EP1680615A1

EP1680615A1 - Pipe joint

Info

Publication number: EP1680615A1
Application number: EP04790905A
Authority: EP
Inventors: Rolf Fadini; Sandra Gnann; Friedrich Gugel; Martin RÖHM; Hans-Jürgen STRASSNER
Original assignee: DaimlerChrysler AG; PETER HUFNAGEL GmbH
Current assignee: PETER HUFNAGEL GmbH; Mercedes Benz Group AG
Priority date: 2003-10-30
Filing date: 2004-10-27
Publication date: 2006-07-19
Also published as: US20070090645A1; DE10350682A1; WO2005043025A1

Abstract

The invention relates to a pipe joint for connecting a first pipe part (1) to a second pipe part (2), especially for an exhaust gas system of an internal combustion engine. Said pipe joint comprises a fastening means (3) and a sealing element (4) that is provided with a sleeve (5) and a sealing ring (6). According to the invention, the first end (7) of the sleeve (5) is provided with a radial enlargement (8) and can be inserted into the first pipe part (1) in such a way that said enlargement (8) engages behind a peripheral constriction (11) of the first pipe part (1). The inventive pipe joint is suitable particularly for gas-tightly connecting exhaust pipes of motor vehicles.

Description

Pipe connection

The invention relates to a pipe connection for connecting two pipe parts, in particular for an exhaust system of an internal combustion engine, having the features of the preamble of claim 1.

U.S. Patent No. 1,959,630 discloses an apparatus for connecting two tubing members having a sleeve and a sealing ring wrapped around the sleeve. To connect the pipe parts, the sleeve is partially inserted into one of the pipe parts and the other part of the pipe plugged onto the free sleeve part. By means of a clamp, which is placed and tightened around the flared ends of the pipe parts, the pipe parts are pressed axially with their flared ends towards each other and against the sealing ring, so that a solid pipe connection is formed.

In contrast, it is an object of the invention to provide a pipe connection for connecting two pipe parts, in particular for an exhaust system of an internal combustion engine, which allows a simplified assembly.

This object is achieved by a pipeline connection with the features of claim 1. The pipe connection according to the invention has a sealing element with a sleeve and a sealing ring and is characterized in that the sleeve has a radial widening at its first end and can be inserted into the first conduit part such that the widening engages behind a peripheral constriction of the first conduit part. By this constructive measure according to the invention, the sealing element is axially fixed in the pipe part after insertion ^¬ ben. This has the advantage that it can not slide out of the pipe part during assembly, in particular in the case of an approximately perpendicular pipe.

In an embodiment of the invention, the radial expansion of the sleeve is formed tooth-like abkragend. Preferably, the widening in the circumferential direction is limited by notches and comparatively narrow. This reduces when inserting the sealing element required to overcome the Umfangseinschnürung force. It is advantageous to provide a few, distributed symmetrically along the circumferential end of the sleeve Abkragungen, thereby tilting during assembly is avoided.

In a further embodiment of the invention, the sleeve has a conical taper at its second end. As a result, the attachment of the second line part is facilitated.

In a further embodiment of the invention, the sealing ring encloses the sleeve annular and is positively connected to the sleeve. The sealing ring is therefore fixed in position at an intended location of the sleeve all around and can not be removed from the sleeve during insertion of the sealing element slide. It is advantageous if the sealing ring encloses the sleeve frictionally. In particular, the sealing ring can be permanently connected to the sleeve, resulting in a one-piece sealing element.

In a further embodiment of the invention, the sealing ring in cross-section frustoconical shape with a straight approach, wherein the radially outer region has a smaller width than the radially inner region. Due to the partially frusto-conical cross-section oblique flanks arise at which can be pressed form-fitting at expanded ends of the line parts to be joined. As a result, a high tightness is achieved, which is particularly important for connecting the exhaust pipe parts. Due to the broadened straight approach, with which the sealing ring with the sleeve is in communication, results in a mechanically stable and robust sealing element.

In a further embodiment of the invention, the sealing ring is constructed of a graphite filled wire mesh. By the knitted wire on the one hand a certain strength is achieved, at the same time, however, a change in shape is possible, whereby the sealing ring can be pressed flush against a sealing surface, even if it has certain unevenness.

In a further refinement of the invention, the first line part and the second line part each have a funnel-shaped widening at their connection-side end. In the case of a sealing ring with an at least partially frusto-conical cross section, it is advantageous if the expansion angle of the conduit parts at least approximately corresponds to the flank angle of the sealing ring, so that when merging the pipe parts these rest with their widening on the flanks.

In a further embodiment of the invention, the fastening means is designed as an open clamp at at least one point with cross-sectionally inclined flanks and a radially projecting closure part. When the pipe end areas are widened, the flanks of the clamp engage behind the widenings of the pipe parts. Preferably, the flank angle of the clamp here corresponds approximately to the AufWeitungen the line parts. Preferably, a screw connection for the closure part of the clamp is provided, with which it can be tightened and thereby the line parts are pressed against each other and against the sealing ring, so that a solid pipe connection is formed.

