Fluid connection system for a heat exchanger

Abstract

The present invention relates to a connection system (20) for a heat exchanger, the system comprising: - a metal structure (22, 24) comprising a fluid inlet or outlet opening; - a pipe fitting (34) mounted on the metal structure (22, 24) in a leak-tight manner, forming a connection with the opening (32), the pipe fitting (34) comprising at least one lug (342, 344); - a device (40) for keeping the pipe fitting (34) pressed against the metal structure (22, 24), the device (40) comprising at least one stud (28, 26) that passes through the lug (342, 344) and is secured to the metal structure (22, 24), and at least one locking element (38, 36) for locking the lug (342, 344) in place along the stud (28, 26), the stud (28, 26) comprising at least one cavity (284, 282, 262) in which the at least one locking element (38, 36) is accommodated.

Description

[0001] FLUID CONNECTION SYSTEM FOR A FLUID EXCHANGER

[0002] HEAT

[0003] The present invention relates to the field of cooling circuits, particularly for motor vehicles, and more specifically concerns a fluid inlet or outlet connection system enabling a heat exchanger to be connected to such a circuit.

[0004] The heat exchangers in vehicle air conditioning systems are designed to allow the adjacent circulation of two different fluids in two separate spaces, so as to achieve heat exchange between these fluids without mixing them. Within the heat exchangers and the thermodynamic circuits to which they are attached, the fluids circulate under pressure.

[0005] Such an exchanger 2 is shown in Figure 1. It consists of a bundle of heat exchange plates and fluid connections 8, 10 connecting this bundle to the circuits with which the exchanger is connected. While the bundle is standard for use in several vehicles, the fluid connections are specific to each cooling circuit design intended for a particular vehicle model.

[0006] Currently, the fluid connections 8 intended for the refrigerant circulating in such an exchanger form an aluminum connection block brazed onto a cheek 6 of the exchanger 2, this cheek being an external metal plate of the exchanger 2 bordering the bundle of plates, itself arranged in an aluminum casing 4. In Figure 1, the fluid connections 8 are cylindrical orifices in the connection block, into which hoses with an aluminum end piece provided with a seal are inserted. This connection block can be adapted to a specific cooling circuit of a vehicle, in particular the arrangement of the orifices in the connection block can be different.

[0007] However, the production of this connection block by machining limits the design possibilities, in particular the shape of the orifices in the connection block. It is indeed difficult to machine non-straight orifices in the connection block. In addition, when the orifices of the plate bundle collector take up a large area in the corners of the cheek 6, the surface area of ​​the connection block that must be brazed to the edges of the corners of the cheek 6 may prove insufficient to carry out this brazing. Finally, the current manufacture of the connection blocks of such heat exchangers requires heavy and complex brazing tools, in particular for brazing together the bundles of such heat exchangers with their connection blocks, due to the size of the necessary brazing furnace and the brazing supports that must be adapted to the different locations and connection blocks to allow their assembly on the bundles.The number of plates in the bundle is then limited to allow flat soldering of the device.

[0008] These different constraints therefore limit the different possible designs of connection block arrangements on such a heat exchanger.

[0009] There is therefore a need for a flexible, simple and easy to manufacture connection, a refrigerant connection block on a heat exchanger, which makes it easier to adapt the holes of the connection block to the different holes of the heat exchanger manifolds and to the specificities of the cooling circuits of different vehicle models.

[0010] The present invention at least partially overcomes the drawbacks of the prior art by providing a connection system for a heat exchanger, a heat exchanger and a method of assembling the connection system according to the invention, which allow great freedom in designing the fluid connections of the heat exchanger.

[0011] To this end, the invention provides a connection system for a heat exchanger, the connection system comprising:

[0012] - a metal structure comprising a fluid inlet or outlet orifice,

[0013] - a tube mounted tightly on the metal structure, forming a connection with the fluid inlet or outlet orifice, the tube comprising at least one ear,

[0014] - a device for maintaining the compression of the tubing against the metal structure, the system being characterized in that the compression holding device comprises at least one stud passing through the ear and secured to the metal structure, and at least one element for blocking the ear along the stud, the stud comprising at least one housing in which the at least one blocking element is housed.

