as a blank.

[0051] The absorber layer and / or the heavy layer is heated to a temperature that is preferably between 100 and 200 °C.

[0052] In the second 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 made of a polyethylene terephthalate, and a heavy layer formed of a polyester; b) inserting the absorber layer and the heavy layer into a mold that is hotter than the absorber layer; c) thermoforming the absorber layer and the heavy layer by means of the mold to form the acoustically effective component.

[0053] In this second variant of step b), the absorber layer and the heavy layer are inserted into the mold, with the temperature of the absorber layer and / or the heavy 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 heavy 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.

[0054] The forming tool preferably has an upper die and a lower die in which the two layers are inserted as a blank.

[0055] The forming tool, i.e. the upper die and / or the lower die, has an elevated temperature, which is preferably between 160 and 230 °C.

[0056] The third step (c), which is identical in both variants, involves thermoforming the absorber layer and the heavy layer. The two dies are moved toward each other, forming the absorber layer and the heavy layer into the desired shape. The heat provided, either by heating the absorber layer and / or the heavy layer or by the hot mold, thermoforms the two layers.

[0057] Thanks to the method according to the invention, the acoustically effective component can be manufactured effectively and with high precision in the required 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 protecting the environment.

[0058] In an advantageous development of the method, 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 heavy layer during thermoforming in step c).

[0059] The multi-component fibers are preferably bi-component fibers. In step b), the absorber layer and / or the heavy layer are heated either prior to insertion or through heat transfer when the colder absorber layer and heavy layer are located in the hotter mold. This heating at least partially melts the multi-component fibers, meaning 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 heavy 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 heavy layer can be connected to each other easily and efficiently.

[0060] In an advantageous development of the method, it can be provided that a thermoplastic melt film made of polyethylene terephthalate is arranged between the absorber layer and the heavy 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 heavy layer during thermoforming in step c).

[0061] The thermoplastic melt film is inserted into the mold together with the heavy layer and the absorber layer. The melt film is preferably made of PET. In step b), the absorber layer and / or the heavy layer and / or the melt film are heated either before insertion or through heat transfer when the colder absorber layer, heavy 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 heavy 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 heavy layer can be bonded together easily and efficiently.

[0062] 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 heavy layer.

[0063] 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 have a corresponding geometry so that the stiffening sections are formed into the acoustically effective component by the thermoforming in 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.

[0064] In an advantageous development of the method, the absorber layer and the heavy layer can be processed by means of a shaping separation operation. A separation operation refers to various manufacturing processes in which the local material cohesion is eliminated, i.e., reduced overall, by changing the shape of the acoustically effective component. In particular, the separation operation can be a punching operation.

[0065] 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 heavy layer have been provided, geometric shapes, for example through holes, are first punched out of the layers. After thermoforming (eg step c), the edge region of the acoustically effective component is then shaped by a punching operation. These two punching operations can also take place separately, i.e. the punching operation after the provision (eg step a) is not inextricably linked to a punching operation after step c). If a melt film is present, it can simply be punched out at the same time. This has no negative effects.

[0066] 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 polyester.

[0067] 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.

[0068] 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.

[0069] Preferably, the vibrating surface is formed by a bulkhead (front wall), a floor assembly, a roof skin, a door or a trunk recess.

[0070] In an advantageous further development, the acoustically effective component is arranged on the inside relative to a passenger compartment of the motor vehicle, i.e. in the interior of the passenger compartment.

[0071] 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. 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.).

[0072] In these show:

[0073] Fig. 1 : a schematic cross-section of an acoustically effective component according to the invention,

[0074] Fig. 2: a schematic cross-section of the acoustically effective component according to the invention according to Fig. 1, which is connected to a vibrating surface,

[0075] Fig. 3: a schematic cross-section of the acoustically effective component according to the invention according to Fig. 1 after thermoforming,

[0076] Fig. 4: a schematic cross-section of a second embodiment of an acoustically effective component according to the invention, which is inserted into a mold,

[0077] Fig. 5: a schematic cross-section of an absorber layer and a

[0078] Heavy layer, which is inserted into a mold,

[0079] Fig. 6: a schematic cross-section of an acoustically effective component according to the invention in a third embodiment,

[0080] Fig. 7: a schematic cross-section of an acoustically effective component according to the invention, as shown in Fig. 6, with molded-in edge embossing,

[0081] Fig. 8: a schematic cross-section of an acoustically effective component according to the invention in a fourth embodiment, and

[0082] Fig. 9: A schematic cross-section of a multicomponent fiber designed as a bicomponent fiber. In the various figures, identical parts are always provided with the same reference numerals and are therefore generally named or mentioned only once.

