Heat exchanger with brazed end flange

A heat exchanger for a motor vehicle includes heat exchange bundle with a plurality of stacked tubes inside which a first heat-transfer fluid circulates, and an end flange arranged on each side of the stack of tubes which brazed to the heat exchange bundle. The end flanges include a flat body with a first surface that faces an aerodynamic element and a second surface, the brazing surface, opposite to the first surface and brazed to the heat exchange bundle. Attachment tabs receive the aerodynamic element and are arranged on the sides of the flat body, the attachment tabs projecting in the opposite direction to the heat exchange bundle. At least one extension of the flat body extends in the same general plane as the flat body and is arranged between a pair of attachment tabs on a same side of the flat body.

The invention relates to the field of heat exchangers and more specifically to heat exchangers having a bundle of tubes and comprising end flanges.

Heat exchangers, for example air/heat-transfer fluid exchangers, generally include a heat exchange bundle comprising a plurality of stacked tubes. At the ends of the heat exchange bundle is arranged a manifold inside which the heat-transfer fluid is intended to circulate so that it circulates within the tubes. The air circulates between the tubes.

On either side of the stack of tubes of the heat exchange bundle, the heat exchanger generally comprises end flanges brazed to the heat exchange bundle. These end flanges allow in particular the attachment of an aerodynamic element such as a deflector or a seal in order to block or deflect the circulation of air on the sides of the heat exchanger. In order to attach this aerodynamic element, the edges of the end flange are raised to form a rim with which the aerodynamic element engages.

However, the fact that the edges of the end flange are raised may result in a decrease in the surface area for contact between said end flange and the heat exchange bundle. Consequently, the useful surface area for brazing between the end flange and the heat exchange bundle is also reduced and this can lead to end flange attachment defects. This is particularly the case with thin heat exchangers, for example having a thickness between 12 and 18 mm.

One of the aims of the present invention is to at least partially overcome the drawbacks of the prior art and to provide a heat exchanger with improved attachment of the end flanges.

The present invention therefore relates to a heat exchanger, in particular for a motor vehicle, comprising:a heat exchange bundle comprising a plurality of stacked tubes inside which a first heat-transfer fluid is intended to circulate, andan end flange arranged on each side of the stack of tubes, said end flange being brazed to the heat exchange bundle, the end flanges comprising:a flat body comprising a first surface intended to face an aerodynamic element and a second surface, referred to as the brazing surface, opposite to the first surface and brazed to the heat exchange bundle,attachment tabs configured to receive the aerodynamic element and arranged on the sides of said flat body, said attachment tabs projecting in the opposite direction to the heat exchange bundle,at least one extension of the flat body extending in the same general plane as said flat body and arranged between a pair of attachment tabs arranged on a same side of said flat body, such that the width of the flat body between said pair of attachment tabs and an attachment tab arranged on the opposite side of said flat body, facing the pair of attachment tabs, is less than the width of the flat body at the at least one extension.

This difference in width makes it possible to increase the general surface area of the flat body and in particular its second surface. Thus, the useful surface area for attaching the end flange to the heat exchange bundle is enlarged and allows better attachment. This is particularly useful in the case of thin heat exchangers which have a width of between 12 and 18 mm, for example.

According to one aspect of the invention, an extension is arranged between each pair of attachment tabs arranged along the sides of said flat body.

According to another aspect of the invention, the attachment tabs on a first side of the flat body are arranged facing the attachment tabs on a second side opposite to the first side, and that the extensions on the first side of the flat body are arranged facing the extensions on the second side.

According to another aspect of the invention, the attachment tabs on a first side are arranged facing the extensions on a second side opposite to the first side, and that the extensions on the first side are arranged facing the attachment tabs on the second side.

According to another aspect of the invention, the attachment tabs have at their top a hooking rim configured to retain the aerodynamic element.

According to another aspect of the invention, the attachment tabs on a same side are connected at their top by the hooking rim.

