DE102016120372A1 - Conduit with several coaxial tubes - Google Patents

Abstract

The invention relates to a line element (100) for exhaust pipes, which has a coaxial construction of an inner tube (IS), a middle tube (MS), and an outer tube (AS). Typically, the inner tube (IS) and the outer tube (AS) are formed by metal winding tubes and the middle tube (MS) by a gas-tight diaphragm bellows or bellows. Preferably there is a distance (d) between the middle tube (MS) and the outer tube (AS) so that these tubes do not touch each other.

Description

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 the DE 20 2015 104 177 U1 Various embodiments of line elements are known, which consist of an inner tube and an outer tube, wherein at least one of the hoses is usually gas-tight. Further prior art can be found in the DE 10 2008 001 297 A1 . DE 10 2011 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 utilization properties.

This object is achieved by a conduit element according to claim 1. Advantageous embodiments are contained in the subclaims.

• - einem Innenschlauch;
• - einem den Innenschlauch umgebenden Mittelschlauch;
• - einem den Mittelschlauch umgebenden Außenschlauch.

The conduit element according to the invention for exhaust pipes is characterized by the following coaxial arrangement of (at least) three hoses:

• - an inner tube;
• - 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 to arrange the inner tube in the middle tube and the middle tube in the outer tube. That is, the clear inner diameter of the center tube must be greater than the outer diameter of the inner tube, and the clear inner diameter of the outer tube greater than the outer diameter of the middle tube.

The coaxial arrangement of at least three hoses according to the invention makes it possible to provide a line element with improved properties. 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 an improved thermal insulation of the line 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 gas inlet side and exhaust gas outlet side.

The hoses of the line element, in particular the inner tube and / or the outer tube, are preferably wound hoses, in particular metallic 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 for example in the DE 20 2015 104 177 U1 described.

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 tubes can then be optimized in terms of other functions, such 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 bellows are typically made from a tube by hydroforming in connection with an upsetting operation, bellows and diaphragm bellows in the profile region are welded, rotationally symmetric or helically corrugated elements having either undulations that are perpendicular to the axis of rotation 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 used for example in the DE 10 2008 001 297 A1 or the DE 10 2011 053 131 A1 described. 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 at a (radial) distance from the middle tube, so that there is an annular gap between the middle tube and the 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 chosen so large that it does not come even during operation of the line element to a touch of the two hoses. Furthermore, a (thermal) insulation material (woven fabric, glass fiber or the like) can optionally be arranged in the annular gap between the middle tube and the outer tube.

According to a preferred embodiment of the embodiment described above, the distance between the center hose and outer hose is approximately 0.01 to 2.6 times the wall height of the center hose, the "wall height" being defined as the difference between the maximum and minimum diameters of the center hose along its axial extent assumes. In a bellows, the wall height corresponds to the height of the hose waves (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) is arranged at a distance from the central tube, said distance is preferably 0.01 to 2.6 times the wall height of the central tube. For this embodiment, the statements made above with respect to the distance between central tube and outer tube apply analogously.

In order to prevent contact between inner tube and middle tube (or outer tube and middle tube) during operation and to dampen noise, a damping element can be arranged between inner tube and middle tube (and / or between outer tube and middle tube). This may in particular be a metal knit, for example according to the 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 the DE 10 2012 013946 A1 be removed.

Typically, the conduit element is designed so that it expires at at least one, preferably at both axial ends to a predetermined connection diameter at which the connection to an exhaust system (engine or remaining exhaust gas lines) 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 connection element may for example be a piece of pipe which includes a transition from the connection radius to the radius of a hose.

• 1 die vergrößerte Ansicht eines axialen Endes eines Leitungselementes mit einem Membranbalg als Mittelschlauch und einem Abstand zwischen Mittelschlauch und Innenschlauch;
• 2 das Leitungselement von 1 in einem axialen Schnitt entlang seiner gesamten axialen Erstreckung;
• 3-5 Abwandlungen des Leitungselementes von 1 und 2.