[0015] By means of the invention, the heat exchanger is firstly brazed or welded with the metal structure and the stud(s) of the compression holding device, these studs preferably being metallic, then in a second stage the tubing, preferably made of a synthetic material (plastic), is compressed along the stud(s). Alternatively, another material is chosen to make the tubing, for example metal. This allows the tubing to be mounted and dismounted elsewhere than at the brazing or welding station and therefore provides flexibility for the packaging of the heat exchanger.

[0016] Furthermore, the invention makes it possible to optimize the diameters of the inlet and outlet orifices of the exchanger when these are positioned in the corners of the external metal plate, compared to the solutions of the prior art. Indeed, since the pipes are made of synthetic material, they do not need to be brazed onto a cheek of the heat exchanger. Finally, since they are not necessarily machined, they can be of very diverse shapes.

[0017] The connection system according to the invention of course preferably comprises both an inlet pipe and an outlet pipe, each associated with a fluid inlet or outlet orifice, and a compression holding device associated with each pipe.

[0018] The invention applies both to the fluid connections of the heat exchanger intended for the heat transfer fluid of the heat exchanger, and to the fluid connections of the heat exchanger intended for the refrigerant fluid, although the invention is more specifically intended for the latter option.

[0019] In an exemplary embodiment of the invention, the housing of the stud of the compression holding device of the connection system according to the invention comprises a threaded hole, the locking element comprising a screw capable of being screwed into the threaded hole by passing through a protrusion of a tube end piece intended to be mounted in a sealed manner on the tubing. Indeed, the tubing is intended to receive an aluminum end piece of a hose. In this exemplary embodiment of the invention, the hose comprises a protrusion, for example an ear, in which a screw presses the protrusion against the ear of the tubing by screwing into the threaded hole. The ear of the tubing thus compresses the tubing against the metal structure, ensuring the sealing of the connection system. The tubing indeed comprises a sealing member, for example a seal, or an overmolding, on its surface of contact with the metal structure.

[0020] Preferably, the stud comprises a circular groove forming the housing, the locking element being in the form of a clip, the clip comprising two arms, and the ear comprising two through holes each receiving one of the two arms of the clip, the two arms enclosing the stud while being housed in the circular groove. This embodiment of the invention does not require specific assembly with the hose, but is compatible with the previous embodiment insofar as the compression holding device possibly has several locking elements housed in several housings of the stud.

[0021] Preferably again, the tubing comprises another ear, the metal structure comprising another stud secured to the metal structure and passing through the other ear. The compression holding device preferably comprises a locking element for the other ear along the other stud, the other stud comprising a housing in which the locking element is housed. This locking element is for example a staple or a screw as mentioned above. The other stud is also preferably a metal stud brazed or welded to the metal structure.

[0022] In an exemplary embodiment of the invention, the metal structure comprises a cheek of the heat exchanger and a complementary plate welded or brazed against the cheek of the heat exchanger, the stud being integral with the complementary plate. This complementary plate provides more space for fixing the pipes to the inlet and outlet ports of the collector of the plate bundle of the heat exchanger. The other stud is for example positioned on a surface of the complementary plate extending beyond the cheek.

[0023] Advantageously, the metal structure comprises a device for indexing the complementary plate on the cheek and / or the stud on the cheek. This indexing device makes it possible to correctly position the orifices of the complementary plate on those of the cheek of the heat exchanger, and the pipes on the orifices of the collector of the heat exchanger.

[0024] The indexing device comprises, for example, at least one collar capable of being inserted into a corresponding opening in the complementary plate and / or of receiving the stud.

[0025] In one embodiment, the connection system according to the invention comprises an overmolded seal fixed to the cheek of the heat exchanger, on the contour of the fluid inlet or outlet orifice, this overmolded seal being capable of enveloping at least in part the base portion of the tubing.

