DE9422122U1 - Vibration-damped component - Google Patents

Description

Volkswagen AG UmfoTEC

38436 Wolfsburg Forming Technology GmbH

PO Box 16 46
37146 Northeim
K5658

Vibration-damped component

The invention relates to a vibration-damped component according to the preamble of the main claim, whereby a knitted fabric is understood to mean a loop-forming knitted fabric.

There are a number of structural components that tend to emit secondary air noise due to external excitation and/or their natural resonance behavior. Pipe trickling, whirring noises and flow rattling are undesirable in pipes. Thin-walled shielding plates (e.g. on exhaust systems of internal combustion engines) or cladding can be just as susceptible to vibration as lightly dimensioned structural components that are driven by a motor during operation, e.g. steel wheels (rims).

From the generic DE 38 12 820 A1, a vibration-damped component is known, for example in the form of a silent block, with at least one support made of a friction-absorbing knitted fabric, which in turn is made up of several elastically tensioned knitted layers.

From the book "Guide to Technical Mechanics", Göldner/Holzweissig, Dr. Dietrich Steinkopff Verlag Darmstadt 1976, pages 592 to 593, it is generally known how to select the mass and spring stiffness of a damper for the purpose of a damping effect.

Vibration-damped components in the form of thin-walled

Corrugated pipes, such as those used in exhaust systems of motor vehicle internal combustion engines

can be used, with coating-like single-layer metal mesh fabrics as

Supports that extend practically over the entire length of the respective metal pipe

The desired vibration damping is to be achieved through friction between the support and the mesh of the same (“internal” friction). However, the disadvantage is the difficulty of setting and maintaining defined contact and thus friction conditions, especially as the shape of the bag changes during installation and operation.

can occur. In addition, the support extends practically over the entire length of the pipe and can impair the desired properties of the pipe, such as flexibility and heat exchange with the environment during operation. Furthermore, the application of the known supports to structural parts with complex shapes is difficult. Finally, a fundamental disadvantage of this state of the art is the limitation to vibration absorption through friction damping.

The invention is based on the object of creating a generic vibration-damped component with high, defined vibration absorption that can be adapted to the respective application and is insensitive to operation, which is easy to install and whose at least one support is largely independent of the special shape of the respective structural part.

The solution to this problem according to the invention consists in a generic component with the characterizing features of the main claim, advantageous designs and applications are described in the subclaims. The invention therefore includes a tuned vibration damper with internal friction that is concentrated at the location of the vibration maximum.

Because the respective support in the invention only extends over the area of the vibration maximum (vibration antinode), the disadvantages of the discussed prior art are avoided without having to accept disturbing impairments of the acoustic damping. The dimensioning of the support serves to achieve additional defined vibration absorption by cancellation using the mass and elasticity of the knitted fabric.

The drawing shows three embodiments of the invention, partly in section. While Fig. 1 refers to an exhaust pipe as a structural part susceptible to vibrations

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Fig. 2 deals with the case of a thin panel that is susceptible to vibration. Finally, Fig. 3 shows a wheel that is susceptible to vibration.

If we first look at Fig. 1, only a short length of the exhaust pipe 1, the course of which is not of interest in the context of the invention, is shown in the area of a maximum of a disturbing vibration, which is caused by the operation of a connected internal combustion engine and/or vibrations when driving a vehicle equipped with it. The exhaust pipe 1 carries the support 2, which extends lengthwise only over the area of the vibration maximum and is made of multi-layered wire mesh, which surrounds the pipe 1 in a ring-like manner and transmits vibrations. For this purpose, it can be shrunk onto it. If necessary, in addition to this measure, the support 2 is braced by a defined amount both within itself and against the line 1 by means of the housing 5, which is made up of two half shells 3 and 4 to facilitate assembly and is open in the direction of the line 1, so that together with the choice of material and dimensions of the support 2, defined properties with regard to friction and absorption are obtained.

Instead of a housing, the support 2 can also be fixed by a hold-down device, just by shrinking or in another way.

At this point it should be added that instead of a knitted fabric made of metal wire, one made of sufficiently elastic plastic fibers can also be used, which interlock to form a loop.

While in Fig. 1 an annular support is used as a combined vibration absorber and damper, Fig. 2 shows a top view of a cushion-like support 20 on an essentially flat covering sheet 21. Here too, the support, which is again formed by a wire mesh of several layers, only extends over the area of a vibration maximum.

Finally, in Fig. 3, a floating rotating wheel 30 carries supports 31 in the area of vibration maxima.

Common to all versions are high acoustic effectiveness, easy tuning, ease of installation, low storage requirements and low effort to achieve vibration damping and cancellation.

Claims (10)

K 5658/1770-kü-hi CLAIMS 1. Vibration-damped component with at least one support made of a friction-vibration-absorbing knitted fabric, containing several elastically tensioned knitted fabric layers, on a structural part at risk of vibration, characterized in that that the support (2) extends on the structural part (1) only over the area of a vibration maximum and its dimensions and its ratio of mass to spring constant are selected with a view to additional vibration absorption through vibration damping. 2. Component according to claim 1,
characterized, that the support (2) contains frictionally pressed metal mesh. 3. Component according to claim 1 or 2,
characterized, that the support (2) is held in vibration-transmitting contact with the structural part (1) by means of a housing (5) open in the direction of the structural part (1). 4. Component according to one of claims 1 to 3,
characterized, that the support (2) in the case of a rod-, tube- or hose-like construction part (1) is designed to enclose it in a ring-like manner. 5. Component according to claim 4,
characterized, that the support (2) is shrunk onto the structural part (1). 6. Component according to one of claims 1 to 3, characterized in that the support (20) is designed in a cushion-like manner in a structural part (21) which is flat at least in the region of the vibration maximum. 7. Part according to claim 4 or 5, characterized in that the structural part (1) is a component of an exhaust system. 8. Bag according to claim 6, characterized in that the structural part (21) is a thin-walled cladding and/or shielding. 9. Component according to one of claims 1 to 8, characterized in that the structural part (30) is driven during operation. 10. Component according to claim 9, characterized in that the structural part is a wheel (30), in particular a rim.