FR2991037A1 - HEAT EXCHANGER WITH REINFORCED COLLECTOR - Google Patents

Abstract

The invention relates to a heat exchanger comprising a heat exchange body 2, at least a cover 4 and a collector 3 connecting the cover 4 to the heat exchange body 2 by means of a crimping device from the collector 3 and folded over the cover 4, the heat exchange body 2 comprising a plurality of tubes 6a, 6b able to channel a first fluid, the collector 3 comprising a bottom plate 24 surrounded by an edge 13 for securing the cover 4, characterized in that the bottom plate 24 and the fastening edge 13 delimit a housing 26 for receiving a heel 15 of the cover 4, the joining edge 13 being formed by a doubled wall 16, one end 17 of which is secured to at least one tube 6a, 6b.

Description

The technical sector of the present invention is that of heat exchangers configured to perform a heat exchange between a first fluid and a second fluid, more particularly intended to be installed in a motor vehicle. Such a heat exchanger is, for example, a supercharged air cooler. A motor vehicle can conventionally be equipped with an internal combustion engine combined with a turbocharger. This causes a rise in the temperature of the intake gas, which affects the correct filling of the combustion chambers of the engine. This is the reason why it is known to complete this configuration by the addition of a heat exchanger, the function of which is to cool the intake gases before their entry into these combustion chambers, which makes it possible to increase the density of the inlet gases and thus improve the stoichiometric ratio in the combustion chambers. Such a heat exchanger conventionally comprises a plurality of tubes in which the inlet gases circulate, the spaces between the tubes being for their part traversed by a cooling fluid. At the inlet or outlet of this exchanger, the inlet gases are channeled by a lid secured to a manifold, the latter being configured to sealingly receive the end of each tube through which the inlet gases enter.

New supercharging techniques make their appearances. It is thus known to combine the internal combustion engine with two or three turbochargers. This combination is accompanied by an increase in the pressure and the temperature of the inlet gases. The mechanical stresses experienced by the charge exchangers become extremely important, since the pressure of the inlet gases can reach 4 bars. Heat exchangers known to date are therefore not adapted to withstand such pressure or temperature levels, and leakage may occur in particular to the right of the junction connecting the cover to the collector. Document US2003 / 0217838A1 discloses a solution for reinforcing a peripheral edge of the collector. Although improving the situation, such a solution is however not suitable for air / air heat exchanger designs, undergoing a high internal pressure and where a cover is retained on the manifold by means of mechanical crimping. Crimped jointing has certain advantages, but it is more sensitive to the phenomena of deformation of the cover and thermal expansion, these phenomena being less problematic in the case of a joining of the cover by welding on the collector. There is thus a need to improve the management of the seal between the internal volume of the heat exchanger and its environment for heat exchangers crimped cover.

The object of the present invention is therefore to solve the disadvantage described above mainly by reinforcing the peripheral edge of the manifold, the latter being particularly designed to receive and secure by crimping a lid. The invention proposes to provide stress recoveries on a component of the heat exchange body, in particular on the tube or tubes through which the inlet gases subjected to high pressure pass. The invention therefore relates to a heat exchanger comprising a heat exchange body, at least one cover and a collector connecting the cover to the heat exchange body with a crimping device from the collector and folded on the lid, the heat exchange body comprising a plurality of tubes adapted to channel a first fluid, the manifold comprising a bottom plate surrounded by a lid fastening edge, characterized in that the bottom plate and the edge of fastening delimit a receiving housing of a heel cover, the fastening edge being formed by a lined wall, one end of which is secured to at least one constituent tube of the heat exchange body. The fastening of the end of the lined wall on at least one tube thus ensures a recovery of mechanical forces which contributes significantly to increasing the mechanical strength of the fastening edge against the constraints generated by the pressure or the temperature of the first. fluid capable of circulating inside the heat exchanger according to the invention.

It will be noted that the heat exchange body may also comprise a multiplicity of dissipation devices interposed between the tubes and in contact with a second fluid able to pass through the heat exchange body. According to a first characteristic of the invention, the end of the doubled wall is secured to a plurality of tubes. It is intended here the case where the end extends along a longitudinal face of the exchanger, the end then being brazed to a side wall of several tubes bordering the longitudinal face. According to a second characteristic of the invention, a tube comprises two longitudinal walls joined to one another by two side walls, the fastening edge comprising a strip transverse to the bottom plate and secured against at least one of the side walls. at least one tube over a length of at least 1 mm.

