Uncoupling element for uncoupling vibrations

Details Uncoupling element for uncoupling vibrations Uncoupling element for uncoupling vibrations

2000-02-04

2001-12-04

Denion, Thomas (Department: 3748)

Power plants

Internal combustion engine with treatment or handling of...

Having vibration attenuating, or expansion and contraction...

C060S323000, C138S109000, C138S121000, C285S300000, C285S049000

Reexamination Certificate

active

06324837

ABSTRACT:

BACKGROUND OF THE INVENTION
The invention relates to an uncoupling element for uncoupling vibrations in an exhaust gas conduit of an internal combustion engine, having a screw thread-shaped or annular waved, metallic corrugated hose, which is installed between a first conduit element arranged upstream and a second conduit element arranged downstream.
With exhaust gas conduits of motor vehicles, it is known to install a flexible conduit element in the form of waved, corrugated hose as an intermediate part, in order to absorb motions and vibrations and to uncouple transmission to adjacent components. Such motions and vibrations result on the part of the elastically mounted drive mechanism as a consequence of load shifting reactions in normal driving operation or also as temperature-conditioned changes in length within the exhaust gas conduit. Transmission of these motions and vibrations to the vehicle should be prevented as far as possible, in order to increase the lifetime of the exhaust gas facility and to prevent undesirable transmission of body noise, as well as the emission of air noise.
An example of such a flexible conduit element for exhaust gas conduits of motor vehicles may be taken from German utility model DE 296 09 293 U1. The conduit element described there is firmly connected with the conduit elements lying upstream and downstream, usually by means of a welding connection. For bracing in the axial direction, the corrugated hose is enclosed by a knit hose fastened on both ends of the corrugated hose. In the cited utility model, it is moreover proposed to additionally enclose the knit hose with a netting hose.
Such a known uncoupling element is indeed gas-tight and internally stable, but the installation of this conduit element in the exhaust gas facility by the motor vehicle manufacturer must be conducted very carefully. Fastening of the connection ends of the corrugated hose may be undertaken only within narrow tolerances. Even the replacement of a corrugated hose, which has possibly become harmful, requires exact processing by the workshop entrusted with it, as well as good capabilities in metalworking.
As an alternative to permanent installation of a conduit element just mentioned, it is known according to the prior art, for example from German published patent application DE 35 42 684 A1, to separably connect the exhaust manifold of a motor vehicle engine with a following corrugated hose. In this publication, the connection is undertaken by means of a sealing ring of slightly pre-stressed material, such as metal wires or metal shavings, which is arranged on the cylindrical running-out tube end and on which a bent collar of the corrugated hose is laid, wherein a profile clamp braces the collar together with the sealing ring on the tube end. It has become apparent though, that the uncoupling action of such a separable construction is capable of improvement. Also, a corrugated hose with good uncoupling action can hardly be joined in this manner with the tube end of a conduit element of an exhaust gas facility close to the engine.
SUMMARY OF THE INVENTION
Underlying the present invention is therefore the object of proposing an uncoupling element for uncoupling vibrations in an exhaust gas conduit of an internal combustion engine having a screw thread-shaped or annular waved metal corrugated hose, which combines a good uncoupling action with easy installation and repair friendliness.
In accordance with the invention, an uncoupling element of the type mentioned at the beginning is configured such that the first conduit element, arranged upstream in the region of its end to be connected with the corrugated hose, is provided with an annular bulge, that the first conduit element, downstream of the annular bulge, continues into a flame pipe which reaches into the corrugated hose without touching the inner waves of the corrugated hose, that in the transition region between the annular bulge and the flame pipe a centering surface is provided, and that the corrugated hose is separably connected with the first conduit element on the annular bulge by means of a clamp connection, while it lies against the centering surface.
The annular bulge on the first conduit element makes possible a very easy installation of the uncoupling element, wherein the fitter need not pay attention to the exact position of the clamp connection, since this is pre-determined by the annular bulge, and also ensures later an easy separability for repair purposes.
Downstream of the annular bulge, the first conduit element continues into a flame pipe which reaches into the corrugated hose and to this extent serves as a heat shield for the corrugated hose and, since the wave form of the corrugated hose could lead to flow disturbances, serves for better flow guidance. Moreover, the flame pipe has an external diameter dimensioned such that it does not touch the interior waves of the of the corrugated hose, and indeed not even when angular motions occur, owing to relative motions within the exhaust gas facility. After the flame pipe is constructed as a continuation of the first conduit element arranged upstream, its position relative to the first conduit element is unalterable, so that the corrugated hose can simply be put on over the flame pipe and fastened on the clamp connection. Moreover, the centering surface provided in accordance with the invention guarantees therein, in any case, an exact and nonetheless easy installation, wherein the spacing between the flame pipe and the internal waves of the corrugated hose, necessary for avoiding rattling noises, can be automatically maintained.
The centering surface finally forces, in interaction with the annular bulge, a centering of the corrugated hose relative to the first conduit element in all three spatial directions. Errors owing to inexact processing in the installation are thus largely ruled out per se.
Preferably, the flame pipe is formed in one piece on the first conduit element, wherein, as a rule, it will have an outer radius diminished in relation to the first conduit element.
The clamp connection of the corrugated hose on the first conduit element can be undertaken in usual manner by means of an installable profile clamp adapted to the annular bulge. Expediently, the annular bulge is here constructed as a V-shaped rim and the profile clamp as a V-shaped clamp. The clamp connection can then be made gas-tight in a simple manner, in that the corrugated hose is provided on its end facing the first conduit element with an annular flanged, outwardly conical-shaped collar, wherein the annular bulge of the first conduit element has a mating conical seating surface for the collar, and the collar is thus braceable with the annular bulge by placing on and tightening the profile clamp.
The conical seating surface of a thus-configured clamp surface can serve as part of the centering surface, for the seating of the flanged collar of the corrugated hose end on such a conical surface inherently insures the desired centering according to the invention in all three directions.
In order to facilitate the installation of the uncoupling element and to increase its accuracy, the centering surface preferably includes a cylindrical shoulder arranged between the annular bulge and the flame pipe.
To diminish the inherent ability of the corrugated hose to vibrate, the corrugated hose can be constructed with multiple walls, preferably with three wall layers. The friction between the individual wall layers, in connection with vibratory motions of the corrugated hose, provides for the internal damping of these motions.
The invention displays particular advantages when the corrugated hose has a high internal rigidity, and indeed such that its internal frequency lies higher than the excitation frequency of the internal combustion engine and/or of its auxiliary units. Especially because the danger of resonance vibrations is hereby eliminated, an additional damping of the corrugated hose by a knit jacket or a knit hose is dispensable. This makes it possible for the overall constru

Affiliated with

Also associated with

Rating

Uncoupling element for uncoupling vibrations does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Uncoupling element for uncoupling vibrations, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Uncoupling element for uncoupling vibrations will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2590224