WO2018077613A1 - Line element consisting of a plurality of coaxial hoses - Google Patents

Abstract

The invention relates to a line element (100) for exhaust gas pipes, which has a coaxial structure made of an inner hose (IS), a central hose (MS) and an outer hose (AS). The inner hose (IS) and the outer hose (AS) are typically formed by wound hoses made of metal, and the central hose (MS) is formed by a gas-tight membrane bellows or a corrugated bellows. Preferably, there is a distance (dAM) between the central hose (MS) and the outer hose (AS), so that said hoses are not in contact.

Description

 WESTFALIA Metal Hose Technology GmbH & Co. KG

At the Schwanenweiher 1

57271 Hilchenbach

Conduit made of several coaxial tubes

The invention relates to a conduit element for exhaust gases, which can be used for example in motor vehicles for decoupling vibrations between the engine and subsequent parts of the exhaust system.

From DE 20 2015 104 177 U1 are different embodiment of

Line elements known, which consists of an inner tube and a

Outer tube consist, with at least one of the hoses is usually gas-tight. Further prior art can be found in DE 10 2008 001 297 A1, DE 10 201 1 053 131 A1, DE 10 2010 037 162 A1, DE 10 2015 102 258, and DE 10 2012 013946 A1. All of these documents are incorporated by reference in their entirety in this application.

Against this background, it was an object of the present invention

To provide line elements with improved usage characteristics.

This object is achieved by a conduit element according to claim 1.

Advantageous embodiments are contained in the subclaims.

The pipe element according to the invention for exhaust pipes is characterized by the following coaxial arrangement of (at least) three hoses: an inner hose; a middle tube surrounding the inner tube; an outer tube surrounding the middle tube. Inner tube, middle tube and outer tube can in principle all have the same structure. They differ essentially by the different diameters, which allow the inner tube in the

Middle hose and the middle hose in the outer hose to arrange. This means that the clear inner diameter of the middle tube must be greater than the outer diameter of the inner tube, and the clear

Inner diameter of the outer tube larger than the outer diameter of the middle tube.

By the coaxial arrangement according to the invention of at least three

Hoses can be a conduit element with improved properties

to be provided. Each of the three hoses can be optimized for a specific function. In particular, it is possible to provide mechanical protection for the inner tubes through the outer tube, for example against stone chipping. Furthermore, the outer tube leads to improved thermal insulation of the

Conduit element, so that along the axial extent of the

Line element forms a balanced temperature profile and thereby adjusts a small temperature difference between the exhaust inlet side and the exhaust gas outlet side.

The hoses of the line element, in particular the inner tube and / or the outer tube, are preferably

Winding hoses, especially around metallic winding hoses. Such winding tubes are known in various embodiments (single-layer, multi-layer, agraffförmig, with inner scales and / or outer scales, etc.).

Typical embodiments are described for example in DE 20 2015 104 177 U1.

In principle, two or all three hoses of the line element can be gas-tight. For gas tightness of the entire line element, however, it is sufficient if only one of the three tubes, preferably the middle tube, is gas-tight. The other hoses may then be in relation to others

Functions are formed optimized, for example, as winding tubes. In principle, all three hoses of the conduit element can be designed as a corrugated bellows, a winding bellows, or a membrane bellows. While corrugated bellows typically perform in conjunction with a stuffer operation

Hydroforming are made of a tube, bellows and diaphragm bellows in the profile area welded, rotationally symmetric or helical corrugated elements that are either perpendicular to the axis of rotation

have pronounced undulations or spiral corrugations. A wound bellows structure can preferably be hooked in a form-fitting manner or welded in an overlapping or cohesive manner. Such elements are described for example in DE 10 2008 001 297 A1 or DE 10 201 1 053 131 A1.

In particular, the middle tube may be formed as a corrugated bellows, a winding bellows, or a membrane bellows, whereby it provides a high flexibility with simultaneous gas-tightness.

