Method and insulation element for reducing the natural vibrations of a component

Abstract

Method for reducing the natural vibrations of a component (2), characterized in that a vibration behavior of the component (2) is determined and that at determined positions with vibration amplitudes which exceed a predetermined limit value, an insulating element (1) is locally fastened, which is designed as a multi-layer adhesive element with a carrier layer (1.1) and a self-adhesive damping mass (1.2), and that a region of the component (2) with a high vibration amplitude is stiffened with a precisely fitting insulating element or several insulating elements.

Description

[0001] The invention relates to a method for reducing the natural vibrations of a component and an insulating element for reducing the natural vibrations of a component.

[0002] It is well known from the prior art that driving noise in the interior of a vehicle can be reduced by applying various acoustic materials, such as insulation mats and sprayable acoustic compounds, to vehicle components. To create insulation using insulation mats, large-area mats are placed on the vehicle component at a specific location and melt onto the substrate at subsequent process temperatures. This locally stiffens the vehicle component.

[0003] Furthermore, it is generally known from the prior art that during the manufacture of a vehicle body, openings in body components are used to carry out various work steps, such as fixing the body components and implementing corrosion protection measures. During corrosion protection work, the openings are provided for the supply of paint during dip painting and / or as drain holes for excess paint. Alternatively or additionally, wax for cavity preservation and the removal of excess wax are achieved via the openings. To achieve a low noise level and a tight vehicle seal, the openings are closed again during the further production process. The openings are closed and sealed manually, for example, using plugs or adhesive elements, also known as adhesive pads.

[0004] Such an adhesive element is known from DE 10 2008 050 772 A1. The adhesive element is formed from a multilayer carrier film and a self-adhesive damping compound, the damping compound being butyl rubber. A paintable corrosion protection layer is applied to at least one side of the carrier film facing away from the damping compound. The adhesive element is made of aluminum, an aluminum alloy, stainless steel, or polyethylene terephthalate.

[0005] DE 10 2010 051 786 A1 discloses a method for the automated application of an adhesive element to a vehicle component, wherein an adhesive element is detached from a carrier element by means of several joining dies of a joining tool and then applied to the vehicle component. According to the invention, the carrier element with the adhesive elements is positioned on a support surface and fixed to the support surface by generating a vacuum between the support surface and the carrier element. Subsequently, an adhesive element is removed from the carrier element by means of the joining dies by generating a vacuum between the joining die and the adhesive element and applied to the vehicle component.

[0006] DE 10 2010 049 107 relates to an adhesive element consisting of a multilayered carrier layer and a self-adhesive damping compound, the damping compound being butyl rubber. According to the invention, the carrier layer is formed from a rigid material.

[0007] DE 195 22 272 relates to a laser vibrometer for vibration measurements, wherein, in order to achieve the necessary frequency shift, a modulation of the frequency of the laser radiation, preferably of the laser diode, takes place, and an interferometer arm, preferably the interferometer arm in the beam path to the measurement object, is significantly longer than the reference arm, in particular greater than 20 cm and up to approximately 100 cm.

[0008] From DE 10 2009 010 439 A1 a device for reducing oscillations and / or vibrations on flat components of vehicles is known, wherein the device comprises a carrier and a damping means provided on the carrier for reducing the oscillations and / or vibrations, wherein a plurality of damping means are provided on the carrier in order to detect a plurality of oscillation and / or vibration zones of the flat components.

[0009] The invention is based on the object of specifying a method for reducing the natural vibrations of a component and an insulating element for reducing the natural vibrations of a component.

[0010] With regard to the method, the object is achieved according to the invention by the features specified in claim 1 and with regard to the insulating element by the features specified in claim 6.

[0011] Advantageous embodiments of the invention are the subject of the subclaims.

[0012] In the method for reducing the natural vibrations of a component, the vibration behavior of the component is determined. At the positions determined in this way, where vibration amplitudes exceed a specified limit value occur, an insulating element is locally attached. This insulating element is designed as a multi-layer adhesive element with a carrier layer and a self-adhesive damping compound.

[0013] The local application of the insulation elements, designed as multi-layer, rigid adhesive elements known as adhesive pads, and their precise positioning result in a weight reduction compared to large, heavy, and comprehensive insulation mats, while simultaneously improving acoustic effectiveness. The resulting reduction in natural vibrations and increased structure-borne sound insulation results from the bonding of the multi-layer adhesive element to the component, creating a particularly rigid connection with high acoustic effectiveness. Using this method to reduce the natural vibrations of a vehicle component not only increases comfort for vehicle occupants, but also reduces fuel consumption due to the lower weight, thus reducing pollutant and carbon dioxide emissions.

