RU2188772C2 - Multilayer noise-damping lining of vehicle body panel - Google Patents

Abstract

FIELD: transport engineering; passenger cars. SUBSTANCE: proposed multiplayer noise-damping lining has at least layer 1 made of porous noise-absorbing material on outer surface of which film thin protective layer 3 is placed by means of adhesive layer 2, and on mounting side, adhesive layer 4 is found on which easy-to-remove layer 5 of protective material is placed. Adhesive layer 2 between outer side of porous noise-absorbing material 1 and opposite surface of film protective layer 3 is made in form pattern of great number of regular geometric figures formed by thin lines. Lines of pattern can intersect forming great number of elementary closed geometric figures with space (lining) 8 between layers 1 and 3. Lines of patterns can be made relatively parallel or equidistant. Simultaneously, lines of pattern can have solid trajectory or made in form of interrupted dashes. EFFECT: improved acoustic comfort in cab (car interior), reduced noise. 5 cl, 11 dwg

Description

 The invention relates to transport engineering, namely to noise-damping gaskets (SHVD), which are mounted inside or outside the cabin panels, on the elements of the cabin (passenger compartment), and / or the walls of the engine compartment of cars and trucks, tractors, buses and other land vehicles.

 The operation of the above vehicles with the implementation of work processes in their power plants, auxiliary units and systems is accompanied, as a rule, by increased noise emitted both outside - into the environment and into the cabin (passenger compartment), which has an irritating effect on a person, accelerates the process of fatigue, weakens attention and significantly weakens mental reactions. The negative impact on the driver (passengers) is the greater, the higher the noise level in the cabin (cabin) and the longer its exposure, which, ultimately, is directly related to the safe operation of these vehicles. Radiating outward from the engine compartment into the environment, noise is one of the serious sources of environmental pollution, adversely affecting public health in residential areas.

 Strong vibrational and acoustic excitation of the metal structure of individual body panels, which form, in particular, the passenger compartment of a passenger car, for example, the front panel of the engine compartment, the front mudguards of the front wings, the walls of the air intake duct of the air conditioning system, the front floor of the body, etc., due to the good vibration conductivity of the metal, it is easily transmitted to the interior space from the structures of the front panel, floor, sidewalls, doors, hood, mudguards, etc., which, in turn, are also loaded with other vibrators conductive mechanisms and systems of the car - the tires, suspension elements of the vehicle and the power unit, transmission nodes, sound emitters heads audio systems, etc. associated with the various rigid body and elastic communication links. Thus, thin-sheet panels, which directly form the space of the cabin (passenger compartment) and engine compartment, are direct structural emitters of acoustic (noise) energy directly into the air volume of the cabin, forming an unfavorable acoustic climate in the form of increased internal noise in the cabin. On the other hand, in the space of the engine compartment and in the passenger compartment (cabin), it is desirable to effectively absorb airborne sound (transmitted by air) emitted by the engine, engine systems, diffusers of loudspeakers (heads) of audio systems, etc.

 In the practice of automotive industry, in order to reduce the negative acoustic and vibration effects on humans, various kinds of multilayer noise vibration damping pads, as a rule, with a high degree of adhesion (due to the adhesive or thermal adhesive layer they have), are mounted on the surface of the corresponding body panels, and depending from the functions primarily performed by them (vibration damping, sound absorption or sound reflection) have a corresponding composite structure. For example, multifunctional gasket has been widely used, which is made in the form of a multilayer “sandwich”, including an external thin protective sound-transparent layer (for example, thin aluminum foil), an adhesive (adhesive or thermo-adhesive) layer, and a soft porous (foam or fibrous) sound-absorbing layer, for example open-cell polyurethane foam - polyurethane foam, then a heavy (weight) layer of a viscoelastic vibration damping material (for example, based on bitumen mastic) and a mounting layer of adhesion (sticky substance), medium the product of which the gasket is mounted on the defatted surface of the corresponding body panel. In the pre-installation or storage state at the warehouse, the adhesion assembly layer is protected by an easily removable, usually wax, coating that is dismantled immediately before the gasket is installed. In more detail, the design features of such gaskets and their functional purpose are described below.