[0083] Fig. 1 shows a schematic cross-section of an acoustically effective component 1 according to the invention. This component 1 comprises a heavy layer 2 and an absorber layer 3 acting as a spring. The absorber layer 3 has a first side 31 and a second side 32 opposite it. The first side 31 is connected to the heavy layer 2 and the second side 32 is designed for connection to a vibrating surface. The absorber layer 3 is formed as a nonwoven made of polyethylene terephthalate. According to the invention, the heavy layer 2 is formed from a polyester.

[0084] In this design variant, the heavy layer is formed as a closed-cell polyethylene terephthalate foam, with a density of 100 kg / m 3 The areal density of the absorber layer, which is formed by a PET fleece, is 600 g / m 2 , which corresponds to a density of about 24 kg / m 3Thus, the density of heavy layer 2 is significantly greater than the density of absorber layer 3. The thickness of the absorber layer is 25 mm and that of the heavy layer is 5 mm.

[0085] Component 1 consists of at least 99% polyester by weight and is therefore considered single-material, meaning that component 1 can be fully recycled. In this specific example, the component even consists of 99% PET by weight.

[0086] Figure 2 shows the acoustically effective component 1 of Figure 1, 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 clamps, in particular, are widely used in automotive construction, are inexpensive, and easy to install.

[0087] As can be clearly seen from Fig. 2, the absorber layer 3 is connected to the surface 100 by its second side 32. The second side 32 lies opposite the first side 31, which is effectively connected to the heavy layer 2. The heavy layer 2, which is a PET foam, is thus located 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 heavy layer 2, which acts as a barrier. The heavy layer 2 thus dampens the sound that penetrates the absorber layer 3.

[0088] Fig. 3 shows a schematic cross-section of the acoustically effective component according to the invention (see Fig. 1) after thermoforming. The component 1 (see Fig. 1) has a flat, plate-shaped structure. This can be formed by thermoforming. Thus, the acoustically effective component (see Fig. 3) can be manufactured using the method according to the invention.

[0089] For this purpose, the component 1 according to Fig. 1 is heated and placed in a cold mold. Alternatively, the component according to Fig. 1 can also be placed in a hot mold in a cold state. After forming, the shape of the component 1 has changed according to the mold. Fig. 3 shows an acoustically effective component 1 which was produced from the component 1 in Fig. 1 by means of thermoforming, wherein this component 1 has a stiffening section 6 designed as a rib. The rib forms an outwardly projecting projection on the second side 32 of the absorber layer 3. The outer side 21 of the heavy layer 2 has a molded-in bead 61. The opposite rib is formed by molding the bead 61. The component 1 in Fig. 3 is manufactured by means of the method according to the invention.The rib can be engaged with a bead (not shown) of a vibrating surface (not shown) of a motor vehicle body. Thus, the rib can not only be used to stiffen component 1, but also to facilitate assembly by serving as a positioning device. Furthermore, such a rib can ensure that component 1 is mounted in the correct installation position and effectively prevent incorrect installation (poka-yoke measure). This prevents the heavy layer from being accidentally mounted on the vibrating surface due to incorrect installation.

[0090] Fig. 4 shows a schematic cross-section of an acoustically effective component 1 according to the invention in a second embodiment variant, which is inserted into a mold 8. The absorber layer 3 and the heavy layer 2 are already effectively connected to one another. The heavy layer is formed from a PTB film. Thus, Fig. 4 shows an acoustically effective component 1 before thermoforming. The mold 8 comprises an upper die 81 and a lower die 82, wherein the upper die 81 is displaceable relative to the lower die 82, i.e., the latter can be moved towards the lower die 82. The upper die 81 and the lower die 82 are electrically heatable, wherein the temperature of the upper die 81 and the lower die 82 can be adjusted separately. Not shown, the mold 8 can be coupled to a vacuum pump or compressed air pump, wherein at least one of the dies has corresponding channels. The use of vacuum or compressed air during thermoforming is optional.