According to another characteristic of the alternative or complementary invention, the end is secured against a longitudinal wall of a terminal tube of the heat exchange body. One or the other of the solutions mentioned below makes it possible to provide for a recovery of mechanical forces along the relevant face of the exchanger, and advantageously on all the faces which delimit the heat exchange body. According to another characteristic of the invention, the heat exchange body is finished laterally by a cheek installed at a distance at least equal to 0.1 mm from the doubled wall, this distance being a minimum to avoid brazing between the two elements concerned. .

According to yet another characteristic of the invention, a dissipation device is interposed between the cheek and the end tube, the dissipation device being at a distance at least equal to 0.1 mm from the doubled wall, this distance being a minimum to avoid soldering between the two elements concerned.

The two technical solutions presented above make it possible to thermally decouple the collector from the cheek and / or the dissipation device, which offers the possibility of avoiding mechanical stresses resulting from differences in thermal expansion between the collector in contact with the collector. first fluid, and the cheek and / or the dissipation device, in contact with the second fluid. The exchanger according to the invention can be configured so that a distance at least equal to 2 mm is provided between the bottom plate and the end of the doubled wall. Such a distance makes it possible to form a strut by means of the brazed end on the tube. Such a strut opposes a phenomenon of opening of the fastening edge under the effect of the pressure in the lid, which increases the level of reliability of the sealing by crimping.

Advantageously, the bottom plate comprises at least one opening in which is housed a tube end, said opening being bordered by a collar turned towards the heat exchange body. Such an arrangement makes it possible to obtain a face of the base plate turned towards the substantially flat cover, which contributes to improving the mechanical strength of the heat exchanger. Such an exchanger may comprise a seal installed in the receiving housing, at least between the heel of the cover and the securing edge.

The lined wall is formed by a first wall and a second wall brazed against the first wall. According to a first alternative, the first and second walls come from the same metal sheet and connected to one another by a fold. According to a second alternative, the second wall is preliminarily separated from the first wall and then attached to it before a soldering step. The lined wall may comprise at least one angle to the right of which is provided a mechanical reinforcement device. The latter prevents the angular inclination formed between the two parts of the lined wall which border the angle increases under the effect of pressure. According to an exemplary embodiment, the mechanical reinforcement device is in particular a chamfer formed on the angle of the first wall. Alternatively, this mechanical reinforcement device is advantageously a fillet formed on the angle of the second wall. It will be appreciated that this reinforcing device may also be formed by the combination of the chamfer and the fillet, provided on one or the other of the walls. Such an arrangement makes it possible to generate shapes that combine to oppose the mechanical stresses that the collector has undergone. The first wall may comprise a first band forming a bottom of the housing and a first sidewall delimiting laterally the housing, the first band and the first side being connected by the chamfer. According to another characteristic of the invention, the second wall may comprise a second band brazed against the first band, and a second side brazed against the first side, the second band and the second side being connected by a fillet remote from the first band. chamfer. The fillet and the chamfer form here the device of mechanical reinforcement, and such a distance between this fillet and this chamfer contributes significantly to increase the mechanical strength of the joining edge. Advantageously, the end comprises a fold arranged so that a face of the second wall is brazed against the tube. Such an arrangement increases the bonding surface, especially brazing, between the lined wall and the tube or tubes at the end. According to an exemplary embodiment, the crimping device may comprise a plurality of crimping tabs from the first wall, which in the final state of manufacture of the heat exchanger, are folded over the heel of the lid. The invention may also cover an intake gas cooling system of an internal combustion engine of a motor vehicle, comprising a heat exchanger incorporating any of the features described above, wherein the first fluid is formed by the intake gas of the internal combustion engine, while the second fluid is formed by a flow of air outside the vehicle. An advantage of the invention lies in the possibility of increasing in a simple manner the mechanical strength of the collector, in particular of its securing edge. The fastening of the end generates an additional contact point on the tubes which then forms a recovery of forces, the latter significantly limiting the deformations of the fastening edge when the heat exchanger is subjected to pressure and / or temperature important internal Thus, a heat exchanger, provided with a doubled wall collector and whose end of this wall is secured to at least one tube channeling the first fluid, can withstand high pressures and high temperatures. .