According to another aspect of the invention, the attachment tabs and the extensions of the flat body are integral with said flat body.

According to another aspect of the invention, the attachment tabs and the extensions of the flat body are produced by stamping.

In the various figures, identical elements bear the same reference numbers.

The following embodiments are examples. Although the description refers to one or more embodiments, this does not necessarily mean that each reference relates to the same embodiment, or that the features apply only to a single embodiment. Individual features of different embodiments can also be combined and/or interchanged to provide other embodiments.

In the present description, certain elements or parameters may be designated as first element or second element, for example, or first parameter and second parameter or first criterion and second criterion, etc. In this case, it is simply a designation to differentiate between and name elements or parameters or criteria that are similar but not identical. Such designation does not imply that one element, parameter or criterion has priority over another and such names can easily be interchanged without departing from the scope of the present description. Such designation also does not imply any chronological order, for example in assessing any given criterion.

FIG.1shows a partial semi-exploded view of a heat exchanger1. The heat exchanger1includes a heat exchange bundle3comprising a plurality of stacked tubes5and a manifold7. A manifold7is arranged at each end of the heat exchange bundle3. A heat-transfer fluid is intended to circulate within the heat exchanger1, more particularly in the manifolds7which redistribute the heat-transfer fluid in the tubes5. The manifold7comprises a manifold plate11through which the tubes5pass. The connection between the manifold plate11and the tubes5is sealed. This sealed connection can be achieved by brazing in the case of a heat exchanger referred to as brazed, or by means of one or more seals in the case of a mechanical or mechanical/brazed heat exchanger. The manifold plate11is covered by a cap9so as to form a free volume inside which the heat-transfer fluid circulates in order to be redistributed within the various tubes5. This cap9has an inlet and/or outlet for heat-transfer fluid (not visible).

Between the tubes5are arranged interfering elements (not shown), for example fins, for disturbing the flow of the second heat-transfer fluid, for example air, intended to circulate between said tubes5.

On each side of the stack of tubes5, there is an end flange13. This end flange13is made of metal, preferably the same metal as the tubes5or the interfering elements. The end flange13is brazed to the heat exchange bundle3. It may be brazed directly to a tube5or to a disturbing element placed on the side of the stack of tubes5. This end flange13is configured to allow the attachment of an aerodynamic element15, for example a deflector, or a seal in order to block or deflect the circulation of the second heat-transfer fluid on the sides of the heat exchanger1.

FIGS.2aand2bshow the structure of an end flange13in more detail. This end flange13includes a flat body130comprising a first surface130a(visible inFIG.2a) intended to be placed facing an aerodynamic element15, and a second surface130b(visible inFIG.2b), referred to as the brazing surface, opposite to the first surface130aand brazed to the heat exchange bundle3. The end flange13has a total width substantially equal to that of the heat exchanger1and more particularly that of its heat exchange bundle3, so that no element of the end flange13protrudes widthwise, in order to limit the size of the heat exchanger1.

The end flange13also has attachment tabs132configured to receive the aerodynamic element15. These attachment tabs132are arranged on the sides of said flat body130and project in the opposite direction to the heat exchange bundle3.

These attachment tabs132may in particular include, at their top, a hooking rim136configured to retain the aerodynamic element15. This hooking rim136may in particular constitute a recess in the attachment tab132on which is hooked a hooked rim154(visible inFIGS.3aand3b) of the aerodynamic element15.

The attachment tabs132may in particular be integral with the flat body130. The attachment tabs132may thus be produced by stamping. The hooking rim136must be contained within the total width of the end flange13and thus, in the area of the attachment tabs132, the width of the flat body130and therefore the second surface130bis reduced accordingly.