[0091] Fig. 5 shows a schematic cross-section of an absorber layer 3 and a heavy layer 2, which are inserted into a mold 8. The absorber layer 3 and the heavy layer 2 are not yet effectively bonded to one another. The heavy layer 2 is formed from a PET foam. This only occurs through thermoforming, with Fig. 5 showing the two layers 2, 3 before thermoforming and the resulting bonding of these layers 2, 3. The mold 8 comprises an upper die 81 and a lower die 82, with the upper die 81 being displaceable relative to the lower die 82, i.e., the latter can be moved toward the lower die 82. The upper die 81 and the lower die 82 are electrically heatable, with the temperature of the upper die 81 and the lower die 82 being separately adjustable. Here in Fig. 5, however, the electric heating of the dies is switched off, so that the mold is cold.However, the inserted absorber layer 3 and the heavy layer 2 were heated prior to insertion. This was done using a furnace (not shown). The mold 8 in Fig. 5 corresponds entirely to that in Fig. 4.

[0092] Fig. 6 shows a schematic cross-section of an acoustically effective component 1 according to the invention in a third embodiment. This component 1 has a heavy layer 2 and an absorber layer 3 acting as a spring. The absorber layer 3 comprises a first side 31 and a second side 32 opposite this, wherein the first side 31 is indirectly connected to the heavy layer 2 with the interposition of a thermoplastic melt film 4. The absorber layer 3 is designed as a nonwoven made of polyethylene terephthalate. The heavy layer 2 is made of a polyester. The melt film is arranged between the absorber layer 3 and the heavy layer 2 and effectively connects them together. The melt film consists of a low-melting PET. This was melted by heating so that the heavy layer 2 and the absorber layer 3 are effectively connected to one another. The connection is thus materially bonded.

[0093] Fig. 7 shows a schematic cross-section of the acoustically effective component 1 according to the invention shown in Fig. 6, which was processed by means of a separating operation and thermoforming. The component 1 has a through-opening 5, which was created by means of a separating operation (punching). An edge embossment 7 was formed by means of thermoforming. The edge embossment 7 is characterized by a reduced material thickness of the absorber layer 3 and the heavy layer 2 in the thickness direction.

[0094] Fig. 8 shows a schematic cross-section of an acoustically effective component 1 according to the invention in a fourth embodiment. This component 1 comprises a heavy layer 2 and an absorber layer 3 acting as a spring. The absorber layer 3 has a first side 31 and a second side 32 opposite it, the first side 31 being connected to the heavy layer 2. The absorber layer 3 is formed as a nonwoven made of polyethylene terephthalate, and the heavy layer 2 is made of polyester.

[0095] The PET nonwoven of the absorber layer 3 comprises single-component fibers with a mass fraction of 80 wt% and multi-component fibers 33 with a mass fraction of 20 wt%. The multi-component fibers 33 are formed as bicomponent fibers and are also shown schematically in Fig. 8. For reasons of clarity, the single-component fibers are not shown.

[0096] The multicomponent fibers 33 of Fig. 8 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.

[0097] The absorber layer 3 formed from the nonwoven fabric shown in Fig. 8 can be effectively bonded to the heavy layer 2 without additional bonding agents by heating the sheath 331 of the fibers 33 formed from the low-melting PET and effectively bonding it to the heavy layer 2. In other words, the first side 31 of the absorber layer 3 can thus be firmly and permanently bonded to the heavy layer 2. The core 332 consisting of the high-melting PET does not melt in the process, thus ensuring sufficient stability.

[0098] Reference symbol

[0099] 1 Acoustically effective component

[0100] 2 heavy layer

[0101] 21 Outside

[0102] 3 Absorber layer

[0103] 31 first page

[0104] 32 second page

[0105] 33 multicomponent fiber

[0106] 331 Coat

[0107] 332 core

[0108] 4 melt foil

[0109] 5 passage opening

[0110] 6 stiffening section

[0111] 61 bead

[0112] 7 Edge embossing

[0113] 8 mold tool

[0114] 81 Upper die

[0115] 82 Lower die

[0116] 100 vibrating surface

Claims

Patent claims 1. Acoustically effective component (1) for a motor vehicle, comprising a heavy 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 heavy 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 polyethylene terephthalate, characterized in that the heavy layer (2) is formed from a polyester.