Other features, details and advantages of the invention will emerge more clearly on reading the description given below as an indication in relation to drawings in which: FIG. 1 is a perspective view of a heat exchanger; heat according to the invention, - Figure 2 is a perspective view of the heat exchanger according to the invention, partially showing two adjacent faces of this exchanger, and its collector, - Figure 3 is a view illustrating the joining together of the collector on a lateral face of the heat exchange body, in section along the plane A illustrated in FIG. 1; FIG. 4 is a view illustrating the joining of the collector on a longitudinal face of the heat exchange body, in section according to the plane B illustrated in Figure 1. Figure 1 illustrates an embodiment of a heat exchanger 1 according to the invention. Such a heat exchanger is in particular a supercharged air cooler used to cool the intake gases of an internal combustion engine. The heat exchanger 1 according to the invention is configured to perform a heat exchange between a first fluid and a second fluid. In particular, the heat exchanger is arranged on the one hand, for channeling a first gaseous fluid such as a supercharged air flow, and on the other hand, to be traversed by a second gaseous fluid, such as a airflow surrounding the exchanger. Thus, the heat exchanger 1 may be an air / air heat exchanger fitted to a motor vehicle, the second fluid being a dynamic air flow set in motion by the movement of the vehicle or by a motor-fan unit mounted on the vehicle. FIG. 1 comprises an orthonormal marker which defines the heat exchanger 1, the axis OX representing a longitudinal dimension or length of the exchanger, the axis OY represents a lateral dimension or width of the exchanger, while the OZ axis represents a vertical dimension or height of the heat exchanger 1 according to the invention. The heat exchanger 1 according to the invention comprises a heat exchange body 2 which forms the seat of the heat exchange between the first fluid and the second fluid. At each end of this heat exchange body 2, there is a collector 3 capped by a cover 4.

The collector 3 provides a distribution of the first fluid through a plurality of tubes 6 constituting the heat exchange body 2, the first fluid being channeled by the cover 4 to or from the collector 3. The heat exchange body 2 further comprises a multiplicity of dissipation devices 7. Each of these is interposed between two adjacent tubes 6, so as to provide a space between the tubes in which the second fluid, that is to say the air flow dynamic, circulates. According to an exemplary embodiment, a dissipation device is formed by an interlayer, in particular zigzag-shaped, and each vertex is secured to two adjacent tubes. This interlayer may include louvers. This dissipation device 7 may also be formed by a substantially flat metal sheet, on which is formed a multiplicity of louvers.

The lid 4 comprises at least one opening 5 through which the first fluid enters or leaves the heat exchanger 1. The manifold 3 is thus on one side brazed on the heat exchange body 2 and the other, rendered secured to the cover 4 by a crimping device 8 of the collector 3 on the cover 4. Such a crimping device 8 is generally formed by a set of crimping tabs folded over an edge of the cover, hereinafter called heel. The heat exchange body 2 has a rectangular section. It is thus delimited by an inlet face of the second fluid and by an outlet face of this second fluid, respectively called first longitudinal face 9 and second longitudinal face 10 of the heat exchange body 2. The latter is also delimited by a first lateral face 11 and a second lateral face 12 disposed between the first longitudinal face 9 and the second longitudinal face 10. The latter are perpendicular to the direction of movement of the second fluid, while the first side face 11 and the second side face 12 extend in planes parallel to this direction. The heat exchange body 2 comprises the plurality of tubes 6 made integral with the collector 3 by soldering. These tubes are, for example, made from a metal sheet folded on itself, so as to define an internal volume in which the first fluid flows, including the supercharged air flow.

A tube 6 is delimited by two parallel longitudinal walls, joined by two side walls. The longitudinal walls of the tubes are parallel to at least one of the lateral faces 11 or 12 which borders the heat exchange body 2. The side walls of the tubes thus extend in the plane of the first and / or second longitudinal face 9, 10 of the heat exchange body 2.

The longitudinal wall or walls of the tubes 6 extend in a plane 0X-0Y, while the side walls of the tubes 6, although rounded form, extend generally in a plane OX-OZ.