FIGS.3aand3bshow in more detail the structure of two halves of an aerodynamic element15, in particular the hooked rim154thereof. The aerodynamic element15in this case comprises a surface151and, on either side of this surface151, a bent portion153bent toward the inside of the surface151(inFIGS.3aand3b, only one bent portion153is shown instead of two). This bent portion153thus forms the hooked rim154which hooks onto the hooking rim136of the end flange13.

The aerodynamic element15may also include a leg152intended to bear on the first surface130aof the end flange13. The aerodynamic element15may be made of plastic or elastomer. The aerodynamic element15may be fitted on the end flange13by elastic deformation so that its hooked rims154engage with the hooking rims136of the attachment tabs132on both sides of the end flange13. The aerodynamic element15may also be fitted on the end flange13by sliding along the end flange13.

According to a first variant shown inFIG.3a, there are a single bent portion153and a single hooked rim154.

According to a second variant shown inFIG.3b, the bent portion153comprises a stop155which in combination with the hooked rim154forms a slide156into which the hooking rims136of the attachment tabs132are inserted.

Returning toFIGS.2aand2b, the end flange13also includes extensions134of the flat body130. These extensions134extend in the same general plane as the flat body130. At least one extension134is arranged between a pair of attachment tabs130arranged on the same side of said flat body130. In the example shown inFIGS.2aand2b, a single extension134is arranged between the pairs of attachments130. It is entirely possible to imagine an embodiment in which there are several extensions134between two attachment tabs130on the same side of the flat body130.

These extensions134are in particular arranged between the attachment tabs132of the pair of attachment tabs132such that the width L1of the flat body130between the pair of attachment tabs132and an attachment tab132arranged on the opposite side of said flat body130, facing the pair of attachment tabs132, is less than the width L2of the flat body130at the at least one extension134. This difference in width makes it possible to increase the general surface area of the flat body132and in particular its second surface130b. Thus the useful surface area for attaching the end flange13to the heat exchange bundle3is enlarged and allows better attachment. This is particularly useful in the context of thin heat exchangers1which have a width of between 12 and 18 mm, for example. These extensions134preferably have a length such that the total width of the sealing flange13does not exceed that of the heat exchanger1.

The extensions134may also in particular be integral with the flat body130. The extensions134may thus be produced by stamping.

The fact that the extensions134and the attachment tabs132may be integral with the flat body130allows the end flange13to be produced in one piece, which gives it greater strength. More particularly the extensions134and the attachment tabs132may be produced by stamping.

FIGS.2aand2bshow in particular an end flange13according to a first embodiment. In this first embodiment, the attachment tabs132on a first side of the flat body130are arranged facing the attachment tabs132on a second side, opposite to the first side. Likewise, the extensions134on the first side of the flat body130are arranged facing the extensions134on the second side.

FIGS.4aand4bshow a variant of the first embodiment ofFIGS.2aand2b. In this variant, the attachment tabs132on a same side are connected at their top by the hooking rim136. The extensions134are then arranged facing this hooking rim136connecting the tops of the attachment tabs132. This thus makes it possible to increase the surface area for hooking between the end flange13and the aerodynamic element15and thus to improve the attachment thereof, while still having a second surface130bsufficient for good brazing.

FIGS.5aand5bshow an end flange13according to a second embodiment. In this second embodiment, the attachment tabs132on a first side are arranged facing the extensions134on a second side opposite to the first side. Likewise, the extensions134on the first side are arranged facing the attachment tabs132on the second side.

FIGS.6aand6bshow a variant of this second embodiment ofFIGS.5aand5b. In this variant, the attachment tabs132on a same side are connected at their top by the hooking rim136. This thus makes it possible to increase the surface area for hooking between the end flange13and the aerodynamic element15and thus to improve the attachment thereof, while still having a second surface130bsufficient for good brazing.

Thus, it can be clearly seen that by virtue of the structure of the end flange13with alternating attachment tabs132and extensions134, the second surface130bis increased, allowing better attachment by brazing of the end flange13to the heat exchange bundle3.