 Known noise insulation coating described in the copyright certificate of the USSR 1678668, MKI B 60 R 13/08, publ. 09/23/91, BI 35, which is effective for its intended purpose, but has limited use and has significant thickness and low mechanical strength, because during operation, when pressure is exerted on the surface of the feet of the driver or passengers, its structure, changing its density, degrades noise-damping qualities or even collapses. It should be noted that a specific feature of such panels is limited efficiency due to the limitation of their maximum thickness, since at large thicknesses, favorable for increasing sound absorption and sound insulation, the useful volume of the cabin (passenger compartment) is significantly reduced and the cost of coverage increases.

 Known sound-absorbing (ZP), sound-insulating (ZI) gasket for the front end flap and adjacent mudguards of the front wings of the car body, described in Japanese application 2-32172, MKI B 60 R 13/08, publ. 07/18/90, BI 2-805. In this case, we are talking about the RFP, the ZI gasket installed in the area of the front flap, the front floor of the body and the mudguards of the front wings of the body, the distinguishing feature of which is to give a local seal to this panel in the area of influence (contact) of the legs of the driver and passenger, as well as the use of improved adhesion of this zone with a fully formed noise insulating (SHI) panel, which to a certain extent (mainly due to the provision of sufficient adhesion) provides the effect of vibration damping (VD). In this case, the effect of some VD arises in the process of bending microdeformations of the structure of a whole-formed SI gasket, accompanied by dry friction of its fibers, or a foamy skeleton of a gasket with weak scattering and conversion to thermal energy. Basically, the acoustic effect of using said gasket arises from its sound-absorbing and sound-insulating effect.

 When installing a sound-absorbing pad, if necessary measures are not provided, the structure of its material (layers) undergoes microdeformations caused by compressive or tensile deformation forces, which can, on the one hand, lead to mechanical destruction of the pad and, on the other hand, degrade the functional qualities of the pad because under the influence of tensile forces, first of all, the external protective and the external zone of the sound-absorbing porous layer conjugated with it becomes more rigid (stretched or compressed), dense and partially lose the sound transparency function, tightening the adjacent structure zones of the sound-absorbing foam (fibrous) layer, due to which the porous layer is noticeably weaker performs the function of sound absorption.

 To a large extent, the problems described above were eliminated in the design of the gasket of the noise-reducing panel of the vehicle body, described in the utility model of the Russian Federation 11519, class. B 60 R 13/08, publ. RU PMPO from 10.16.99, which allows to improve acoustic comfort in the cab (passenger compartment) of a vehicle by increasing the efficiency of sound-absorbing characteristics of ballscrew installed on the body panel, while simplifying the installation of ballscrew and ensuring the possibility of placing the high-speed rail in a large area and, in features on curved surfaces of body panels of any size and configuration. The known design of a noise reducing gasket for a vehicle body panel comprises a multilayer coating, the structure of which includes at least a layer of an external protective sound-transparent material such as a thin film (foil), an adhesive layer connecting the film with a porous sound-absorbing layer, a layer of porous (foamy or fibrous) sound-absorbing material and a mounting layer of adhesive material on which an easily removable protective coating is mounted (for example, a layer of waxed paper), In said structure, from its front surface, towards the adhesive layer, blind "unloading" cuts of a certain depth are made.

 With this design, the mechanism of suppressing structural and airborne noise caused by the vibrating elements of the body panels and the diffuse sound falling on the panel in the air cavity of the cab is activated to a large extent, since the introduction of the mentioned blind cuts into the gasket structure avoids additional tension and increases the rigidity and density of the outer layers gasket structure (film and porous layer), and also allows you to tightly and better mount the gasket to the appropriate the guide bar body at its non-planar geometric shape by increasing the dynamic compliance and ductility of the panel as a whole.

 The prototype considered has the following disadvantages.

 The presence of blind cuts in the porous polyurethane foam layer and the cut of the outer facing protective layer of the gasket structure cause the inevitable ingress of moisture and its absorption by the open-cell sound-absorbing polyurethane foam layer, which subsequently significantly worsens the operational (corrosion, damage during freezing) and acoustic characteristics of the material (decrease in sound absorption coefficient). Sticking gaskets on the convex (non-planar) surfaces of body panels significantly affects the aesthetic characteristics of the panel (the appearance of significant gaps in the areas of blind cuts).

 The essence of the invention lies in the fact that in the well-known multilayer noise-reducing gasket of a vehicle body panel, for example a passenger car, containing at least a layer of porous sound-absorbing material, on the outside of which a thin protective layer of film material is adhesively mounted, and on the mounting side, an assembly adhesive layer on which an easily removable layer of protective material is placed, an adhesion layer between the outer side of the porous sound-absorbing material and the counter NOSTA protective layer film material is formed as a thin line pattern composed of a plurality of regular geometric shapes. The pattern lines can intersect with each other, forming many elementary closed geometric shapes, or the pattern lines can be made mutually parallel or equidistant. At the same time, the lines of the pattern can have a continuous path or be made in the form of discontinuous lines.