[0026] In one embodiment, the tubing comprises a base portion proximal to the metal structure, and a connection portion connected to the base portion, the connection portion having a smaller cross-section than the base portion. This feature makes it possible to form a pre-chamber in the tubing. This pre-chamber is advantageous in the case where the orifice of the collector opposite the tubing has a larger cross-section than the connection portion. Without this pre-chamber, the sudden widening of the cross-section of the refrigerant circuit, at the level of the cheek of the heat exchanger, generates poor distribution of the refrigerant at the level of the first plates of the plate bundle of the heat exchanger. By offsetting this widening at the level of the pre-chamber, the distribution of the refrigerant in the heat exchanger is improved.

[0027] By "proximal" here we mean that the base portion is closer to the metal structure than the connection portion, which is intended to receive a hose end fitting.

[0028] The base portion preferably has an internal contour that is substantially identical to the contour of the fluid inlet or outlet orifice. This feature helps to avoid pressure losses. By "substantially" is meant that the internal contour of the base portion overlaps the fluid inlet or outlet orifice to within one or two millimeters.

[0029] The base portion extends, for example, over a height of between 2.5 and 13 millimeters. It is, for example, triangular or rectangular in cross-section. The connecting portion is, for example, circular in cross-section.

[0030] In an exemplary embodiment, the base portion comprises at least one groove receiving a sealing member, for example a seal.

[0031] The invention also relates to a heat exchanger comprising at least one bundle of plates and at least one connection system according to the invention.

[0032] The invention finally relates to a method of assembling a connection system according to the invention, said method comprising the steps of:

[0033] - securing the pad to the metal structure,

[0034] - insertion of the ear of the tubing on the plot,

[0035] - compression of the ear along the stud and blocking of the ear via the blocking element.

[0036] The heat exchanger according to the invention and the assembly method according to the invention have advantages similar to those of the connection system according to the invention. Other characteristics and advantages of the invention will become apparent from the following description on the one hand, and from several exemplary embodiments given for informational and non-limiting purposes with reference to the appended schematic drawings on the other hand, in which:

[0037] [fig 1] already commented in relation to the prior art, illustrates a heat exchanger of the prior art,

[0038] [fig 2] represents in perspective a face of a metallic structure of a connection system according to the invention, according to a first embodiment of the invention,

[0039] [fig 3] represents in perspective an opposite face of the metallic structure of figure 2, in the first embodiment of the invention,

[0040] [fig 4] represents in perspective a connection system according to the invention, in the first embodiment of the invention,

[0041] [fig 5] represents in perspective a tubing of a connection system according to the invention in the first embodiment of the invention,

[0042] [fig 6] represents in perspective a connection system according to the invention in a second embodiment of the invention,

[0043] [fig 7] represents in perspective a metallic structure of the connection system of figure 6, and

[0044] [fig 8] represents in perspective a tube of the connection system of figure 6.

[0045] According to a first embodiment of the invention shown in Figure 2, a connection system 20 according to the invention for a heat exchanger, comprises a metal structure consisting of the cheek 22 of the heat exchanger, closing a bundle of metal plates of the heat exchanger, and a complementary plate 24 welded or brazed onto the cheek 22 of the heat exchanger. The cheek 22 and the complementary plate 24 are therefore metallic, for example made of aluminum.

[0046] The cheek 22 and the complementary plate 24 comprise two orifices 30 and 32 intended to overlap the fluid inlet and outlet orifices of the heat exchanger. For example, the orifice 30 is a refrigerant inlet orifice, and the orifice 32 is a refrigerant outlet orifice. The orifices 30 and 32 are therefore of identical or substantially identical section to those of the heat exchanger collector. By substantially identical, it is meant that the orifices 30, 32 overlap those of the heat collector to within one or two millimeters.