Advantageous embodiments of the invention are illustrated in the drawings and described below. Showing:

1 shows a preferred embodiment of the pipe connection according to the invention in a schematic cross-sectional representation,

Fig. 2 is a schematic fragmentary cross-sectional view of a preferred embodiment of the pipe joint associated sealing element and

Fig. 3 shows a preferred embodiment of the pipe connection according to the invention in a schematic perspective view. In Fig. 1, a preferred embodiment of the pipe connection according to the invention in the assembled state is shown schematically in cross section. By means of a sealing element 4 and a clamp 3, a first conduit part 1 is connected to a second conduit part 2. The first conduit part 1 has a Umfangseinschnürung 11, which merges into a funnel-shaped expansion 12. Although not absolutely necessary, it is advantageous, for the sake of the production of identical parts, to carry out the second line part 2 as shown in its end region as the first line part 1. Overall, the pipe connection is such that a gas-tight connection of the pipe parts 1, 2 is achieved. It is assumed that a preferred gas flow direction according to the arrow 14.

The sealing element 4 according to the invention comprises a sleeve 5 with an approximately centrally disposed, circumferential sealing ring 6. The sleeve 5 has at a first end 7 to a radial expansion 8. The illustration of FIG. 1 is based on a cross-sectional profile through two diametrically opposed widenings. The sleeve 5 also has at its second end 9 a conically tapering portion 10. Preferably, the sealing ring β is formed so that in cross-section a radially outwardly tapering truncated cone results with a straight lug, with which the sealing ring 6 rests on the outside of the sleeve 5 on the outside.

For mounting the pipe connection, the sealing element 4 is inserted into the first conduit part 1. In this case, when the widening 8 of the sleeve 5 strikes the peripheral constriction 11 of the conduit part 1, the widened peripheral region 8 is pressed inwards and, upon further insertion of the sleeve 5, springs back into its starting position and engages behind the peripheral constriction 11. In this way, an axial fixation of the sealing element 4, so that it can no longer slide out of the conduit part 1 in the course of further assembly occurs, the truncated cone of the sealing ring 6 comes into contact with the flared end 12 of the conduit part. This facilitates assembly, in particular in the case of a geodetically downward course of the line part 1.

For mounting, it is advantageous between three and ten preferably tooth-like abkragend trained widenings

8 evenly distributed along the circumferential line of the sleeve end 7 provide. With more widening results in an increased force when pressing the sealing element 5 in the conduit part 1, while it can lead to tilting with less widening. It is further advantageous for the sleeve 5 between the end regions 7, 9 to provide an outer diameter which is only slightly smaller than the inner diameter of the conduit part 1 in the region of the peripheral constriction 11, so that the sleeve rests there. The Umfangsseinschnürung 11 is preferably such that at this point results in a reduction of the inner diameter of the conduit parts 1, 2 by about 1% to 4%.

For further assembly, the second conduit part 2 is attached to the conically tapered end 9 of the sleeve until the funnel-shaped flared end 13 rests against the flank of the sealing ring 6. Here, the conical taper 10 of the sleeve proves to be advantageous in two respects. On the one hand, an oblique attachment of the second line part 2 is made possible to a certain extent, which is useful, for example, in hard-to-reach exhaust pipes. On the other hand results between the sleeve 5 at the end

9 and the second conduit part 2, a circumferential gap 15, so that the pipe connection can be designed slightly angled and thus a certain deviation from a straight wiring is possible. Preferably, the conically tapered end portion of the sleeve 5 extends axially in the flow direction to behind the Umfangsseinschnürung of the second conduit part second

A solid and preferably gas-tight connection of the conduit parts 1, 2 is achieved by means of the clamp 3 with an approximately U-shaped cross-section. For this purpose, the clamp 3 is placed around the flared ends 12, 13 of the conduit parts 1, 2, so that the flanks of the clamp overlap the latter. It is advantageous if the flank angle of the clamp 3 and the sealing ring 6 about the flank angle of the flared ends 12, 13 of the conduit parts 1, 2 correspond. Preference is given to an angling of the ends 12, 13 by about 70 ° with respect to the line axis. The clamp 3 can be designed in a conventional design with at least one open point. Advantageously, for example, a clamp with two semicircular halves, which are movably connected at one end and closed at the other end with a screw and tightened. During tightening, the clamp can slide in the direction of the circumferential constrictions of the pipe parts 1, 2, whereby the sealing ring 6 is pressed sealingly against the flared ends 12, 13 of the pipe parts 1, 2. In this case, a sliding axial deformation of the sealing ring 6 is made possible by the fact that this has a radially inner portion of rectangular cross-section.

For the handling and assembly of the pipe connection according to the invention, it is advantageous if the sealing ring β is fixed in position on the sleeve 5 is arranged. This can, for example, by a circumferential annular bead of Sleeve 5 can be achieved in cooperation with a corresponding circumferential groove on the bearing surface of the sealing ring 6. It is preferable to connect the sealing ring 6 positively and optionally non-positively with the sleeve, whereby a captive is guaranteed.