[0014] Compared to existing large-area bitumen sound deadening foils, the structure-borne sound insulation can be reduced by 40%-60% while simultaneously reducing weight. Compared to the use of magnetic foils for structure-borne sound insulation, the weight savings are further improved. The effect of the structure-borne sound insulation is evident in the curves of transfer functions as a function of a third-octave center frequency, which are determined using laser scanning vibrometry.

[0015] Furthermore, the smaller size of the adhesive pads compared to large-area insulation mats and the localized or spot-like arrangement compared to a flat arrangement reduce material usage. This results in significant cost savings.

[0016] Furthermore, the adhesive pads are characterized by their very easy processing and attachment, especially on components with complex geometries. Automated processing of the adhesive pads is also possible, resulting in a reduction in production time and personnel requirements, resulting in further cost savings.

[0017] Embodiments of the invention are explained in more detail below with reference to drawings.

[0018] Showing: Fig. 1 schematically shows an insulating element according to the invention, Fig. 2A schematically shows a component with an insulating element according to the state of the art Fig. 2B schematically shows a sectional view of a component with an insulating element according to the prior art, Fig. 3 schematically shows a component with several applied insulation elements according to Fig. 1 and Fig. 4 schematically shows several insulation elements applied to a support element.

[0019] Corresponding parts are provided with the same reference numerals in all figures.

[0020] In Fig. 1 shows an insulating element 1 according to the invention. The insulating element 1 is designed as an adhesive element, which is formed from a multilayer carrier layer 1.1 and a self-adhesive damping compound 1.2.

[0021] Such an insulating element is known in principle from DE 10 2008 050 772 A1. However, there it is primarily used for a different purpose: to seal openings in a vehicle body.

[0022] In a particularly preferred embodiment, the carrier layer 1.1 is formed from a so-called 5xxx aluminum alloy, which has a magnesium content of 0.2% to 6.2%. The 5xxx aluminum alloy is characterized by high strength, which is in the range of 100 N / mm2 up to 450 N / mm 2 lies.

[0023] As an alternative to the 5xxx aluminum alloy, the carrier layer 1.1 is made of stainless steel, steel, or another rigid metal that also exhibits high strength. The carrier layer can also be made of a 4xxx, 5xxx, or 7xxx aluminum alloy, for example.

[0024] Due to this high strength, the insulating element 1 is particularly suitable for insulating structure-borne sound from components 2. Such a component is shown in more detail in Figure 2. At the same time, the insulating element 1 is suitable for closing openings in components 2, particularly in body components, and is particularly easy to apply to the components 2.

[0025] The material from which the carrier layer 1.1 is formed is further characterized by high corrosion resistance, so that corrosion of the insulation element 1 is avoided.

[0026] To further improve corrosion resistance, a corrosion protection layer 1.3 is applied to both sides of the carrier layer 1.1. The corrosion protection layer 1.3 is formed, in particular, from a paint or a film, with the paint preferably being applied to the carrier layer 1.1 as a so-called KTL replacement coating (KTL = cathodic dip coating).

[0027] Such cathodic dip-painting replacement coatings or cathodic dip-painting systems are special paints optimized for their subsequent application. They are based on polyurethane, epoxy, melamine, polyester, and / or a mixture of these. Lubricants are also preferably added to a top coat of the paint to ensure the subsequent elasticity or flexibility of the insulating element 1. This allows it to be adapted to the respective component in a preferred manner.

[0028] The corrosion protection layer 1.3 formed from the paint or film can preferably be applied to the carrier layer 1.1 in a coil coating process, which is also known as strip coating or continuous metal strip coating.

[0029] In particular, the corrosion protection layer 1.3 is made of polyethylene.

[0030] The corrosion protection layer 1.3 further improves the adhesion of the damping compound 1.2, which is made of butyl rubber, to the carrier layer 1.1. Furthermore, the corrosion protection layer 1.3 is paintable, allowing the insulation element 1 to be easily painted in the vehicle's color.

[0031] To further ensure adhesion of the corrosion protection layer 1.3 to the carrier layer 1.1, a bonding agent layer 1.4 is applied to both sides of the carrier layer 1.1. The bonding agent layer 1.4 is preferably chromium-free and is applied as a thin liquid film to both sides of the carrier layer 1.1. The bonding agent layer 1.4 is preferably made of Alodine. ® NR 1453 from Henkel. This adhesion promoter layer 1.4 is also characterized by the fact that it also provides corrosion protection for the carrier layer 1.1.