[0047] In order to facilitate the correct superposition of the complementary plate 24 on the cheek 22, in particular at the level of the orifices 30 and 32, an indexing device for the cheek 22 makes it possible to assist in the positioning of the complementary plate 24 on the cheek 22. In this first embodiment of the invention, this indexing device comprises two collars 222 and 224 on the cheek 22, which are inserted into corresponding orifices in the complementary plate 24. These collars 222 and 224 also serve to each position a metal stud on the complementary plate 24. In this exemplary embodiment, the collar 224 serves to position a stud 28, metallic and secured by brazing or welding, in the collar 224. Another stud 26, metallic, is positioned on the complementary plate 24 thanks to an orifice 25 (visible in FIG. 3) in the complementary plate 24, in which is screwed the stud 26.Alternatively, the stud 26 is welded or brazed to the complementary plate 24, the orifice 25 only serving to receive a protrusion of the stud 26. In another alternative, the studs 26 and 28 are made from the same material as the complementary plate 24.

[0048] In yet another variant, the indexing device comprises, for example, pins on the cheek 22, which are inserted into corresponding orifices in the complementary plate 24, and the complementary plate 24 comprises a device for positioning the metal stud 28, for example a pin or a collar.

[0049] The studs 26 and 28 are used to position a tube 34 of the connection system 20 according to the invention, shown in FIG. 4, on the complementary plate 24. For this, the tube 34 has two ears 342 and 344 into which the stud 28 and the stud 26 are inserted respectively. The tube 34 is preferably made of synthetic material, that is to say made of polymers (plastic material). Alternatively, the tube 34 is made of aluminum or another metal.

[0050] In this first embodiment of the invention, a tube such as the tube 34 is mounted in a sealed manner against each fluid inlet or outlet orifice 30, 32. There are therefore in fact four metal studs on the complementary plate 24 to position these two tubes, only the studs 26, 28 and the tube 34 being shown in FIGS. 2 to 4. It is clear that the two tubes have too large a footprint to be mounted together only on the cheek 22 of the heat exchanger, hence the presence of the complementary plate 24 making it possible to receive at least one ear and one stud corresponding to a tube. Thus, the ear 344 and the stud 26 are positioned on a surface of the complementary plate 24 which extends beyond the cheek 22.

[0051] It follows that in the case where the fluid inlet and outlet orifices of the heat exchanger allow pipes to be mounted in a sealed manner on these orifices without projecting beyond the flat surface of the cheek 22, the complementary plate 24 is not necessary. In this configuration, illustrated in a second embodiment of the invention described later, the metal studs allowing the pipes to be positioned are therefore directly brazed or welded onto the cheek 22.

[0052] In addition to the ears 342 and 344, the tubing 34 comprises a base portion 346, as shown in FIG. 5, and a connection portion 348 axially extending the base portion 346. By axially, is meant in an axial direction parallel to the longitudinal direction of the studs 26, 28, that is to say to the direction of flow of the refrigerant fluid in the tubing 34.

[0053] The base portion 346 is pressed against the complementary plate 24 by means of a sealing member (not shown), in particular a seal mounted in a groove 345 hollowed out in the contact surface of the base portion 346 with the complementary plate 24. As a variant, the sealing member is an overmolding carried out on this contact surface.

[0054] The internal section of the base portion 346, along a plane orthogonal to this axial direction, is identical or substantially identical to the shape of the orifice 32, that is to say that the internal section of the base portion 346 and the orifice 32 overlap exactly, or to within one or two millimeters. This internal section extends over a height, that is to say along the axial direction, of 2.5 to 13 millimeters from the external surface of the base portion 346 on which the sealing member is mounted, to the connection portion 348.

[0055] At the junction between the base portion 346 and the connection portion 348, there is a sudden variation in the internal section of the tubing 34, the internal section of the connection portion 348 being smaller than the internal section of the base portion 346. In this first embodiment of the invention, the internal section of the base portion 346 is triangular, while the internal section of the connection portion 348 is circular. These internal sections of the connection portion 348 and the base portion 346 are connected by a wall substantially orthogonal to the axial direction, so as to form a pre-chamber inside the base portion 346. By substantially orthogonal is meant orthogonal with a tolerance of plus or minus five degrees of deviation from a strictly orthogonal direction. This pre-chamber makes it possible to improve the distribution of the refrigerant fluid in the plate bundle of the heat exchanger.