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

• 1 the enlarged view of an axial end of a conduit member with a diaphragm bellows as the center tube and a distance between the center tube and the inner tube;
• 2 the line element of 1 in an axial section along its entire axial extent;
• 3 - 5 Modifications of the line element of 1 and 2 ,

• - einem radial am weitesten innen liegenden Innenschlauch 110 (allgemein mit dem Bezugszeichen „IS“ versehen);
• - einem den Innenschlauch 110 umgebenden gasdichten Mittelschlauch 120 (allgemein mit dem Bezugszeichen „MS“ versehen);
• - einem den Mittelschlauch 120 umgebenden und radial am weitesten außen liegenden Außenschlauch 130 (allgemein mit dem Bezugszeichen „AS“ versehen).

The 1 and 2 show an axially extending section through a conduit element 100 according to a first embodiment of the present invention. The pipe element 100 is characterized by a coaxial arrangement of three tubes, as follows:

• - A radially inner innermost inner tube 110 (generally indicated by the reference "IS");
• - one the inner tube 110 surrounding gastight middle tube 120 (generally designated by the reference "MS");
• - one the middle tube 120 surrounding and radially outermost outer tube 130 (generally provided with the reference symbol "AS").

While the inner tube IS and the outer tube AS are designed as metal winding tubes with agraffförmiger binding, it is at the middle tube to a gas-tight diaphragm bellows 130 ,

The outer diameter of the inner tube 110 is smaller than the inner diameter of the middle tube 120 so that an annular gap of thickness d _lM remains between the hoses.

Likewise, the inner diameter of the outer tube 130 larger than the outer diameter of the middle tube 120 , so that an annular gap of thickness d _AM remains between the two hoses.

Compared with the wall height h of the middle tube 120 , ie the difference between the outer diameter and the inner diameter of the middle tube, preferably the following conditions apply to the above-mentioned spacings or thicknesses of the annular gaps:

The ratios (d _AM / h) and / or (d _lm / 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 as 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. In the example shown, the terminal end E is realized constructively that the outer tube 130 on a first connection element 131 is fixed, which rests on its inner side and then merges under stepped radius reduction on the connection radius of the connection end. Analog is the middle tube 120 on a second connection element 121 attached, which abuts on its inner side and then merges under step-shaped increase in radius on the connection radius of the terminal end, wherein it is within the first connection element 131 to come to rest. The inner tube 110 can be coupled in a similar manner to a connection element or be expanded in a manner not shown radially to the connection radius and from the inside to the second connection element 121 issue.

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.

2 shows a section over the entire axial extent of the conduit element 100 from 1 , It can be seen that in the annular gap between the inner tube 110 and middle tube 120 two (or a different number) of damping elements 115 are arranged from metal knit.

3 shows a conduit element 200 in which, in a modification of the conduit element of 1 and 2 the middle hose MS through a bellows 220 is formed.

4 shows a conduit element 300 in which, in a modification of the conduit element of 1 and 2 the inner tube 310 the middle tube 320 touched (ie the distance d _IM is zero).

5 shows a conduit element 400 in which, in a modification of the conduit element of 4 the middle hose MS through a bellows 420 is formed.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 202015104177 U1 [0002, 0008]
• DE 102008001297 A1 [0002, 0010]
• DE 102011053131 A1 [0002, 0010]
• DE 102010037162 A1 [0002, 0014]
• DE 102015102258 [0002, 0015]
• DE 102012013946 A1 [0002, 0015]

Claims (10)

Conduit element (100, 200, 300, 400) for exhaust pipes, comprising a coaxial arrangement of - an inner tube (IS, 110-410), 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. Pipe element (100, 200, 300, 400) according to at least one of the preceding claims, characterized in that the middle hose (MS) is a corrugated bellows, a winding bellows or a diaphragm bellows. Conduit element (100, 200, 300, 400) according to at least one of the preceding claims, characterized in that the outer tube (AS) is arranged at a distance (d _AM ) to the central tube (MS). Line element (100, 200, 300, 400) after Claim 5 , characterized in that the distance (d _AM ) is 0.01 to 2.6 times the wall height (h) of the center tube (MS). Conduit element (100, 200) according to at least one of the preceding claims, characterized in that the inner tube (IS) is arranged at a distance (d _IM ) from the central tube (MS), this distance preferably being 0 to 2.6 times the wall height (FIG. h) of the middle tube (MS). Conduit element (100, 200) according to at least one of the preceding claims, characterized in that a damping element (115, 215) is arranged between the inner tube (IS) and 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) 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 (111, 121, 131), which allows a gas-tight transition to a terminal end (E) of the conduit element.

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