[0032] In a further embodiment of the insulating element 1, it is also possible for the carrier layer 1.1 to be formed from a plastic with a similarly high strength. Corrosion of the carrier layer 1.1 is thereby prevented, so that at least the corrosion protection layer 1.3 can be omitted. Advantageously, an adhesion promoter layer 1.4 is applied to at least one side of the plastic, thereby improving the adhesion of paint applied to the carrier layer 1.1. Thus, the insulating element 1 can be easily painted over and visually matched to the color of the component.

[0033] The illustrated multi-layer structure of the insulation element 1 with the carrier layer 1.1 made of the rigid material and the damping mass 1.2 made of butyl rubber is characterized by particularly good acoustic properties, so-called deadening properties, and simple and flexible processing.

[0034] The damping compound 1.2, made of butyl rubber, is characterized by its long-lasting application on metal sheets oiled with anti-corrosive oil. The insulating element 1 is also characterized by its chemical resistance to water, alcohols, diluted acids, and alkalis. The butyl rubber is primarily based on thermoplastic elastomers, polymers, adhesive resins, fillers, thixotropic agents, and other modifiers.

[0035] In order to avoid electrical conduction between the carrier layer 1.1 and the body component via the damping mass 1.2 and thus corrosion of the carrier layer 1.1 and / or the body element, the corrosion protection layer 1.3 introduced between the carrier layer 1.1 and the damping mass 1.2 is designed to be electrically insulating.

[0036] Alternatively or in addition to the introduction of the electrically insulating corrosion protection layer 1.3, a butyl rubber from which certain fillers, such as carbon black, have been removed can be used to reduce the electrical conductivity of the damping mass 3.

[0037] Fig. 2A shows a plan view of a component 2 which, according to the state of the art, is provided with an insulating element 1 in the form of a large-area insulating mat, which ensures the desired structure-borne sound insulation. Fig. Figure 2B shows a cross-sectional view of the component and insulation mat 1. The figures clearly show that this prior art insulation mat requires a large amount of material, which further increases the component weight.

[0038] In contrast, Fig. 3 shows the inventive solution in the form of a component 2 with several applied insulating elements 2. In the illustrated embodiment, the component 2 is a vehicle body component made of sheet metal. In alternative embodiments, the component is a component from other sectors, for example, from the construction industry, shipbuilding, aircraft construction, or household appliance manufacturing. The component 2 can also be made of steel sheet, aluminum sheet, cathodic dip-coated or paint-coated parts, or plastic parts.

[0039] Vibrations and noise can occur during operation of component 2. In the illustrated embodiment of component 2 as a body component of the vehicle, the vibrations and noise are generated by the operation of the vehicle at component 2. To minimize the vibrations and noise that occur, structure-borne noise from component 2 is attenuated by locally, i.e., spot-like, applying several insulation elements 1 to component 2.

[0040] For this purpose, the vibration behavior of component 2 is determined in a simulation.

[0041] In a particularly preferred embodiment, structure-borne sound investigations are carried out on the component 2 or on combinations of several components 2, such as vehicle bodies, by means of laser scanning vibrometry.

[0042] For this purpose, component 2 is firmly clamped at an upper edge in a manner not shown in detail and excited by an electrodynamic vibration exciter, also called a shaker. The frequency spectrum of the excitation typically covers a bandwidth of 40 Hertz to 1000 Hertz.

[0043] The vibrations generated by component 2 are recorded using a so-called laser scanning vibrometer (also not shown). For this purpose, a measurement grid with a large number of scan points is defined on component 2. Component 2 is initially excited with the vibrations while empty, i.e., without applied damping elements 1 or other damping materials. The distribution of the vibrations across component 2 is measured at various frequencies using the laser scanning vibrometer. A so-called color map is generated for each frequency, in which different vibration amplitudes are represented in different colors.

[0044] The vibration amplitudes are determined from the respective colors in the color map. Areas of component 2 with high vibration amplitudes are distinguished by their color from the remaining areas.

[0045] At these positions, where the vibration amplitudes exceed a specified limit value, an insulating element 1 is attached to locally stiffen the component 2.

[0046] The insulating element 1 is glued to the component 2 using the damping compound 1.2, thus securing it. The insulating element 1 can be positioned at positions on the component 2 that are made of solid material or at positions where there are openings in the component 2. The insulating element 1 is simultaneously used to close openings in the component 2.

[0047] In a further development, the effectiveness of the insulation elements 1 arranged on the component 2 is verified by repeating the measurement using laser scanning vibrometry and evaluating the generated color maps. Depending on the results, the effectiveness of the insulation elements 1 is optimized by making corrections if necessary. The corrections are made, in particular, by arranging insulation elements 1 of a different size, correcting the position of the applied insulation elements 1, and / or arranging additional insulation elements 1.