[0056] Of course, as a variant, the internal section of the base portion 346 is of a different shape, for example rectangular or circular. The connection portion 348 being intended to receive a hose, the end piece of which is made of aluminum and includes a seal, the shape of the section of the connection portion 348 is preferably circular.

[0057] In order to ensure the seal between the complementary plate 24 and the tubing 34, the connection system 20 according to the invention comprises a device 40 for maintaining the compression of the tubing 34 against the complementary plate 24, as shown in FIG. 4. This compression maintaining device 40 comprises, in this first embodiment of the invention, two clips 36 and 38. The arms of each of these clips 36, 38 are housed both in each of the respective ears 344 and 342, and in respective circular grooves 282 and 262 of the studs 28 and 26, these circular grooves being visible in FIG. 2. To do this, the two arms of each clip 36, 38 are mounted by sliding in two through orifices 3442 (visible in FIG. 5) of each of the ears 344 and 342, once these mounted on the pads 26, 28.Then the free ends of the arms of the clips 36, 38 are folded back, as seen in Figure 4, which makes it possible to lock the compression of the tubing 34 onto the complementary plate 24.

[0058] In addition to this compression of the tubing 34 by the clips 36, 38, the compression holding device 40 comprises a threaded hole 284 on the stud 28. In fact, the hose connecting to the tubing 34 comprises a protrusion, for example an ear, which a screw (not shown) of the compression holding device 40 passes through by screwing into the threaded hole 284. This screw therefore makes it possible to hold the hose against the tubing 34 which keeps the latter in compression against the complementary plate 24. In particular, this screw presses the protrusion of the hose against a surface 3422 of the ear 342. The ear 342 extends axially to the complementary plate 24 to allow this compression of the hose against the ear 342, to compress the ear 342 against the complementary plate 24.An orifice 347 in the ear 342 of the tubing 34 makes it possible to angularly position the protrusion of the hose on the ear 342 to allow this screwing, the protrusion of the hose comprising a positioning pin complementary to this orifice 347.

[0059] Of course, the other tubing of the connection system 20, forming a fluid connection with the orifice 30, comprises a compression holding device similar to the compression holding device 40.

[0060] Alternatively, the compression holding device 40 comprises only one of the clips 36, 38, or only the threaded hole 284 and the screw for holding the hose against the ear 342, or a threaded hole in each of the studs 26, 28, these threaded holes each cooperating with a protrusion and a screw for holding the hose against the ear 342, or a combination of these possibilities.

[0061] A method of assembling the connection system 20 according to the invention will now be described, relative to the first embodiment of the invention, on a bundle of plates of a heat exchanger, relative to the tubing 34 only for simplicity. This method comprises the following steps:

[0062] The first step is the positioning of the complementary plate 24 on the cheek 22 of the heat exchanger using the collars 222 and 224.

[0063] The next step is the positioning of the studs 28, 26 in the collars 222 and 224.

[0064] The next step is the brazing of the heat exchanger equipped with the cheek 22 on which the complementary plate 24 and the pads 26, 28 are positioned. For this, the assembly of cheek 22, complementary plate 24 and pads 26, 28 is positioned on the bundle of plates of the heat exchanger.

[0065] The next step is the positioning of the tubing 34 on the orifice 32 by inserting the studs 28, 26 into the respective ears 344, 342.

[0066] The next step is the compression of the ears 344, 342 along the studs 28, 26 and the blocking along these studs 28, 26, of these ears held in compression, by mounting the respective staples 38, 36 in the through holes 3442 of the ears 344 and 342 and in the circular grooves 282 and 262.

[0067] The next step is to lock this compression hold by folding the free ends of the staples 28, 36.

[0068] Finally, the last step is possibly a check of the tightness of the connection system 20. In a variant where there is no additional plate 24, the first steps are of course the positioning of the pads in the collars 222, 224, then the brazing of the heat exchanger equipped with the cheek 22 and the pads 26, 28.