For a gas-tight pipe connection in an exhaust system of an internal combustion engine, it is advantageous if the sealing ring 6 has a corresponding temperature resistance and deformability. It is therefore intended to construct the sealing ring 6 of a temperature-resistant sealing material. Although other sealing materials such as Kevlar, aluminum or copper can be used, it is advantageous if the sealing ring is composed of an at least partially, but preferably of a predominantly filled with graphite wire mesh. The use of graphite or a predominantly graphite-containing sealing material results in good sliding properties, which prevents seizure of the sealing ring. Graphite also has good thermal and chemical resistance. The knitted wire ensures sufficient deformability and flexibility as well as mechanical cohesion of the graphite. The knitted wire further prevents radial flow away of the sealing material and thus a loosening of the pipe connection. In addition, the fixed, preferably non-detachable connection of the sealing ring 6 to the metallic sleeve 5 is made possible by the use of the wire mesh, whereby a one-piece sealing element 4 is formed.

With regard to the radial strength of the sealing ring 6, it is advantageous if, together with the sleeve 5, the total outside diameter of the sealing element 4 reached reaches the largest diameter of the widened end 12, 13 of the conduit section. le 1, 2 does not exceed, so that a radial projection is avoided. Particularly preferred is a slightly smaller largest diameter of the sealing element 4, as shown in Fig. 1. With regard to the width of the sealing ring 6, it is advantageous if this is so dimensioned that there is an axial distance of the pipe parts, which is about 5% to 50% of the pipe diameter.

Reference will now be made to a preferred embodiment of the sealing element 4 and in particular the sleeve 5 with reference to FIG. 2. In this case, the same components are provided with the same reference numerals with reference to FIG. As shown in Fig. 2, the radial expansion 8 of the sleeve 5 is performed at an angle of α with respect to the axial course of the sleeve 5. For this angle α, a range of 15 ° to 35 ° is preferred. Particularly preferably, the radial expansion 8 is performed at an angle of α of about 25 ° and extends in the axial direction in a length of about 0.5% to 10%, preferably about 5% based on the length of the sleeve 5. The conical taper 10 of the sleeve diameter at the second end 9 of the sleeve 5 is preferably carried out with a cone angle ß of about 5 ° to 25 °. Particularly preferred is a cone angle ß of about 15 °. With regard to a connection of exhaust pipes of a motor vehicle and the usual dimensions there, the conical taper 10 preferably extends about 1% 30%, more preferably about 15% based on the length of the sleeve 5 in the axial direction.

Fig. 3 shows a schematic perspective view of the assembled pipe joint of FIG. 1, wherein like components are provided with the same reference numerals. 3, only a short part of the line part 1 is shown. while the connected second line control is not shown. According to Fig. 3, the tooth-like abkragende widening 8 of the sleeve 5 only a small part of the circumference of the sleeve 5 and is limited by an axial notch. For exhaust pipes of about 80 mm in diameter, a width of about 1 mm to 3 mm for the tooth-like abkragende expansion 8 is advantageous. For other diameters corresponding relative dimensions. Although several tooth-like expansions may be provided, in FIG. 3, for the sake of clarity, only a tooth-like, projecting, widening is shown.

For the closure of the clamp 3, a screw 17 is provided, to which the clamp 3 in the region of the closure has radially angled ends 15 which can be tightened by the screw 17, so that the clamp 3 axially compresses the line point. However, other common closure forms, such as a clamp for the clamp 3 are applicable.

Claims

Pipe connection for connecting a first line part (1) and a second line part

(2), in particular for an exhaust system of an internal combustion engine, with a fastening means

(3) and a sealing element (4), which has a sleeve (5) and a sealing ring (6), characterized in that the sleeve (5) has a radial widening (8) at its first end (7) and thus in the First line part (1) can be inserted so that the widening (8) engages behind a circumferential constriction (11) of the first line part (1).

Pipe connection according to claim 1, so that the radial widening (8) of the sleeve (5) is cantilevered.

Pipe connection according to claim 1 or 2, characterized in that the sleeve (5) has a conical taper (10) at its second end (9).

4. Pipe connection according to one of claims 1 to 3, d a d u r c h g e k e n n z e i c h n e t that the sealing ring (6) surrounds the sleeve (5) in an annular shape and is positively connected to the sleeve (5).

5. Pipe connection according to one of claims 1 to 4, d a d u r c h g e k e n n z e i c h n e t that the sealing ring (6) is frustoconical in cross section with a straight extension, the radially outer region having a smaller width than the radially inner region.

6. Pipe connection according to one of claims 1 to 5, d a d u r c h g e k e n n z e i c h n e t that the sealing ring (6) is constructed from a wire mesh filled with graphite.

7. Pipe connection according to one of claims 1 to 6, so that the first line part (1) and the second line part (2) each have a funnel-shaped widening (12; 13) at their connection-side end.

8. Pipe connection according to one of claims 1 to 7, characterized in that the fastening means (3) as an open clamp at least at one point with an oblique cross-section Flanks and a radially projecting closure part is formed.