FR2649469A1 - Tube, particularly for an exhaust pipe for a motor vehicle, and including at least one connection member - Google Patents

Abstract

The invention relates to a tube forming an integral part, particularly, of an exhaust pipe for a motor vehicle and in which is mounted at least one connection member such as a flange or the like. This tube is characterised in that it includes retaining means 4, 5 located on either side of the connection member 3 for immobilizing the latter at least in terms of translation on the said tube 1. The invention relates to the motor industry and more particularly to the field of exhaust pipes.

Description

 The invention relates to a tube forming an integral part, in particular, of an exhaust line for a motor vehicle and on which is mounted at least one connecting member such as a flange or the like.

 The present invention will find its application, more particularly, in the field of the automobile industry.

 Several elements constitute an exhaust line for the combustion gases of a motorized vehicle such as an automobile. In particular, these exhaust lines include one or more silencers connected to each other by means of tube sections of variable shape and size, adapted to said vehicle.

 It should be noted that these exhaust lines consist, in certain cases, of several parts connected to each other by means of suitable assembly means. In all cases, they comprise in their front part, a connection end piece intended to be connected to the combustion gas collector at the level of the engine. Therefore, on such exhaust lines, are necessarily arranged one or more connecting members such as flanges or the like allowing them to be connected to said manifold or which are capable of ensuring the connection of two parts of the same line. .

 Taking the example of the flange fitted, usually, the free end of the tube constituting the connection end piece, this flange is generally welded to this tube. However, this type of assembly, although commonly used, has a certain number of drawbacks, in particular because of the multiple constraints which the exhaust lines for vehicles undergo.

 Indeed, these exhaust lines, ensuring the evacuation of the combustion gases from an engine, are subjected to high temperatures before resulting in a significant test of all of the members as well as the various assemblies. In particular, the temperature is at the origin of non-negligible amplitude expansions of the materials used. However, since this coefficient of expansion is not always identical from one room to another, high tensions are created at their junction.

 Furthermore, the arrangement of these exhaust lines under the vehicle exposes them to corrosive agents as well as to frequent thermal shocks due, for example, to projections of cold water on certain parts of the exhaust line in temperature. .

 This combination of the effect of temperature and various stresses, as well as the stresses produced by a welded joint, makes the latter particularly sensitive to the action of corrosion. As a result, it is common for an exhaust line to yield at the level of either its connection to the manifold or at the level of the connections of the various parts which compose it.

 On this, it should be added that a weld connecting a flange or the like to a tube generally causes a restriction of the internal channel of the latter and requires the use of flanges of sufficient thickness to avoid their deformation under the action. stresses produced by welding. In addition, it should be noted that due to the imperatives of assembly and assembly at high speed of the vehicles, it is essential to prevent any axial displacement of the flange or any other connecting member on the tube so as to avoid its prior positioning during this assembly. Such a condition is, in particular, necessary in the context of an assembly produced by means of robotic machines.

 However, it may also prove advantageous, in order to facilitate this mounting, to allow, in certain measures, the rotation of the connecting member on the tube, a function which cannot be ensured by means of an assembly by welding.

 In fact, the present invention aims to remedy all of the aforementioned drawbacks by proposing a type of assembly of connecting members on a tube, in particular, of an exhaust line subjected to the temperature which is in able to avoid possible local constraints at the level of said tube favoring the action of corrosive agents.

 To this end, the invention relates to a tube forming an integral part, in particular of an exhaust line for a motor vehicle and on which is mounted at least one connecting member such as a flange or the like, characterized in that 'It comprises retaining means located on either side of the connecting member (3) to immobilize the latter at least in translation on said tube.

 The advantages obtained thanks to this invention consist, essentially, in that it is no longer necessary to carry out a weld to ensure the connection of a flange or the like on a tube, weld which weakens, locally, the exhaust line and, in any case, represents a particularly long operation, of difficult realization and with random results.

 Another advantage obtained thanks to the present invention resides in the fact that a better sealing of the exhaust line is obtained, both at the level of the connection of two parts of separate lines and at the junction of this line. exhaust to the flue gas collector connected to the vehicle engine. This better sealing is, moreover, obtained while allowing wider machining tolerances, in particular, as regards the connecting members such as flanges.

 Other objects and advantages of the present invention will become apparent from the following description. This is given, however, only for information and not limitation.

The understanding of this description will be facilitated by referring to the attached drawing in which
- Figure 1 is a schematic sectional view of a tube end on which is mounted, according to the invention, a connecting member such as a flange
- Figure 2 is a view similar to Figure 1 and corresponding to a second embodiment
- Figure 3 is a schematic sectional view of a tube section having, in its middle, a connecting member such as a flange or a bicone.