It will be noted that the structure of each tube 6 is identical, the two tubes immediately adjacent to the side faces 11 and 12 of the heat exchange body 2 being hereinafter called terminal tubes 6a and 6b. A turbulator can be installed inside the internal volume of each tube 6. This turbulator (not shown) disturbs the flow of the first fluid in the tube 6, so as to maximize the heat transfer between the first fluid and the walls defining the tube 6. This turbulator can also be secured to the two longitudinal walls of the tube so as to increase the mechanical strength of such a tube.

FIG. 2 shows the collector 3, seen at an angle formed between a first longitudinal face 9 and a first lateral face 11 of the heat exchange body 2. The collector 3 comprises a bottom plate receiving one end of the tubes 6 , invisible in this figure, surrounded by an edge 13 for securing the cover 4. The heat exchange body 2 comprises its plurality of tubes 6 between which is disposed the heat dissipating device 7, for example a spacer. The first lateral face 11 of the heat exchange body 2 is formed by a cheek 14, that is to say a metal plate, particularly rectilinear. Between the end tube 6b and this cheek 14, there is a dissipation device 7 brazed on the cheek and on the longitudinal wall of the end tube 6b.

The edge 13 for securing the lid receives a heel 15 of the lid 4 formed on a peripheral edge delimiting the opening of this lid 4. Such a heel takes the form of a shoulder made by increasing the thickness of the lid at the level of the lid. of this opening.

The fastening edge 13 is formed by a doubled wall 16, the latter extending all around the heat exchanger 1, that is to say along the two lateral faces and the two longitudinal faces defining the body. However, it will be noted that there is no lining of the fastening edge at at least one angle, and advantageously of all the angles between the lateral faces and the longitudinal faces of the heat exchange body 2. This doubled wall will be discussed in detail with reference to FIGS. 3 and 4 to come, but it may already be noted that this doubled wall 16 is formed by a first wall 21 and by a second wall 22 brazed against the first wall 21, the doubled wall further comprising a fold 23 forming a 180 ° elbow which connects the first wall 21 to the second wall 22.

The doubled wall 16 comprises at least one end 17 secured to at least one tube 6, 6a, 6b constituting the heat exchange body 2. Such a connection may occur either only along one or more lateral faces 11, 12 delimiting the heat exchange body 2, either only along one or more longitudinal faces 9, 10 delimiting the heat exchange body 2, or both along one or more lateral and longitudinal sides of the body of In the exemplary embodiment illustrated in FIGS. 1 and 2, the end 17 of the doubled wall 16 is secured along the two lateral faces and of the two longitudinal faces of the heat exchange body 2. With regard to the first longitudinal face 9, the end 17 of the doubled wall 16 is brazed to the side wall 18 of at least one tube 6, and preferably to the side wall of each constituent tube 6. of the heat exchange body 2. On the side of the first lateral face 11, the end 17 of the doubled wall 16 is brazed against the longitudinal wall 19 of the end tube or tubes 6a, 6b of the heat exchange body 2. Such brazing occurs on this longitudinal wall in the plane 0X-0Y, illustrated in Figure 1. Figure 2 also illustrates an embodiment of the crimping device 8. The latter comprises a plurality of crimping tabs 20 which are folded on the heel 15 of the cover 4. The crimping tabs 20 come from the first wall 21. FIG. 3 is a view showing in detail the positioning of the cover 4 in the manifold 3, as well as the connection between this manifold 3 and the end tube 6a or 6b. This representation illustrates a section taken in the plane A shown in FIG. 1. The collector 3 comprises a bottom plate 24 surrounded by the fastening edge 13 of the lid 4. The bottom plate 24 is provided with openings, of a shape oblong, which receive one end of each tube 6. These openings may be provided with a collar 25, for example directed towards the heat exchange body 2 or to the lid 4. The fastening edge 13 forms a peripheral belt around of the bottom plate 24, this joining edge being preferably derived from material with the bottom plate 24.