[0069] Similarly, in the variant where the studs 26, 28 are integral with the complementary plate 24, we go directly from the step of positioning the complementary plate 24 on the cheek 22 to the brazing step. The same applies if the studs 26, 28 are screwed onto the complementary plate 24 before the latter is positioned on the cheek 22.

[0070] According to a second embodiment shown in Figures 6, 7 and 8, a connection system 50 for a heat exchanger comprises a metal structure consisting of the cheek 52 of the heat exchanger, closing a bundle of metal plates of the heat exchanger. The connection system 50 also comprises a tube 64 mounted on the cheek 52, and forming a sealed connection with a fluid inlet or outlet orifice 62 (referenced Figure 7) arranged on the cheek 52.

[0071] In Figure 6, a single pipe 64 is shown, but the heat exchanger of course preferably comprises at least two pipes, a fluid inlet pipe and a fluid outlet pipe, in accordance with the connection system 50 according to the invention.

[0072] As in the first embodiment of the invention, the tubing 64 comprises a base portion 646, and a connection portion 648 axially extending the base portion 646, that is to say parallel to the direction of flow of the refrigerant fluid leaving the cheek 52. The structural characteristics of the base portion 646 and of the connection portion 648 are similar to those of the tubing 34 of the first embodiment of the invention and are therefore not detailed further here.

[0073] Unlike the first embodiment, in this second embodiment of the invention, the positioning of the tubing 64 on the cheek 52 is achieved by fitting at least a portion of the base portion 646 of the tubing 64 into an overmolded seal 54 fixed to the contour of the orifice 62 of the cheek 32. This overmolded seal 54 axially extends the contour of the orifice 62 by flaring slightly to tightly surround the base portion 646 of the tubing 64 over at least a portion thereof in the axial direction. The overmolded seal 54 therefore has a section, orthogonal to the axial direction, of a shape complementary to the section of the base portion 646, here a triangular section.

[0074] The base portion 646 is pressed against an internal surface of this overmolded seal 54, in particular against a groove 644 (visible in FIG. 8) hollowed out in the contact surface of the base portion 646 with the overmolded seal 54.

[0075] Furthermore, in this second embodiment of the invention, the connection system 50 comprises a stud 58 brazed onto the cheek 52 and extending orthogonally to the main extension dimension of the cheek 52, i.e. axially, towards the outside of the cheek 52. A collar 522 arranged on the cheek 52 makes it possible to position the stud 58 before it is brazed onto the cheek 52. When positioning the tubing 64 in the overmolded seal 54, the stud 58 is inserted into an ear 642 of the tubing 64. The stud 58 also comprises a threaded hole 584 intended to receive a screw (not shown) passing through a protrusion of a hose connecting to the tubing 64. This screw maintains the protrusion in compression against a surface 6422 of the ear 642, this which compresses the ear 642 and therefore the tube 64 against the cheek 52.

[0076] An orifice 647 in the ear 642 of the tubing 64 makes it possible to angularly position the protrusion of the hose on the ear 642 to allow this screwing, the protrusion of the hose comprising a positioning pin complementary to this orifice 647.

[0077] The stud 58 and the screw therefore constitute, in the connection system 50 according to the invention, a device for maintaining the compression of the tubing 64 against the cheek 52.

[0078] In this second embodiment, only one stud 58 per tube 64 of the connection system 50 according to the invention is necessary, and the compression holding device only uses the screw associated with the hose which connects to the tube 64.

[0079] In this second embodiment of the invention, a method of assembling the connection system according to the invention on a bundle of plates of a heat exchanger, relative to the tubing 64 comprises the following steps:

[0080] The first step is the positioning of the pad 58 in the collar 522. The next step is the brazing of the heat exchanger equipped with the cheek 52 on which the pad 58 is positioned. For this, the cheek 52 and pad 58 assembly is positioned on the plate bundle of the heat exchanger.

[0081] The next step is the positioning of the overmolded seal 54 on the cheek 52.

[0082] The next step is positioning the tubing 64 against the orifice 62 by fitting the tubing 64 into the overmolded seal 54 and inserting the stud 58 into the ear 642.