Thus, in the proposed multilayer panel instead of blind cuts (which takes place in the prototype) it is proposed:
- without violating the integrity and tightness of the outer surface of the panel as a whole, ensure the minimum negative effect of the adhesive layer on the outer surface of the PUF - layer, thereby preserving the named outer surface of the PUF as a flexible and porous, not covered by an adhesive layer (not fused by thermo-adhesive effect) having air contact with a protective layer of film (foil) material, which greatly increases the effect of sound absorption;
- increases the reliability and durability of the panel, its aesthetic qualities.

The invention is illustrated in the drawings, where:
- figure 1 shows a multilayer noise reduction panel;
- figure 2 ... 4 shows the solid lines of the pattern intersecting each other and forming a set of elementary closed cavities, along which an adhesive layer is applied;
- figure 5 shows the solid lines of the pattern made mutually parallel, along which the adhesive layer is applied;
- figure 6 shows a panel in which the lines of the pattern are made in the form of discontinuous lines;
- Fig.7 shows a diagram of the installation of multi-layer noise-reducing gaskets on the hood panel, mud flaps and screens of the engine compartment of a VAZ 21214-40 Niva car;
- in FIG. Figure 8 shows 1/3 octave noise spectra characterizing the effect of reducing the external noise of a VAZ-21214-40 Niva car from the use of a set of sound-absorbing parts with improved sound-absorbing properties compared to a set without sound-absorbing parts. (Test method - GOST 27436-87, UNECE Regulation 51-02);
- Fig.9 shows curves characterizing the effect of changing the normal coefficient of sound absorption from the method of changing the crosslinking of the protective film with porous sound-absorbing material (measured by the method of acoustic interferometer);
- figure 10 shows the curves characterizing the effect of changing the reverberation coefficient of sound absorption from the method of changing the crosslinking of the protective film with porous sound-absorbing material (measured by the chamber method);
- in FIG. 11 shows changes in the reverberation coefficient of sound absorption of full-scale parts of the gaskets of the hood of a VAZ 21214-40 Niva car (measured by the chamber method).

 The proposed multilayer noise-reducing gasket for a vehicle body panel, for example a passenger car, contains at least layer 1 of porous sound-absorbing material, on the outside of which adhesive 2 is mounted a thin protective layer 3 of film material, and on the mounting side there is a mounting adhesive layer 4, on which is placed easily removable layer 5 of the protective material. The adhesion layer 2, between the outer side of the porous sound-absorbing material 1 and the opposing surface of the protective layer of the film material 3, is made in the form of a set of fine geometric shapes made up of thin lines 6. The pattern lines can intersect each other, forming many elementary closed geometric shapes, moreover between the layers 1 and 3, a thin air cavity (air layer) 8 is formed, or the pattern lines can be made mutually parallel or equidistant. At the same time, the lines of the pattern can have a continuous path or be made in the form of discontinuous lines.

 An example of a specific application of the proposed multilayer panels is shown in Fig. 8. Here are shown: the steel panel of the hood 11, the proposed multilayer gaskets of the hood 12, the steel panels of the mudguards and screens 13 and the multilayer noise-reducing gaskets 14 mounted on them.

 The specific composition of the structure of the gasket depends on the degree of sufficient effectiveness of the functions it performs, and in the general case, the gasket can take the form of a multilayer sandwich, including, in particular (when viewed from the front surface) - a thin soundproof layer 3 (polyester, vinyl, urethane, polyethylene film, aluminum foil, etc.), adhesion layer 2, porous (foamy or fibrous) layer 1 of sound-absorbing material, adhesion layer 4 and a protective layer (most often made of thick waxed paper) layer 5, which is easily removable It is removed from the gasket before it is directly mounted on the degreased surface of the corresponding body panel.

 Before directly installing the gaskets on the corresponding body panel, for example 11, 13, the protective paper layer 5 is removed and, by applying the gasket with the adhesive layer 4 on the degreased surface of the panel, fix it on the steel body panel in the right place (by pressing manually or using a magnetic roller).