According to the invention, this edge 13 for securing the cover 4 is formed by the doubled wall 16, the latter ending at the end 17 at least partially secured to one or more tubes, in particular on one and or the other of the end tubes 6a, 6b constituting the heat exchange body 2. The term "doubled" means that the connecting edge 13 is reinforced by the provision of two thicknesses of walls clad against each other . The lined wall 16 is thus formed by a first wall 21 and a second wall 22 immediately adjacent to the first wall 21, and which follows the contours. The second wall 22 is rendered at least partially integral with the first wall 21 by a solder between these two walls. According to the exemplary embodiment shown in this figure, the first wall 21 is also secured to the second wall 22 by means of a fold. In such a case, the first wall 21 and the second wall 22 come from a same metal sheet which has been bent at 180 ° at the fold 23 to press the second wall 22 against the first wall 21. Thus it is considered that the second wall 22 is made of material with the first wall 21.

Alternatively, the second wall 22 may be a part previously distinct from the first wall 21, and attached before brazing against it, so as to form the doubled wall 16 once secured to one another, in particular by soldering .

To simplify the manufacturing method of the collector 3, a thickness of the doubled wall 16 is at least twice greater than a thickness of the bottom plate 24. In a particular embodiment, the thickness of the doubled wall 16 is strictly equal to twice the thickness of the bottom wall 24.

The thickness of the doubled wall 16 is measured in the direction OX, while the thickness of the bottom plate 24 is measured in a direction OZ, these two directions being shown in this figure.

According to the embodiment of FIGS. 3 and 4, the edge 13 for securing the lid 4 delimits, at least in part, a housing 26 for receiving the heel 15 formed at the edge of the opening of the lid 4. The bottom plate 24 is as for it prolonged by a strip 27 which extends in a direction at least transverse, and preferably perpendicular to the plane of extension of the bottom plate 24, that is to say the plane in which the openings of reception of the tube ends 6 extend. The housing 26 which receives the heel 15 of the lid is thus bordered on one side by the strip 27 and on the other by the first wall 21 constituting the doubled wall 16.

The strip 27 is here separated from the longitudinal wall 19 of the end tube 6a, 6b, because of the presence of a collar 25. In addition to receiving the heel 15 of the cover 4, this housing 26 can receive a seal 35 ensuring a sealing between the first fluid and the environment surrounding the heat exchanger according to the invention. This seal 35 is thus in abutment against the heel 15, against the strip 27 and against the first wall 21 at the housing 26.

According to the embodiment of Figure 3, the first wall 21 comprises a first band 28 extended by a first sidewall 29. The first band 28 forms the bottom of the housing 26 against which the seal 35 bears. The first flank 29 extends at least in part to the right of the housing 26, in particular laterally to it. The first band 28 and the first sidewall 29 are particularly flat. Between the first band 28 and the first sidewall 29, there is a device for mechanical reinforcement of the doubled wall 16. According to one embodiment, the mechanical reinforcement device takes the form of a chamfer 30, that is to say say a substantially flat edge and inclined relative to the first band 28 and with respect to the first sidewall 29. This chamfer 30 thus connects the first band 28 to the first sidewall 29, this chamfer being an element contributing to the mechanical reinforcement of the joining edge 13 cover 4.

The second wall 22 of the doubled wall 16 comprises a second band 31 extended by a second flank 32. The second band 31 extends in a plane parallel to the plane of extension of the first band 28, these two strips being made integral with each other. one from the other by a brazed connection. The second flank 32 extends in a plane parallel to the plane of extension of the first flank 29 and is brazed against it.

The second band 31 is joined to the second flank 32 by a fillet 33, that is to say a rounded section edge. This leave 33, as such, forms a second embodiment of the device for mechanical reinforcement of the doubled wall 16.

This leave 33 is opposite the chamfer 30, and it is configured to be separated from this chamfer 30, such an arrangement contributing to increasing the mechanical strength of the doubled wall 16. The second band 31 and the second sidewall 32 are example dishes.

This combination of the chamfer 30 with the fillet 33 forms a third variant of the mechanical reinforcement means for the doubled wall 16. It is thus clear that this mechanical reinforcement device can be formed either by the chamfer 30 or only by the fillet. 33, or by the combination of this chamfer 30 with the fillet 33, such a combination still making it possible to increase the mechanical strength of the doubled wall 16. In general, this reinforcing means can also be formed when the first wall 21 and the second wall 22 each comprise an angle, the angle formed on the first wall 21 having a shape, seen in section, different from the angle formed on the second wall 22, these two angles being opposite the one of the other.