[0083] The next step is the compression of the ear 642 along the stud 58 and the blocking along this stud 58 of the ear 642 held in compression, by screwing a screw held in a protrusion of a hose in the threaded hole 584 of the stud 58 and by connecting the hose in the tubing 64.

[0084] Finally, the last step is possibly a verification of the tightness of the connection system 50. Of course, the invention is not limited to the examples which have just been described and numerous adjustments can be made to these examples without departing from the scope of the invention.

Claims

CLAIMS 1- Connection system (20) for a heat exchanger, the connection system (20) comprising: - a metal structure (22, 24) comprising a fluid inlet or outlet orifice (32), - a tube (34) mounted in a sealed manner on the metal structure (22, 24), forming a connection with the fluid inlet or outlet orifice (32), the tube (34) comprising at least one ear (342, 344), - a device (40) for maintaining compression of the tubing (34) against the metal structure (22, 24), the system being characterized in that the compression holding device (40) comprises at least one stud (28, 26) passing through the ear (342, 344) and secured to the metal structure (22, 24), and at least one locking element (38, 36) of the ear (342, 344) along the stud (28, 26), the stud (28, 26) comprising at least one housing (284, 282, 262) in which the at least one locking element (38, 36) is housed. 2- Connection system (20) according to claim 1, in which the housing (284) comprises a threaded hole, the locking element (38, 36) comprising a screw capable of being screwed into the threaded hole by passing into a protrusion of a tube end piece intended to be mounted in a sealed manner on the tubing (34). 3- Connection system (20) according to claim 1 or 2, in which the stud (28, 26) comprises a circular groove (282, 262) forming the housing (282, 262), the locking element (38, 36) being in the form of a clip (38, 36), the clip (38, 36) comprising two arms, and the ear (342, 344) comprising two through orifices (3442) each receiving one of the two arms of the clip (38, 36), the two arms enclosing the stud (28, 26) while being housed in the circular groove (282, 262). 4- Connection system (20) according to any one of claims 1 to 3, in which the tubing (34) comprises another ear (344), the metal structure (22, 24) comprising another stud (26) secured to the metal structure (22, 24) and passing through the other ear (344). 5- Connection system (20) according to claim 4, in which the compression holding device (40) comprises a locking element (36) of the other ear (344) along the other pad (26), the other pad (26) comprising a housing (262) in which the locking element (36) is housed. 6- Connection system (20) according to any one of the preceding claims, in which the metal structure (22, 24) comprises a cheek (22) of the heat exchanger and a complementary plate (24) welded or brazed against the cheek (22) of the heat exchanger, the stud (28, 26) being integral with the complementary plate (24). 7- Connection system (20) according to the preceding claim, in which the metal structure (22, 24) comprises a device for indexing the complementary plate (24) on the cheek (22) and / or the stud (28) on the cheek (22). 8- Connection system (20) according to the preceding claim, in which the indexing device comprises at least one collar (222, 224) capable of being inserted into a corresponding opening of the complementary plate (24) and / or of receiving the stud (28). 9- Connection system (20) according to any one of claims 6 to 8 taken in dependence on claim 4, in which the other pad (26) is positioned on a surface of the complementary plate (24) extending beyond the cheek (22). 10- Connection system (20) according to any one of the preceding claims, in which the tubing (34) comprises a base portion (346) proximal to the metal structure (22, 24), and a connection portion (348) connected to the base portion (346), the connection portion (348) being of smaller section than that of the base portion (346). 11- Heat exchanger comprising at least one bundle of plates and at least one connection system (20) according to any one of the preceding claims. 12- Method for assembling a connection system (20) according to any one of claims 1 to 10, said method comprising the steps of: - securing the stud (28, 26) to the metal structure (22, 24), - insertion of the ear (342, 344) of the tubing (34) on the stud (28, 26) - compression of the ear (342, 344) along the stud (28, 26) and blocking of the ear (342, 344) via the blocking element (38, 36).

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