 Often technical problems arise when the body panel on which the gasket is mounted has a pronounced complex spatial geometric shape, for example, rounded, concave, convex or curved with a small radius, etc. In this case, the structure of known, traditionally used panels when installing the latter on such a body panel is subjected to significant static tensile or compressive forces, resulting in increased rigidity of the gasket structure and especially its surface layer, and this, as experiments show, significantly and negatively affects on its sound-absorbing and vibration-damping qualities and does not always ensure a high-quality fit of mating surfaces due to the relative stiffness of the puncture ki and limited adhesiveness of the adhesive layer.

 The proposed multilayer panels have the advantage that the adhesive contact of the protective layer 3 of the film material with the opposing compliant porous surface of the sound-absorbing layer 1 is carried out along a very limited interface surface along thin lines 6, i.e. the overwhelming surface area of layer 1 is not covered by the adhesive, but remains porous and pliable, in contact with layer 3 through the air gap 8, which avoids tension and increases the stiffness and density of the outer layer of the PU foam structure (including due to non-filling of the structure with glue) , to exclude “clogging” of the entire porous surface of the polyurethane foam layer with adhesive or thermo-adhesive reflow, further improving the sound absorption effect also due to the membrane sound-absorbing effect of the protective film 3. Simultaneous enno with this free surface of the adhesive layer 1 feedback is easily deformed and thus is not exposed to mechanical damage, and in comparison with the prototype -. and the negative influence of moisture, dust, etc., thus maintaining stable characteristics of sound absorption.

 The implementation of the adhesive 3 patterns in the form of regular geometric shapes 7 contributes to a uniform distribution of power stresses on the surface of the panel. The presence of elementary closed cavities between layers 3 and 1 (the presence of air gaps) makes it possible, during micro-deformation of the panel to bend, to partially compensate for the deformable part of the material of the panel 3 into these closed cavities 8.

 A big advantage is that with this design significantly (many times) saves the expensive adhesive used for adhesion of the protective layer 1 with the surface of the sound-absorbing layer 3 (in comparison with the continuous application of the adhesive layer over the entire surface, which takes place in the prototype) .

 The effectiveness of the proposed technical solution is confirmed by the results of laboratory and bench tests of samples of materials and full-scale full-scale samples of parts made using the claimed materials, as well as the results of road tests of VAZ cars, see FIG. 9 ... 12. As follows from the above results, the use of a non-prototype method of bonding (stitching) sound-translucent aluminized polyester film 3 with a thickness of 0.012 mm to the surface of a sheet of open-cell acoustic polyurethane (layer 1) 25 mm thick allows, in comparison with the known use of a continuous adhesive layer, to increase the normal coefficient sound absorption (measurements in a setup such as an acoustic interferometer "Kundt Tube") in a wide frequency range up to 26%, increase the reverberation coefficient of sound opogloscheniya (measurements in a small chamber reverbetsionnoy type "Cab Alpha") up to 40%. The use of a set of noise-absorbing parts made of the claimed material, see figure 1, made it possible to ensure high values of the reverberation coefficient of sound absorption in the frequency range 1000 ... 8000 Hz, see figure 12, i.e. in the range that mainly forms the external noise of the car. The use of this set of parts on a VAZ-21214-40 Niva car made it possible to effectively reduce the general levels of external noise of the car in accordance with national standards (GOST 27436-87) and international (UNECE Regulation No. 51-02) 2 ... 3 dBA due to the absorption of medium and high frequency sound energy 315 ... 8000 Hz up to 5 dB, see Fig.9.

Claims (5)

 1. A multilayer noise-reducing gasket for a vehicle body panel, for example, for a passenger car, containing at least a layer of porous sound-absorbing material, on the outside of which a thin protective layer of film material is adhesively mounted, and on the mounting side there is an assembly adhesive layer on which an easily removable layer of protective material, characterized in that the adhesion layer between the outer side of the porous sound-absorbing material and the counter surface of the protective layer of the film About the material is made in the form of a set of thin lines of a set of regular geometric shapes.  2. The gasket according to claim 1, characterized in that the lines of the pattern intersect each other, forming a set of elementary closed geometric figures, while a closed air cavity is formed between the inner side of the protective layer and the outer side of the porous sound-absorbing material of each of the elementary geometric figures.  3. The gasket according to claim 1, characterized in that the pattern lines are mutually parallel and / or equidistant.  4. Gasket according to any one of paragraphs. 1-3, characterized in that the lines of the pattern are solid.  5. The gasket according to any one of paragraphs. 1-3, characterized in that the lines of the pattern are made in the form of discontinuous lines.

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