According to a preferred embodiment of the invention, the outer tube is arranged with a (radial) distance to the middle tube, so that there is an annular gap between the middle tube and outer tube, this condition being fulfilled at least in an axial section of the line element. The lack of contact between middle hose and outer hose friction stresses and wear are avoided. Furthermore

the resulting air gap improves the thermal insulation to the outside.

Preferably, the distance between the middle tube and outer tube is chosen so large that it does not come to a contact between the two tubes even during operation of the conduit element. Furthermore, optionally in the annular gap between middle tube and outer tube a (thermal)

Insulation material (fabric, glass fiber or the like) can be arranged.

According to a preferred embodiment of the above-described

Embodiment, the distance between middle tube and

Outer tube in about 0.01 to 2.6 times the wall height of

Middle tube, wherein the "wall height" is defined as the difference between the maximum and the minimum diameter, the

Middle tube along its axial extent assumes. With a bellows The wall height corresponds to the height of the hose shafts (radius difference between wave crest and wave trough). In absolute terms, the distance between center hose and outer hose is typically about 5 mm.

In a further embodiment of the invention, the inner tube

(At least in an axial section of the conduit member) arranged at a distance from the central tube, said distance is preferably 0.01 to 2.6 times the wall height of the center tube. For this embodiment, the above apply with respect to the distance between

Middle hose and outer hose made versions analog.

To make contact between inner tube and during operation

To prevent middle hose (or outer hose and middle hose) and to dampen a noise, can between inner tube and

Middle hose (and / or between outer hose and center hose) may be arranged a damping element. This may in particular be a metal knit, for example according to DE 10 2010 037 162 A1.

Each of the three hoses of the line element, in particular the

Inner tube and / or the outer tube may have a non-circular cross-section. When placing a tube with a non-circular cross-section in a tube with a round cross-section (or otherwise non-circular cross-section) can be provided via a line contact for a damped vibration behavior. Further details of such embodiments may be the

DE 10 2015 102 258 or DE 10 2012 013946 A1.

Typically, the conduit element is designed such that it at at least one, preferably at both axial ends to a predetermined

Connection diameter expires, at which the connection to an exhaust system (engine or remaining exhaust pipes) can take place. In this regard, it is preferred if inner tube, middle tube and / or outer tube have a connection element at at least one of their axial ends, which allows a gas-tight transition to a connection end of the line element. The connecting element may be, for example, a piece of pipe, which includes a transition from the connection radius to the radius of a hose.

In the following the invention will be explained in more detail by way of example with the aid of the figures. Showing:

Figure 1 is an enlarged view of an axial end of a

 Conduit element with a diaphragm bellows as the middle tube and a distance between the middle tube and the inner tube;

FIG. 2 shows the line element of FIG. 1 in an axial section along its entire axial extent;

FIGS. 3-5 Modifications of the line element of FIGS. 1 and 2

Figures 1 and 2 show an axially extending section through a conduit member 100 according to a first embodiment of the present invention. The conduit member 100 is characterized by a coaxial arrangement of three tubes, as follows: a radially innermost inner tube 110 (generally designated by the reference symbol "IS"); a gas-tight middle tube 120 surrounding the inner tube 110 (generally designated by the reference symbol "MS"); an outer tube 130 surrounding the center tube 120 and radially outermost (generally designated by the reference symbol "AS").

While the inner tube IS and the outer tube AS are designed as metal wound tubes with agraffformiger binding, it is in the middle tube to a gas-tight membrane bellows 130th

The outer diameter of the inner tube 1 10 is smaller than that

Inner diameter of the center tube 120, so that between the tubes an annular gap of thickness d | _M remains. Likewise, the inner diameter of the outer tube 130 is larger than the outer diameter of the middle tube 120, so that between the two

Hoses an annular gap of thickness 6 M remains.

Compared with the wall height h of the center tube 120, d. H. the difference between the outer diameter and the inner diameter of the

Middle tube, preferably apply the following conditions for the o.g.