 We refer to the different figures.

 The present invention relates to a tube 1 forming an integral part, in particular of an exhaust line (not shown) of a vehicle and, more particularly, of an automobile.

 Note that these exhaust lines are intended to ensure the evacuation of the combustion gases produced by an engine and, therefore, are subjected to high temperatures.

Furthermore, their arrangement below the body of the motor vehicle causes them to be highly stressed on the one hand, due to the frequent thermal shocks due to water splashes and, on the other hand, due to their exposure to corrosive agents.

 These exhaust lines usually consist of one or more silencers connected to each other by means of tube sections comprising in their middle, in some cases, joining means making it possible to dissociate the different silencers from each other .

 These exhaust lines further include, at their rear end, an exhaust nozzle while their opposite end is provided with a connection nozzle intended to be connected to the combustion gas collector located at the level of the engine. For this purpose, this connection end piece is in the form of a tube 1 comprising, at its free end 2, a connecting member 3, such as a flange or the like capable of cooperating with a corresponding connecting member, arranged on the collector.

 Figures 1 and 2 illustrate, schematically, a tube 1 equipped with a connecting member 3 in an identical manner to a connecting piece, as mentioned above. However, this configuration of an e provided with a connecting member can be found, of course, at any other place on the exhaust line, for example at the level of the joining means connecting two parts of separate lines.

 It was mentioned above in the description, the problems posed by the assembly of a connecting member 3, such as a flange or the like, on a tube 1, in particular, due to the multiple constraints that is brought to undergo the exhaust line.

 The type of assembly commonly used to date is welding, which results in local stresses both at the level of the tube 1 and on the connecting member 3. This welding also promotes the action of corrosive agents.

 The present invention proposes to remedy the aforementioned drawbacks and to provide a solution to the problem posed by associating with the tube 1 retaining means 4, 5 located on either side of the connecting member 3, for example of the flange, to immobilize it at least in translation on said tube 1.

 According to a preferred embodiment, these retaining means 4, 5 consist, substantially, of radial deformations 6, 7 of the tube 1, produced on either side of the connecting member 3 and coming to cooperate with the front face 8 and rear 9 thereof.

 In the context of an arrangement of the connecting member 3 at the free end 2 of the tube 1, one of these radial deformations 7 consists in the arrangement of a peripheral bead on the outer periphery 11 of said tube 1 so as to create a shoulder 12 against which the rear face 9 of the connecting member 3 abuts.

 By way of indication, it will be specified that the radial deformations 6, 7 of the tube 1 can be obtained by cold deformation and following an axial stress applied to the latter.

 As for the radial deformation 6, this consists in folding, radially, the free end 2 of the tube 1 so as to create a peripheral rim constituting a shoulder 13 cooperating with the front face 8 of the connecting member 3.

 In view of the above description, it is understood that the radial deformations 6, 7 constituting the retaining means 4, 5, ensure the immobility, in the axial direction, of the connecting member 3 on the tube 1 In this regard, it should be noted that if it proves to be judicious to prevent the rotation of this connecting member 3 on the tube 1, it suffices to act on the deformation parameters of the latter. so as to obtain an axial and radial tightening of the connecting member 3 on said tube 1. In the same way, by intervening on these same parameters, it will be possible to immobilize, in translation, such a connecting member 3 on the tube 1 while allowing its rotation relative to the latter in order to facilitate its angular positioning during the mounting of the exhaust line on the vehicle.

 As visible in the attached drawing, the radial deformations 6, Q, unlike a weld, do not cause any restriction of the internal diameter 14 of the tube 1, a restriction which is the cause of turbulence of the combustion gases at the inside the exhaust line and which ultimately affects engine operation and performance.

 In addition, the deformations produced cold at the level of the tube 1 avoid weakening, locally, the latter by promoting the action of corrosive agents.

 Another advantage obtained thanks to this invention consists in that the mechanical and seamless type connection makes it possible to use connecting members 3 designed in a material different from the tube 1 and having undergone a surface treatment against corrosion separately from this last.

 Furthermore, the present method of assembly, in accordance with the invention makes it possible to use a connecting member 3, such as a flange, the thickness of which is reduced to the minimum and does not undergo any prior deformation as this occurs. as part of a weld.