2. Acoustically effective component (1) according to claim 1, characterized in that the heavy layer is formed from a polyethylene terephthalate and / or a polybutylene terephthalate.

3. Acoustically effective component (1) according to one of the preceding claims, characterized in that the heavy layer (2) is formed from a polyethylene terephthalate foam.

4. Acoustically effective component (1) according to one of the preceding claims, characterized in that the heavy layer (2) is formed from a polybutylene terephthalate film.

5. Acoustically effective component (1) according to one of the preceding claims, characterized in that the heavy layer (2) forms an acoustic barrier.

6. Acoustically effective component (1) according to one of claims 3 to 5, characterized in that the polyethylene terephthalate foam is a closed-cell polyethylene terephthalate foam.

7. Acoustically effective component (1) according to one of the preceding claims, characterized in that the nonwoven fabric comprises single-component fibers made of polyethylene terephthalate.

8. Acoustically effective component (1) according to one of the preceding claims, characterized in that the nonwoven fabric comprises multi-component fibers (33) made of polyethylene terephthalate.

9. Acoustically effective component (1) according to claims 7 and 8, characterized in that the multi-component fibers (33) have a mass fraction which amounts to a maximum of 40% of the total mass of the fleece.

10. Acoustically effective component (1) according to claim 8 or 9, 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.

11. Acoustically effective component (1) according to one of claims 8 to 10, 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.

12. Acoustically effective component (1) according to one of the preceding claims, characterized in that the absorber layer (3) has a surface density which is lower than a surface density of the heavy layer.

13. Acoustically effective component (1) according to one of the preceding claims, characterized in that a thermoplastic melt film (4) is arranged between the absorber layer (3) and the heavy layer (2).

14. Acoustically effective component (1) according to one of the preceding claims, characterized in that the melt film (4) is formed from a polyethylene terephthalate.

15. Acoustically effective component (1) according to one of the preceding claims, characterized in that the absorber layer (3) has a thickness between 5 and 35 mm.

16. Acoustically effective component (1) according to one of the preceding claims, characterized in that the heavy layer (2) made of polybutylene terephthalate has a thickness between 1 and 2 mm or that the heavy layer (2) made of polyethylene terephthalate has a thickness between 2.5 and 5 mm.

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

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

19. 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).

20. 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.

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

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

23. A method for producing an acoustically effective component (1) for a motor vehicle, comprising the following method steps: a) providing an absorber layer (3) acting as a spring, which is designed as a nonwoven and made of a polyethylene terephthalate, and a heavy layer (2) made of a polyester; b) heating the absorber layer (3) and the heavy layer (2) and placing them in a mold (8) that is colder than the latter; or placing the absorber layer (3) and the heavy layer (2) in a mold (8) that is hotter than the latter; c) thermoforming the absorber layer (3) and the heavy layer (2) by means of the mold (8) to form the acoustically effective component (1).

24. The method according to claim 23, 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 heavy layer (2) during the thermoforming in step c).

25. The method according to claim 23 or 24, characterized in that a thermoplastic melt film (4) made of polyethylene terephthalate is arranged between the absorber layer (3) and the heavy 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 heavy layer (2) during the thermoforming in step c).

26. Method according to one of claims 23 to 25, characterized in that stiffening sections (6) are formed by means of step c).

27. Method according to one of claims 23 to 26, characterized in that the absorber layer (3) and the heavy layer (2) are processed by means of a shaping separation operation.

28. Method according to one of claims 23 to 27, characterized in that the acoustically effective component (1) is designed according to one of claims 1 to 22.

29. Motor vehicle, comprising a body having at least one vibrating surface (100), and an acoustically effective component (1) connected to the vibrating surface (100), characterized in that the acoustically effective component (1) is designed according to one of claims 1 to 22 and / or is manufactured according to one of claims 23 to 28.

30. Motor vehicle according to claim 29, 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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