[0048] The acoustic effect of the insulation element 1 is adjusted by several parameters: on the one hand, it is determined by the elasticity (the Young's modulus), the thickness, the density and the basis weight of the damping mass 1.2 and, on the other hand, by the thickness, the basis weight and the stiffness of the carrier layer 1.1.

[0049] In order to achieve particularly good structure-borne sound insulation, the carrier layer 1.1 according to the invention preferably has a thickness of 0.1 mm to 0.4 mm.

[0050] The sandwich-like structure of the insulation elements 1, combined with the bonding of the insulation element 1 to the component 2, results in a high local area moment of inertia. This results in a very significant stiffening of the component 2 and thus improved structure-borne sound insulation and sound deadening. The sound deadening effect is greater the stiffer the material used for the carrier layer 1.1.

[0051] In particular, insulation elements 1, whose carrier layer is made of aluminum and whose damping layer 1.2 is made of butyl rubber, demonstrate very good sound deadening properties. This means that surface vibrations of component 2 are significantly dampened, thus reducing structure-borne sound and preventing the radiation of airborne sound.

[0052] In order to ensure that, despite the high rigidity of the insulating element 1, an optimized attachment of the insulating element 1 to the contours of the component 2 can be achieved, the insulating elements 1 are manufactured in different sizes and shapes so that, according to the invention, an area of the component 2 with a high vibration amplitude can be stiffened with a precisely fitting insulating element 1 or several insulating elements 1.

[0053] The application of the insulation elements 1 to the component 1 is carried out manually by arranging one or more insulation elements 1 at the position with high vibration amplitude detected by the laser scanning vibrometry.

[0054] The use of the carrier layer 1.1 formed from the rigid material results in a particularly advantageous way in that the insulation elements 1 can alternatively or additionally be applied to the component 2 in an automated manner.

[0055] As in Fig. 4, the insulation element 1 is automatically separated from a support element 3, for example by means of a robot, and then automatically attached to the component 2. The insulation elements 1 can be applied both for structure-borne sound insulation of the component 2 and for tightly sealing openings in the component 2.

[0056] Such a support element 3 with several insulation elements 1 arranged on it is shown in Fig. 4 shown.

[0057] The carrier element 3, the so-called liner, is designed as a prefabricated flat sheet onto which several insulation elements 1 are applied. The carrier element 3 is made of paper, polyethylene, or polyethylene terephthalate film.

[0058] According to the invention, all variants of insulation elements 1 required for a specific application, for example a vehicle, are arranged as a set, in particular on one sheet or on several sheets. The design of the carrier element 3 as a flat sheet enables the variety of insulation elements 1 to be managed for a specific application while minimizing material waste and space consumption. Compared to the use of insulation elements 1 applied on rolls, there is also the advantage that uncontrolled detachment of the insulation elements 1 from the carrier element is avoided. Furthermore, material waste due to production can only be sorted out with sheet material. With roll or continuous material, however, malfunctions can occur in an application system for the automatic application of the insulation elements 1.

Claims

[1] Method for reducing the natural vibrations of a component (2), characterized by that a vibration behavior of the component (2) is determined and that at determined positions with vibration amplitudes which exceed a predetermined limit value, an insulating element (1) is locally fastened, which is designed as a multi-layer adhesive element with a carrier layer (1.1) and a self-adhesive damping mass (1.2) and that an area of the component (2) with a high vibration amplitude is stiffened with a precisely fitting insulating element or several insulating elements. [2] Method according to claim 1, characterized by that the vibration behavior is determined in a simulation. [3] Method according to claim 1 or 2, characterized by that the vibration behavior is determined using laser scanning vibrometry. [4] Method according to one of the preceding claims, characterized bythat the insulation element (1) is attached to the component (2) manually and / or automatically. [5] Method according to one of the preceding claims, characterized by that the insulation element (1) is automatically separated from a support element (3) and fastened to the component (2). [6] Insulating element (1) for reducing the natural vibrations of a component (2), characterized bythat the insulating element (1) is formed as a multi-layer adhesive element from a carrier layer (1.1) and a self-adhesive damping compound (1.2), wherein the carrier layer (1.1) with a thickness of 0.1 mm to 0.4 mm is made of a rigid material and the damping compound (1.2) is made of butyl rubber, wherein in order to avoid uncontrolled detachment, to sort out production-related material waste, to avoid malfunctions in an application system and to control a variety of variants of the insulating elements for a specific application, all required variants of insulating elements are arranged as a set on one sheet or several sheets. [7] Insulating element (1) according to claim 6, characterized by that the material is a naturally hard aluminum alloy or stainless steel. [8] Insulating element (1) according to claim 7, characterized by that the naturally hard aluminum alloy is a 5xxx aluminum alloy.

Images