 Finally, another advantage obtained thanks to the present invention consists in that a tube 1 provided, at its free end 2, with a connecting member 3 immobilized by means of retaining means 4, 5, makes it possible to obtain a better seal at its junction, for example, at the manifold located on the engine or with a tube corresponding to another part of the exhaust line.

In fact, in the present case, the bearing zone 16 at the level of which it is necessary to ensure the seal between the tube 1 and the member to which it is intended to be connected is limited to the single front face 18 of the free end 2 bent, radially, of the tube 1.

 This bearing area 16 is usually within the framework of a connecting member 3 connected by welding to the tube 1, delimited by the entire front face 8 of said connecting member 3 and therefore represents a much larger surface. significant increasing the risk of leakage of combustion gases.

 Figures 2 and 3 correspond to other embodiments of the present invention.

 Thus, in the context of Figure 2, it is recommended to practice, at the front face 8 of the connecting member 3, a recess 19 in which is housed, partially, the free end 2, bent radially , of the tube 1. By reducing or, more precisely, thus optimizing, the difference between the bearing zone 16 and the front face 8 of the connecting member 3, it is possible, in particular, within the framework of a flange, to limit the deformation of the latter and, indirectly, the tightening torque at the time of assembly.

 In Figure 3, there is illustrated a tube 1 equipped, in its middle 21, with a connecting member 3 which can be either a flange or a bicone. Such a configuration is found, in particular, in one-piece exhaust lines.

These connecting members, such as flanges or bicones allow, after cutting of the one-piece exhaust line, the assembly of spare parts intended to replace the damaged line section.

 In this case, the radial deformations 7, 7A, produced on either side of the connecting member 3 to immobilize the latter, in particular, in translation on the tube 1 are in the form of peripheral beads arranged on the outer periphery 11 of said tube 1. These peripheral beads thus define two shoulders 12, 12A, cooperating respectively with the rear face 9 and the front face 8 of the connecting member 3.

 Apart from the advantages both of reliability and of longevity which a tube provides, equipped with a connecting member and in accordance with the invention, it should be specified that it also contributes to a lower manufacturing cost of the line. exhaust requiring an implementation time less than a tube provided with a welded connecting member.

 In sum and in view of the foregoing, it can be seen that the present invention corresponds to real progress by providing a solution to both the technological and economic problem posed by the assembly of a connecting member on a tube, in particular of an exhaust line subject to high temperatures and any other stress.

 Although the invention has been described with reference to a particular embodiment, it is understood that it is in no way limited thereto and that it is possible to make various modifications to it in terms of shapes, materials and combinations of these various elements, without departing from the scope and spirit of the invention.

Claims (8)

Claims  1. Tube forming an integral part, in particular, of an exhaust line for a motor vehicle and on which is mounted at least one connecting member (3), such as a flange or the like, characterized in that it comprises retaining means (4, 5) located on either side of the connecting member (3) to immobilize the latter at least in translation on said tube (I).  2. Tube according to claim 1, characterized in that the retaining means (4, 5) are constituted by radial deformations (6, 7, 7A) of the tube (1) produced on either side of the connecting member (3) and coming to cooperate with the front (8) and rear (9) thereof.  3. Tube according to claim 2, characterized in that the radial deformations (7, 6) of said tube (1) correspond, respectively, to a peripheral bead arranged on the outer periphery (11) of the tube (1) so as to create a shoulder (12) against which abuts the rear face (9) of the connecting member (3) and at a free end (2) of this tube (1) folded radially to form a peripheral rim defining a second shoulder (13) cooperating with the front face (8) of said connecting member (3).  4. Tube according to claim 2, characterized in that the radial deformations (7, 7x) of said tube (1) both correspond to peripheral beads arranged on the outer periphery (11) of the tube (1) so to define two shoulders (12, 12A) cooperating, respectively, with the rear face (9) and the front face (8) of the connecting member (3).  5. Tube according to claims 3 and 4, characterized in that the radial deformations (6, 7, 7A) of the tube (1) are obtained by cold deformation and following an axial stress applied to the latter.  6. Tube according to claim 3, characterized in that the connecting member (3) comprises, at its front face (8), a recess (19) in which is housed, partially, the free end (2) bent radially, from the tube (1).  7. Tube according to claim 3, characterized in that the front face (18) of the free end (2), bent radially, of the tube (1) constitutes a support zone (16) capable of cooperating with a other member, such as an exhaust gas collector or the like to which the line or part of the exhaust line should be connected.  8. Tube according to claim 1, characterized in that the retaining means (4, 5) ensure the locking in rotation and in translation of the connecting member (3) on said tube (1 :.