The end 17 of the doubled wall 16 is formed by an end portion of the second band 31. According to an embodiment not shown, it is a portion of the second band 31 which is brazed against the end tube 6a, 6b.

In the example of Figure 3, the end 17 comprises a fold 34 oriented so that one or the other of the faces defining the second band 31 is supported and brazed against the end tube 6a, 6b. In this case, the fold 34 forms a 90 ° angle facing the heat exchange body 2, that is to say the opposite of the lid 4 secured to the collector 3 concerned. At the fold 23, the doubled wall 16 comprises a series of crimping tabs 20 formed by portions which extend the first wall 21. In this figure, these crimping tabs 20 are shown before folding on the heel 15 of the lid 4. In the final assembly position, these crimping tabs are pressed against the heel 15 of the cover 4, so as to exert a compressive force against the seal 35. The end 17 of the doubled wall 16 is secured against the longitudinal wall 19 of the end tube 6a, 6b of the heat exchange body 2. On the other hand, the heat exchanger is arranged so that the doubled wall 16 is not in contact with the flange 14 and / or with the dissipation device 7. To do this, the flange 14 is installed in the heat exchange body 2 so as to provide a distance at least equal to 0.1 mm of the doubled wall 16. In the example of FIG. 3, this distance is referenced D1 and she's t measured in the direction OZ between an end portion of the cheek 14 and the leave 33, or the second band 31. Advantageously, the distance D1 is at most equal to 12 mm.

Advantageously, the dissipation device 7 is interposed between the cheek 14 and the end tube 6a, 6b. The dissipation device 7 is secured in the heat exchange body 2 so as to respect a separation distance D2 of the doubled wall 16, including its end 17, at least equal to 0.1 mm. This distance D2 is measured, for example, between a last vertex of the dissipation device 7 and the second band 31, or the edge of the end 17. Advantageously, the distance D2 is at most equal to 10 mm. The end of each tube 6 is connected to the bottom plate 24 by soldering made at the collar 25. The edge 13 for securing the lid is substantially reinforced when a distance referenced D3 is provided between the bottom plate 24 and the end 17 of the doubled wall 16 brazed against the end tube 6a, 6b. Such a distance is at least 2 mm. This distance D3 is measured, for example, between a face of the bottom plate facing the heat exchange body 2 and a plane passing through a face of the second wall 22 soldered against the first wall. Advantageously, the distance D3 is at most equal to 6.5 mm. FIG. 4 is a view showing in detail the connection between the collector 3 and the side wall 18 of the tubes 6, 6a, 6b constituting the heat exchange body 2. This representation illustrates a section taken in the plane B shown in FIG. FIG. 1. The differences with FIG. 3 will be described, and reference will be made to the description with reference to implementing the structure of the common elements shown in FIG. 4. The strip 27 is perpendicularly disposed at the bottom plate 24 is brazed against the side wall 18 delimiting at least one tube 6 of the heat exchange body 2. Advantageously, such soldering is performed against the side wall 25 of each tube 6, including the end tubes 6a, 6b. This brazing is carried out over a distance referenced D4 which is minimum equal to 1 mm and maximum equal to 7.5 mm. This distance D4 is measured, for example, between an edge delimiting the opening of the tubes at the bottom plate 24 and a straight line passing through the bottom of the housing 26 delimited by the first band 28 constituting the first wall 21. The end 17 of the doubled wall 16 is also secured against the side wall 18 of at least one tube 6, similarly to the solutions described with reference to FIG. 3. Advantageously, this brazing of the end 17 is made against the side wall of each tube 6, including the end tubes 6a, 6b Note that the heat exchange body 2 and the collector 4 can be made from an aluminum alloy. The cover 4 can in turn be made of an aluminum alloy or a synthetic material.

