Dr. Alois Stankiewicz Gmbh

Dr. Alois Stankiewica Gmbh

Heinemann Gahlau

Manfred Hoffmann

Klaus Wittenmayer

Christoph Kittel

Ehrenfried Blumel

Thomas Stankiewicz

Norbert Seemann

Herbert Baumeister

Manfred Laubner

Viscoelastic plastics materials having a dynamic elasticity modulus of 10.sup.7 to 10.sup.10 Nm.sup.-2 and a loss factor of at least 5 are used for the manufacture of motor vehicle parts, such as wheel housing parts, instrument panels, and door panels, in order to reduce interior noise.

Interior noise reduction in motor vehicles

The invention relates to an adhesive insulating system that is non-destructively removable, e.g. for the purpose of repair, for sound insulation of partition walls, particularly in motor vehicles. To overcome the disadvantages associated with the previous systems in mounting and also in repair a layer of material of a highly under-cross-linked polyurethane is now applied between the substrate and the overlying layers. This polyurethane layer has, owing to its under-cross-linking, a great adhesive effect and thus enables the substrate and the insulating layers to be joined in a force-locked manner. The adhesive material layer can be prefabricated or is prepared by spraying on a highly under-cross-linked 2-component mixture of the polyurethane former.

Adhesive insulation system

A sound insulation part for surfaces with known source-sink distribution, in particular in passenger spaces of motor vehicles, is provided, which is designed as a mass-spring system with discontinuities incorporated therein for the purpose of converting sources into sinks. In order to achieve a particularly effective sound insulation with low mass or light weight, the sound insulation part contains, over limited parts of its surface, closed cells (1) embedded in the spring (foam 3) and encased in coils (2). These cells (1) can be directed towards the heavy layer (4) or the panel (8) which the part adjoins, or can be wholly or partly in the intermediate region. The cells (1) can be gas- or air-filled. The foils (2) advantageously have masses of about 25 to 150 g/m.sup.2 of surface.

Sound insulation part for surfaces

A partition (4) for separating the engine compartment (2) from the passenger compartment (3) of a motor vehicle comprises a wall (5) and a covering (6) of noise-insulating material on the engine compartment side of the wall. The partition (4) has convex or concave deformations (8, 9, 11) in one or several areas of the high noise occurrence.

Motor vehicle noise insulation

In order to subject sound-emitting surfaces of motor vehicles to localized interference with the sound field, for example, sound obstruction and attenuation, it is already known to insulate the region of the sound sources against noise by cladding the passenger space from within at the relevant point of the wall to be insulated by application of a heavy layer and of a resilient layer which, if necessary, is impregnated with a sound-attenuating material. However, limits are imposed on a sound-insulating cladding of this kind even when further sound-reducing materials are applied, as the transmission of sound energy to the interior space of the motor vehicle then takes place in other ways. In order to remedy this, at least one sound sink is subjected to intensified sound absorption by providing on the wall (2,3) a sound-insulating cladding (6/7). Specifically this cladding comprises a resilient layer (6) preferably made of foam material or fleece which is covered by a heavy layer (7).

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Celle, Germany

Heinemann Gahlau