Distances or thicknesses of the annular gaps:

The ratios (d _A M / h) and / or (d | _M / h) are preferably greater than 0, greater than 0.01, greater than 0.05, greater than 0.1, greater than 0.5, or greater than 1, or greater than 1 .5, greater than 2.0 or greater than 2.5. Further, they are preferably smaller than 2.5, smaller than 1 .8, smaller than 1 .3, smaller than 0.9, or smaller than 0.5, or smaller than 0.1 or smaller than 0.05.

So that the line element 100 can be connected to an exhaust system, has at its two axial ends in each case a terminal end E, at which it ends with a predetermined connection radius. Im shown

For example, the terminal end E is structurally realized in that the outer tube 130 is mounted on a first connection element 131, which rests on its inner side and then merges under step-shaped radius reduction to the connection radius of the connection end. Analog is the

Middle tube 120 attached to a second connection element 121, which rests on its inner side and then merges under step-shaped increase in radius on the connection radius of the connection end, wherein it comes to rest within the first connection element 131. The inner tube 1 10 may be coupled in a similar manner to a connection element or be expanded in a manner not shown radially to the connection radius and bear against the second connection element 121 from the inside.

It should be expressly understood that the described embodiment of the terminal end is to be understood only as an example and also numerous other constructions come into question for this purpose. Figure 2 shows a section over the entire axial extent of

Conduit element 100 of Figure 1. It can be seen that in the annular gap between the inner tube 110 and the middle tube 120 two (or another number) of damping elements 15 are arranged made of metallic knit.

FIG. 3 shows a line element 200 in which, in a modification of FIG

Conduit element of Figure 1 and 2 of the central tube MS by a

Bellows 220 is formed.

FIG. 4 shows a line element 300 in which, in a modification of FIG

Conduit element of Figure 1 and 2 of the inner tube 310 the

Middle tube 320 touched (ie, the distance d | _M is zero).

FIG. 5 shows a line element 400 in which, in a modification of FIG

Conduit element of Figure 4, the middle tube MS is formed by a bellows 420.

Claims

claims Conduit element (100, 200, 300, 400) for exhaust pipes, comprising a coaxial arrangement of  an inner tube (IS, 1 10-410), a middle tube (MS, 120-420) surrounding the inner tube (IS), an outer tube (AS, 130-430) surrounding the middle tube (MS). Conduit element (100, 200, 300, 400) according to at least one of the preceding claims,  characterized in that the inner tube (IS) and / or the  Outer tube (AS) is a metal winding tube. Conduit element (100, 200, 300, 400) according to at least one of the preceding claims,  characterized in that the middle tube (MS) is gas-tight. Conduit element (100, 200, 300, 400) according to at least one of the preceding claims, characterized in that the middle tube (MS) is a corrugated bellows, a winding bellows or a diaphragm bellows. 5. line element (100, 200, 300, 400) according to at least one of the preceding claims,  characterized in that the outer tube (AS) with a  Distance {6 M) to the middle tube (MS) is arranged. 6. conduit element (100, 200, 300, 400) according to claim 5,  characterized in that the distance (Ü AM) is 0.01 to 2.6 times the wall height (h) of the center tube (MS). 7. line element (100, 200) according to at least one of the preceding claims,  characterized in that the inner tube (IS) with a Distance (d | _M ) to the central tube (MS) is arranged, said distance is preferably 0 to 2.6 times the wall height (h) of the  Medium hose (MS) is. 8. line element (100, 200) according to at least one of the preceding claims,  characterized in that between the inner tube (IS) and the middle tube (MS), a damping element (1 15, 215) is arranged. 9. line element (100, 200, 300, 400) after at least one of  previous claims,  characterized in that the inner tube (IS) and / or the Outer tube (AS) has a non-circular cross-section. Conduit element (100, 200, 300, 400) according to at least one of the preceding claims, characterized in that the inner tube (IS), the Middle tube (MS) and / or the outer tube (AS) at least one axial end of a connection element (1 1 1, 121, 131), which allows a gas-tight transition to a terminal end (E) of the conduit element.