The heat exchanger 1 described above can be integrated into an intake or exhaust gas cooling system of an internal combustion engine. In such a case, the first fluid is formed by the intake gases, in particular a supercharged air flow, while the second fluid is formed by a flow of air, for example outside the vehicle which receives such a system of air. cooling. The heat exchanger 1 is thus arranged so that the second fluid passes through the heat exchange body 2, dissipating the heat generated by the first fluid in the second fluid, by means of the tubes and dissipation devices. The second fluid passes through the heat exchange body 2 in a direction perpendicular to, or substantially perpendicular to, the direction of movement of the first fluid in the tubes 6. 2 99103 7 18

Claims (17)

REVENDICATIONS1. Heat exchanger (1) comprising an exchange body CLAIMS1. Heat exchanger (1) comprising a heat exchange body (2), at least one cover (4) and a collector (3) connecting the cover (4) to the heat exchange body (2) with the aid of a crimping device (8) issuing from the collector (3) and folded over the cover (4), the heat exchange body (2) comprising a plurality of tubes (6, 6a, 6b) able to channel a first fluid , the collector (3) comprising a bottom plate (24) surrounded by an edge (13) for securing the cover (4), characterized in that the bottom plate (24) and the joining edge (13) delimit a housing (26) for receiving a bead (15) of the cover (4), the joining edge (13) being formed by a doubled wall (16), one end (17) of which is secured to at least one tube (6); , 6a, 6b). 2. Exchanger according to claim 1, wherein the end (17) of the doubled wall (16) is secured to a plurality of tubes (6, 6a, 6b). 3. heat exchanger according to claim 2, wherein a tube (6, 6a, 6b) comprises two longitudinal walls (19) joined to one another by two side walls (18), the edge (13) of fastening comprising a strip (27) transverse to the bottom plate (24) and secured against at least one of the side walls (18) of at least one tube (6, 6a, 6b) over a length of at least 1 MM . 4. Exchanger according to one of claims 1 to 3, wherein the end (17) is secured against a longitudinal wall (19) of a terminal tube (6a, 6b) of the heat exchange body (2). 5. Exchanger according to claim 4, wherein the heat exchange body (2) is completed laterally by a cheek (14) installed at a distance (Di) from the doubled wall (16) at least equal to 0.1 mm. 6. Exchanger according to claim 5, wherein a dissipation device (7) is interposed between the cheek (14) and the end tube (6a, 6b), the dissipation device (7) being at a distance (D2) from the doubled wall (16) at least equal to 0.1 mm. 7. Exchanger according to claim 6, wherein a distance (D3) of at least 2 mm is provided between the bottom plate (24) and the end (17) of the doubled wall (16). 8. Exchanger according to any one of the preceding claims, wherein the bottom plate (24) comprises at least one opening in which is housed a tube end (6, 6a, 6b), said opening being bordered by a collar ( 25) facing the heat exchange body (2). 9. Exchanger according to any one of the preceding claims, comprising a seal (35) installed in the receiving housing (26) at least between the heel (15) of the cover (4) and the edge (13) of attachment. 10. Exchanger according to any one of the preceding claims, wherein the lined wall (16) is formed by a first wall (21) and a second wall (22) soldered against the first wall (21). 11. Exchanger according to claim 10, wherein the doubled wall (16) comprises at least one angle to the right of which is provided a mechanical reinforcement device. 12. Exchanger according to claim 11, wherein the mechanical reinforcement device is a chamfer (30) formed on the angle of the first wall (21). 13. Exchanger according to claim 11 or 12, wherein the mechanical reinforcing device is a fillet (33) formed on the angle of the second wall (22), the fillet (33) being formed in particular opposite the chamfer (30). ). 14. Exchanger according to claim 12, wherein the first wall (21) comprises a first band (28) forming a bottom of the housing (26) and a first sidewall (29) laterally delimiting the housing (26), the first band (28), 28) and the first sidewall (29) being connected by the chamfer (30). 15. Exchanger according to claim 14, wherein the second wall (22) comprises a second band (31) soldered against the first band (28), and a second side (32) brazed against the first sidewall (29), the second band (31) and the second flank (32) being connected by a fillet (33) remote from the chamfer (30). 16. Exchanger according to any one of claims 10 to 15, wherein the end (17) comprises a fold (34) arranged for a face of the second wall (22) is brazed against the tube (6, 6a , 6b). 17. Heat exchanger according to any one of claims 10 to 16, wherein the crimping device (8) comprises a plurality of crimping tabs (20) from the first wall (21). 20